Linux-libre 4.5-gnu

1 files changed, 42 insertions, 65 deletions

diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index e92cb2146..cdf2123d4 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -359,7 +359,7 @@ struct page *pud_page(pud_t pud)
 struct page *pmd_page(pmd_t pmd)
 {
 	if (pmd_trans_huge(pmd) || pmd_huge(pmd))
-		return pfn_to_page(pmd_pfn(pmd));
+		return pte_page(pmd_pte(pmd));
 	return virt_to_page(pmd_page_vaddr(pmd));
 }
 
@@ -604,55 +604,6 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma,
 }
 
 /*
- * We mark the pmd splitting and invalidate all the hpte
- * entries for this hugepage.
- */
-void pmdp_splitting_flush(struct vm_area_struct *vma,
-			  unsigned long address, pmd_t *pmdp)
-{
-	unsigned long old, tmp;
-
-	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
-
-#ifdef CONFIG_DEBUG_VM
-	WARN_ON(!pmd_trans_huge(*pmdp));
-	assert_spin_locked(&vma->vm_mm->page_table_lock);
-#endif
-
-#ifdef PTE_ATOMIC_UPDATES
-
-	__asm__ __volatile__(
-	"1:	ldarx	%0,0,%3\n\
-		andi.	%1,%0,%6\n\
-		bne-	1b \n\
-		ori	%1,%0,%4 \n\
-		stdcx.	%1,0,%3 \n\
-		bne-	1b"
-	: "=&r" (old), "=&r" (tmp), "=m" (*pmdp)
-	: "r" (pmdp), "i" (_PAGE_SPLITTING), "m" (*pmdp), "i" (_PAGE_BUSY)
-	: "cc" );
-#else
-	old = pmd_val(*pmdp);
-	*pmdp = __pmd(old | _PAGE_SPLITTING);
-#endif
-	/*
-	 * If we didn't had the splitting flag set, go and flush the
-	 * HPTE entries.
-	 */
-	trace_hugepage_splitting(address, old);
-	if (!(old & _PAGE_SPLITTING)) {
-		/* We need to flush the hpte */
-		if (old & _PAGE_HASHPTE)
-			hpte_do_hugepage_flush(vma->vm_mm, address, pmdp, old);
-	}
-	/*
-	 * This ensures that generic code that rely on IRQ disabling
-	 * to prevent a parallel THP split work as expected.
-	 */
-	kick_all_cpus_sync();
-}
-
-/*
  * We want to put the pgtable in pmd and use pgtable for tracking
  * the base page size hptes
  */
@@ -695,6 +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.
@@ -712,10 +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();
 }
 
 /*
@@ -759,22 +742,15 @@ void hpte_do_hugepage_flush(struct mm_struct *mm, unsigned long addr,
 
 static pmd_t pmd_set_protbits(pmd_t pmd, pgprot_t pgprot)
 {
-	pmd_val(pmd) |= pgprot_val(pgprot);
-	return pmd;
+	return __pmd(pmd_val(pmd) | pgprot_val(pgprot));
 }
 
 pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot)
 {
-	pmd_t pmd;
-	/*
-	 * For a valid pte, we would have _PAGE_PRESENT always
-	 * set. We use this to check THP page at pmd level.
-	 * leaf pte for huge page, bottom two bits != 00
-	 */
-	pmd_val(pmd) = pfn << PTE_RPN_SHIFT;
-	pmd_val(pmd) |= _PAGE_THP_HUGE;
-	pmd = pmd_set_protbits(pmd, pgprot);
-	return pmd;
+	unsigned long pmdv;
+
+	pmdv = pfn << PTE_RPN_SHIFT;
+	return pmd_set_protbits(__pmd(pmdv), pgprot);
 }
 
 pmd_t mk_pmd(struct page *page, pgprot_t pgprot)
@@ -784,10 +760,11 @@ pmd_t mk_pmd(struct page *page, pgprot_t pgprot)
 
 pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
 {
+	unsigned long pmdv;
 
-	pmd_val(pmd) &= _HPAGE_CHG_MASK;
-	pmd = pmd_set_protbits(pmd, newprot);
-	return pmd;
+	pmdv = pmd_val(pmd);
+	pmdv &= _HPAGE_CHG_MASK;
+	return pmd_set_protbits(__pmd(pmdv), newprot);
 }
 
 /*