4 files changed, 63 insertions, 17 deletions

diff --git a/Documentation/x86/pat.txt b/Documentation/x86/pat.txt
index db0de6cfc351..54944c71b819 100644
--- a/Documentation/x86/pat.txt
+++ b/Documentation/x86/pat.txt
@@ -48,6 +48,9 @@ set_memory_uc          |    UC-   |    --      |       --         |
 set_memory_wc          |    WC    |    --      |       --         |
  set_memory_wb         |          |            |                  |
                        |          |            |                  |
+set_memory_wt          |    WT    |    --      |       --         |
+ set_memory_wb         |          |            |                  |
+                       |          |            |                  |
 pci sysfs resource     |    --    |    --      |       UC-        |
                        |          |            |                  |
 pci sysfs resource_wc  |    --    |    --      |       WC         |
@@ -150,8 +153,8 @@ can be more restrictive, in case of any existing aliasing for that address.
 For example: If there is an existing uncached mapping, a new ioremap_wc can
 return uncached mapping in place of write-combine requested.
 
-set_memory_[uc|wc] and set_memory_wb should be used in pairs, where driver will
-first make a region uc or wc and switch it back to wb after use.
+set_memory_[uc|wc|wt] and set_memory_wb should be used in pairs, where driver
+will first make a region uc, wc or wt and switch it back to wb after use.
 
 Over time writes to /proc/mtrr will be deprecated in favor of using PAT based
 interfaces. Users writing to /proc/mtrr are suggested to use above interfaces.
@@ -159,7 +162,7 @@ interfaces. Users writing to /proc/mtrr are suggested to use above interfaces.
 Drivers should use ioremap_[uc|wc] to access PCI BARs with [uc|wc] access
 types.
 
-Drivers should use set_memory_[uc|wc] to set access type for RAM ranges.
+Drivers should use set_memory_[uc|wc|wt] to set access type for RAM ranges.
 
 
 PAT debugging
diff --git a/arch/x86/include/asm/cacheflush.h b/arch/x86/include/asm/cacheflush.h
index 47c8e32f621a..b6f7457d12e4 100644
--- a/arch/x86/include/asm/cacheflush.h
+++ b/arch/x86/include/asm/cacheflush.h
@@ -8,7 +8,7 @@
 /*
  * The set_memory_* API can be used to change various attributes of a virtual
  * address range. The attributes include:
- * Cachability   : UnCached, WriteCombining, WriteBack
+ * Cachability   : UnCached, WriteCombining, WriteThrough, WriteBack
  * Executability : eXeutable, NoteXecutable
  * Read/Write    : ReadOnly, ReadWrite
  * Presence      : NotPresent
@@ -35,9 +35,11 @@
 
 int _set_memory_uc(unsigned long addr, int numpages);
 int _set_memory_wc(unsigned long addr, int numpages);
+int _set_memory_wt(unsigned long addr, int numpages);
 int _set_memory_wb(unsigned long addr, int numpages);
 int set_memory_uc(unsigned long addr, int numpages);
 int set_memory_wc(unsigned long addr, int numpages);
+int set_memory_wt(unsigned long addr, int numpages);
 int set_memory_wb(unsigned long addr, int numpages);
 int set_memory_x(unsigned long addr, int numpages);
 int set_memory_nx(unsigned long addr, int numpages);
@@ -48,10 +50,12 @@ int set_memory_4k(unsigned long addr, int numpages);
 
 int set_memory_array_uc(unsigned long *addr, int addrinarray);
 int set_memory_array_wc(unsigned long *addr, int addrinarray);
+int set_memory_array_wt(unsigned long *addr, int addrinarray);
 int set_memory_array_wb(unsigned long *addr, int addrinarray);
 
 int set_pages_array_uc(struct page **pages, int addrinarray);
 int set_pages_array_wc(struct page **pages, int addrinarray);
+int set_pages_array_wt(struct page **pages, int addrinarray);
 int set_pages_array_wb(struct page **pages, int addrinarray);
 
 /*
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 07cd46a8f30a..8405c0c6a535 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -42,6 +42,9 @@ int ioremap_change_attr(unsigned long vaddr, unsigned long size,
         case _PAGE_CACHE_MODE_WC:
                 err = _set_memory_wc(vaddr, nrpages);
                 break;
+        case _PAGE_CACHE_MODE_WT:
+                err = _set_memory_wt(vaddr, nrpages);
+                break;
         case _PAGE_CACHE_MODE_WB:
                 err = _set_memory_wb(vaddr, nrpages);
                 break;
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 31b4f3fd1207..727158cb3b3c 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -1503,12 +1503,10 @@ EXPORT_SYMBOL(set_memory_uc);
 static int _set_memory_array(unsigned long *addr, int addrinarray,
                 enum page_cache_mode new_type)
 {
+        enum page_cache_mode set_type;
         int i, j;
         int ret;
 
