[PATCH 4.1 027/123] s390/process: fix sfpc inline assembly

From: Greg Kroah-Hartman
Date: Sat Aug 08 2015 - 18:31:54 EST

4.1-stable review patch. If anyone has any objections, please let me know.


From: Heiko Carstens <heiko.carstens@xxxxxxxxxx>

commit e47994dd44bcb4a77b4152bd0eada585934703c0 upstream.

The sfpc inline assembly within execve_tail() may incorrectly set bits
28-31 of the sfpc instruction to a value which is not zero.
These bits however are currently unused and therefore should be zero
so we won't get surprised if these bits will be used in the future.

Therefore remove the second operand from the inline assembly.

Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

arch/s390/kernel/process.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -163,7 +163,7 @@ int copy_thread(unsigned long clone_flag
asmlinkage void execve_tail(void)
current->thread.fp_regs.fpc = 0;
- asm volatile("sfpc %0,%0" : : "d" (0));
+ asm volatile("sfpc %0" : : "d" (0));


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