Merge remote-tracking branch 'remotes/vivier/tags/m68k-for-5.0-pull-request' into staging

Fix m68k single-stepping with remote gdb

# gpg: Signature made Tue 21 Jan 2020 12:21:12 GMT
# gpg:                using RSA key CD2F75DDC8E3A4DC2E4F5173F30C38BD3F2FBE3C
# gpg:                issuer "laurent@vivier.eu"
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>" [full]
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>" [full]
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>" [full]
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier/tags/m68k-for-5.0-pull-request:
  m68k: Fix regression causing Single-Step via GDB/RSP to not single step

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 27 insertions, 15 deletions

diff --git a/target/m68k/translate.c b/target/m68k/translate.c
index 31b743717e..0f80888203 100644
--- a/target/m68k/translate.c
+++ b/target/m68k/translate.c
@@ -289,16 +289,21 @@ static void gen_jmp(DisasContext *s, TCGv dest)
     s->base.is_jmp = DISAS_JUMP;
 }
 
-static void gen_exception(DisasContext *s, uint32_t dest, int nr)
+static void gen_raise_exception(int nr)
 {
     TCGv_i32 tmp;
 
-    update_cc_op(s);
-    tcg_gen_movi_i32(QREG_PC, dest);
-
     tmp = tcg_const_i32(nr);
     gen_helper_raise_exception(cpu_env, tmp);
     tcg_temp_free_i32(tmp);
+}
+
+static void gen_exception(DisasContext *s, uint32_t dest, int nr)
+{
+    update_cc_op(s);
+    tcg_gen_movi_i32(QREG_PC, dest);
+
+    gen_raise_exception(nr);
 
     s->base.is_jmp = DISAS_NORETURN;
 }
@@ -6198,29 +6203,36 @@ static void m68k_tr_tb_stop(DisasContextBase *dcbase, CPUState *cpu)
 {
     DisasContext *dc = container_of(dcbase, DisasContext, base);
 
-    if (dc->base.is_jmp == DISAS_NORETURN) {
-        return;
-    }
-    if (dc->base.singlestep_enabled) {
-        gen_helper_raise_exception(cpu_env, tcg_const_i32(EXCP_DEBUG));
-        return;
-    }
-
     switch (dc->base.is_jmp) {
+    case DISAS_NORETURN:
+        break;
     case DISAS_TOO_MANY:
         update_cc_op(dc);
-        gen_jmp_tb(dc, 0, dc->pc);
+        if (dc->base.singlestep_enabled) {
+            tcg_gen_movi_i32(QREG_PC, dc->pc);
+            gen_raise_exception(EXCP_DEBUG);
+        } else {
+            gen_jmp_tb(dc, 0, dc->pc);
+        }
         break;
     case DISAS_JUMP:
         /* We updated CC_OP and PC in gen_jmp/gen_jmp_im.  */
-        tcg_gen_lookup_and_goto_ptr();
+        if (dc->base.singlestep_enabled) {
+            gen_raise_exception(EXCP_DEBUG);
+        } else {
+            tcg_gen_lookup_and_goto_ptr();
+        }
         break;
     case DISAS_EXIT:
         /*
          * We updated CC_OP and PC in gen_exit_tb, but also modified
          * other state that may require returning to the main loop.
          */
-        tcg_gen_exit_tb(NULL, 0);
+        if (dc->base.singlestep_enabled) {
+            gen_raise_exception(EXCP_DEBUG);
+        } else {
+            tcg_gen_exit_tb(NULL, 0);
+        }
         break;
     default:
         g_assert_not_reached();