From: Jeremy Fitzhardinge Date: Mon, 4 Feb 2008 15:48:02 +0000 (+0100) Subject: x86: revert "defer cr3 reload when doing pud_clear()" X-Git-Tag: v2.6.25-rc1~1057^2~45 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a67ad9c9f82342a9b320fdad204a490727ef4a18;p=linux-2.6 x86: revert "defer cr3 reload when doing pud_clear()" Revert "defer cr3 reload when doing pud_clear()" since I'm going to replace it. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- diff --git a/arch/x86/mm/pgtable_32.c b/arch/x86/mm/pgtable_32.c index f34e33d184..c7db504be1 100644 --- a/arch/x86/mm/pgtable_32.c +++ b/arch/x86/mm/pgtable_32.c @@ -373,13 +373,6 @@ void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte) void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd) { - /* This is called just after the pmd has been detached from - the pgd, which requires a full tlb flush to be recognized - by the CPU. Rather than incurring multiple tlb flushes - while the address space is being pulled down, make the tlb - gathering machinery do a full flush when we're done. */ - tlb->fullmm = 1; - paravirt_release_pd(__pa(pmd) >> PAGE_SHIFT); tlb_remove_page(tlb, virt_to_page(pmd)); } diff --git a/include/asm-x86/pgtable-3level.h b/include/asm-x86/pgtable-3level.h index a195c3e757..ed4c6f0e57 100644 --- a/include/asm-x86/pgtable-3level.h +++ b/include/asm-x86/pgtable-3level.h @@ -96,23 +96,14 @@ static inline void pud_clear(pud_t *pudp) set_pud(pudp, __pud(0)); /* - * In principle we need to do a cr3 reload here to make sure - * the processor recognizes the changed pgd. In practice, all - * the places where pud_clear() gets called are followed by - * full tlb flushes anyway, so we can defer the cost here. + * Pentium-II erratum A13: in PAE mode we explicitly have to flush + * the TLB via cr3 if the top-level pgd is changed... * - * Specifically: - * - * mm/memory.c:free_pmd_range() - immediately after the - * pud_clear() it does a pmd_free_tlb(). We change the - * mmu_gather structure to do a full tlb flush (which has the - * effect of reloading cr3) when the pagetable free is - * complete. - * - * arch/x86/mm/hugetlbpage.c:huge_pmd_unshare() - the call to - * this is followed by a flush_tlb_range, which on x86 does a - * full tlb flush. + * XXX I don't think we need to worry about this here, since + * when clearing the pud, the calling code needs to flush the + * tlb anyway. But do it now for safety's sake. - jsgf */ + write_cr3(read_cr3()); } #define pud_page(pud) \