[PATCH/backport for 4.4] s390/cpumf: Fix lpp detection

[PATCH/backport for 4.4] s390/cpumf: Fix lpp detection

[Christian Borntraeger]

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>
---
 arch/s390/kernel/head64.S | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S
index 58b719f..1ad2407 100644
--- a/arch/s390/kernel/head64.S
+++ b/arch/s390/kernel/head64.S
@@ -16,7 +16,7 @@
 
 __HEAD
 ENTRY(startup_continue)
-	tm	__LC_STFL_FAC_LIST+6,0x80	# LPP available ?
+	tm	__LC_STFL_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
-- 
2.5.0

Re: [PATCH/backport for 4.4] s390/cpumf: Fix lpp detection

[Greg KH]

On Wed, Mar 16, 2016 at 11:02:58AM +0100, Christian Borntraeger wrote:
> 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>
> ---
>  arch/s390/kernel/head64.S | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

What is the git commit id of this patch in Linus's tree?

thanks,

greg k-h

Re: [PATCH/backport for 4.4] s390/cpumf: Fix lpp detection

[Christian Borntraeger]

On 03/16/2016 04:15 PM, Greg KH wrote:
> On Wed, Mar 16, 2016 at 11:02:58AM +0100, Christian Borntraeger wrote:
>> 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>
>> ---
>>  arch/s390/kernel/head64.S | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> What is the git commit id of this patch in Linus's tree?
> 
> thanks,
> 
> greg k-h
> 


>From 7a76aa95f6f6682db5629449d763251d1c9f8c4e Mon Sep 17 00:00:00 2001
From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Mon, 29 Feb 2016 15:59:18 +0100
Subject: [PATCH] s390/cpumf: Fix lpp detection

This is the fixup for you mail 
"FAILED: patch "[PATCH] s390/cpumf: Fix lpp detection" failed to apply to 4.4-stable tree"
from 03/12/2016