Re: is sysdep-cancel.h needed for any linux arch?

[Franz Sirl <Franz dot Sirl-kernel at lauterbach dot com>]

On Saturday 04 January 2003 01:01, Jakub Jelinek wrote:
> On Sat, Jan 04, 2003 at 12:55:35AM +0100, Franz Sirl wrote:
> > > The semantics outside the macro hasn't changed.  PSEUDO is used exactly
> > > as before.  Normally there is only the return opcode following the
> > > PSEUDO.
> >
> > Usually PSEUDO is used in some script-generated assembler stubs and I
> > couldn't find if anything  special was emitted after it. On PPC "ret"
> > handles both the error and non-error syscall returns.
>
> But of course, if it is not what you want in the cancellable PSEUDO();
> ret; PSEUDO_END() sequence, you can #undef PSEUDO_RET and define it
> to something different, even to nothing in sysdep-cancel.h.

I just wanted to make sure nothing comes in-between PSEUDO(); ret;. If that's 
assured, all is fine.

So, my initial version seems to work in the pthread case, but in the libc case 
it crashes in __libc_enable_asynccancel while calling  
(*__libc_pthread_functions.ptr_pthread_thread_self)() which is zero. As this 
happens still during library init, who is responsible for initing the 
__libc_pthread_functions struct with the proper values?

Franz.

/* Copyright (C) 2003 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Franz Sirl <Franz.Sirl-kernel@lauterbach.com>, 2003.

   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, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <sysdep.h>
#ifndef __ASSEMBLER__
# include <linuxthreads/internals.h>
#endif

#if !defined NOT_IN_libc || defined IS_IN_libpthread

# undef PSEUDO
# define PSEUDO(name, syscall_name, args)				\
  .section ".text";							\
  ENTRY (name)								\
    SINGLE_THREAD_P;							\
    bne .Lpseudo_cancel;						\
    DO_CALL (SYS_ify (syscall_name));						\
    PSEUDO_RET;								\
  .Lpseudo_cancel:							\
    stwu 1,-48(1);							\
    mflr 9;								\
    stw 9,52(1);							\
    DOCARGS_##args;	/* save syscall args around CENABLE.  */						\
    CENABLE;								\
    stw 3,16(1);	/* store CENABLE return value (MASK).  */						\
    UNDOCARGS_##args;	/* restore syscall args.  */						\
    DO_CALL (SYS_ify (syscall_name));						\
    mfcr 0;		/* save CR/R3 around CDISABLE.  */						\
    stw 3,8(1);								\
    stw 0,12(1);							\
    lwz 3,16(1);	/* pass MASK to CDISABLE.  */						\
    CDISABLE;								\
    lwz 4,52(1);							\
    lwz 0,12(1);	/* restore CR/R3. */						\
    lwz 3,8(1);								\
    mtlr 4;								\
    mtcr 0;								\
    addi 1,1,48;

# define DOCARGS_0
# define UNDOCARGS_0

# define DOCARGS_1	stw 3,20(1); DOCARGS_0
# define UNDOCARGS_1	lwz 3,20(1); UNDOCARGS_0

# define DOCARGS_2	stw 4,24(1); DOCARGS_1
# define UNDOCARGS_2	lwz 4,24(1); UNDOCARGS_1

# define DOCARGS_3	stw 5,28(1); DOCARGS_2
# define UNDOCARGS_3	lwz 5,28(1); UNDOCARGS_2

# define DOCARGS_4	stw 6,32(1); DOCARGS_3
# define UNDOCARGS_4	lwz 6,32(1); UNDOCARGS_3

# define DOCARGS_5	stw 7,36(1); DOCARGS_4
# define UNDOCARGS_5	lwz 7,36(1); UNDOCARGS_4

# ifdef IS_IN_libpthread
#  define CENABLE	bl JUMPTARGET(__pthread_enable_asynccancel)
#  define CDISABLE	bl JUMPTARGET(__pthread_disable_asynccancel)
#  define __local_multiple_threads __pthread_multiple_threads
# else
#  define CENABLE	bl JUMPTARGET(__libc_enable_asynccancel)
#  define CDISABLE	bl JUMPTARGET(__libc_disable_asynccancel)
#  define __local_multiple_threads __libc_multiple_threads
# endif

# ifndef __ASSEMBLER__
extern int __local_multiple_threads attribute_hidden;
#  define SINGLE_THREAD_P __builtin_expect (__local_multiple_threads == 0, 1)
# else
#  if !defined PIC
#   define SINGLE_THREAD_P \
  lis 10,__local_multiple_threads@h; \
  lwz 10,__local_multiple_threads@l(10); \
  cmpli 0,10,0
#  else
#   if !defined HAVE_HIDDEN || !USE___THREAD
#    define SINGLE_THREAD_P \
  mflr 9; \
  bl _GLOBAL_OFFSET_TABLE_@local-4; \
  mflr 10; \
  mtlr 9; \
  lwz 10,__local_multiple_threads@got(10); \
  cmpli 0,10,0
#   else
#    define SINGLE_THREAD_P \
  mflr 9; \
  bl _GLOBAL_OFFSET_TABLE_@local-4; \
  mflr 10; \
  mtlr 9; \
  lwz 10,__local_multiple_threads@got(10); \
  cmpli 0,10,0
#   endif
#  endif
# endif

#elif !defined __ASSEMBLER__

/* This code should never be used but we define it anyhow.  */
# define SINGLE_THREAD_P (1)

#endif