diff options
Diffstat (limited to 'include/asm-x86/pgtable-3level.h')
| -rw-r--r-- | include/asm-x86/pgtable-3level.h | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/include/asm-x86/pgtable-3level.h b/include/asm-x86/pgtable-3level.h index ed4c6f0e57e..a195c3e757b 100644 --- a/include/asm-x86/pgtable-3level.h +++ b/include/asm-x86/pgtable-3level.h @@ -96,14 +96,23 @@ static inline void pud_clear(pud_t *pudp) set_pud(pudp, __pud(0)); /* - * Pentium-II erratum A13: in PAE mode we explicitly have to flush - * the TLB via cr3 if the top-level pgd is changed... + * 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. * - * 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 + * 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. */ - write_cr3(read_cr3()); } #define pud_page(pud) \ |