From aeed5fce37196e09b4dac3a1c00d8b7122e040ce Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Tue, 6 May 2008 20:49:23 +0100 Subject: x86: fix PAE pmd_bad bootup warning Fix warning from pmd_bad() at bootup on a HIGHMEM64G HIGHPTE x86_32. That came from 9fc34113f6880b215cbea4e7017fc818700384c2 x86: debug pmd_bad(); but we understand now that the typecasting was wrong for PAE in the previous version: pagetable pages above 4GB looked bad and stopped Arjan from booting. And revert that cded932b75ab0a5f9181ee3da34a0a488d1a14fd x86: fix pmd_bad and pud_bad to support huge pages. It was the wrong way round: we shouldn't weaken every pmd_bad and pud_bad check to let huge pages slip through - in part they check that we _don't_ have a huge page where it's not expected. Put the x86 pmd_bad() and pud_bad() definitions back to what they have long been: they can be improved (x86_32 should use PTE_MASK, to stop PAE thinking junk in the upper word is good; and x86_64 should follow x86_32's stricter comparison, to stop thinking any subset of required bits is good); but that should be a later patch. Fix Hans' good observation that follow_page() will never find pmd_huge() because that would have already failed the pmd_bad test: test pmd_huge in between the pmd_none and pmd_bad tests. Tighten x86's pmd_huge() check? No, once it's a hugepage entry, it can get quite far from a good pmd: for example, PROT_NONE leaves it with only ACCESSED of the KERN_PGTABLE bits. However... though follow_page() contains this and another test for huge pages, so it's nice to keep it working on them, where does it actually get called on a huge page? get_user_pages() checks is_vm_hugetlb_page(vma) to to call alternative hugetlb processing, as does unmap_vmas() and others. Signed-off-by: Hugh Dickins Earlier-version-tested-by: Ingo Molnar Cc: Thomas Gleixner Cc: Jeff Chua Cc: Hans Rosenfeld Cc: Arjan van de Ven Signed-off-by: Linus Torvalds --- include/asm-x86/pgtable_64.h | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'include/asm-x86/pgtable_64.h') diff --git a/include/asm-x86/pgtable_64.h b/include/asm-x86/pgtable_64.h index a3bbf87..efe83dc 100644 --- a/include/asm-x86/pgtable_64.h +++ b/include/asm-x86/pgtable_64.h @@ -158,14 +158,12 @@ static inline unsigned long pgd_bad(pgd_t pgd) static inline unsigned long pud_bad(pud_t pud) { - return pud_val(pud) & - ~(PTE_MASK | _KERNPG_TABLE | _PAGE_USER | _PAGE_PSE | _PAGE_NX); + return pud_val(pud) & ~(PTE_MASK | _KERNPG_TABLE | _PAGE_USER); } static inline unsigned long pmd_bad(pmd_t pmd) { - return pmd_val(pmd) & - ~(PTE_MASK | _KERNPG_TABLE | _PAGE_USER | _PAGE_PSE | _PAGE_NX); + return pmd_val(pmd) & ~(PTE_MASK | _KERNPG_TABLE | _PAGE_USER); } #define pte_none(x) (!pte_val((x))) -- cgit v1.1