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/* Assembler macros for 64 bit S/390.
Copyright (C) 2001-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#ifndef _LINUX_S390_SYSDEP_H
#define _LINUX_S390_SYSDEP_H
#include <sysdeps/s390/s390-64/sysdep.h>
#include <sysdeps/unix/sysdep.h>
#include <sysdeps/unix/sysv/linux/s390/sysdep.h>
#include <sysdeps/unix/sysv/linux/sysdep.h>
#include <dl-sysdep.h> /* For RTLD_PRIVATE_ERRNO. */
#include <tls.h>
/* For Linux we can use the system call table in the header file
/usr/include/asm/unistd.h
of the kernel. But these symbols do not follow the SYS_* syntax
so we have to redefine the `SYS_ify' macro here. */
/* In newer 2.1 kernels __NR_syscall is missing so we define it here. */
#define __NR_syscall 0
#undef SYS_ify
#define SYS_ify(syscall_name) __NR_##syscall_name
#ifdef __ASSEMBLER__
/* Linux uses a negative return value to indicate syscall errors, unlike
most Unices, which use the condition codes' carry flag.
Since version 2.1 the return value of a system call might be negative
even if the call succeeded. E.g., the `lseek' system call might return
a large offset. Therefore we must not anymore test for < 0, but test
for a real error by making sure the value in gpr2 is a real error
number. Linus said he will make sure that no syscall returns a value
in -1 .. -4095 as a valid result so we can savely test with -4095. */
#undef PSEUDO
#define PSEUDO(name, syscall_name, args) \
.text; \
ENTRY (name) \
DO_CALL (syscall_name, args); \
lghi %r4,-4095 ; \
clgr %r2,%r4 ; \
jgnl SYSCALL_ERROR_LABEL
#undef PSEUDO_END
#define PSEUDO_END(name) \
SYSCALL_ERROR_HANDLER; \
END (name)
#undef PSEUDO_NOERRNO
#define PSEUDO_NOERRNO(name, syscall_name, args) \
.text; \
ENTRY (name) \
DO_CALL (syscall_name, args)
#undef PSEUDO_END_NOERRNO
#define PSEUDO_END_NOERRNO(name) \
SYSCALL_ERROR_HANDLER; \
END (name)
#undef PSEUDO_ERRVAL
#define PSEUDO_ERRVAL(name, syscall_name, args) \
.text; \
ENTRY (name) \
DO_CALL (syscall_name, args); \
lcgr %r2,%r2
#undef PSEUDO_END_ERRVAL
#define PSEUDO_END_ERRVAL(name) \
SYSCALL_ERROR_HANDLER; \
END (name)
#undef SYSCALL_ERROR_LABEL
#ifndef PIC
# undef SYSCALL_ERROR_LABEL
# define SYSCALL_ERROR_LABEL syscall_error
# define SYSCALL_ERROR_HANDLER
#else
# if RTLD_PRIVATE_ERRNO
# undef SYSCALL_ERROR_LABEL
# define SYSCALL_ERROR_LABEL 0f
# define SYSCALL_ERROR_HANDLER \
0: larl %r1,rtld_errno; \
lcr %r2,%r2; \
st %r2,0(%r1); \
lghi %r2,-1; \
br %r14
# elif defined _LIBC_REENTRANT
# if IS_IN (libc)
# define SYSCALL_ERROR_ERRNO __libc_errno
# else
# define SYSCALL_ERROR_ERRNO errno
# endif
# undef SYSCALL_ERROR_LABEL
# define SYSCALL_ERROR_LABEL 0f
# define SYSCALL_ERROR_HANDLER \
0: lcr %r0,%r2; \
larl %r1,SYSCALL_ERROR_ERRNO@indntpoff; \
lg %r1,0(%r1); \
ear %r2,%a0; \
sllg %r2,%r2,32; \
ear %r2,%a1; \
st %r0,0(%r1,%r2); \
lghi %r2,-1; \
br %r14
# else
# undef SYSCALL_ERROR_LABEL
# define SYSCALL_ERROR_LABEL 0f
# define SYSCALL_ERROR_HANDLER \
0: larl %r1,_GLOBAL_OFFSET_TABLE_; \
lg %r1,errno@GOT(%r1); \
lcr %r2,%r2; \
st %r2,0(%r1); \
lghi %r2,-1; \
br %r14
# endif /* _LIBC_REENTRANT */
#endif /* PIC */
/* Linux takes system call arguments in registers:
syscall number 1 call-clobbered
arg 1 2 call-clobbered
arg 2 3 call-clobbered
arg 3 4 call-clobbered
arg 4 5 call-clobbered
arg 5 6 call-saved
arg 6 7 call-saved
(Of course a function with say 3 arguments does not have entries for
arguments 4 and 5.)
For system calls with 6 parameters a stack operation is required
to load the 6th parameter to register 7. Call saved register 7 is
moved to register 0 and back to avoid an additional stack frame.
*/
#define DO_CALL(syscall, args) \
.if args > 5; \
lgr %r0,%r7; \
lg %r7,160(%r15); \
.endif; \
.if SYS_ify (syscall) < 256; \
svc SYS_ify (syscall); \
.else; \
lghi %r1,SYS_ify (syscall); \
svc 0; \
.endif; \
.if args > 5; \
lgr %r7,%r0; \
.endif
#define ret \
br 14
#define ret_NOERRNO \
br 14
#define ret_ERRVAL \
br 14
#else
# undef HAVE_INTERNAL_BRK_ADDR_SYMBOL
# define HAVE_INTERNAL_BRK_ADDR_SYMBOL 1
#endif /* __ASSEMBLER__ */
/* Pointer mangling support. */
#if IS_IN (rtld)
/* We cannot use the thread descriptor because in ld.so we use setjmp
earlier than the descriptor is initialized. */
#else
/* For the time being just use stack_guard rather than a separate
pointer_guard. */
# ifdef __ASSEMBLER__
# define PTR_MANGLE(reg, tmpreg) \
ear tmpreg,%a0; \
sllg tmpreg,tmpreg,32; \
ear tmpreg,%a1; \
xg reg,STACK_GUARD(tmpreg)
# define PTR_MANGLE2(reg, tmpreg) \
xg reg,STACK_GUARD(tmpreg)
# define PTR_DEMANGLE(reg, tmpreg) PTR_MANGLE (reg, tmpreg)
# else
# define PTR_MANGLE(var) \
(var) = (void *) ((uintptr_t) (var) ^ THREAD_GET_POINTER_GUARD ())
# define PTR_DEMANGLE(var) PTR_MANGLE (var)
# endif
#endif
#endif /* _LINUX_S390_SYSDEP_H */
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