openkylin
/
platform_kernel-5.15
mirror of https://gitee.com/openkylin/platform_kernel-5.15.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

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>
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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
drivers/xen/time.c
View File

@ -25,7 +25,7 @@ static u64 get64(const u64 *p)
if (BITS_PER_LONG < 64) { if (BITS_PER_LONG < 64) {
u32 *p32 = (u32 *)p; u32 *p32 = (u32 *)p;
u32 h, l; u32 h, l, h2;
/* /*
* Read high then low, and then make sure high is * 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? * XXX some clean way to make this endian-proof?
*/ */
do { do {
h = p32[1]; h = READ_ONCE(p32[1]);
barrier(); l = READ_ONCE(p32[0]);
l = p32[0]; h2 = READ_ONCE(p32[1]);
barrier(); } while(h2 != h);
} while (p32[1] != h);
ret = (((u64)h) << 32) | l; ret = (((u64)h) << 32) | l;
} else } else
ret = *p; ret = READ_ONCE(*p);
return ret; return ret;
} }
@ -66,9 +65,7 @@ void xen_get_runstate_snapshot(struct vcpu_runstate_info *res)
*/ */
do { do {
state_time = get64(&state->state_entry_time); state_time = get64(&state->state_entry_time);
barrier(); *res = READ_ONCE(*state);
*res = *state;
barrier();
} while (get64(&state->state_entry_time) != state_time); } while (get64(&state->state_entry_time) != state_time);
} }