diff mbox series

[5.11,732/775] s390/vtime: fix inline assembly clobber list

Message ID 20210301161237.512333324@linuxfoundation.org
State Superseded
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman March 1, 2021, 4:15 p.m. UTC 
From: Heiko Carstens <hca@linux.ibm.com>

commit b29c5093820d333eef22f58cd04ec0d089059c39 upstream.

The stck/stckf instruction used within the inline assembly within
do_account_vtime() changes the condition code. This is not reflected
with the clobber list, and therefore might result in incorrect code
generation.

It seems unlikely that the compiler could generate incorrect code
considering the surrounding C code, but it must still be fixed.

Cc: <stable@vger.kernel.org>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/s390/kernel/vtime.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff mbox series

Patch

--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -136,7 +136,8 @@  static int do_account_vtime(struct task_
 		"	stck	%1"	/* Store current tod clock value */
 #endif
 		: "=Q" (S390_lowcore.last_update_timer),
-		  "=Q" (S390_lowcore.last_update_clock));
+		  "=Q" (S390_lowcore.last_update_clock)
+		: : "cc");
 	clock = S390_lowcore.last_update_clock - clock;
 	timer -= S390_lowcore.last_update_timer;