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 (i + n > SYSCALL_MAX_ARGS) {
  63                 unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
  64                 unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
  65                 pr_warning("%s called with max args %d, handling only %d\n",
  66                            __func__, i + n, SYSCALL_MAX_ARGS);
  67                 memset(args_bad, 0, n_bad * sizeof(args[0]));
  68         }
  69
  70         if (i == 0) {
  71                 args[0] = regs->orig_x0;
  72                 args++;
  73                 i++;
  74                 n--;
  75         }
  76
  77         memcpy(args, &regs->regs[i], n * sizeof(args[0]));
  78 }
  79
  80 static inline void syscall_set_arguments(struct task_struct *task,
  81                                          struct pt_regs *regs,
  82                                          unsigned int i, unsigned int n,
  83                                          const unsigned long *args)
  84 {
  85         if (i + n > SYSCALL_MAX_ARGS) {
  86                 pr_warning("%s called with max args %d, handling only %d\n",
  87                            __func__, i + n, SYSCALL_MAX_ARGS);
  88                 n = SYSCALL_MAX_ARGS - i;
  89         }
  90
  91         if (i == 0) {
  92                 regs->orig_x0 = args[0];
  93                 args++;
  94                 i++;
  95                 n--;
  96         }
  97
  98         memcpy(&regs->regs[i], args, n * sizeof(args[0]));
  99 }
 100
 101 #endif  /* __ASM_SYSCALL_H */