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Commit 2c3cf556 authored by Rik van Riel's avatar Rik van Riel Committed by Mel Gorman
Browse files

x86/mm: Introduce pte_accessible() 



We need pte_present to return true for _PAGE_PROTNONE pages, to indicate that
the pte is associated with a page.

However, for TLB flushing purposes, we would like to know whether the pte
points to an actually accessible page.  This allows us to skip remote TLB
flushes for pages that are not actually accessible.

Fill in this method for x86 and provide a safe (but slower) method
on other architectures.

Signed-off-by: default avatarRik van Riel <riel@redhat.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Fixed-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-66p11te4uj23gevgh4j987ip@git.kernel.org


[ Added Linus's review fixes. ]
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent cef23d9d

arch/x86/include/asm/pgtable.h

+6 −0
Original line number Diff line number Diff line
@@ -407,6 +407,12 @@ static inline int pte_present(pte_t a) 
	return pte_flags(a) & (_PAGE_PRESENT | _PAGE_PROTNONE);

}



#define pte_accessible pte_accessible

static inline int pte_accessible(pte_t a)

{

	return pte_flags(a) & _PAGE_PRESENT;

}



static inline int pte_hidden(pte_t pte)

{

	return pte_flags(pte) & _PAGE_HIDDEN;

include/asm-generic/pgtable.h

+4 −0
Original line number Diff line number Diff line
@@ -219,6 +219,10 @@ static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b) 
#define move_pte(pte, prot, old_addr, new_addr)	(pte)

#endif



#ifndef pte_accessible

# define pte_accessible(pte)		((void)(pte),1)

#endif



#ifndef flush_tlb_fix_spurious_fault

#define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)

#endif