Commit b29c5093 authored by Heiko Carstens's avatar Heiko Carstens Committed by Vasily Gorbik
Browse files

s390/vtime: fix inline assembly clobber list 



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: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent fe8344a0

arch/s390/kernel/vtime.c

+2 −1
Original line number Diff line number Diff line
@@ -136,7 +136,8 @@ static int do_account_vtime(struct task_struct *tsk) 
		"	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;