diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 43dc35f..eb9a73a 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5497,6 +5497,15 @@ stifb= [HW] Format: bpp:[:[:...]] + strict_sas_size= + [X86] + Format: + Enable or disable strict sigaltstack size checks + against the required signal frame size which + depends on the supported FPU features. This can + be used to filter out binaries which have + not yet been made aware of AT_MINSIGSTKSZ. + sunrpc.min_resvport= sunrpc.max_resvport= [NFS,SUNRPC] diff --git a/Documentation/x86/index.rst b/Documentation/x86/index.rst index 3830483..f498f1d 100644 --- a/Documentation/x86/index.rst +++ b/Documentation/x86/index.rst @@ -37,3 +37,4 @@ x86-specific Documentation sgx features elf_auxvec + xstate diff --git a/Documentation/x86/xstate.rst b/Documentation/x86/xstate.rst new file mode 100644 index 0000000..65de3f0 --- /dev/null +++ b/Documentation/x86/xstate.rst @@ -0,0 +1,65 @@ +Using XSTATE features in user space applications +================================================ + +The x86 architecture supports floating-point extensions which are +enumerated via CPUID. Applications consult CPUID and use XGETBV to +evaluate which features have been enabled by the kernel XCR0. + +Up to AVX-512 and PKRU states, these features are automatically enabled by +the kernel if available. Features like AMX TILE_DATA (XSTATE component 18) +are enabled by XCR0 as well, but the first use of related instruction is +trapped by the kernel because by default the required large XSTATE buffers +are not allocated automatically. + +Using dynamically enabled XSTATE features in user space applications +-------------------------------------------------------------------- + +The kernel provides an arch_prctl(2) based mechanism for applications to +request the usage of such features. The arch_prctl(2) options related to +this are: + +-ARCH_GET_XCOMP_SUPP + + arch_prctl(ARCH_GET_XCOMP_SUPP, &features); + + ARCH_GET_XCOMP_SUPP stores the supported features in userspace storage of + type uint64_t. The second argument is a pointer to that storage. + +-ARCH_GET_XCOMP_PERM + + arch_prctl(ARCH_GET_XCOMP_PERM, &features); + + ARCH_GET_XCOMP_PERM stores the features for which the userspace process + has permission in userspace storage of type uint64_t. The second argument + is a pointer to that storage. + +-ARCH_REQ_XCOMP_PERM + + arch_prctl(ARCH_REQ_XCOMP_PERM, feature_nr); + + ARCH_REQ_XCOMP_PERM allows to request permission for a dynamically enabled + feature or a feature set. A feature set can be mapped to a facility, e.g. + AMX, and can require one or more XSTATE components to be enabled. + + The feature argument is the number of the highest XSTATE component which + is required for a facility to work. + +When requesting permission for a feature, the kernel checks the +availability. The kernel ensures that sigaltstacks in the process's tasks +are large enough to accommodate the resulting large signal frame. It +enforces this both during ARCH_REQ_XCOMP_SUPP and during any subsequent +sigaltstack(2) calls. If an installed sigaltstack is smaller than the +resulting sigframe size, ARCH_REQ_XCOMP_SUPP results in -ENOSUPP. Also, +sigaltstack(2) results in -ENOMEM if the requested altstack is too small +for the permitted features. + +Permission, when granted, is valid per process. Permissions are inherited +on fork(2) and cleared on exec(3). + +The first use of an instruction related to a dynamically enabled feature is +trapped by the kernel. The trap handler checks whether the process has +permission to use the feature. If the process has no permission then the +kernel sends SIGILL to the application. If the process has permission then +the handler allocates a larger xstate buffer for the task so the large +state can be context switched. In the unlikely cases that the allocation +fails, the kernel sends SIGSEGV. diff --git a/arch/Kconfig b/arch/Kconfig index 8df1c71..af5cf30 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -1288,6 +1288,9 @@ config ARCH_HAS_ELFCORE_COMPAT config ARCH_HAS_PARANOID_L1D_FLUSH bool +config DYNAMIC_SIGFRAME + bool + source "kernel/gcov/Kconfig" source "scripts/gcc-plugins/Kconfig" diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index cdaeccc..244d3a4 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -125,6 +125,7 @@ config X86 select CLOCKSOURCE_VALIDATE_LAST_CYCLE select CLOCKSOURCE_WATCHDOG select DCACHE_WORD_ACCESS + select DYNAMIC_SIGFRAME select EDAC_ATOMIC_SCRUB select EDAC_SUPPORT select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC) @@ -2399,6 +2400,22 @@ config MODIFY_LDT_SYSCALL Saying 'N' here may make sense for embedded or server kernels. +config STRICT_SIGALTSTACK_SIZE + bool "Enforce strict size checking for sigaltstack" + depends on DYNAMIC_SIGFRAME + help + For historical reasons MINSIGSTKSZ is a constant which became + already too small with AVX512 support. Add a mechanism to + enforce strict checking of the sigaltstack size against the + real size of the FPU frame. This option enables the check + by default. It can also be controlled via the kernel command + line option 'strict_sas_size' independent of this config + switch. Enabling it might break existing applications which + allocate a too small sigaltstack but 'work' because they + never get a signal delivered. + + Say 'N' unless you want to really enforce this check. + source "kernel/livepatch/Kconfig" endmenu diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h index 76436a5..7b5167d 100644 --- a/arch/x86/events/perf_event.h +++ b/arch/x86/events/perf_event.h @@ -14,6 +14,7 @@ #include +#include #include #include diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c index 5e3d9b7..c9c3859 100644 --- a/arch/x86/ia32/ia32_signal.c +++ b/arch/x86/ia32/ia32_signal.c @@ -24,7 +24,6 @@ #include #include #include -#include #include #include #include @@ -57,8 +56,8 @@ static inline void reload_segments(struct sigcontext_32 *sc) /* * Do a signal return; undo the signal stack. */ -static int ia32_restore_sigcontext(struct pt_regs *regs, - struct sigcontext_32 __user *usc) +static bool ia32_restore_sigcontext(struct pt_regs *regs, + struct sigcontext_32 __user *usc) { struct sigcontext_32 sc; @@ -66,7 +65,7 @@ static int ia32_restore_sigcontext(struct pt_regs *regs, current->restart_block.fn = do_no_restart_syscall; if (unlikely(copy_from_user(&sc, usc, sizeof(sc)))) - return -EFAULT; + return false; /* Get only the ia32 registers. */ regs->bx = sc.bx; @@ -111,7 +110,7 @@ COMPAT_SYSCALL_DEFINE0(sigreturn) set_current_blocked(&set); - if (ia32_restore_sigcontext(regs, &frame->sc)) + if (!ia32_restore_sigcontext(regs, &frame->sc)) goto badframe; return regs->ax; @@ -135,7 +134,7 @@ COMPAT_SYSCALL_DEFINE0(rt_sigreturn) set_current_blocked(&set); - if (ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext)) + if (!ia32_restore_sigcontext(regs, &frame->uc.uc_mcontext)) goto badframe; if (compat_restore_altstack(&frame->uc.uc_stack)) @@ -220,8 +219,8 @@ static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size); *fpstate = (struct _fpstate_32 __user *) sp; - if (copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned, - math_size) < 0) + if (!copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned, + math_size)) return (void __user *) -1L; sp -= frame_size; diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h index 3ad3da9..6aadb9a 100644 --- a/arch/x86/include/asm/asm.h +++ b/arch/x86/include/asm/asm.h @@ -122,28 +122,19 @@ #ifdef __KERNEL__ +# include + /* Exception table entry */ #ifdef __ASSEMBLY__ -# define _ASM_EXTABLE_HANDLE(from, to, handler) \ + +# define _ASM_EXTABLE_TYPE(from, to, type) \ .pushsection "__ex_table","a" ; \ .balign 4 ; \ .long (from) - . ; \ .long (to) - . ; \ - .long (handler) - . ; \ + .long type ; \ .popsection -# define _ASM_EXTABLE(from, to) \ - _ASM_EXTABLE_HANDLE(from, to, ex_handler_default) - -# define _ASM_EXTABLE_UA(from, to) \ - _ASM_EXTABLE_HANDLE(from, to, ex_handler_uaccess) - -# define _ASM_EXTABLE_CPY(from, to) \ - _ASM_EXTABLE_HANDLE(from, to, ex_handler_copy) - -# define _ASM_EXTABLE_FAULT(from, to) \ - _ASM_EXTABLE_HANDLE(from, to, ex_handler_fault) - # ifdef CONFIG_KPROBES # define _ASM_NOKPROBE(entry) \ .pushsection "_kprobe_blacklist","aw" ; \ @@ -155,27 +146,15 @@ # endif #else /* ! __ASSEMBLY__ */ -# define _EXPAND_EXTABLE_HANDLE(x) #x -# define _ASM_EXTABLE_HANDLE(from, to, handler) \ + +# define _ASM_EXTABLE_TYPE(from, to, type) \ " .pushsection \"__ex_table\",\"a\"\n" \ " .balign 4\n" \ " .long (" #from ") - .\n" \ " .long (" #to ") - .\n" \ - " .long (" _EXPAND_EXTABLE_HANDLE(handler) ") - .\n" \ + " .long " __stringify(type) " \n" \ " .popsection\n" -# define _ASM_EXTABLE(from, to) \ - _ASM_EXTABLE_HANDLE(from, to, ex_handler_default) - -# define _ASM_EXTABLE_UA(from, to) \ - _ASM_EXTABLE_HANDLE(from, to, ex_handler_uaccess) - -# define _ASM_EXTABLE_CPY(from, to) \ - _ASM_EXTABLE_HANDLE(from, to, ex_handler_copy) - -# define _ASM_EXTABLE_FAULT(from, to) \ - _ASM_EXTABLE_HANDLE(from, to, ex_handler_fault) - /* For C file, we already have NOKPROBE_SYMBOL macro */ /* @@ -188,6 +167,17 @@ register unsigned long current_stack_pointer asm(_ASM_SP); #define ASM_CALL_CONSTRAINT "+r" (current_stack_pointer) #endif /* __ASSEMBLY__ */ -#endif /* __KERNEL__ */ +#define _ASM_EXTABLE(from, to) \ + _ASM_EXTABLE_TYPE(from, to, EX_TYPE_DEFAULT) +#define _ASM_EXTABLE_UA(from, to) \ + _ASM_EXTABLE_TYPE(from, to, EX_TYPE_UACCESS) + +#define _ASM_EXTABLE_CPY(from, to) \ + _ASM_EXTABLE_TYPE(from, to, EX_TYPE_COPY) + +#define _ASM_EXTABLE_FAULT(from, to) \ + _ASM_EXTABLE_TYPE(from, to, EX_TYPE_FAULT) + +#endif /* __KERNEL__ */ #endif /* _ASM_X86_ASM_H */ diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index d0ce5cf..d5b5f2a 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -277,6 +277,7 @@ #define X86_FEATURE_XSAVEC (10*32+ 1) /* XSAVEC instruction */ #define X86_FEATURE_XGETBV1 (10*32+ 2) /* XGETBV with ECX = 1 instruction */ #define X86_FEATURE_XSAVES (10*32+ 3) /* XSAVES/XRSTORS instructions */ +#define X86_FEATURE_XFD (10*32+ 4) /* "" eXtended Feature Disabling */ /* * Extended auxiliary flags: Linux defined - for features scattered in various @@ -298,6 +299,7 @@ /* Intel-defined CPU features, CPUID level 0x00000007:1 (EAX), word 12 */ #define X86_FEATURE_AVX_VNNI (12*32+ 4) /* AVX VNNI instructions */ #define X86_FEATURE_AVX512_BF16 (12*32+ 5) /* AVX512 BFLOAT16 instructions */ +#define X86_FEATURE_AMX_TILE (18*32+24) /* AMX tile Support */ /* AMD-defined CPU features, CPUID level 0x80000008 (EBX), word 13 */ #define X86_FEATURE_CLZERO (13*32+ 0) /* CLZERO instruction */ diff --git a/arch/x86/include/asm/extable.h b/arch/x86/include/asm/extable.h index 1f0cbc5..93f400e 100644 --- a/arch/x86/include/asm/extable.h +++ b/arch/x86/include/asm/extable.h @@ -1,12 +1,18 @@ /* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_X86_EXTABLE_H #define _ASM_X86_EXTABLE_H + +#include + /* - * The exception table consists of triples of addresses relative to the - * exception table entry itself. The first address is of an instruction - * that is allowed to fault, the second is the target at which the program - * should continue. The third is a handler function to deal with the fault - * caused by the instruction in the first field. + * The exception table consists of two addresses relative to the + * exception table entry itself and a type selector field. + * + * The first address is of an instruction that is allowed to fault, the + * second is the target at which the program should continue. + * + * The type entry is used by fixup_exception() to select the handler to + * deal with the fault caused by the instruction in the first field. * * All the routines below use bits of fixup code that are out of line * with the main instruction path. This means when everything is well, @@ -15,7 +21,7 @@ */ struct exception_table_entry { - int insn, fixup, handler; + int insn, fixup, type; }; struct pt_regs; @@ -25,21 +31,27 @@ struct pt_regs; do { \ (a)->fixup = (b)->fixup + (delta); \ (b)->fixup = (tmp).fixup - (delta); \ - (a)->handler = (b)->handler + (delta); \ - (b)->handler = (tmp).handler - (delta); \ + (a)->type = (b)->type; \ + (b)->type = (tmp).type; \ } while (0) -enum handler_type { - EX_HANDLER_NONE, - EX_HANDLER_FAULT, - EX_HANDLER_UACCESS, - EX_HANDLER_OTHER -}; - extern int fixup_exception(struct pt_regs *regs, int trapnr, unsigned long error_code, unsigned long fault_addr); extern int fixup_bug(struct pt_regs *regs, int trapnr); -extern enum handler_type ex_get_fault_handler_type(unsigned long ip); +extern int ex_get_fixup_type(unsigned long ip); extern void early_fixup_exception(struct pt_regs *regs, int trapnr); +#ifdef CONFIG_X86_MCE +extern void ex_handler_msr_mce(struct pt_regs *regs, bool wrmsr); +#else +static inline void ex_handler_msr_mce(struct pt_regs *regs, bool wrmsr) { } +#endif + +#if defined(CONFIG_BPF_JIT) && defined(CONFIG_X86_64) +bool ex_handler_bpf(const struct exception_table_entry *x, struct pt_regs *regs); +#else +static inline bool ex_handler_bpf(const struct exception_table_entry *x, + struct pt_regs *regs) { return false; } +#endif + #endif diff --git a/arch/x86/include/asm/extable_fixup_types.h b/arch/x86/include/asm/extable_fixup_types.h new file mode 100644 index 0000000..409524d --- /dev/null +++ b/arch/x86/include/asm/extable_fixup_types.h @@ -0,0 +1,22 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_EXTABLE_FIXUP_TYPES_H +#define _ASM_X86_EXTABLE_FIXUP_TYPES_H + +#define EX_TYPE_NONE 0 +#define EX_TYPE_DEFAULT 1 +#define EX_TYPE_FAULT 2 +#define EX_TYPE_UACCESS 3 +#define EX_TYPE_COPY 4 +#define EX_TYPE_CLEAR_FS 5 +#define EX_TYPE_FPU_RESTORE 6 +#define EX_TYPE_WRMSR 7 +#define EX_TYPE_RDMSR 8 +#define EX_TYPE_BPF 9 + +#define EX_TYPE_WRMSR_IN_MCE 10 +#define EX_TYPE_RDMSR_IN_MCE 11 + +#define EX_TYPE_DEFAULT_MCE_SAFE 12 +#define EX_TYPE_FAULT_MCE_SAFE 13 + +#endif diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h index 23bef08..b7267b9 100644 --- a/arch/x86/include/asm/fpu/api.h +++ b/arch/x86/include/asm/fpu/api.h @@ -12,6 +12,8 @@ #define _ASM_X86_FPU_API_H #include +#include + /* * Use kernel_fpu_begin/end() if you intend to use FPU in kernel context. It * disables preemption so be careful if you intend to use it for long periods @@ -48,9 +50,9 @@ static inline void kernel_fpu_begin(void) } /* - * Use fpregs_lock() while editing CPU's FPU registers or fpu->state. + * Use fpregs_lock() while editing CPU's FPU registers or fpu->fpstate. * A context switch will (and softirq might) save CPU's FPU registers to - * fpu->state and set TIF_NEED_FPU_LOAD leaving CPU's FPU registers in + * fpu->fpstate.regs and set TIF_NEED_FPU_LOAD leaving CPU's FPU registers in * a random state. * * local_bh_disable() protects against both preemption and soft interrupts @@ -108,4 +110,56 @@ extern int cpu_has_xfeatures(u64 xfeatures_mask, const char **feature_name); static inline void update_pasid(void) { } +/* Trap handling */ +extern int fpu__exception_code(struct fpu *fpu, int trap_nr); +extern void fpu_sync_fpstate(struct fpu *fpu); +extern void fpu_reset_from_exception_fixup(void); + +/* Boot, hotplug and resume */ +extern void fpu__init_cpu(void); +extern void fpu__init_system(struct cpuinfo_x86 *c); +extern void fpu__init_check_bugs(void); +extern void fpu__resume_cpu(void); + +#ifdef CONFIG_MATH_EMULATION +extern void fpstate_init_soft(struct swregs_state *soft); +#else +static inline void fpstate_init_soft(struct swregs_state *soft) {} +#endif + +/* State tracking */ +DECLARE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx); + +/* Process cleanup */ +#ifdef CONFIG_X86_64 +extern void fpstate_free(struct fpu *fpu); +#else +static inline void fpstate_free(struct fpu *fpu) { } +#endif + +/* fpstate-related functions which are exported to KVM */ +extern void fpstate_clear_xstate_component(struct fpstate *fps, unsigned int xfeature); + +/* KVM specific functions */ +extern bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu); +extern void fpu_free_guest_fpstate(struct fpu_guest *gfpu); +extern int fpu_swap_kvm_fpstate(struct fpu_guest *gfpu, bool enter_guest); + +extern void fpu_copy_guest_fpstate_to_uabi(struct fpu_guest *gfpu, void *buf, unsigned int size, u32 pkru); +extern int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, const void *buf, u64 xcr0, u32 *vpkru); + +static inline void fpstate_set_confidential(struct fpu_guest *gfpu) +{ + gfpu->fpstate->is_confidential = true; +} + +static inline bool fpstate_is_confidential(struct fpu_guest *gfpu) +{ + return gfpu->fpstate->is_confidential; +} + +/* prctl */ +struct task_struct; +extern long fpu_xstate_prctl(struct task_struct *tsk, int option, unsigned long arg2); + #endif /* _ASM_X86_FPU_API_H */ diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 5a18694..e69de29 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -1,540 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -/* - * Copyright (C) 1994 Linus Torvalds - * - * Pentium III FXSR, SSE support - * General FPU state handling cleanups - * Gareth Hughes , May 2000 - * x86-64 work by Andi Kleen 2002 - */ - -#ifndef _ASM_X86_FPU_INTERNAL_H -#define _ASM_X86_FPU_INTERNAL_H - -#include -#include -#include -#include - -#include -#include -#include -#include -#include -#include - -/* - * High level FPU state handling functions: - */ -extern int fpu__restore_sig(void __user *buf, int ia32_frame); -extern void fpu__drop(struct fpu *fpu); -extern void fpu__clear_user_states(struct fpu *fpu); -extern int fpu__exception_code(struct fpu *fpu, int trap_nr); - -extern void fpu_sync_fpstate(struct fpu *fpu); - -/* Clone and exit operations */ -extern int fpu_clone(struct task_struct *dst); -extern void fpu_flush_thread(void); - -/* - * Boot time FPU initialization functions: - */ -extern void fpu__init_cpu(void); -extern void fpu__init_system_xstate(void); -extern void fpu__init_cpu_xstate(void); -extern void fpu__init_system(struct cpuinfo_x86 *c); -extern void fpu__init_check_bugs(void); -extern void fpu__resume_cpu(void); - -/* - * Debugging facility: - */ -#ifdef CONFIG_X86_DEBUG_FPU -# define WARN_ON_FPU(x) WARN_ON_ONCE(x) -#else -# define WARN_ON_FPU(x) ({ (void)(x); 0; }) -#endif - -/* - * FPU related CPU feature flag helper routines: - */ -static __always_inline __pure bool use_xsaveopt(void) -{ - return static_cpu_has(X86_FEATURE_XSAVEOPT); -} - -static __always_inline __pure bool use_xsave(void) -{ - return static_cpu_has(X86_FEATURE_XSAVE); -} - -static __always_inline __pure bool use_fxsr(void) -{ - return static_cpu_has(X86_FEATURE_FXSR); -} - -/* - * fpstate handling functions: - */ - -extern union fpregs_state init_fpstate; - -extern void fpstate_init(union fpregs_state *state); -#ifdef CONFIG_MATH_EMULATION -extern void fpstate_init_soft(struct swregs_state *soft); -#else -static inline void fpstate_init_soft(struct swregs_state *soft) {} -#endif -extern void save_fpregs_to_fpstate(struct fpu *fpu); - -/* Returns 0 or the negated trap number, which results in -EFAULT for #PF */ -#define user_insn(insn, output, input...) \ -({ \ - int err; \ - \ - might_fault(); \ - \ - asm volatile(ASM_STAC "\n" \ - "1: " #insn "\n" \ - "2: " ASM_CLAC "\n" \ - ".section .fixup,\"ax\"\n" \ - "3: negl %%eax\n" \ - " jmp 2b\n" \ - ".previous\n" \ - _ASM_EXTABLE_FAULT(1b, 3b) \ - : [err] "=a" (err), output \ - : "0"(0), input); \ - err; \ -}) - -#define kernel_insn_err(insn, output, input...) \ -({ \ - int err; \ - asm volatile("1:" #insn "\n\t" \ - "2:\n" \ - ".section .fixup,\"ax\"\n" \ - "3: movl $-1,%[err]\n" \ - " jmp 2b\n" \ - ".previous\n" \ - _ASM_EXTABLE(1b, 3b) \ - : [err] "=r" (err), output \ - : "0"(0), input); \ - err; \ -}) - -#define kernel_insn(insn, output, input...) \ - asm volatile("1:" #insn "\n\t" \ - "2:\n" \ - _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_fprestore) \ - : output : input) - -static inline int fnsave_to_user_sigframe(struct fregs_state __user *fx) -{ - return user_insn(fnsave %[fx]; fwait, [fx] "=m" (*fx), "m" (*fx)); -} - -static inline int fxsave_to_user_sigframe(struct fxregs_state __user *fx) -{ - if (IS_ENABLED(CONFIG_X86_32)) - return user_insn(fxsave %[fx], [fx] "=m" (*fx), "m" (*fx)); - else - return user_insn(fxsaveq %[fx], [fx] "=m" (*fx), "m" (*fx)); - -} - -static inline void fxrstor(struct fxregs_state *fx) -{ - if (IS_ENABLED(CONFIG_X86_32)) - kernel_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx)); - else - kernel_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx)); -} - -static inline int fxrstor_safe(struct fxregs_state *fx) -{ - if (IS_ENABLED(CONFIG_X86_32)) - return kernel_insn_err(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx)); - else - return kernel_insn_err(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx)); -} - -static inline int fxrstor_from_user_sigframe(struct fxregs_state __user *fx) -{ - if (IS_ENABLED(CONFIG_X86_32)) - return user_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx)); - else - return user_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx)); -} - -static inline void frstor(struct fregs_state *fx) -{ - kernel_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx)); -} - -static inline int frstor_safe(struct fregs_state *fx) -{ - return kernel_insn_err(frstor %[fx], "=m" (*fx), [fx] "m" (*fx)); -} - -static inline int frstor_from_user_sigframe(struct fregs_state __user *fx) -{ - return user_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx)); -} - -static inline void fxsave(struct fxregs_state *fx) -{ - if (IS_ENABLED(CONFIG_X86_32)) - asm volatile( "fxsave %[fx]" : [fx] "=m" (*fx)); - else - asm volatile("fxsaveq %[fx]" : [fx] "=m" (*fx)); -} - -/* These macros all use (%edi)/(%rdi) as the single memory argument. */ -#define XSAVE ".byte " REX_PREFIX "0x0f,0xae,0x27" -#define XSAVEOPT ".byte " REX_PREFIX "0x0f,0xae,0x37" -#define XSAVES ".byte " REX_PREFIX "0x0f,0xc7,0x2f" -#define XRSTOR ".byte " REX_PREFIX "0x0f,0xae,0x2f" -#define XRSTORS ".byte " REX_PREFIX "0x0f,0xc7,0x1f" - -/* - * After this @err contains 0 on success or the negated trap number when - * the operation raises an exception. For faults this results in -EFAULT. - */ -#define XSTATE_OP(op, st, lmask, hmask, err) \ - asm volatile("1:" op "\n\t" \ - "xor %[err], %[err]\n" \ - "2:\n\t" \ - ".pushsection .fixup,\"ax\"\n\t" \ - "3: negl %%eax\n\t" \ - "jmp 2b\n\t" \ - ".popsection\n\t" \ - _ASM_EXTABLE_FAULT(1b, 3b) \ - : [err] "=a" (err) \ - : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \ - : "memory") - -/* - * If XSAVES is enabled, it replaces XSAVEOPT because it supports a compact - * format and supervisor states in addition to modified optimization in - * XSAVEOPT. - * - * Otherwise, if XSAVEOPT is enabled, XSAVEOPT replaces XSAVE because XSAVEOPT - * supports modified optimization which is not supported by XSAVE. - * - * We use XSAVE as a fallback. - * - * The 661 label is defined in the ALTERNATIVE* macros as the address of the - * original instruction which gets replaced. We need to use it here as the - * address of the instruction where we might get an exception at. - */ -#define XSTATE_XSAVE(st, lmask, hmask, err) \ - asm volatile(ALTERNATIVE_2(XSAVE, \ - XSAVEOPT, X86_FEATURE_XSAVEOPT, \ - XSAVES, X86_FEATURE_XSAVES) \ - "\n" \ - "xor %[err], %[err]\n" \ - "3:\n" \ - ".pushsection .fixup,\"ax\"\n" \ - "4: movl $-2, %[err]\n" \ - "jmp 3b\n" \ - ".popsection\n" \ - _ASM_EXTABLE(661b, 4b) \ - : [err] "=r" (err) \ - : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \ - : "memory") - -/* - * Use XRSTORS to restore context if it is enabled. XRSTORS supports compact - * XSAVE area format. - */ -#define XSTATE_XRESTORE(st, lmask, hmask) \ - asm volatile(ALTERNATIVE(XRSTOR, \ - XRSTORS, X86_FEATURE_XSAVES) \ - "\n" \ - "3:\n" \ - _ASM_EXTABLE_HANDLE(661b, 3b, ex_handler_fprestore)\ - : \ - : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \ - : "memory") - -/* - * This function is called only during boot time when x86 caps are not set - * up and alternative can not be used yet. - */ -static inline void os_xrstor_booting(struct xregs_state *xstate) -{ - u64 mask = xfeatures_mask_fpstate(); - u32 lmask = mask; - u32 hmask = mask >> 32; - int err; - - WARN_ON(system_state != SYSTEM_BOOTING); - - if (boot_cpu_has(X86_FEATURE_XSAVES)) - XSTATE_OP(XRSTORS, xstate, lmask, hmask, err); - else - XSTATE_OP(XRSTOR, xstate, lmask, hmask, err); - - /* - * We should never fault when copying from a kernel buffer, and the FPU - * state we set at boot time should be valid. - */ - WARN_ON_FPU(err); -} - -/* - * Save processor xstate to xsave area. - * - * Uses either XSAVE or XSAVEOPT or XSAVES depending on the CPU features - * and command line options. The choice is permanent until the next reboot. - */ -static inline void os_xsave(struct xregs_state *xstate) -{ - u64 mask = xfeatures_mask_all; - u32 lmask = mask; - u32 hmask = mask >> 32; - int err; - - WARN_ON_FPU(!alternatives_patched); - - XSTATE_XSAVE(xstate, lmask, hmask, err); - - /* We should never fault when copying to a kernel buffer: */ - WARN_ON_FPU(err); -} - -/* - * Restore processor xstate from xsave area. - * - * Uses XRSTORS when XSAVES is used, XRSTOR otherwise. - */ -static inline void os_xrstor(struct xregs_state *xstate, u64 mask) -{ - u32 lmask = mask; - u32 hmask = mask >> 32; - - XSTATE_XRESTORE(xstate, lmask, hmask); -} - -/* - * Save xstate to user space xsave area. - * - * We don't use modified optimization because xrstor/xrstors might track - * a different application. - * - * We don't use compacted format xsave area for - * backward compatibility for old applications which don't understand - * compacted format of xsave area. - */ -static inline int xsave_to_user_sigframe(struct xregs_state __user *buf) -{ - /* - * Include the features which are not xsaved/rstored by the kernel - * internally, e.g. PKRU. That's user space ABI and also required - * to allow the signal handler to modify PKRU. - */ - u64 mask = xfeatures_mask_uabi(); - u32 lmask = mask; - u32 hmask = mask >> 32; - int err; - - /* - * Clear the xsave header first, so that reserved fields are - * initialized to zero. - */ - err = __clear_user(&buf->header, sizeof(buf->header)); - if (unlikely(err)) - return -EFAULT; - - stac(); - XSTATE_OP(XSAVE, buf, lmask, hmask, err); - clac(); - - return err; -} - -/* - * Restore xstate from user space xsave area. - */ -static inline int xrstor_from_user_sigframe(struct xregs_state __user *buf, u64 mask) -{ - struct