[PATCH 6/6] Set up MTRR entries within set_memory_wc

[Thomas Schlichter]

If PAT is not enabled, set up write combining MTRR entries in set_memory_wc().

Signed-off-by: Thomas Schlichter <thomas.schlichter@xxxxxx>
---
 arch/x86/mm/pageattr.c |   10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index dd38bfb..c25f697 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -23,6 +23,7 @@
 #include <asm/pgalloc.h>
 #include <asm/proto.h>
 #include <asm/pat.h>
+#include <asm/mtrr.h>
 
 /*
  * The current flushing context - we pass it instead of 5 arguments:
@@ -1010,8 +1011,13 @@ int set_memory_wc(unsigned long addr, int numpages)
 {
 	int ret;
 
-	if (!pat_enabled)
-		return set_memory_uc(addr, numpages);
+	if (!pat_enabled) {
+		ret = set_memory_uc(addr, numpages);
+		if (!ret)
+			mtrr_add_unaligned(__pa(addr), numpages * PAGE_SIZE,
+					   MTRR_TYPE_WRCOMB, false);
+		return ret;
+	}
 
 	ret = reserve_memtype(__pa(addr), __pa(addr) + numpages * PAGE_SIZE,
 		_PAGE_CACHE_WC, NULL);
-- 
1.6.5


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