x86: PAT: change pgprot_noncached to uc_minus instead of strong uc - v3
Impact: mm behavior change.
Make pgprot_noncached uc_minus instead of strong UC. This will make
pgprot_noncached to be in line with ioremap_nocache() and all the other
APIs that map page uc_minus on uc request.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 7dcd94c..6968d4f 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -158,6 +158,14 @@
#define PGD_IDENT_ATTR 0x001 /* PRESENT (no other attributes) */
#endif
+/*
+ * Macro to mark a page protection value as UC-
+ */
+#define pgprot_noncached(prot) \
+ ((boot_cpu_data.x86 > 3) \
+ ? (__pgprot(pgprot_val(prot) | _PAGE_CACHE_UC_MINUS)) \
+ : (prot))
+
#ifndef __ASSEMBLY__
/*