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

   1/* SPDX-License-Identifier: GPL-2.0-only */
   2/*
   3 * Access to user system call parameters and results
   4 *
   5 * Copyright (C) 2008-2009 Red Hat, Inc.  All rights reserved.
   6 *
   7 * See asm-generic/syscall.h for descriptions of what we must do here.
   8 */
   9
  10#ifndef _ASM_X86_SYSCALL_H
  11#define _ASM_X86_SYSCALL_H
  12
  13#include <uapi/linux/audit.h>
  14#include <linux/sched.h>
  15#include <linux/err.h>
  16#include <asm/thread_info.h>    /* for TS_COMPAT */
  17#include <asm/unistd.h>
  18
  19typedef long (*sys_call_ptr_t)(const struct pt_regs *);
  20extern const sys_call_ptr_t sys_call_table[];
  21
  22#if defined(CONFIG_X86_32)
  23#define ia32_sys_call_table sys_call_table
  24#endif
  25
  26#if defined(CONFIG_IA32_EMULATION)
  27extern const sys_call_ptr_t ia32_sys_call_table[];
  28#endif
  29
  30#ifdef CONFIG_X86_X32_ABI
  31extern const sys_call_ptr_t x32_sys_call_table[];
  32#endif
  33
  34/*
  35 * Only the low 32 bits of orig_ax are meaningful, so we return int.
  36 * This importantly ignores the high bits on 64-bit, so comparisons
  37 * sign-extend the low 32 bits.
  38 */
  39static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
  40{
  41        return regs->orig_ax;
  42}
  43
  44static inline void syscall_rollback(struct task_struct *task,
  45                                    struct pt_regs *regs)
  46{
  47        regs->ax = regs->orig_ax;
  48}
  49
  50static inline long syscall_get_error(struct task_struct *task,
  51                                     struct pt_regs *regs)
  52{
  53        unsigned long error = regs->ax;
  54#ifdef CONFIG_IA32_EMULATION
  55        /*
  56         * TS_COMPAT is set for 32-bit syscall entries and then
  57         * remains set until we return to user mode.
  58         */
  59        if (task->thread_info.status & (TS_COMPAT|TS_I386_REGS_POKED))
  60                /*
  61                 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
  62                 * and will match correctly in comparisons.
  63                 */
  64                error = (long) (int) error;
  65#endif
  66        return IS_ERR_VALUE(error) ? error : 0;
  67}
  68
  69static inline long syscall_get_return_value(struct task_struct *task,
  70                                            struct pt_regs *regs)
  71{
  72        return regs->ax;
  73}
  74
  75static inline void syscall_set_return_value(struct task_struct *task,
  76                                            struct pt_regs *regs,
  77                                            int error, long val)
  78{
  79        regs->ax = (long) error ?: val;
  80}
  81
  82#ifdef CONFIG_X86_32
  83
  84static inline void syscall_get_arguments(struct task_struct *task,
  85                                         struct pt_regs *regs,
  86                                         unsigned long *args)
  87{
  88        memcpy(args, &regs->bx, 6 * sizeof(args[0]));
  89}
  90
  91static inline void syscall_set_arguments(struct task_struct *task,
  92                                         struct pt_regs *regs,
  93                                         unsigned int i, unsigned int n,
  94                                         const unsigned long *args)
  95{
  96        BUG_ON(i + n > 6);
  97        memcpy(&regs->bx + i, args, n * sizeof(args[0]));
  98}
  99
 100static inline int syscall_get_arch(struct task_struct *task)
 101{
 102        return AUDIT_ARCH_I386;
 103}
 104
 105#else    /* CONFIG_X86_64 */
 106
 107static inline void syscall_get_arguments(struct task_struct *task,
 108                                         struct pt_regs *regs,
 109                                         unsigned long *args)
 110{
 111# ifdef CONFIG_IA32_EMULATION
 112        if (task->thread_info.status & TS_COMPAT) {
 113                *args++ = regs->bx;
 114                *args++ = regs->cx;
 115                *args++ = regs->dx;
 116                *args++ = regs->si;
 117                *args++ = regs->di;
 118                *args   = regs->bp;
 119        } else
 120# endif
 121        {
 122                *args++ = regs->di;
 123                *args++ = regs->si;
 124                *args++ = regs->dx;
 125                *args++ = regs->r10;
 126                *args++ = regs->r8;
 127                *args   = regs->r9;
 128        }
 129}
 130
 131static inline void syscall_set_arguments(struct task_struct *task,
 132                                         struct pt_regs *regs,
 133                                         const unsigned long *args)
 134{
 135# ifdef CONFIG_IA32_EMULATION
 136        if (task->thread_info.status & TS_COMPAT) {
 137                regs->bx = *args++;
 138                regs->cx = *args++;
 139                regs->dx = *args++;
 140                regs->si = *args++;
 141                regs->di = *args++;
 142                regs->bp = *args;
 143        } else
 144# endif
 145        {
 146                regs->di = *args++;
 147                regs->si = *args++;
 148                regs->dx = *args++;
 149                regs->r10 = *args++;
 150                regs->r8 = *args++;
 151                regs->r9 = *args;
 152        }
 153}
 154
 155static inline int syscall_get_arch(struct task_struct *task)
 156{
 157        /* x32 tasks should be considered AUDIT_ARCH_X86_64. */
 158        return (IS_ENABLED(CONFIG_IA32_EMULATION) &&
 159                task->thread_info.status & TS_COMPAT)
 160                ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
 161}
 162
 163void do_syscall_64(unsigned long nr, struct pt_regs *regs);
 164void do_int80_syscall_32(struct pt_regs *regs);
 165long do_fast_syscall_32(struct pt_regs *regs);
 166
 167#endif  /* CONFIG_X86_32 */
 168
 169#endif  /* _ASM_X86_SYSCALL_H */
 170