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[Committed] S/390: Fix optimized mem* routines on 31 bit kernels

Hi,

the attached patch fixes two problems with the optimized mem*
functions on 31 bit kernels.

- The optimized routines contain zarch mode instructions and therefore
  are supposed to be used only for 31 bit code running on a 64 bit
  kernel.  However, assembling these files using the -mzarch option
  makes them depend unconditionally on the highgprs kernel feature.
  So the whole Glibc and everything using its crt files would be
  prevented from being run on a 31 bit kernel although the IFUNC
  resolver at runtime would make sure that the ESA mode variant would
  be used in that case.

  In order to fix this I've added a new s390 dependent pseudo
  (.machinemode) to GAS which allows to enable zarch mode instructions
  without setting the highgprs flag:
  http://sourceware.org/ml/binutils/2012-09/msg00071.html

  The attached patch makes use of this new pseudo. So building 31 bit
  glibc for S/390 currently depends on upstream Binutils.

- Currently the Linux kernel reports having the highgprs feature even
  for 31 bit kernels.  This is a bug which will be fixed soon.  So far
  the Glibc IFUNC resolver on 31 bit (correctly) relies on the fact
  that highgprs is only possible in zarch mode.  With the patch the
  zarch mode flag is checked explicitly as well in order to deal with
  the currently broken kernels.

Bye,

-Andreas-


2012-09-06  Andreas Krebbel  <Andreas.Krebbel@de.ibm.com>

	* sysdeps/s390/s390-32/multiarch/Makefile: Remove -mzarch
	assembler flag.
	* sysdeps/s390/s390-32/multiarch/memcmp.S: Use .machinemode
	zarch_nohighgprs around the zarch optimized routines.
	* sysdeps/s390/s390-32/multiarch/memcpy.S: Likewise.
	* sysdeps/s390/s390-32/multiarch/memset.S: Likewise.
	* sysdeps/s390/s390-32/multiarch/ifunc-resolve.c: Explicitly check
	for zarch.

---
 sysdeps/s390/s390-32/multiarch/Makefile        |    6 ------
 sysdeps/s390/s390-32/multiarch/ifunc-resolve.c |    3 ++-
 sysdeps/s390/s390-32/multiarch/memcmp.S        |    2 ++
 sysdeps/s390/s390-32/multiarch/memcpy.S        |    2 ++
 sysdeps/s390/s390-32/multiarch/memset.S        |    2 ++
 5 files changed, 8 insertions(+), 7 deletions(-)

Index: glibc/sysdeps/s390/s390-32/multiarch/Makefile
===================================================================
--- glibc.orig/sysdeps/s390/s390-32/multiarch/Makefile
+++ glibc/sysdeps/s390/s390-32/multiarch/Makefile
@@ -1,9 +1,3 @@
-ASFLAGS-.o += -Wa,-mzarch
-ASFLAGS-.os += -Wa,-mzarch
-ASFLAGS-.op += -Wa,-mzarch
-ASFLAGS-.og += -Wa,-mzarch
-ASFLAGS-.ob += -Wa,-mzarch
-ASFLAGS-.oS += -Wa,-mzarch
 ifeq ($(subdir),string)
 sysdep_routines += ifunc-resolve memset memcpy memcmp
 endif
Index: glibc/sysdeps/s390/s390-32/multiarch/memcmp.S
===================================================================
--- glibc.orig/sysdeps/s390/s390-32/multiarch/memcmp.S
+++ glibc/sysdeps/s390/s390-32/multiarch/memcmp.S
@@ -31,6 +31,7 @@
 
 ENTRY(memcmp_z196)
 	.machine "z196"
+	.machinemode "zarch_nohighgprs"
         ltr     %r4,%r4
         je      .L_Z196_4
         ahi     %r4,-1
@@ -64,6 +65,7 @@ END(memcmp_z196)
 
 ENTRY(memcmp_z10)
 	.machine "z10"
+	.machinemode "zarch_nohighgprs"
         ltr     %r4,%r4
         je      .L_Z10_4
         ahi     %r4,-1
Index: glibc/sysdeps/s390/s390-32/multiarch/memcpy.S
===================================================================
--- glibc.orig/sysdeps/s390/s390-32/multiarch/memcpy.S
+++ glibc/sysdeps/s390/s390-32/multiarch/memcpy.S
@@ -31,6 +31,7 @@
 
 ENTRY(memcpy_z196)
 	.machine "z196"
+	.machinemode "zarch_nohighgprs"
         llgfr   %r4,%r4
         ltgr    %r4,%r4
         je      .L_Z196_4
@@ -61,6 +62,7 @@ END(memcpy_z196)
 
 ENTRY(memcpy_z10)
 	.machine "z10"
+	.machinemode "zarch_nohighgprs"
         llgfr   %r4,%r4
         cgije   %r4,0,.L_Z10_4
         aghi    %r4,-1
Index: glibc/sysdeps/s390/s390-32/multiarch/memset.S
===================================================================
--- glibc.orig/sysdeps/s390/s390-32/multiarch/memset.S
+++ glibc/sysdeps/s390/s390-32/multiarch/memset.S
@@ -31,6 +31,7 @@
 
 ENTRY(memset_z196)
 	.machine "z196"
+	.machinemode "zarch_nohighgprs"
         llgfr   %r4,%r4
         ltgr    %r4,%r4
         je      .L_Z196_4
@@ -62,6 +63,7 @@ END(memset_z196)
 
 ENTRY(memset_z10)
 	.machine "z10"
+	.machinemode "zarch_nohighgprs"
         llgfr   %r4,%r4
         cgije   %r4,0,.L_Z10_4
         stc     %r3,0(%r2)
Index: glibc/sysdeps/s390/s390-32/multiarch/ifunc-resolve.c
===================================================================
--- glibc.orig/sysdeps/s390/s390-32/multiarch/ifunc-resolve.c
+++ glibc/sysdeps/s390/s390-32/multiarch/ifunc-resolve.c
@@ -41,7 +41,8 @@
   void *resolve_##FUNC (unsigned long int dl_hwcap)			\
   {									\
     if ((dl_hwcap & HWCAP_S390_STFLE)					\
-	&& (dl_hwcap & HWCAP_S390_HIGH_GPRS)) /* Implies zarch */	\
+	&& (dl_hwcap & HWCAP_S390_ZARCH)				\
+	&& (dl_hwcap & HWCAP_S390_HIGH_GPRS))				\
       {									\
 	/* We want just 1 double word to be returned.  */		\
 	register unsigned long reg0 asm("0") = 0;			\
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