From 491bb0858e2d7edc36ced616e846803671d8db75 Mon Sep 17 00:00:00 2001 From: Zack Weinberg Date: Tue, 30 May 2017 21:05:04 -0400 Subject: [PATCH] Avoid tickling a linker bug from microblaze pt-vfork.S. 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. --- ChangeLog | 8 +++ .../unix/sysv/linux/microblaze/localplt.data | 1 - sysdeps/unix/sysv/linux/microblaze/pt-vfork.S | 50 ++++++++++++++++++- sysdeps/unix/sysv/linux/microblaze/vfork.S | 1 + 4 files changed, 58 insertions(+), 2 deletions(-) diff --git a/ChangeLog b/ChangeLog index c0d9d6d212..d0bed8aa24 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,11 @@ +2017-06-01 Zack Weinberg + + * 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 * NEWS: Add note about pwritev2 and preadv2 inclusion. diff --git a/sysdeps/unix/sysv/linux/microblaze/localplt.data b/sysdeps/unix/sysv/linux/microblaze/localplt.data index a61b94dfb8..ca476bedd8 100644 --- a/sysdeps/unix/sysv/linux/microblaze/localplt.data +++ b/sysdeps/unix/sysv/linux/microblaze/localplt.data @@ -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 diff --git a/sysdeps/unix/sysv/linux/microblaze/pt-vfork.S b/sysdeps/unix/sysv/linux/microblaze/pt-vfork.S index 65cc3823ac..f201f0429f 100644 --- a/sysdeps/unix/sysv/linux/microblaze/pt-vfork.S +++ b/sysdeps/unix/sysv/linux/microblaze/pt-vfork.S @@ -1 +1,49 @@ -#include +/* 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 + . */ + +#include +#include + +/* 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 diff --git a/sysdeps/unix/sysv/linux/microblaze/vfork.S b/sysdeps/unix/sysv/linux/microblaze/vfork.S index 1ad86229a9..f1e4508d20 100644 --- a/sysdeps/unix/sysv/linux/microblaze/vfork.S +++ b/sysdeps/unix/sysv/linux/microblaze/vfork.S @@ -43,3 +43,4 @@ PSEUDO_END (__vfork) libc_hidden_def (__vfork) weak_alias (__vfork, vfork) +strong_alias (__vfork, __libc_vfork)