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S390: Do not call memcpy, memcmp, memset within libc.so via ifunc-plt.

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On s390, the memcpy, memcmp, memset functions are IFUNC symbols,
which are created with s390_libc_ifunc-macro.
This macro creates a __GI_ symbol which is set to the
ifunced symbol. Thus calls within libc.so to e.g. memcpy
result in a call to *ABS*+0x954c0@plt stub and afterwards
to the resolved memcpy-ifunc-variant.

This patch sets the __GI_ symbol to the default-ifunc-variant
to avoid the plt call. The __GI_ symbols are now created at the
default variant of ifunced function.

ChangeLog:

	* sysdeps/s390/multiarch/ifunc-resolve.h (s390_libc_ifunc):
	Remove __GI_ symbol.
	* sysdeps/s390/s390-32/multiarch/memcmp-s390.S: Add __GI_memcmp symbol.
	* sysdeps/s390/s390-64/multiarch/memcmp-s390x.S: Likewise.
	* sysdeps/s390/s390-32/multiarch/memcpy-s390.S: Add __GI_memcpy symbol.
	* sysdeps/s390/s390-64/multiarch/memcpy-s390x.S: Likewise.
	* sysdeps/s390/s390-32/multiarch/memset-s390.S: Add __GI_memset symbol.
	* sysdeps/s390/s390-64/multiarch/memset-s390x.S: Likewise.
This commit is contained in:
Stefan Liebler
2016-05-24 10:39:13 +02:00
parent 074b0f27d9
commit 7165583255
8 changed files with 32 additions and 5 deletions
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4
sysdeps/s390/multiarch/ifunc-resolve.h
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@@ -44,9 +44,7 @@
#define s390_libc_ifunc(FUNC) \
__asm__ (".globl " #FUNC "\n\t" \
".type " #FUNC ",@gnu_indirect_function\n\t" \
".set " #FUNC ",__resolve_" #FUNC "\n\t" \
".globl __GI_" #FUNC "\n\t" \
".set __GI_" #FUNC "," #FUNC "\n"); \
".set " #FUNC ",__resolve_" #FUNC "\n\t"); \
\
/* Make the declarations of the optimized functions hidden in order
to prevent GOT slots being generated for them. */ \