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Avoid tickling a linker bug from microblaze pt-vfork.S.

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libpthread used to have its own vfork implementation that differed
from libc's only in having a pointless micro-optimization.  There is
no longer any use to having a separate copy in libpthread, but the
historical ABI requires a compatibility shim.  microblaze was trying
to be slightly too clever about how it did this, and tickled a linker
bug.  The linker bug should get fixed eventually, but there's no
reason for us to keep tickling it in the meantime.

This doesn't reuse the generic pt-vfork.c because microblaze doesn't
have IFUNC support yet, and it doesn't reuse aarch64/pt-vfork.c
because that fails to generate a tailcall (with GCC 7.1.1).

	* sysdeps/unix/sysv/linux/microblaze/pt-vfork.S: Don't include
	alpha/pt-vfork.S.  Provide own compat shim for vfork and __vfork.
	* sysdeps/unix/sysv/linux/microblaze/vfork.S: Add __libc_vfork alias.
	* sysdeps/unix/sysv/linux/microblaze/localplt.data:
	libpthread.so no longer references __errno_location.
This commit is contained in:
Zack Weinberg 2017-05-30 21:05:04 -04:00
parent 52bd938169
commit 491bb0858e
4 changed files with 58 additions and 2 deletions
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8
ChangeLog
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@ -1,3 +1,11 @@
2017-06-01 Zack Weinberg <zackw@panix.com>
* sysdeps/unix/sysv/linux/microblaze/pt-vfork.S: Don't include
alpha/pt-vfork.S. Provide own compat shim for vfork and __vfork.
* sysdeps/unix/sysv/linux/microblaze/vfork.S: Add __libc_vfork alias.
* sysdeps/unix/sysv/linux/microblaze/localplt.data:
libpthread.so no longer references __errno_location.
2017-05-31 Adhemerval Zanella <adhemerval.zanella@linaro.org>
* NEWS: Add note about pwritev2 and preadv2 inclusion.

1
sysdeps/unix/sysv/linux/microblaze/localplt.data
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@ -5,7 +5,6 @@ libc.so: malloc
libc.so: memalign
libc.so: realloc
libm.so: matherr
libpthread.so: __errno_location
# The dynamic loader needs __tls_get_addr for TLS.
ld.so: __tls_get_addr ?
# The main malloc is interposed into the dynamic linker, for

50
sysdeps/unix/sysv/linux/microblaze/pt-vfork.S
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@ -1 +1,49 @@
#include <sysdeps/unix/sysv/linux/alpha/pt-vfork.S>
/* vfork ABI-compatibility entry points for libpthread.
Copyright (C) 2014-2017 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
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <shlib-compat.h>
/* libpthread used to have its own vfork implementation that differed
from libc's only in having a pointless micro-optimization. There
is no longer any use to having a separate copy in libpthread, but
the historical ABI requires it. For static linking, there is no
need to provide anything here--the libc version will be linked in.
For shared library ABI compatibility, there must be __vfork and
vfork symbols in libpthread.so.
As of GCC 7, microblaze can *not* rely on the compiler to generate
a tail call from this vfork to __libc_vfork. */
#if (SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_20) \
|| SHLIB_COMPAT (libpthread, GLIBC_2_1_2, GLIBC_2_20))
ENTRY (vfork_compat)
bri __libc_vfork
END (vfork_compat)
#endif
#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_20)
compat_symbol (libpthread, vfork_compat, vfork, GLIBC_2_0)
#endif
#if SHLIB_COMPAT (libpthread, GLIBC_2_1_2, GLIBC_2_20)
strong_alias (vfork_compat, vfork_compat2)
compat_symbol (libpthread, vfork_compat2, __vfork, GLIBC_2_1_2)
#endif

1
sysdeps/unix/sysv/linux/microblaze/vfork.S
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@ -43,3 +43,4 @@ PSEUDO_END (__vfork)
libc_hidden_def (__vfork)
weak_alias (__vfork, vfork)
strong_alias (__vfork, __libc_vfork)