Linux kernel mirror (for testing)
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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
19/* This is used purely for kernel/trace/trace_syscalls.c */
20typedef long (*sys_call_ptr_t)(const struct pt_regs *);
21extern const sys_call_ptr_t sys_call_table[];
22
23/*
24 * These may not exist, but still put the prototypes in so we
25 * can use IS_ENABLED().
26 */
27extern long ia32_sys_call(const struct pt_regs *, unsigned int nr);
28extern long x32_sys_call(const struct pt_regs *, unsigned int nr);
29extern long x64_sys_call(const struct pt_regs *, unsigned int nr);
30
31/*
32 * Only the low 32 bits of orig_ax are meaningful, so we return int.
33 * This importantly ignores the high bits on 64-bit, so comparisons
34 * sign-extend the low 32 bits.
35 */
36static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
37{
38 return regs->orig_ax;
39}
40
41static inline void syscall_rollback(struct task_struct *task,
42 struct pt_regs *regs)
43{
44 regs->ax = regs->orig_ax;
45}
46
47static inline long syscall_get_error(struct task_struct *task,
48 struct pt_regs *regs)
49{
50 unsigned long error = regs->ax;
51#ifdef CONFIG_IA32_EMULATION
52 /*
53 * TS_COMPAT is set for 32-bit syscall entries and then
54 * remains set until we return to user mode.
55 */
56 if (task->thread_info.status & (TS_COMPAT|TS_I386_REGS_POKED))
57 /*
58 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
59 * and will match correctly in comparisons.
60 */
61 error = (long) (int) error;
62#endif
63 return IS_ERR_VALUE(error) ? error : 0;
64}
65
66static inline long syscall_get_return_value(struct task_struct *task,
67 struct pt_regs *regs)
68{
69 return regs->ax;
70}
71
72static inline void syscall_set_return_value(struct task_struct *task,
73 struct pt_regs *regs,
74 int error, long val)
75{
76 regs->ax = (long) error ?: val;
77}
78
79#ifdef CONFIG_X86_32
80
81static inline void syscall_get_arguments(struct task_struct *task,
82 struct pt_regs *regs,
83 unsigned long *args)
84{
85 args[0] = regs->bx;
86 args[1] = regs->cx;
87 args[2] = regs->dx;
88 args[3] = regs->si;
89 args[4] = regs->di;
90 args[5] = regs->bp;
91}
92
93static inline int syscall_get_arch(struct task_struct *task)
94{
95 return AUDIT_ARCH_I386;
96}
97
98#else /* CONFIG_X86_64 */
99
100static inline void syscall_get_arguments(struct task_struct *task,
101 struct pt_regs *regs,
102 unsigned long *args)
103{
104# ifdef CONFIG_IA32_EMULATION
105 if (task->thread_info.status & TS_COMPAT) {
106 *args++ = regs->bx;
107 *args++ = regs->cx;
108 *args++ = regs->dx;
109 *args++ = regs->si;
110 *args++ = regs->di;
111 *args = regs->bp;
112 } else
113# endif
114 {
115 *args++ = regs->di;
116 *args++ = regs->si;
117 *args++ = regs->dx;
118 *args++ = regs->r10;
119 *args++ = regs->r8;
120 *args = regs->r9;
121 }
122}
123
124static inline int syscall_get_arch(struct task_struct *task)
125{
126 /* x32 tasks should be considered AUDIT_ARCH_X86_64. */
127 return (IS_ENABLED(CONFIG_IA32_EMULATION) &&
128 task->thread_info.status & TS_COMPAT)
129 ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
130}
131
132bool do_syscall_64(struct pt_regs *regs, int nr);
133void do_int80_emulation(struct pt_regs *regs);
134
135#endif /* CONFIG_X86_32 */
136
137void do_int80_syscall_32(struct pt_regs *regs);
138bool do_fast_syscall_32(struct pt_regs *regs);
139bool do_SYSENTER_32(struct pt_regs *regs);
140
141#endif /* _ASM_X86_SYSCALL_H */