[PATCH 2/3] cpu: Introduce EXCLUSIVE_GUARD()

[Ilya Leoshkevich <iii@linux.ibm.com>]

Add a macro that produces a start_exclusive() / end_exclusive() pair.
Useful to guarantee an exit from an exclusive section in large
functions.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 include/hw/core/cpu.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index c3ca0babcb3..a7d9d6e2b8c 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -1063,6 +1063,17 @@ void start_exclusive(void);
  */
 void end_exclusive(void);
 
+static inline void exclusive_unlock_guard(int *exclusive_guard G_GNUC_UNUSED)
+{
+    end_exclusive();
+}
+
+#define EXCLUSIVE_GUARD()                                      \
+    int glue(exclusive_guard, __COUNTER__)                     \
+            G_GNUC_UNUSED                                      \
+            __attribute__((cleanup(exclusive_unlock_guard))) = \
+        (start_exclusive(), 0);
+
 /**
  * qemu_init_vcpu:
  * @cpu: The vCPU to initialize.
-- 
2.47.1