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authorChristian Borntraeger <borntraeger@de.ibm.com>2015-09-28 22:47:42 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2015-09-29 14:45:10 +0200
commitadc0b7fbf6fe9967505c0254d9535ec7288186ae (patch)
tree3ec22eda5f75d641e016d5205e26912773320748 /arch
parent22be9cd9f22a4b2acc5fe6666ca23206ebe4d495 (diff)
downloadlinux-adc0b7fbf6fe9967505c0254d9535ec7288186ae.tar.gz
s390/boot/decompression: disable floating point in decompressor
my gcc 5.1 used an ldgr instruction with a register != 0,2,4,6 for spilling/filling into a floating point register in our decompressor. This will cause an AFP-register data exception as the decompressor did not setup the additional floating point registers via cr0. That causes a program check loop that looked like a hang with one "Uncompressing Linux... " message (directly booted via kvm) or a loop of "Uncompressing Linux... " messages (when booted via zipl boot loader). The offending code in my build was 48e400: e3 c0 af ff ff 71 lay %r12,-1(%r10) -->48e406: b3 c1 00 1c ldgr %f1,%r12 48e40a: ec 6c 01 22 02 7f clij %r6,2,12,0x48e64e but gcc could do spilling into an fpr at any function. We can simply disable floating point support at that early stage. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: stable@vger.kernel.org
Diffstat (limited to 'arch')
-rw-r--r--arch/s390/boot/compressed/Makefile2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/s390/boot/compressed/Makefile b/arch/s390/boot/compressed/Makefile
index d4788111c161..fac6ac9790fa 100644
--- a/arch/s390/boot/compressed/Makefile
+++ b/arch/s390/boot/compressed/Makefile
@@ -10,7 +10,7 @@ targets += misc.o piggy.o sizes.h head.o
KBUILD_CFLAGS := -m64 -D__KERNEL__ $(LINUX_INCLUDE) -O2
KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
-KBUILD_CFLAGS += $(cflags-y) -fno-delete-null-pointer-checks
+KBUILD_CFLAGS += $(cflags-y) -fno-delete-null-pointer-checks -msoft-float
KBUILD_CFLAGS += $(call cc-option,-mpacked-stack)
KBUILD_CFLAGS += $(call cc-option,-ffreestanding)