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authorH.J. Lu <hjl.tools@gmail.com>2017-07-06 04:43:06 -0700
committerH.J. Lu <hjl.tools@gmail.com>2017-07-06 04:43:20 -0700
commit031e519c95c069abe4e4c7c59e2b4b67efccdee5 (patch)
tree9d30174961011616431c092d2ba827ce5555944d /sysdeps/x86_64/dl-tls.h
parent0cae0b1a281be45280e12e668434ef2f183edfda (diff)
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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.

	[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.
Diffstat (limited to 'sysdeps/x86_64/dl-tls.h')
-rw-r--r--sysdeps/x86_64/dl-tls.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/sysdeps/x86_64/dl-tls.h b/sysdeps/x86_64/dl-tls.h
index 4a59d2a924..c2fb56c0a1 100644
--- a/sysdeps/x86_64/dl-tls.h
+++ b/sysdeps/x86_64/dl-tls.h
@@ -16,6 +16,9 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+#ifndef _X86_64_DL_TLS_H
+#define _X86_64_DL_TLS_H
+
 #include <stdint.h>
 
 /* Type used for the representation of TLS information in the GOT.  */
@@ -27,3 +30,5 @@ typedef struct dl_tls_index
 
 
 extern void *__tls_get_addr (tls_index *ti);
+
+#endif /* _X86_64_DL_TLS_H */