s390x/tcg: ASI/ASGI/ALSI/ALSGI are atomic with Interlocked-acccess facility 1

The semantics of ASI/ASGI/ALSI/ALSGI changed. Let's implement them just
like LOAD AND ADD, so they are atomic. Emulate old behavior.

This fixes random crashes when booting a Linux kernel compiled for
z196+ with SMP + MTTCG.

Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20171208160207.26494-7-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/target/s390x/translate.c b/target/s390x/translate.c
index 08c1ace..7ab8e85 100644
--- a/target/s390x/translate.c
+++ b/target/s390x/translate.c
@@ -1364,6 +1364,27 @@ static ExitStatus op_addc(DisasContext *s, DisasOps *o)
     return NO_EXIT;
 }
 
+static ExitStatus op_asi(DisasContext *s, DisasOps *o)
+{
+    o->in1 = tcg_temp_new_i64();
+
+    if (!s390_has_feat(S390_FEAT_STFLE_45)) {
+        tcg_gen_qemu_ld_tl(o->in1, o->addr1, get_mem_index(s), s->insn->data);
+    } else {
+        /* Perform the atomic addition in memory. */
+        tcg_gen_atomic_fetch_add_i64(o->in1, o->addr1, o->in2, get_mem_index(s),
+                                     s->insn->data);
+    }
+
+    /* Recompute also for atomic case: needed for setting CC. */
+    tcg_gen_add_i64(o->out, o->in1, o->in2);
+
+    if (!s390_has_feat(S390_FEAT_STFLE_45)) {
+        tcg_gen_qemu_st_tl(o->out, o->addr1, get_mem_index(s), s->insn->data);
+    }
+    return NO_EXIT;
+}
+
 static ExitStatus op_aeb(DisasContext *s, DisasOps *o)
 {
     gen_helper_aeb(o->out, cpu_env, o->in1, o->in2);