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 extern const unsigned long sys_call_table[];
  14
  15 static inline int syscall_get_nr(struct task_struct *task,
  16                                  struct pt_regs *regs)
  17 {
  18         return task_thread_info(task)->syscall;
  19 }
  20
  21 static inline void syscall_rollback(struct task_struct *task,
  22                                     struct pt_regs *regs)
  23 {
  24         regs->ARM_r0 = regs->ARM_ORIG_r0;
  25 }
  26
  27 static inline long syscall_get_error(struct task_struct *task,
  28                                      struct pt_regs *regs)
  29 {
  30         unsigned long error = regs->ARM_r0;
  31         return IS_ERR_VALUE(error) ? error : 0;
  32 }
  33
  34 static inline long syscall_get_return_value(struct task_struct *task,
  35                                             struct pt_regs *regs)
  36 {
  37         return regs->ARM_r0;
  38 }
  39
  40 static inline void syscall_set_return_value(struct task_struct *task,
  41                                             struct pt_regs *regs,
  42                                             int error, long val)
  43 {
  44         regs->ARM_r0 = (long) error ? error : val;
  45 }
  46
  47 #define SYSCALL_MAX_ARGS 7
  48
  49 static inline void syscall_get_arguments(struct task_struct *task,
  50                                          struct pt_regs *regs,
  51                                          unsigned int i, unsigned int n,
  52                                          unsigned long *args)
  53 {
  54         if (i + n > SYSCALL_MAX_ARGS) {
  55                 unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
  56                 unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
  57                 pr_warning("%s called with max args %d, handling only %d\n",
  58                            __func__, i + n, SYSCALL_MAX_ARGS);
  59                 memset(args_bad, 0, n_bad * sizeof(args[0]));
  60                 n = SYSCALL_MAX_ARGS - i;
  61         }
  62
  63         if (i == 0) {
  64                 args[0] = regs->ARM_ORIG_r0;
  65                 args++;
  66                 i++;
  67                 n--;
  68         }
  69
  70         memcpy(args, &regs->ARM_r0 + i, n * sizeof(args[0]));
  71 }
  72
  73 static inline void syscall_set_arguments(struct task_struct *task,
  74                                          struct pt_regs *regs,
  75                                          unsigned int i, unsigned int n,
  76                                          const unsigned long *args)
  77 {
  78         if (i + n > SYSCALL_MAX_ARGS) {
  79                 pr_warning("%s called with max args %d, handling only %d\n",
  80                            __func__, i + n, SYSCALL_MAX_ARGS);
  81                 n = SYSCALL_MAX_ARGS - i;
  82         }
  83
  84         if (i == 0) {
  85                 regs->ARM_ORIG_r0 = args[0];
  86                 args++;
  87                 i++;
  88                 n--;
  89         }
  90
  91         memcpy(&regs->ARM_r0 + i, args, n * sizeof(args[0]));
  92 }
  93
  94 #endif /* _ASM_ARM_SYSCALL_H */