target/arm: Delay check for magic kernel page

There's nothing magic about the exception that we generate in order
to execute the magic kernel page.  We can and should allow gdb to
set a breakpoint at this location.

Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>

target/arm/translate.c

@@ -11968,17 +11968,6 @@ void gen_intermediate_code(CPUState *cs, TranslationBlock *tb)
                            0);
         num_insns++;
 
-#ifdef CONFIG_USER_ONLY
-        /* Intercept jump to the magic kernel page.  */
-        if (dc->pc >= 0xffff0000) {
-            /* We always get here via a jump, so know we are not in a
-               conditional execution block.  */
-            gen_exception_internal(EXCP_KERNEL_TRAP);
-            dc->is_jmp = DISAS_NORETURN;
-            break;
-        }
-#endif
-
         if (unlikely(!QTAILQ_EMPTY(&cs->breakpoints))) {
             CPUBreakpoint *bp;
             QTAILQ_FOREACH(bp, &cs->breakpoints, entry) {
@@ -12010,6 +11999,17 @@ void gen_intermediate_code(CPUState *cs, TranslationBlock *tb)
             gen_io_start();
         }
 
+#ifdef CONFIG_USER_ONLY
+        /* Intercept jump to the magic kernel page.  */
+        if (dc->pc >= 0xffff0000) {
+            /* We always get here via a jump, so know we are not in a
+               conditional execution block.  */
+            gen_exception_internal(EXCP_KERNEL_TRAP);
+            dc->is_jmp = DISAS_NORETURN;
+            break;
+        }
+#endif
+
         if (dc->ss_active && !dc->pstate_ss) {
             /* Singlestep state is Active-pending.
              * If we're in this state at the start of a TB then either