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| author | Philipp Rudo <prudo@linux.ibm.com> | 2018-06-26 13:24:30 +0300 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2018-07-06 09:47:48 +0300 |
| commit | ad03b821fbc30395b72af438f5bb41676a5f891d (patch) | |
| tree | 3d57429962224695fd11b89c0f49dce87d3b2015 /arch/s390/purgatory | |
| parent | ad5728ce21398926a1215ebb38570113fa8edd99 (diff) | |
| download | linux-ad03b821fbc30395b72af438f5bb41676a5f891d.tar.xz | |
s390/purgatory: Fix crash with expoline enabled
When the kernel is built with CONFIG_EXPOLINE=y and a compiler with
indirect branch mitigation enabled the purgatory crashes. The reason for
that is that the macros defined for expoline are used in mem.S. These
macros define new sections (.text.__s390x_indirect_*) which are marked
executable. Due to the missing linker script those sections are linked to
address 0, just as the .text section. In combination with the entry point
also being at address 0 this causes the purgatory load code
(kernel/kexec_file.c: kexec_purgatory_setup_sechdrs) to update the entry
point twice. Thus the old kernel jumps to some 'random' address causing the
crash.
To fix this turn off expolines for the purgatory. There is no problem with
this in this case due to the fact that the purgatory only runs once and the
tlb is purged (diag 308) in the end.
Fixes: 840798a1f5299 ("s390/kexec_file: Add purgatory")
Cc: <stable@vger.kernel.org> # 4.17
Signed-off-by: Philipp Rudo <prudo@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/purgatory')
| -rw-r--r-- | arch/s390/purgatory/Makefile | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/s390/purgatory/Makefile b/arch/s390/purgatory/Makefile index 1ace023cbdce..704e0f3c244a 100644 --- a/arch/s390/purgatory/Makefile +++ b/arch/s390/purgatory/Makefile @@ -23,6 +23,7 @@ KBUILD_CFLAGS += -Wno-pointer-sign -Wno-sign-compare KBUILD_CFLAGS += -fno-zero-initialized-in-bss -fno-builtin -ffreestanding KBUILD_CFLAGS += -c -MD -Os -m64 -msoft-float KBUILD_CFLAGS += $(call cc-option,-fno-PIE) +KBUILD_AFLAGS := $(filter-out -DCC_USING_EXPOLINE,$(KBUILD_AFLAGS)) $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE $(call if_changed,ld) |