| 1 |
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| 2 | |
| 3 | * Copyright (C) 2012 ARM Ltd.
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| 4 |
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| 5 | #ifndef __ASM_SYSCALL_H
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| 6 | #define __ASM_SYSCALL_H
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| 7 |
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| 8 | #include <uapi/linux/audit.h>
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| 9 | #include <linux/compat.h>
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| 10 | #include <linux/err.h>
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| 11 |
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| 12 | typedef long (*syscall_fn_t)(const struct pt_regs *regs);
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| 13 |
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| 14 | extern const syscall_fn_t sys_call_table[];
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| 15 |
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| 16 | #ifdef CONFIG_COMPAT
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| 17 | extern const syscall_fn_t compat_sys_call_table[];
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| 18 | #endif
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| 19 |
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| 20 | static inline int syscall_get_nr(struct task_struct *task,
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| 21 | struct pt_regs *regs)
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| 22 | {
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| 23 | return regs->syscallno;
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| 24 | }
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| 25 |
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| 26 | static inline void syscall_rollback(struct task_struct *task,
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| 27 | struct pt_regs *regs)
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| 28 | {
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| 29 | regs->regs[0] = regs->orig_x0;
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| 30 | }
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| 31 |
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| 32 | static inline long syscall_get_return_value(struct task_struct *task,
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| 33 | struct pt_regs *regs)
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| 34 | {
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| 35 | unsigned long val = regs->regs[0];
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| 36 |
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| 37 | if (is_compat_thread(task_thread_info(task)))
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| 38 | val = sign_extend64(val, 31);
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| 39 |
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| 40 | return val;
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| 41 | }
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| 42 |
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| 43 | static inline long syscall_get_error(struct task_struct *task,
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| 44 | struct pt_regs *regs)
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| 45 | {
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| 46 | unsigned long error = syscall_get_return_value(task, regs);
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| 47 |
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| 48 | return IS_ERR_VALUE(error) ? error : 0;
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| 49 | }
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| 50 |
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| 51 | static inline void syscall_set_return_value(struct task_struct *task,
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| 52 | struct pt_regs *regs,
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| 53 | int error, long val)
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| 54 | {
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| 55 | if (error)
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| 56 | val = error;
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| 57 |
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| 58 | if (is_compat_thread(task_thread_info(task)))
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| 59 | val = lower_32_bits(val);
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| 60 |
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| 61 | regs->regs[0] = val;
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| 62 | }
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| 63 |
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| 64 | static inline void syscall_set_nr(struct task_struct *task,
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| 65 | struct pt_regs *regs,
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| 66 | int nr)
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| 67 | {
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| 68 | regs->syscallno = nr;
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| 69 | if (nr == -1) {
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| 70 | |
| 71 | * When the syscall number is set to -1, the syscall will be
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| 72 | * skipped. In this case the syscall return value has to be
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| 73 | * set explicitly, otherwise the first syscall argument is
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| 74 | * returned as the syscall return value.
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| 75 |
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| 76 | syscall_set_return_value(task, regs, -ENOSYS, 0);
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| 77 | }
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| 78 | }
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| 79 |
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| 80 | static inline void syscall_get_arguments(struct task_struct *task,
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| 81 | struct pt_regs *regs,
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| 82 | unsigned long *args)
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| 83 | {
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| 84 | args[0] = regs->orig_x0;
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| 85 | args[1] = regs->regs[1];
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| 86 | args[2] = regs->regs[2];
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| 87 | args[3] = regs->regs[3];
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| 88 | args[4] = regs->regs[4];
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| 89 | args[5] = regs->regs[5];
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| 90 | }
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| 91 |
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| 92 | static inline void syscall_set_arguments(struct task_struct *task,
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| 93 | struct pt_regs *regs,
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| 94 | const unsigned long *args)
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| 95 | {
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| 96 | regs->regs[0] = args[0];
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| 97 | regs->regs[1] = args[1];
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| 98 | regs->regs[2] = args[2];
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| 99 | regs->regs[3] = args[3];
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| 100 | regs->regs[4] = args[4];
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| 101 | regs->regs[5] = args[5];
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| 102 |
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| 103 | |
| 104 | * Also copy the first argument into orig_x0
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| 105 | * so that syscall_get_arguments() would return it
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| 106 | * instead of the previous value.
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| 107 |
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| 108 | regs->orig_x0 = regs->regs[0];
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| 109 | }
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| 110 |
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| 111 | |
| 112 | * We don't care about endianness (__AUDIT_ARCH_LE bit) here because
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| 113 | * AArch64 has the same system calls both on little- and big- endian.
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| 114 |
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| 115 | static inline int syscall_get_arch(struct task_struct *task)
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| 116 | {
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| 117 | if (is_compat_thread(task_thread_info(task)))
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| 118 | return AUDIT_ARCH_ARM;
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| 119 |
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| 120 | return AUDIT_ARCH_AARCH64;
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| 121 | }
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| 122 |
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| 123 | int syscall_trace_enter(struct pt_regs *regs);
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| 124 | void syscall_trace_exit(struct pt_regs *regs);
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| 125 |
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| 126 | #endif
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