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x86 PAT: consolidate old memtype new memtype check into a function

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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>
This commit is contained in:
venkatesh.pallipadi@intel.com
2009-01-09 16:13:10 -08:00
committed by Ingo Molnar
parent a367061311
commit afc7d20c84
2 changed files with 20 additions and 11 deletions
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19
arch/x86/include/asm/pgtable.h
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@ -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