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#else
  25/*
  26 * These may not exist, but still put the prototypes in so we
  27 * can use IS_ENABLED().
  28 */
  29extern const sys_call_ptr_t ia32_sys_call_table[];
  30extern const sys_call_ptr_t x32_sys_call_table[];
  31#endif
  32
  33/*
  34 * Only the low 32 bits of orig_ax are meaningful, so we return int.
  35 * This importantly ignores the high bits on 64-bit, so comparisons
  36 * sign-extend the low 32 bits.
  37 */
  38static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
  39{
  40        return regs->orig_ax;
  41}
  42
  43static inline void syscall_rollback(struct task_struct *task,
  44                                    struct pt_regs *regs)
  45{
  46        regs->ax = regs->orig_ax;
  47}
  48
  49static inline long syscall_get_error(struct task_struct *task,
  50                                     struct pt_regs *regs)
  51{
  52        unsigned long error = regs->ax;
  53#ifdef CONFIG_IA32_EMULATION
  54        /*
  55         * TS_COMPAT is set for 32-bit syscall entries and then
  56         * remains set until we return to user mode.
  57         */
  58        if (task->thread_info.status & (TS_COMPAT|TS_I386_REGS_POKED))
  59                /*
  60                 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
  61                 * and will match correctly in comparisons.
  62                 */
  63                error = (long) (int) error;
  64#endif
  65        return IS_ERR_VALUE(error) ? error : 0;
  66}
  67
  68static inline long syscall_get_return_value(struct task_struct *task,
  69                                            struct pt_regs *regs)
  70{
  71        return regs->ax;
  72}
  73
  74static inline void syscall_set_return_value(struct task_struct *task,
  75                                            struct pt_regs *regs,
  76                                            int error, long val)
  77{
  78        regs->ax = (long) error ?: val;
  79}
  80
  81#ifdef CONFIG_X86_32
  82
  83static inline void syscall_get_arguments(struct task_struct *task,
  84                                         struct pt_regs *regs,
  85                                         unsigned long *args)
  86{
  87        memcpy(args, &regs->bx, 6 * sizeof(args[0]));
  88}
  89
  90static inline void syscall_set_arguments(struct task_struct *task,
  91                                         struct pt_regs *regs,
  92                                         unsigned int i, unsigned int n,
  93                                         const unsigned long *args)
  94{
  95        BUG_ON(i + n > 6);
  96        memcpy(&regs->bx + i, args, n * sizeof(args[0]));
  97}
  98
  99static inline int syscall_get_arch(struct task_struct *task)
 100{
 101        return AUDIT_ARCH_I386;
 102}
 103
 104#else    /* CONFIG_X86_64 */
 105
 106static inline void syscall_get_arguments(struct task_struct *task,
 107                                         struct pt_regs *regs,
 108                                         unsigned long *args)
 109{
 110# ifdef CONFIG_IA32_EMULATION
 111        if (task->thread_info.status & TS_COMPAT) {
 112                *args++ = regs->bx;
 113                *args++ = regs->cx;
 114                *args++ = regs->dx;
 115                *args++ = regs->si;
 116                *args++ = regs->di;
 117                *args   = regs->bp;
 118        } else
 119# endif
 120        {
 121                *args++ = regs->di;
 122                *args++ = regs->si;
 123                *args++ = regs->dx;
 124                *args++ = regs->r10;
 125                *args++ = regs->r8;
 126                *args   = regs->r9;
 127        }
 128}
 129
 130static inline void syscall_set_arguments(struct task_struct *task,
 131                                         struct pt_regs *regs,
 132                                         const unsigned long *args)
 133{
 134# ifdef CONFIG_IA32_EMULATION
 135        if (task->thread_info.status & TS_COMPAT) {
 136                regs->bx = *args++;
 137                regs->cx = *args++;
 138                regs->dx = *args++;
 139                regs->si = *args++;
 140                regs->di = *args++;
 141                regs->bp = *args;
 142        } else
 143# endif
 144        {
 145                regs->di = *args++;
 146                regs->si = *args++;
 147                regs->dx = *args++;
 148                regs->r10 = *args++;
 149                regs->r8 = *args++;
 150                regs->r9 = *args;
 151        }
 152}
 153
 154static inline int syscall_get_arch(struct task_struct *task)
 155{
 156        /* x32 tasks should be considered AUDIT_ARCH_X86_64. */
 157        return (IS_ENABLED(CONFIG_IA32_EMULATION) &&
 158                task->thread_info.status & TS_COMPAT)
 159                ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
 160}
 161
 162void do_syscall_64(struct pt_regs *regs, int nr);
 163void do_int80_syscall_32(struct pt_regs *regs);
 164long do_fast_syscall_32(struct pt_regs *regs);
 165
 166#endif  /* CONFIG_X86_32 */
 167
 168#endif  /* _ASM_X86_SYSCALL_H */
 169