projects/linux·commit cef6c8c9

Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

cef6c8c9 · Linus Torvalds <[email protected]> · 2025-07-24 08:50:55 -07:00

Pull arm64 fixes from Will Deacon:
 "Two important arm64 fixes ahead of the 6.16 release.

  The first fixes a regression introduced during the merge window where
  the KVM UUID (which is used to advertise KVM-specific hypercalls for
  things like time synchronisation in the guest) was corrupted thanks to
  an endianness bug introduced when converting the code to use the
  UUID_INIT() helper.

  The second fixes a stack-pointer corruption issue during
  context-switch which has been observed in the wild when taking a
  pseudo-NMI with shadow call stack enabled.

  Summary:

   - Fix broken UUID value for the KVM/arm64 hypervisor SMCCC interface

   - Fix stack corruption on context-switch, primarily seen on (but not
     limited to) configurations with both pNMI and SCS enabled"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64/entry: Mask DAIF in cpu_switch_to(), call_on_irq_stack()
  arm64: kvm, smccc: Fix vendor uuid
Commit
cef6c8c92fafa58fa04d8622e89ed4871d121fc3
Parents
407c114c · d42e6c20

Merge commit. Changes below are compared with the first parent: 407c114c.

Changes

3 files changed · +12 −1

FileStatusAddDelContent
arch/arm64/include/asm/assembler.hmodified+5−0View file
arch/arm64/kernel/entry.Smodified+6−0View file
include/linux/arm-smccc.hmodified+1−1View file

arch/arm64/include/asm/assembler.h

View file
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index ad63457..c56c21b 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -41,6 +41,11 @@
/*
* Save/restore interrupts.
*/
+ .macro save_and_disable_daif, flags
+ mrs \flags, daif
+ msr daifset, #0xf
+ .endm
+
.macro save_and_disable_irq, flags
mrs \flags, daif
msr daifset, #3

arch/arm64/kernel/entry.S

View file
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 5ae2a34..30dcb71 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -825,6 +825,7 @@ SYM_CODE_END(__bp_harden_el1_vectors)
*
*/
SYM_FUNC_START(cpu_switch_to)
+ save_and_disable_daif x11
mov x10, #THREAD_CPU_CONTEXT
add x8, x0, x10
mov x9, sp
@@ -848,6 +849,7 @@ SYM_FUNC_START(cpu_switch_to)
ptrauth_keys_install_kernel x1, x8, x9, x10
scs_save x0
scs_load_current
+ restore_irq x11
ret
SYM_FUNC_END(cpu_switch_to)
NOKPROBE(cpu_switch_to)
@@ -874,6 +876,7 @@ NOKPROBE(ret_from_fork)
* Calls func(regs) using this CPU's irq stack and shadow irq stack.
*/
SYM_FUNC_START(call_on_irq_stack)
+ save_and_disable_daif x9
#ifdef CONFIG_SHADOW_CALL_STACK
get_current_task x16
scs_save x16
@@ -888,8 +891,10 @@ SYM_FUNC_START(call_on_irq_stack)
/* Move to the new stack and call the function there */
add sp, x16, #IRQ_STACK_SIZE
+ restore_irq x9
blr x1
+ save_and_disable_daif x9
/*
* Restore the SP from the FP, and restore the FP and LR from the frame
* record.
@@ -897,6 +902,7 @@ SYM_FUNC_START(call_on_irq_stack)
mov sp, x29
ldp x29, x30, [sp], #16
scs_load_current
+ restore_irq x9
ret
SYM_FUNC_END(call_on_irq_stack)
NOKPROBE(call_on_irq_stack)

include/linux/arm-smccc.h

View file
diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index 784ebe4..50b47eb 100644
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
@@ -113,7 +113,7 @@
/* KVM UID value: 28b46fb6-2ec5-11e9-a9ca-4b564d003a74 */
#define ARM_SMCCC_VENDOR_HYP_UID_KVM UUID_INIT(\
- 0xb66fb428, 0xc52e, 0xe911, \
+ 0x28b46fb6, 0x2ec5, 0x11e9, \
0xa9, 0xca, 0x4b, 0x56, \
0x4d, 0x00, 0x3a, 0x74)