1 files changed, 18 insertions, 5 deletions

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 804de18abcc2..71bb3159031a 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -149,7 +149,8 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
          * Don't allow anybody to remap normal RAM that we're using..
          */
         for (pfn = phys_addr >> PAGE_SHIFT;
-                                (pfn << PAGE_SHIFT) < last_addr; pfn++) {
+                                (pfn << PAGE_SHIFT) < (last_addr & PAGE_MASK);
+                                pfn++) {
 
                 int is_ram = page_is_ram(pfn);
 
@@ -176,11 +177,11 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
                 /*
                  * Do not fallback to certain memory types with certain
                  * requested type:
-                 * - request is uncached, return cannot be write-back
-                 * - request is uncached, return cannot be write-combine
+                 * - request is uc-, return cannot be write-back
+                 * - request is uc-, return cannot be write-combine
                  * - request is write-combine, return cannot be write-back
                  */
-                if ((prot_val == _PAGE_CACHE_UC &&
+                if ((prot_val == _PAGE_CACHE_UC_MINUS &&
                      (new_prot_val == _PAGE_CACHE_WB ||
                       new_prot_val == _PAGE_CACHE_WC)) ||
                     (prot_val == _PAGE_CACHE_WC &&
@@ -201,6 +202,9 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
         default:
                 prot = PAGE_KERNEL_NOCACHE;
                 break;
+        case _PAGE_CACHE_UC_MINUS:
+                prot = PAGE_KERNEL_UC_MINUS;
+                break;
         case _PAGE_CACHE_WC:
                 prot = PAGE_KERNEL_WC;
                 break;
@@ -255,7 +259,16 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
  */
 void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size)
 {
-        return __ioremap_caller(phys_addr, size, _PAGE_CACHE_UC,
+        /*
+         * Ideally, this should be:
+         *      pat_wc_enabled ? _PAGE_CACHE_UC : _PAGE_CACHE_UC_MINUS;
+         *
+         * Till we fix all X drivers to use ioremap_wc(), we will use
+         * UC MINUS.
+         */
+        unsigned long val = _PAGE_CACHE_UC_MINUS;
+
+        return __ioremap_caller(phys_addr, size, val,
                                 __builtin_return_address(0));
 }
 EXPORT_SYMBOL(ioremap_nocache);