xregs_state *xstate = ((__force struct xregs_state *)buf); - u32 lmask = mask; - u32 hmask = mask >> 32; - int err; - - stac(); - XSTATE_OP(XRSTOR, xstate, lmask, hmask, err); - clac(); - - return err; -} - -/* - * Restore xstate from kernel space xsave area, return an error code instead of - * an exception. - */ -static inline int os_xrstor_safe(struct xregs_state *xstate, u64 mask) -{ - u32 lmask = mask; - u32 hmask = mask >> 32; - int err; - - if (cpu_feature_enabled(X86_FEATURE_XSAVES)) - XSTATE_OP(XRSTORS, xstate, lmask, hmask, err); - else - XSTATE_OP(XRSTOR, xstate, lmask, hmask, err); - - return err; -} - -extern void __restore_fpregs_from_fpstate(union fpregs_state *fpstate, u64 mask); - -static inline void restore_fpregs_from_fpstate(union fpregs_state *fpstate) -{ - __restore_fpregs_from_fpstate(fpstate, xfeatures_mask_fpstate()); -} - -extern int copy_fpstate_to_sigframe(void __user *buf, void __user *fp, int size); - -/* - * FPU context switch related helper methods: - */ - -DECLARE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx); - -/* - * The in-register FPU state for an FPU context on a CPU is assumed to be - * valid if the fpu->last_cpu matches the CPU, and the fpu_fpregs_owner_ctx - * matches the FPU. - * - * If the FPU register state is valid, the kernel can skip restoring the - * FPU state from memory. - * - * Any code that clobbers the FPU registers or updates the in-memory - * FPU state for a task MUST let the rest of the kernel know that the - * FPU registers are no longer valid for this task. - * - * Either one of these invalidation functions is enough. Invalidate - * a resource you control: CPU if using the CPU for something else - * (with preemption disabled), FPU for the current task, or a task that - * is prevented from running by the current task. - */ -static inline void __cpu_invalidate_fpregs_state(void) -{ - __this_cpu_write(fpu_fpregs_owner_ctx, NULL); -} - -static inline void __fpu_invalidate_fpregs_state(struct fpu *fpu) -{ - fpu->last_cpu = -1; -} - -static inline int fpregs_state_valid(struct fpu *fpu, unsigned int cpu) -{ - return fpu == this_cpu_read(fpu_fpregs_owner_ctx) && cpu == fpu->last_cpu; -} - -/* - * These generally need preemption protection to work, - * do try to avoid using these on their own: - */ -static inline void fpregs_deactivate(struct fpu *fpu) -{ - this_cpu_write(fpu_fpregs_owner_ctx, NULL); - trace_x86_fpu_regs_deactivated(fpu); -} - -static inline void fpregs_activate(struct fpu *fpu) -{ - this_cpu_write(fpu_fpregs_owner_ctx, fpu); - trace_x86_fpu_regs_activated(fpu); -} - -/* Internal helper for switch_fpu_return() and signal frame setup */ -static inline void fpregs_restore_userregs(void) -{ - struct fpu *fpu = ¤t->thread.fpu; - int cpu = smp_processor_id(); - - if (WARN_ON_ONCE(current->flags & PF_KTHREAD)) - return; - - if (!fpregs_state_valid(fpu, cpu)) { - u64 mask; - - /* - * This restores _all_ xstate which has not been - * established yet. - * - * If PKRU is enabled, then the PKRU value is already - * correct because it was either set in switch_to() or in - * flush_thread(). So it is excluded because it might be - * not up to date in current->thread.fpu.xsave state. - */ - mask = xfeatures_mask_restore_user() | - xfeatures_mask_supervisor(); - __restore_fpregs_from_fpstate(&fpu->state, mask); - - fpregs_activate(fpu); - fpu->last_cpu = cpu; - } - clear_thread_flag(TIF_NEED_FPU_LOAD); -} - -/* - * FPU state switching for scheduling. - * - * This is a two-stage process: - * - * - switch_fpu_prepare() saves the old state. - * This is done within the context of the old process. - * - * - switch_fpu_finish() sets TIF_NEED_FPU_LOAD; the floating point state - * will get loaded on return to userspace, or when the kernel needs it. - * - * If TIF_NEED_FPU_LOAD is cleared then the CPU's FPU registers - * are saved in the current thread's FPU register state. - * - * If TIF_NEED_FPU_LOAD is set then CPU's FPU registers may not - * hold current()'s FPU registers. It is required to load the - * registers before returning to userland or using the content - * otherwise. - * - * The FPU context is only stored/restored for a user task and - * PF_KTHREAD is used to distinguish between kernel and user threads. - */ -static inline void switch_fpu_prepare(struct fpu *old_fpu, int cpu) -{ - if (static_cpu_has(X86_FEATURE_FPU) && !(current->flags & PF_KTHREAD)) { - save_fpregs_to_fpstate(old_fpu); - /* - * The save operation preserved register state, so the - * fpu_fpregs_owner_ctx is still @old_fpu. Store the - * current CPU number in @old_fpu, so the next return - * to user space can avoid the FPU register restore - * when is returns on the same CPU and still owns the - * context. - */ - old_fpu->last_cpu = cpu; - - trace_x86_fpu_regs_deactivated(old_fpu); - } -} - -/* - * Misc helper functions: - */ - -/* - * Delay loading of the complete FPU state until the return to userland. - * PKRU is handled separately. - */ -static inline void switch_fpu_finish(struct fpu *new_fpu) -{ - if (cpu_feature_enabled(X86_FEATURE_FPU)) - set_thread_flag(TIF_NEED_FPU_LOAD); -} - -#endif /* _ASM_X86_FPU_INTERNAL_H */ diff --git a/arch/x86/include/asm/fpu/sched.h b/arch/x86/include/asm/fpu/sched.h new file mode 100644 index 0000000..99a8820 --- /dev/null +++ b/arch/x86/include/asm/fpu/sched.h @@ -0,0 +1,68 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_FPU_SCHED_H +#define _ASM_X86_FPU_SCHED_H + +#include + +#include +#include + +#include + +extern void save_fpregs_to_fpstate(struct fpu *fpu); +extern void fpu__drop(struct fpu *fpu); +extern int fpu_clone(struct task_struct *dst, unsigned long clone_flags); +extern void fpu_flush_thread(void); + +/* + * FPU state switching for scheduling. + * + * This is a two-stage process: + * + * - switch_fpu_prepare() saves the old state. + * This is done within the context of the old process. + * + * - switch_fpu_finish() sets TIF_NEED_FPU_LOAD; the floating point state + * will get loaded on return to userspace, or when the kernel needs it. + * + * If TIF_NEED_FPU_LOAD is cleared then the CPU's FPU registers + * are saved in the current thread's FPU register state. + * + * If TIF_NEED_FPU_LOAD is set then CPU's FPU registers may not + * hold current()'s FPU registers. It is required to load the + * registers before returning to userland or using the content + * otherwise. + * + * The FPU context is only stored/restored for a user task and + * PF_KTHREAD is used to distinguish between kernel and user threads. + */ +static inline void switch_fpu_prepare(struct fpu *old_fpu, int cpu) +{ + if (cpu_feature_enabled(X86_FEATURE_FPU) && + !(current->flags & PF_KTHREAD)) { + save_fpregs_to_fpstate(old_fpu); + /* + * The save operation preserved register state, so the + * fpu_fpregs_owner_ctx is still @old_fpu. Store the + * current CPU number in @old_fpu, so the next return + * to user space can avoid the FPU register restore + * when is returns on the same CPU and still owns the + * context. + */ + old_fpu->last_cpu = cpu; + + trace_x86_fpu_regs_deactivated(old_fpu); + } +} + +/* + * Delay loading of the complete FPU state until the return to userland. + * PKRU is handled separately. + */ +static inline void switch_fpu_finish(void) +{ + if (cpu_feature_enabled(X86_FEATURE_FPU)) + set_thread_flag(TIF_NEED_FPU_LOAD); +} + +#endif /* _ASM_X86_FPU_SCHED_H */ diff --git a/arch/x86/include/asm/fpu/signal.h b/arch/x86/include/asm/fpu/signal.h index 8b6631d..22b0273 100644 --- a/arch/x86/include/asm/fpu/signal.h +++ b/arch/x86/include/asm/fpu/signal.h @@ -5,6 +5,11 @@ #ifndef _ASM_X86_FPU_SIGNAL_H #define _ASM_X86_FPU_SIGNAL_H +#include +#include + +#include + #ifdef CONFIG_X86_64 # include # include @@ -31,6 +36,12 @@ fpu__alloc_mathframe(unsigned long sp, int ia32_frame, unsigned long fpu__get_fpstate_size(void); -extern void fpu__init_prepare_fx_sw_frame(void); +extern bool copy_fpstate_to_sigframe(void __user *buf, void __user *fp, int size); +extern void fpu__clear_user_states(struct fpu *fpu); +extern bool fpu__restore_sig(void __user *buf, int ia32_frame); + +extern void restore_fpregs_from_fpstate(struct fpstate *fpstate, u64 mask); + +extern bool copy_fpstate_to_sigframe(void __user *buf, void __user *fp, int size); #endif /* _ASM_X86_FPU_SIGNAL_H */ diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h index f5a38a5..3c06c82 100644 --- a/arch/x86/include/asm/fpu/types.h +++ b/arch/x86/include/asm/fpu/types.h @@ -120,6 +120,9 @@ enum xfeature { XFEATURE_RSRVD_COMP_13, XFEATURE_RSRVD_COMP_14, XFEATURE_LBR, + XFEATURE_RSRVD_COMP_16, + XFEATURE_XTILE_CFG, + XFEATURE_XTILE_DATA, XFEATURE_MAX, }; @@ -136,12 +139,21 @@ enum xfeature { #define XFEATURE_MASK_PKRU (1 << XFEATURE_PKRU) #define XFEATURE_MASK_PASID (1 << XFEATURE_PASID) #define XFEATURE_MASK_LBR (1 << XFEATURE_LBR) +#define XFEATURE_MASK_XTILE_CFG (1 << XFEATURE_XTILE_CFG) +#define XFEATURE_MASK_XTILE_DATA (1 << XFEATURE_XTILE_DATA) #define XFEATURE_MASK_FPSSE (XFEATURE_MASK_FP | XFEATURE_MASK_SSE) #define XFEATURE_MASK_AVX512 (XFEATURE_MASK_OPMASK \ | XFEATURE_MASK_ZMM_Hi256 \ | XFEATURE_MASK_Hi16_ZMM) +#ifdef CONFIG_X86_64 +# define XFEATURE_MASK_XTILE (XFEATURE_MASK_XTILE_DATA \ + | XFEATURE_MASK_XTILE_CFG) +#else +# define XFEATURE_MASK_XTILE (0) +#endif + #define FIRST_EXTENDED_XFEATURE XFEATURE_YMM struct reg_128_bit { @@ -153,6 +165,9 @@ struct reg_256_bit { struct reg_512_bit { u8 regbytes[512/8]; }; +struct reg_1024_byte { + u8 regbytes[1024]; +}; /* * State component 2: @@ -255,6 +270,23 @@ struct arch_lbr_state { u64 ler_to; u64 ler_info; struct lbr_entry entries[]; +}; + +/* + * State component 17: 64-byte tile configuration register. + */ +struct xtile_cfg { + u64 tcfg[8]; +} __packed; + +/* + * State component 18: 1KB tile data register. + * Each register represents 16 64-byte rows of the matrix + * data. But the number of registers depends on the actual + * implementation. + */ +struct xtile_data { + struct reg_1024_byte tmm; } __packed; /* @@ -309,6 +341,91 @@ union fpregs_state { u8 __padding[PAGE_SIZE]; }; +struct fpstate { + /* @kernel_size: The size of the kernel register image */ + unsigned int size; + + /* @user_size: The size in non-compacted UABI format */ + unsigned int user_size; + + /* @xfeatures: xfeatures for which the storage is sized */ + u64 xfeatures; + + /* @user_xfeatures: xfeatures valid in UABI buffers */ + u64 user_xfeatures; + + /* @xfd: xfeatures disabled to trap userspace use. */ + u64 xfd; + + /* @is_valloc: Indicator for dynamically allocated state */ + unsigned int is_valloc : 1; + + /* @is_guest: Indicator for guest state (KVM) */ + unsigned int is_guest : 1; + + /* + * @is_confidential: Indicator for KVM confidential mode. + * The FPU registers are restored by the + * vmentry firmware from encrypted guest + * memory. On vmexit the FPU registers are + * saved by firmware to encrypted guest memory + * and the registers are scrubbed before + * returning to the host. So there is no + * content which is worth saving and restoring. + * The fpstate has to be there so that + * preemption and softirq FPU usage works + * without special casing. + */ + unsigned int is_confidential : 1; + + /* @in_use: State is in use */ + unsigned int in_use : 1; + + /* @regs: The register state union for all supported formats */ + union fpregs_state regs; + + /* @regs is dynamically sized! Don't add anything after @regs! */ +} __aligned(64); + +struct fpu_state_perm { + /* + * @__state_perm: + * + * This bitmap indicates the permission for state components, which + * are available to a thread group. The permission prctl() sets the + * enabled state bits in thread_group_leader()->thread.fpu. + * + * All run time operations use the per thread information in the + * currently active fpu.fpstate which contains the xfeature masks + * and sizes for kernel and user space. + * + * This master permission field is only to be used when + * task.fpu.fpstate based checks fail to validate whether the task + * is allowed to expand it's xfeatures set which requires to + * allocate a larger sized fpstate buffer. + * + * Do not access this field directly. Use the provided helper + * function. Unlocked access is possible for quick checks. + */ + u64 __state_perm; + + /* + * @__state_size: + * + * The size required for @__state_perm. Only valid to access + * with sighand locked. + */ + unsigned int __state_size; + + /* + * @__user_state_size: + * + * The size required for @__state_perm user part. Only valid to + * access with sighand locked. + */ + unsigned int __user_state_size; +}; + /* * Highest level per task FPU state data structure that * contains the FPU register state plus various FPU @@ -337,19 +454,100 @@ struct fpu { unsigned long avx512_timestamp; /* - * @state: + * @fpstate: + * + * Pointer to the active struct fpstate. Initialized to + * point at @__fpstate below. + */ + struct fpstate *fpstate; + + /* + * @__task_fpstate: + * + * Pointer to an inactive struct fpstate. Initialized to NULL. Is + * used only for KVM support to swap out the regular task fpstate. + */ + struct fpstate *__task_fpstate; + + /* + * @perm: + * + * Permission related information + */ + struct fpu_state_perm perm; + + /* + * @__fpstate: * - * In-memory copy of all FPU registers that we save/restore - * over context switches. If the task is using the FPU then - * the registers in the FPU are more recent than this state - * copy. If the task context-switches away then they get - * saved here and represent the FPU state. + * Initial in-memory storage for FPU registers which are saved in + * context switch and when the kernel uses the FPU. The registers + * are restored from this storage on return to user space if they + * are not longer containing the tasks FPU register state. */ - union fpregs_state state; + struct fpstate __fpstate; /* - * WARNING: 'state' is dynamically-sized. Do not put + * WARNING: '__fpstate' is dynamically-sized. Do not put * anything after it here. */ }; +/* + * Guest pseudo FPU container + */ +struct fpu_guest { + /* + * @fpstate: Pointer to the allocated guest fpstate + */ + struct fpstate *fpstate; +}; + +/* + * FPU state configuration data. Initialized at boot time. Read only after init. + */ +struct fpu_state_config { + /* + * @max_size: + * + * The maximum size of the register state buffer. Includes all + * supported features except independent managed features. + */ + unsigned int max_size; + + /* + * @default_size: + * + * The default size of the register state buffer. Includes all + * supported features except independent managed features and + * features which have to be requested by user space before usage. + */ + unsigned int default_size; + + /* + * @max_features: + * + * The maximum supported features bitmap. Does not include + * independent managed features. + */ + u64 max_features; + + /* + * @default_features: + * + * The default supported features bitmap. Does not include + * independent managed features and features which have to + * be requested by user space before usage. + */ + u64 default_features; + /* + * @legacy_features: + * + * Features which can be reported back to user space + * even without XSAVE support, i.e. legacy features FP + SSE + */ + u64 legacy_features; +}; + +/* FPU state configuration information */ +extern struct fpu_state_config fpu_kernel_cfg, fpu_user_cfg; + #endif /* _ASM_X86_FPU_H */ diff --git a/arch/x86/include/asm/fpu/xcr.h b/arch/x86/include/asm/fpu/xcr.h index 1c7ab8d..79f95d3 100644 --- a/arch/x86/include/asm/fpu/xcr.h +++ b/arch/x86/include/asm/fpu/xcr.h @@ -2,17 +2,6 @@ #ifndef _ASM_X86_FPU_XCR_H #define _ASM_X86_FPU_XCR_H -/* - * MXCSR and XCR definitions: - */ - -static inline void ldmxcsr(u32 mxcsr) -{ - asm volatile("ldmxcsr %0" :: "m" (mxcsr)); -} - -extern unsigned int mxcsr_feature_mask; - #define XCR_XFEATURE_ENABLED_MASK 0x00000000 static inline u64 xgetbv(u32 index) diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index 109dfcc..0f8b90a 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -14,6 +14,8 @@ #define XSTATE_CPUID 0x0000000d +#define TILE_CPUID 0x0000001d + #define FXSAVE_SIZE 512 #define XSAVE_HDR_SIZE 64 @@ -33,7 +35,8 @@ XFEATURE_MASK_Hi16_ZMM | \ XFEATURE_MASK_PKRU | \ XFEATURE_MASK_BNDREGS | \ - XFEATURE_MASK_BNDCSR) + XFEATURE_MASK_BNDCSR | \ + XFEATURE_MASK_XTILE) /* * Features which are restored when returning to user space. @@ -43,6 +46,9 @@ #define XFEATURE_MASK_USER_RESTORE \ (XFEATURE_MASK_USER_SUPPORTED & ~XFEATURE_MASK_PKRU) +/* Features which are dynamically enabled for a process on request */ +#define XFEATURE_MASK_USER_DYNAMIC XFEATURE_MASK_XTILE_DATA + /* All currently supported supervisor features */ #define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID) @@ -78,78 +84,42 @@ XFEATURE_MASK_INDEPENDENT | \ XFEATURE_MASK_SUPERVISOR_UNSUPPORTED) -#ifdef CONFIG_X86_64 -#define REX_PREFIX "0x48, " -#else -#define REX_PREFIX -#endif - -extern u64 xfeatures_mask_all; - -static inline u64 xfeatures_mask_supervisor(void) -{ - return xfeatures_mask_all & XFEATURE_MASK_SUPERVISOR_SUPPORTED; -} - /* - * The xfeatures which are enabled in XCR0 and expected to be in ptrace - * buffers and signal frames. + * The feature mask required to restore FPU state: + * - All user states which are not eagerly switched in switch_to()/exec() + * - The suporvisor states */ -static inline u64 xfeatures_mask_uabi(void) -{ - return xfeatures_mask_all & XFEATURE_MASK_USER_SUPPORTED; -} - -/* - * The xfeatures which are restored by the kernel when returning to user - * mode. This is not necessarily the same as xfeatures_mask_uabi() as the - * kernel does not manage all XCR0 enabled features via xsave/xrstor as - * some of them have to be switched eagerly on context switch and exec(). - */ -static inline u64 xfeatures_mask_restore_user(void) -{ - return xfeatures_mask_all & XFEATURE_MASK_USER_RESTORE; -} - -/* - * Like xfeatures_mask_restore_user() but additionally restors the - * supported supervisor states. - */ -static inline u64 xfeatures_mask_fpstate(void) -{ - return xfeatures_mask_all & \ - (XFEATURE_MASK_USER_RESTORE | XFEATURE_MASK_SUPERVISOR_SUPPORTED); -} - -static inline u64 xfeatures_mask_independent(void) -{ - if (!boot_cpu_has(X86_FEATURE_ARCH_LBR)) - return XFEATURE_MASK_INDEPENDENT & ~XFEATURE_MASK_LBR; - - return XFEATURE_MASK_INDEPENDENT; -} +#define XFEATURE_MASK_FPSTATE (XFEATURE_MASK_USER_RESTORE | \ + XFEATURE_MASK_SUPERVISOR_SUPPORTED) extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS]; extern void __init update_regset_xstate_info(unsigned int size, u64 xstate_mask); -void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr); int xfeature_size(int xfeature_nr); -int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf); -int copy_sigframe_from_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf); void xsaves(struct xregs_state *xsave, u64 mask); void xrstors(struct xregs_state *xsave, u64 mask); -enum xstate_copy_mode { - XSTATE_COPY_FP, - XSTATE_COPY_FX, - XSTATE_COPY_XSAVE, -}; +int xfd_enable_feature(u64 xfd_err); + +#ifdef CONFIG_X86_64 +DECLARE_STATIC_KEY_FALSE(__fpu_state_size_dynamic); +#endif + +#ifdef CONFIG_X86_64 +DECLARE_STATIC_KEY_FALSE(__fpu_state_size_dynamic); -struct membuf; -void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk, - enum xstate_copy_mode mode); +static __always_inline __pure bool fpu_state_size_dynamic(void) +{ + return static_branch_unlikely(&__fpu_state_size_dynamic); +} +#else +static __always_inline __pure bool fpu_state_size_dynamic(void) +{ + return false; +} +#endif #endif diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 13f6465..32f300d 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -691,11 +691,10 @@ struct kvm_vcpu_arch { * * Note that while the PKRU state lives inside the fpu registers, * it is switched out separately at VMENTER and VMEXIT time. The - * "guest_fpu" state here contains the guest FPU context, with the + * "guest_fpstate" state here contains the guest FPU context, with the * host PRKU bits. */ - struct fpu *user_fpu; - struct fpu *guest_fpu; + struct fpu_guest guest_fpu; u64 xcr0; u64 guest_supported_xcr0; @@ -1686,8 +1685,6 @@ void kvm_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector); int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int idt_index, int reason, bool has_error_code, u32 error_code); -void kvm_free_guest_fpu(struct kvm_vcpu *vcpu); - void kvm_post_set_cr0(struct kvm_vcpu *vcpu, unsigned long old_cr0, unsigned long cr0); void kvm_post_set_cr4(struct kvm_vcpu *vcpu, unsigned long old_cr4, unsigned long cr4); int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0); diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index a7c4134..01e2650 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -625,6 +625,8 @@ #define MSR_IA32_BNDCFGS_RSVD 0x00000ffc +#define MSR_IA32_XFD 0x000001c4 +#define MSR_IA32_XFD_ERR 0x000001c5 #define MSR_IA32_XSS 0x00000da0 #define MSR_IA32_APICBASE 0x0000001b diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h index a3f87f1..6b52182 100644 --- a/arch/x86/include/asm/msr.h +++ b/arch/x86/include/asm/msr.h @@ -92,7 +92,7 @@ static __always_inline unsigned long long __rdmsr(unsigned int msr) asm volatile("1: rdmsr\n" "2:\n" - _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_rdmsr_unsafe) + _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_RDMSR) : EAX_EDX_RET(val, low, high) : "c" (msr)); return EAX_EDX_VAL(val, low, high); @@ -102,7 +102,7 @@ static __always_inline void __wrmsr(unsigned int msr, u32 low, u32 high) { asm volatile("1: wrmsr\n" "2:\n" - _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_wrmsr_unsafe) + _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_WRMSR) : : "c" (msr), "a"(low), "d" (high) : "memory"); } diff --git a/arch/x86/include/asm/pkru.h b/arch/x86/include/asm/pkru.h index ccc539f..4cd49af 100644 --- a/arch/x86/include/asm/pkru.h +++ b/arch/x86/include/asm/pkru.h @@ -2,7 +2,7 @@ #ifndef _ASM_X86_PKRU_H #define _ASM_X86_PKRU_H -#include +#include #define PKRU_AD_BIT 0x1 #define PKRU_WD_BIT 0x2 diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index e81177e..f97aa49 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -461,9 +461,6 @@ DECLARE_PER_CPU(struct irq_stack *, hardirq_stack_ptr); DECLARE_PER_CPU(struct irq_stack *, softirq_stack_ptr); #endif /* !X86_64 */ -extern unsigned int fpu_kernel_xstate_size; -extern unsigned int fpu_user_xstate_size; - struct perf_event; struct thread_struct { @@ -537,12 +534,12 @@ struct thread_struct { */ }; -/* Whitelist the FPU state from the task_struct for hardened usercopy. */ +extern void fpu_thread_struct_whitelist(unsigned long *offset, unsigned long *size); + static inline void arch_thread_struct_whitelist(unsigned long *offset, unsigned long *size) { - *offset = offsetof(struct thread_struct, fpu.state); - *size = fpu_kernel_xstate_size; + fpu_thread_struct_whitelist(offset, size); } static inline void diff --git a/arch/x86/include/asm/proto.h b/arch/x86/include/asm/proto.h index 8c5d191..feed36d 100644 --- a/arch/x86/include/asm/proto.h +++ b/arch/x86/include/asm/proto.h @@ -40,6 +40,6 @@ void x86_report_nx(void); extern int reboot_force; long do_arch_prctl_common(struct task_struct *task, int option, - unsigned long cpuid_enabled); + unsigned long arg2); #endif /* _ASM_X86_PROTO_H */ diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h index 7204402..8dd8e8e 100644 --- a/arch/x86/include/asm/segment.h +++ b/arch/x86/include/asm/segment.h @@ -339,7 +339,7 @@ static inline void __loadsegment_fs(unsigned short value) "1: movw %0, %%fs \n" "2: \n" - _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_clear_fs) + _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_CLEAR_FS) : : "rm" (value) : "memory"); } diff --git a/arch/x86/include/asm/trace/fpu.h b/arch/x86/include/asm/trace/fpu.h index 879b777..4645a63 100644 --- a/arch/x86/include/asm/trace/fpu.h +++ b/arch/x86/include/asm/trace/fpu.h @@ -22,8 +22,8 @@ DECLARE_EVENT_CLASS(x86_fpu, __entry->fpu = fpu; __entry->load_fpu = test_thread_flag(TIF_NEED_FPU_LOAD); if (boot_cpu_has(X86_FEATURE_OSXSAVE)) { - __entry->xfeatures = fpu->state.xsave.header.xfeatures; - __entry->xcomp_bv = fpu->state.xsave.header.xcomp_bv; + __entry->xfeatures = fpu->fpstate->regs.xsave.header.xfeatures; + __entry->xcomp_bv = fpu->fpstate->regs.xsave.header.xcomp_bv; } ), TP_printk("x86/fpu: %p load: %d xfeatures: %llx xcomp_bv: %llx", diff --git a/arch/x86/include/uapi/asm/prctl.h b/arch/x86/include/uapi/asm/prctl.h index 5a6aac9..754a078 100644 --- a/arch/x86/include/uapi/asm/prctl.h +++ b/arch/x86/include/uapi/asm/prctl.h @@ -10,6 +10,10 @@ #define ARCH_GET_CPUID 0x1011 #define ARCH_SET_CPUID 0x1012 +#define ARCH_GET_XCOMP_SUPP 0x1021 +#define ARCH_GET_XCOMP_PERM 0x1022 +#define ARCH_REQ_XCOMP_PERM 0x1023 + #define ARCH_MAP_VDSO_X32 0x2001 #define ARCH_MAP_VDSO_32 0x2002 #define ARCH_MAP_VDSO_64 0x2003 diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index ba43597..31e2412 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -22,7 +22,7 @@ #include #include #include -#include +#include #include #include #include diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 8be4b08..8ed18d0 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -42,7 +42,7 @@ #include #include #include -#include +#include #include #include #include diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c index defda61..cb2fdd1 100644 --- a/arch/x86/kernel/cpu/cpuid-deps.c +++ b/arch/x86/kernel/cpu/cpuid-deps.c @@ -75,6 +75,8 @@ static const struct cpuid_dep cpuid_deps[] = { { X86_FEATURE_SGX_LC, X86_FEATURE_SGX }, { X86_FEATURE_SGX1, X86_FEATURE_SGX }, { X86_FEATURE_SGX2, X86_FEATURE_SGX1 }, + { X86_FEATURE_XFD, X86_FEATURE_XSAVES }, + { X86_FEATURE_AMX_TILE, X86_FEATURE_XFD }, {} }; diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 193204a..2af4b42 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -373,13 +373,16 @@ static int msr_to_offset(u32 msr) return -1; } -__visible bool ex_handler_rdmsr_fault(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr, - unsigned long error_code, - unsigned long fault_addr) +void ex_handler_msr_mce(struct pt_regs *regs, bool wrmsr) { - pr_emerg("MSR access error: RDMSR from 0x%x at rIP: 0x%lx (%pS)\n", - (unsigned int)regs->cx, regs->ip, (void *)regs->ip); + if (wrmsr) { + pr_emerg("MSR access error: WRMSR to 0x%x (tried to write 0x%08x%08x) at rIP: 0x%lx (%pS)\n", + (unsigned int)regs->cx, (unsigned int)regs->dx, (unsigned int)regs->ax, + regs->ip, (void *)regs->ip); + } else { + pr_emerg("MSR access error: RDMSR from 0x%x at rIP: 0x%lx (%pS)\n", + (unsigned int)regs->cx, regs->ip, (void *)regs->ip); + } show_stack_regs(regs); @@ -387,8 +390,6 @@ __visible bool ex_handler_rdmsr_fault(const struct exception_table_entry *fixup, while (true) cpu_relax(); - - return true; } /* MSR access wrappers used for error injection */ @@ -420,32 +421,13 @@ static noinstr u64 mce_rdmsrl(u32 msr) */ asm volatile("1: rdmsr\n" "2:\n" - _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_rdmsr_fault) + _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_RDMSR_IN_MCE) : EAX_EDX_RET(val, low, high) : "c" (msr)); return EAX_EDX_VAL(val, low, high); } -__visible bool ex_handler_wrmsr_fault(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr, - unsigned long error_code, - unsigned long fault_addr) -{ - pr_emerg("MSR access error: WRMSR to 0x%x (tried to write 0x%08x%08x) at rIP: 0x%lx (%pS)\n", - (unsigned int)regs->cx, (unsigned int)regs->dx, (unsigned int)regs->ax, - regs->ip, (void *)regs->ip); - - show_stack_regs(regs); - - panic("MCA architectural violation!