syscall.h

  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[];
 18
 19static inline long syscall_get_nr(struct task_struct *task,
 20				  struct pt_regs *regs)
 21{
 22	return test_pt_regs_flag(regs, PIF_SYSCALL) ?
 23		(regs->int_code & 0xffff) : -1;
 24}
 25
 26static inline void syscall_set_nr(struct task_struct *task,
 27				  struct pt_regs *regs,
 28				  int nr)
 29{
 30	/*
 31	 * Unlike syscall_get_nr(), syscall_set_nr() can be called only when
 32	 * the target task is stopped for tracing on entering syscall, so
 33	 * there is no need to have the same check syscall_get_nr() has.
 34	 */
 35	regs->int_code = (regs->int_code & ~0xffff) | (nr & 0xffff);
 36}
 37
 38static inline void syscall_rollback(struct task_struct *task,
 39				    struct pt_regs *regs)
 40{
 41	regs->gprs[2] = regs->orig_gpr2;
 42}
 43
 44static inline long syscall_get_error(struct task_struct *task,
 45				     struct pt_regs *regs)
 46{
 47	unsigned long error = regs->gprs[2];
 48
 49	return IS_ERR_VALUE(error) ? error : 0;
 50}
 51
 52static inline long syscall_get_return_value(struct task_struct *task,
 53					    struct pt_regs *regs)
 54{
 55	return regs->gprs[2];
 56}
 57
 58static inline void syscall_set_return_value(struct task_struct *task,
 59					    struct pt_regs *regs,
 60					    int error, long val)
 61{
 62	set_pt_regs_flag(regs, PIF_SYSCALL_RET_SET);
 63	regs->gprs[2] = error ? error : val;
 64}
 65
 66static inline void syscall_get_arguments(struct task_struct *task,
 67					 struct pt_regs *regs,
 68					 unsigned long *args)
 69{
 70	unsigned long mask = -1UL;
 71
 72	for (int i = 1; i < 6; i++)
 73		args[i] = regs->gprs[2 + i] & mask;
 74
 75	args[0] = regs->orig_gpr2 & mask;
 76}
 77
 78static inline void syscall_set_arguments(struct task_struct *task,
 79					 struct pt_regs *regs,
 80					 const unsigned long *args)
 81{
 82	regs->orig_gpr2 = args[0];
 83	for (int n = 1; n < 6; n++)
 84		regs->gprs[2 + n] = args[n];
 85}
 86
 87static inline int syscall_get_arch(struct task_struct *task)
 88{
 89	return AUDIT_ARCH_S390X;
 90}
 91
 92static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
 93{
 94	return false;
 95}
 96
 97#define SYSCALL_FMT_0
 98#define SYSCALL_FMT_1 , "0" (r2)
 99#define SYSCALL_FMT_2 , "d" (r3) SYSCALL_FMT_1
100#define SYSCALL_FMT_3 , "d" (r4) SYSCALL_FMT_2
101#define SYSCALL_FMT_4 , "d" (r5) SYSCALL_FMT_3
102#define SYSCALL_FMT_5 , "d" (r6) SYSCALL_FMT_4
103#define SYSCALL_FMT_6 , "d" (r7) SYSCALL_FMT_5
104
105#define SYSCALL_PARM_0
106#define SYSCALL_PARM_1 , long arg1
107#define SYSCALL_PARM_2 SYSCALL_PARM_1, long arg2
108#define SYSCALL_PARM_3 SYSCALL_PARM_2, long arg3
109#define SYSCALL_PARM_4 SYSCALL_PARM_3, long arg4
110#define SYSCALL_PARM_5 SYSCALL_PARM_4, long arg5
111#define SYSCALL_PARM_6 SYSCALL_PARM_5, long arg6
112
113#define SYSCALL_REGS_0
114#define SYSCALL_REGS_1							\
115	register long r2 asm("2") = arg1
116#define SYSCALL_REGS_2							\
117	SYSCALL_REGS_1;							\
118	register long r3 asm("3") = arg2
119#define SYSCALL_REGS_3							\
120	SYSCALL_REGS_2;							\
121	register long r4 asm("4") = arg3
122#define SYSCALL_REGS_4							\
123	SYSCALL_REGS_3;							\
124	register long r5 asm("5") = arg4
125#define SYSCALL_REGS_5							\
126	SYSCALL_REGS_4;							\
127	register long r6 asm("6") = arg5
128#define SYSCALL_REGS_6							\
129	SYSCALL_REGS_5;							\
130	register long r7 asm("7") = arg6
131
132#define GENERATE_SYSCALL_FUNC(nr)					\
133static __always_inline							\
134long syscall##nr(unsigned long syscall SYSCALL_PARM_##nr)		\
135{									\
136	register unsigned long r1 asm ("1") = syscall;			\
137	register long rc asm ("2");					\
138	SYSCALL_REGS_##nr;						\
139									\
140	asm volatile (							\
141		"	svc	0"					\
142		: "=d" (rc)						\
143		: "d" (r1) SYSCALL_FMT_##nr				\
144		: "memory");						\
145	return rc;							\
146}
147
148GENERATE_SYSCALL_FUNC(0)
149GENERATE_SYSCALL_FUNC(1)
150GENERATE_SYSCALL_FUNC(2)
151GENERATE_SYSCALL_FUNC(3)
152GENERATE_SYSCALL_FUNC(4)
153GENERATE_SYSCALL_FUNC(5)
154GENERATE_SYSCALL_FUNC(6)
155
156#endif	/* _ASM_SYSCALL_H */