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xen/time: use READ_ONCE

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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>
This commit is contained in:
Stefano Stabellini 2015-11-20 15:02:44 +00:00 committed by David Vrabel
parent 187b26a972
commit 2dd887e321
1 changed files with 7 additions and 10 deletions
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17
drivers/xen/time.c
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@ -25,7 +25,7 @@ static u64 get64(const u64 *p)
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 @@ static u64 get64(const u64 *p)
* 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 @@ void xen_get_runstate_snapshot(struct vcpu_runstate_info *res)
*/
do {
state_time = get64(&state->state_entry_time);
barrier();
*res = *state;
barrier();
*res = READ_ONCE(*state);
} while (get64(&state->state_entry_time) != state_time);
}