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[PULL,23/34] s390x/tcg: NC: Fault-safe handling

Message ID 20190919124115.11510-24-cohuck@redhat.com
State New
Headers show
Series [PULL,01/34] s390x/tcg: Reset exception_index to -1 instead of 0 | expand

Commit Message

Cornelia Huck Sept. 19, 2019, 12:41 p.m. UTC 
From: David Hildenbrand <david@redhat.com>

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>
---
 target/s390x/mem_helper.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)
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Patch

diff --git a/target/s390x/mem_helper.c b/target/s390x/mem_helper.c
index a2118a82e3ca..20fc17d44de0 100644
--- a/target/s390x/mem_helper.c
+++ b/target/s390x/mem_helper.c
@@ -323,17 +323,26 @@  static int mmu_idx_from_as(uint8_t as)
 static uint32_t do_helper_nc(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);
+    /* NC 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;
 }