On Tue, Jul 24, 2012 at 02:09:04AM +0100, Cyril Chemparathy wrote: > This patch applies to PAGE_MASK, PMD_MASK, and PGDIR_MASK, where forcing > unsigned long math truncates the mask at the 32-bits. This clearly does bad > things on PAE systems. > > This patch fixes this problem by defining these masks as signed quantities. > We then rely on sign extension to do the right thing. > > Signed-off-by: Cyril Chemparathy <cy...@ti.com> > Signed-off-by: Vitaly Andrianov <vita...@ti.com> > --- > arch/arm/include/asm/page.h | 7 ++++++- > arch/arm/include/asm/pgtable-3level.h | 6 +++--- > 2 files changed, 9 insertions(+), 4 deletions(-) > > diff --git a/arch/arm/include/asm/page.h b/arch/arm/include/asm/page.h > index ecf9019..1c810d2 100644 > --- a/arch/arm/include/asm/page.h > +++ b/arch/arm/include/asm/page.h > @@ -13,7 +13,12 @@ > /* PAGE_SHIFT determines the page size */ > #define PAGE_SHIFT 12 > #define PAGE_SIZE (_AC(1,UL) << PAGE_SHIFT) > -#define PAGE_MASK (~(PAGE_SIZE-1)) > + > +/* > + * We do not use PAGE_SIZE in the following because we rely on sign > + * extension to appropriately extend upper bits for PAE systems > + */ > +#define PAGE_MASK (~((1 << PAGE_SHIFT) - 1))
Would it work if we use a 1ULL here and avoid the sign trick? I'm worried about some context where this would lose the sign. We could have an #ifdef here while the PGDIR/PMD masks are in a separate file already. -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
