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| author | Christian Borntraeger <borntraeger@de.ibm.com> | 2014-12-07 22:01:59 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-03-06 14:57:43 -0800 |
| commit | 24c94559aff487245e423acffd05bc751a43674f (patch) | |
| tree | 2af617a875b09de79a7980e28235c75b9db2f825 | |
| parent | dcc2e51a1fc91c2a631ed3ea5afed22c6aa13728 (diff) | |
| download | lwn-24c94559aff487245e423acffd05bc751a43674f.tar.gz lwn-24c94559aff487245e423acffd05bc751a43674f.zip | |
x86/xen/p2m: Replace ACCESS_ONCE with READ_ONCE
commit 1760f1eb7ec485197bd3a8a9c13e4160bb740275 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/xen/p2m.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 70fb5075c901..376a0a9dc670 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 */ |