\n"); - - while (true) - cpu_relax(); - - return true; -} - static noinstr void mce_wrmsrl(u32 msr, u64 v) { u32 low, high; @@ -470,7 +452,7 @@ static noinstr void mce_wrmsrl(u32 msr, u64 v) /* See comment in mce_rdmsrl() */ asm volatile("1: wrmsr\n" "2:\n" - _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_wrmsr_fault) + _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_WRMSR_IN_MCE) : : "c" (msr), "a"(low), "d" (high) : "memory"); } diff --git a/arch/x86/kernel/cpu/mce/internal.h b/arch/x86/kernel/cpu/mce/internal.h index 88dcc79..3463f8c 100644 --- a/arch/x86/kernel/cpu/mce/internal.h +++ b/arch/x86/kernel/cpu/mce/internal.h @@ -61,7 +61,7 @@ static inline void cmci_disable_bank(int bank) { } static inline void intel_init_cmci(void) { } static inline void intel_init_lmce(void) { } static inline void intel_clear_lmce(void) { } -static inline bool intel_filter_mce(struct mce *m) { return false; }; +static inline bool intel_filter_mce(struct mce *m) { return false; } #endif void mce_timer_kick(unsigned long interval); @@ -183,17 +183,7 @@ extern bool filter_mce(struct mce *m); #ifdef CONFIG_X86_MCE_AMD extern bool amd_filter_mce(struct mce *m); #else -static inline bool amd_filter_mce(struct mce *m) { return false; }; +static inline bool amd_filter_mce(struct mce *m) { return false; } #endif -__visible bool ex_handler_rdmsr_fault(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr, - unsigned long error_code, - unsigned long fault_addr); - -__visible bool ex_handler_wrmsr_fault(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr, - unsigned long error_code, - unsigned long fault_addr); - #endif /* __X86_MCE_INTERNAL_H__ */ diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c index 17e6314..f60bbaf 100644 --- a/arch/x86/kernel/cpu/mce/severity.c +++ b/arch/x86/kernel/cpu/mce/severity.c @@ -265,25 +265,25 @@ static bool is_copy_from_user(struct pt_regs *regs) */ static int error_context(struct mce *m, struct pt_regs *regs) { - enum handler_type t; - if ((m->cs & 3) == 3) return IN_USER; if (!mc_recoverable(m->mcgstatus)) return IN_KERNEL; - t = ex_get_fault_handler_type(m->ip); - if (t == EX_HANDLER_FAULT) { - m->kflags |= MCE_IN_KERNEL_RECOV; - return IN_KERNEL_RECOV; - } - if (t == EX_HANDLER_UACCESS && regs && is_copy_from_user(regs)) { - m->kflags |= MCE_IN_KERNEL_RECOV; + switch (ex_get_fixup_type(m->ip)) { + case EX_TYPE_UACCESS: + case EX_TYPE_COPY: + if (!regs || !is_copy_from_user(regs)) + return IN_KERNEL; m->kflags |= MCE_IN_KERNEL_COPYIN; + fallthrough; + case EX_TYPE_FAULT_MCE_SAFE: + case EX_TYPE_DEFAULT_MCE_SAFE: + m->kflags |= MCE_IN_KERNEL_RECOV; return IN_KERNEL_RECOV; + default: + return IN_KERNEL; } - - return IN_KERNEL; } static int mce_severity_amd_smca(struct mce *m, enum context err_ctx) diff --git a/arch/x86/kernel/fpu/bugs.c b/arch/x86/kernel/fpu/bugs.c index 2954fab..794e701 100644 --- a/arch/x86/kernel/fpu/bugs.c +++ b/arch/x86/kernel/fpu/bugs.c @@ -2,7 +2,7 @@ /* * x86 FPU bug checks: */ -#include +#include /* * Boot time CPU/FPU FDIV bug detection code: diff --git a/arch/x86/kernel/fpu/context.h b/arch/x86/kernel/fpu/context.h new file mode 100644 index 0000000..958accf --- /dev/null +++ b/arch/x86/kernel/fpu/context.h @@ -0,0 +1,83 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __X86_KERNEL_FPU_CONTEXT_H +#define __X86_KERNEL_FPU_CONTEXT_H + +#include +#include + +/* Functions related to FPU context tracking */ + +/* + * The in-register FPU state for an FPU context on a CPU is assumed to be + * valid if the fpu->last_cpu matches the CPU, and the fpu_fpregs_owner_ctx + * matches the FPU. + * + * If the FPU register state is valid, the kernel can skip restoring the + * FPU state from memory. + * + * Any code that clobbers the FPU registers or updates the in-memory + * FPU state for a task MUST let the rest of the kernel know that the + * FPU registers are no longer valid for this task. + * + * Either one of these invalidation functions is enough. Invalidate + * a resource you control: CPU if using the CPU for something else + * (with preemption disabled), FPU for the current task, or a task that + * is prevented from running by the current task. + */ +static inline void __cpu_invalidate_fpregs_state(void) +{ + __this_cpu_write(fpu_fpregs_owner_ctx, NULL); +} + +static inline void __fpu_invalidate_fpregs_state(struct fpu *fpu) +{ + fpu->last_cpu = -1; +} + +static inline int fpregs_state_valid(struct fpu *fpu, unsigned int cpu) +{ + return fpu == this_cpu_read(fpu_fpregs_owner_ctx) && cpu == fpu->last_cpu; +} + +static inline void fpregs_deactivate(struct fpu *fpu) +{ + __this_cpu_write(fpu_fpregs_owner_ctx, NULL); + trace_x86_fpu_regs_deactivated(fpu); +} + +static inline void fpregs_activate(struct fpu *fpu) +{ + __this_cpu_write(fpu_fpregs_owner_ctx, fpu); + trace_x86_fpu_regs_activated(fpu); +} + +/* Internal helper for switch_fpu_return() and signal frame setup */ +static inline void fpregs_restore_userregs(void) +{ + struct fpu *fpu = ¤t->thread.fpu; + int cpu = smp_processor_id(); + + if (WARN_ON_ONCE(current->flags & PF_KTHREAD)) + return; + + if (!fpregs_state_valid(fpu, cpu)) { + /* + * This restores _all_ xstate which has not been + * established yet. + * + * If PKRU is enabled, then the PKRU value is already + * correct because it was either set in switch_to() or in + * flush_thread(). So it is excluded because it might be + * not up to date in current->thread.fpu.xsave state. + * + * XFD state is handled in restore_fpregs_from_fpstate(). + */ + restore_fpregs_from_fpstate(fpu->fpstate, XFEATURE_MASK_FPSTATE); + + fpregs_activate(fpu); + fpu->last_cpu = cpu; + } + clear_thread_flag(TIF_NEED_FPU_LOAD); +} + +#endif diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 7ada7bd..8ea306b 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -6,8 +6,9 @@ * General FPU state handling cleanups * Gareth Hughes , May 2000 */ -#include +#include #include +#include #include #include #include @@ -15,15 +16,30 @@ #include #include +#include + +#include "context.h" +#include "internal.h" +#include "legacy.h" +#include "xstate.h" #define CREATE_TRACE_POINTS #include +#ifdef CONFIG_X86_64 +DEFINE_STATIC_KEY_FALSE(__fpu_state_size_dynamic); +DEFINE_PER_CPU(u64, xfd_state); +#endif + +/* The FPU state configuration data for kernel and user space */ +struct fpu_state_config fpu_kernel_cfg __ro_after_init; +struct fpu_state_config fpu_user_cfg __ro_after_init; + /* * Represents the initial FPU state. It's mostly (but not completely) zeroes, * depending on the FPU hardware format: */ -union fpregs_state init_fpstate __ro_after_init; +struct fpstate init_fpstate __ro_after_init; /* * Track whether the kernel is using the FPU state @@ -83,7 +99,7 @@ bool irq_fpu_usable(void) EXPORT_SYMBOL(irq_fpu_usable); /* - * Save the FPU register state in fpu->state. The register state is + * Save the FPU register state in fpu->fpstate->regs. The register state is * preserved. * * Must be called with fpregs_lock() held. @@ -99,19 +115,19 @@ EXPORT_SYMBOL(irq_fpu_usable); void save_fpregs_to_fpstate(struct fpu *fpu) { if (likely(use_xsave())) { - os_xsave(&fpu->state.xsave); + os_xsave(fpu->fpstate); /* * AVX512 state is tracked here because its use is * known to slow the max clock speed of the core. */ - if (fpu->state.xsave.header.xfeatures & XFEATURE_MASK_AVX512) + if (fpu->fpstate->regs.xsave.header.xfeatures & XFEATURE_MASK_AVX512) fpu->avx512_timestamp = jiffies; return; } if (likely(use_fxsr())) { - fxsave(&fpu->state.fxsave); + fxsave(&fpu->fpstate->regs.fxsave); return; } @@ -119,12 +135,11 @@ void save_fpregs_to_fpstate(struct fpu *fpu) * Legacy FPU register saving, FNSAVE always clears FPU registers, * so we have to reload them from the memory state. */ - asm volatile("fnsave %[fp]; fwait" : [fp] "=m" (fpu->state.fsave)); - frstor(&fpu->state.fsave); + asm volatile("fnsave %[fp]; fwait" : [fp] "=m" (fpu->fpstate->regs.fsave)); + frstor(&fpu->fpstate->regs.fsave); } -EXPORT_SYMBOL(save_fpregs_to_fpstate); -void __restore_fpregs_from_fpstate(union fpregs_state *fpstate, u64 mask) +void restore_fpregs_from_fpstate(struct fpstate *fpstate, u64 mask) { /* * AMD K7/K8 and later CPUs up to Zen don't save/restore @@ -141,15 +156,181 @@ void __restore_fpregs_from_fpstate(union fpregs_state *fpstate, u64 mask) } if (use_xsave()) { - os_xrstor(&fpstate->xsave, mask); + /* + * Dynamically enabled features are enabled in XCR0, but + * usage requires also that the corresponding bits in XFD + * are cleared. If the bits are set then using a related + * instruction will raise #NM. This allows to do the + * allocation of the larger FPU buffer lazy from #NM or if + * the task has no permission to kill it which would happen + * via #UD if the feature is disabled in XCR0. + * + * XFD state is following the same life time rules as + * XSTATE and to restore state correctly XFD has to be + * updated before XRSTORS otherwise the component would + * stay in or go into init state even if the bits are set + * in fpstate::regs::xsave::xfeatures. + */ + xfd_update_state(fpstate); + + /* + * Restoring state always needs to modify all features + * which are in @mask even if the current task cannot use + * extended features. + * + * So fpstate->xfeatures cannot be used here, because then + * a feature for which the task has no permission but was + * used by the previous task would not go into init state. + */ + mask = fpu_kernel_cfg.max_features & mask; + + os_xrstor(fpstate, mask); } else { if (use_fxsr()) - fxrstor(&fpstate->fxsave); + fxrstor(&fpstate->regs.fxsave); else - frstor(&fpstate->fsave); + frstor(&fpstate->regs.fsave); } } -EXPORT_SYMBOL_GPL(__restore_fpregs_from_fpstate); + +void fpu_reset_from_exception_fixup(void) +{ + restore_fpregs_from_fpstate(&init_fpstate, XFEATURE_MASK_FPSTATE); +} + +#if IS_ENABLED(CONFIG_KVM) +static void __fpstate_reset(struct fpstate *fpstate); + +bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu) +{ + struct fpstate *fpstate; + unsigned int size; + + size = fpu_user_cfg.default_size + ALIGN(offsetof(struct fpstate, regs), 64); + fpstate = vzalloc(size); + if (!fpstate) + return false; + + __fpstate_reset(fpstate); + fpstate_init_user(fpstate); + fpstate->is_valloc = true; + fpstate->is_guest = true; + + gfpu->fpstate = fpstate; + return true; +} +EXPORT_SYMBOL_GPL(fpu_alloc_guest_fpstate); + +void fpu_free_guest_fpstate(struct fpu_guest *gfpu) +{ + struct fpstate *fps = gfpu->fpstate; + + if (!fps) + return; + + if (WARN_ON_ONCE(!fps->is_valloc || !fps->is_guest || fps->in_use)) + return; + + gfpu->fpstate = NULL; + vfree(fps); +} +EXPORT_SYMBOL_GPL(fpu_free_guest_fpstate); + +int fpu_swap_kvm_fpstate(struct fpu_guest *guest_fpu, bool enter_guest) +{ + struct fpstate *guest_fps = guest_fpu->fpstate; + struct fpu *fpu = ¤t->thread.fpu; + struct fpstate *cur_fps = fpu->fpstate; + + fpregs_lock(); + if (!cur_fps->is_confidential && !test_thread_flag(TIF_NEED_FPU_LOAD)) + save_fpregs_to_fpstate(fpu); + + /* Swap fpstate */ + if (enter_guest) { + fpu->__task_fpstate = cur_fps; + fpu->fpstate = guest_fps; + guest_fps->in_use = true; + } else { + guest_fps->in_use = false; + fpu->fpstate = fpu->__task_fpstate; + fpu->__task_fpstate = NULL; + } + + cur_fps = fpu->fpstate; + + if (!cur_fps->is_confidential) { + /* Includes XFD update */ + restore_fpregs_from_fpstate(cur_fps, XFEATURE_MASK_FPSTATE); + } else { + /* + * XSTATE is restored by firmware from encrypted + * memory. Make sure XFD state is correct while + * running with guest fpstate + */ + xfd_update_state(cur_fps); + } + + fpregs_mark_activate(); + fpregs_unlock(); + return 0; +} +EXPORT_SYMBOL_GPL(fpu_swap_kvm_fpstate); + +void fpu_copy_guest_fpstate_to_uabi(struct fpu_guest *gfpu, void *buf, + unsigned int size, u32 pkru) +{ + struct fpstate *kstate = gfpu->fpstate; + union fpregs_state *ustate = buf; + struct membuf mb = { .p = buf, .left = size }; + + if (cpu_feature_enabled(X86_FEATURE_XSAVE)) { + __copy_xstate_to_uabi_buf(mb, kstate, pkru, XSTATE_COPY_XSAVE); + } else { + memcpy(&ustate->fxsave, &kstate->regs.fxsave, + sizeof(ustate->fxsave)); + /* Make it restorable on a XSAVE enabled host */ + ustate->xsave.header.xfeatures = XFEATURE_MASK_FPSSE; + } +} +EXPORT_SYMBOL_GPL(fpu_copy_guest_fpstate_to_uabi); + +int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, const void *buf, + u64 xcr0, u32 *vpkru) +{ + struct fpstate *kstate = gfpu->fpstate; + const union fpregs_state *ustate = buf; + struct pkru_state *xpkru; + int ret; + + if (!cpu_feature_enabled(X86_FEATURE_XSAVE)) { + if (ustate->xsave.header.xfeatures & ~XFEATURE_MASK_FPSSE) + return -EINVAL; + if (ustate->fxsave.mxcsr & ~mxcsr_feature_mask) + return -EINVAL; + memcpy(&kstate->regs.fxsave, &ustate->fxsave, sizeof(ustate->fxsave)); + return 0; + } + + if (ustate->xsave.header.xfeatures & ~xcr0) + return -EINVAL; + + ret = copy_uabi_from_kernel_to_xstate(kstate, ustate); + if (ret) + return ret; + + /* Retrieve PKRU if not in init state */ + if (kstate->regs.xsave.header.xfeatures & XFEATURE_MASK_PKRU) { + xpkru = get_xsave_addr(&kstate->regs.xsave, XFEATURE_PKRU); + *vpkru = xpkru->pkru; + } + + /* Ensure that XCOMP_BV is set up for XSAVES */ + xstate_init_xcomp_bv(&kstate->regs.xsave, kstate->xfeatures); + return 0; +} +EXPORT_SYMBOL_GPL(fpu_copy_uabi_to_guest_fpstate); +#endif /* CONFIG_KVM */ void kernel_fpu_begin_mask(unsigned int kfpu_mask) { @@ -203,52 +384,88 @@ void fpu_sync_fpstate(struct fpu *fpu) fpregs_unlock(); } -static inline void fpstate_init_xstate(struct xregs_state *xsave) +static inline unsigned int init_fpstate_copy_size(void) { - /* - * XRSTORS requires these bits set in xcomp_bv, or it will - * trigger #GP: - */ - xsave->header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT | xfeatures_mask_all; + if (!use_xsave()) + return fpu_kernel_cfg.default_size; + + /* XSAVE(S) just needs the legacy and the xstate header part */ + return sizeof(init_fpstate.regs.xsave); } -static inline void fpstate_init_fxstate(struct fxregs_state *fx) +static inline void fpstate_init_fxstate(struct fpstate *fpstate) { - fx->cwd = 0x37f; - fx->mxcsr = MXCSR_DEFAULT; + fpstate->regs.fxsave.cwd = 0x37f; + fpstate->regs.fxsave.mxcsr = MXCSR_DEFAULT; } /* * Legacy x87 fpstate state init: */ -static inline void fpstate_init_fstate(struct fregs_state *fp) +static inline void fpstate_init_fstate(struct fpstate *fpstate) { - fp->cwd = 0xffff037fu; - fp->swd = 0xffff0000u; - fp->twd = 0xffffffffu; - fp->fos = 0xffff0000u; + fpstate->regs.fsave.cwd = 0xffff037fu; + fpstate->regs.fsave.swd = 0xffff0000u; + fpstate->regs.fsave.twd = 0xffffffffu; + fpstate->regs.fsave.fos = 0xffff0000u; } -void fpstate_init(union fpregs_state *state) +/* + * Used in two places: + * 1) Early boot to setup init_fpstate for non XSAVE systems + * 2) fpu_init_fpstate_user() which is invoked from KVM + */ +void fpstate_init_user(struct fpstate *fpstate) { - if (!static_cpu_has(X86_FEATURE_FPU)) { - fpstate_init_soft(&state->soft); + if (!cpu_feature_enabled(X86_FEATURE_FPU)) { + fpstate_init_soft(&fpstate->regs.soft); return; } - memset(state, 0, fpu_kernel_xstate_size); + xstate_init_xcomp_bv(&fpstate->regs.xsave, fpstate->xfeatures); - if (static_cpu_has(X86_FEATURE_XSAVES)) - fpstate_init_xstate(&state->xsave); - if (static_cpu_has(X86_FEATURE_FXSR)) - fpstate_init_fxstate(&state->fxsave); + if (cpu_feature_enabled(X86_FEATURE_FXSR)) + fpstate_init_fxstate(fpstate); else - fpstate_init_fstate(&state->fsave); + fpstate_init_fstate(fpstate); +} + +static void __fpstate_reset(struct fpstate *fpstate) +{ + /* Initialize sizes and feature masks */ + fpstate->size = fpu_kernel_cfg.default_size; + fpstate->user_size = fpu_user_cfg.default_size; + fpstate->xfeatures = fpu_kernel_cfg.default_features; + fpstate->user_xfeatures = fpu_user_cfg.default_features; + fpstate->xfd = init_fpstate.xfd; +} + +void fpstate_reset(struct fpu *fpu) +{ + /* Set the fpstate pointer to the default fpstate */ + fpu->fpstate = &fpu->__fpstate; + __fpstate_reset(fpu->fpstate); + + /* Initialize the permission related info in fpu */ + fpu->perm.__state_perm = fpu_kernel_cfg.default_features; + fpu->perm.__state_size = fpu_kernel_cfg.default_size; + fpu->perm.__user_state_size = fpu_user_cfg.default_size; +} + +static inline void fpu_inherit_perms(struct fpu *dst_fpu) +{ + if (fpu_state_size_dynamic()) { + struct fpu *src_fpu = ¤t->group_leader->thread.fpu; + + spin_lock_irq(¤t->sighand->siglock); + /* Fork also inherits the permissions of the parent */ + dst_fpu->perm = src_fpu->perm; + spin_unlock_irq(¤t->sighand->siglock); + } } -EXPORT_SYMBOL_GPL(fpstate_init); /* Clone current's FPU state on fork */ -int fpu_clone(struct task_struct *dst) +int fpu_clone(struct task_struct *dst, unsigned long clone_flags) { struct fpu *src_fpu = ¤t->thread.fpu; struct fpu *dst_fpu = &dst->thread.fpu; @@ -256,30 +473,51 @@ int fpu_clone(struct task_struct *dst) /* The new task's FPU state cannot be valid in the hardware. */ dst_fpu->last_cpu = -1; + fpstate_reset(dst_fpu); + if (!cpu_feature_enabled(X86_FEATURE_FPU)) return 0; /* - * Don't let 'init optimized' areas of the XSAVE area - * leak into the child task: + * Enforce reload for user space tasks and prevent kernel threads + * from trying to save the FPU registers on context switch. + */ + set_tsk_thread_flag(dst, TIF_NEED_FPU_LOAD); + + /* + * No FPU state inheritance for kernel threads and IO + * worker threads. + */ + if (dst->flags & (PF_KTHREAD | PF_IO_WORKER)) { + /* Clear out the minimal state */ + memcpy(&dst_fpu->fpstate->regs, &init_fpstate.regs, + init_fpstate_copy_size()); + return 0; + } + + /* + * If a new feature is added, ensure all dynamic features are + * caller-saved from here! */ - memset(&dst_fpu->state.xsave, 0, fpu_kernel_xstate_size); + BUILD_BUG_ON(XFEATURE_MASK_USER_DYNAMIC != XFEATURE_MASK_XTILE_DATA); /* - * If the FPU registers are not owned by current just memcpy() the - * state. Otherwise save the FPU registers directly into the - * child's FPU context, without any memory-to-memory copying. + * Save the default portion of the current FPU state into the + * clone. Assume all dynamic features to be defined as caller- + * saved, which enables skipping both the expansion of fpstate + * and the copying of any dynamic state. + * + * Do not use memcpy() when TIF_NEED_FPU_LOAD is set because + * copying is not valid when current uses non-default states. */ fpregs_lock(); if (test_thread_flag(TIF_NEED_FPU_LOAD)) - memcpy(&dst_fpu->state, &src_fpu->state, fpu_kernel_xstate_size); - - else - save_fpregs_to_fpstate(dst_fpu); + fpregs_restore_userregs(); + save_fpregs_to_fpstate(dst_fpu); + if (!(clone_flags & CLONE_THREAD)) + fpu_inherit_perms(dst_fpu); fpregs_unlock(); - set_tsk_thread_flag(dst, TIF_NEED_FPU_LOAD); - trace_x86_fpu_copy_src(src_fpu); trace_x86_fpu_copy_dst(dst_fpu); @@ -287,6 +525,16 @@ int fpu_clone(struct task_struct *dst) } /* + * Whitelist the FPU register state embedded into task_struct for hardened + * usercopy. + */ +void fpu_thread_struct_whitelist(unsigned long *offset, unsigned long *size) +{ + *offset = offsetof(struct thread_struct, fpu.__fpstate.regs); + *size = fpu_kernel_cfg.default_size; +} + +/* * Drops current FPU state: deactivates the fpregs and * the fpstate. NOTE: it still leaves previous contents * in the fpregs in the eager-FPU case. @@ -319,28 +567,19 @@ void fpu__drop(struct fpu *fpu) static inline void restore_fpregs_from_init_fpstate(u64 features_mask) { if (use_xsave()) - os_xrstor(&init_fpstate.xsave, features_mask); + os_xrstor(&init_fpstate, features_mask); else if (use_fxsr()) - fxrstor(&init_fpstate.fxsave); + fxrstor(&init_fpstate.regs.fxsave); else - frstor(&init_fpstate.fsave); + frstor(&init_fpstate.regs.fsave); pkru_write_default(); } -static inline unsigned int init_fpstate_copy_size(void) -{ - if (!use_xsave()) - return fpu_kernel_xstate_size; - - /* XSAVE(S) just needs the legacy and the xstate header part */ - return sizeof(init_fpstate.xsave); -} - /* * Reset current->fpu memory state to the init values. */ -static void fpu_reset_fpstate(void) +static void fpu_reset_fpregs(void) { struct fpu *fpu = ¤t->thread.fpu; @@ -359,7 +598,7 @@ static void fpu_reset_fpstate(void) * user space as PKRU is eagerly written in switch_to() and * flush_thread(). */ - memcpy(&fpu->state, &init_fpstate, init_fpstate_copy_size()); + memcpy(&fpu->fpstate->regs, &init_fpstate.regs, init_fpstate_copy_size()); set_thread_flag(TIF_NEED_FPU_LOAD); fpregs_unlock(); } @@ -375,7 +614,7 @@ void fpu__clear_user_states(struct fpu *fpu) fpregs_lock(); if (!cpu_feature_enabled(X86_FEATURE_FPU)) { - fpu_reset_fpstate(); + fpu_reset_fpregs(); fpregs_unlock(); return; } @@ -385,12 +624,11 @@ void fpu__clear_user_states(struct fpu *fpu) * corresponding registers. */ if (xfeatures_mask_supervisor() && - !fpregs_state_valid(fpu, smp_processor_id())) { - os_xrstor(&fpu->state.xsave, xfeatures_mask_supervisor()); - } + !fpregs_state_valid(fpu, smp_processor_id())) + os_xrstor_supervisor(fpu->fpstate); /* Reset user states in registers. */ - restore_fpregs_from_init_fpstate(xfeatures_mask_restore_user()); + restore_fpregs_from_init_fpstate(XFEATURE_MASK_USER_RESTORE); /* * Now all FPU registers have their desired values. Inform the FPU @@ -405,7 +643,8 @@ void fpu__clear_user_states(struct fpu *fpu) void fpu_flush_thread(void) { - fpu_reset_fpstate(); + fpstate_reset(¤t->thread.fpu); + fpu_reset_fpregs(); } /* * Load FPU context before returning to userspace. @@ -445,7 +684,6 @@ void fpregs_mark_activate(void) fpu->last_cpu = smp_processor_id(); clear_thread_flag(TIF_NEED_FPU_LOAD); } -EXPORT_SYMBOL_GPL(fpregs_mark_activate); /* * x87 math exception handling: @@ -468,11 +706,11 @@ int fpu__exception_code(struct fpu *fpu, int trap_nr) * fully reproduce the context of the exception. */ if (boot_cpu_has(X86_FEATURE_FXSR)) { - cwd = fpu->state.fxsave.cwd; - swd = fpu->state.fxsave.swd; + cwd = fpu->fpstate->regs.fxsave.cwd; + swd = fpu->fpstate->regs.fxsave.swd; } else { - cwd = (unsigned short)fpu->state.fsave.cwd; - swd = (unsigned short)fpu->state.fsave.swd; + cwd = (unsigned short)fpu->fpstate->regs.fsave.cwd; + swd = (unsigned short)fpu->fpstate->regs.fsave.swd; } err = swd & ~cwd; @@ -486,7 +724,7 @@ int fpu__exception_code(struct fpu *fpu, int trap_nr) unsigned short mxcsr = MXCSR_DEFAULT; if (boot_cpu_has(X86_FEATURE_XMM)) - mxcsr = fpu->state.fxsave.mxcsr; + mxcsr = fpu->fpstate->regs.fxsave.mxcsr; err = ~(mxcsr >> 7) & mxcsr; } diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c index 64e2992..621f4b6 100644 --- a/arch/x86/kernel/fpu/init.c +++ b/arch/x86/kernel/fpu/init.c @@ -2,7 +2,7 @@ /* * x86 FPU boot time init code: */ -#include +#include #include #include @@ -10,6 +10,10 @@ #include #include +#include "internal.h" +#include "legacy.h" +#include "xstate.h" + /* * Initialize the registers found in all CPUs, CR0 and CR4: */ @@ -34,7 +38,7 @@ static void fpu__init_cpu_generic(void) /* Flush out any pending x87 state: */ #ifdef CONFIG_MATH_EMULATION if (!boot_cpu_has(X86_FEATURE_FPU)) - fpstate_init_soft(¤t->thread.fpu.state.soft); + fpstate_init_soft(¤t->thread.fpu.fpstate->regs.soft); else #endif asm volatile ("fninit"); @@ -121,23 +125,14 @@ static void __init fpu__init_system_mxcsr(void) static void __init fpu__init_system_generic(void) { /* - * Set up the legacy init FPU context. (xstate init might overwrite this - * with a more modern format, if the CPU supports it.) + * Set up the legacy init FPU context. Will be updated when the + * CPU supports XSAVE[S]. */ - fpstate_init(&init_fpstate); + fpstate_init_user(&init_fpstate); fpu__init_system_mxcsr(); } -/* - * Size of the FPU context state. All tasks in the system use the - * same context size, regardless of what portion they use. - * This is inherent to the XSAVE architecture which puts all state - * components into a single, continuous memory block: - */ -unsigned int fpu_kernel_xstate_size __ro_after_init; -EXPORT_SYMBOL_GPL(fpu_kernel_xstate_size); - /* Get alignment of the TYPE. */ #define TYPE_ALIGN(TYPE) offsetof(struct { char x; TYPE test; }, test) @@ -162,13 +157,13 @@ static void __init fpu__init_task_struct_size(void) * Subtract off the static size of the register state. * It potentially has a bunch of padding. */ - task_size -= sizeof(((struct task_struct *)0)->thread.fpu.state); + task_size -= sizeof(current->thread.fpu.