On Wed, May 01, 2013 at 12:42:38PM +0100, Will Deacon wrote: > Hi Steve, > > On Tue, Apr 30, 2013 at 05:30:46PM +0100, Steve Capper wrote: > > Add huge page support to ARM64, different huge page sizes are > > supported depending on the size of normal pages: > > > > PAGE_SIZE is 4K: > > 2MB - (pmds) these can be allocated at any time. > > 1024MB - (puds) usually allocated on bootup with the command line > > with something like: hugepagesz=1G hugepages=6 > > > > PAGE_SIZE is 64K: > > 512MB - (pmds), usually allocated on bootup via command line. > > [...] > > > diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h > > index 75fd13d..c3cac68 100644 > > --- a/arch/arm64/include/asm/pgtable-hwdef.h > > +++ b/arch/arm64/include/asm/pgtable-hwdef.h > > @@ -53,6 +53,7 @@ > > #define PTE_TYPE_MASK (_AT(pteval_t, 3) << 0) > > #define PTE_TYPE_FAULT (_AT(pteval_t, 0) << 0) > > #define PTE_TYPE_PAGE (_AT(pteval_t, 3) << 0) > > +#define PTE_TYPE_HUGEPAGE (_AT(pmdval_t, 1) << 0) > > This breaks PROT_NONE mappings, where you get: > > pte = pte_mkhuge(pte_modify(pte, newprot)); > > The pte_modify will clear the valid bit and set the prot_none bit (in order > to create a present, faulting entry) but then your pte_mkhuge will come in > and clobber that with a valid block entry. Thanks Will, I'll re-work the pte_mkhuge/pte_huge logic and get a PROT_NONE test case coded up. Cheers, -- Steve > > Will -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>