From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Thu, 21 Jun 2018 14:49:38 +0200
Subject: s390: Correct register corruption in critical section cleanup
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Git-commit: 891f6a726cacbb87e5b06076693ffab53bd378d7
Patch-mainline: v4.18-rc4
References: git-fixes 6dd85fbb87
In the critical section cleanup we must not mess with r1. For march=z9
or older, larl + ex (instead of exrl) are used with r1 as a temporary
register. This can clobber r1 in several interrupt handlers. Fix this by
using r11 as a temp register. r11 is being saved by all callers of
cleanup_critical.
Fixes: 6dd85fbb87 ("s390: move expoline assembler macros to a header")
Cc: stable@vger.kernel.org #v4.16
Reported-by: Oliver Kurz <okurz@suse.com>
Reported-by: Petr Tesařík <ptesarik@suse.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
arch/s390/kernel/entry.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index f03402efab4b..3891805bfcdd 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -1265,7 +1265,7 @@ cleanup_critical:
jl 0f
clg %r9,BASED(.Lcleanup_table+104) # .Lload_fpu_regs_end
jl .Lcleanup_load_fpu_regs
-0: BR_EX %r14
+0: BR_EX %r14,%r11
.align 8
.Lcleanup_table:
@@ -1301,7 +1301,7 @@ cleanup_critical:
ni __SIE_PROG0C+3(%r9),0xfe # no longer in SIE
lctlg %c1,%c1,__LC_USER_ASCE # load primary asce
larl %r9,sie_exit # skip forward to sie_exit
- BR_EX %r14
+ BR_EX %r14,%r11
#endif
.Lcleanup_system_call: