arch/arm/include/asm/syscall.h

   1 /*
   2  * Access to user system call parameters and results
   3  *
   4  * See asm-generic/syscall.h for descriptions of what we must do here.
   5  */
   6
   7 #ifndef _ASM_ARM_SYSCALL_H
   8 #define _ASM_ARM_SYSCALL_H
   9
  10 #include <linux/err.h>
  11 #include <linux/sched.h>
  12
  13 #include <asm/unistd.h>
  14
  15 #define NR_syscalls (__NR_syscalls)
  16
  17 extern const unsigned long sys_call_table[];
  18
  19 static inline int syscall_get_nr(struct task_struct *task,
  20                                  struct pt_regs *regs)
  21 {
  22         return task_thread_info(task)->syscall;
  23 }
  24
  25 static inline void syscall_rollback(struct task_struct *task,
  26                                     struct pt_regs *regs)
  27 {
  28         regs->ARM_r0 = regs->ARM_ORIG_r0;
  29 }
  30
  31 static inline long syscall_get_error(struct task_struct *task,
  32                                      struct pt_regs *regs)
  33 {
  34         unsigned long error = regs->ARM_r0;
  35         return IS_ERR_VALUE(error) ? error : 0;
  36 }
  37
  38 static inline long syscall_get_return_value(struct task_struct *task,
  39                                             struct pt_regs *regs)
  40 {
  41         return regs->ARM_r0;
  42 }
  43
  44 static inline void syscall_set_return_value(struct task_struct *task,
  45                                             struct pt_regs *regs,
  46                                             int error, long val)
  47 {
  48         regs->ARM_r0 = (long) error ? error : val;
  49 }
  50
  51 #define SYSCALL_MAX_ARGS 7
  52
  53 static inline void syscall_get_arguments(struct task_struct *task,
  54                                          struct pt_regs *regs,
  55                                          unsigned int i, unsigned int n,
  56                                          unsigned long *args)
  57 {
  58         if (i + n > SYSCALL_MAX_ARGS) {
  59                 unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
  60                 unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
  61                 pr_warning("%s called with max args %d, handling only %d\n",
  62                            __func__, i + n, SYSCALL_MAX_ARGS);
  63                 memset(args_bad, 0, n_bad * sizeof(args[0]));
  64                 n = SYSCALL_MAX_ARGS - i;
  65         }
  66
  67         if (i == 0) {
  68                 args[0] = regs->ARM_ORIG_r0;
  69                 args++;
  70                 i++;
  71                 n--;
  72         }
  73
  74         memcpy(args, &regs->ARM_r0 + i, n * sizeof(args[0]));
  75 }
  76
  77 static inline void syscall_set_arguments(struct task_struct *task,
  78                                          struct pt_regs *regs,
  79                                          unsigned int i, unsigned int n,
  80                                          const unsigned long *args)
  81 {
  82         if (i + n > SYSCALL_MAX_ARGS) {
  83                 pr_warning("%s called with max args %d, handling only %d\n",
  84                            __func__, i + n, SYSCALL_MAX_ARGS);
  85                 n = SYSCALL_MAX_ARGS - i;
  86         }
  87
  88         if (i == 0) {
  89                 regs->ARM_ORIG_r0 = args[0];
  90                 args++;
  91                 i++;
  92                 n--;
  93         }
  94
  95         memcpy(&regs->ARM_r0 + i, args, n * sizeof(args[0]));
  96 }
  97
  98 #endif /* _ASM_ARM_SYSCALL_H */