__fpstate.regs); /* * Add back the dynamically-calculated register state * size. */ - task_size += fpu_kernel_xstate_size; + task_size += fpu_kernel_cfg.default_size; /* * We dynamically size 'struct fpu', so we require that @@ -177,7 +172,7 @@ static void __init fpu__init_task_struct_size(void) * you hit a compile error here, check the structure to * see if something got added to the end. */ - CHECK_MEMBER_AT_END_OF(struct fpu, state); + CHECK_MEMBER_AT_END_OF(struct fpu, __fpstate); CHECK_MEMBER_AT_END_OF(struct thread_struct, fpu); CHECK_MEMBER_AT_END_OF(struct task_struct, thread); @@ -192,37 +187,34 @@ static void __init fpu__init_task_struct_size(void) */ static void __init fpu__init_system_xstate_size_legacy(void) { - static int on_boot_cpu __initdata = 1; - - WARN_ON_FPU(!on_boot_cpu); - on_boot_cpu = 0; + unsigned int size; /* - * Note that xstate sizes might be overwritten later during - * fpu__init_system_xstate(). + * Note that the size configuration might be overwritten later + * during fpu__init_system_xstate(). */ - - if (!boot_cpu_has(X86_FEATURE_FPU)) { - fpu_kernel_xstate_size = sizeof(struct swregs_state); + if (!cpu_feature_enabled(X86_FEATURE_FPU)) { + size = sizeof(struct swregs_state); + } else if (cpu_feature_enabled(X86_FEATURE_FXSR)) { + size = sizeof(struct fxregs_state); + fpu_user_cfg.legacy_features = XFEATURE_MASK_FPSSE; } else { - if (boot_cpu_has(X86_FEATURE_FXSR)) - fpu_kernel_xstate_size = - sizeof(struct fxregs_state); - else - fpu_kernel_xstate_size = - sizeof(struct fregs_state); + size = sizeof(struct fregs_state); + fpu_user_cfg.legacy_features = XFEATURE_MASK_FP; } - fpu_user_xstate_size = fpu_kernel_xstate_size; + fpu_kernel_cfg.max_size = size; + fpu_kernel_cfg.default_size = size; + fpu_user_cfg.max_size = size; + fpu_user_cfg.default_size = size; + fpstate_reset(¤t->thread.fpu); } -/* Legacy code to initialize eager fpu mode. */ -static void __init fpu__init_system_ctx_switch(void) +static void __init fpu__init_init_fpstate(void) { - static bool on_boot_cpu __initdata = 1; - - WARN_ON_FPU(!on_boot_cpu); - on_boot_cpu = 0; + /* Bring init_fpstate size and features up to date */ + init_fpstate.size = fpu_kernel_cfg.max_size; + init_fpstate.xfeatures = fpu_kernel_cfg.max_features; } /* @@ -231,6 +223,7 @@ static void __init fpu__init_system_ctx_switch(void) */ void __init fpu__init_system(struct cpuinfo_x86 *c) { + fpstate_reset(¤t->thread.fpu); fpu__init_system_early_generic(c); /* @@ -241,8 +234,7 @@ void __init fpu__init_system(struct cpuinfo_x86 *c) fpu__init_system_generic(); fpu__init_system_xstate_size_legacy(); - fpu__init_system_xstate(); + fpu__init_system_xstate(fpu_kernel_cfg.max_size); fpu__init_task_struct_size(); - - fpu__init_system_ctx_switch(); + fpu__init_init_fpstate(); } diff --git a/arch/x86/kernel/fpu/internal.h b/arch/x86/kernel/fpu/internal.h new file mode 100644 index 0000000..dbdb31f --- /dev/null +++ b/arch/x86/kernel/fpu/internal.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __X86_KERNEL_FPU_INTERNAL_H +#define __X86_KERNEL_FPU_INTERNAL_H + +extern struct fpstate init_fpstate; + +/* CPU feature check wrappers */ +static __always_inline __pure bool use_xsave(void) +{ + return cpu_feature_enabled(X86_FEATURE_XSAVE); +} + +static __always_inline __pure bool use_fxsr(void) +{ + return cpu_feature_enabled(X86_FEATURE_FXSR); +} + +#ifdef CONFIG_X86_DEBUG_FPU +# define WARN_ON_FPU(x) WARN_ON_ONCE(x) +#else +# define WARN_ON_FPU(x) ({ (void)(x); 0; }) +#endif + +/* Used in init.c */ +extern void fpstate_init_user(struct fpstate *fpstate); +extern void fpstate_reset(struct fpu *fpu); + +#endif diff --git a/arch/x86/kernel/fpu/legacy.h b/arch/x86/kernel/fpu/legacy.h new file mode 100644 index 0000000..17c26b1 --- /dev/null +++ b/arch/x86/kernel/fpu/legacy.h @@ -0,0 +1,115 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __X86_KERNEL_FPU_LEGACY_H +#define __X86_KERNEL_FPU_LEGACY_H + +#include + +extern unsigned int mxcsr_feature_mask; + +static inline void ldmxcsr(u32 mxcsr) +{ + asm volatile("ldmxcsr %0" :: "m" (mxcsr)); +} + +/* + * Returns 0 on success or the trap number when the operation raises an + * exception. + */ +#define user_insn(insn, output, input...) \ +({ \ + int err; \ + \ + might_fault(); \ + \ + asm volatile(ASM_STAC "\n" \ + "1: " #insn "\n" \ + "2: " ASM_CLAC "\n" \ + _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_FAULT_MCE_SAFE) \ + : [err] "=a" (err), output \ + : "0"(0), input); \ + err; \ +}) + +#define kernel_insn_err(insn, output, input...) \ +({ \ + int err; \ + asm volatile("1:" #insn "\n\t" \ + "2:\n" \ + ".section .fixup,\"ax\"\n" \ + "3: movl $-1,%[err]\n" \ + " jmp 2b\n" \ + ".previous\n" \ + _ASM_EXTABLE(1b, 3b) \ + : [err] "=r" (err), output \ + : "0"(0), input); \ + err; \ +}) + +#define kernel_insn(insn, output, input...) \ + asm volatile("1:" #insn "\n\t" \ + "2:\n" \ + _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_FPU_RESTORE) \ + : output : input) + +static inline int fnsave_to_user_sigframe(struct fregs_state __user *fx) +{ + return user_insn(fnsave %[fx]; fwait, [fx] "=m" (*fx), "m" (*fx)); +} + +static inline int fxsave_to_user_sigframe(struct fxregs_state __user *fx) +{ + if (IS_ENABLED(CONFIG_X86_32)) + return user_insn(fxsave %[fx], [fx] "=m" (*fx), "m" (*fx)); + else + return user_insn(fxsaveq %[fx], [fx] "=m" (*fx), "m" (*fx)); + +} + +static inline void fxrstor(struct fxregs_state *fx) +{ + if (IS_ENABLED(CONFIG_X86_32)) + kernel_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx)); + else + kernel_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx)); +} + +static inline int fxrstor_safe(struct fxregs_state *fx) +{ + if (IS_ENABLED(CONFIG_X86_32)) + return kernel_insn_err(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx)); + else + return kernel_insn_err(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx)); +} + +static inline int fxrstor_from_user_sigframe(struct fxregs_state __user *fx) +{ + if (IS_ENABLED(CONFIG_X86_32)) + return user_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx)); + else + return user_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx)); +} + +static inline void frstor(struct fregs_state *fx) +{ + kernel_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx)); +} + +static inline int frstor_safe(struct fregs_state *fx) +{ + return kernel_insn_err(frstor %[fx], "=m" (*fx), [fx] "m" (*fx)); +} + +static inline int frstor_from_user_sigframe(struct fregs_state __user *fx) +{ + return user_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx)); +} + +static inline void fxsave(struct fxregs_state *fx) +{ + if (IS_ENABLED(CONFIG_X86_32)) + asm volatile( "fxsave %[fx]" : [fx] "=m" (*fx)); + else + asm volatile("fxsaveq %[fx]" : [fx] "=m" (*fx)); +} + +#endif diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c index 66ed317..437d7c9 100644 --- a/arch/x86/kernel/fpu/regset.c +++ b/arch/x86/kernel/fpu/regset.c @@ -5,10 +5,14 @@ #include #include -#include +#include #include #include -#include + +#include "context.h" +#include "internal.h" +#include "legacy.h" +#include "xstate.h" /* * The xstateregs_active() routine is the same as the regset_fpregs_active() routine, @@ -74,8 +78,8 @@ int xfpregs_get(struct task_struct *target, const struct user_regset *regset, sync_fpstate(fpu); if (!use_xsave()) { - return membuf_write(&to, &fpu->state.fxsave, - sizeof(fpu->state.fxsave)); + return membuf_write(&to, &fpu->fpstate->regs.fxsave, + sizeof(fpu->fpstate->regs.fxsave)); } copy_xstate_to_uabi_buf(to, target, XSTATE_COPY_FX); @@ -110,15 +114,15 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset, fpu_force_restore(fpu); /* Copy the state */ - memcpy(&fpu->state.fxsave, &newstate, sizeof(newstate)); + memcpy(&fpu->fpstate->regs.fxsave, &newstate, sizeof(newstate)); /* Clear xmm8..15 */ - BUILD_BUG_ON(sizeof(fpu->state.fxsave.xmm_space) != 16 * 16); - memset(&fpu->state.fxsave.xmm_space[8], 0, 8 * 16); + BUILD_BUG_ON(sizeof(fpu->__fpstate.regs.fxsave.xmm_space) != 16 * 16); + memset(&fpu->fpstate->regs.fxsave.xmm_space[8], 0, 8 * 16); /* Mark FP and SSE as in use when XSAVE is enabled */ if (use_xsave()) - fpu->state.xsave.header.xfeatures |= XFEATURE_MASK_FPSSE; + fpu->fpstate->regs.xsave.header.xfeatures |= XFEATURE_MASK_FPSSE; return 0; } @@ -149,7 +153,7 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset, /* * A whole standard-format XSAVE buffer is needed: */ - if (pos != 0 || count != fpu_user_xstate_size) + if (pos != 0 || count != fpu_user_cfg.max_size) return -EFAULT; if (!kbuf) { @@ -164,7 +168,7 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset, } fpu_force_restore(fpu); - ret = copy_uabi_from_kernel_to_xstate(&fpu->state.xsave, kbuf ?: tmpbuf); + ret = copy_uabi_from_kernel_to_xstate(fpu->fpstate, kbuf ?: tmpbuf); out: vfree(tmpbuf); @@ -283,7 +287,7 @@ static void __convert_from_fxsr(struct user_i387_ia32_struct *env, void convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk) { - __convert_from_fxsr(env, tsk, &tsk->thread.fpu.state.fxsave); + __convert_from_fxsr(env, tsk, &tsk->thread.fpu.fpstate->regs.fxsave); } void convert_to_fxsr(struct fxregs_state *fxsave, @@ -326,7 +330,7 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset, return fpregs_soft_get(target, regset, to); if (!cpu_feature_enabled(X86_FEATURE_FXSR)) { - return membuf_write(&to, &fpu->state.fsave, + return membuf_write(&to, &fpu->fpstate->regs.fsave, sizeof(struct fregs_state)); } @@ -337,7 +341,7 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset, copy_xstate_to_uabi_buf(mb, target, XSTATE_COPY_FP); fx = &fxsave; } else { - fx = &fpu->state.fxsave; + fx = &fpu->fpstate->regs.fxsave; } __convert_from_fxsr(&env, target, fx); @@ -366,16 +370,16 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset, fpu_force_restore(fpu); if (cpu_feature_enabled(X86_FEATURE_FXSR)) - convert_to_fxsr(&fpu->state.fxsave, &env); + convert_to_fxsr(&fpu->fpstate->regs.fxsave, &env); else - memcpy(&fpu->state.fsave, &env, sizeof(env)); + memcpy(&fpu->fpstate->regs.fsave, &env, sizeof(env)); /* * Update the header bit in the xsave header, indicating the * presence of FP. */ if (cpu_feature_enabled(X86_FEATURE_XSAVE)) - fpu->state.xsave.header.xfeatures |= XFEATURE_MASK_FP; + fpu->fpstate->regs.xsave.header.xfeatures |= XFEATURE_MASK_FP; return 0; } diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 831b25c..cc977da 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -7,23 +7,25 @@ #include #include -#include #include #include #include #include +#include #include -static struct _fpx_sw_bytes fx_sw_reserved __ro_after_init; -static struct _fpx_sw_bytes fx_sw_reserved_ia32 __ro_after_init; +#include "context.h" +#include "internal.h" +#include "legacy.h" +#include "xstate.h" /* * Check for the presence of extended state information in the * user fpstate pointer in the sigcontext. */ -static inline int check_xstate_in_sigframe(struct fxregs_state __user *fxbuf, - struct _fpx_sw_bytes *fx_sw) +static inline bool check_xstate_in_sigframe(struct fxregs_state __user *fxbuf, + struct _fpx_sw_bytes *fx_sw) { int min_xstate_size = sizeof(struct fxregs_state) + sizeof(struct xstate_header); @@ -31,12 +33,12 @@ static inline int check_xstate_in_sigframe(struct fxregs_state __user *fxbuf, unsigned int magic2; if (__copy_from_user(fx_sw, &fxbuf->sw_reserved[0], sizeof(*fx_sw))) - return -EFAULT; + return false; /* Check for the first magic field and other error scenarios. */ if (fx_sw->magic1 != FP_XSTATE_MAGIC1 || fx_sw->xstate_size < min_xstate_size || - fx_sw->xstate_size > fpu_user_xstate_size || + fx_sw->xstate_size > current->thread.fpu.fpstate->user_size || fx_sw->xstate_size > fx_sw->extended_size) goto setfx; @@ -47,10 +49,10 @@ static inline int check_xstate_in_sigframe(struct fxregs_state __user *fxbuf, * in the memory layout. */ if (__get_user(magic2, (__u32 __user *)(fpstate + fx_sw->xstate_size))) - return -EFAULT; + return false; if (likely(magic2 == FP_XSTATE_MAGIC2)) - return 0; + return true; setfx: trace_x86_fpu_xstate_check_failed(¤t->thread.fpu); @@ -58,22 +60,22 @@ setfx: fx_sw->magic1 = 0; fx_sw->xstate_size = sizeof(struct fxregs_state); fx_sw->xfeatures = XFEATURE_MASK_FPSSE; - return 0; + return true; } /* * Signal frame handlers. */ -static inline int save_fsave_header(struct task_struct *tsk, void __user *buf) +static inline bool save_fsave_header(struct task_struct *tsk, void __user *buf) { if (use_fxsr()) { - struct xregs_state *xsave = &tsk->thread.fpu.state.xsave; + struct xregs_state *xsave = &tsk->thread.fpu.fpstate->regs.xsave; struct user_i387_ia32_struct env; struct _fpstate_32 __user *fp = buf; fpregs_lock(); if (!test_thread_flag(TIF_NEED_FPU_LOAD)) - fxsave(&tsk->thread.fpu.state.fxsave); + fxsave(&tsk->thread.fpu.fpstate->regs.fxsave); fpregs_unlock(); convert_from_fxsr(&env, tsk); @@ -81,33 +83,54 @@ static inline int save_fsave_header(struct task_struct *tsk, void __user *buf) if (__copy_to_user(buf, &env, sizeof(env)) || __put_user(xsave->i387.swd, &fp->status) || __put_user(X86_FXSR_MAGIC, &fp->magic)) - return -1; + return false; } else { struct fregs_state __user *fp = buf; u32 swd; + if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status)) - return -1; + return false; } - return 0; + return true; +} + +/* + * Prepare the SW reserved portion of the fxsave memory layout, indicating + * the presence of the extended state information in the memory layout + * pointed to by the fpstate pointer in the sigcontext. + * This is saved when ever the FP and extended state context is + * saved on the user stack during the signal handler delivery to the user. + */ +static inline void save_sw_bytes(struct _fpx_sw_bytes *sw_bytes, bool ia32_frame, + struct fpstate *fpstate) +{ + sw_bytes->magic1 = FP_XSTATE_MAGIC1; + sw_bytes->extended_size = fpstate->user_size + FP_XSTATE_MAGIC2_SIZE; + sw_bytes->xfeatures = fpstate->user_xfeatures; + sw_bytes->xstate_size = fpstate->user_size; + + if (ia32_frame) + sw_bytes->extended_size += sizeof(struct fregs_state); } -static inline int save_xstate_epilog(void __user *buf, int ia32_frame) +static inline bool save_xstate_epilog(void __user *buf, int ia32_frame, + struct fpstate *fpstate) { struct xregs_state __user *x = buf; - struct _fpx_sw_bytes *sw_bytes; + struct _fpx_sw_bytes sw_bytes; u32 xfeatures; int err; /* Setup the bytes not touched by the [f]xsave and reserved for SW. */ - sw_bytes = ia32_frame ? &fx_sw_reserved_ia32 : &fx_sw_reserved; - err = __copy_to_user(&x->i387.sw_reserved, sw_bytes, sizeof(*sw_bytes)); + save_sw_bytes(&sw_bytes, ia32_frame, fpstate); + err = __copy_to_user(&x->i387.sw_reserved, &sw_bytes, sizeof(sw_bytes)); if (!use_xsave()) - return err; + return !err; err |= __put_user(FP_XSTATE_MAGIC2, - (__u32 __user *)(buf + fpu_user_xstate_size)); + (__u32 __user *)(buf + fpstate->user_size)); /* * Read the xfeatures which we copied (directly from the cpu or @@ -130,23 +153,17 @@ static inline int save_xstate_epilog(void __user *buf, int ia32_frame) err |= __put_user(xfeatures, (__u32 __user *)&x->header.xfeatures); - return err; + return !err; } static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf) { - int err; - if (use_xsave()) - err = xsave_to_user_sigframe(buf); - else if (use_fxsr()) - err = fxsave_to_user_sigframe((struct fxregs_state __user *) buf); + return xsave_to_user_sigframe(buf); + if (use_fxsr()) + return fxsave_to_user_sigframe((struct fxregs_state __user *) buf); else - err = fnsave_to_user_sigframe((struct fregs_state __user *) buf); - - if (unlikely(err) && __clear_user(buf, fpu_user_xstate_size)) - err = -EFAULT; - return err; + return fnsave_to_user_sigframe((struct fregs_state __user *) buf); } /* @@ -159,10 +176,8 @@ static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf) * buf == buf_fx for 64-bit frames and 32-bit fsave frame. * buf != buf_fx for 32-bit frames with fxstate. * - * Try to save it directly to the user frame with disabled page fault handler. - * If this fails then do the slow path where the FPU state is first saved to - * task's fpu->state and then copy it to the user frame pointed to by the - * aligned pointer 'buf_fx'. + * Save it directly to the user frame with disabled page fault handler. If + * that faults, try to clear the frame which handles the page fault. * * If this is a 32-bit frame with fxstate, put a fsave header before * the aligned state at 'buf_fx'. @@ -170,10 +185,11 @@ static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf) * For [f]xsave state, update the SW reserved fields in the [f]xsave frame * indicating the absence/presence of the extended state to the user. */ -int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) +bool copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) { struct task_struct *tsk = current; - int ia32_fxstate = (buf != buf_fx); + struct fpstate *fpstate = tsk->thread.fpu.fpstate; + bool ia32_fxstate = (buf != buf_fx); int ret; ia32_fxstate &= (IS_ENABLED(CONFIG_X86_32) || @@ -181,13 +197,25 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) if (!static_cpu_has(X86_FEATURE_FPU)) { struct user_i387_ia32_struct fp; + fpregs_soft_get(current, NULL, (struct membuf){.p = &fp, .left = sizeof(fp)}); - return copy_to_user(buf, &fp, sizeof(fp)) ? -EFAULT : 0; + return !copy_to_user(buf, &fp, sizeof(fp)); } if (!access_ok(buf, size)) - return -EACCES; + return false; + + if (use_xsave()) { + struct xregs_state __user *xbuf = buf_fx; + + /* + * Clear the xsave header first, so that reserved fields are + * initialized to zero. + */ + if (__clear_user(&xbuf->header, sizeof(xbuf->header))) + return false; + } retry: /* * Load the FPU registers if they are not valid for the current task. @@ -205,26 +233,26 @@ retry: fpregs_unlock(); if (ret) { - if (!fault_in_pages_writeable(buf_fx, fpu_user_xstate_size)) + if (!__clear_user(buf_fx, fpstate->user_size)) goto retry; - return -EFAULT; + return false; } /* Save the fsave header for the 32-bit frames. */ - if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf)) - return -1; + if ((ia32_fxstate || !use_fxsr()) && !save_fsave_header(tsk, buf)) + return false; - if (use_fxsr() && save_xstate_epilog(buf_fx, ia32_fxstate)) - return -1; + if (use_fxsr() && !save_xstate_epilog(buf_fx, ia32_fxstate, fpstate)) + return false; - return 0; + return true; } -static int __restore_fpregs_from_user(void __user *buf, u64 xrestore, - bool fx_only) +static int __restore_fpregs_from_user(void __user *buf, u64 ufeatures, + u64 xrestore, bool fx_only) { if (use_xsave()) { - u64 init_bv = xfeatures_mask_uabi() & ~xrestore; + u64 init_bv = ufeatures & ~xrestore; int ret; if (likely(!fx_only)) @@ -233,7 +261,7 @@ static int __restore_fpregs_from_user(void __user *buf, u64 xrestore, ret = fxrstor_from_user_sigframe(buf); if (!ret && unlikely(init_bv)) - os_xrstor(&init_fpstate.xsave, init_bv); + os_xrstor(&init_fpstate, init_bv); return ret; } else if (use_fxsr()) { return fxrstor_from_user_sigframe(buf); @@ -246,16 +274,19 @@ static int __restore_fpregs_from_user(void __user *buf, u64 xrestore, * Attempt to restore the FPU registers directly from user memory. * Pagefaults are handled and any errors returned are fatal. */ -static int restore_fpregs_from_user(void __user *buf, u64 xrestore, - bool fx_only, unsigned int size) +static bool restore_fpregs_from_user(void __user *buf, u64 xrestore, + bool fx_only, unsigned int size) { struct fpu *fpu = ¤t->thread.fpu; int ret; retry: fpregs_lock(); + /* Ensure that XFD is up to date */ + xfd_update_state(fpu->fpstate); pagefault_disable(); - ret = __restore_fpregs_from_user(buf, xrestore, fx_only); + ret = __restore_fpregs_from_user(buf, fpu->fpstate->user_xfeatures, + xrestore, fx_only); pagefault_enable(); if (unlikely(ret)) { @@ -275,13 +306,12 @@ retry: fpregs_unlock(); /* Try to handle #PF, but anything else is fatal. */ - if (ret != -EFAULT) - return -EINVAL; + if (ret != X86_TRAP_PF) + return false; - ret = fault_in_pages_readable(buf, size); - if (!ret) + if (!fault_in_pages_readable(buf, size)) goto retry; - return ret; + return false; } /* @@ -294,45 +324,40 @@ retry: * been restored from a user buffer directly. */ if (test_thread_flag(TIF_NEED_FPU_LOAD) && xfeatures_mask_supervisor()) - os_xrstor(&fpu->state.xsave, xfeatures_mask_supervisor()); + os_xrstor_supervisor(fpu->fpstate); fpregs_mark_activate(); fpregs_unlock(); - return 0; + return true; } -static int __fpu_restore_sig(void __user *buf, void __user *buf_fx, - bool ia32_fxstate) +static bool __fpu_restore_sig(void __user *buf, void __user *buf_fx, + bool ia32_fxstate) { - int state_size = fpu_kernel_xstate_size; struct task_struct *tsk = current; struct fpu *fpu = &tsk->thread.fpu; struct user_i387_ia32_struct env; + bool success, fx_only = false; + union fpregs_state *fpregs; + unsigned int state_size; u64 user_xfeatures = 0; - bool fx_only = false; - int ret; if (use_xsave()) { struct _fpx_sw_bytes fx_sw_user; - ret = check_xstate_in_sigframe(buf_fx, &fx_sw_user); - if (unlikely(ret)) - return ret; + if (!check_xstate_in_sigframe(buf_fx, &fx_sw_user)) + return false; fx_only = !fx_sw_user.magic1; state_size = fx_sw_user.xstate_size; user_xfeatures = fx_sw_user.xfeatures; } else { user_xfeatures = XFEATURE_MASK_FPSSE; + state_size = fpu->fpstate->user_size; } if (likely(!ia32_fxstate)) { - /* - * Attempt to restore the FPU registers directly from user - * memory. For that to succeed, the user access cannot cause page - * faults. If it does, fall back to the slow path below, going - * through the kernel buffer with the enabled pagefault handler. - */ + /* Restore the FPU registers directly from user memory. */ return restore_fpregs_from_user(buf_fx, user_xfeatures, fx_only, state_size); } @@ -342,9 +367,8 @@ static int __fpu_restore_sig(void __user *buf, void __user *buf_fx, * to be ignored for histerical raisins. The legacy state is folded * in once the larger state has been copied. */ - ret = __copy_from_user(&env, buf, sizeof(env)); - if (ret) - return ret; + if (__copy_from_user(&env, buf, sizeof(env))) + return false; /* * By setting TIF_NEED_FPU_LOAD it is ensured that our xstate is @@ -363,38 +387,38 @@ static int __fpu_restore_sig(void __user *buf, void __user *buf_fx, * the right place in memory. It's ia32 mode. Shrug. */ if (xfeatures_mask_supervisor()) - os_xsave(&fpu->state.xsave); + os_xsave(fpu->fpstate); set_thread_flag(TIF_NEED_FPU_LOAD); } __fpu_invalidate_fpregs_state(fpu); __cpu_invalidate_fpregs_state(); fpregs_unlock(); + fpregs = &fpu->fpstate->regs; if (use_xsave() && !fx_only) { - ret = copy_sigframe_from_user_to_xstate(&fpu->state.xsave, buf_fx); - if (ret) - return ret; + if (copy_sigframe_from_user_to_xstate(fpu->fpstate, buf_fx)) + return false; } else { - if (__copy_from_user(&fpu->state.fxsave, buf_fx, - sizeof(fpu->state.fxsave))) - return -EFAULT; + if (__copy_from_user(&fpregs->fxsave, buf_fx, + sizeof(fpregs->fxsave))) + return false; if (IS_ENABLED(CONFIG_X86_64)) { /* Reject invalid MXCSR values. */ - if (fpu->state.fxsave.mxcsr & ~mxcsr_feature_mask) - return -EINVAL; + if (fpregs->fxsave.mxcsr & ~mxcsr_feature_mask) + return false; } else { /* Mask invalid bits out for historical reasons (broken hardware). */ - fpu->state.fxsave.mxcsr &= mxcsr_feature_mask; + fpregs->fxsave.mxcsr &= mxcsr_feature_mask; } /* Enforce XFEATURE_MASK_FPSSE when XSAVE is enabled */ if (use_xsave()) - fpu->state.xsave.header.xfeatures |= XFEATURE_MASK_FPSSE; + fpregs->xsave.header.xfeatures |= XFEATURE_MASK_FPSSE; } /* Fold the legacy FP storage */ - convert_to_fxsr(&fpu->state.fxsave, &env); + convert_to_fxsr(&fpregs->fxsave, &env); fpregs_lock(); if (use_xsave()) { @@ -409,40 +433,45 @@ static int __fpu_restore_sig(void __user *buf, void __user *buf_fx, */ u64 mask = user_xfeatures | xfeatures_mask_supervisor(); - fpu->state.xsave.header.xfeatures &= mask; - ret = os_xrstor_safe(&fpu->state.xsave, xfeatures_mask_all); + fpregs->xsave.header.xfeatures &= mask; + success = !os_xrstor_safe(fpu->fpstate, + fpu_kernel_cfg.max_features); } else { - ret = fxrstor_safe(&fpu->state.fxsave); + success = !fxrstor_safe(&fpregs->fxsave); } - if (likely(!ret)) + if (likely(success)) fpregs_mark_activate(); fpregs_unlock(); - return ret; + return success; } -static inline int xstate_sigframe_size(void) + +static inline unsigned int xstate_sigframe_size(struct fpstate *fpstate) { - return use_xsave() ? fpu_user_xstate_size + FP_XSTATE_MAGIC2_SIZE : - fpu_user_xstate_size; + unsigned int size = fpstate->user_size; + + return use_xsave() ? size + FP_XSTATE_MAGIC2_SIZE : size; } /* * Restore FPU state from a sigframe: */ -int fpu__restore_sig(void __user *buf, int ia32_frame) +bool fpu__restore_sig(void __user *buf, int ia32_frame) { - unsigned int size = xstate_sigframe_size(); struct fpu *fpu = ¤t->thread.fpu; void __user *buf_fx = buf; bool ia32_fxstate = false; - int ret; + bool success = false; + unsigned int size; if (unlikely(!buf)) { fpu__clear_user_states(fpu); - return 0; + return true; } + size = xstate_sigframe_size(fpu->fpstate); + ia32_frame &= (IS_ENABLED(CONFIG_X86_32) || IS_ENABLED(CONFIG_IA32_EMULATION)); @@ -456,30 +485,28 @@ int fpu__restore_sig(void __user *buf, int ia32_frame) ia32_fxstate = true; } - if (!access_ok(buf, size)) { - ret = -EACCES; + if (!access_ok(buf, size)) goto out; - } if (!IS_ENABLED(CONFIG_X86_64) && !cpu_feature_enabled(X86_FEATURE_FPU)) { - ret = fpregs_soft_set(current, NULL, 0, - sizeof(struct user_i387_ia32_struct), - NULL, buf); + success = !fpregs_soft_set(current, NULL, 0, + sizeof(struct user_i387_ia32_struct), + NULL, buf); } else { - ret = __fpu_restore_sig(buf, buf_fx, ia32_fxstate); + success = __fpu_restore_sig(buf, buf_fx, ia32_fxstate); } out: - if (unlikely(ret)) + if (unlikely(!success)) fpu__clear_user_states(fpu); - return ret; + return success; } unsigned long fpu__alloc_mathframe(unsigned long sp, int ia32_frame, unsigned long *buf_fx, unsigned long *size) { - unsigned long frame_size = xstate_sigframe_size(); + unsigned long frame_size = xstate_sigframe_size(current->thread.fpu.fpstate); *buf_fx = sp = round_down(sp - frame_size, 64); if (ia32_frame && use_fxsr()) { @@ -492,9 +519,12 @@ fpu__alloc_mathframe(unsigned long sp, int ia32_frame, return sp; } -unsigned long fpu__get_fpstate_size(void) +unsigned long __init fpu__get_fpstate_size(void) { - unsigned long ret = xstate_sigframe_size(); + unsigned long ret = fpu_user_cfg.max_size; + + if (use_xsave()) + ret += FP_XSTATE_MAGIC2_SIZE; /* * This space is needed on (most) 32-bit kernels, or when a 32-bit @@ -510,28 +540,3 @@ unsigned long fpu__get_fpstate_size(void) return ret; } -/* - * Prepare the SW reserved portion of the fxsave memory layout, indicating - * the presence of the extended state information in the memory layout - * pointed by the fpstate pointer in the sigcontext. - * This will be saved when ever the FP and extended state context is - * saved on the user stack during the signal handler delivery to the user. - */ -void fpu__init_prepare_fx_sw_frame(void) -{ - int size = fpu_user_xstate_size + FP_XSTATE_MAGIC2_SIZE; - - fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1; - fx_sw_reserved.extended_size = size; - fx_sw_reserved.xfeatures = xfeatures_mask_uabi(); - fx_sw_reserved.xstate_size = fpu_user_xstate_size; - - if (IS_ENABLED(CONFIG_IA32_EMULATION) || - IS_ENABLED(CONFIG_X86_32)) { - int fsave_header_size = sizeof(struct fregs_state); - - fx_sw_reserved_ia32 = fx_sw_reserved; - fx_sw_reserved_ia32.extended_size = size + fsave_header_size; - } -} - diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index c8def1b..d288294 