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