glibc/sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h

/* Assembler macros for 64 bit S/390.
   Copyright (C) 2001-2015 Free Software Foundation, Inc.
   Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
   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
   <http://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 <dl-sysdep.h>	/* For RTLD_PRIVATE_ERRNO.  */
#include <tls.h>

/* Define __set_errno() for INLINE_SYSCALL macro below.  */
#ifndef __ASSEMBLER__
#include <errno.h>
#endif

/* 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

/*
 * Newer kernel versions redefined __NR_pread and __NR_pwrite to
 * __NR_pread64 and __NR_pwrite64.
 */
#ifndef __NR_pread
# define __NR_pread __NR_pread64
#endif
#ifndef __NR_pwrite
# define __NR_pwrite __NR_pwrite64
#endif

#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)

#ifndef PIC
# define SYSCALL_ERROR_LABEL syscall_error
# define SYSCALL_ERROR_HANDLER
#else
# if RTLD_PRIVATE_ERRNO
#  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
#  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
#  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

#endif /* __ASSEMBLER__ */

#undef INLINE_SYSCALL
#define INLINE_SYSCALL(name, nr, args...)				      \
  ({									      \
    long _ret = INTERNAL_SYSCALL (name, , nr, args);			      \
    if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (_ret, )))		      \
     {									      \
       __set_errno (INTERNAL_SYSCALL_ERRNO (_ret, ));			      \
       _ret = -1;							      \
     }									      \
    _ret; })

#undef INTERNAL_SYSCALL_DECL
#define INTERNAL_SYSCALL_DECL(err) do { } while (0)

#undef INTERNAL_SYSCALL_DIRECT
#define INTERNAL_SYSCALL_DIRECT(name, err, nr, args...)			      \
  ({									      \
    DECLARGS_##nr(args)							      \
    register long _ret asm("2");					      \
    asm volatile (							      \
    "svc    %b1\n\t"							      \
    : "=d" (_ret)							      \
    : "i" (__NR_##name) ASMFMT_##nr					      \
    : "memory" );							      \
    _ret; })

#undef INTERNAL_SYSCALL_SVC0
#define INTERNAL_SYSCALL_SVC0(name, err, nr, args...)			      \
  ({									      \
    DECLARGS_##nr(args)							      \
    register unsigned long _nr asm("1") = (unsigned long)(__NR_##name);	      \
    register long _ret asm("2");					      \
    asm volatile (							      \
    "svc    0\n\t"							      \
    : "=d" (_ret)							      \
    : "d" (_nr) ASMFMT_##nr						      \
    : "memory" );							      \
    _ret; })

#undef INTERNAL_SYSCALL_NCS
#define INTERNAL_SYSCALL_NCS(no, err, nr, args...)			      \
  ({									      \
    DECLARGS_##nr(args)							      \
    register unsigned long _nr asm("1") = (unsigned long)(no);		      \
    register long _ret asm("2");					      \
    asm volatile (							      \
    "svc    0\n\t"							      \
    : "=d" (_ret)							      \
    : "d" (_nr) ASMFMT_##nr						      \
    : "memory" );							      \
    _ret; })

#undef INTERNAL_SYSCALL
#define INTERNAL_SYSCALL(name, err, nr, args...)			      \
  (((__NR_##name) < 256) ?						      \
    INTERNAL_SYSCALL_DIRECT(name, err, nr, args) :			      \
    INTERNAL_SYSCALL_SVC0(name, err,nr, args))

#undef INTERNAL_SYSCALL_ERROR_P
#define INTERNAL_SYSCALL_ERROR_P(val, err)				      \
  ((unsigned long) (val) >= -4095UL)

#undef INTERNAL_SYSCALL_ERRNO
#define INTERNAL_SYSCALL_ERRNO(val, err)	(-(val))

#define DECLARGS_0()
#define DECLARGS_1(arg1) \
	register unsigned long gpr2 asm ("2") = (unsigned long)(arg1);
#define DECLARGS_2(arg1, arg2) \
	DECLARGS_1(arg1) \
	register unsigned long gpr3 asm ("3") = (unsigned long)(arg2);
#define DECLARGS_3(arg1, arg2, arg3) \
	DECLARGS_2(arg1, arg2) \
	register unsigned long gpr4 asm ("4") = (unsigned long)(arg3);
#define DECLARGS_4(arg1, arg2, arg3, arg4) \
	DECLARGS_3(arg1, arg2, arg3) \
	register unsigned long gpr5 asm ("5") = (unsigned long)(arg4);
#define DECLARGS_5(arg1, arg2, arg3, arg4, arg5) \
	DECLARGS_4(arg1, arg2, arg3, arg4) \
	register unsigned long gpr6 asm ("6") = (unsigned long)(arg5);
#define DECLARGS_6(arg1, arg2, arg3, arg4, arg5, arg6) \
	DECLARGS_5(arg1, arg2, arg3, arg4, arg5) \
	register unsigned long gpr7 asm ("7") = (unsigned long)(arg6);

