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authorChristian Borntraeger <borntraeger@de.ibm.com>2014-12-07 22:01:59 +0100
committerChristian Borntraeger <borntraeger@de.ibm.com>2015-01-19 14:14:20 +0100
commit1760f1eb7ec485197bd3a8a9c13e4160bb740275 (patch)
tree8582fadb1d21e4e55fbd48f2f572018d05949566 /arch/x86/xen
parentda1a288d8562739aa8ba0273d4fb6b73b856c0d3 (diff)
downloadlinux-1760f1eb7ec485197bd3a8a9c13e4160bb740275.tar.bz2
x86/xen/p2m: Replace ACCESS_ONCE with READ_ONCE
ACCESS_ONCE does not work reliably on non-scalar types. For example gcc 4.6 and 4.7 might remove the volatile tag for such accesses during the SRA (scalar replacement of aggregates) step (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145) Change the p2m code to replace ACCESS_ONCE with READ_ONCE. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Juergen Gross <jgross@suse.com> Acked-by: David Vrabel <david.vrabel@citrix.com>
Diffstat (limited to 'arch/x86/xen')
-rw-r--r--arch/x86/xen/p2m.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index edbc7a63fd73..cb7101692a75 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -554,7 +554,7 @@ static bool alloc_p2m(unsigned long pfn)
mid_mfn = NULL;
}
- p2m_pfn = pte_pfn(ACCESS_ONCE(*ptep));
+ p2m_pfn = pte_pfn(READ_ONCE(*ptep));
if (p2m_pfn == PFN_DOWN(__pa(p2m_identity)) ||
p2m_pfn == PFN_DOWN(__pa(p2m_missing))) {
/* p2m leaf page is missing */