arch/arm/include/asm/syscall.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Access to user system call parameters and results
   4  *
   5  * See asm-generic/syscall.h for descriptions of what we must do here.
   6  */
   7
   8 #ifndef _ASM_ARM_SYSCALL_H
   9 #define _ASM_ARM_SYSCALL_H
  10
  11 #include <uapi/linux/audit.h> /* for AUDIT_ARCH_* */
  12 #include <linux/elf.h> /* for ELF_EM */
  13 #include <linux/err.h>
  14 #include <linux/sched.h>
  15
  16 #include <asm/unistd.h>
  17
  18 #define NR_syscalls (__NR_syscalls)
  19
  20 extern const unsigned long sys_call_table[];
  21
  22 static inline int syscall_get_nr(struct task_struct *task,
  23                                  struct pt_regs *regs)
  24 {
  25         return task_thread_info(task)->syscall;
  26 }
  27
  28 static inline void syscall_rollback(struct task_struct *task,
  29                                     struct pt_regs *regs)
  30 {
  31         regs->ARM_r0 = regs->ARM_ORIG_r0;
  32 }
  33
  34 static inline long syscall_get_error(struct task_struct *task,
  35                                      struct pt_regs *regs)
  36 {
  37         unsigned long error = regs->ARM_r0;
  38         return IS_ERR_VALUE(error) ? error : 0;
  39 }
  40
  41 static inline long syscall_get_return_value(struct task_struct *task,
  42                                             struct pt_regs *regs)
  43 {
  44         return regs->ARM_r0;
  45 }
  46
  47 static inline void syscall_set_return_value(struct task_struct *task,
  48                                             struct pt_regs *regs,
  49                                             int error, long val)
  50 {
  51         regs->ARM_r0 = (long) error ? error : val;
  52 }
  53
  54 #define SYSCALL_MAX_ARGS 7
  55
  56 static inline void syscall_get_arguments(struct task_struct *task,
  57                                          struct pt_regs *regs,
  58                                          unsigned int i, unsigned int n,
  59                                          unsigned long *args)
  60 {
  61         if (n == 0)
  62                 return;
  63
  64         if (i + n > SYSCALL_MAX_ARGS) {
  65                 unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
  66                 unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
  67                 pr_warn("%s called with max args %d, handling only %d\n",
  68                         __func__, i + n, SYSCALL_MAX_ARGS);
  69                 memset(args_bad, 0, n_bad * sizeof(args[0]));
  70                 n = SYSCALL_MAX_ARGS - i;
  71         }
  72
  73         if (i == 0) {
  74                 args[0] = regs->ARM_ORIG_r0;
  75                 args++;
  76                 i++;
  77                 n--;
  78         }
  79
  80         memcpy(args, &regs->ARM_r0 + i, n * sizeof(args[0]));
  81 }
  82
  83 static inline void syscall_set_arguments(struct task_struct *task,
  84                                          struct pt_regs *regs,
  85                                          unsigned int i, unsigned int n,
  86                                          const unsigned long *args)
  87 {
  88         if (n == 0)
  89                 return;
  90
  91         if (i + n > SYSCALL_MAX_ARGS) {
  92                 pr_warn("%s called with max args %d, handling only %d\n",
  93                         __func__, i + n, SYSCALL_MAX_ARGS);
  94                 n = SYSCALL_MAX_ARGS - i;
  95         }
  96
  97         if (i == 0) {
  98                 regs->ARM_ORIG_r0 = args[0];
  99                 args++;
 100                 i++;
 101                 n--;
 102         }
 103
 104         memcpy(&regs->ARM_r0 + i, args, n * sizeof(args[0]));
 105 }
 106
 107 static inline int syscall_get_arch(void)
 108 {
 109         /* ARM tasks don't change audit architectures on the fly. */
 110         return AUDIT_ARCH_ARM;
 111 }
 112
 113 #endif /* _ASM_ARM_SYSCALL_H */