[PATCH] lock PTE before updating it in 440/BookE page fault handler

[pandora-kernel.git] / arch / ppc / mm / fault.c

diff --git a/arch/ppc/mm/fault.c b/arch/ppc/mm/fault.c
index 0217188..8e08ca3 100644 (file)
--- a/arch/ppc/mm/fault.c
+++ b/arch/ppc/mm/fault.c
@@ -202,6 +202,7 @@ good_area:
        /* an exec  - 4xx/Book-E allows for per-page execute permission */
        } else if (TRAP(regs) == 0x400) {
                pte_t *ptep;
+               pmd_t *pmdp;
 
 #if 0
                /* It would be nice to actually enforce the VM execute
@@ -215,21 +216,24 @@ good_area:
                /* Since 4xx/Book-E supports per-page execute permission,
                 * we lazily flush dcache to icache. */
                ptep = NULL;
-               if (get_pteptr(mm, address, &ptep) && pte_present(*ptep)) {
-                       struct page *page = pte_page(*ptep);
-
-                       if (! test_bit(PG_arch_1, &page->flags)) {
-                               flush_dcache_icache_page(page);
-                               set_bit(PG_arch_1, &page->flags);
+               if (get_pteptr(mm, address, &ptep, &pmdp)) {
+                       spinlock_t *ptl = pte_lockptr(mm, pmdp);
+                       spin_lock(ptl);
+                       if (pte_present(*ptep)) {
+                               struct page *page = pte_page(*ptep);
+
+                               if (!test_bit(PG_arch_1, &page->flags)) {
+                                       flush_dcache_icache_page(page);
+                                       set_bit(PG_arch_1, &page->flags);
+                               }
+                               pte_update(ptep, 0, _PAGE_HWEXEC);
+                               _tlbie(address);
+                               pte_unmap_unlock(ptep, ptl);
+                               up_read(&mm->mmap_sem);
+                               return 0;
                        }
-                       pte_update(ptep, 0, _PAGE_HWEXEC);
-                       _tlbie(address);
-                       pte_unmap(ptep);
-                       up_read(&mm->mmap_sem);
-                       return 0;
+                       pte_unmap_unlock(ptep, ptl);
                }
-               if (ptep != NULL)
-                       pte_unmap(ptep);
 #endif
        /* a read */
        } else {