Messages in this thread | | | Date | Thu, 5 Jul 2012 20:37:46 +0800 | Subject | Re: [PATCH] mm: hugetlb: flush dcache before returning zeroed huge page to userspace | From | Hillf Danton <> |
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On Wed, Jul 4, 2012 at 10:32 PM, Will Deacon <will.deacon@arm.com> wrote: > When allocating and returning clear huge pages to userspace as a > response to a fault, we may zero and return a mapping to a previously > dirtied physical region (for example, it may have been written by > a private mapping which was freed as a result of an ftruncate on the > backing file). On architectures with Harvard caches, this can lead to > I/D inconsistency since the zeroed view may not be visible to the > instruction stream. > > This patch solves the problem by flushing the region after allocating > and clearing a new huge page. Note that PowerPC avoids this issue by > performing the flushing in their clear_user_page implementation to keep > the loader happy, however this is closely tied to the semantics of the > PG_arch_1 page flag which is architecture-specific. > > Acked-by: Catalin Marinas <catalin.marinas@arm.com> > Signed-off-by: Will Deacon <will.deacon@arm.com> > ---
Thanks:)
Acked-by: Hillf Danton <dhillf@gmail.com>
> mm/hugetlb.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index e198831..b83d026 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -2646,6 +2646,7 @@ retry: > goto out; > } > clear_huge_page(page, address, pages_per_huge_page(h)); > + flush_dcache_page(page); > __SetPageUptodate(page); > > if (vma->vm_flags & VM_MAYSHARE) { > -- > 1.7.4.1 >
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