From 72d8ad67ba6d2fb71b84c884bd9f7e7817e2817d Mon Sep 17 00:00:00 2001
From: Richard Henderson <richard.henderson@linaro.org>
Date: Mon, 20 Aug 2018 19:56:24 -0700
Subject: [PATCH] target/s390x: Skip wout, cout helpers if op helper does not
 return

When op raises an exception, it may not have initialized the output
temps that would be written back by wout or cout.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/s390x/translate.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/target/s390x/translate.c b/target/s390x/translate.c
index 18861cd186..a7bd689337 100644
--- a/target/s390x/translate.c
+++ b/target/s390x/translate.c
@@ -1128,11 +1128,19 @@ struct DisasInsn {
 
     const char *name;
 
+    /* Pre-process arguments before HELP_OP.  */
     void (*help_in1)(DisasContext *, DisasFields *, DisasOps *);
     void (*help_in2)(DisasContext *, DisasFields *, DisasOps *);
     void (*help_prep)(DisasContext *, DisasFields *, DisasOps *);
+
+    /*
+     * Post-process output after HELP_OP.
+     * Note that these are not called if HELP_OP returns DISAS_NORETURN.
+     */
     void (*help_wout)(DisasContext *, DisasFields *, DisasOps *);
     void (*help_cout)(DisasContext *, DisasOps *);
+
+    /* Implement the operation itself.  */
     DisasJumpType (*help_op)(DisasContext *, DisasOps *);
 
     uint64_t data;
@@ -6125,11 +6133,13 @@ static DisasJumpType translate_one(CPUS390XState *env, DisasContext *s)
     if (insn->help_op) {
         ret = insn->help_op(s, &o);
     }
-    if (insn->help_wout) {
-        insn->help_wout(s, &f, &o);
-    }
-    if (insn->help_cout) {
-        insn->help_cout(s, &o);
+    if (ret != DISAS_NORETURN) {
+        if (insn->help_wout) {
+            insn->help_wout(s, &f, &o);
+        }
+        if (insn->help_cout) {
+            insn->help_cout(s, &o);
+        }
     }
 
     /* Free any temporaries created by the helpers.  */
-- 
2.30.2