LXR linux/arch/mips/include/asm/syscall.h

   1/*
   2 * Access to user system call parameters and results
   3 *
   4 * This file is subject to the terms and conditions of the GNU General Public
   5 * License.  See the file "COPYING" in the main directory of this archive
   6 * for more details.
   7 *
   8 * See asm-generic/syscall.h for descriptions of what we must do here.
   9 *
  10 * Copyright (C) 2012 Ralf Baechle <ralf@linux-mips.org>
  11 */
  12
  13#ifndef __ASM_MIPS_SYSCALL_H
  14#define __ASM_MIPS_SYSCALL_H
  15
  16#include <linux/compiler.h>
  17#include <uapi/linux/audit.h>
  18#include <linux/elf-em.h>
  19#include <linux/kernel.h>
  20#include <linux/sched.h>
  21#include <linux/uaccess.h>
  22#include <asm/ptrace.h>
  23#include <asm/unistd.h>
  24
  25#ifndef __NR_syscall /* Only defined if _MIPS_SIM == _MIPS_SIM_ABI32 */
  26#define __NR_syscall 4000
  27#endif
  28
  29static inline long syscall_get_nr(struct task_struct *task,
  30                                  struct pt_regs *regs)
  31{
  32        return current_thread_info()->syscall;
  33}
  34
  35static inline unsigned long mips_get_syscall_arg(unsigned long *arg,
  36        struct task_struct *task, struct pt_regs *regs, unsigned int n)
  37{
  38        unsigned long usp __maybe_unused = regs->regs[29];
  39
  40        switch (n) {
  41        case 0: case 1: case 2: case 3:
  42                *arg = regs->regs[4 + n];
  43
  44                return 0;
  45
  46#ifdef CONFIG_32BIT
  47        case 4: case 5: case 6: case 7:
  48                return get_user(*arg, (int *)usp + n);
  49#endif
  50
  51#ifdef CONFIG_64BIT
  52        case 4: case 5: case 6: case 7:
  53#ifdef CONFIG_MIPS32_O32
  54                if (test_thread_flag(TIF_32BIT_REGS))
  55                        return get_user(*arg, (int *)usp + n);
  56                else
  57#endif
  58                        *arg = regs->regs[4 + n];
  59
  60                return 0;
  61#endif
  62
  63        default:
  64                BUG();
  65        }
  66
  67        unreachable();
  68}
  69
  70static inline long syscall_get_return_value(struct task_struct *task,
  71                                            struct pt_regs *regs)
  72{
  73        return regs->regs[2];
  74}
  75
  76static inline void syscall_rollback(struct task_struct *task,
  77                                    struct pt_regs *regs)
  78{
  79        /* Do nothing */
  80}
  81
  82static inline void syscall_set_return_value(struct task_struct *task,
  83                                            struct pt_regs *regs,
  84                                            int error, long val)
  85{
  86        if (error) {
  87                regs->regs[2] = -error;
  88                regs->regs[7] = -1;
  89        } else {
  90                regs->regs[2] = val;
  91                regs->regs[7] = 0;
  92        }
  93}
  94
  95static inline void syscall_get_arguments(struct task_struct *task,
  96                                         struct pt_regs *regs,
  97                                         unsigned int i, unsigned int n,
  98                                         unsigned long *args)
  99{
 100        int ret;
 101        /* O32 ABI syscall() - Either 64-bit with O32 or 32-bit */
 102        if ((config_enabled(CONFIG_32BIT) ||
 103            test_tsk_thread_flag(task, TIF_32BIT_REGS)) &&
 104            (regs->regs[2] == __NR_syscall))
 105                i++;
 106
 107        while (n--)
 108                ret |= mips_get_syscall_arg(args++, task, regs, i++);
 109
 110        /*
 111         * No way to communicate an error because this is a void function.
 112         */
 113#if 0
 114        return ret;
 115#endif
 116}
 117
 118extern const unsigned long sys_call_table[];
 119extern const unsigned long sys32_call_table[];
 120extern const unsigned long sysn32_call_table[];
 121
 122static inline int syscall_get_arch(void)
 123{
 124        int arch = AUDIT_ARCH_MIPS;
 125#ifdef CONFIG_64BIT
 126        if (!test_thread_flag(TIF_32BIT_REGS)) {
 127                arch |= __AUDIT_ARCH_64BIT;
 128                /* N32 sets only TIF_32BIT_ADDR */
 129                if (test_thread_flag(TIF_32BIT_ADDR))
 130                        arch |= __AUDIT_ARCH_CONVENTION_MIPS64_N32;
 131        }
 132#endif
 133#if defined(__LITTLE_ENDIAN)
 134        arch |=  __AUDIT_ARCH_LE;
 135#endif
 136        return arch;
 137}
 138
 139#endif  /* __ASM_MIPS_SYSCALL_H */
 140