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authorvenkatesh.pallipadi@intel.com <venkatesh.pallipadi@intel.com>2009-01-09 16:13:10 -0800
committerIngo Molnar <mingo@elte.hu>2009-01-13 19:13:00 +0100
commitafc7d20c8429f32f19d47367fdc36eeed2334ec3 (patch)
treee817ea903498dcce184a758efb44d6e29223cfa3 /arch/x86/include/asm
parenta36706131182f5507d1e2cfbf391b0fa8d72203c (diff)
x86 PAT: consolidate old memtype new memtype check into a function
Impact: cleanup Move the new memtype old memtype allowed check to header so that is can be shared by other users. Subsequent patch uses this in pat.c in remap_pfn_range() code path. No functionality change in this patch. 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>
Diffstat (limited to 'arch/x86/include/asm')
-rw-r--r--arch/x86/include/asm/pgtable.h19
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 83e69f4a37f..06bbcbd66e9 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -341,6 +341,25 @@ static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
#define canon_pgprot(p) __pgprot(pgprot_val(p) & __supported_pte_mask)
+static inline int is_new_memtype_allowed(unsigned long flags,
+ unsigned long new_flags)
+{
+ /*
+ * Certain new memtypes are not allowed with certain
+ * requested memtype:
+ * - request is uncached, return cannot be write-back
+ * - request is write-combine, return cannot be write-back
+ */
+ if ((flags == _PAGE_CACHE_UC_MINUS &&
+ new_flags == _PAGE_CACHE_WB) ||
+ (flags == _PAGE_CACHE_WC &&
+ new_flags == _PAGE_CACHE_WB)) {
+ return 0;
+ }
+
+ return 1;
+}
+
#ifndef __ASSEMBLY__
/* Indicate that x86 has its own track and untrack pfn vma functions */
#define __HAVE_PFNMAP_TRACKING