ARC: Brown paper bag bug in macro for checking cache color

[karo-tx-linux.git] / arch / arc / mm / tlb.c

diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c
index 003d69ac6ffa63935a7bedf1089b61e238ff7a12..fe1c5a073afe4cf996d28b6486c6b296fbd94344 100644 (file)
--- a/arch/arc/mm/tlb.c
+++ b/arch/arc/mm/tlb.c
@@ -421,25 +421,41 @@ void create_tlb(struct vm_area_struct *vma, unsigned long address, pte_t *ptep)
 /*
  * Called at the end of pagefault, for a userspace mapped page
  *  -pre-install the corresponding TLB entry into MMU
- *  -Finalize the delayed D-cache flush (wback+inv kernel mapping)
+ *  -Finalize the delayed D-cache flush of kernel mapping of page due to
+ *     flush_dcache_page(), copy_user_page()
+ *
+ * Note that flush (when done) involves both WBACK - so physical page is
+ * in sync as well as INV - so any non-congruent aliases don't remain
  */
 void update_mmu_cache(struct vm_area_struct *vma, unsigned long vaddr_unaligned,
                      pte_t *ptep)
 {
        unsigned long vaddr = vaddr_unaligned & PAGE_MASK;
+       unsigned long paddr = pte_val(*ptep) & PAGE_MASK;
 
        create_tlb(vma, vaddr, ptep);
 
-       /* icache doesn't snoop dcache, thus needs to be made coherent here */
-       if (vma->vm_flags & VM_EXEC) {
+       /*
+        * Exec page : Independent of aliasing/page-color considerations,
+        *             since icache doesn't snoop dcache on ARC, any dirty
+        *             K-mapping of a code page needs to be wback+inv so that
+        *             icache fetch by userspace sees code correctly.
+        * !EXEC page: If K-mapping is NOT congruent to U-mapping, flush it
+        *             so userspace sees the right data.
+        *  (Avoids the flush for Non-exec + congruent mapping case)
+        */
+       if ((vma->vm_flags & VM_EXEC) ||
+            addr_not_cache_congruent(paddr, vaddr)) {
                struct page *page = pfn_to_page(pte_pfn(*ptep));
 
-               /* if page was dcache dirty, flush now */
                int dirty = test_and_clear_bit(PG_arch_1, &page->flags);
                if (dirty) {
-                       unsigned long paddr =  pte_val(*ptep) & PAGE_MASK;
-                       __flush_dcache_page(paddr);
-                       __inv_icache_page(paddr, vaddr);
+                       /* wback + inv dcache lines */
+                       __flush_dcache_page(paddr, paddr);
+
+                       /* invalidate any existing icache lines */
+                       if (vma->vm_flags & VM_EXEC)
+                               __inv_icache_page(paddr, vaddr);
                }
        }
 }