Commit 2520bd31 authored by venkatesh.pallipadi@intel.com's avatar venkatesh.pallipadi@intel.com Committed by H. Peter Anvin
Browse files

x86: PAT: add pgprot_writecombine() interface for drivers - v3 



Impact: New mm functionality.

Add pgprot_writecombine. pgprot_writecombine will be aliased to
pgprot_noncached when not supported by the architecture.

Signed-off-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 8a7b12f7

arch/x86/include/asm/pgtable.h

+3 −0
Original line number Diff line number Diff line
@@ -168,6 +168,9 @@ 


#ifndef __ASSEMBLY__



#define pgprot_writecombine	pgprot_writecombine

extern pgprot_t pgprot_writecombine(pgprot_t prot);



/*

 * ZERO_PAGE is a global shared page that is always zero: used

 * for zero-mapped memory areas etc..

arch/x86/mm/pat.c

+8 −0
Original line number Diff line number Diff line
@@ -832,6 +832,14 @@ void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn, 
	}

}



pgprot_t pgprot_writecombine(pgprot_t prot)

{

	if (pat_enabled)

		return __pgprot(pgprot_val(prot) | _PAGE_CACHE_WC);

	else

		return pgprot_noncached(prot);

}



#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)



/* get Nth element of the linked list */

include/asm-generic/pgtable.h

+4 −0
Original line number Diff line number Diff line
@@ -129,6 +129,10 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres 
#define move_pte(pte, prot, old_addr, new_addr)	(pte)

#endif



#ifndef pgprot_writecombine

#define pgprot_writecombine pgprot_noncached

#endif



/*

 * When walking page tables, get the address of the next boundary,

 * or the end address of the range if that comes earlier.  Although no