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 unsigned long sys_call_table[];
18extern const unsigned long 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	regs->gprs[2] = error ? error : val;
60}
61
62static inline void syscall_get_arguments(struct task_struct *task,
63					 struct pt_regs *regs,
64					 unsigned long *args)
65{
66	unsigned long mask = -1UL;
67	unsigned int n = 6;
68
69#ifdef CONFIG_COMPAT
70	if (test_tsk_thread_flag(task, TIF_31BIT))
71		mask = 0xffffffff;
72#endif
73	while (n-- > 0)
74		if (n > 0)
75			args[n] = regs->gprs[2 + n] & mask;
76
77	args[0] = regs->orig_gpr2 & mask;
78}
79
80static inline void syscall_set_arguments(struct task_struct *task,
81					 struct pt_regs *regs,
82					 const unsigned long *args)
83{
84	unsigned int n = 6;
85
86	while (n-- > 0)
87		if (n > 0)
88			regs->gprs[2 + n] = args[n];
89	regs->orig_gpr2 = args[0];
90}
91
92static inline int syscall_get_arch(struct task_struct *task)
93{
94#ifdef CONFIG_COMPAT
95	if (test_tsk_thread_flag(task, TIF_31BIT))
96		return AUDIT_ARCH_S390;
97#endif
98	return AUDIT_ARCH_S390X;
99}
100#endif	/* _ASM_SYSCALL_H */
101