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 typedef long (*sys_call_ptr_t)(const struct pt_regs *);
20 extern 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)
27 extern const sys_call_ptr_t ia32_sys_call_table[];
28 #endif
29
30 #ifdef CONFIG_X86_X32_ABI
31 extern 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 */
syscall_get_nr(struct task_struct * task,struct pt_regs * regs)39 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
40 {
41 return regs->orig_ax;
42 }
43
syscall_rollback(struct task_struct * task,struct pt_regs * regs)44 static inline void syscall_rollback(struct task_struct *task,
45 struct pt_regs *regs)
46 {
47 regs->ax = regs->orig_ax;
48 }
49
syscall_get_error(struct task_struct * task,struct pt_regs * regs)50 static 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
syscall_get_return_value(struct task_struct * task,struct pt_regs * regs)69 static inline long syscall_get_return_value(struct task_struct *task,
70 struct pt_regs *regs)
71 {
72 return regs->ax;
73 }
74
syscall_set_return_value(struct task_struct * task,struct pt_regs * regs,int error,long val)75 static 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
syscall_get_arguments(struct task_struct * task,struct pt_regs * regs,unsigned long * args)84 static inline void syscall_get_arguments(struct task_struct *task,
85 struct pt_regs *regs,
86 unsigned long *args)
87 {
88 memcpy(args, ®s->bx, 6 * sizeof(args[0]));
89 }
90
syscall_set_arguments(struct task_struct * task,struct pt_regs * regs,unsigned int i,unsigned int n,const unsigned long * args)91 static 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(®s->bx + i, args, n * sizeof(args[0]));
98 }
99
syscall_get_arch(struct task_struct * task)100 static inline int syscall_get_arch(struct task_struct *task)
101 {
102 return AUDIT_ARCH_I386;
103 }
104
105 #else /* CONFIG_X86_64 */
106
syscall_get_arguments(struct task_struct * task,struct pt_regs * regs,unsigned long * args)107 static 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
syscall_set_arguments(struct task_struct * task,struct pt_regs * regs,const unsigned long * args)131 static 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
syscall_get_arch(struct task_struct * task)155 static 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
163 void do_syscall_64(unsigned long nr, struct pt_regs *regs);
164 void do_int80_syscall_32(struct pt_regs *regs);
165 long do_fast_syscall_32(struct pt_regs *regs);
166
167 #endif /* CONFIG_X86_32 */
168
169 #endif /* _ASM_X86_SYSCALL_H */
170