1/*
2 * Access to user system call parameters and results
3 *
4 * Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved.
5 *
6 * This copyrighted material is made available to anyone wishing to use,
7 * modify, copy, or redistribute it subject to the terms and conditions
8 * of the GNU General Public License v.2.
9 *
10 * See asm-generic/syscall.h for descriptions of what we must do here.
11 */
12
13#ifndef _ASM_X86_SYSCALL_H
14#define _ASM_X86_SYSCALL_H
15
16#include <uapi/linux/audit.h>
17#include <linux/sched.h>
18#include <linux/err.h>
19#include <asm/asm-offsets.h> /* For NR_syscalls */
20#include <asm/thread_info.h> /* for TS_COMPAT */
21#include <asm/unistd.h>
22
23#ifdef CONFIG_X86_64
24typedef asmlinkage long (*sys_call_ptr_t)(const struct pt_regs *);
25#else
26typedef asmlinkage long (*sys_call_ptr_t)(unsigned long, unsigned long,
27 unsigned long, unsigned long,
28 unsigned long, unsigned long);
29#endif /* CONFIG_X86_64 */
30extern const sys_call_ptr_t sys_call_table[];
31
32#if defined(CONFIG_X86_32)
33#define ia32_sys_call_table sys_call_table
34#define __NR_syscall_compat_max __NR_syscall_max
35#define IA32_NR_syscalls NR_syscalls
36#endif
37
38#if defined(CONFIG_IA32_EMULATION)
39extern const sys_call_ptr_t ia32_sys_call_table[];
40#endif
41
42/*
43 * Only the low 32 bits of orig_ax are meaningful, so we return int.
44 * This importantly ignores the high bits on 64-bit, so comparisons
45 * sign-extend the low 32 bits.
46 */
47static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
48{
49 return regs->orig_ax;
50}
51
52static inline void syscall_rollback(struct task_struct *task,
53 struct pt_regs *regs)
54{
55 regs->ax = regs->orig_ax;
56}
57
58static inline long syscall_get_error(struct task_struct *task,
59 struct pt_regs *regs)
60{
61 unsigned long error = regs->ax;
62#ifdef CONFIG_IA32_EMULATION
63 /*
64 * TS_COMPAT is set for 32-bit syscall entries and then
65 * remains set until we return to user mode.
66 */
67 if (task->thread_info.status & (TS_COMPAT|TS_I386_REGS_POKED))
68 /*
69 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
70 * and will match correctly in comparisons.
71 */
72 error = (long) (int) error;
73#endif
74 return IS_ERR_VALUE(error) ? error : 0;
75}
76
77static inline long syscall_get_return_value(struct task_struct *task,
78 struct pt_regs *regs)
79{
80 return regs->ax;
81}
82
83static inline void syscall_set_return_value(struct task_struct *task,
84 struct pt_regs *regs,
85 int error, long val)
86{
87 regs->ax = (long) error ?: val;
88}
89
90#ifdef CONFIG_X86_32
91
92static inline void syscall_get_arguments(struct task_struct *task,
93 struct pt_regs *regs,
94 unsigned int i, unsigned int n,
95 unsigned long *args)
96{
97 BUG_ON(i + n > 6);
98 memcpy(args, &regs->bx + i, n * sizeof(args[0]));
99}
100
101static inline void syscall_set_arguments(struct task_struct *task,
102 struct pt_regs *regs,
103 unsigned int i, unsigned int n,
104 const unsigned long *args)
105{
106 BUG_ON(i + n > 6);
107 memcpy(&regs->bx + i, args, n * sizeof(args[0]));
108}
109
110static inline int syscall_get_arch(void)
111{
112 return AUDIT_ARCH_I386;
113}
114
115#else /* CONFIG_X86_64 */
116
117static inline void syscall_get_arguments(struct task_struct *task,
118 struct pt_regs *regs,
119 unsigned int i, unsigned int n,
120 unsigned long *args)
121{
122# ifdef CONFIG_IA32_EMULATION
123 if (task->thread_info.status & TS_COMPAT)
124 switch (i) {
125 case 0:
126 if (!n--) break;
127 *args++ = regs->bx;
128 case 1:
129 if (!n--) break;
130 *args++ = regs->cx;
131 case 2:
132 if (!n--) break;
133 *args++ = regs->dx;
134 case 3:
135 if (!n--) break;
136 *args++ = regs->si;
137 case 4:
138 if (!n--) break;
139 *args++ = regs->di;
140 case 5:
141 if (!n--) break;
142 *args++ = regs->bp;
143 case 6:
144 if (!n--) break;
145 default:
146 BUG();
147 break;
148 }
149 else
150# endif
151 switch (i) {
152 case 0:
153 if (!n--) break;
154 *args++ = regs->di;
155 case 1:
156 if (!n--) break;
157 *args++ = regs->si;
158 case 2:
159 if (!n--) break;
160 *args++ = regs->dx;
161 case 3:
162 if (!n--) break;
163 *args++ = regs->r10;
164 case 4:
165 if (!n--) break;
166 *args++ = regs->r8;
167 case 5:
168 if (!n--) break;
169 *args++ = regs->r9;
170 case 6:
171 if (!n--) break;
172 default:
173 BUG();
174 break;
175 }
176}
177
178static inline void syscall_set_arguments(struct task_struct *task,
179 struct pt_regs *regs,
180 unsigned int i, unsigned int n,
181 const unsigned long *args)
182{
183# ifdef CONFIG_IA32_EMULATION
184 if (task->thread_info.status & TS_COMPAT)
185 switch (i) {
186 case 0:
187 if (!n--) break;
188 regs->bx = *args++;
189 case 1:
190 if (!n--) break;
191 regs->cx = *args++;
192 case 2:
193 if (!n--) break;
194 regs->dx = *args++;
195 case 3:
196 if (!n--) break;
197 regs->si = *args++;
198 case 4:
199 if (!n--) break;
200 regs->di = *args++;
201 case 5:
202 if (!n--) break;
203 regs->bp = *args++;
204 case 6:
205 if (!n--) break;
206 default:
207 BUG();
208 break;
209 }
210 else
211# endif
212 switch (i) {
213 case 0:
214 if (!n--) break;
215 regs->di = *args++;
216 case 1:
217 if (!n--) break;
218 regs->si = *args++;
219 case 2:
220 if (!n--) break;
221 regs->dx = *args++;
222 case 3:
223 if (!n--) break;
224 regs->r10 = *args++;
225 case 4:
226 if (!n--) break;
227 regs->r8 = *args++;
228 case 5:
229 if (!n--) break;
230 regs->r9 = *args++;
231 case 6:
232 if (!n--) break;
233 default:
234 BUG();
235 break;
236 }
237}
238
239static inline int syscall_get_arch(void)
240{
241 /* x32 tasks should be considered AUDIT_ARCH_X86_64. */
242 return in_ia32_syscall() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
243}
244#endif /* CONFIG_X86_32 */
245
246#endif /* _ASM_X86_SYSCALL_H */
247