alpha: allocate membarrier system call number

The membarrier syscall has been allocated in Linux 4.13, allocate its
number in our architecture header if the system headers don't allocate
it.

Change-Id: Iebb77b94bf803a7a8b7ebd9f4124219f386334ae
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/include/urcu/arch/alpha.h b/include/urcu/arch/alpha.h
index e61f82c0728047528acf484d74cf7011a892914c..dc33e28d3c1966863bff4775a4bc308f4e179cb4 100644 (file)
--- a/include/urcu/arch/alpha.h
+++ b/include/urcu/arch/alpha.h
@@ -33,6 +33,14 @@ extern "C" {
 #define cmm_wmb()                      __asm__ __volatile__ ("wmb":::"memory")
 #define cmm_read_barrier_depends()     __asm__ __volatile__ ("mb":::"memory")
 
+/*
+ * On Linux, define the membarrier system call number if not yet available in
+ * the system headers.
+ */
+#if (defined(__linux__) && !defined(__NR_membarrier))
+#define __NR_membarrier                517
+#endif
+
 #ifdef __cplusplus
 }
 #endif