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