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. 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>