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-rw-r--r--arch/powerpc/mm/pgtable_64.c32
1 files changed, 32 insertions, 0 deletions
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 3124a20d0fab..cdf2123d46db 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -646,6 +646,28 @@ pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
return pgtable;
}
+void pmdp_huge_split_prepare(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp)
+{
+ VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+ VM_BUG_ON(REGION_ID(address) != USER_REGION_ID);
+
+ /*
+ * We can't mark the pmd none here, because that will cause a race
+ * against exit_mmap. We need to continue mark pmd TRANS HUGE, while
+ * we spilt, but at the same time we wan't rest of the ppc64 code
+ * not to insert hash pte on this, because we will be modifying
+ * the deposited pgtable in the caller of this function. Hence
+ * clear the _PAGE_USER so that we move the fault handling to
+ * higher level function and that will serialize against ptl.
+ * We need to flush existing hash pte entries here even though,
+ * the translation is still valid, because we will withdraw
+ * pgtable_t after this.
+ */
+ pmd_hugepage_update(vma->vm_mm, address, pmdp, _PAGE_USER, 0);
+}
+
+
/*
* set a new huge pmd. We should not be called for updating
* an existing pmd entry. That should go via pmd_hugepage_update.
@@ -663,10 +685,20 @@ void set_pmd_at(struct mm_struct *mm, unsigned long addr,
return set_pte_at(mm, addr, pmdp_ptep(pmdp), pmd_pte(pmd));
}
+/*
+ * We use this to invalidate a pmdp entry before switching from a
+ * hugepte to regular pmd entry.
+ */
void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
pmd_t *pmdp)
{
pmd_hugepage_update(vma->vm_mm, address, pmdp, _PAGE_PRESENT, 0);
+
+ /*
+ * This ensures that generic code that rely on IRQ disabling
+ * to prevent a parallel THP split work as expected.
+ */
+ kick_all_cpus_sync();
}
/*