[PATCH v2 bpf-next] samples/bpf: xdpsock: order memory on AArch64

[Brian Brooks]

Define u_smp_rmb() and u_smp_wmb() to respective barrier instructions.
This ensures the processor will order accesses to queue indices against
accesses to queue ring entries.

Signed-off-by: Brian Brooks <brian.bro...@linaro.org>
---
 samples/bpf/xdpsock_user.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/samples/bpf/xdpsock_user.c b/samples/bpf/xdpsock_user.c
index 5904b1543831..1e82f7c617c3 100644
--- a/samples/bpf/xdpsock_user.c
+++ b/samples/bpf/xdpsock_user.c
@@ -145,8 +145,13 @@ static void dump_stats(void);
        } while (0)
 
 #define barrier() __asm__ __volatile__("": : :"memory")
+#ifdef __aarch64__
+#define u_smp_rmb() __asm__ __volatile__("dmb ishld": : :"memory")
+#define u_smp_wmb() __asm__ __volatile__("dmb ishst": : :"memory")
+#else
 #define u_smp_rmb() barrier()
 #define u_smp_wmb() barrier()
+#endif
 #define likely(x) __builtin_expect(!!(x), 1)
 #define unlikely(x) __builtin_expect(!!(x), 0)
 
-- 
2.18.0