From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Mon, 6 Jul 2015 15:58:19 +0000 (+0200)
Subject: s390/sclp: clear upper register halves in _sclp_print_early
X-Git-Tag: v3.2.71~36
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=436bd506eaab4da2edf986306135ce3964eecf36;p=pandora-kernel.git

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: Ben Hutchings <ben@decadent.org.uk>
---

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