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

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.

1 files changed, 4 insertions, 1 deletions

diff --git a/sysdeps/s390/s390-32/multiarch/memcpy-s390.S b/sysdeps/s390/s390-32/multiarch/memcpy-s390.S
index 4e30cdf6c6..92ffaea5ed 100644
--- a/sysdeps/s390/s390-32/multiarch/memcpy-s390.S
+++ b/sysdeps/s390/s390-32/multiarch/memcpy-s390.S
@@ -92,7 +92,10 @@ END(__memcpy_z10)
 
 #include "../memcpy.S"
 
-#if !defined SHARED || !IS_IN (libc)
+#if defined SHARED && IS_IN (libc)
+.globl   __GI_memcpy
+.set     __GI_memcpy,__memcpy_default
+#else
 .globl   memcpy
 .set     memcpy,__memcpy_default
 #endif