#define ASMFMT_0
#define ASMFMT_1 , "0" (gpr2)
#define ASMFMT_2 , "0" (gpr2), "d" (gpr3)
#define ASMFMT_3 , "0" (gpr2), "d" (gpr3), "d" (gpr4)
#define ASMFMT_4 , "0" (gpr2), "d" (gpr3), "d" (gpr4), "d" (gpr5)
#define ASMFMT_5 , "0" (gpr2), "d" (gpr3), "d" (gpr4), "d" (gpr5), "d" (gpr6)
#define ASMFMT_6 , "0" (gpr2), "d" (gpr3), "d" (gpr4), "d" (gpr5), "d" (gpr6), "d" (gpr7)

#define CLOBBER_0 , "3", "4", "5"
#define CLOBBER_1 , "3", "4", "5"
#define CLOBBER_2 , "4", "5"
#define CLOBBER_3 , "5"
#define CLOBBER_4
#define CLOBBER_5
#define CLOBBER_6

/* List of system calls which are supported as vsyscalls.  */
#define HAVE_CLOCK_GETRES_VSYSCALL	1
#define HAVE_CLOCK_GETTIME_VSYSCALL	1

/* This version is for kernels that implement system calls that
   behave like function calls as far as register saving.
   It falls back to the syscall in the case that the vDSO doesn't
   exist or fails for ENOSYS */
#ifdef SHARED
# define INLINE_VSYSCALL(name, nr, args...) \
  ({									      \
    __label__ out;							      \
    __label__ iserr;							      \
    long int _ret;							      \
									      \
    if (__vdso_##name != NULL)						      \
      {									      \
	_ret = INTERNAL_VSYSCALL_NCS (__vdso_##name, , nr, ##args);	      \
	if (!INTERNAL_SYSCALL_ERROR_P (_ret, ))				      \
	  goto out;							      \
	if (INTERNAL_SYSCALL_ERRNO (_ret, ) != ENOSYS)			      \
	  goto iserr;							      \
      }									      \
									      \
    _ret = INTERNAL_SYSCALL (name, , nr, ##args);			      \
    if (INTERNAL_SYSCALL_ERROR_P (_ret, ))				      \
      {									      \
      iserr:								      \
	__set_errno (INTERNAL_SYSCALL_ERRNO (_ret, ));			      \
	_ret = -1L;							      \
      }									      \
  out:									      \
    (int) _ret;								      \
  })
#else
# define INLINE_VSYSCALL(name, nr, args...) \
  INLINE_SYSCALL (name, nr, ##args)
#endif

#ifdef SHARED
# define INTERNAL_VSYSCALL(name, err, nr, args...) \
  ({									      \
    __label__ out;							      \
    long int _ret;							      \
									      \
    if (__vdso_##name != NULL)						      \
      {									      \
	_ret = INTERNAL_VSYSCALL_NCS (__vdso_##name, err, nr, ##args);	      \
	if (!INTERNAL_SYSCALL_ERROR_P (_ret, err)			      \
	    || INTERNAL_SYSCALL_ERRNO (_ret, err) != ENOSYS)		      \
	  goto out;							      \
      }									      \
    _ret = INTERNAL_SYSCALL (name, err, nr, ##args);			      \
  out:									      \
    _ret;								      \
  })
#else
# define INTERNAL_VSYSCALL(name, err, nr, args...) \
  INTERNAL_SYSCALL (name, err, nr, ##args)
#endif

/* This version is for internal uses when there is no desire
   to set errno */
#define INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK(name, err, nr, args...)	      \
  ({									      \
    long int _ret = ENOSYS;						      \
									      \
    if (__vdso_##name != NULL)						      \
      _ret = INTERNAL_VSYSCALL_NCS (__vdso_##name, err, nr, ##args);	      \
    else								      \
      err = 1 << 28;							      \
    _ret;								      \
  })

#define INTERNAL_VSYSCALL_NCS(fn, err, nr, args...)			      \
  ({									      \
    DECLARGS_##nr(args)							      \
    register long _ret asm("2");					      \
    asm volatile (							      \
    "lgr 10,14\n\t"                                                          \
    "basr 14,%1\n\t"							      \
    "lgr 14,10\n\t"                                                          \
    : "=d" (_ret)							      \
    : "a" (fn) ASMFMT_##nr						      \
    : "cc", "memory", "0", "1", "10" CLOBBER_##nr);                          \
    _ret; })

/* 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 */