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 #else
25 /*
26  * These may not exist, but still put the prototypes in so we
27  * can use IS_ENABLED().
28  */
29 extern const sys_call_ptr_t ia32_sys_call_table[];
30 extern const sys_call_ptr_t x32_sys_call_table[];
31 #endif
32 
33 /*
34  * Only the low 32 bits of orig_ax are meaningful, so we return int.
35  * This importantly ignores the high bits on 64-bit, so comparisons
36  * sign-extend the low 32 bits.
37  */
syscall_get_nr(struct task_struct * task,struct pt_regs * regs)38 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
39 {
40 	return regs->orig_ax;
41 }
42 
syscall_rollback(struct task_struct * task,struct pt_regs * regs)43 static inline void syscall_rollback(struct task_struct *task,
44 				    struct pt_regs *regs)
45 {
46 	regs->ax = regs->orig_ax;
47 }
48 
syscall_get_error(struct task_struct * task,struct pt_regs * regs)49 static inline long syscall_get_error(struct task_struct *task,
50 				     struct pt_regs *regs)
51 {
52 	unsigned long error = regs->ax;
53 #ifdef CONFIG_IA32_EMULATION
54 	/*
55 	 * TS_COMPAT is set for 32-bit syscall entries and then
56 	 * remains set until we return to user mode.
57 	 */
58 	if (task->thread_info.status & (TS_COMPAT|TS_I386_REGS_POKED))
59 		/*
60 		 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
61 		 * and will match correctly in comparisons.
62 		 */
63 		error = (long) (int) error;
64 #endif
65 	return IS_ERR_VALUE(error) ? error : 0;
66 }
67 
syscall_get_return_value(struct task_struct * task,struct pt_regs * regs)68 static inline long syscall_get_return_value(struct task_struct *task,
69 					    struct pt_regs *regs)
70 {
71 	return regs->ax;
72 }
73 
syscall_set_return_value(struct task_struct * task,struct pt_regs * regs,int error,long val)74 static inline void syscall_set_return_value(struct task_struct *task,
75 					    struct pt_regs *regs,
76 					    int error, long val)
77 {
78 	regs->ax = (long) error ?: val;
79 }
80 
81 #ifdef CONFIG_X86_32
82 
syscall_get_arguments(struct task_struct * task,struct pt_regs * regs,unsigned long * args)83 static inline void syscall_get_arguments(struct task_struct *task,
84 					 struct pt_regs *regs,
85 					 unsigned long *args)
86 {
87 	memcpy(args, &regs->bx, 6 * sizeof(args[0]));
88 }
89 
syscall_get_arch(struct task_struct * task)90 static inline int syscall_get_arch(struct task_struct *task)
91 {
92 	return AUDIT_ARCH_I386;
93 }
94 
95 #else	 /* CONFIG_X86_64 */
96 
syscall_get_arguments(struct task_struct * task,struct pt_regs * regs,unsigned long * args)97 static inline void syscall_get_arguments(struct task_struct *task,
98 					 struct pt_regs *regs,
99 					 unsigned long *args)
100 {
101 # ifdef CONFIG_IA32_EMULATION
102 	if (task->thread_info.status & TS_COMPAT) {
103 		*args++ = regs->bx;
104 		*args++ = regs->cx;
105 		*args++ = regs->dx;
106 		*args++ = regs->si;
107 		*args++ = regs->di;
108 		*args   = regs->bp;
109 	} else
110 # endif
111 	{
112 		*args++ = regs->di;
113 		*args++ = regs->si;
114 		*args++ = regs->dx;
115 		*args++ = regs->r10;
116 		*args++ = regs->r8;
117 		*args   = regs->r9;
118 	}
119 }
120 
syscall_get_arch(struct task_struct * task)121 static inline int syscall_get_arch(struct task_struct *task)
122 {
123 	/* x32 tasks should be considered AUDIT_ARCH_X86_64. */
124 	return (IS_ENABLED(CONFIG_IA32_EMULATION) &&
125 		task->thread_info.status & TS_COMPAT)
126 		? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
127 }
128 
129 void do_syscall_64(struct pt_regs *regs, int nr);
130 void do_int80_syscall_32(struct pt_regs *regs);
131 long do_fast_syscall_32(struct pt_regs *regs);
132 
133 #endif	/* CONFIG_X86_32 */
134 
135 #endif	/* _ASM_X86_SYSCALL_H */
136