From afc7d20c8429f32f19d47367fdc36eeed2334ec3 Mon Sep 17 00:00:00 2001 From: "venkatesh.pallipadi@intel.com" Date: Fri, 9 Jan 2009 16:13:10 -0800 Subject: 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 Signed-off-by: Suresh Siddha Signed-off-by: Ingo Molnar --- arch/x86/include/asm/pgtable.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'arch/x86/include/asm/pgtable.h') diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 83e69f4a37f0..06bbcbd66e9c 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 -- cgit v1.2.1