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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2015-07-06 17:58:19 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-08-10 12:21:52 -0700
commit88b7166f0d995edd9884a4641d2a0bca77b52090 (patch)
tree6a9502665305bff6d65d66475a886eed429da4aa /arch
parent5e62f6843f4071e5cbb021c00737ebd0673ebf18 (diff)
s390/sclp: clear upper register halves in _sclp_print_early
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 <schwidefsky@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/s390/kernel/sclp.S4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/s390/kernel/sclp.S b/arch/s390/kernel/sclp.S
index 43c3169ea49c..ada0c07fe1a8 100644
--- 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