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