s390x/tcg: OC: Fault-safe handling

We can process a maximum of 256 bytes, crossing two pages.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
This commit is contained in:
David Hildenbrand 2019-09-04 16:31:15 +02:00
parent b8e7b2fe1d
commit 8c4a732076
1 changed files with 13 additions and 4 deletions

View File

@ -389,17 +389,26 @@ uint32_t HELPER(xc)(CPUS390XState *env, uint32_t l, uint64_t dest,
static uint32_t do_helper_oc(CPUS390XState *env, uint32_t l, uint64_t dest,
uint64_t src, uintptr_t ra)
{
const int mmu_idx = cpu_mmu_index(env, false);
S390Access srca1, srca2, desta;
uint32_t i;
uint8_t c = 0;
HELPER_LOG("%s l %d dest %" PRIx64 " src %" PRIx64 "\n",
__func__, l, dest, src);
for (i = 0; i <= l; i++) {
uint8_t x = cpu_ldub_data_ra(env, src + i, ra);
x |= cpu_ldub_data_ra(env, dest + i, ra);
/* OC always processes one more byte than specified - maximum is 256 */
l++;
srca1 = access_prepare(env, src, l, MMU_DATA_LOAD, mmu_idx, ra);
srca2 = access_prepare(env, dest, l, MMU_DATA_LOAD, mmu_idx, ra);
desta = access_prepare(env, dest, l, MMU_DATA_STORE, mmu_idx, ra);
for (i = 0; i < l; i++) {
const uint8_t x = access_get_byte(env, &srca1, i, ra) |
access_get_byte(env, &srca2, i, ra);
c |= x;
cpu_stb_data_ra(env, dest + i, x, ra);
access_set_byte(env, &desta, i, x, ra);
}
return c != 0;
}