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/audit.h>
  17#include <linux/sched.h>
  18#include <linux/err.h>
  19#include <asm/asm-offsets.h>    /* For NR_syscalls */
  20#include <asm/thread_info.h>    /* for TS_COMPAT */
  21#include <asm/unistd.h>
  22
  23extern const unsigned long sys_call_table[];
  24
  25/*
  26 * Only the low 32 bits of orig_ax are meaningful, so we return int.
  27 * This importantly ignores the high bits on 64-bit, so comparisons
  28 * sign-extend the low 32 bits.
  29 */
  30static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
  31{
  32        return regs->orig_ax & __SYSCALL_MASK;
  33}
  34
  35static inline void syscall_rollback(struct task_struct *task,
  36                                    struct pt_regs *regs)
  37{
  38        regs->ax = regs->orig_ax & __SYSCALL_MASK;
  39}
  40
  41static inline long syscall_get_error(struct task_struct *task,
  42                                     struct pt_regs *regs)
  43{
  44        unsigned long error = regs->ax;
  45#ifdef CONFIG_IA32_EMULATION
  46        /*
  47         * TS_COMPAT is set for 32-bit syscall entries and then
  48         * remains set until we return to user mode.
  49         */
  50        if (task_thread_info(task)->status & TS_COMPAT)
  51                /*
  52                 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
  53                 * and will match correctly in comparisons.
  54                 */
  55                error = (long) (int) error;
  56#endif
  57        return IS_ERR_VALUE(error) ? error : 0;
  58}
  59
  60static inline long syscall_get_return_value(struct task_struct *task,
  61                                            struct pt_regs *regs)
  62{
  63        return regs->ax;
  64}
  65
  66static inline void syscall_set_return_value(struct task_struct *task,
  67                                            struct pt_regs *regs,
  68                                            int error, long val)
  69{
  70        regs->ax = (long) error ?: val;
  71}
  72
  73#ifdef CONFIG_X86_32
  74
  75static inline void syscall_get_arguments(struct task_struct *task,
  76                                         struct pt_regs *regs,
  77                                         unsigned int i, unsigned int n,
  78                                         unsigned long *args)
  79{
  80        BUG_ON(i + n > 6);
  81        memcpy(args, &regs->bx + i, n * sizeof(args[0]));
  82}
  83
  84static inline void syscall_set_arguments(struct task_struct *task,
  85                                         struct pt_regs *regs,
  86                                         unsigned int i, unsigned int n,
  87                                         const unsigned long *args)
  88{
  89        BUG_ON(i + n > 6);
  90        memcpy(&regs->bx + i, args, n * sizeof(args[0]));
  91}
  92
  93static inline int syscall_get_arch(struct task_struct *task,
  94                                   struct pt_regs *regs)
  95{
  96        return AUDIT_ARCH_I386;
  97}
  98
  99#else    /* CONFIG_X86_64 */
 100
 101static inline void syscall_get_arguments(struct task_struct *task,
 102                                         struct pt_regs *regs,
 103                                         unsigned int i, unsigned int n,
 104                                         unsigned long *args)
 105{
 106# ifdef CONFIG_IA32_EMULATION
 107        if (task_thread_info(task)->status & TS_COMPAT)
 108                switch (i) {
 109                case 0:
 110                        if (!n--) break;
 111                        *args++ = regs->bx;
 112                case 1:
 113                        if (!n--) break;
 114                        *args++ = regs->cx;
 115                case 2:
 116                        if (!n--) break;
 117                        *args++ = regs->dx;
 118                case 3:
 119                        if (!n--) break;
 120                        *args++ = regs->si;
 121                case 4:
 122                        if (!n--) break;
 123                        *args++ = regs->di;
 124                case 5:
 125                        if (!n--) break;
 126                        *args++ = regs->bp;
 127                case 6:
 128                        if (!n--) break;
 129                default:
 130                        BUG();
 131                        break;
 132                }
 133        else
 134# endif
 135                switch (i) {
 136                case 0:
 137                        if (!n--) break;
 138                        *args++ = regs->di;
 139                case 1:
 140                        if (!n--) break;
 141                        *args++ = regs->si;
 142                case 2:
 143                        if (!n--) break;
 144                        *args++ = regs->dx;
 145                case 3:
 146                        if (!n--) break;
 147                        *args++ = regs->r10;
 148                case 4:
 149                        if (!n--) break;
 150                        *args++ = regs->r8;
 151                case 5:
 152                        if (!n--) break;
 153                        *args++ = regs->r9;
 154                case 6:
 155                        if (!n--) break;
 156                default:
 157                        BUG();
 158                        break;
 159                }
 160}
 161
 162static inline void syscall_set_arguments(struct task_struct *task,
 163                                         struct pt_regs *regs,
 164                                         unsigned int i, unsigned int n,
 165                                         const unsigned long *args)
 166{
 167# ifdef CONFIG_IA32_EMULATION
 168        if (task_thread_info(task)->status & TS_COMPAT)
 169                switch (i) {
 170                case 0:
 171                        if (!n--) break;
 172                        regs->bx = *args++;
 173                case 1:
 174                        if (!n--) break;
 175                        regs->cx = *args++;
 176                case 2:
 177                        if (!n--) break;
 178                        regs->dx = *args++;
 179                case 3:
 180                        if (!n--) break;
 181                        regs->si = *args++;
 182                case 4:
 183                        if (!n--) break;
 184                        regs->di = *args++;
 185                case 5:
 186                        if (!n--) break;
 187                        regs->bp = *args++;
 188                case 6:
 189                        if (!n--) break;
 190                default:
 191                        BUG();
 192                        break;
 193                }
 194        else
 195# endif
 196                switch (i) {
 197                case 0:
 198                        if (!n--) break;
 199                        regs->di = *args++;
 200                case 1:
 201                        if (!n--) break;
 202                        regs->si = *args++;
 203                case 2:
 204                        if (!n--) break;
 205                        regs->dx = *args++;
 206                case 3:
 207                        if (!n--) break;
 208                        regs->r10 = *args++;
 209                case 4:
 210                        if (!n--) break;
 211                        regs->r8 = *args++;
 212                case 5:
 213                        if (!n--) break;
 214                        regs->r9 = *args++;
 215                case 6:
 216                        if (!n--) break;
 217                default:
 218                        BUG();
 219                        break;
 220                }
 221}
 222
 223static inline int syscall_get_arch(struct task_struct *task,
 224                                   struct pt_regs *regs)
 225{
 226#ifdef CONFIG_IA32_EMULATION
 227        /*
 228         * TS_COMPAT is set for 32-bit syscall entry and then
 229         * remains set until we return to user mode.
 230         *
 231         * TIF_IA32 tasks should always have TS_COMPAT set at
 232         * system call time.
 233         *
 234         * x32 tasks should be considered AUDIT_ARCH_X86_64.
 235         */
 236        if (task_thread_info(task)->status & TS_COMPAT)
 237                return AUDIT_ARCH_I386;
 238#endif
 239        /* Both x32 and x86_64 are considered "64-bit". */
 240        return AUDIT_ARCH_X86_64;
 241}
 242#endif  /* CONFIG_X86_32 */
 243
 244#endif  /* _ASM_X86_SYSCALL_H */
 245