text: /* Copyright (C) 2000-2016 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/s390-32/sysdep.h>
  #include <sysdeps/unix/sysdep.h>
  #include <sysdeps/unix/sysv/linux/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
  
  #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);                                             \
      lhi  %r4,-4095 ;                                                          \
      clr  %r2,%r4 ;							      \
      jnl  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)					      \
    END (name)
  
  #undef PSEUDO_ERRVAL
  #define	PSEUDO_ERRVAL(name, syscall_name, args)				      \
    .text;                                                                      \
    ENTRY (name)								      \
      DO_CALL (syscall_name, args);					      \
      lcr %r2,%r2
  
  #undef PSEUDO_END_ERRVAL
  #define PSEUDO_END_ERRVAL(name)						      \
    END (name)
  
  #ifndef PIC
  # define SYSCALL_ERROR_LABEL 0f
  # define SYSCALL_ERROR_HANDLER \
  0:  basr  %r1,0;							      \
  1:  l     %r1,2f-1b(%r1);						      \
      br    %r1;								      \
  2:  .long syscall_error
  #else
  # if RTLD_PRIVATE_ERRNO
  #  define SYSCALL_ERROR_LABEL 0f
  #  define SYSCALL_ERROR_HANDLER \
  0:  basr  %r1,0;							      \
  1:  al    %r1,2f-1b(%r1);						      \
      lcr   %r2,%r2;							      \
      st    %r2,0(%r1);							      \
      lhi   %r2,-1;							      \
      br    %r14;								      \
  2:  .long rtld_errno-1b
  # 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;							      \
      basr  %r1,0;							      \
  1:  al    %r1,2f-1b(%r1);						      \
      l     %r1,SYSCALL_ERROR_ERRNO@gotntpoff(%r1);			      \
      ear   %r2,%a0;							      \
      st    %r0,0(%r1,%r2);						      \
      lhi   %r2,-1;							      \
      br    %r14;								      \
  2:  .long _GLOBAL_OFFSET_TABLE_-1b
  # else
  #  define SYSCALL_ERROR_LABEL 0f
  #  define SYSCALL_ERROR_HANDLER \
  0:  basr  %r1,0;							      \
  1:  al    %r1,2f-1b(%r1);						      \
      l     %r1,errno@GOT(%r1);						      \
      lcr   %r2,%r2;							      \
      st    %r2,0(%r1);							      \
      lhi   %r2,-1;							      \
      br    %r14;								      \
  2:  .long _GLOBAL_OFFSET_TABLE_-1b
  # 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;								      \
      lr %r0,%r7;								      \
      l %r7,96(%r15);							      \
    .endif;								      \
    .if SYS_ify (syscall) < 256;						      \
      svc SYS_ify (syscall);						      \
    .else;								      \
      lhi %r1,SYS_ify (syscall);						      \
      svc 0;								      \
    .endif;								      \
    .if args > 5;								      \
      lr %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...)				      \
    ({									      \
      unsigned int _ret = INTERNAL_SYSCALL (name, , nr, args);		      \
      if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (_ret, )))		      \
       {									      \
         __set_errno (INTERNAL_SYSCALL_ERRNO (_ret, ));			      \
         _ret = 0xffffffff;						      \
       }									      \
      (int) _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 int _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 int _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 int _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 int) (val) >= 0xfffff001u)
  
  #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
  #define HAVE_GETTIMEOFDAY_VSYSCALL	1
  
  /* 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;						      \
  									      \
      __typeof (__vdso_##name) vdsop = __vdso_##name;			      \
      PTR_DEMANGLE (vdsop);						      \
      if (vdsop != NULL)							      \
        _ret = INTERNAL_VSYSCALL_CALL (vdsop, err, nr, ##args);		      \
      else								      \
        err = 1 << 28;							      \
      _ret;								      \
    })
  
  #define INTERNAL_VSYSCALL_CALL(fn, err, nr, args...)			      \
    ({									      \
      DECLARGS_##nr(args)							      \
      register long _ret __asm__("2");					      \
      __asm__ __volatile__ (						      \
  			  "lr 10,14\n\t"				      \
  			  "basr 14,%1\n\t"				      \
  			  "lr 14,10\n\t"				      \
  			  : "=d" (_ret)					      \
  			  : "d" (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;			\
    x       reg,STACK_GUARD(tmpreg)
  #  define PTR_MANGLE2(reg, tmpreg) \
    x       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 */
  