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -4,21 +4,33 @@ * * Author: Suresh Siddha */ +#include #include #include #include +#include #include #include #include +#include #include -#include -#include #include -#include +#include +#include #include -#include +#include +#include + +#include "context.h" +#include "internal.h" +#include "legacy.h" +#include "xstate.h" + +#define for_each_extended_xfeature(bit, mask) \ + (bit) = FIRST_EXTENDED_XFEATURE; \ + for_each_set_bit_from(bit, (unsigned long *)&(mask), 8 * sizeof(mask)) /* * Although we spell it out in here, the Processor Trace @@ -39,29 +51,32 @@ static const char *xfeature_names[] = "Protection Keys User registers", "PASID state", "unknown xstate feature" , + "unknown xstate feature" , + "unknown xstate feature" , + "unknown xstate feature" , + "unknown xstate feature" , + "unknown xstate feature" , + "AMX Tile config" , + "AMX Tile data" , + "unknown xstate feature" , }; -static short xsave_cpuid_features[] __initdata = { - X86_FEATURE_FPU, - X86_FEATURE_XMM, - X86_FEATURE_AVX, - X86_FEATURE_MPX, - X86_FEATURE_MPX, - X86_FEATURE_AVX512F, - X86_FEATURE_AVX512F, - X86_FEATURE_AVX512F, - X86_FEATURE_INTEL_PT, - X86_FEATURE_PKU, - X86_FEATURE_ENQCMD, +static unsigned short xsave_cpuid_features[] __initdata = { + [XFEATURE_FP] = X86_FEATURE_FPU, + [XFEATURE_SSE] = X86_FEATURE_XMM, + [XFEATURE_YMM] = X86_FEATURE_AVX, + [XFEATURE_BNDREGS] = X86_FEATURE_MPX, + [XFEATURE_BNDCSR] = X86_FEATURE_MPX, + [XFEATURE_OPMASK] = X86_FEATURE_AVX512F, + [XFEATURE_ZMM_Hi256] = X86_FEATURE_AVX512F, + [XFEATURE_Hi16_ZMM] = X86_FEATURE_AVX512F, + [XFEATURE_PT_UNIMPLEMENTED_SO_FAR] = X86_FEATURE_INTEL_PT, + [XFEATURE_PKRU] = X86_FEATURE_PKU, + [XFEATURE_PASID] = X86_FEATURE_ENQCMD, + [XFEATURE_XTILE_CFG] = X86_FEATURE_AMX_TILE, + [XFEATURE_XTILE_DATA] = X86_FEATURE_AMX_TILE, }; -/* - * This represents the full set of bits that should ever be set in a kernel - * XSAVE buffer, both supervisor and user xstates. - */ -u64 xfeatures_mask_all __ro_after_init; -EXPORT_SYMBOL_GPL(xfeatures_mask_all); - static unsigned int xstate_offsets[XFEATURE_MAX] __ro_after_init = { [ 0 ... XFEATURE_MAX - 1] = -1}; static unsigned int xstate_sizes[XFEATURE_MAX] __ro_after_init = @@ -72,20 +87,13 @@ static unsigned int xstate_supervisor_only_offsets[XFEATURE_MAX] __ro_after_init { [ 0 ... XFEATURE_MAX - 1] = -1}; /* - * The XSAVE area of kernel can be in standard or compacted format; - * it is always in standard format for user mode. This is the user - * mode standard format size used for signal and ptrace frames. - */ -unsigned int fpu_user_xstate_size __ro_after_init; - -/* * Return whether the system supports a given xfeature. * * Also return the name of the (most advanced) feature that the caller requested: */ int cpu_has_xfeatures(u64 xfeatures_needed, const char **feature_name) { - u64 xfeatures_missing = xfeatures_needed & ~xfeatures_mask_all; + u64 xfeatures_missing = xfeatures_needed & ~fpu_kernel_cfg.max_features; if (unlikely(feature_name)) { long xfeature_idx, max_idx; @@ -135,17 +143,26 @@ static bool xfeature_is_supervisor(int xfeature_nr) */ void fpu__init_cpu_xstate(void) { - if (!boot_cpu_has(X86_FEATURE_XSAVE) || !xfeatures_mask_all) + if (!boot_cpu_has(X86_FEATURE_XSAVE) || !fpu_kernel_cfg.max_features) return; cr4_set_bits(X86_CR4_OSXSAVE); /* + * Must happen after CR4 setup and before xsetbv() to allow KVM + * lazy passthrough. Write independent of the dynamic state static + * key as that does not work on the boot CPU. This also ensures + * that any stale state is wiped out from XFD. + */ + if (cpu_feature_enabled(X86_FEATURE_XFD)) + wrmsrl(MSR_IA32_XFD, init_fpstate.xfd); + + /* * XCR_XFEATURE_ENABLED_MASK (aka. XCR0) sets user features * managed by XSAVE{C, OPT, S} and XRSTOR{S}. Only XSAVE user * states can be set here. */ - xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask_uabi()); + xsetbv(XCR_XFEATURE_ENABLED_MASK, fpu_user_cfg.max_features); /* * MSR_IA32_XSS sets supervisor states managed by XSAVES. @@ -158,7 +175,7 @@ void fpu__init_cpu_xstate(void) static bool xfeature_enabled(enum xfeature xfeature) { - return xfeatures_mask_all & BIT_ULL(xfeature); + return fpu_kernel_cfg.max_features & BIT_ULL(xfeature); } /* @@ -184,10 +201,7 @@ static void __init setup_xstate_features(void) xstate_sizes[XFEATURE_SSE] = sizeof_field(struct fxregs_state, xmm_space); - for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { - if (!xfeature_enabled(i)) - continue; - + for_each_extended_xfeature(i, fpu_kernel_cfg.max_features) { cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx); xstate_sizes[i] = eax; @@ -236,6 +250,8 @@ static void __init print_xstate_features(void) print_xstate_feature(XFEATURE_MASK_Hi16_ZMM); print_xstate_feature(XFEATURE_MASK_PKRU); print_xstate_feature(XFEATURE_MASK_PASID); + print_xstate_feature(XFEATURE_MASK_XTILE_CFG); + print_xstate_feature(XFEATURE_MASK_XTILE_DATA); } /* @@ -291,20 +307,15 @@ static void __init setup_xstate_comp_offsets(void) xstate_comp_offsets[XFEATURE_SSE] = offsetof(struct fxregs_state, xmm_space); - if (!boot_cpu_has(X86_FEATURE_XSAVES)) { - for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { - if (xfeature_enabled(i)) - xstate_comp_offsets[i] = xstate_offsets[i]; - } + if (!cpu_feature_enabled(X86_FEATURE_XSAVES)) { + for_each_extended_xfeature(i, fpu_kernel_cfg.max_features) + xstate_comp_offsets[i] = xstate_offsets[i]; return; } next_offset = FXSAVE_SIZE + XSAVE_HDR_SIZE; - for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { - if (!xfeature_enabled(i)) - continue; - + for_each_extended_xfeature(i, fpu_kernel_cfg.max_features) { if (xfeature_is_aligned(i)) next_offset = ALIGN(next_offset, 64); @@ -328,8 +339,8 @@ static void __init setup_supervisor_only_offsets(void) next_offset = FXSAVE_SIZE + XSAVE_HDR_SIZE; - for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { - if (!xfeature_enabled(i) || !xfeature_is_supervisor(i)) + for_each_extended_xfeature(i, fpu_kernel_cfg.max_features) { + if (!xfeature_is_supervisor(i)) continue; if (xfeature_is_aligned(i)) @@ -347,15 +358,36 @@ static void __init print_xstate_offset_size(void) { int i; - for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { - if (!xfeature_enabled(i)) - continue; + for_each_extended_xfeature(i, fpu_kernel_cfg.max_features) { pr_info("x86/fpu: xstate_offset[%d]: %4d, xstate_sizes[%d]: %4d\n", i, xstate_comp_offsets[i], i, xstate_sizes[i]); } } /* + * This function is called only during boot time when x86 caps are not set + * up and alternative can not be used yet. + */ +static __init void os_xrstor_booting(struct xregs_state *xstate) +{ + u64 mask = fpu_kernel_cfg.max_features & XFEATURE_MASK_FPSTATE; + u32 lmask = mask; + u32 hmask = mask >> 32; + int err; + + if (cpu_feature_enabled(X86_FEATURE_XSAVES)) + XSTATE_OP(XRSTORS, xstate, lmask, hmask, err); + else + XSTATE_OP(XRSTOR, xstate, lmask, hmask, err); + + /* + * We should never fault when copying from a kernel buffer, and the FPU + * state we set at boot time should be valid. + */ + WARN_ON_FPU(err); +} + +/* * All supported features have either init state all zeros or are * handled in setup_init_fpu() individually. This is an explicit * feature list and does not use XFEATURE_MASK*SUPPORTED to catch @@ -372,36 +404,30 @@ static void __init print_xstate_offset_size(void) XFEATURE_MASK_PKRU | \ XFEATURE_MASK_BNDREGS | \ XFEATURE_MASK_BNDCSR | \ - XFEATURE_MASK_PASID) + XFEATURE_MASK_PASID | \ + XFEATURE_MASK_XTILE) /* * setup the xstate image representing the init state */ static void __init setup_init_fpu_buf(void) { - static int on_boot_cpu __initdata = 1; - BUILD_BUG_ON((XFEATURE_MASK_USER_SUPPORTED | XFEATURE_MASK_SUPERVISOR_SUPPORTED) != XFEATURES_INIT_FPSTATE_HANDLED); - WARN_ON_FPU(!on_boot_cpu); - on_boot_cpu = 0; - if (!boot_cpu_has(X86_FEATURE_XSAVE)) return; setup_xstate_features(); print_xstate_features(); - if (boot_cpu_has(X86_FEATURE_XSAVES)) - init_fpstate.xsave.header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT | - xfeatures_mask_all; + xstate_init_xcomp_bv(&init_fpstate.regs.xsave, fpu_kernel_cfg.max_features); /* * Init all the features state with header.xfeatures being 0x0 */ - os_xrstor_booting(&init_fpstate.xsave); + os_xrstor_booting(&init_fpstate.regs.xsave); /* * All components are now in init state. Read the state back so @@ -419,7 +445,7 @@ static void __init setup_init_fpu_buf(void) * state is all zeroes or if not to add the necessary handling * here. */ - fxsave(&init_fpstate.fxsave); + fxsave(&init_fpstate.regs.fxsave); } static int xfeature_uncompacted_offset(int xfeature_nr) @@ -451,10 +477,11 @@ int xfeature_size(int xfeature_nr) } /* Validate an xstate header supplied by userspace (ptrace or sigreturn) */ -static int validate_user_xstate_header(const struct xstate_header *hdr) +static int validate_user_xstate_header(const struct xstate_header *hdr, + struct fpstate *fpstate) { /* No unknown or supervisor features may be set */ - if (hdr->xfeatures & ~xfeatures_mask_uabi()) + if (hdr->xfeatures & ~fpstate->user_xfeatures) return -EINVAL; /* Userspace must use the uncompacted format */ @@ -474,7 +501,7 @@ static int validate_user_xstate_header(const struct xstate_header *hdr) return 0; } -static void __xstate_dump_leaves(void) +static void __init __xstate_dump_leaves(void) { int i; u32 eax, ebx, ecx, edx; @@ -509,12 +536,73 @@ static void __xstate_dump_leaves(void) } \ } while (0) +/** + * check_xtile_data_against_struct - Check tile data state size. + * + * Calculate the state size by multiplying the single tile size which is + * recorded in a C struct, and the number of tiles that the CPU informs. + * Compare the provided size with the calculation. + * + * @size: The tile data state size + * + * Returns: 0 on success, -EINVAL on mismatch. + */ +static int __init check_xtile_data_against_struct(int size) +{ + u32 max_palid, palid, state_size; + u32 eax, ebx, ecx, edx; + u16 max_tile; + + /* + * Check the maximum palette id: + * eax: the highest numbered palette subleaf. + */ + cpuid_count(TILE_CPUID, 0, &max_palid, &ebx, &ecx, &edx); + + /* + * Cross-check each tile size and find the maximum number of + * supported tiles. + */ + for (palid = 1, max_tile = 0; palid <= max_palid; palid++) { + u16 tile_size, max; + + /* + * Check the tile size info: + * eax[31:16]: bytes per title + * ebx[31:16]: the max names (or max number of tiles) + */ + cpuid_count(TILE_CPUID, palid, &eax, &ebx, &edx, &edx); + tile_size = eax >> 16; + max = ebx >> 16; + + if (tile_size != sizeof(struct xtile_data)) { + pr_err("%s: struct is %zu bytes, cpu xtile %d bytes\n", + __stringify(XFEATURE_XTILE_DATA), + sizeof(struct xtile_data), tile_size); + __xstate_dump_leaves(); + return -EINVAL; + } + + if (max > max_tile) + max_tile = max; + } + + state_size = sizeof(struct xtile_data) * max_tile; + if (size != state_size) { + pr_err("%s: calculated size is %u bytes, cpu state %d bytes\n", + __stringify(XFEATURE_XTILE_DATA), state_size, size); + __xstate_dump_leaves(); + return -EINVAL; + } + return 0; +} + /* * We have a C struct for each 'xstate'. We need to ensure * that our software representation matches what the CPU * tells us about the state's size. */ -static void check_xstate_against_struct(int nr) +static bool __init check_xstate_against_struct(int nr) { /* * Ask the CPU for the size of the state. @@ -532,6 +620,11 @@ static void check_xstate_against_struct(int nr) XCHECK_SZ(sz, nr, XFEATURE_Hi16_ZMM, struct avx_512_hi16_state); XCHECK_SZ(sz, nr, XFEATURE_PKRU, struct pkru_state); XCHECK_SZ(sz, nr, XFEATURE_PASID, struct ia32_pasid_state); + XCHECK_SZ(sz, nr, XFEATURE_XTILE_CFG, struct xtile_cfg); + + /* The tile data size varies between implementations. */ + if (nr == XFEATURE_XTILE_DATA) + check_xtile_data_against_struct(sz); /* * Make *SURE* to add any feature numbers in below if @@ -541,10 +634,39 @@ static void check_xstate_against_struct(int nr) if ((nr < XFEATURE_YMM) || (nr >= XFEATURE_MAX) || (nr == XFEATURE_PT_UNIMPLEMENTED_SO_FAR) || - ((nr >= XFEATURE_RSRVD_COMP_11) && (nr <= XFEATURE_LBR))) { + ((nr >= XFEATURE_RSRVD_COMP_11) && (nr <= XFEATURE_RSRVD_COMP_16))) { WARN_ONCE(1, "no structure for xstate: %d\n", nr); XSTATE_WARN_ON(1); + return false; + } + return true; +} + +static unsigned int xstate_calculate_size(u64 xfeatures, bool compacted) +{ + unsigned int size = FXSAVE_SIZE + XSAVE_HDR_SIZE; + int i; + + for_each_extended_xfeature(i, xfeatures) { + /* Align from the end of the previous feature */ + if (xfeature_is_aligned(i)) + size = ALIGN(size, 64); + /* + * In compacted format the enabled features are packed, + * i.e. disabled features do not occupy space. + * + * In non-compacted format the offsets are fixed and + * disabled states still occupy space in the memory buffer. + */ + if (!compacted) + size = xfeature_uncompacted_offset(i); + /* + * Add the feature size even for non-compacted format + * to make the end result correct + */ + size += xfeature_size(i); } + return size; } /* @@ -556,44 +678,29 @@ static void check_xstate_against_struct(int nr) * covered by these checks. Only the size of the buffer for task->fpu * is checked here. */ -static void do_extra_xstate_size_checks(void) +static bool __init paranoid_xstate_size_valid(unsigned int kernel_size) { - int paranoid_xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE; + bool compacted = cpu_feature_enabled(X86_FEATURE_XSAVES); + unsigned int size = FXSAVE_SIZE + XSAVE_HDR_SIZE; int i; - for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { - if (!xfeature_enabled(i)) - continue; - - check_xstate_against_struct(i); + for_each_extended_xfeature(i, fpu_kernel_cfg.max_features) { + if (!check_xstate_against_struct(i)) + return false; /* * Supervisor state components can be managed only by * XSAVES. */ - if (!cpu_feature_enabled(X86_FEATURE_XSAVES)) - XSTATE_WARN_ON(xfeature_is_supervisor(i)); - - /* Align from the end of the previous feature */ - if (xfeature_is_aligned(i)) - paranoid_xstate_size = ALIGN(paranoid_xstate_size, 64); - /* - * The offset of a given state in the non-compacted - * format is given to us in a CPUID leaf. We check - * them for being ordered (increasing offsets) in - * setup_xstate_features(). XSAVES uses compacted format. - */ - if (!cpu_feature_enabled(X86_FEATURE_XSAVES)) - paranoid_xstate_size = xfeature_uncompacted_offset(i); - /* - * The compacted-format offset always depends on where - * the previous state ended. - */ - paranoid_xstate_size += xfeature_size(i); + if (!compacted && xfeature_is_supervisor(i)) { + XSTATE_WARN_ON(1); + return false; + } } - XSTATE_WARN_ON(paranoid_xstate_size != fpu_kernel_xstate_size); + size = xstate_calculate_size(fpu_kernel_cfg.max_features, compacted); + XSTATE_WARN_ON(size != kernel_size); + return size == kernel_size; } - /* * Get total size of enabled xstates in XCR0 | IA32_XSS. * @@ -644,7 +751,7 @@ static unsigned int __init get_xsaves_size_no_independent(void) return size; } -static unsigned int __init get_xsave_size(void) +static unsigned int __init get_xsave_size_user(void) { unsigned int eax, ebx, ecx, edx; /* @@ -662,44 +769,54 @@ static unsigned int __init get_xsave_size(void) * Will the runtime-enumerated 'xstate_size' fit in the init * task's statically-allocated buffer? */ -static bool is_supported_xstate_size(unsigned int test_xstate_size) +static bool __init is_supported_xstate_size(unsigned int test_xstate_size) { - if (test_xstate_size <= sizeof(union fpregs_state)) + if (test_xstate_size <= sizeof(init_fpstate.regs)) return true; pr_warn("x86/fpu: xstate buffer too small (%zu < %d), disabling xsave\n", - sizeof(union fpregs_state), test_xstate_size); + sizeof(init_fpstate.regs), test_xstate_size); return false; } static int __init init_xstate_size(void) { /* Recompute the context size for enabled features: */ - unsigned int possible_xstate_size; - unsigned int xsave_size; + unsigned int user_size, kernel_size, kernel_default_size; + bool compacted = cpu_feature_enabled(X86_FEATURE_XSAVES); - xsave_size = get_xsave_size(); + /* Uncompacted user space size */ + user_size = get_xsave_size_user(); - if (boot_cpu_has(X86_FEATURE_XSAVES)) - possible_xstate_size = get_xsaves_size_no_independent(); + /* + * XSAVES kernel size includes supervisor states and + * uses compacted format when available. + * + * XSAVE does not support supervisor states so + * kernel and user size is identical. + */ + if (compacted) + kernel_size = get_xsaves_size_no_independent(); else - possible_xstate_size = xsave_size; + kernel_size = user_size; + + kernel_default_size = + xstate_calculate_size(fpu_kernel_cfg.default_features, compacted); - /* Ensure we have the space to store all enabled: */ - if (!is_supported_xstate_size(possible_xstate_size)) + /* Ensure we have the space to store all default enabled features. */ + if (!is_supported_xstate_size(kernel_default_size)) return -EINVAL; - /* - * The size is OK, we are definitely going to use xsave, - * make it known to the world that we need more space. - */ - fpu_kernel_xstate_size = possible_xstate_size; - do_extra_xstate_size_checks(); + if (!paranoid_xstate_size_valid(kernel_size)) + return -EINVAL; + + fpu_kernel_cfg.max_size = kernel_size; + fpu_user_cfg.max_size = user_size; + + fpu_kernel_cfg.default_size = kernel_default_size; + fpu_user_cfg.default_size = + xstate_calculate_size(fpu_user_cfg.default_features, false); - /* - * User space is always in standard format. - */ - fpu_user_xstate_size = xsave_size; return 0; } @@ -707,28 +824,38 @@ static int __init init_xstate_size(void) * We enabled the XSAVE hardware, but something went wrong and * we can not use it. Disable it. */ -static void fpu__init_disable_system_xstate(void) +static void __init fpu__init_disable_system_xstate(unsigned int legacy_size) { - xfeatures_mask_all = 0; + fpu_kernel_cfg.max_features = 0; cr4_clear_bits(X86_CR4_OSXSAVE); setup_clear_cpu_cap(X86_FEATURE_XSAVE); + + /* Restore the legacy size.*/ + fpu_kernel_cfg.max_size = legacy_size; + fpu_kernel_cfg.default_size = legacy_size; + fpu_user_cfg.max_size = legacy_size; + fpu_user_cfg.default_size = legacy_size; + + /* + * Prevent enabling the static branch which enables writes to the + * XFD MSR. + */ + init_fpstate.xfd = 0; + + fpstate_reset(¤t->thread.fpu); } /* * Enable and initialize the xsave feature. * Called once per system bootup. */ -void __init fpu__init_system_xstate(void) +void __init fpu__init_system_xstate(unsigned int legacy_size) { unsigned int eax, ebx, ecx, edx; - static int on_boot_cpu __initdata = 1; u64 xfeatures; int err; int i; - WARN_ON_FPU(!on_boot_cpu); - on_boot_cpu = 0; - if (!boot_cpu_has(X86_FEATURE_FPU)) { pr_info("x86/fpu: No FPU detected\n"); return; @@ -749,22 +876,22 @@ void __init fpu__init_system_xstate(void) * Find user xstates supported by the processor. */ cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx); - xfeatures_mask_all = eax + ((u64)edx << 32); + fpu_kernel_cfg.max_features = eax + ((u64)edx << 32); /* * Find supervisor xstates supported by the processor. */ cpuid_count(XSTATE_CPUID, 1, &eax, &ebx, &ecx, &edx); - xfeatures_mask_all |= ecx + ((u64)edx << 32); + fpu_kernel_cfg.max_features |= ecx + ((u64)edx << 32); - if ((xfeatures_mask_uabi() & XFEATURE_MASK_FPSSE) != XFEATURE_MASK_FPSSE) { + if ((fpu_kernel_cfg.max_features & XFEATURE_MASK_FPSSE) != XFEATURE_MASK_FPSSE) { /* * This indicates that something really unexpected happened * with the enumeration. Disable XSAVE and try to continue * booting without it. This is too early to BUG(). */ pr_err("x86/fpu: FP/SSE not present amongst the CPU's xstate features: 0x%llx.\n", - xfeatures_mask_all); + fpu_kernel_cfg.max_features); goto out_disable; } @@ -772,15 +899,39 @@ void __init fpu__init_system_xstate(void) * Clear XSAVE features that are disabled in the normal CPUID. */ for (i = 0; i < ARRAY_SIZE(xsave_cpuid_features); i++) { - if (!boot_cpu_has(xsave_cpuid_features[i])) - xfeatures_mask_all &= ~BIT_ULL(i); + unsigned short cid = xsave_cpuid_features[i]; + + /* Careful: X86_FEATURE_FPU is 0! */ + if ((i != XFEATURE_FP && !cid) || !boot_cpu_has(cid)) + fpu_kernel_cfg.max_features &= ~BIT_ULL(i); } - xfeatures_mask_all &= XFEATURE_MASK_USER_SUPPORTED | + if (!cpu_feature_enabled(X86_FEATURE_XFD)) + fpu_kernel_cfg.max_features &= ~XFEATURE_MASK_USER_DYNAMIC; + + fpu_kernel_cfg.max_features &= XFEATURE_MASK_USER_SUPPORTED | XFEATURE_MASK_SUPERVISOR_SUPPORTED; + fpu_user_cfg.max_features = fpu_kernel_cfg.max_features; + fpu_user_cfg.max_features &= XFEATURE_MASK_USER_SUPPORTED; + + /* Clean out dynamic features from default */ + fpu_kernel_cfg.default_features = fpu_kernel_cfg.max_features; + fpu_kernel_cfg.default_features &= ~XFEATURE_MASK_USER_DYNAMIC; + + fpu_user_cfg.default_features = fpu_user_cfg.max_features; + fpu_user_cfg.default_features &= ~XFEATURE_MASK_USER_DYNAMIC; + /* Store it for paranoia check at the end */ - xfeatures = xfeatures_mask_all; + xfeatures = fpu_kernel_cfg.max_features; + + /* + * Initialize the default XFD state in initfp_state and enable the + * dynamic sizing mechanism if dynamic states are available. The + * static key cannot be enabled here because this runs before + * jump_label_init(). This is delayed to an initcall. + */ + init_fpstate.xfd = fpu_user_cfg.max_features & XFEATURE_MASK_USER_DYNAMIC; /* Enable xstate instructions to be able to continue with initialization: */ fpu__init_cpu_xstate(); @@ -788,13 +939,16 @@ void __init fpu__init_system_xstate(void) if (err) goto out_disable; + /* Reset the state for the current task */ + fpstate_reset(¤t->thread.fpu); + /* * Update info used for ptrace frames; use standard-format size and no * supervisor xstates: */ - update_regset_xstate_info(fpu_user_xstate_size, xfeatures_mask_uabi()); + update_regset_xstate_info(fpu_user_cfg.max_size, + fpu_user_cfg.max_features); - fpu__init_prepare_fx_sw_frame(); setup_init_fpu_buf(); setup_xstate_comp_offsets(); setup_supervisor_only_offsets(); @@ -803,22 +957,22 @@ void __init fpu__init_system_xstate(void) * Paranoia check whether something in the setup modified the * xfeatures mask. */ - if (xfeatures != xfeatures_mask_all) { + if (xfeatures != fpu_kernel_cfg.max_features) { pr_err("x86/fpu: xfeatures modified from 0x%016llx to 0x%016llx during init, disabling XSAVE\n", - xfeatures, xfeatures_mask_all); + xfeatures, fpu_kernel_cfg.max_features); goto out_disable; } print_xstate_offset_size(); pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is %d bytes, using '%s' format.\n", - xfeatures_mask_all, - fpu_kernel_xstate_size, + fpu_kernel_cfg.max_features, + fpu_kernel_cfg.max_size, boot_cpu_has(X86_FEATURE_XSAVES) ? "compacted" : "standard"); return; out_disable: /* something went wrong, try to boot without any XSAVE support */ - fpu__init_disable_system_xstate(); + fpu__init_disable_system_xstate(legacy_size); } /* @@ -830,7 +984,7 @@ void fpu__resume_cpu(void) * Restore XCR0 on xsave capable CPUs: */ if (cpu_feature_enabled(X86_FEATURE_XSAVE)) - xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask_uabi()); + xsetbv(XCR_XFEATURE_ENABLED_MASK, fpu_user_cfg.max_features); /* * Restore IA32_XSS. The same CPUID bit enumerates support @@ -840,6 +994,9 @@ void fpu__resume_cpu(void) wrmsrl(MSR_IA32_XSS, xfeatures_mask_supervisor() | xfeatures_mask_independent()); } + + if (fpu_state_size_dynamic()) + wrmsrl(MSR_IA32_XFD, current->thread.fpu.fpstate->xfd); } /* @@ -886,7 +1043,7 @@ void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr) * We should not ever be requesting features that we * have not enabled. */ - WARN_ONCE(!(xfeatures_mask_all & BIT_ULL(xfeature_nr)), + WARN_ONCE(!(fpu_kernel_cfg.max_features & BIT_ULL(xfeature_nr)), "get of unsupported state"); /* * This assumes the last 'xsave*' instruction to @@ -904,7 +1061,6 @@ void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr) return __raw_xsave_addr(xsave, xfeature_nr); } -EXPORT_SYMBOL_GPL(get_xsave_addr); #ifdef CONFIG_ARCH_HAS_PKEYS @@ -961,9 +1117,10 @@ static void copy_feature(bool from_xstate, struct membuf *to, void *xstate, } /** - * copy_xstate_to_uabi_buf - Copy kernel saved xstate to a UABI buffer + * __copy_xstate_to_uabi_buf - Copy kernel saved xstate to a UABI buffer * @to: membuf descriptor - * @tsk: The task from which to copy the saved xstate + * @fpstate: The fpstate buffer from which to copy + * @pkru_val: The PKRU value to store in the PKRU component * @copy_mode: The requested copy mode * * Converts from kernel XSAVE or XSAVES compacted format to UABI conforming @@ -972,14 +1129,15 @@ static void copy_feature(bool from_xstate, struct membuf *to, void *xstate, * * It supports partial copy but @to.pos always starts from zero. */ -void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk, - enum xstate_copy_mode copy_mode) +void __copy_xstate_to_uabi_buf(struct membuf to, struct fpstate *fpstate, + u32 pkru_val, enum xstate_copy_mode copy_mode) { const unsigned int off_mxcsr = offsetof(struct fxregs_state, mxcsr); - struct xregs_state *xsave = &tsk->thread.fpu.state.xsave; - struct xregs_state *xinit = &init_fpstate.xsave; + struct xregs_state *xinit = &init_fpstate.regs.xsave; + struct xregs_state *xsave = &fpstate->regs.xsave; struct xstate_header header; unsigned int zerofrom; + u64 mask; int i; memset(&header, 0, sizeof(header)); @@ -996,7 +1154,7 @@ void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk, break; case XSTATE_COPY_XSAVE: - header.xfeatures &= xfeatures_mask_uabi(); + header.xfeatures &= fpstate->user_xfeatures; break; } @@ -1033,17 +1191,15 @@ void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk, zerofrom = offsetof(struct xregs_state, extended_state_area); - for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) { - /* - * The ptrace buffer is in non-compacted XSAVE format. - * In non-compacted format disabled features still occupy - * state space, but there is no state to copy from in the - * compacted init_fpstate. The gap tracking will zero this - * later. - */ - if (!