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x86: PAT infrastructure patch

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Sets up pat_init() infrastructure.

PAT MSR has following setting.
	PAT
	|PCD
	||PWT
	|||
	000 WB		_PAGE_CACHE_WB
	001 WC		_PAGE_CACHE_WC
	010 UC-		_PAGE_CACHE_UC_MINUS
	011 UC		_PAGE_CACHE_UC

We are effectively changing WT from boot time setting to WC.
UC_MINUS is used to provide backward compatibility to existing /dev/mem
users(X).

reserve_memtype and free_memtype are new interfaces for maintaining alias-free
mapping. It is currently implemented in a simple way with a linked list and
not optimized. reserve and free tracks the effective memory type, as a result
of PAT and MTRR setting rather than what is actually requested in PAT.

pat_init piggy backs on mtrr_init as the rules for setting both pat and mtrr
are same.

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
2008-03-18 17:00:14 -07:00
committed by Ingo Molnar
parent d27554d874
commit 2e5d9c857d
10 changed files with 568 additions and 3 deletions
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4
arch/x86/mm/pageattr.c
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@@ -773,14 +773,14 @@ static inline int change_page_attr_clear(unsigned long addr, int numpages,
int set_memory_uc(unsigned long addr, int numpages)
{
return change_page_attr_set(addr, numpages,
__pgprot(_PAGE_PCD));
__pgprot(_PAGE_CACHE_UC));
}
EXPORT_SYMBOL(set_memory_uc);
int set_memory_wb(unsigned long addr, int numpages)
{
return change_page_attr_clear(addr, numpages,
__pgprot(_PAGE_PCD | _PAGE_PWT));
__pgprot(_PAGE_CACHE_MASK));
}
EXPORT_SYMBOL(set_memory_wb);