1 files changed, 46 insertions, 39 deletions

diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c
index 56ee153..c9b97e9 100644
--- a/arch/arm/mm/fault-armv.c
+++ b/arch/arm/mm/fault-armv.c
@@ -36,28 +36,12 @@ static unsigned long shared_pte_mask = L_PTE_MT_BUFFERABLE;
  * Therefore those configurations which might call adjust_pte (those
  * without CONFIG_CPU_CACHE_VIPT) cannot support split page_table_lock.
  */
-static int adjust_pte(struct vm_area_struct *vma, unsigned long address)
+static int do_adjust_pte(struct vm_area_struct *vma, unsigned long address,
+	unsigned long pfn, pte_t *ptep)
 {
-	pgd_t *pgd;
-	pmd_t *pmd;
-	pte_t *pte, entry;
+	pte_t entry = *ptep;
 	int ret;
 
-	pgd = pgd_offset(vma->vm_mm, address);
-	if (pgd_none(*pgd))
-		goto no_pgd;
-	if (pgd_bad(*pgd))
-		goto bad_pgd;
-
-	pmd = pmd_offset(pgd, address);
-	if (pmd_none(*pmd))
-		goto no_pmd;
-	if (pmd_bad(*pmd))
-		goto bad_pmd;
-
-	pte = pte_offset_map(pmd, address);
-	entry = *pte;
-
 	/*
 	 * If this page is present, it's actually being shared.
 	 */
@@ -68,33 +52,55 @@ static int adjust_pte(struct vm_area_struct *vma, unsigned long address)
 	 * fault (ie, is old), we can safely ignore any issues.
 	 */
 	if (ret && (pte_val(entry) & L_PTE_MT_MASK) != shared_pte_mask) {
-		unsigned long pfn = pte_pfn(entry);
 		flush_cache_page(vma, address, pfn);
 		outer_flush_range((pfn << PAGE_SHIFT),
 				  (pfn << PAGE_SHIFT) + PAGE_SIZE);
 		pte_val(entry) &= ~L_PTE_MT_MASK;
 		pte_val(entry) |= shared_pte_mask;
-		set_pte_at(vma->vm_mm, address, pte, entry);
+		set_pte_at(vma->vm_mm, address, ptep, entry);
 		flush_tlb_page(vma, address);
 	}
-	pte_unmap(pte);
+
 	return ret;
+}
+
+static int adjust_pte(struct vm_area_struct *vma, unsigned long address,
+	unsigned long pfn)
+{
+	spinlock_t *ptl;
+	pgd_t *pgd;
+	pmd_t *pmd;
+	pte_t *pte;
+	int ret;
+
+	pgd = pgd_offset(vma->vm_mm, address);
+	if (pgd_none_or_clear_bad(pgd))
+		return 0;
+
+	pmd = pmd_offset(pgd, address);
+	if (pmd_none_or_clear_bad(pmd))
+		return 0;
 
-bad_pgd:
-	pgd_ERROR(*pgd);
-	pgd_clear(pgd);
-no_pgd:
-	return 0;
-
-bad_pmd:
-	pmd_ERROR(*pmd);
-	pmd_clear(pmd);
-no_pmd:
-	return 0;
+	/*
+	 * This is called while another page table is mapped, so we
+	 * must use the nested version.  This also means we need to
+	 * open-code the spin-locking.
+	 */
+	ptl = pte_lockptr(vma->vm_mm, pmd);
+	pte = pte_offset_map_nested(pmd, address);
+	spin_lock(ptl);
+
+	ret = do_adjust_pte(vma, address, pfn, pte);
+
+	spin_unlock(ptl);
+	pte_unmap_nested(pte);
+
+	return ret;
 }
 
 static void
-make_coherent(struct address_space *mapping, struct vm_area_struct *vma, unsigned long addr, unsigned long pfn)
+make_coherent(struct address_space *mapping, struct vm_area_struct *vma,
+	unsigned long addr, pte_t *ptep, unsigned long pfn)
 {
 	struct mm_struct *mm = vma->vm_mm;
 	struct vm_area_struct *mpnt;
@@ -122,11 +128,11 @@ make_coherent(struct address_space *mapping, struct vm_area_struct *vma, unsigne
 		if (!(mpnt->vm_flags & VM_MAYSHARE))
 			continue;
 		offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
-		aliases += adjust_pte(mpnt, mpnt->vm_start + offset);
+		aliases += adjust_pte(mpnt, mpnt->vm_start + offset, pfn);
 	}
 	flush_dcache_mmap_unlock(mapping);
 	if (aliases)
-		adjust_pte(vma, addr);
+		do_adjust_pte(vma, addr, pfn, ptep);
 	else
 		flush_cache_page(vma, addr, pfn);
 }
@@ -144,9 +150,10 @@ make_coherent(struct address_space *mapping, struct vm_area_struct *vma, unsigne
  *
  * Note that the pte lock will be held.
  */
-void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
+void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr,
+	pte_t *ptep)
 {
-	unsigned long pfn = pte_pfn(pte);
+	unsigned long pfn = pte_pfn(*ptep);
 	struct address_space *mapping;
 	struct page *page;
 
@@ -168,7 +175,7 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
 #endif
 	if (mapping) {
 		if (cache_is_vivt())
-			make_coherent(mapping, vma, addr, pfn);
+			make_coherent(mapping, vma, addr, ptep, pfn);
 		else if (vma->vm_flags & VM_EXEC)
 			__flush_icache_all();
 	}