1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Access to user system call parameters and results
4 *
5 *  Copyright IBM Corp. 2008
6 *  Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
7 */
8
9#ifndef _ASM_SYSCALL_H
10#define _ASM_SYSCALL_H	1
11
12#include <uapi/linux/audit.h>
13#include <linux/sched.h>
14#include <linux/err.h>
15#include <asm/ptrace.h>
16
17extern const sys_call_ptr_t sys_call_table[];
18extern const sys_call_ptr_t sys_call_table_emu[];
19
20static inline long syscall_get_nr(struct task_struct *task,
21				  struct pt_regs *regs)
22{
23	return test_pt_regs_flag(regs, PIF_SYSCALL) ?
24		(regs->int_code & 0xffff) : -1;
25}
26
27static inline void syscall_rollback(struct task_struct *task,
28				    struct pt_regs *regs)
29{
30	regs->gprs[2] = regs->orig_gpr2;
31}
32
33static inline long syscall_get_error(struct task_struct *task,
34				     struct pt_regs *regs)
35{
36	unsigned long error = regs->gprs[2];
37#ifdef CONFIG_COMPAT
38	if (test_tsk_thread_flag(task, TIF_31BIT)) {
39		/*
40		 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
41		 * and will match correctly in comparisons.
42		 */
43		error = (long)(int)error;
44	}
45#endif
46	return IS_ERR_VALUE(error) ? error : 0;
47}
48
49static inline long syscall_get_return_value(struct task_struct *task,
50					    struct pt_regs *regs)
51{
52	return regs->gprs[2];
53}
54
55static inline void syscall_set_return_value(struct task_struct *task,
56					    struct pt_regs *regs,
57					    int error, long val)
58{
59	set_pt_regs_flag(regs, PIF_SYSCALL_RET_SET);
60	regs->gprs[2] = error ? error : val;
61}
62
63static inline void syscall_get_arguments(struct task_struct *task,
64					 struct pt_regs *regs,
65					 unsigned long *args)
66{
67	unsigned long mask = -1UL;
68	unsigned int n = 6;
69
70#ifdef CONFIG_COMPAT
71	if (test_tsk_thread_flag(task, TIF_31BIT))
72		mask = 0xffffffff;
73#endif
74	while (n-- > 0)
75		if (n > 0)
76			args[n] = regs->gprs[2 + n] & mask;
77
78	args[0] = regs->orig_gpr2 & mask;
79}
80
81static inline int syscall_get_arch(struct task_struct *task)
82{
83#ifdef CONFIG_COMPAT
84	if (test_tsk_thread_flag(task, TIF_31BIT))
85		return AUDIT_ARCH_S390;
86#endif
87	return AUDIT_ARCH_S390X;
88}
89
90static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
91{
92	return false;
93}
94
95#define SYSCALL_FMT_0
96#define SYSCALL_FMT_1 , "0" (r2)
97#define SYSCALL_FMT_2 , "d" (r3) SYSCALL_FMT_1
98#define SYSCALL_FMT_3 , "d" (r4) SYSCALL_FMT_2
99#define SYSCALL_FMT_4 , "d" (r5) SYSCALL_FMT_3
100#define SYSCALL_FMT_5 , "d" (r6) SYSCALL_FMT_4
101#define SYSCALL_FMT_6 , "d" (r7) SYSCALL_FMT_5
102
103#define SYSCALL_PARM_0
104#define SYSCALL_PARM_1 , long arg1
105#define SYSCALL_PARM_2 SYSCALL_PARM_1, long arg2
106#define SYSCALL_PARM_3 SYSCALL_PARM_2, long arg3
107#define SYSCALL_PARM_4 SYSCALL_PARM_3, long arg4
108#define SYSCALL_PARM_5 SYSCALL_PARM_4, long arg5
109#define SYSCALL_PARM_6 SYSCALL_PARM_5, long arg6
110
111#define SYSCALL_REGS_0
112#define SYSCALL_REGS_1							\
113	register long r2 asm("2") = arg1
114#define SYSCALL_REGS_2							\
115	SYSCALL_REGS_1;							\
116	register long r3 asm("3") = arg2
117#define SYSCALL_REGS_3							\
118	SYSCALL_REGS_2;							\
119	register long r4 asm("4") = arg3
120#define SYSCALL_REGS_4							\
121	SYSCALL_REGS_3;							\
122	register long r5 asm("5") = arg4
123#define SYSCALL_REGS_5							\
124	SYSCALL_REGS_4;							\
125	register long r6 asm("6") = arg5
126#define SYSCALL_REGS_6							\
127	SYSCALL_REGS_5;							\
128	register long r7 asm("7") = arg6
129
130#define GENERATE_SYSCALL_FUNC(nr)					\
131static __always_inline							\
132long syscall##nr(unsigned long syscall SYSCALL_PARM_##nr)		\
133{									\
134	register unsigned long r1 asm ("1") = syscall;			\
135	register long rc asm ("2");					\
136	SYSCALL_REGS_##nr;						\
137									\
138	asm volatile (							\
139		"	svc	0\n"					\
140		: "=d" (rc)						\
141		: "d" (r1) SYSCALL_FMT_##nr				\
142		: "memory");						\
143	return rc;							\
144}
145
146GENERATE_SYSCALL_FUNC(0)
147GENERATE_SYSCALL_FUNC(1)
148GENERATE_SYSCALL_FUNC(2)
149GENERATE_SYSCALL_FUNC(3)
150GENERATE_SYSCALL_FUNC(4)
151GENERATE_SYSCALL_FUNC(5)
152GENERATE_SYSCALL_FUNC(6)
153
154#endif	/* _ASM_SYSCALL_H */
155