+static void cpu_exec_step(CPUState *cpu)
+{
+ CPUClass *cc = CPU_GET_CLASS(cpu);
+ CPUArchState *env = (CPUArchState *)cpu->env_ptr;
+ TranslationBlock *tb;
+ target_ulong cs_base, pc;
+ uint32_t flags;
+
+ cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
+ if (sigsetjmp(cpu->jmp_env, 0) == 0) {
+ mmap_lock();
+ tb_lock();
+ tb = tb_gen_code(cpu, pc, cs_base, flags,
+ 1 | CF_NOCACHE | CF_IGNORE_ICOUNT);
+ tb->orig_tb = NULL;
+ tb_unlock();
+ mmap_unlock();
+
+ cc->cpu_exec_enter(cpu);
+ /* execute the generated code */
+ trace_exec_tb_nocache(tb, pc);
+ cpu_tb_exec(cpu, tb);
+ cc->cpu_exec_exit(cpu);
+
+ tb_lock();
+ tb_phys_invalidate(tb, -1);
+ tb_free(tb);
+ tb_unlock();
+ } else {
+ /* We may have exited due to another problem here, so we need
+ * to reset any tb_locks we may have taken but didn't release.
+ * The mmap_lock is dropped by tb_gen_code if it runs out of
+ * memory.
+ */
+#ifndef CONFIG_SOFTMMU
+ tcg_debug_assert(!have_mmap_lock());
+#endif
+ tb_lock_reset();
+ }
+}
+
+void cpu_exec_step_atomic(CPUState *cpu)
+{
+ start_exclusive();
+
+ /* Since we got here, we know that parallel_cpus must be true. */
+ parallel_cpus = false;
+ cpu_exec_step(cpu);
+ parallel_cpus = true;
+
+ end_exclusive();
+}
+