(xfeatures_mask_uabi() & BIT_ULL(i))) - continue; + /* + * The ptrace buffer is in non-compacted XSAVE format. In + * non-compacted format disabled features still occupy state space, + * but there is no state to copy from in the compacted + * init_fpstate. The gap tracking will zero these states. + */ + mask = fpstate->user_xfeatures; + for_each_extended_xfeature(i, mask) { /* * If there was a feature or alignment gap, zero the space * in the destination buffer. @@ -1055,10 +1211,9 @@ void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk, struct pkru_state pkru = {0}; /* * PKRU is not necessarily up to date in the - * thread's XSAVE buffer. Fill this part from the - * per-thread storage. + * XSAVE buffer. Use the provided value. */ - pkru.pkru = tsk->thread.pkru; + pkru.pkru = pkru_val; membuf_write(&to, &pkru, sizeof(pkru)); } else { copy_feature(header.xfeatures & BIT_ULL(i), &to, @@ -1078,6 +1233,25 @@ out: membuf_zero(&to, to.left); } +/** + * copy_xstate_to_uabi_buf - Copy kernel saved xstate to a UABI buffer + * @to: membuf descriptor + * @tsk: The task from which to copy the saved xstate + * @copy_mode: The requested copy mode + * + * Converts from kernel XSAVE or XSAVES compacted format to UABI conforming + * format, i.e. from the kernel internal hardware dependent storage format + * to the requested @mode. UABI XSTATE is always uncompacted! + * + * It supports partial copy but @to.pos always starts from zero. + */ +void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk, + enum xstate_copy_mode copy_mode) +{ + __copy_xstate_to_uabi_buf(to, tsk->thread.fpu.fpstate, + tsk->thread.pkru, copy_mode); +} + static int copy_from_buffer(void *dst, unsigned int offset, unsigned int size, const void *kbuf, const void __user *ubuf) { @@ -1091,9 +1265,10 @@ static int copy_from_buffer(void *dst, unsigned int offset, unsigned int size, } -static int copy_uabi_to_xstate(struct xregs_state *xsave, const void *kbuf, +static int copy_uabi_to_xstate(struct fpstate *fpstate, const void *kbuf, const void __user *ubuf) { + struct xregs_state *xsave = &fpstate->regs.xsave; unsigned int offset, size; struct xstate_header hdr; u64 mask; @@ -1103,7 +1278,7 @@ static int copy_uabi_to_xstate(struct xregs_state *xsave, const void *kbuf, if (copy_from_buffer(&hdr, offset, sizeof(hdr), kbuf, ubuf)) return -EFAULT; - if (validate_user_xstate_header(&hdr)) + if (validate_user_xstate_header(&hdr, fpstate)) return -EINVAL; /* Validate MXCSR when any of the related features is in use */ @@ -1156,12 +1331,11 @@ static int copy_uabi_to_xstate(struct xregs_state *xsave, const void *kbuf, /* * Convert from a ptrace standard-format kernel buffer to kernel XSAVE[S] - * format and copy to the target thread. This is called from - * xstateregs_set(). + * format and copy to the target thread. Used by ptrace and KVM. */ -int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf) +int copy_uabi_from_kernel_to_xstate(struct fpstate *fpstate, const void *kbuf) { - return copy_uabi_to_xstate(xsave, kbuf, NULL); + return copy_uabi_to_xstate(fpstate, kbuf, NULL); } /* @@ -1169,26 +1343,20 @@ int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf) * XSAVE[S] format and copy to the target thread. This is called from the * sigreturn() and rt_sigreturn() system calls. */ -int copy_sigframe_from_user_to_xstate(struct xregs_state *xsave, +int copy_sigframe_from_user_to_xstate(struct fpstate *fpstate, const void __user *ubuf) { - return copy_uabi_to_xstate(xsave, NULL, ubuf); + return copy_uabi_to_xstate(fpstate, NULL, ubuf); } -static bool validate_xsaves_xrstors(u64 mask) +static bool validate_independent_components(u64 mask) { u64 xchk; if (WARN_ON_FPU(!cpu_feature_enabled(X86_FEATURE_XSAVES))) return false; - /* - * Validate that this is either a task->fpstate related component - * subset or an independent one. - */ - if (mask & xfeatures_mask_independent()) - xchk = ~xfeatures_mask_independent(); - else - xchk = ~xfeatures_mask_all; + + xchk = ~xfeatures_mask_independent(); if (WARN_ON_ONCE(!mask || mask & xchk)) return false; @@ -1206,14 +1374,13 @@ static bool validate_xsaves_xrstors(u64 mask) * buffer should be zeroed otherwise a consecutive XRSTORS from that buffer * can #GP. * - * The feature mask must either be a subset of the independent features or - * a subset of the task->fpstate related features. + * The feature mask must be a subset of the independent features. */ void xsaves(struct xregs_state *xstate, u64 mask) { int err; - if (!validate_xsaves_xrstors(mask)) + if (!validate_independent_components(mask)) return; XSTATE_OP(XSAVES, xstate, (u32)mask, (u32)(mask >> 32), err); @@ -1231,20 +1398,379 @@ void xsaves(struct xregs_state *xstate, u64 mask) * Proper usage is to restore the state which was saved with * xsaves() into @xstate. * - * The feature mask must either be a subset of the independent features or - * a subset of the task->fpstate related features. + * The feature mask must be a subset of the independent features. */ void xrstors(struct xregs_state *xstate, u64 mask) { int err; - if (!validate_xsaves_xrstors(mask)) + if (!validate_independent_components(mask)) return; XSTATE_OP(XRSTORS, xstate, (u32)mask, (u32)(mask >> 32), err); WARN_ON_ONCE(err); } +#if IS_ENABLED(CONFIG_KVM) +void fpstate_clear_xstate_component(struct fpstate *fps, unsigned int xfeature) +{ + void *addr = get_xsave_addr(&fps->regs.xsave, xfeature); + + if (addr) + memset(addr, 0, xstate_sizes[xfeature]); +} +EXPORT_SYMBOL_GPL(fpstate_clear_xstate_component); +#endif + +#ifdef CONFIG_X86_64 + +#ifdef CONFIG_X86_DEBUG_FPU +/* + * Ensure that a subsequent XSAVE* or XRSTOR* instruction with RFBM=@mask + * can safely operate on the @fpstate buffer. + */ +static bool xstate_op_valid(struct fpstate *fpstate, u64 mask, bool rstor) +{ + u64 xfd = __this_cpu_read(xfd_state); + + if (fpstate->xfd == xfd) + return true; + + /* + * The XFD MSR does not match fpstate->xfd. That's invalid when + * the passed in fpstate is current's fpstate. + */ + if (fpstate->xfd == current->thread.fpu.fpstate->xfd) + return false; + + /* + * XRSTOR(S) from init_fpstate are always correct as it will just + * bring all components into init state and not read from the + * buffer. XSAVE(S) raises #PF after init. + */ + if (fpstate == &init_fpstate) + return rstor; + + /* + * XSAVE(S): clone(), fpu_swap_kvm_fpu() + * XRSTORS(S): fpu_swap_kvm_fpu() + */ + + /* + * No XSAVE/XRSTOR instructions (except XSAVE itself) touch + * the buffer area for XFD-disabled state components. + */ + mask &= ~xfd; + + /* + * Remove features which are valid in fpstate. They + * have space allocated in fpstate. + */ + mask &= ~fpstate->xfeatures; + + /* + * Any remaining state components in 'mask' might be written + * by XSAVE/XRSTOR. Fail validation it found. + */ + return !mask; +} + +void xfd_validate_state(struct fpstate *fpstate, u64 mask, bool rstor) +{ + WARN_ON_ONCE(!xstate_op_valid(fpstate, mask, rstor)); +} +#endif /* CONFIG_X86_DEBUG_FPU */ + +static int __init xfd_update_static_branch(void) +{ + /* + * If init_fpstate.xfd has bits set then dynamic features are + * available and the dynamic sizing must be enabled. + */ + if (init_fpstate.xfd) + static_branch_enable(&__fpu_state_size_dynamic); + return 0; +} +arch_initcall(xfd_update_static_branch) + +void fpstate_free(struct fpu *fpu) +{ + if (fpu->fpstate && fpu->fpstate != &fpu->__fpstate) + vfree(fpu->fpstate); +} + +/** + * fpu_install_fpstate - Update the active fpstate in the FPU + * + * @fpu: A struct fpu * pointer + * @newfps: A struct fpstate * pointer + * + * Returns: A null pointer if the last active fpstate is the embedded + * one or the new fpstate is already installed; + * otherwise, a pointer to the old fpstate which has to + * be freed by the caller. + */ +static struct fpstate *fpu_install_fpstate(struct fpu *fpu, + struct fpstate *newfps) +{ + struct fpstate *oldfps = fpu->fpstate; + + if (fpu->fpstate == newfps) + return NULL; + + fpu->fpstate = newfps; + return oldfps != &fpu->__fpstate ? oldfps : NULL; +} + +/** + * fpstate_realloc - Reallocate struct fpstate for the requested new features + * + * @xfeatures: A bitmap of xstate features which extend the enabled features + * of that task + * @ksize: The required size for the kernel buffer + * @usize: The required size for user space buffers + * + * Note vs. vmalloc(): If the task with a vzalloc()-allocated buffer + * terminates quickly, vfree()-induced IPIs may be a concern, but tasks + * with large states are likely to live longer. + * + * Returns: 0 on success, -ENOMEM on allocation error. + */ +static int fpstate_realloc(u64 xfeatures, unsigned int ksize, + unsigned int usize) +{ + struct fpu *fpu = ¤t->thread.fpu; + struct fpstate *curfps, *newfps = NULL; + unsigned int fpsize; + + curfps = fpu->fpstate; + fpsize = ksize + ALIGN(offsetof(struct fpstate, regs), 64); + + newfps = vzalloc(fpsize); + if (!newfps) + return -ENOMEM; + newfps->size = ksize; + newfps->user_size = usize; + newfps->is_valloc = true; + + fpregs_lock(); + /* + * Ensure that the current state is in the registers before + * swapping fpstate as that might invalidate it due to layout + * changes. + */ + if (test_thread_flag(TIF_NEED_FPU_LOAD)) + fpregs_restore_userregs(); + + newfps->xfeatures = curfps->xfeatures | xfeatures; + newfps->user_xfeatures = curfps->user_xfeatures | xfeatures; + newfps->xfd = curfps->xfd & ~xfeatures; + + curfps = fpu_install_fpstate(fpu, newfps); + + /* Do the final updates within the locked region */ + xstate_init_xcomp_bv(&newfps->regs.xsave, newfps->xfeatures); + xfd_update_state(newfps); + + fpregs_unlock(); + + vfree(curfps); + return 0; +} + +static int validate_sigaltstack(unsigned int usize) +{ + struct task_struct *thread, *leader = current->group_leader; + unsigned long framesize = get_sigframe_size(); + + lockdep_assert_held(¤t->sighand->siglock); + + /* get_sigframe_size() is based on fpu_user_cfg.max_size */ + framesize -= fpu_user_cfg.max_size; + framesize += usize; + for_each_thread(leader, thread) { + if (thread->sas_ss_size && thread->sas_ss_size < framesize) + return -ENOSPC; + } + return 0; +} + +static int __xstate_request_perm(u64 permitted, u64 requested) +{ + /* + * This deliberately does not exclude !XSAVES as we still might + * decide to optionally context switch XCR0 or talk the silicon + * vendors into extending XFD for the pre AMX states, especially + * AVX512. + */ + bool compacted = cpu_feature_enabled(X86_FEATURE_XSAVES); + struct fpu *fpu = ¤t->group_leader->thread.fpu; + unsigned int ksize, usize; + u64 mask; + int ret; + + /* Check whether fully enabled */ + if ((permitted & requested) == requested) + return 0; + + /* Calculate the resulting kernel state size */ + mask = permitted | requested; + ksize = xstate_calculate_size(mask, compacted); + + /* Calculate the resulting user state size */ + mask &= XFEATURE_MASK_USER_SUPPORTED; + usize = xstate_calculate_size(mask, false); + + ret = validate_sigaltstack(usize); + if (ret) + return ret; + + /* Pairs with the READ_ONCE() in xstate_get_group_perm() */ + WRITE_ONCE(fpu->perm.__state_perm, requested); + /* Protected by sighand lock */ + fpu->perm.__state_size = ksize; + fpu->perm.__user_state_size = usize; + return ret; +} + +/* + * Permissions array to map facilities with more than one component + */ +static const u64 xstate_prctl_req[XFEATURE_MAX] = { + [XFEATURE_XTILE_DATA] = XFEATURE_MASK_XTILE_DATA, +}; + +static int xstate_request_perm(unsigned long idx) +{ + u64 permitted, requested; + int ret; + + if (idx >= XFEATURE_MAX) + return -EINVAL; + + /* + * Look up the facility mask which can require more than + * one xstate component. + */ + idx = array_index_nospec(idx, ARRAY_SIZE(xstate_prctl_req)); + requested = xstate_prctl_req[idx]; + if (!requested) + return -EOPNOTSUPP; + + if ((fpu_user_cfg.max_features & requested) != requested) + return -EOPNOTSUPP; + + /* Lockless quick check */ + permitted = xstate_get_host_group_perm(); + if ((permitted & requested) == requested) + return 0; + + /* Protect against concurrent modifications */ + spin_lock_irq(¤t->sighand->siglock); + permitted = xstate_get_host_group_perm(); + ret = __xstate_request_perm(permitted, requested); + spin_unlock_irq(¤t->sighand->siglock); + return ret; +} + +int xfd_enable_feature(u64 xfd_err) +{ + u64 xfd_event = xfd_err & XFEATURE_MASK_USER_DYNAMIC; + unsigned int ksize, usize; + struct fpu *fpu; + + if (!xfd_event) { + pr_err_once("XFD: Invalid xfd error: %016llx\n", xfd_err); + return 0; + } + + /* Protect against concurrent modifications */ + spin_lock_irq(¤t->sighand->siglock); + + /* If not permitted let it die */ + if ((xstate_get_host_group_perm() & xfd_event) != xfd_event) { + spin_unlock_irq(¤t->sighand->siglock); + return -EPERM; + } + + fpu = ¤t->group_leader->thread.fpu; + ksize = fpu->perm.__state_size; + usize = fpu->perm.__user_state_size; + /* + * The feature is permitted. State size is sufficient. Dropping + * the lock is safe here even if more features are added from + * another task, the retrieved buffer sizes are valid for the + * currently requested feature(s). + */ + spin_unlock_irq(¤t->sighand->siglock); + + /* + * Try to allocate a new fpstate. If that fails there is no way + * out. + */ + if (fpstate_realloc(xfd_event, ksize, usize)) + return -EFAULT; + return 0; +} +#else /* CONFIG_X86_64 */ +static inline int xstate_request_perm(unsigned long idx) +{ + return -EPERM; +} +#endif /* !CONFIG_X86_64 */ + +/** + * fpu_xstate_prctl - xstate permission operations + * @tsk: Redundant pointer to current + * @option: A subfunction of arch_prctl() + * @arg2: option argument + * Return: 0 if successful; otherwise, an error code + * + * Option arguments: + * + * ARCH_GET_XCOMP_SUPP: Pointer to user space u64 to store the info + * ARCH_GET_XCOMP_PERM: Pointer to user space u64 to store the info + * ARCH_REQ_XCOMP_PERM: Facility number requested + * + * For facilities which require more than one XSTATE component, the request + * must be the highest state component number related to that facility, + * e.g. for AMX which requires XFEATURE_XTILE_CFG(17) and + * XFEATURE_XTILE_DATA(18) this would be XFEATURE_XTILE_DATA(18). + */ +long fpu_xstate_prctl(struct task_struct *tsk, int option, unsigned long arg2) +{ + u64 __user *uptr = (u64 __user *)arg2; + u64 permitted, supported; + unsigned long idx = arg2; + + if (tsk != current) + return -EPERM; + + switch (option) { + case ARCH_GET_XCOMP_SUPP: + supported = fpu_user_cfg.max_features | fpu_user_cfg.legacy_features; + return put_user(supported, uptr); + + case ARCH_GET_XCOMP_PERM: + /* + * Lockless snapshot as it can also change right after the + * dropping the lock. + */ + permitted = xstate_get_host_group_perm(); + permitted &= XFEATURE_MASK_USER_SUPPORTED; + return put_user(permitted, uptr); + + case ARCH_REQ_XCOMP_PERM: + if (!IS_ENABLED(CONFIG_X86_64)) + return -EOPNOTSUPP; + + return xstate_request_perm(idx); + + default: + return -EINVAL; + } +} + #ifdef CONFIG_PROC_PID_ARCH_STATUS /* * Report the amount of time elapsed in millisecond since last AVX512 diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h new file mode 100644 index 0000000..e18210d --- /dev/null +++ b/arch/x86/kernel/fpu/xstate.h @@ -0,0 +1,278 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __X86_KERNEL_FPU_XSTATE_H +#define __X86_KERNEL_FPU_XSTATE_H + +#include +#include + +#ifdef CONFIG_X86_64 +DECLARE_PER_CPU(u64, xfd_state); +#endif + +static inline void xstate_init_xcomp_bv(struct xregs_state *xsave, u64 mask) +{ + /* + * XRSTORS requires these bits set in xcomp_bv, or it will + * trigger #GP: + */ + if (cpu_feature_enabled(X86_FEATURE_XSAVES)) + xsave->header.xcomp_bv = mask | XCOMP_BV_COMPACTED_FORMAT; +} + +static inline u64 xstate_get_host_group_perm(void) +{ + /* Pairs with WRITE_ONCE() in xstate_request_perm() */ + return READ_ONCE(current->group_leader->thread.fpu.perm.__state_perm); +} + +enum xstate_copy_mode { + XSTATE_COPY_FP, + XSTATE_COPY_FX, + XSTATE_COPY_XSAVE, +}; + +struct membuf; +extern void __copy_xstate_to_uabi_buf(struct membuf to, struct fpstate *fpstate, + u32 pkru_val, enum xstate_copy_mode copy_mode); +extern void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk, + enum xstate_copy_mode mode); +extern int copy_uabi_from_kernel_to_xstate(struct fpstate *fpstate, const void *kbuf); +extern int copy_sigframe_from_user_to_xstate(struct fpstate *fpstate, const void __user *ubuf); + + +extern void fpu__init_cpu_xstate(void); +extern void fpu__init_system_xstate(unsigned int legacy_size); + +extern void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr); + +static inline u64 xfeatures_mask_supervisor(void) +{ + return fpu_kernel_cfg.max_features & XFEATURE_MASK_SUPERVISOR_SUPPORTED; +} + +static inline u64 xfeatures_mask_independent(void) +{ + if (!cpu_feature_enabled(X86_FEATURE_ARCH_LBR)) + return XFEATURE_MASK_INDEPENDENT & ~XFEATURE_MASK_LBR; + + return XFEATURE_MASK_INDEPENDENT; +} + +/* XSAVE/XRSTOR wrapper functions */ + +#ifdef CONFIG_X86_64 +#define REX_PREFIX "0x48, " +#else +#define REX_PREFIX +#endif + +/* These macros all use (%edi)/(%rdi) as the single memory argument. */ +#define XSAVE ".byte " REX_PREFIX "0x0f,0xae,0x27" +#define XSAVEOPT ".byte " REX_PREFIX "0x0f,0xae,0x37" +#define XSAVES ".byte " REX_PREFIX "0x0f,0xc7,0x2f" +#define XRSTOR ".byte " REX_PREFIX "0x0f,0xae,0x2f" +#define XRSTORS ".byte " REX_PREFIX "0x0f,0xc7,0x1f" + +/* + * After this @err contains 0 on success or the trap number when the + * operation raises an exception. + */ +#define XSTATE_OP(op, st, lmask, hmask, err) \ + asm volatile("1:" op "\n\t" \ + "xor %[err], %[err]\n" \ + "2:\n\t" \ + _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_FAULT_MCE_SAFE) \ + : [err] "=a" (err) \ + : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \ + : "memory") + +/* + * If XSAVES is enabled, it replaces XSAVEOPT because it supports a compact + * format and supervisor states in addition to modified optimization in + * XSAVEOPT. + * + * Otherwise, if XSAVEOPT is enabled, XSAVEOPT replaces XSAVE because XSAVEOPT + * supports modified optimization which is not supported by XSAVE. + * + * We use XSAVE as a fallback. + * + * The 661 label is defined in the ALTERNATIVE* macros as the address of the + * original instruction which gets replaced. We need to use it here as the + * address of the instruction where we might get an exception at. + */ +#define XSTATE_XSAVE(st, lmask, hmask, err) \ + asm volatile(ALTERNATIVE_2(XSAVE, \ + XSAVEOPT, X86_FEATURE_XSAVEOPT, \ + XSAVES, X86_FEATURE_XSAVES) \ + "\n" \ + "xor %[err], %[err]\n" \ + "3:\n" \ + ".pushsection .fixup,\"ax\"\n" \ + "4: movl $-2, %[err]\n" \ + "jmp 3b\n" \ + ".popsection\n" \ + _ASM_EXTABLE(661b, 4b) \ + : [err] "=r" (err) \ + : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \ + : "memory") + +/* + * Use XRSTORS to restore context if it is enabled. XRSTORS supports compact + * XSAVE area format. + */ +#define XSTATE_XRESTORE(st, lmask, hmask) \ + asm volatile(ALTERNATIVE(XRSTOR, \ + XRSTORS, X86_FEATURE_XSAVES) \ + "\n" \ + "3:\n" \ + _ASM_EXTABLE_TYPE(661b, 3b, EX_TYPE_FPU_RESTORE) \ + : \ + : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \ + : "memory") + +#if defined(CONFIG_X86_64) && defined(CONFIG_X86_DEBUG_FPU) +extern void xfd_validate_state(struct fpstate *fpstate, u64 mask, bool rstor); +#else +static inline void xfd_validate_state(struct fpstate *fpstate, u64 mask, bool rstor) { } +#endif + +#ifdef CONFIG_X86_64 +static inline void xfd_update_state(struct fpstate *fpstate) +{ + if (fpu_state_size_dynamic()) { + u64 xfd = fpstate->xfd; + + if (__this_cpu_read(xfd_state) != xfd) { + wrmsrl(MSR_IA32_XFD, xfd); + __this_cpu_write(xfd_state, xfd); + } + } +} +#else +static inline void xfd_update_state(struct fpstate *fpstate) { } +#endif + +/* + * Save processor xstate to xsave area. + * + * Uses either XSAVE or XSAVEOPT or XSAVES depending on the CPU features + * and command line options. The choice is permanent until the next reboot. + */ +static inline void os_xsave(struct fpstate *fpstate) +{ + u64 mask = fpstate->xfeatures; + u32 lmask = mask; + u32 hmask = mask >> 32; + int err; + + WARN_ON_FPU(!alternatives_patched); + xfd_validate_state(fpstate, mask, false); + + XSTATE_XSAVE(&fpstate->regs.xsave, lmask, hmask, err); + + /* We should never fault when copying to a kernel buffer: */ + WARN_ON_FPU(err); +} + +/* + * Restore processor xstate from xsave area. + * + * Uses XRSTORS when XSAVES is used, XRSTOR otherwise. + */ +static inline void os_xrstor(struct fpstate *fpstate, u64 mask) +{ + u32 lmask = mask; + u32 hmask = mask >> 32; + + xfd_validate_state(fpstate, mask, true); + XSTATE_XRESTORE(&fpstate->regs.xsave, lmask, hmask); +} + +/* Restore of supervisor state. Does not require XFD */ +static inline void os_xrstor_supervisor(struct fpstate *fpstate) +{ + u64 mask = xfeatures_mask_supervisor(); + u32 lmask = mask; + u32 hmask = mask >> 32; + + XSTATE_XRESTORE(&fpstate->regs.xsave, lmask, hmask); +} + +/* + * Save xstate to user space xsave area. + * + * We don't use modified optimization because xrstor/xrstors might track + * a different application. + * + * We don't use compacted format xsave area for backward compatibility for + * old applications which don't understand the compacted format of the + * xsave area. + * + * The caller has to zero buf::header before calling this because XSAVE* + * does not touch the reserved fields in the header. + */ +static inline int xsave_to_user_sigframe(struct xregs_state __user *buf) +{ + /* + * Include the features which are not xsaved/rstored by the kernel + * internally, e.g. PKRU. That's user space ABI and also required + * to allow the signal handler to modify PKRU. + */ + struct fpstate *fpstate = current->thread.fpu.fpstate; + u64 mask = fpstate->user_xfeatures; + u32 lmask = mask; + u32 hmask = mask >> 32; + int err; + + xfd_validate_state(fpstate, mask, false); + + stac(); + XSTATE_OP(XSAVE, buf, lmask, hmask, err); + clac(); + + return err; +} + +/* + * Restore xstate from user space xsave area. + */ +static inline int xrstor_from_user_sigframe(struct xregs_state __user *buf, u64 mask) +{ + struct xregs_state *xstate = ((__force struct xregs_state *)buf); + u32 lmask = mask; + u32 hmask = mask >> 32; + int err; + + xfd_validate_state(current->thread.fpu.fpstate, mask, true); + + stac(); + XSTATE_OP(XRSTOR, xstate, lmask, hmask, err); + clac(); + + return err; +} + +/* + * Restore xstate from kernel space xsave area, return an error code instead of + * an exception. + */ +static inline int os_xrstor_safe(struct fpstate *fpstate, u64 mask) +{ + struct xregs_state *xstate = &fpstate->regs.xsave; + u32 lmask = mask; + u32 hmask = mask >> 32; + int err; + + /* Ensure that XFD is up to date */ + xfd_update_state(fpstate); + + if (cpu_feature_enabled(X86_FEATURE_XSAVES)) + XSTATE_OP(XRSTORS, xstate, lmask, hmask, err); + else + XSTATE_OP(XRSTOR, xstate, lmask, hmask, err); + + return err; +} + + +#endif diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 8fb6bd4..eb470be 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -30,7 +30,9 @@ #include #include #include -#include +#include +#include +#include #include #include #include @@ -88,8 +90,19 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) #ifdef CONFIG_VM86 dst->thread.vm86 = NULL; #endif - return fpu_clone(dst); + /* Drop the copied pointer to current's fpstate */ + dst->thread.fpu.fpstate = NULL; + + return 0; +} + +#ifdef CONFIG_X86_64 +void arch_release_task_struct(struct task_struct *tsk) +{ + if (fpu_state_size_dynamic()) + fpstate_free(&tsk->thread.fpu); } +#endif /* * Free thread data structures etc.. @@ -155,6 +168,8 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg, frame->flags = X86_EFLAGS_FIXED; #endif + fpu_clone(p, clone_flags); + /* Kernel thread ? */ if (unlikely(p->flags & PF_KTHREAD)) { p->thread.pkru = pkru_get_init_value(); @@ -962,13 +977,17 @@ unsigned long __get_wchan(struct task_struct *p) } long do_arch_prctl_common(struct task_struct *task, int option, - unsigned long cpuid_enabled) + unsigned long arg2) { switch (option) { case ARCH_GET_CPUID: return get_cpuid_mode(); case ARCH_SET_CPUID: - return set_cpuid_mode(task, cpuid_enabled); + return set_cpuid_mode(task, arg2); + case ARCH_GET_XCOMP_SUPP: + case ARCH_GET_XCOMP_PERM: + case ARCH_REQ_XCOMP_PERM: + return fpu_xstate_prctl(task, option, arg2); } return -EINVAL; diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index 4f2f54e..26edb1c 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -41,7 +41,7 @@ #include #include -#include +#include #include #include @@ -160,7 +160,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) struct thread_struct *prev = &prev_p->thread, *next = &next_p->thread; struct fpu *prev_fpu = &prev->fpu; - struct fpu *next_fpu = &next->fpu; int cpu = smp_processor_id(); /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */ @@ -213,7 +212,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) this_cpu_write(current_task, next_p); - switch_fpu_finish(next_fpu); + switch_fpu_finish(); /* Load the Intel cache allocation PQR MSR. */ resctrl_sched_in(); diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index ec0d836..3402ede 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -42,7 +42,7 @@ #include #include -#include +#include #include #include #include @@ -559,7 +559,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) struct thread_struct *prev = &prev_p->thread; struct thread_struct *next = &next_p->thread; struct fpu *prev_fpu = &prev->fpu; - struct fpu *next_fpu = &next->fpu; int cpu = smp_processor_id(); WARN_ON_ONCE(IS_ENABLED(CONFIG_DEBUG_ENTRY) && @@ -620,7 +619,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) this_cpu_write(current_task, next_p); this_cpu_write(cpu_current_top_of_stack, task_top_of_stack(next_p)); - switch_fpu_finish(next_fpu); + switch_fpu_finish(); /* Reload sp0. */ update_task_stack(next_p); diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 4c208ea..6d2244c 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -29,9 +29,9 @@ #include #include -#include #include #include +#include #include #include #include diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index a6895e4..50c773c 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -23,7 +23,7 @@ #include #include #include -#include +#include #include #include #include diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index f4d21e4..ec71e06 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -30,8 +31,8 @@ #include #include -#include #include +#include #include #include #include @@ -41,6 +42,7 @@ #include #include #include +#include #endif /* CONFIG_X86_64 */ #include @@ -79,9 +81,9 @@ static void force_valid_ss(struct pt_regs *regs) # define CONTEXT_COPY_SIZE sizeof(struct sigcontext) #endif -static int restore_sigcontext(struct pt_regs *regs, - struct sigcontext __user *usc, - unsigned long uc_flags) +static bool restore_sigcontext(struct pt_regs *regs, + struct sigcontext __user *usc, + unsigned long uc_flags) { struct sigcontext sc; @@ -89,7 +91,7 @@ static int restore_sigcontext(struct pt_regs *regs, current->restart_block.fn = do_no_restart_syscall; if (copy_from_user(&sc, usc, CONTEXT_COPY_SIZE)) - return -EFAULT; + return false; #ifdef CONFIG_X86_32 set_user_gs(regs, sc.gs); @@ -244,7 +246,6 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, unsigned long math_size = 0; unsigned long sp = regs->sp; unsigned long buf_fx = 0; - int ret; /* redzone */ if (IS_ENABLED(CONFIG_X86_64)) @@ -292,8 +293,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, } /* save i387 and extended state */ - ret = copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size); - if (ret < 0) + if (!copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size)) return (void __user *)-1L; return (void __user *)sp; @@ -643,7 +643,7 @@ SYSCALL_DEFINE0(sigreturn) * x86_32 has no uc_flags bits relevant to restore_sigcontext. * Save a few cycles by skipping the __get_user. */ - if (restore_sigcontext(regs, &frame->sc, 0)) + if (!restore_sigcontext(regs, &frame->sc, 0)) goto badframe; return regs->ax; @@ -671,7 +671,7 @@ SYSCALL_DEFINE0(rt_sigreturn) set_current_blocked(&set); - if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) + if (!restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) goto badframe; if (restore_altstack(&frame->uc.uc_stack)) @@ -721,12 +721,15 @@ badframe: /* max_frame_size tells userspace the worst case signal stack size. */ static unsigned long __ro_after_init max_frame_size; +static unsigned int __ro_after_init fpu_default_state_size; void __init init_sigframe_size(void) { + fpu_default_state_size = fpu__get_fpstate_size(); + max_frame_size = MAX_FRAME_SIGINFO_UCTXT_SIZE + MAX_FRAME_PADDING; - max_frame_size += fpu__get_fpstate_size() + MAX_XSAVE_PADDING; + max_frame_size += fpu_default_state_size + MAX_XSAVE_PADDING; /* Userspace expects an aligned size. */ max_frame_size = round_up(max_frame_size, FRAME_ALIGNMENT); @@ -910,6 +913,62 @@ void signal_fault(struct pt_regs *regs, void __user *frame, char *where) force_sig(SIGSEGV); } +#ifdef CONFIG_DYNAMIC_SIGFRAME +#ifdef CONFIG_STRICT_SIGALTSTACK_SIZE +static bool strict_sigaltstack_size __ro_after_init = true; +#else +static bool strict_sigaltstack_size __ro_after_init = false; +#endif + +static int __init strict_sas_size(char *arg) +{ + return kstrtobool(arg, &strict_sigaltstack_size); +} +__setup("strict_sas_size", strict_sas_size); + +/* + * MINSIGSTKSZ is 2048 and can't be changed despite the fact that AVX512 + * exceeds that size already. As such programs might never use the + * sigaltstack they just continued to work. While always checking against + * the real size would be correct, this might be considered a regression. + * + * Therefore avoid the sanity check, unless enforced by kernel + * configuration or command line option. + * + * When dynamic FPU features are supported, the check is also enforced when + * the task has permissions to use dynamic features. Tasks which have no + * permission are checked against the size of the non-dynamic feature set + * if strict checking is enabled. This avoids forcing all tasks on the + * system to allocate large sigaltstacks even if they are never going + * to use a dynamic feature. As this is serialized via sighand::siglock + * any permission request for a dynamic feature either happened already + * or will see the newly install sigaltstack size in the permission checks. + */ +bool sigaltstack_size_valid(size_t ss_size) +{ + unsigned long fsize = max_frame_size - fpu_default_state_size; + u64 mask; + + lockdep_assert_held(¤t->sighand->siglock); + + if (!fpu_state_size_dynamic() && !strict_sigaltstack_size) + return true; + + fsize += current->group_leader->thread.fpu.perm.