LXR linux/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 <uapi/linux/audit.h>
  20#include <linux/compat.h>
  21#include <linux/err.h>
  22
  23extern const void *sys_call_table[];
  24
  25static inline int syscall_get_nr(struct task_struct *task,
  26                                 struct pt_regs *regs)
  27{
  28        return regs->syscallno;
  29}
  30
  31static inline void syscall_rollback(struct task_struct *task,
  32                                    struct pt_regs *regs)
  33{
  34        regs->regs[0] = regs->orig_x0;
  35}
  36
  37
  38static inline long syscall_get_error(struct task_struct *task,
  39                                     struct pt_regs *regs)
  40{
  41        unsigned long error = regs->regs[0];
  42        return IS_ERR_VALUE(error) ? error : 0;
  43}
  44
  45static inline long syscall_get_return_value(struct task_struct *task,
  46                                            struct pt_regs *regs)
  47{
  48        return regs->regs[0];
  49}
  50
  51static inline void syscall_set_return_value(struct task_struct *task,
  52                                            struct pt_regs *regs,
  53                                            int error, long val)
  54{
  55        regs->regs[0] = (long) error ? error : val;
  56}
  57
  58#define SYSCALL_MAX_ARGS 6
  59
  60static inline void syscall_get_arguments(struct task_struct *task,
  61                                         struct pt_regs *regs,
  62                                         unsigned int i, unsigned int n,
  63                                         unsigned long *args)
  64{
  65        if (n == 0)
  66                return;
  67
  68        if (i + n > SYSCALL_MAX_ARGS) {
  69                unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
  70                unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
  71                pr_warning("%s called with max args %d, handling only %d\n",
  72                           __func__, i + n, SYSCALL_MAX_ARGS);
  73                memset(args_bad, 0, n_bad * sizeof(args[0]));
  74        }
  75
  76        if (i == 0) {
  77                args[0] = regs->orig_x0;
  78                args++;
  79                i++;
  80                n--;
  81        }
  82
  83        memcpy(args, &regs->regs[i], n * sizeof(args[0]));
  84}
  85
  86static inline void syscall_set_arguments(struct task_struct *task,
  87                                         struct pt_regs *regs,
  88                                         unsigned int i, unsigned int n,
  89                                         const unsigned long *args)
  90{
  91        if (n == 0)
  92                return;
  93
  94        if (i + n > SYSCALL_MAX_ARGS) {
  95                pr_warning("%s called with max args %d, handling only %d\n",
  96                           __func__, i + n, SYSCALL_MAX_ARGS);
  97                n = SYSCALL_MAX_ARGS - i;
  98        }
  99
 100        if (i == 0) {
 101                regs->orig_x0 = args[0];
 102                args++;
 103                i++;
 104                n--;
 105        }
 106
 107        memcpy(&regs->regs[i], args, n * sizeof(args[0]));
 108}
 109
 110/*
 111 * We don't care about endianness (__AUDIT_ARCH_LE bit) here because
 112 * AArch64 has the same system calls both on little- and big- endian.
 113 */
 114static inline int syscall_get_arch(void)
 115{
 116        if (is_compat_task())
 117                return AUDIT_ARCH_ARM;
 118
 119        return AUDIT_ARCH_AARCH64;
 120}
 121
 122#endif  /* __ASM_SYSCALL_H */
 123