x86: PAT add set_memory_wc() interface

Add a set_memory_wc interface(), similar to set_memory_uc interface.
Callers has to call set_memory_uc, set_memory_wb and
set_memory_wc, set_memory_wb as pairs.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 21 insertions, 0 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 938df5e8402b..270cab2e6030 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -787,6 +787,25 @@ int set_memory_uc(unsigned long addr, int numpages)
 }
 EXPORT_SYMBOL(set_memory_uc);
 
+int _set_memory_wc(unsigned long addr, int numpages)
+{
+        return change_page_attr_set(addr, numpages,
+                                    __pgprot(_PAGE_CACHE_WC));
+}
+
+int set_memory_wc(unsigned long addr, int numpages)
+{
+        if (!pat_wc_enabled)
+                return set_memory_uc(addr, numpages);
+
+        if (reserve_memtype(addr, addr + numpages * PAGE_SIZE,
+                _PAGE_CACHE_WC, NULL))
+                return -EINVAL;
+
+        return _set_memory_wc(addr, numpages);
+}
+EXPORT_SYMBOL(set_memory_wc);
+
 int _set_memory_wb(unsigned long addr, int numpages)
 {
         return change_page_attr_clear(addr, numpages,
diff --git a/include/asm-x86/cacheflush.h b/include/asm-x86/cacheflush.h
index 5676fba10a09..90437d3f7610 100644
--- a/include/asm-x86/cacheflush.h
+++ b/include/asm-x86/cacheflush.h
@@ -35,8 +35,10 @@ int set_pages_ro(struct page *page, int numpages);
 int set_pages_rw(struct page *page, int numpages);
 
 int _set_memory_uc(unsigned long addr, int numpages);
+int _set_memory_wc(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_wb(unsigned long addr, int numpages);
 int set_memory_x(unsigned long addr, int numpages);
 int set_memory_nx(unsigned long addr, int numpages);