__user_state_size; + if (likely(ss_size > fsize)) + return true; + + if (strict_sigaltstack_size) + return ss_size > fsize; + + mask = current->group_leader->thread.fpu.perm.__state_perm; + if (mask & XFEATURE_MASK_USER_DYNAMIC) + return ss_size > fsize; + + return true; +} +#endif /* CONFIG_DYNAMIC_SIGFRAME */ + #ifdef CONFIG_X86_X32_ABI COMPAT_SYSCALL_DEFINE0(x32_rt_sigreturn) { @@ -929,7 +988,7 @@ COMPAT_SYSCALL_DEFINE0(x32_rt_sigreturn) set_current_blocked(&set); - if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) + if (!restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) goto badframe; if (compat_restore_altstack(&frame->uc.uc_stack)) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index f80f459..959599a 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -70,7 +70,7 @@ #include #include #include -#include +#include #include #include #include diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index a588009..6ca1454 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -48,7 +48,7 @@ #include #include #include -#include +#include #include #include #include @@ -1108,10 +1108,48 @@ DEFINE_IDTENTRY(exc_spurious_interrupt_bug) */ } +static bool handle_xfd_event(struct pt_regs *regs) +{ + u64 xfd_err; + int err; + + if (!IS_ENABLED(CONFIG_X86_64) || !cpu_feature_enabled(X86_FEATURE_XFD)) + return false; + + rdmsrl(MSR_IA32_XFD_ERR, xfd_err); + if (!xfd_err) + return false; + + wrmsrl(MSR_IA32_XFD_ERR, 0); + + /* Die if that happens in kernel space */ + if (WARN_ON(!user_mode(regs))) + return false; + + local_irq_enable(); + + err = xfd_enable_feature(xfd_err); + + switch (err) { + case -EPERM: + force_sig_fault(SIGILL, ILL_ILLOPC, error_get_trap_addr(regs)); + break; + case -EFAULT: + force_sig(SIGSEGV); + break; + } + + local_irq_disable(); + return true; +} + DEFINE_IDTENTRY(exc_device_not_available) { unsigned long cr0 = read_cr0(); + if (handle_xfd_event(regs)) + return; + #ifdef CONFIG_MATH_EMULATION if (!boot_cpu_has(X86_FEATURE_FPU) && (cr0 & X86_CR0_EM)) { struct math_emu_info info = { }; diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 7e34d71..5847b05 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -17,10 +17,10 @@ #include #include #include -#include #include #include +#include #include "x86.h" #include "svm.h" diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 9896850..f39c87d 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -36,6 +36,7 @@ #include #include #include +#include #include #include "trace.h" @@ -1346,10 +1347,10 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu) /* * SEV-ES guests maintain an encrypted version of their FPU * state which is restored and saved on VMRUN and VMEXIT. - * Free the fpu structure to prevent KVM from attempting to - * access the FPU state. + * Mark vcpu->arch.guest_fpu->fpstate as scratch so it won't + * do xsave/xrstor on it. */ - kvm_free_guest_fpu(vcpu); + fpstate_set_confidential(&vcpu->arch.guest_fpu); } err = avic_init_vcpu(svm); diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 7d595ef..fb9e4ac 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -35,7 +35,7 @@ #include #include #include -#include +#include #include #include #include diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index bfe0de3..2686f2e 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -68,7 +68,9 @@ #include #include #include -#include /* Ugh! */ +#include +#include +#include #include #include #include @@ -293,8 +295,6 @@ u64 __read_mostly host_xcr0; u64 __read_mostly supported_xcr0; EXPORT_SYMBOL_GPL(supported_xcr0); -static struct kmem_cache *x86_fpu_cache; - static struct kmem_cache *x86_emulator_cache; /* @@ -4700,144 +4700,27 @@ static int kvm_vcpu_ioctl_x86_set_debugregs(struct kvm_vcpu *vcpu, return 0; } -#define XSTATE_COMPACTION_ENABLED (1ULL << 63) - -static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu) -{ - struct xregs_state *xsave = &vcpu->arch.guest_fpu->state.xsave; - u64 xstate_bv = xsave->header.xfeatures; - u64 valid; - - /* - * Copy legacy XSAVE area, to avoid complications with CPUID - * leaves 0 and 1 in the loop below. - */ - memcpy(dest, xsave, XSAVE_HDR_OFFSET); - - /* Set XSTATE_BV */ - xstate_bv &= vcpu->arch.guest_supported_xcr0 | XFEATURE_MASK_FPSSE; - *(u64 *)(dest + XSAVE_HDR_OFFSET) = xstate_bv; - - /* - * Copy each region from the possibly compacted offset to the - * non-compacted offset. - */ - valid = xstate_bv & ~XFEATURE_MASK_FPSSE; - while (valid) { - u32 size, offset, ecx, edx; - u64 xfeature_mask = valid & -valid; - int xfeature_nr = fls64(xfeature_mask) - 1; - void *src; - - cpuid_count(XSTATE_CPUID, xfeature_nr, - &size, &offset, &ecx, &edx); - - if (xfeature_nr == XFEATURE_PKRU) { - memcpy(dest + offset, &vcpu->arch.pkru, - sizeof(vcpu->arch.pkru)); - } else { - src = get_xsave_addr(xsave, xfeature_nr); - if (src) - memcpy(dest + offset, src, size); - } - - valid -= xfeature_mask; - } -} - -static void load_xsave(struct kvm_vcpu *vcpu, u8 *src) -{ - struct xregs_state *xsave = &vcpu->arch.guest_fpu->state.xsave; - u64 xstate_bv = *(u64 *)(src + XSAVE_HDR_OFFSET); - u64 valid; - - /* - * Copy legacy XSAVE area, to avoid complications with CPUID - * leaves 0 and 1 in the loop below. - */ - memcpy(xsave, src, XSAVE_HDR_OFFSET); - - /* Set XSTATE_BV and possibly XCOMP_BV. */ - xsave->header.xfeatures = xstate_bv; - if (boot_cpu_has(X86_FEATURE_XSAVES)) - xsave->header.xcomp_bv = host_xcr0 | XSTATE_COMPACTION_ENABLED; - - /* - * Copy each region from the non-compacted offset to the - * possibly compacted offset. - */ - valid = xstate_bv & ~XFEATURE_MASK_FPSSE; - while (valid) { - u32 size, offset, ecx, edx; - u64 xfeature_mask = valid & -valid; - int xfeature_nr = fls64(xfeature_mask) - 1; - - cpuid_count(XSTATE_CPUID, xfeature_nr, - &size, &offset, &ecx, &edx); - - if (xfeature_nr == XFEATURE_PKRU) { - memcpy(&vcpu->arch.pkru, src + offset, - sizeof(vcpu->arch.pkru)); - } else { - void *dest = get_xsave_addr(xsave, xfeature_nr); - - if (dest) - memcpy(dest, src + offset, size); - } - - valid -= xfeature_mask; - } -} - static void kvm_vcpu_ioctl_x86_get_xsave(struct kvm_vcpu *vcpu, struct kvm_xsave *guest_xsave) { - if (!vcpu->arch.guest_fpu) + if (fpstate_is_confidential(&vcpu->arch.guest_fpu)) return; - if (boot_cpu_has(X86_FEATURE_XSAVE)) { - memset(guest_xsave, 0, sizeof(struct kvm_xsave)); - fill_xsave((u8 *) guest_xsave->region, vcpu); - } else { - memcpy(guest_xsave->region, - &vcpu->arch.guest_fpu->state.fxsave, - sizeof(struct fxregs_state)); - *(u64 *)&guest_xsave->region[XSAVE_HDR_OFFSET / sizeof(u32)] = - XFEATURE_MASK_FPSSE; - } + fpu_copy_guest_fpstate_to_uabi(&vcpu->arch.guest_fpu, + guest_xsave->region, + sizeof(guest_xsave->region), + vcpu->arch.pkru); } -#define XSAVE_MXCSR_OFFSET 24 - static int kvm_vcpu_ioctl_x86_set_xsave(struct kvm_vcpu *vcpu, struct kvm_xsave *guest_xsave) { - u64 xstate_bv; - u32 mxcsr; - - if (!vcpu->arch.guest_fpu) + if (fpstate_is_confidential(&vcpu->arch.guest_fpu)) return 0; - xstate_bv = *(u64 *)&guest_xsave->region[XSAVE_HDR_OFFSET / sizeof(u32)]; - mxcsr = *(u32 *)&guest_xsave->region[XSAVE_MXCSR_OFFSET / sizeof(u32)]; - - if (boot_cpu_has(X86_FEATURE_XSAVE)) { - /* - * Here we allow setting states that are not present in - * CPUID leaf 0xD, index 0, EDX:EAX. This is for compatibility - * with old userspace. - */ - if (xstate_bv & ~supported_xcr0 || mxcsr & ~mxcsr_feature_mask) - return -EINVAL; - load_xsave(vcpu, (u8 *)guest_xsave->region); - } else { - if (xstate_bv & ~XFEATURE_MASK_FPSSE || - mxcsr & ~mxcsr_feature_mask) - return -EINVAL; - memcpy(&vcpu->arch.guest_fpu->state.fxsave, - guest_xsave->region, sizeof(struct fxregs_state)); - } - return 0; + return fpu_copy_uabi_to_guest_fpstate(&vcpu->arch.guest_fpu, + guest_xsave->region, + supported_xcr0, &vcpu->arch.pkru); } static void kvm_vcpu_ioctl_x86_get_xcrs(struct kvm_vcpu *vcpu, @@ -8434,18 +8317,11 @@ int kvm_arch_init(void *opaque) } r = -ENOMEM; - x86_fpu_cache = kmem_cache_create("x86_fpu", sizeof(struct fpu), - __alignof__(struct fpu), SLAB_ACCOUNT, - NULL); - if (!x86_fpu_cache) { - printk(KERN_ERR "kvm: failed to allocate cache for x86 fpu\n"); - goto out; - } x86_emulator_cache = kvm_alloc_emulator_cache(); if (!x86_emulator_cache) { pr_err("kvm: failed to allocate cache for x86 emulator\n"); - goto out_free_x86_fpu_cache; + goto out; } user_return_msrs = alloc_percpu(struct kvm_user_return_msrs); @@ -8483,8 +8359,6 @@ out_free_percpu: free_percpu(user_return_msrs); out_free_x86_emulator_cache: kmem_cache_destroy(x86_emulator_cache); -out_free_x86_fpu_cache: - kmem_cache_destroy(x86_fpu_cache); out: return r; } @@ -8511,7 +8385,6 @@ void kvm_arch_exit(void) kvm_mmu_module_exit(); free_percpu(user_return_msrs); kmem_cache_destroy(x86_emulator_cache); - kmem_cache_destroy(x86_fpu_cache); #ifdef CONFIG_KVM_XEN static_key_deferred_flush(&kvm_xen_enabled); WARN_ON(static_branch_unlikely(&kvm_xen_enabled.key)); @@ -9938,58 +9811,21 @@ static int complete_emulated_mmio(struct kvm_vcpu *vcpu) return 0; } -static void kvm_save_current_fpu(struct fpu *fpu) -{ - /* - * If the target FPU state is not resident in the CPU registers, just - * memcpy() from current, else save CPU state directly to the target. - */ - if (test_thread_flag(TIF_NEED_FPU_LOAD)) - memcpy(&fpu->state, ¤t->thread.fpu.state, - fpu_kernel_xstate_size); - else - save_fpregs_to_fpstate(fpu); -} - /* Swap (qemu) user FPU context for the guest FPU context. */ static void kvm_load_guest_fpu(struct kvm_vcpu *vcpu) { - fpregs_lock(); - - kvm_save_current_fpu(vcpu->arch.user_fpu); - /* - * Guests with protected state can't have it set by the hypervisor, - * so skip trying to set it. + * Exclude PKRU from restore as restored separately in + * kvm_x86_ops.run(). */ - if (vcpu->arch.guest_fpu) - /* PKRU is separately restored in kvm_x86_ops.run. */ - __restore_fpregs_from_fpstate(&vcpu->arch.guest_fpu->state, - ~XFEATURE_MASK_PKRU); - - fpregs_mark_activate(); - fpregs_unlock(); - + fpu_swap_kvm_fpstate(&vcpu->arch.guest_fpu, true); trace_kvm_fpu(1); } /* When vcpu_run ends, restore user space FPU context. */ static void kvm_put_guest_fpu(struct kvm_vcpu *vcpu) { - fpregs_lock(); - - /* - * Guests with protected state can't have it read by the hypervisor, - * so skip trying to save it. - */ - if (vcpu->arch.guest_fpu) - kvm_save_current_fpu(vcpu->arch.guest_fpu); - - restore_fpregs_from_fpstate(&vcpu->arch.user_fpu->state); - - fpregs_mark_activate(); - fpregs_unlock(); - + fpu_swap_kvm_fpstate(&vcpu->arch.guest_fpu, false); ++vcpu->stat.fpu_reload; trace_kvm_fpu(0); } @@ -10570,12 +10406,12 @@ int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu) { struct fxregs_state *fxsave; - if (!vcpu->arch.guest_fpu) + if (fpstate_is_confidential(&vcpu->arch.guest_fpu)) return 0; vcpu_load(vcpu); - fxsave = &vcpu->arch.guest_fpu->state.fxsave; + fxsave = &vcpu->arch.guest_fpu.fpstate->regs.fxsave; memcpy(fpu->fpr, fxsave->st_space, 128); fpu->fcw = fxsave->cwd; fpu->fsw = fxsave->swd; @@ -10593,12 +10429,12 @@ int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu) { struct fxregs_state *fxsave; - if (!vcpu->arch.guest_fpu) + if (fpstate_is_confidential(&vcpu->arch.guest_fpu)) return 0; vcpu_load(vcpu); - fxsave = &vcpu->arch.guest_fpu->state.fxsave; + fxsave = &vcpu->arch.guest_fpu.fpstate->regs.fxsave; memcpy(fxsave->st_space, fpu->fpr, 128); fxsave->cwd = fpu->fcw; @@ -10651,14 +10487,6 @@ static int sync_regs(struct kvm_vcpu *vcpu) static void fx_init(struct kvm_vcpu *vcpu) { - if (!vcpu->arch.guest_fpu) - return; - - fpstate_init(&vcpu->arch.guest_fpu->state); - if (boot_cpu_has(X86_FEATURE_XSAVES)) - vcpu->arch.guest_fpu->state.xsave.header.xcomp_bv = - host_xcr0 | XSTATE_COMPACTION_ENABLED; - /* * Ensure guest xcr0 is valid for loading */ @@ -10667,15 +10495,6 @@ static void fx_init(struct kvm_vcpu *vcpu) vcpu->arch.cr0 |= X86_CR0_ET; } -void kvm_free_guest_fpu(struct kvm_vcpu *vcpu) -{ - if (vcpu->arch.guest_fpu) { - kmem_cache_free(x86_fpu_cache, vcpu->arch.guest_fpu); - vcpu->arch.guest_fpu = NULL; - } -} -EXPORT_SYMBOL_GPL(kvm_free_guest_fpu); - int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id) { if (kvm_check_tsc_unstable() && atomic_read(&kvm->online_vcpus) != 0) @@ -10732,19 +10551,11 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) if (!alloc_emulate_ctxt(vcpu)) goto free_wbinvd_dirty_mask; - vcpu->arch.user_fpu = kmem_cache_zalloc(x86_fpu_cache, - GFP_KERNEL_ACCOUNT); - if (!vcpu->arch.user_fpu) { - pr_err("kvm: failed to allocate userspace's fpu\n"); + if (!fpu_alloc_guest_fpstate(&vcpu->arch.guest_fpu)) { + pr_err("kvm: failed to allocate vcpu's fpu\n"); goto free_emulate_ctxt; } - vcpu->arch.guest_fpu = kmem_cache_zalloc(x86_fpu_cache, - GFP_KERNEL_ACCOUNT); - if (!vcpu->arch.guest_fpu) { - pr_err("kvm: failed to allocate vcpu's fpu\n"); - goto free_user_fpu; - } fx_init(vcpu); vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu); @@ -10777,9 +10588,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) return 0; free_guest_fpu: - kvm_free_guest_fpu(vcpu); -free_user_fpu: - kmem_cache_free(x86_fpu_cache, vcpu->arch.user_fpu); + fpu_free_guest_fpstate(&vcpu->arch.guest_fpu); free_emulate_ctxt: kmem_cache_free(x86_emulator_cache, vcpu->arch.emulate_ctxt); free_wbinvd_dirty_mask: @@ -10828,8 +10637,7 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) kmem_cache_free(x86_emulator_cache, vcpu->arch.emulate_ctxt); free_cpumask_var(vcpu->arch.wbinvd_dirty_mask); - kmem_cache_free(x86_fpu_cache, vcpu->arch.user_fpu); - kvm_free_guest_fpu(vcpu); + fpu_free_guest_fpstate(&vcpu->arch.guest_fpu); kvm_hv_vcpu_uninit(vcpu); kvm_pmu_destroy(vcpu); @@ -10881,8 +10689,8 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) kvm_async_pf_hash_reset(vcpu); vcpu->arch.apf.halted = false; - if (vcpu->arch.guest_fpu && kvm_mpx_supported()) { - void *mpx_state_buffer; + if (vcpu->arch.guest_fpu.fpstate && kvm_mpx_supported()) { + struct fpstate *fpstate = vcpu->arch.guest_fpu.fpstate; /* * To avoid have the INIT path from kvm_apic_has_events() that be @@ -10890,14 +10698,10 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) */ if (init_event) kvm_put_guest_fpu(vcpu); - mpx_state_buffer = get_xsave_addr(&vcpu->arch.guest_fpu->state.xsave, - XFEATURE_BNDREGS); - if (mpx_state_buffer) - memset(mpx_state_buffer, 0, sizeof(struct mpx_bndreg_state)); - mpx_state_buffer = get_xsave_addr(&vcpu->arch.guest_fpu->state.xsave, - XFEATURE_BNDCSR); - if (mpx_state_buffer) - memset(mpx_state_buffer, 0, sizeof(struct mpx_bndcsr)); + + fpstate_clear_xstate_component(fpstate, XFEATURE_BNDREGS); + fpstate_clear_xstate_component(fpstate, XFEATURE_BNDCSR); + if (init_event) kvm_load_guest_fpu(vcpu); } diff --git a/arch/x86/lib/copy_mc_64.S b/arch/x86/lib/copy_mc_64.S index e5f77e2..7334055 100644 --- a/arch/x86/lib/copy_mc_64.S +++ b/arch/x86/lib/copy_mc_64.S @@ -107,9 +107,9 @@ SYM_FUNC_END(copy_mc_fragile) .previous - _ASM_EXTABLE_FAULT(.L_read_leading_bytes, .E_leading_bytes) - _ASM_EXTABLE_FAULT(.L_read_words, .E_read_words) - _ASM_EXTABLE_FAULT(.L_read_trailing_bytes, .E_trailing_bytes) + _ASM_EXTABLE_TYPE(.L_read_leading_bytes, .E_leading_bytes, EX_TYPE_DEFAULT_MCE_SAFE) + _ASM_EXTABLE_TYPE(.L_read_words, .E_read_words, EX_TYPE_DEFAULT_MCE_SAFE) + _ASM_EXTABLE_TYPE(.L_read_trailing_bytes, .E_trailing_bytes, EX_TYPE_DEFAULT_MCE_SAFE) _ASM_EXTABLE(.L_write_leading_bytes, .E_leading_bytes) _ASM_EXTABLE(.L_write_words, .E_write_words) _ASM_EXTABLE(.L_write_trailing_bytes, .E_trailing_bytes) @@ -149,5 +149,5 @@ SYM_FUNC_END(copy_mc_enhanced_fast_string) .previous - _ASM_EXTABLE_FAULT(.L_copy, .E_copy) + _ASM_EXTABLE_TYPE(.L_copy, .E_copy, EX_TYPE_DEFAULT_MCE_SAFE) #endif /* !CONFIG_UML */ diff --git a/arch/x86/math-emu/fpu_aux.c b/arch/x86/math-emu/fpu_aux.c index 0347484..d62662b 100644 --- a/arch/x86/math-emu/fpu_aux.c +++ b/arch/x86/math-emu/fpu_aux.c @@ -53,7 +53,7 @@ void fpstate_init_soft(struct swregs_state *soft) void finit(void) { - fpstate_init_soft(¤t->thread.fpu.state.soft); + fpstate_init_soft(¤t->thread.fpu.fpstate->regs.soft); } /* diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c index 8679a9d..7fe56c5 100644 --- a/arch/x86/math-emu/fpu_entry.c +++ b/arch/x86/math-emu/fpu_entry.c @@ -31,7 +31,7 @@ #include #include #include -#include +#include #include "fpu_system.h" #include "fpu_emu.h" @@ -640,7 +640,7 @@ int fpregs_soft_set(struct task_struct *target, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { - struct swregs_state *s387 = &target->thread.fpu.state.soft; + struct swregs_state *s387 = &target->thread.fpu.fpstate->regs.soft; void *space = s387->st_space; int ret; int offset, other, i, tags, regnr, tag, newtop; @@ -691,7 +691,7 @@ int fpregs_soft_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { - struct swregs_state *s387 = &target->thread.fpu.state.soft; + struct swregs_state *s387 = &target->thread.fpu.fpstate->regs.soft; const void *space = s387->st_space; int offset = (S387->ftop & 7) * 10, other = 80 - offset; diff --git a/arch/x86/math-emu/fpu_system.h b/arch/x86/math-emu/fpu_system.h index 9b41391..eec3e48 100644 --- a/arch/x86/math-emu/fpu_system.h +++ b/arch/x86/math-emu/fpu_system.h @@ -73,7 +73,7 @@ static inline bool seg_writable(struct desc_struct *d) return (d->type & SEG_TYPE_EXECUTE_MASK) == SEG_TYPE_WRITABLE; } -#define I387 (¤t->thread.fpu.state) +#define I387 (¤t->thread.fpu.fpstate->regs) #define FPU_info (I387->soft.info) #define FPU_CS (*(unsigned short *) &(FPU_info->regs->cs)) diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index e1664e9..5cd2a88 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -4,46 +4,30 @@ #include #include -#include +#include #include #include #include -typedef bool (*ex_handler_t)(const struct exception_table_entry *, - struct pt_regs *, int, unsigned long, - unsigned long); - static inline unsigned long ex_fixup_addr(const struct exception_table_entry *x) { return (unsigned long)&x->fixup + x->fixup; } -static inline ex_handler_t -ex_fixup_handler(const struct exception_table_entry *x) -{ - return (ex_handler_t)((unsigned long)&x->handler + x->handler); -} -__visible bool ex_handler_default(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr, - unsigned long error_code, - unsigned long fault_addr) +static bool ex_handler_default(const struct exception_table_entry *fixup, + struct pt_regs *regs) { regs->ip = ex_fixup_addr(fixup); return true; } -EXPORT_SYMBOL(ex_handler_default); -__visible bool ex_handler_fault(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr, - unsigned long error_code, - unsigned long fault_addr) +static bool ex_handler_fault(const struct exception_table_entry *fixup, + struct pt_regs *regs, int trapnr) { - regs->ip = ex_fixup_addr(fixup); regs->ax = trapnr; - return true; + return ex_handler_default(fixup, regs); } -EXPORT_SYMBOL_GPL(ex_handler_fault); /* * Handler for when we fail to restore a task's FPU state. We should never get @@ -55,65 +39,47 @@ EXPORT_SYMBOL_GPL(ex_handler_fault); * of vulnerability by restoring from the initial state (essentially, zeroing * out all the FPU registers) if we can't restore from the task's FPU state. */ -__visible bool ex_handler_fprestore(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr, - unsigned long error_code, - unsigned long fault_addr) +static bool ex_handler_fprestore(const struct exception_table_entry *fixup, + struct pt_regs *regs) { regs->ip = ex_fixup_addr(fixup); WARN_ONCE(1, "Bad FPU state detected at %pB, reinitializing FPU registers.", (void *)instruction_pointer(regs)); - __restore_fpregs_from_fpstate(&init_fpstate, xfeatures_mask_fpstate()); + fpu_reset_from_exception_fixup(); return true; } -EXPORT_SYMBOL_GPL(ex_handler_fprestore); -__visible bool ex_handler_uaccess(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr, - unsigned long error_code, - unsigned long fault_addr) +static bool ex_handler_uaccess(const struct exception_table_entry *fixup, + struct pt_regs *regs, int trapnr) { WARN_ONCE(trapnr == X86_TRAP_GP, "General protection fault in user access. Non-canonical address?"); - regs->ip = ex_fixup_addr(fixup); - return true; + return ex_handler_default(fixup, regs); } -EXPORT_SYMBOL(ex_handler_uaccess); -__visible bool ex_handler_copy(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr, - unsigned long error_code, - unsigned long fault_addr) +static bool ex_handler_copy(const struct exception_table_entry *fixup, + struct pt_regs *regs, int trapnr) { WARN_ONCE(trapnr == X86_TRAP_GP, "General protection fault in user access. Non-canonical address?"); - regs->ip = ex_fixup_addr(fixup); - regs->ax = trapnr; - return true; + return ex_handler_fault(fixup, regs, trapnr); } -EXPORT_SYMBOL(ex_handler_copy); -__visible bool ex_handler_rdmsr_unsafe(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr, - unsigned long error_code, - unsigned long fault_addr) +static bool ex_handler_rdmsr_unsafe(const struct exception_table_entry *fixup, + struct pt_regs *regs) { if (pr_warn_once("unchecked MSR access error: RDMSR from 0x%x at rIP: 0x%lx (%pS)\n", (unsigned int)regs->cx, regs->ip, (void *)regs->ip)) show_stack_regs(regs); /* Pretend that the read succeeded and returned 0. */ - regs->ip = ex_fixup_addr(fixup); regs->ax = 0; regs->dx = 0; - return true; + return ex_handler_default(fixup, regs); } -EXPORT_SYMBOL(ex_handler_rdmsr_unsafe); -__visible bool ex_handler_wrmsr_unsafe(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr, - unsigned long error_code, - unsigned long fault_addr) +static bool ex_handler_wrmsr_unsafe(const struct exception_table_entry *fixup, + struct pt_regs *regs) { if (pr_warn_once("unchecked MSR access error: WRMSR to 0x%x (tried to write 0x%08x%08x) at rIP: 0x%lx (%pS)\n", (unsigned int)regs->cx, (unsigned int)regs->dx, @@ -121,45 +87,29 @@ __visible bool ex_handler_wrmsr_unsafe(const struct exception_table_entry *fixup show_stack_regs(regs); /* Pretend that the write succeeded. */ - regs->ip = ex_fixup_addr(fixup); - return true; + return ex_handler_default(fixup, regs); } -EXPORT_SYMBOL(ex_handler_wrmsr_unsafe); -__visible bool ex_handler_clear_fs(const struct exception_table_entry *fixup, - struct pt_regs *regs, int trapnr, - unsigned long error_code, - unsigned long fault_addr) +static bool ex_handler_clear_fs(const struct exception_table_entry *fixup, + struct pt_regs *regs) { if (static_cpu_has(X86_BUG_NULL_SEG)) asm volatile ("mov %0, %%fs" : : "rm" (__USER_DS)); asm volatile ("mov %0, %%fs" : : "rm" (0)); - return ex_handler_default(fixup, regs, trapnr, error_code, fault_addr); + return ex_handler_default(fixup, regs); } -EXPORT_SYMBOL(ex_handler_clear_fs); -enum handler_type ex_get_fault_handler_type(unsigned long ip) +int ex_get_fixup_type(unsigned long ip) { - const struct exception_table_entry *e; - ex_handler_t