1 files changed, 82 insertions, 0 deletions
diff --git a/accel/tcg/cpu-exec-common.c b/accel/tcg/cpu-exec-common.c
new file mode 100644
index 0000000000..e81da276bb
--- /dev/null
+++ b/accel/tcg/cpu-exec-common.c
@@ -0,0 +1,82 @@
+/*
+ *  emulator main execution loop
+ *
+ *  Copyright (c) 2003-2005 Fabrice Bellard
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "cpu.h"
+#include "sysemu/cpus.h"
+#include "exec/exec-all.h"
+#include "exec/memory-internal.h"
+
+/* exit the current TB, but without causing any exception to be raised */
+void cpu_loop_exit_noexc(CPUState *cpu)
+{
+    /* XXX: restore cpu registers saved in host registers */
+
+    cpu->exception_index = -1;
+    siglongjmp(cpu->jmp_env, 1);
+}
+
+#if defined(CONFIG_SOFTMMU)
+void cpu_reloading_memory_map(void)
+{
+    if (qemu_in_vcpu_thread() && current_cpu->running) {
+        /* The guest can in theory prolong the RCU critical section as long
+         * as it feels like. The major problem with this is that because it
+         * can do multiple reconfigurations of the memory map within the
+         * critical section, we could potentially accumulate an unbounded
+         * collection of memory data structures awaiting reclamation.
+         *
+         * Because the only thing we're currently protecting with RCU is the
+         * memory data structures, it's sufficient to break the critical section
+         * in this callback, which we know will get called every time the
+         * memory map is rearranged.
+         *
+         * (If we add anything else in the system that uses RCU to protect
+         * its data structures, we will need to implement some other mechanism
+         * to force TCG CPUs to exit the critical section, at which point this
+         * part of this callback might become unnecessary.)
+         *
+         * This pair matches cpu_exec's rcu_read_lock()/rcu_read_unlock(), which
+         * only protects cpu->as->dispatch. Since we know our caller is about
+         * to reload it, it's safe to split the critical section.
+         */
+        rcu_read_unlock();
+        rcu_read_lock();
+    }
+}
+#endif
+
+void cpu_loop_exit(CPUState *cpu)
+{
+    siglongjmp(cpu->jmp_env, 1);
+}
+
+void cpu_loop_exit_restore(CPUState *cpu, uintptr_t pc)
+{
+    if (pc) {
+        cpu_restore_state(cpu, pc);
+    }
+    siglongjmp(cpu->jmp_env, 1);
+}
+
+void cpu_loop_exit_atomic(CPUState *cpu, uintptr_t pc)
+{
+    cpu->exception_index = EXCP_ATOMIC;
+    cpu_loop_exit_restore(cpu, pc);
+}