arch/arm64/include/asm/syscall.h

   1 /*
   2  * Copyright (C) 2012 ARM Ltd.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16 #ifndef __ASM_SYSCALL_H
  17 #define __ASM_SYSCALL_H
  18
  19 #include <linux/err.h>
  20
  21
  22 static inline int syscall_get_nr(struct task_struct *task,
  23                                  struct pt_regs *regs)
  24 {
  25         return regs->syscallno;
  26 }
  27
  28 static inline void syscall_rollback(struct task_struct *task,
  29                                     struct pt_regs *regs)
  30 {
  31         regs->regs[0] = regs->orig_x0;
  32 }
  33
  34
  35 static inline long syscall_get_error(struct task_struct *task,
  36                                      struct pt_regs *regs)
  37 {
  38         unsigned long error = regs->regs[0];
  39         return IS_ERR_VALUE(error) ? error : 0;
  40 }
  41
  42 static inline long syscall_get_return_value(struct task_struct *task,
  43                                             struct pt_regs *regs)
  44 {
  45         return regs->regs[0];
  46 }
  47
  48 static inline void syscall_set_return_value(struct task_struct *task,
  49                                             struct pt_regs *regs,
  50                                             int error, long val)
  51 {
  52         regs->regs[0] = (long) error ? error : val;
  53 }
  54
  55 #define SYSCALL_MAX_ARGS 6
  56
  57 static inline void syscall_get_arguments(struct task_struct *task,
  58                                          struct pt_regs *regs,
  59                                          unsigned int i, unsigned int n,
  60                                          unsigned long *args)
  61 {
  62         if (n == 0)
  63                 return;
  64
  65         if (i + n > SYSCALL_MAX_ARGS) {
  66                 unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
  67                 unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
  68                 pr_warning("%s called with max args %d, handling only %d\n",
  69                            __func__, i + n, SYSCALL_MAX_ARGS);
  70                 memset(args_bad, 0, n_bad * sizeof(args[0]));
  71         }
  72
  73         if (i == 0) {
  74                 args[0] = regs->orig_x0;
  75                 args++;
  76                 i++;
  77                 n--;
  78         }
  79
  80         memcpy(args, &regs->regs[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_warning("%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->orig_x0 = args[0];
  99                 args++;
 100                 i++;
 101                 n--;
 102         }
 103
 104         memcpy(&regs->regs[i], args, n * sizeof(args[0]));
 105 }
 106
 107 #endif  /* __ASM_SYSCALL_H */