From 5b185639c5740998de403415c749ac98e13418fd Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Mon, 30 May 2011 10:49:45 +0200 Subject: s390x: fix cksm instruction The cksm instruction was implemented incorrectly, rendering UDP and TCP checksum calculation wrong, making an emulated s390x Linux guest break in most networking operations. This patch fixes odd end checksum calculation, takes the input register as input for the checksum and optimizes the overflow pieces by a bit. Signed-off-by: Alexander Graf --- target-s390x/op_helper.c | 28 ++++++++-------------------- 1 file changed, 8 insertions(+), 20 deletions(-) (limited to 'target-s390x') diff --git a/target-s390x/op_helper.c b/target-s390x/op_helper.c index 49760a40a2..db03a7971f 100644 --- a/target-s390x/op_helper.c +++ b/target-s390x/op_helper.c @@ -1731,25 +1731,15 @@ void HELPER(sqdbr)(uint32_t f1, uint32_t f2) env->fregs[f1].d = float64_sqrt(env->fregs[f2].d, &env->fpu_status); } -static inline uint64_t cksm_overflow(uint64_t cksm) -{ - if (cksm > 0xffffffffULL) { - cksm &= 0xffffffffULL; - cksm++; - } - return cksm; -} - /* checksum */ void HELPER(cksm)(uint32_t r1, uint32_t r2) { uint64_t src = get_address_31fix(r2); uint64_t src_len = env->regs[(r2 + 1) & 15]; - uint64_t cksm = 0; + uint64_t cksm = (uint32_t)env->regs[r1]; while (src_len >= 4) { cksm += ldl(src); - cksm = cksm_overflow(cksm); /* move to next word */ src_len -= 4; @@ -1760,26 +1750,24 @@ void HELPER(cksm)(uint32_t r1, uint32_t r2) case 0: break; case 1: - cksm += ldub(src); - cksm = cksm_overflow(cksm); + cksm += ldub(src) << 24; break; case 2: - cksm += lduw(src); - cksm = cksm_overflow(cksm); + cksm += lduw(src) << 16; break; case 3: - /* XXX check if this really is correct */ - cksm += lduw(src) << 8; - cksm += ldub(src + 2); - cksm = cksm_overflow(cksm); + cksm += lduw(src) << 16; + cksm += ldub(src + 2) << 8; break; } /* indicate we've processed everything */ + env->regs[r2] = src + src_len; env->regs[(r2 + 1) & 15] = 0; /* store result */ - env->regs[r1] = (env->regs[r1] & 0xffffffff00000000ULL) | (uint32_t)cksm; + env->regs[r1] = (env->regs[r1] & 0xffffffff00000000ULL) | + ((uint32_t)cksm + (cksm >> 32)); } static inline uint32_t cc_calc_ltgt_32(CPUState *env, int32_t src, -- cgit v1.2.3