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[Bug dynamic-link/21609] Incomplete workaround for GCC __tls_get_addr ABI issue on x86-64
- From: "cvs-commit at gcc dot gnu.org" <sourceware-bugzilla at sourceware dot org>
- To: glibc-bugs at sourceware dot org
- Date: Wed, 05 Jul 2017 13:22:08 +0000
- Subject: [Bug dynamic-link/21609] Incomplete workaround for GCC __tls_get_addr ABI issue on x86-64
- Auto-submitted: auto-generated
- References: <bug-21609-131@http.sourceware.org/bugzilla/>
https://sourceware.org/bugzilla/show_bug.cgi?id=21609
--- Comment #5 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "GNU C Library master sources".
The branch, hjl/pr21609/master has been created
at ed9e8b00cd277979c6368467f93947e45eb8fc30 (commit)
- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=ed9e8b00cd277979c6368467f93947e45eb8fc30
commit ed9e8b00cd277979c6368467f93947e45eb8fc30
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Wed Jul 5 04:46:45 2017 -0700
x86-64: Redirect __tls_get_addr to ___tls_get_addr
On x86-64, __tls_get_addr realigns stack to support GCC older than GCC
4.9.4:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58066
___tls_get_addr is the alternative x86-64 runtime interface to TLS with
aligned stack. If linker treats ___tls_get_addr just like __tls_get_addr
and the weakref assembly directive is extended to redirect __tls_get_addr
to ___tls_get_addr, we can replace reference to __tls_get_addr with
___tls_get_addr if GCC aligns stack for __tls_get_addr, but doesn't
support ___tls_get_addr.
* sysdeps/x86_64/Makefile (+cflags): New. Add
-include $(..)sysdeps/x86_64/tls_get_addr.h if __tls_get_addr
can be redireted to ___tls_get_addr.
* sysdeps/x86_64/configure.ac: Check if GCC supports
___tls_get_addr. If not, check if __tls_get_addr to
___tls_get_addr redirection works.
* sysdeps/x86_64/configure: Regenerated.
* sysdeps/x86_64/tls_get_addr.h: New file.
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=639d0d5203cc112dc775d030ad794217a8d34025
commit 639d0d5203cc112dc775d030ad794217a8d34025
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Tue Jul 4 09:24:09 2017 -0700
x86-64: Export ___tls_get_addr
On x86-64, __tls_get_addr is changed to realign stack to support GCC
older than GCC 4.9.4:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58066
This patch exports ___tls_get_addr as the alternative x86-64 runtime
interface to TLS with aligned stack.
This requires linker support for TLS optimization with ___tls_get_addr.
GCC 4.9.4 and newer can generate call to ___tls_get_addr, instead of
__tls_get_addr. We can use the weakref assembly directive to redirect
__tls_get_addr to ___tls_get_addr if linker supports ___tls_get_addr and
GCC doesn't.
* sysdeps/unix/sysv/linux/x86_64/64/ld.abilist: Add GLIBC_2.26
and ___tls_get_addr.
* sysdeps/unix/sysv/linux/x86_64/x32/ld.abilist: Likewise.
* sysdeps/x86_64/Versions: Export ___tls_get_addr in GLIBC_2.26.
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=08659292af38dffbbec9f07103708f8b5ea48e4c
commit 08659292af38dffbbec9f07103708f8b5ea48e4c
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Mon Jul 3 13:16:57 2017 -0700
x86-64: Align the stack in __tls_get_addr [BZ #21609]
This change forces realignment of the stack pointer in __tls_get_addr, so
that binaries compiled by GCCs older than GCC 4.9:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58066
continue to work even if vector instructions are used in glibc which
require the ABI stack realignment.
__tls_get_addr_slow is added to handle the slow paths in the default
implementation of__tls_get_addr in elf/dl-tls.c. The new __tls_get_addr
calls __tls_get_addr_slow after realigning the stack. Internal calls
within ld.so go directly to the default implementation of __tls_get_addr
because they do not need stack realignment.
2017-07-04 Florian Weimer <fweimer@redhat.com>
H.J. Lu <hongjiu.lu@intel.com>
[BZ #21609]
* sysdeps/x86_64/Makefile (sysdep-dl-routines): Add tls_get_addr.
(gen-as-const-headers): Add rtld-offsets.sym.
* sysdeps/x86_64/dl-tls.c: New file.
* sysdeps/x86_64/rtld-offsets.sym: Likwise.
* sysdeps/x86_64/tls_get_addr.S: Likewise.
* sysdeps/x86_64/dl-tls.h: Add multiple inclusion guards.
* sysdeps/x86_64/tlsdesc.sym (TI_MODULE_OFFSET): New.
(TI_OFFSET_OFFSET): Likwise.
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