s390/xor: Fix xor_xc_5() inline assembly

xor_xc_5() contains a larl 1,2f that is not used by the asm and is not
declared as a clobber. This can corrupt a compiler-allocated value in %r1
and lead to miscompilation. Remove the instruction.

Fixes: 745600ed6965 ("s390/lib: Use exrl instead of ex in xor functions")
Cc: stable@vger.kernel.org
Reviewed-by: Juergen Christ <jchrist@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

diff --git a/arch/s390/lib/xor.c b/arch/s390/lib/xor.c
index 1721b73b780369cbf99f359669b99fc480b88fef..a4d8b51beb95f74da7fe4a88970282a6e2b23816 100644 (file)
--- a/arch/s390/lib/xor.c
+++ b/arch/s390/lib/xor.c
@@ -96,7 +96,6 @@ static void xor_xc_5(unsigned long bytes, unsigned long * __restrict p1,
                     const unsigned long * __restrict p5)
 {
        asm volatile(
-               "       larl    1,2f\n"
                "       aghi    %0,-1\n"
                "       jm      6f\n"
                "       srlg    0,%0,8\n"