arch/arm64/include/asm/syscall.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2012 ARM Ltd.
   4  */
   5 #ifndef __ASM_SYSCALL_H
   6 #define __ASM_SYSCALL_H
   7
   8 #include <uapi/linux/audit.h>
   9 #include <linux/compat.h>
  10 #include <linux/err.h>
  11
  12 typedef long (*syscall_fn_t)(const struct pt_regs *regs);
  13
  14 extern const syscall_fn_t sys_call_table[];
  15
  16 #ifdef CONFIG_COMPAT
  17 extern const syscall_fn_t compat_sys_call_table[];
  18 #endif
  19
  20 static inline int syscall_get_nr(struct task_struct *task,
  21                                  struct pt_regs *regs)
  22 {
  23         return regs->syscallno;
  24 }
  25
  26 static inline void syscall_rollback(struct task_struct *task,
  27                                     struct pt_regs *regs)
  28 {
  29         regs->regs[0] = regs->orig_x0;
  30 }
  31
  32 static inline long syscall_get_return_value(struct task_struct *task,
  33                                             struct pt_regs *regs)
  34 {
  35         unsigned long val = regs->regs[0];
  36
  37         if (is_compat_thread(task_thread_info(task)))
  38                 val = sign_extend64(val, 31);
  39
  40         return val;
  41 }
  42
  43 static inline long syscall_get_error(struct task_struct *task,
  44                                      struct pt_regs *regs)
  45 {
  46         unsigned long error = syscall_get_return_value(task, regs);
  47
  48         return IS_ERR_VALUE(error) ? error : 0;
  49 }
  50
  51 static inline void syscall_set_return_value(struct task_struct *task,
  52                                             struct pt_regs *regs,
  53                                             int error, long val)
  54 {
  55         if (error)
  56                 val = error;
  57
  58         if (is_compat_thread(task_thread_info(task)))
  59                 val = lower_32_bits(val);
  60
  61         regs->regs[0] = val;
  62 }
  63
  64 #define SYSCALL_MAX_ARGS 6
  65
  66 static inline void syscall_get_arguments(struct task_struct *task,
  67                                          struct pt_regs *regs,
  68                                          unsigned long *args)
  69 {
  70         args[0] = regs->orig_x0;
  71         args++;
  72
  73         memcpy(args, &regs->regs[1], 5 * sizeof(args[0]));
  74 }
  75
  76 /*
  77  * We don't care about endianness (__AUDIT_ARCH_LE bit) here because
  78  * AArch64 has the same system calls both on little- and big- endian.
  79  */
  80 static inline int syscall_get_arch(struct task_struct *task)
  81 {
  82         if (is_compat_thread(task_thread_info(task)))
  83                 return AUDIT_ARCH_ARM;
  84
  85         return AUDIT_ARCH_AARCH64;
  86 }
  87
  88 int syscall_trace_enter(struct pt_regs *regs);
  89 void syscall_trace_exit(struct pt_regs *regs);
  90
  91 #endif  /* __ASM_SYSCALL_H */