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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/asm-offsets.h> /* For NR_syscalls */
17#include <asm/thread_info.h> /* for TS_COMPAT */
18#include <asm/unistd.h>
19
20#ifdef CONFIG_X86_64
21typedef asmlinkage long (*sys_call_ptr_t)(const struct pt_regs *);
22#else
23typedef asmlinkage long (*sys_call_ptr_t)(unsigned long, unsigned long,
24 unsigned long, unsigned long,
25 unsigned long, unsigned long);
26#endif /* CONFIG_X86_64 */
27extern const sys_call_ptr_t sys_call_table[];
28
29#if defined(CONFIG_X86_32)
30#define ia32_sys_call_table sys_call_table
31#define __NR_syscall_compat_max __NR_syscall_max
32#define IA32_NR_syscalls NR_syscalls
33#endif
34
35#if defined(CONFIG_IA32_EMULATION)
36extern const sys_call_ptr_t ia32_sys_call_table[];
37#endif
38
39#ifdef CONFIG_X86_X32_ABI
40extern const sys_call_ptr_t x32_sys_call_table[];
41#endif
42
43/*
44 * Only the low 32 bits of orig_ax are meaningful, so we return int.
45 * This importantly ignores the high bits on 64-bit, so comparisons
46 * sign-extend the low 32 bits.
47 */
48static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
49{
50 return regs->orig_ax;
51}
52
53static inline void syscall_rollback(struct task_struct *task,
54 struct pt_regs *regs)
55{
56 regs->ax = regs->orig_ax;
57}
58
59static inline long syscall_get_error(struct task_struct *task,
60 struct pt_regs *regs)
61{
62 unsigned long error = regs->ax;
63#ifdef CONFIG_IA32_EMULATION
64 /*
65 * TS_COMPAT is set for 32-bit syscall entries and then
66 * remains set until we return to user mode.
67 */
68 if (task->thread_info.status & (TS_COMPAT|TS_I386_REGS_POKED))
69 /*
70 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
71 * and will match correctly in comparisons.
72 */
73 error = (long) (int) error;
74#endif
75 return IS_ERR_VALUE(error) ? error : 0;
76}
77
78static inline long syscall_get_return_value(struct task_struct *task,
79 struct pt_regs *regs)
80{
81 return regs->ax;
82}
83
84static inline void syscall_set_return_value(struct task_struct *task,
85 struct pt_regs *regs,
86 int error, long val)
87{
88 regs->ax = (long) error ?: val;
89}
90
91#ifdef CONFIG_X86_32
92
93static inline void syscall_get_arguments(struct task_struct *task,
94 struct pt_regs *regs,
95 unsigned long *args)
96{
97 memcpy(args, ®s->bx, 6 * sizeof(args[0]));
98}
99
100static inline void syscall_set_arguments(struct task_struct *task,
101 struct pt_regs *regs,
102 unsigned int i, unsigned int n,
103 const unsigned long *args)
104{
105 BUG_ON(i + n > 6);
106 memcpy(®s->bx + i, args, n * sizeof(args[0]));
107}
108
109static inline int syscall_get_arch(struct task_struct *task)
110{
111 return AUDIT_ARCH_I386;
112}
113
114#else /* CONFIG_X86_64 */
115
116static inline void syscall_get_arguments(struct task_struct *task,
117 struct pt_regs *regs,
118 unsigned long *args)
119{
120# ifdef CONFIG_IA32_EMULATION
121 if (task->thread_info.status & TS_COMPAT) {
122 *args++ = regs->bx;
123 *args++ = regs->cx;
124 *args++ = regs->dx;
125 *args++ = regs->si;
126 *args++ = regs->di;
127 *args = regs->bp;
128 } else
129# endif
130 {
131 *args++ = regs->di;
132 *args++ = regs->si;
133 *args++ = regs->dx;
134 *args++ = regs->r10;
135 *args++ = regs->r8;
136 *args = regs->r9;
137 }
138}
139
140static inline void syscall_set_arguments(struct task_struct *task,
141 struct pt_regs *regs,
142 const unsigned long *args)
143{
144# ifdef CONFIG_IA32_EMULATION
145 if (task->thread_info.status & TS_COMPAT) {
146 regs->bx = *args++;
147 regs->cx = *args++;
148 regs->dx = *args++;
149 regs->si = *args++;
150 regs->di = *args++;
151 regs->bp = *args;
152 } else
153# endif
154 {
155 regs->di = *args++;
156 regs->si = *args++;
157 regs->dx = *args++;
158 regs->r10 = *args++;
159 regs->r8 = *args++;
160 regs->r9 = *args;
161 }
162}
163
164static inline int syscall_get_arch(struct task_struct *task)
165{
166 /* x32 tasks should be considered AUDIT_ARCH_X86_64. */
167 return (IS_ENABLED(CONFIG_IA32_EMULATION) &&
168 task->thread_info.status & TS_COMPAT)
169 ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
170}
171#endif /* CONFIG_X86_32 */
172
173#endif /* _ASM_X86_SYSCALL_H */