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[4/4,Xenial,SRU,V2] s390/cpumf: Fix lpp detection

Message ID 1460185965-9497-4-git-send-email-tim.gardner@canonical.com
State New
Headers show

Commit Message

Tim Gardner April 9, 2016, 7:12 a.m. UTC 
From: Christian Borntraeger <borntraeger@de.ibm.com>

BugLink: http://bugs.launchpad.net/bugs/1555344

we have to check bit 40 of the facility list before issuing LPP
and not bit 48. Otherwise a guest running on a system with
"The decimal-floating-point zoned-conversion facility" and without
the "The set-program-parameters facility" might crash on an lpp
instruction.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: stable@vger.kernel.org # v4.4+
Fixes: e22cf8ca6f75 ("s390/cpumf: rework program parameter setting to detect guest samples")
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
(cherry picked from commit 7a76aa95f6f6682db5629449d763251d1c9f8c4e)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
---
 arch/s390/kernel/head64.S | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S
index c5febe8..03c2b46 100644
--- a/arch/s390/kernel/head64.S
+++ b/arch/s390/kernel/head64.S
@@ -16,7 +16,7 @@ 
 
 __HEAD
 ENTRY(startup_continue)
-	tm	__LC_STFLE_FAC_LIST+6,0x80	# LPP available ?
+	tm	__LC_STFLE_FAC_LIST+5,0x80	# LPP available ?
 	jz	0f
 	xc	__LC_LPP+1(7,0),__LC_LPP+1	# clear lpp and current_pid
 	mvi	__LC_LPP,0x80			#   and set LPP_MAGIC