urcu-pointer: create specific objects and headers to deal with RCU pointers

[urcu.git] / urcu / system.h

diff --git a/urcu/system.h b/urcu/system.h
new file mode 100644 (file)
index 0000000..e36a13b
--- /dev/null
+++ b/urcu/system.h
@@ -0,0 +1,54 @@
+#ifndef _URCU_SYSTEM_H
+#define _URCU_SYSTEM_H
+
+/*
+ * system.h
+ *
+ * System definitions.
+ *
+ * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
+ * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program
+ * for any purpose,  provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is granted,
+ * provided the above notices are retained, and a notice that the code was
+ * modified is included with the above copyright notice.
+ */
+
+#include <urcu/compiler.h>
+#include <urcu/arch.h>
+
+/*
+ * Identify a shared load. A smp_rmc() or smp_mc() should come before the load.
+ */
+#define _LOAD_SHARED(p)               ACCESS_ONCE(p)
+
+/*
+ * Load a data from shared memory, doing a cache flush if required.
+ */
+#define LOAD_SHARED(p)                 \
+       ({                              \
+               smp_rmc();              \
+               _LOAD_SHARED(p);        \
+       })
+
+/*
+ * Identify a shared store. A smp_wmc() or smp_mc() should follow the store.
+ */
+#define _STORE_SHARED(x, v)    ({ ACCESS_ONCE(x) = (v); })
+
+/*
+ * Store v into x, where x is located in shared memory. Performs the required
+ * cache flush after writing. Returns v.
+ */
+#define STORE_SHARED(x, v)             \
+       ({                              \
+               _STORE_SHARED(x, v);    \
+               smp_wmc();              \
+               (v);                    \
+       })
+
+#endif /* _URCU_SYSTEM_H */