samples/bpf: xdpsock: order memory on AArch64

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 <[email protected]> Acked-by: Björn Töpel <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]>
josf · Jul 27, 2018 · 598135e · 598135e
1 parent 08a8525
commit 598135e
Showing 1 changed file with 5 additions and 0 deletions.
diff --git 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)