From df103c09bc2f549d36ba6313a69c18fc003ef1ee Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Wed, 12 Jan 2022 17:50:14 +0100 Subject: [PATCH] target/s390x: Fix cc_calc_sla_64() missing overflows An overflow occurs for SLAG when at least one shifted bit is not equal to sign bit. Therefore, we need to check that `shift + 1` bits are neither all 0s nor all 1s. The current code checks only `shift` bits, missing some overflows. Fixes: cbe24bfa91d2 ("target-s390: Convert SHIFT, ROTATE SINGLE") Co-developed-by: David Hildenbrand Signed-off-by: Ilya Leoshkevich Reviewed-by: David Hildenbrand Message-Id: <20220112165016.226996-4-iii@linux.ibm.com> Signed-off-by: Thomas Huth --- target/s390x/tcg/cc_helper.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/target/s390x/tcg/cc_helper.c b/target/s390x/tcg/cc_helper.c index c2c96c3a3c..c9b7b0e8c6 100644 --- a/target/s390x/tcg/cc_helper.c +++ b/target/s390x/tcg/cc_helper.c @@ -297,7 +297,7 @@ static uint32_t cc_calc_sla_32(uint32_t src, int shift) static uint32_t cc_calc_sla_64(uint64_t src, int shift) { - uint64_t mask = ((1ULL << shift) - 1ULL) << (64 - shift); + uint64_t mask = -1ULL << (63 - shift); uint64_t sign = 1ULL << 63; uint64_t match; int64_t r;