arch-s390.h

  1/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
  2/*
  3 * s390 specific definitions for NOLIBC
  4 */
  5
  6#ifndef _NOLIBC_ARCH_S390_H
  7#define _NOLIBC_ARCH_S390_H
  8#include <linux/signal.h>
  9#include <linux/unistd.h>
 10
 11#include "compiler.h"
 12#include "crt.h"
 13#include "std.h"
 14
 15/* Syscalls for s390:
 16 *   - registers are 64-bit
 17 *   - syscall number is passed in r1
 18 *   - arguments are in r2-r7
 19 *   - the system call is performed by calling the svc instruction
 20 *   - syscall return value is in r2
 21 *   - r1 and r2 are clobbered, others are preserved.
 22 *
 23 * Link s390 ABI: https://github.com/IBM/s390x-abi
 24 *
 25 */
 26
 27#define my_syscall0(num)						\
 28({									\
 29	register long _num __asm__ ("1") = (num);			\
 30	register long _rc __asm__ ("2");				\
 31									\
 32	__asm__ volatile (						\
 33		"svc 0\n"						\
 34		: "=d"(_rc)						\
 35		: "d"(_num)						\
 36		: "memory", "cc"					\
 37		);							\
 38	_rc;								\
 39})
 40
 41#define my_syscall1(num, arg1)						\
 42({									\
 43	register long _num __asm__ ("1") = (num);			\
 44	register long _arg1 __asm__ ("2") = (long)(arg1);		\
 45									\
 46	__asm__ volatile (						\
 47		"svc 0\n"						\
 48		: "+d"(_arg1)						\
 49		: "d"(_num)						\
 50		: "memory", "cc"					\
 51		);							\
 52	_arg1;								\
 53})
 54
 55#define my_syscall2(num, arg1, arg2)					\
 56({									\
 57	register long _num __asm__ ("1") = (num);			\
 58	register long _arg1 __asm__ ("2") = (long)(arg1);		\
 59	register long _arg2 __asm__ ("3") = (long)(arg2);		\
 60									\
 61	__asm__ volatile (						\
 62		"svc 0\n"						\
 63		: "+d"(_arg1)						\
 64		: "d"(_arg2), "d"(_num)					\
 65		: "memory", "cc"					\
 66		);							\
 67	_arg1;								\
 68})
 69
 70#define my_syscall3(num, arg1, arg2, arg3)				\
 71({									\
 72	register long _num __asm__ ("1") = (num);			\
 73	register long _arg1 __asm__ ("2") = (long)(arg1);		\
 74	register long _arg2 __asm__ ("3") = (long)(arg2);		\
 75	register long _arg3 __asm__ ("4") = (long)(arg3);		\
 76									\
 77	__asm__ volatile (						\
 78		"svc 0\n"						\
 79		: "+d"(_arg1)						\
 80		: "d"(_arg2), "d"(_arg3), "d"(_num)			\
 81		: "memory", "cc"					\
 82		);							\
 83	_arg1;								\
 84})
 85
 86#define my_syscall4(num, arg1, arg2, arg3, arg4)			\
 87({									\
 88	register long _num __asm__ ("1") = (num);			\
 89	register long _arg1 __asm__ ("2") = (long)(arg1);		\
 90	register long _arg2 __asm__ ("3") = (long)(arg2);		\
 91	register long _arg3 __asm__ ("4") = (long)(arg3);		\
 92	register long _arg4 __asm__ ("5") = (long)(arg4);		\
 93									\
 94	__asm__ volatile (						\
 95		"svc 0\n"						\
 96		: "+d"(_arg1)						\
 97		: "d"(_arg2), "d"(_arg3), "d"(_arg4), "d"(_num)		\
 98		: "memory", "cc"					\
 99		);							\
100	_arg1;								\
101})
102
103#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5)			\
104({									\
105	register long _num __asm__ ("1") = (num);			\
106	register long _arg1 __asm__ ("2") = (long)(arg1);		\
107	register long _arg2 __asm__ ("3") = (long)(arg2);		\
108	register long _arg3 __asm__ ("4") = (long)(arg3);		\
109	register long _arg4 __asm__ ("5") = (long)(arg4);		\
110	register long _arg5 __asm__ ("6") = (long)(arg5);		\
111									\
112	__asm__ volatile (						\
113		"svc 0\n"						\
114		: "+d"(_arg1)						\
115		: "d"(_arg2), "d"(_arg3), "d"(_arg4), "d"(_arg5),	\
116		  "d"(_num)						\
117		: "memory", "cc"					\
118		);							\
119	_arg1;								\
120})
121
122#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6)		\
123({									\
124	register long _num __asm__ ("1") = (num);			\
125	register long _arg1 __asm__ ("2") = (long)(arg1);		\
126	register long _arg2 __asm__ ("3") = (long)(arg2);		\
127	register long _arg3 __asm__ ("4") = (long)(arg3);		\
128	register long _arg4 __asm__ ("5") = (long)(arg4);		\
129	register long _arg5 __asm__ ("6") = (long)(arg5);		\
130	register long _arg6 __asm__ ("7") = (long)(arg6);		\
131									\
132	__asm__ volatile (						\
133		"svc 0\n"						\
134		: "+d"(_arg1)						\
135		: "d"(_arg2), "d"(_arg3), "d"(_arg4), "d"(_arg5),	\
136		  "d"(_arg6), "d"(_num)					\
137		: "memory", "cc"					\
138		);							\
139	_arg1;								\
140})
141
142#ifndef NOLIBC_NO_RUNTIME
143/* startup code */
144void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
145{
146	__asm__ volatile (
147		"lgr	%r2, %r15\n"          /* save stack pointer to %r2, as arg1 of _start_c */
148		"aghi	%r15, -160\n"         /* allocate new stackframe                        */
149		"xc	0(8,%r15), 0(%r15)\n" /* clear backchain                                */
150		"brasl	%r14, _start_c\n"     /* transfer to c runtime                          */
151	);
152	__nolibc_entrypoint_epilogue();
153}
154#endif /* NOLIBC_NO_RUNTIME */
155
156struct s390_mmap_arg_struct {
157	unsigned long addr;
158	unsigned long len;
159	unsigned long prot;
160	unsigned long flags;
161	unsigned long fd;
162	unsigned long offset;
163};
164
165static __attribute__((unused))
166void *sys_mmap(void *addr, size_t length, int prot, int flags, int fd,
167	       off_t offset)
168{
169	struct s390_mmap_arg_struct args = {
170		.addr = (unsigned long)addr,
171		.len = (unsigned long)length,
172		.prot = prot,
173		.flags = flags,
174		.fd = fd,
175		.offset = (unsigned long)offset
176	};
177
178	return (void *)my_syscall1(__NR_mmap, &args);
179}
180#define sys_mmap sys_mmap
181
182static __attribute__((unused))
183pid_t sys_fork(void)
184{
185	return my_syscall5(__NR_clone, 0, SIGCHLD, 0, 0, 0);
186}
187#define sys_fork sys_fork
188
189#endif /* _NOLIBC_ARCH_S390_H */