LXR linux/arch/x86/include/asm/syscall.h

   1/*
   2 * Access to user system call parameters and results
   3 *
   4 * Copyright (C) 2008-2009 Red Hat, Inc.  All rights reserved.
   5 *
   6 * This copyrighted material is made available to anyone wishing to use,
   7 * modify, copy, or redistribute it subject to the terms and conditions
   8 * of the GNU General Public License v.2.
   9 *
  10 * See asm-generic/syscall.h for descriptions of what we must do here.
  11 */
  12
  13#ifndef _ASM_X86_SYSCALL_H
  14#define _ASM_X86_SYSCALL_H
  15
  16#include <linux/sched.h>
  17#include <linux/err.h>
  18
  19/*
  20 * Only the low 32 bits of orig_ax are meaningful, so we return int.
  21 * This importantly ignores the high bits on 64-bit, so comparisons
  22 * sign-extend the low 32 bits.
  23 */
  24static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
  25{
  26        return regs->orig_ax;
  27}
  28
  29static inline void syscall_rollback(struct task_struct *task,
  30                                    struct pt_regs *regs)
  31{
  32        regs->ax = regs->orig_ax;
  33}
  34
  35static inline long syscall_get_error(struct task_struct *task,
  36                                     struct pt_regs *regs)
  37{
  38        unsigned long error = regs->ax;
  39#ifdef CONFIG_IA32_EMULATION
  40        /*
  41         * TS_COMPAT is set for 32-bit syscall entries and then
  42         * remains set until we return to user mode.
  43         */
  44        if (task_thread_info(task)->status & TS_COMPAT)
  45                /*
  46                 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
  47                 * and will match correctly in comparisons.
  48                 */
  49                error = (long) (int) error;
  50#endif
  51        return IS_ERR_VALUE(error) ? error : 0;
  52}
  53
  54static inline long syscall_get_return_value(struct task_struct *task,
  55                                            struct pt_regs *regs)
  56{
  57        return regs->ax;
  58}
  59
  60static inline void syscall_set_return_value(struct task_struct *task,
  61                                            struct pt_regs *regs,
  62                                            int error, long val)
  63{
  64        regs->ax = (long) error ?: val;
  65}
  66
  67#ifdef CONFIG_X86_32
  68
  69static inline void syscall_get_arguments(struct task_struct *task,
  70                                         struct pt_regs *regs,
  71                                         unsigned int i, unsigned int n,
  72                                         unsigned long *args)
  73{
  74        BUG_ON(i + n > 6);
  75        memcpy(args, &regs->bx + i, n * sizeof(args[0]));
  76}
  77
  78static inline void syscall_set_arguments(struct task_struct *task,
  79                                         struct pt_regs *regs,
  80                                         unsigned int i, unsigned int n,
  81                                         const unsigned long *args)
  82{
  83        BUG_ON(i + n > 6);
  84        memcpy(&regs->bx + i, args, n * sizeof(args[0]));
  85}
  86
  87#else    /* CONFIG_X86_64 */
  88
  89static inline void syscall_get_arguments(struct task_struct *task,
  90                                         struct pt_regs *regs,
  91                                         unsigned int i, unsigned int n,
  92                                         unsigned long *args)
  93{
  94# ifdef CONFIG_IA32_EMULATION
  95        if (task_thread_info(task)->status & TS_COMPAT)
  96                switch (i) {
  97                case 0:
  98                        if (!n--) break;
  99                        *args++ = regs->bx;
 100                case 1:
 101                        if (!n--) break;
 102                        *args++ = regs->cx;
 103                case 2:
 104                        if (!n--) break;
 105                        *args++ = regs->dx;
 106                case 3:
 107                        if (!n--) break;
 108                        *args++ = regs->si;
 109                case 4:
 110                        if (!n--) break;
 111                        *args++ = regs->di;
 112                case 5:
 113                        if (!n--) break;
 114                        *args++ = regs->bp;
 115                case 6:
 116                        if (!n--) break;
 117                default:
 118                        BUG();
 119                        break;
 120                }
 121        else
 122# endif
 123                switch (i) {
 124                case 0:
 125                        if (!n--) break;
 126                        *args++ = regs->di;
 127                case 1:
 128                        if (!n--) break;
 129                        *args++ = regs->si;
 130                case 2:
 131                        if (!n--) break;
 132                        *args++ = regs->dx;
 133                case 3:
 134                        if (!n--) break;
 135                        *args++ = regs->r10;
 136                case 4:
 137                        if (!n--) break;
 138                        *args++ = regs->r8;
 139                case 5:
 140                        if (!n--) break;
 141                        *args++ = regs->r9;
 142                case 6:
 143                        if (!n--) break;
 144                default:
 145                        BUG();
 146                        break;
 147                }
 148}
 149
 150static inline void syscall_set_arguments(struct task_struct *task,
 151                                         struct pt_regs *regs,
 152                                         unsigned int i, unsigned int n,
 153                                         const unsigned long *args)
 154{
 155# ifdef CONFIG_IA32_EMULATION
 156        if (task_thread_info(task)->status & TS_COMPAT)
 157                switch (i) {
 158                case 0:
 159                        if (!n--) break;
 160                        regs->bx = *args++;
 161                case 1:
 162                        if (!n--) break;
 163                        regs->cx = *args++;
 164                case 2:
 165                        if (!n--) break;
 166                        regs->dx = *args++;
 167                case 3:
 168                        if (!n--) break;
 169                        regs->si = *args++;
 170                case 4:
 171                        if (!n--) break;
 172                        regs->di = *args++;
 173                case 5:
 174                        if (!n--) break;
 175                        regs->bp = *args++;
 176                case 6:
 177                        if (!n--) break;
 178                default:
 179                        BUG();
 180                        break;
 181                }
 182        else
 183# endif
 184                switch (i) {
 185                case 0:
 186                        if (!n--) break;
 187                        regs->di = *args++;
 188                case 1:
 189                        if (!n--) break;
 190                        regs->si = *args++;
 191                case 2:
 192                        if (!n--) break;
 193                        regs->dx = *args++;
 194                case 3:
 195                        if (!n--) break;
 196                        regs->r10 = *args++;
 197                case 4:
 198                        if (!n--) break;
 199                        regs->r8 = *args++;
 200                case 5:
 201                        if (!n--) break;
 202                        regs->r9 = *args++;
 203                case 6:
 204                        if (!n--) break;
 205                default:
 206                        BUG();
 207                        break;
 208                }
 209}
 210
 211#endif  /* CONFIG_X86_32 */
 212
 213#endif  /* _ASM_X86_SYSCALL_H */
 214