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 <jeremy@xensource.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/mm/pgtable_32.c b/arch/x86/mm/pgtable_32.c
index f34e33d..c7db504 100644
--- a/arch/x86/mm/pgtable_32.c
+++ b/arch/x86/mm/pgtable_32.c
@@ -373,13 +373,6 @@
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 a195c3e..ed4c6f0 100644
--- a/include/asm-x86/pgtable-3level.h
+++ b/include/asm-x86/pgtable-3level.h
@@ -96,23 +96,14 @@
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) \