xen/time: use READ_ONCE
Use READ_ONCE through the code, rather than explicit barriers.
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
diff --git a/drivers/xen/time.c b/drivers/xen/time.c
index 433fe24..71078425 100644
--- a/drivers/xen/time.c
+++ b/drivers/xen/time.c
@@ -25,7 +25,7 @@
if (BITS_PER_LONG < 64) {
u32 *p32 = (u32 *)p;
- u32 h, l;
+ u32 h, l, h2;
/*
* Read high then low, and then make sure high is
@@ -34,15 +34,14 @@
* XXX some clean way to make this endian-proof?
*/
do {
- h = p32[1];
- barrier();
- l = p32[0];
- barrier();
- } while (p32[1] != h);
+ h = READ_ONCE(p32[1]);
+ l = READ_ONCE(p32[0]);
+ h2 = READ_ONCE(p32[1]);
+ } while(h2 != h);
ret = (((u64)h) << 32) | l;
} else
- ret = *p;
+ ret = READ_ONCE(*p);
return ret;
}
@@ -66,9 +65,7 @@
*/
do {
state_time = get64(&state->state_entry_time);
- barrier();
- *res = *state;
- barrier();
+ *res = READ_ONCE(*state);
} while (get64(&state->state_entry_time) != state_time);
}