GNU C Library master sources branch master updated. glibc-2.23-572-g1f16923

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http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=1f16923552ec25f17d8624afcdf382591fe5733e

commit 1f16923552ec25f17d8624afcdf382591fe5733e
Author: Stefan Liebler <stli@linux.vnet.ibm.com>
Date:   Wed Jul 20 08:29:43 2016 +0200

    S390: Do not clobber r13 with memcpy on 31bit with copies >1MB.
    
    If the default memcpy variant is called with a length of >1MB on 31bit,
    r13 is clobbered as the algorithm is switching to mvcle. The mvcle code
    returns without restoring r13. All other cases are restoring r13.
    
    If memcpy is called from outside libc the ifunc resolver will only select
    this variant if running on machines older than z10.
    Otherwise or if memcpy is called from inside libc, this default memcpy
    variant is called.
    The testcase timezone/tst-tzset is triggering this issue in some combinations
    of gcc versions and optimization levels.
    
    This bug was introduced in commit 04bb21ac93e90d7696bcaf8febe2b2dd2d83585a
    and thus is a regression compared to former glibc 2.23 release.
    
    This patch removes the usage of r13 at all. Thus it is not saved and restored.
    The base address for execute-instruction is now stored in r5 which is obtained
    after r5 is not needed anymore as 256byte block counter.
    
    ChangeLog:
    
    	* sysdeps/s390/s390-32/memcpy.S (memcpy): Eliminate the usage
    	of r13 as it is not restored in mvcle case.

diff --git a/ChangeLog b/ChangeLog
index a293999..c5456d8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2016-07-20  Stefan Liebler  <stli@linux.vnet.ibm.com>
+
+	* sysdeps/s390/s390-32/memcpy.S (memcpy): Eliminate the usage
+	of r13 as it is not restored in mvcle case.
+
 2016-07-19  Mike Frysinger  <vapier@gentoo.org>
 
 	* sysdeps/unix/sysv/linux/microblaze/sysdep.h (inline_syscall0):
diff --git a/sysdeps/s390/s390-32/memcpy.S b/sysdeps/s390/s390-32/memcpy.S
index 6be5104..1a8bdbf 100644
--- a/sysdeps/s390/s390-32/memcpy.S
+++ b/sysdeps/s390/s390-32/memcpy.S
@@ -42,20 +42,18 @@ ENTRY(memcpy)
 	.machine "g5"
 	lr      %r1,%r2             # r1: Use as dest ; r2: Return dest
 .L_G5_start:
-	st      %r13,52(%r15)
-	.cfi_offset 13, -44
-	basr    %r13,0
-.L_G5_16:
 	ltr     %r4,%r4
-	je      .L_G5_4
+	je      .L_G5_99
 	ahi     %r4,-1
 	lr      %r5,%r4
 	srl     %r5,8
 	ltr     %r5,%r5
 	jne     .L_G5_13
-	ex      %r4,.L_G5_17-.L_G5_16(%r13)
 .L_G5_4:
-	l       %r13,52(%r15)
+	basr    %r5,0
+.L_G5_16:
+	ex      %r4,.L_G5_17-.L_G5_16(%r5)
+.L_G5_99:
 	br      %r14
 .L_G5_13:
 	chi	%r5,4096            # Switch to mvcle for copies >1MB
@@ -65,7 +63,6 @@ ENTRY(memcpy)
 	la      %r1,256(%r1)
 	la      %r3,256(%r3)
 	brct    %r5,.L_G5_12
-	ex      %r4,.L_G5_17-.L_G5_16(%r13)
 	j       .L_G5_4
 .L_G5_17:
 	mvc     0(1,%r1),0(%r3)

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog                     |    5 +++++
 sysdeps/s390/s390-32/memcpy.S |   13 +++++--------
 2 files changed, 10 insertions(+), 8 deletions(-)


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