handler; + const struct exception_table_entry *e = search_exception_tables(ip); - e = search_exception_tables(ip); - if (!e) - return EX_HANDLER_NONE; - handler = ex_fixup_handler(e); - if (handler == ex_handler_fault) - return EX_HANDLER_FAULT; - else if (handler == ex_handler_uaccess || handler == ex_handler_copy) - return EX_HANDLER_UACCESS; - else - return EX_HANDLER_OTHER; + return e ? e->type : EX_TYPE_NONE; } int fixup_exception(struct pt_regs *regs, int trapnr, unsigned long error_code, unsigned long fault_addr) { const struct exception_table_entry *e; - ex_handler_t handler; #ifdef CONFIG_PNPBIOS if (unlikely(SEGMENT_IS_PNP_CODE(regs->cs))) { @@ -179,8 +129,35 @@ int fixup_exception(struct pt_regs *regs, int trapnr, unsigned long error_code, if (!e) return 0; - handler = ex_fixup_handler(e); - return handler(e, regs, trapnr, error_code, fault_addr); + switch (e->type) { + case EX_TYPE_DEFAULT: + case EX_TYPE_DEFAULT_MCE_SAFE: + return ex_handler_default(e, regs); + case EX_TYPE_FAULT: + case EX_TYPE_FAULT_MCE_SAFE: + return ex_handler_fault(e, regs, trapnr); + case EX_TYPE_UACCESS: + return ex_handler_uaccess(e, regs, trapnr); + case EX_TYPE_COPY: + return ex_handler_copy(e, regs, trapnr); + case EX_TYPE_CLEAR_FS: + return ex_handler_clear_fs(e, regs); + case EX_TYPE_FPU_RESTORE: + return ex_handler_fprestore(e, regs); + case EX_TYPE_RDMSR: + return ex_handler_rdmsr_unsafe(e, regs); + case EX_TYPE_WRMSR: + return ex_handler_wrmsr_unsafe(e, regs); + case EX_TYPE_BPF: + return ex_handler_bpf(e, regs); + case EX_TYPE_RDMSR_IN_MCE: + ex_handler_msr_mce(regs, false); + break; + case EX_TYPE_WRMSR_IN_MCE: + ex_handler_msr_mce(regs, true); + break; + } + BUG(); } extern unsigned int early_recursion_flag; diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 39c8025..8796559 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -803,9 +803,7 @@ static int emit_atomic(u8 **pprog, u8 atomic_op, return 0; } -static bool ex_handler_bpf(const struct exception_table_entry *x, - struct pt_regs *regs, int trapnr, - unsigned long error_code, unsigned long fault_addr) +bool ex_handler_bpf(const struct exception_table_entry *x, struct pt_regs *regs) { u32 reg = x->fixup >> 8; @@ -1288,12 +1286,7 @@ st: if (is_imm8(insn->off)) } ex->insn = delta; - delta = (u8 *)ex_handler_bpf - (u8 *)&ex->handler; - if (!is_simm32(delta)) { - pr_err("extable->handler doesn't fit into 32-bit\n"); - return -EFAULT; - } - ex->handler = delta; + ex->type = EX_TYPE_BPF; if (dst_reg > BPF_REG_9) { pr_err("verifier error\n"); diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c index 6665f88..9f2b251 100644 --- a/arch/x86/power/cpu.c +++ b/arch/x86/power/cpu.c @@ -20,7 +20,7 @@ #include #include #include -#include +#include #include #include #include diff --git a/include/linux/signal.h b/include/linux/signal.h index 3f96a63..7d34105 100644 --- a/include/linux/signal.h +++ b/include/linux/signal.h @@ -464,6 +464,12 @@ int __save_altstack(stack_t __user *, unsigned long); unsafe_put_user(t->sas_ss_size, &__uss->ss_size, label); \ } while (0); +#ifdef CONFIG_DYNAMIC_SIGFRAME +bool sigaltstack_size_valid(size_t ss_size); +#else +static inline bool sigaltstack_size_valid(size_t size) { return true; } +#endif /* !CONFIG_DYNAMIC_SIGFRAME */ + #ifdef CONFIG_PROC_FS struct seq_file; extern void render_sigset_t(struct seq_file *, const char *, sigset_t *); diff --git a/kernel/signal.c b/kernel/signal.c index 487bf4f..e99aff3 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -4138,11 +4138,29 @@ int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) return 0; } +#ifdef CONFIG_DYNAMIC_SIGFRAME +static inline void sigaltstack_lock(void) + __acquires(¤t->sighand->siglock) +{ + spin_lock_irq(¤t->sighand->siglock); +} + +static inline void sigaltstack_unlock(void) + __releases(¤t->sighand->siglock) +{ + spin_unlock_irq(¤t->sighand->siglock); +} +#else +static inline void sigaltstack_lock(void) { } +static inline void sigaltstack_unlock(void) { } +#endif + static int do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp, size_t min_ss_size) { struct task_struct *t = current; + int ret = 0; if (oss) { memset(oss, 0, sizeof(stack_t)); @@ -4166,19 +4184,24 @@ do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp, ss_mode != 0)) return -EINVAL; + sigaltstack_lock(); if (ss_mode == SS_DISABLE) { ss_size = 0; ss_sp = NULL; } else { if (unlikely(ss_size < min_ss_size)) - return -ENOMEM; + ret = -ENOMEM; + if (!sigaltstack_size_valid(ss_size)) + ret = -ENOMEM; } - - t->sas_ss_sp = (unsigned long) ss_sp; - t->sas_ss_size = ss_size; - t->sas_ss_flags = ss_flags; + if (!ret) { + t->sas_ss_sp = (unsigned long) ss_sp; + t->sas_ss_size = ss_size; + t->sas_ss_flags = ss_flags; + } + sigaltstack_unlock(); } - return 0; + return ret; } SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss) diff --git a/scripts/sorttable.c b/scripts/sorttable.c index 6ee4fa8..278bb53 100644 --- a/scripts/sorttable.c +++ b/scripts/sorttable.c @@ -240,7 +240,7 @@ static void x86_sort_relative_table(char *extab_image, int image_size) w(r(loc) + i, loc); w(r(loc + 1) + i + 4, loc + 1); - w(r(loc + 2) + i + 8, loc + 2); + /* Don't touch the fixup type */ i += sizeof(uint32_t) * 3; } @@ -253,7 +253,7 @@ static void x86_sort_relative_table(char *extab_image, int image_size) w(r(loc) - i, loc); w(r(loc + 1) - (i + 4), loc + 1); - w(r(loc + 2) - (i + 8), loc + 2); + /* Don't touch the fixup type */ i += sizeof(uint32_t) * 3; } diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile index b4142cd..8a1f62a 100644 --- a/tools/testing/selftests/x86/Makefile +++ b/tools/testing/selftests/x86/Makefile @@ -18,7 +18,7 @@ TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \ test_FCMOV test_FCOMI test_FISTTP \ vdso_restorer TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip syscall_numbering \ - corrupt_xstate_header + corrupt_xstate_header amx # Some selftests require 32bit support enabled also on 64bit systems TARGETS_C_32BIT_NEEDED := ldt_gdt ptrace_syscall diff --git a/tools/testing/selftests/x86/amx.c b/tools/testing/selftests/x86/amx.c new file mode 100644 index 0000000..3615ef4 --- /dev/null +++ b/tools/testing/selftests/x86/amx.c @@ -0,0 +1,851 @@ +// SPDX-License-Identifier: GPL-2.0 + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +#ifndef __x86_64__ +# error This test is 64-bit only +#endif + +#define XSAVE_HDR_OFFSET 512 +#define XSAVE_HDR_SIZE 64 + +struct xsave_buffer { + union { + struct { + char legacy[XSAVE_HDR_OFFSET]; + char header[XSAVE_HDR_SIZE]; + char extended[0]; + }; + char bytes[0]; + }; +}; + +static inline uint64_t xgetbv(uint32_t index) +{ + uint32_t eax, edx; + + asm volatile("xgetbv;" + : "=a" (eax), "=d" (edx) + : "c" (index)); + return eax + ((uint64_t)edx << 32); +} + +static inline void cpuid(uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx) +{ + asm volatile("cpuid;" + : "=a" (*eax), "=b" (*ebx), "=c" (*ecx), "=d" (*edx) + : "0" (*eax), "2" (*ecx)); +} + +static inline void xsave(struct xsave_buffer *xbuf, uint64_t rfbm) +{ + uint32_t rfbm_lo = rfbm; + uint32_t rfbm_hi = rfbm >> 32; + + asm volatile("xsave (%%rdi)" + : : "D" (xbuf), "a" (rfbm_lo), "d" (rfbm_hi) + : "memory"); +} + +static inline void xrstor(struct xsave_buffer *xbuf, uint64_t rfbm) +{ + uint32_t rfbm_lo = rfbm; + uint32_t rfbm_hi = rfbm >> 32; + + asm volatile("xrstor (%%rdi)" + : : "D" (xbuf), "a" (rfbm_lo), "d" (rfbm_hi)); +} + +/* err() exits and will not return */ +#define fatal_error(msg, ...) err(1, "[FAIL]\t" msg, ##__VA_ARGS__) + +static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), + int flags) +{ + struct sigaction sa; + + memset(&sa, 0, sizeof(sa)); + sa.sa_sigaction = handler; + sa.sa_flags = SA_SIGINFO | flags; + sigemptyset(&sa.sa_mask); + if (sigaction(sig, &sa, 0)) + fatal_error("sigaction"); +} + +static void clearhandler(int sig) +{ + struct sigaction sa; + + memset(&sa, 0, sizeof(sa)); + sa.sa_handler = SIG_DFL; + sigemptyset(&sa.sa_mask); + if (sigaction(sig, &sa, 0)) + fatal_error("sigaction"); +} + +#define XFEATURE_XTILECFG 17 +#define XFEATURE_XTILEDATA 18 +#define XFEATURE_MASK_XTILECFG (1 << XFEATURE_XTILECFG) +#define XFEATURE_MASK_XTILEDATA (1 << XFEATURE_XTILEDATA) +#define XFEATURE_MASK_XTILE (XFEATURE_MASK_XTILECFG | XFEATURE_MASK_XTILEDATA) + +#define CPUID_LEAF1_ECX_XSAVE_MASK (1 << 26) +#define CPUID_LEAF1_ECX_OSXSAVE_MASK (1 << 27) +static inline void check_cpuid_xsave(void) +{ + uint32_t eax, ebx, ecx, edx; + + /* + * CPUID.1:ECX.XSAVE[bit 26] enumerates general + * support for the XSAVE feature set, including + * XGETBV. + */ + eax = 1; + ecx = 0; + cpuid(&eax, &ebx, &ecx, &edx); + if (!(ecx & CPUID_LEAF1_ECX_XSAVE_MASK)) + fatal_error("cpuid: no CPU xsave support"); + if (!(ecx & CPUID_LEAF1_ECX_OSXSAVE_MASK)) + fatal_error("cpuid: no OS xsave support"); +} + +static uint32_t xbuf_size; + +static struct { + uint32_t xbuf_offset; + uint32_t size; +} xtiledata; + +#define CPUID_LEAF_XSTATE 0xd +#define CPUID_SUBLEAF_XSTATE_USER 0x0 +#define TILE_CPUID 0x1d +#define TILE_PALETTE_ID 0x1 + +static void check_cpuid_xtiledata(void) +{ + uint32_t eax, ebx, ecx, edx; + + eax = CPUID_LEAF_XSTATE; + ecx = CPUID_SUBLEAF_XSTATE_USER; + cpuid(&eax, &ebx, &ecx, &edx); + + /* + * EBX enumerates the size (in bytes) required by the XSAVE + * instruction for an XSAVE area containing all the user state + * components corresponding to bits currently set in XCR0. + * + * Stash that off so it can be used to allocate buffers later. + */ + xbuf_size = ebx; + + eax = CPUID_LEAF_XSTATE; + ecx = XFEATURE_XTILEDATA; + + cpuid(&eax, &ebx, &ecx, &edx); + /* + * eax: XTILEDATA state component size + * ebx: XTILEDATA state component offset in user buffer + */ + if (!eax || !ebx) + fatal_error("xstate cpuid: invalid tile data size/offset: %d/%d", + eax, ebx); + + xtiledata.size = eax; + xtiledata.xbuf_offset = ebx; +} + +/* The helpers for managing XSAVE buffer and tile states: */ + +struct xsave_buffer *alloc_xbuf(void) +{ + struct xsave_buffer *xbuf; + + /* XSAVE buffer should be 64B-aligned. */ + xbuf = aligned_alloc(64, xbuf_size); + if (!xbuf) + fatal_error("aligned_alloc()"); + return xbuf; +} + +static inline void clear_xstate_header(struct xsave_buffer *buffer) +{ + memset(&buffer->header, 0, sizeof(buffer->header)); +} + +static inline uint64_t get_xstatebv(struct xsave_buffer *buffer) +{ + /* XSTATE_BV is at the beginning of the header: */ + return *(uint64_t *)&buffer->header; +} + +static inline void set_xstatebv(struct xsave_buffer *buffer, uint64_t bv) +{ + /* XSTATE_BV is at the beginning of the header: */ + *(uint64_t *)(&buffer->header) = bv; +} + +static void set_rand_tiledata(struct xsave_buffer *xbuf) +{ + int *ptr = (int *)&xbuf->bytes[xtiledata.xbuf_offset]; + int data; + int i; + + /* + * Ensure that 'data' is never 0. This ensures that + * the registers are never in their initial configuration + * and thus never tracked as being in the init state. + */ + data = rand() | 1; + + for (i = 0; i < xtiledata.size / sizeof(int); i++, ptr++) + *ptr = data; +} + +struct xsave_buffer *stashed_xsave; + +static void init_stashed_xsave(void) +{ + stashed_xsave = alloc_xbuf(); + if (!stashed_xsave) + fatal_error("failed to allocate stashed_xsave\n"); + clear_xstate_header(stashed_xsave); +} + +static void free_stashed_xsave(void) +{ + free(stashed_xsave); +} + +/* See 'struct _fpx_sw_bytes' at sigcontext.h */ +#define SW_BYTES_OFFSET 464 +/* N.B. The struct's field name varies so read from the offset. */ +#define SW_BYTES_BV_OFFSET (SW_BYTES_OFFSET + 8) + +static inline struct _fpx_sw_bytes *get_fpx_sw_bytes(void *buffer) +{ + return (struct _fpx_sw_bytes *)(buffer + SW_BYTES_OFFSET); +} + +static inline uint64_t get_fpx_sw_bytes_features(void *buffer) +{ + return *(uint64_t *)(buffer + SW_BYTES_BV_OFFSET); +} + +/* Work around printf() being unsafe in signals: */ +#define SIGNAL_BUF_LEN 1000 +char signal_message_buffer[SIGNAL_BUF_LEN]; +void sig_print(char *msg) +{ + int left = SIGNAL_BUF_LEN - strlen(signal_message_buffer) - 1; + + strncat(signal_message_buffer, msg, left); +} + +static volatile bool noperm_signaled; +static int noperm_errs; +/* + * Signal handler for when AMX is used but + * permission has not been obtained. + */ +static void handle_noperm(int sig, siginfo_t *si, void *ctx_void) +{ + ucontext_t *ctx = (ucontext_t *)ctx_void; + void *xbuf = ctx->uc_mcontext.fpregs; + struct _fpx_sw_bytes *sw_bytes; + uint64_t features; + + /* Reset the signal message buffer: */ + signal_message_buffer[0] = '\0'; + sig_print("\tAt SIGILL handler,\n"); + + if (si->si_code != ILL_ILLOPC) { + noperm_errs++; + sig_print("[FAIL]\tInvalid signal code.\n"); + } else { + sig_print("[OK]\tValid signal code (ILL_ILLOPC).\n"); + } + + sw_bytes = get_fpx_sw_bytes(xbuf); + /* + * Without permission, the signal XSAVE buffer should not + * have room for AMX register state (aka. xtiledata). + * Check that the size does not overlap with where xtiledata + * will reside. + * + * This also implies that no state components *PAST* + * XTILEDATA (features >=19) can be present in the buffer. + */ + if (sw_bytes->xstate_size <= xtiledata.xbuf_offset) { + sig_print("[OK]\tValid xstate size\n"); + } else { + noperm_errs++; + sig_print("[FAIL]\tInvalid xstate size\n"); + } + + features = get_fpx_sw_bytes_features(xbuf); + /* + * Without permission, the XTILEDATA feature + * bit should not be set. + */ + if ((features & XFEATURE_MASK_XTILEDATA) == 0) { + sig_print("[OK]\tValid xstate mask\n"); + } else { + noperm_errs++; + sig_print("[FAIL]\tInvalid xstate mask\n"); + } + + noperm_signaled = true; + ctx->uc_mcontext.gregs[REG_RIP] += 3; /* Skip the faulting XRSTOR */ +} + +/* Return true if XRSTOR is successful; otherwise, false. */ +static inline bool xrstor_safe(struct xsave_buffer *xbuf, uint64_t mask) +{ + noperm_signaled = false; + xrstor(xbuf, mask); + + /* Print any messages produced by the signal code: */ + printf("%s", signal_message_buffer); + /* + * Reset the buffer to make sure any future printing + * only outputs new messages: + */ + signal_message_buffer[0] = '\0'; + + if (noperm_errs) + fatal_error("saw %d errors in noperm signal handler\n", noperm_errs); + + return !noperm_signaled; +} + +/* + * Use XRSTOR to populate the XTILEDATA registers with + * random data. + * + * Return true if successful; otherwise, false. + */ +static inline bool load_rand_tiledata(struct xsave_buffer *xbuf) +{ + clear_xstate_header(xbuf); + set_xstatebv(xbuf, XFEATURE_MASK_XTILEDATA); + set_rand_tiledata(xbuf); + return xrstor_safe(xbuf, XFEATURE_MASK_XTILEDATA); +} + +/* Return XTILEDATA to its initial configuration. */ +static inline void init_xtiledata(void) +{ + clear_xstate_header(stashed_xsave); + xrstor_safe(stashed_xsave, XFEATURE_MASK_XTILEDATA); +} + +enum expected_result { FAIL_EXPECTED, SUCCESS_EXPECTED }; + +/* arch_prctl() and sigaltstack() test */ + +#define ARCH_GET_XCOMP_PERM 0x1022 +#define ARCH_REQ_XCOMP_PERM 0x1023 + +static void req_xtiledata_perm(void) +{ + syscall(SYS_arch_prctl, ARCH_REQ_XCOMP_PERM, XFEATURE_XTILEDATA); +} + +static void validate_req_xcomp_perm(enum expected_result exp) +{ + unsigned long bitmask; + long rc; + + rc = syscall(SYS_arch_prctl, ARCH_REQ_XCOMP_PERM, XFEATURE_XTILEDATA); + if (exp == FAIL_EXPECTED) { + if (rc) { + printf("[OK]\tARCH_REQ_XCOMP_PERM saw expected failure..\n"); + return; + } + + fatal_error("ARCH_REQ_XCOMP_PERM saw unexpected success.\n"); + } else if (rc) { + fatal_error("ARCH_REQ_XCOMP_PERM saw unexpected failure.\n"); + } + + rc = syscall(SYS_arch_prctl, ARCH_GET_XCOMP_PERM, &bitmask); + if (rc) { + fatal_error("prctl(ARCH_GET_XCOMP_PERM) error: %ld", rc); + } else if (bitmask & XFEATURE_MASK_XTILE) { + printf("\tARCH_REQ_XCOMP_PERM is successful.\n"); + } +} + +static void validate_xcomp_perm(enum expected_result exp) +{ + bool load_success = load_rand_tiledata(stashed_xsave); + + if (exp == FAIL_EXPECTED) { + if (load_success) { + noperm_errs++; + printf("[FAIL]\tLoad tiledata succeeded.\n"); + } else { + printf("[OK]\tLoad tiledata failed.\n"); + } + } else if (exp == SUCCESS_EXPECTED) { + if (load_success) { + printf("[OK]\tLoad tiledata succeeded.\n"); + } else { + noperm_errs++; + printf("[FAIL]\tLoad tiledata failed.\n"); + } + } +} + +#ifndef AT_MINSIGSTKSZ +# define AT_MINSIGSTKSZ 51 +#endif + +static void *alloc_altstack(unsigned int size) +{ + void *altstack; + + altstack = mmap(NULL, size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0); + + if (altstack == MAP_FAILED) + fatal_error("mmap() for altstack"); + + return altstack; +} + +static void setup_altstack(void *addr, unsigned long size, enum expected_result exp) +{ + stack_t ss; + int rc; + + memset(&ss, 0, sizeof(ss)); + ss.ss_size = size; + ss.ss_sp = addr; + + rc = sigaltstack(&ss, NULL); + + if (exp == FAIL_EXPECTED) { + if (rc) { + printf("[OK]\tsigaltstack() failed.\n"); + } else { + fatal_error("sigaltstack() succeeded unexpectedly.\n"); + } + } else if (rc) { + fatal_error("sigaltstack()"); + } +} + +static void test_dynamic_sigaltstack(void) +{ + unsigned int small_size, enough_size; + unsigned long minsigstksz; + void *altstack; + + minsigstksz = getauxval(AT_MINSIGSTKSZ); + printf("\tAT_MINSIGSTKSZ = %lu\n", minsigstksz); + /* + * getauxval() itself can return 0 for failure or + * success. But, in this case, AT_MINSIGSTKSZ + * will always return a >=0 value if implemented. + * Just check for 0. + */ + if (minsigstksz == 0) { + printf("no support for AT_MINSIGSTKSZ, skipping sigaltstack tests\n"); + return; + } + + enough_size = minsigstksz * 2; + + altstack = alloc_altstack(enough_size); + printf("\tAllocate memory for altstack (%u bytes).\n", enough_size); + + /* + * Try setup_altstack() with a size which can not fit + * XTILEDATA. ARCH_REQ_XCOMP_PERM should fail. + */ + small_size = minsigstksz - xtiledata.size; + printf("\tAfter sigaltstack() with small size (%u bytes).\n", small_size); + setup_altstack(altstack, small_size, SUCCESS_EXPECTED); + validate_req_xcomp_perm(FAIL_EXPECTED); + + /* + * Try setup_altstack() with a size derived from + * AT_MINSIGSTKSZ. It should be more than large enough + * and thus ARCH_REQ_XCOMP_PERM should succeed. + */ + printf("\tAfter sigaltstack() with enough size (%u bytes).\n", enough_size); + setup_altstack(altstack, enough_size, SUCCESS_EXPECTED); + validate_req_xcomp_perm(SUCCESS_EXPECTED); + + /* + * Try to coerce setup_altstack() to again accept a + * too-small altstack. This ensures that big-enough + * sigaltstacks can not shrink to a too-small value + * once XTILEDATA permission is established. + */ + printf("\tThen, sigaltstack() with small size (%u bytes).\n", small_size); + setup_altstack(altstack, small_size, FAIL_EXPECTED); +} + +static void test_dynamic_state(void) +{ + pid_t parent, child, grandchild; + + parent = fork(); + if (parent < 0) { + /* fork() failed */ + fatal_error("fork"); + } else if (parent > 0) { + int status; + /* fork() succeeded. Now in the parent. */ + + wait(&status); + if (!WIFEXITED(status) || WEXITSTATUS(status)) + fatal_error("arch_prctl test parent exit"); + return; + } + /* fork() succeeded. Now in the child . */ + + printf("[RUN]\tCheck ARCH_REQ_XCOMP_PERM around process fork() and sigaltack() test.\n"); + + printf("\tFork a child.\n"); + child = fork(); + if (child < 0) { + fatal_error("fork"); + } else if (child > 0) { + int status; + + wait(&status); + if (!WIFEXITED(status) || WEXITSTATUS(status)) + fatal_error("arch_prctl test child exit"); + _exit(0); + } + + /* + * The permission request should fail without an + * XTILEDATA-compatible signal stack + */ + printf("\tTest XCOMP_PERM at child.\n"); + validate_xcomp_perm(FAIL_EXPECTED); + + /* + * Set up an XTILEDATA-compatible signal stack and + * also obtain permission to populate XTILEDATA. + */ + printf("\tTest dynamic sigaltstack at child:\n"); + test_dynamic_sigaltstack(); + + /* Ensure that XTILEDATA can be populated. */ + printf("\tTest XCOMP_PERM again at child.\n"); + validate_xcomp_perm(SUCCESS_EXPECTED); + + printf("\tFork a grandchild.\n"); + grandchild = fork(); + if (grandchild < 0) { + /* fork() failed */ + fatal_error("fork"); + } else if (!grandchild) { + /* fork() succeeded. Now in the (grand)child. */ + printf("\tTest XCOMP_PERM at grandchild.\n"); + + /* + * Ensure that the grandchild inherited + * permission and a compatible sigaltstack: + */ + validate_xcomp_perm(SUCCESS_EXPECTED); + } else { + int status; + /* fork() succeeded. Now in the parent. */ + + wait(&status); + if (!WIFEXITED(status) || WEXITSTATUS(status)) + fatal_error("fork test grandchild"); + } + + _exit(0); +} + +/* + * Save current register state and compare it to @xbuf1.' + * + * Returns false if @xbuf1 matches the registers. + * Returns true if @xbuf1 differs from the registers. + */ +static inline bool __validate_tiledata_regs(struct xsave_buffer *xbuf1) +{ + struct xsave_buffer *xbuf2; + int ret; + + xbuf2 = alloc_xbuf(); + if (!xbuf2) + fatal_error("failed to allocate XSAVE buffer\n"); + + xsave(xbuf2, XFEATURE_MASK_XTILEDATA); + ret = memcmp(&xbuf1->bytes[xtiledata.xbuf_offset], + &xbuf2->bytes[xtiledata.xbuf_offset], + xtiledata.size); + + free(xbuf2); + + if (ret == 0) + return false; + return true; +} + +static inline void validate_tiledata_regs_same(struct xsave_buffer *xbuf) +{ + int ret = __validate_tiledata_regs(xbuf); + + if (ret != 0) + fatal_error("TILEDATA registers changed"); +} + +static inline void validate_tiledata_regs_changed(struct xsave_buffer *xbuf) +{ + int ret = __validate_tiledata_regs(xbuf); + + if (ret == 0) + fatal_error("TILEDATA registers did not change"); +} + +/* tiledata inheritance test */ + +static void test_fork(void) +{ + pid_t child, grandchild; + + child = fork(); + if (child < 0) { + /* fork() failed */ + fatal_error("fork"); + } else if (child > 0) { + /* fork() succeeded. Now in the parent. */ + int status; + + wait(&status); + if (!WIFEXITED(status) || WEXITSTATUS(status)) + fatal_error("fork test child"); + return; + } + /* fork() succeeded. Now in the child. */ + printf("[RUN]\tCheck tile data inheritance.\n\tBefore fork(), load tiledata\n"); + + load_rand_tiledata(stashed_xsave); + + grandchild = fork(); + if (grandchild < 0) { + /* fork() failed */ + fatal_error("fork"); + } else if (grandchild > 0) { + /* fork() succeeded. Still in the first child. */ + int status; + + wait(&status); + if (!WIFEXITED(status) || WEXITSTATUS(status)) + fatal_error("fork test grand child"); + _exit(0); + } + /* fork() succeeded. Now in the (grand)child. */ + + /* + * TILEDATA registers are not preserved across fork(). + * Ensure that their value has changed: + */ + validate_tiledata_regs_changed(stashed_xsave); + + _exit(0); +} + +/* Context switching test */ + +static struct _ctxtswtest_cfg { + unsigned int iterations; + unsigned int num_threads; +} ctxtswtest_config; + +struct futex_info { + pthread_t thread; + int nr; + pthread_mutex_t mutex; + struct futex_info *next; +}; + +static void *check_tiledata(void *info) +{ + struct futex_info *finfo = (struct futex_info *)info; + struct xsave_buffer *xbuf; + int i; + + xbuf = alloc_xbuf(); + if (!xbuf) + fatal_error("unable to allocate XSAVE buffer"); + + /* + * Load random data into 'xbuf' and then restore + * it to the tile registers themselves. + */ + load_rand_tiledata(xbuf); + for (i = 0; i < ctxtswtest_config.iterations; i++) { + pthread_mutex_lock(&finfo->mutex); + + /* + * Ensure the register values have not + * diverged from those recorded in 'xbuf'. + */ + validate_tiledata_regs_same(xbuf); + + /* Load new, random values into xbuf and registers */ + load_rand_tiledata(xbuf); + + /* + * The last thread's last unlock will be for + * thread 0's mutex. However, thread 0 will + * have already exited the loop and the mutex + * will already be unlocked. + * + * Because this is not an ERRORCHECK mutex, + * that inconsistency will be silently ignored. + */ + pthread_mutex_unlock(&finfo->next->mutex); + } + + free(xbuf); + /* + * Return this thread's finfo, which is + * a unique value for this thread. + */ + return finfo; +} + +static int create_threads(int num, struct futex_info *finfo) +{ + int i; + + for (i = 0; i < num; i++) { + int next_nr; + + finfo[i].nr = i; + /* + * Thread 'i' will wait on this mutex to + * be unlocked. Lock it immediately after + * initialization: + */ + pthread_mutex_init(&finfo[i].mutex, NULL); + pthread_mutex_lock(&finfo[i].mutex); + + next_nr = (i + 1) % num; + finfo[i].next = &finfo[next_nr]; + + if (pthread_create(&finfo[i].thread, NULL, check_tiledata, &finfo[i])) + fatal_error("pthread_create()"); + } + return 0; +} + +static void affinitize_cpu0(void) +{ + cpu_set_t cpuset; + + CPU_ZERO(&cpuset); + CPU_SET(0, &cpuset); + + if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) + fatal_error("sched_setaffinity to CPU 0"); +} + +static void test_context_switch(void) +{ + struct futex_info *finfo; + int i; + + /* Affinitize to one CPU to force context switches */ + affinitize_cpu0(); + + req_xtiledata_perm(); + + printf("[RUN]\tCheck tiledata context switches, %d iterations, %d threads.\n", + ctxtswtest_config.iterations, + ctxtswtest_config.num_threads); + + + finfo = malloc(sizeof(*finfo) * ctxtswtest_config.num_threads); + if (!finfo) + fatal_error("malloc()"); + + create_threads(ctxtswtest_config.num_threads, finfo); + + /* + * This thread wakes up thread 0 + * Thread 0 will wake up 1 + * Thread 1 will wake up 2 + * ... + * the last thread will wake up 0 + * + * ... this will repeat for the configured + * number of iterations. + */ + pthread_mutex_unlock(&finfo[0].mutex); + + /* Wait for all the threads to finish: */ + for (i = 0; i < ctxtswtest_config.num_threads; i++) { + void *thread_retval; + int rc; + + rc = pthread_join(finfo[i].thread, &thread_retval); + + if (rc) + fatal_error("pthread_join() failed for thread %d err: %d\n", + i, rc); + + if (thread_retval != &finfo[i]) + fatal_error("unexpected thread retval for thread %d: %p\n", + i, thread_retval); + + } + + printf("[OK]\tNo incorrect case was found.\n"); + + free(finfo); +} + +int main(void) +{ + /* Check hardware availability at first */ + check_cpuid_xsave(); + check_cpuid_xtiledata(); + + init_stashed_xsave(); + sethandler(SIGILL, handle_noperm, 0); + + test_dynamic_state(); + + /* Request permission for the following tests */ + req_xtiledata_perm(); + + test_fork(); + + ctxtswtest_config.iterations = 10; + ctxtswtest_config.num_threads = 5; + test_context_switch(); + + clearhandler(SIGILL); + free_stashed_xsave(); + + return 0; +}