[PATCH v2 2/5] nolibc: add support for s390

Sven Schnelle
2023-01-02T10:52:26Z

Use arch-x86_64 as a template. Not really different, but
we have our own mmap syscall which takes a structure instead
of discrete arguments.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
---
tools/include/nolibc/arch-s390.h | 213 +++++++++++++++++++++++++++++++
tools/include/nolibc/arch.h | 2 +
tools/include/nolibc/sys.h | 2 +
3 files changed, 217 insertions(+)
create mode 100644 tools/include/nolibc/arch-s390.h

diff --git a/tools/include/nolibc/arch-s390.h b/tools/include/nolibc/arch-s390.h
new file mode 100644
index 000000000000..df96d8f830a7
--- /dev/null
+++ b/tools/include/nolibc/arch-s390.h
@@ -0,0 +1,213 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * s390 specific definitions for NOLIBC
+ */
+
+#ifndef _NOLIBC_ARCH_S390_H
+#define _NOLIBC_ARCH_S390_H
+#include <asm/unistd.h>
+
+/* O_* macros for fcntl/open are architecture-specific */
+#define O_RDONLY 0
+#define O_WRONLY 1
+#define O_RDWR 2
+#define O_CREAT 0x40
+#define O_EXCL 0x80
+#define O_NOCTTY 0x100
+#define O_TRUNC 0x200
+#define O_APPEND 0x400
+#define O_NONBLOCK 0x800
+#define O_DIRECTORY 0x10000
+
+/* The struct returned by the stat() syscall, equivalent to stat64(). The
+ * syscall returns 116 bytes and stops in the middle of __unused.
+ */
+
+struct sys_stat_struct {
+ unsigned long st_dev;
+ unsigned long st_ino;
+ unsigned long st_nlink;
+ unsigned int st_mode;
+ unsigned int st_uid;
+ unsigned int st_gid;
+ unsigned int __pad1;
+ unsigned long st_rdev;
+ unsigned long st_size;
+ unsigned long st_atime;
+ unsigned long st_atime_nsec;
+ unsigned long st_mtime;
+ unsigned long st_mtime_nsec;
+ unsigned long st_ctime;
+ unsigned long st_ctime_nsec;
+ unsigned long st_blksize;
+ long st_blocks;
+ unsigned long __unused[3];
+};
+
+/* Syscalls for s390:
+ * - registers are 64-bit
+ * - syscall number is passed in r1
+ * - arguments are in r2-r7
+ * - the system call is performed by calling the svc instruction
+ * - syscall return value is in r2
+ * - r1 and r2 are clobbered, others are preserved.
+ *
+ * Link s390 ABI: https://github.com/IBM/s390x-abi
+ *
+ */
+
+#define my_syscall0(num) \
+({ \
+ register long _num __asm__ ("1") = (num); \
+ register long _rc __asm__ ("2"); \
+ \
+ __asm__ volatile ( \
+ "svc 0\n" \
+ : "=d"(_rc) \
+ : "d"(_num) \
+ : "memory", "cc" \
+ ); \
+ _rc; \
+})
+
+#define my_syscall1(num, arg1) \
+({ \
+ register long _num __asm__ ("1") = (num); \
+ register long _arg1 __asm__ ("2") = (long)(arg1); \
+ \
+ __asm__ volatile ( \
+ "svc 0\n" \
+ : "+d"(_arg1) \
+ : "d"(_num) \
+ : "memory", "cc" \
+ ); \
+ _arg1; \
+})
+
+#define my_syscall2(num, arg1, arg2) \
+({ \
+ register long _num __asm__ ("1") = (num); \
+ register long _arg1 __asm__ ("2") = (long)(arg1); \
+ register long _arg2 __asm__ ("3") = (long)(arg2); \
+ \
+ __asm__ volatile ( \
+ "svc 0\n" \
+ : "+d"(_arg1) \
+ : "d"(_arg2), "d"(_num) \
+ : "memory", "cc" \
+ ); \
+ _arg1; \
+})
+
+#define my_syscall3(num, arg1, arg2, arg3) \
+({ \
+ register long _num __asm__ ("1") = (num); \
+ register long _arg1 __asm__ ("2") = (long)(arg1); \
+ register long _arg2 __asm__ ("3") = (long)(arg2); \
+ register long _arg3 __asm__ ("4") = (long)(arg3); \
+ \
+ __asm__ volatile ( \
+ "svc 0\n" \
+ : "+d"(_arg1) \
+ : "d"(_arg2), "d"(_arg3), "d"(_num) \
+ : "memory", "cc" \
+ ); \
+ _arg1; \
+})
+
+#define my_syscall4(num, arg1, arg2, arg3, arg4) \
+({ \
+ register long _num __asm__ ("1") = (num); \
+ register long _arg1 __asm__ ("2") = (long)(arg1); \
