This is a note to let you know that I've just added the patch titled
s390/sclp: clear upper register halves in _sclp_print_early
to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
s390-sclp-clear-upper-register-halves-in-_sclp_print_early.patch
and it can be found in the queue-4.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From f9c87a6f46d508eae0d9ae640be98d50f237f827 Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <[email protected]>
Date: Mon, 6 Jul 2015 17:58:19 +0200
Subject: s390/sclp: clear upper register halves in _sclp_print_early
From: Martin Schwidefsky <[email protected]>
commit f9c87a6f46d508eae0d9ae640be98d50f237f827 upstream.
If the kernel is compiled with gcc 5.1 and the XZ compression option
the decompress_kernel function calls _sclp_print_early in 64-bit mode
while the content of the upper register half of %r6 is non-zero.
This causes a specification exception on the servc instruction in
_sclp_servc.
The _sclp_print_early function saves and restores the upper registers
halves but it fails to clear them for the 31-bit code of the mini sclp
driver.
Signed-off-by: Martin Schwidefsky <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/s390/kernel/sclp.S | 4 ++++
1 file changed, 4 insertions(+)
--- a/arch/s390/kernel/sclp.S
+++ b/arch/s390/kernel/sclp.S
@@ -270,6 +270,8 @@ ENTRY(_sclp_print_early)
jno .Lesa2
ahi %r15,-80
stmh %r6,%r15,96(%r15) # store upper register halves
+ basr %r13,0
+ lmh %r0,%r15,.Lzeroes-.(%r13) # clear upper register halves
.Lesa2:
lr %r10,%r2 # save string pointer
lhi %r2,0
@@ -291,6 +293,8 @@ ENTRY(_sclp_print_early)
.Lesa3:
lm %r6,%r15,120(%r15) # restore registers
br %r14
+.Lzeroes:
+ .fill 64,4,0
.LwritedataS4:
.long 0x00760005 # SCLP command for write data
Patches currently in stable-queue which might be from [email protected] are
queue-4.1/s390-cachinfo-add-missing-facility-check-to-init_cache_level.patch
queue-4.1/s390-process-fix-sfpc-inline-assembly.patch
queue-4.1/s390-sclp-clear-upper-register-halves-in-_sclp_print_early.patch
queue-4.1/s390-nmi-fix-vector-register-corruption.patch
queue-4.1/s390-bpf-clear-correct-bpf-accumulator-register.patch
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