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
  23typedef long (*syscall_fn_t)(struct pt_regs *regs);
  24
  25extern const syscall_fn_t sys_call_table[];
  26
  27#ifdef CONFIG_COMPAT
  28extern const syscall_fn_t compat_sys_call_table[];
  29#endif
  30
  31static inline int syscall_get_nr(struct task_struct *task,
  32                                 struct pt_regs *regs)
  33{
  34        return regs->syscallno;
  35}
  36
  37static inline void syscall_rollback(struct task_struct *task,
  38                                    struct pt_regs *regs)
  39{
  40        regs->regs[0] = regs->orig_x0;
  41}
  42
  43
  44static inline long syscall_get_error(struct task_struct *task,
  45                                     struct pt_regs *regs)
  46{
  47        unsigned long error = regs->regs[0];
  48        return IS_ERR_VALUE(error) ? error : 0;
  49}
  50
  51static inline long syscall_get_return_value(struct task_struct *task,
  52                                            struct pt_regs *regs)
  53{
  54        return regs->regs[0];
  55}
  56
  57static inline void syscall_set_return_value(struct task_struct *task,
  58                                            struct pt_regs *regs,
  59                                            int error, long val)
  60{
  61        regs->regs[0] = (long) error ? error : val;
  62}
  63
  64#define SYSCALL_MAX_ARGS 6
  65
  66static inline void syscall_get_arguments(struct task_struct *task,
  67                                         struct pt_regs *regs,
  68                                         unsigned int i, unsigned int n,
  69                                         unsigned long *args)
  70{
  71        if (n == 0)
  72                return;
  73
  74        if (i + n > SYSCALL_MAX_ARGS) {
  75                unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
  76                unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
  77                pr_warning("%s called with max args %d, handling only %d\n",
  78                           __func__, i + n, SYSCALL_MAX_ARGS);
  79                memset(args_bad, 0, n_bad * sizeof(args[0]));
  80        }
  81
  82        if (i == 0) {
  83                args[0] = regs->orig_x0;
  84                args++;
  85                i++;
  86                n--;
  87        }
  88
  89        memcpy(args, &regs->regs[i], n * sizeof(args[0]));
  90}
  91
  92static inline void syscall_set_arguments(struct task_struct *task,
  93                                         struct pt_regs *regs,
  94                                         unsigned int i, unsigned int n,
  95                                         const unsigned long *args)
  96{
  97        if (n == 0)
  98                return;
  99
 100        if (i + n > SYSCALL_MAX_ARGS) {
 101                pr_warning("%s called with max args %d, handling only %d\n",
 102                           __func__, i + n, SYSCALL_MAX_ARGS);
 103                n = SYSCALL_MAX_ARGS - i;
 104        }
 105
 106        if (i == 0) {
 107                regs->orig_x0 = args[0];
 108                args++;
 109                i++;
 110                n--;
 111        }
 112
 113        memcpy(&regs->regs[i], args, n * sizeof(args[0]));
 114}
 115
 116/*
 117 * We don't care about endianness (__AUDIT_ARCH_LE bit) here because
 118 * AArch64 has the same system calls both on little- and big- endian.
 119 */
 120static inline int syscall_get_arch(struct task_struct *task)
 121{
 122        if (is_compat_thread(task_thread_info(task)))
 123                return AUDIT_ARCH_ARM;
 124
 125        return AUDIT_ARCH_AARCH64;
 126}
 127
 128#endif  /* __ASM_SYSCALL_H */
 129