-        /*
-         * for now UC MINUS. see comments in ioremap_nocache()
-         */
         for (i = 0; i < addrinarray; i++) {
                 ret = reserve_memtype(__pa(addr[i]), __pa(addr[i]) + PAGE_SIZE,
                                         new_type, NULL);
@@ -1516,9 +1514,12 @@ static int _set_memory_array(unsigned long *addr, int addrinarray,
                         goto out_free;
         }
 
+        /* If WC, set to UC- first and then WC */
+        set_type = (new_type == _PAGE_CACHE_MODE_WC) ?
+                                _PAGE_CACHE_MODE_UC_MINUS : new_type;
+
         ret = change_page_attr_set(addr, addrinarray,
-                                   cachemode2pgprot(_PAGE_CACHE_MODE_UC_MINUS),
-                                   1);
+                                   cachemode2pgprot(set_type), 1);
 
         if (!ret && new_type == _PAGE_CACHE_MODE_WC)
                 ret = change_page_attr_set_clr(addr, addrinarray,
@@ -1550,6 +1551,12 @@ int set_memory_array_wc(unsigned long *addr, int addrinarray)
 }
 EXPORT_SYMBOL(set_memory_array_wc);
 
+int set_memory_array_wt(unsigned long *addr, int addrinarray)
+{
+        return _set_memory_array(addr, addrinarray, _PAGE_CACHE_MODE_WT);
+}
+EXPORT_SYMBOL_GPL(set_memory_array_wt);
+
 int _set_memory_wc(unsigned long addr, int numpages)
 {
         int ret;
@@ -1575,21 +1582,39 @@ int set_memory_wc(unsigned long addr, int numpages)
         ret = reserve_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE,
                 _PAGE_CACHE_MODE_WC, NULL);
         if (ret)
-                goto out_err;
+                return ret;
 
         ret = _set_memory_wc(addr, numpages);
         if (ret)
-                goto out_free;
+                free_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE);
 
-        return 0;
-
-out_free:
-        free_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE);
-out_err:
         return ret;
 }
 EXPORT_SYMBOL(set_memory_wc);
 
+int _set_memory_wt(unsigned long addr, int numpages)
+{
+        return change_page_attr_set(&addr, numpages,
+                                    cachemode2pgprot(_PAGE_CACHE_MODE_WT), 0);
+}
+
+int set_memory_wt(unsigned long addr, int numpages)
+{
+        int ret;
+
+        ret = reserve_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE,
+                              _PAGE_CACHE_MODE_WT, NULL);
+        if (ret)
+                return ret;
+
+        ret = _set_memory_wt(addr, numpages);
+        if (ret)
+                free_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(set_memory_wt);
+
 int _set_memory_wb(unsigned long addr, int numpages)
 {
         /* WB cache mode is hard wired to all cache attribute bits being 0 */
@@ -1680,6 +1705,7 @@ static int _set_pages_array(struct page **pages, int addrinarray,
 {
         unsigned long start;
         unsigned long end;
+        enum page_cache_mode set_type;
         int i;
         int free_idx;
         int ret;
@@ -1693,8 +1719,12 @@ static int _set_pages_array(struct page **pages, int addrinarray,
                         goto err_out;
         }
 
+        /* If WC, set to UC- first and then WC */
+        set_type = (new_type == _PAGE_CACHE_MODE_WC) ?
+                                _PAGE_CACHE_MODE_UC_MINUS : new_type;
+
         ret = cpa_set_pages_array(pages, addrinarray,
-                        cachemode2pgprot(_PAGE_CACHE_MODE_UC_MINUS));
+                                  cachemode2pgprot(set_type));
         if (!ret && new_type == _PAGE_CACHE_MODE_WC)
                 ret = change_page_attr_set_clr(NULL, addrinarray,
                                                cachemode2pgprot(
@@ -1728,6 +1758,12 @@ int set_pages_array_wc(struct page **pages, int addrinarray)
 }
 EXPORT_SYMBOL(set_pages_array_wc);
 
+int set_pages_array_wt(struct page **pages, int addrinarray)
+{
+        return _set_pages_array(pages, addrinarray, _PAGE_CACHE_MODE_WT);
+}
+EXPORT_SYMBOL_GPL(set_pages_array_wt);
+
 int set_pages_wb(struct page *page, int numpages)
 {
         unsigned long addr = (unsigned long)page_address(page);