From 0e5f35d0e4a8179cdfac115023f418126419e659 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Sun, 28 Apr 2013 09:37:28 +0000 Subject: [PATCH] powerpc: Don't truncate pgd_index wrongly With PGD_INDEX_SIZE set to 12 the existing macro doesn't work. Fix it to use PTRS_PER_PGD The idea originally was to have one more bit in the result of pgd_index() than PGD_INDEX_SIZE, so that if one had an address corresponding to the last PGD entry, and then incremented that address by PGD_SIZE, and took pgd_index() of that, you wouldn't end up with zero. The commit that introduced that dates back to 2002, and the code that was sensitive to that edge case has long since been refactored (several times), so there is no need for it these days. Signed-off-by: Aneesh Kumar K.V Acked-by: Paul Mackerras Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/pgtable-ppc64.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h index 0182c20..e3d55f6f 100644 --- a/arch/powerpc/include/asm/pgtable-ppc64.h +++ b/arch/powerpc/include/asm/pgtable-ppc64.h @@ -167,8 +167,7 @@ * Find an entry in a page-table-directory. We combine the address region * (the high order N bits) and the pgd portion of the address. */ -/* to avoid overflow in free_pgtables we don't use PTRS_PER_PGD here */ -#define pgd_index(address) (((address) >> (PGDIR_SHIFT)) & 0x1ff) +#define pgd_index(address) (((address) >> (PGDIR_SHIFT)) & (PTRS_PER_PGD - 1)) #define pgd_offset(mm, address) ((mm)->pgd + pgd_index(address)) -- 2.7.4