+ register long _arg2 __asm__ ("3") = (long)(arg2); \
+ register long _arg3 __asm__ ("4") = (long)(arg3); \
+ register long _arg4 __asm__ ("5") = (long)(arg4); \
+ \
+ __asm__ volatile ( \
+ "svc 0\n" \
+ : "+d"(_arg1) \
+ : "d"(_arg2), "d"(_arg3), "d"(_arg4), "d"(_num) \
+ : "memory", "cc" \
+ ); \
+ _arg1; \
+})
+
+#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
+({ \
+ register long _num __asm__ ("1") = (num); \
+ register long _arg1 __asm__ ("2") = (long)(arg1); \
+ register long _arg2 __asm__ ("3") = (long)(arg2); \
+ register long _arg3 __asm__ ("4") = (long)(arg3); \
+ register long _arg4 __asm__ ("5") = (long)(arg4); \
+ register long _arg5 __asm__ ("6") = (long)(arg5); \
+ \
+ __asm__ volatile ( \
+ "svc 0\n" \
+ : "+d"(_arg1) \
+ : "d"(_arg2), "d"(_arg3), "d"(_arg4), "d"(_arg5), \
+ "d"(_num) \
+ : "memory", "cc" \
+ ); \
+ _arg1; \
+})
+
+#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
+({ \
+ register long _num __asm__ ("1") = (num); \
+ register long _arg1 __asm__ ("2") = (long)(arg1); \
+ register long _arg2 __asm__ ("3") = (long)(arg2); \
+ register long _arg3 __asm__ ("4") = (long)(arg3); \
+ register long _arg4 __asm__ ("5") = (long)(arg4); \
+ register long _arg5 __asm__ ("6") = (long)(arg5); \
+ register long _arg6 __asm__ ("7") = (long)(arg6); \
+ \
+ __asm__ volatile ( \
+ "svc 0\n" \
+ : "+d"(_arg1) \
+ : "d"(_arg2), "d"(_arg3), "d"(_arg4), "d"(_arg5), \
+ "d"(_arg6), "d"(_num) \
+ : "memory", "cc" \
+ ); \
+ _arg1; \
+})
+
+/* startup code */
+__asm__ (".section .text\n"
+ ".weak _start\n"
+ "_start:\n"
+ "lg %r2,0(%r15)\n" /* argument count */
+ "la %r3,8(%r15)\n" /* argument pointers */
+ "la %r4,24(%r15)\n" /* environment pointers */
+ "aghi %r15,-160\n" /* allocate new stackframe */
+ "xc 0(8,%r15),0(%r15)\n" /* clear backchain */
+ "brasl %r14,main\n" /* ret value of main is arg to exit */
+ "lghi %r1,1\n" /* __NR_exit */
+ "svc 0\n"
+ "");
+
+struct s390_mmap_arg_struct {
+ unsigned long addr;
+ unsigned long len;
+ unsigned long prot;
+ unsigned long flags;
+ unsigned long fd;
+ unsigned long offset;
+};
+
+static __attribute__((unused))
+void *sys_mmap(void *addr, size_t length, int prot, int flags, int fd,
+ off_t offset)
+{
+ struct s390_mmap_arg_struct args = {
+ .addr = (unsigned long)addr,
+ .len = (unsigned long)length,
+ .prot = prot,
+ .flags = flags,
+ .fd = fd,
+ .offset = (unsigned long)offset
+ };
+
+ return (void *)my_syscall1(__NR_mmap, &args);
+}
+#define sys_mmap sys_mmap
+#endif // _NOLIBC_ARCH_S390_H
diff --git a/tools/include/nolibc/arch.h b/tools/include/nolibc/arch.h
index 4c6992321b0d..fcded65b98d7 100644
--- a/tools/include/nolibc/arch.h
+++ b/tools/include/nolibc/arch.h
@@ -27,6 +27,8 @@
#include "arch-mips.h"
#elif defined(__riscv)
#include "arch-riscv.h"
+#elif defined(__s390x__)
+#include "arch-s390x.h"
#endif

#endif /* _NOLIBC_ARCH_H */
diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
index ce3ee03aa679..3db1dd8c74ee 100644
--- a/tools/include/nolibc/sys.h
+++ b/tools/include/nolibc/sys.h
@@ -686,6 +686,7 @@ int mknod(const char *path, mode_t mode, dev_t dev)
#define MAP_FAILED ((void *)-1)
#endif

+#ifndef sys_mmap
static __attribute__((unused))
void *sys_mmap(void *addr, size_t length, int prot, int flags, int fd,
off_t offset)
@@ -707,6 +708,7 @@ void *sys_mmap(void *addr, size_t length, int prot, int flags, int fd,
return (void *)my_syscall6(n, addr, length, prot, flags, fd, offset);
#endif
}
+#endif

static __attribute__((unused))
void *mmap(void *addr, size_t length, int prot, int flags, int fd, off_t offset)
--
2.34.1