[Qemu-arm] [PATCH v2 4/5] target/arm: use DISAS_JUMP for ISB handling

[Alex Bennée]

While an ISB will ensure any raised IRQs happen on the next
instruction it doesn't cause any to get raised by itself. We can
therefor use DISAS_JUMP for ISB instructions and rely on the
exit_request check at the top of each TB to deal with exiting if
needed.

Signed-off-by: Alex Bennée <address@hidden>
---
 target/arm/translate-a64.c |  3 ++-
 target/arm/translate.c     | 13 +++++++++++--
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index 66139b6046..ad46d84efb 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -1393,7 +1393,8 @@ static void handle_sync(DisasContext *s, uint32_t insn,
          * a self-modified code correctly and also to take
          * any pending interrupts immediately.
          */
-        s->is_jmp = DISAS_UPDATE;
+        gen_a64_set_pc_im(s->pc);
+        s->is_jmp = DISAS_JUMP;
         return;
     default:
         unallocated_encoding(s);
diff --git a/target/arm/translate.c b/target/arm/translate.c
index ccc4768b2e..94aa4bbb4d 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -1201,6 +1201,15 @@ static inline void gen_lookup_tb(DisasContext *s)
     s->is_jmp = DISAS_EXIT;
 }
 
+/* End the current block and force a TB lookup. We may chain to the
+ * next TB but exit_req will be immediately checked so we will exit to
+ * the main loop if we need to */
+static inline void gen_jump_tb(DisasContext *s)
+{
+    tcg_gen_movi_i32(cpu_R[15], s->pc & ~1);
+    s->is_jmp = DISAS_JUMP;
+}
+
 static inline void gen_hlt(DisasContext *s, int imm)
 {
     /* HLT. This has two purposes.
@@ -8165,7 +8174,7 @@ static void disas_arm_insn(DisasContext *s, unsigned int 
insn)
                  * self-modifying code correctly and also to take
                  * any pending interrupts immediately.
                  */
-                gen_lookup_tb(s);
+                gen_jump_tb(s);
                 return;
             default:
                 goto illegal_op;
@@ -10558,7 +10567,7 @@ static int disas_thumb2_insn(CPUARMState *env, 
DisasContext *s, uint16_t insn_hw
                              * and also to take any pending interrupts
                              * immediately.
                              */
-                            gen_lookup_tb(s);
+                            gen_jump_tb(s);
                             break;
                         default:
                             goto illegal_op;
-- 
2.13.0