Commit a30e32bd authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

asm-generic/tlb: Provide generic tlb_flush() based on flush_tlb_mm() 



When an architecture does not have (an efficient) flush_tlb_range(),
but instead always uses full TLB invalidates, the current generic
tlb_flush() is sub-optimal, for it will generate extra flushes in
order to keep the range small.

But if we cannot do range flushes, that is a moot concern. Optionally
provide this simplified default.

No change in behavior intended.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 5f307be1

include/asm-generic/tlb.h

+40 −1
Original line number Diff line number Diff line
@@ -114,7 +114,8 @@ 
 *    returns the smallest TLB entry size unmapped in this range.

 *

 * If an architecture does not provide tlb_flush() a default implementation

 * based on flush_tlb_range() will be used.

 * based on flush_tlb_range() will be used, unless MMU_GATHER_NO_RANGE is

 * specified, in which case we'll default to flush_tlb_mm().

 *

 * Additionally there are a few opt-in features:

 *
@@ -140,6 +141,9 @@ 
 *  the page-table pages. Required if you use HAVE_RCU_TABLE_FREE and your

 *  architecture uses the Linux page-tables natively.

 *

 *  MMU_GATHER_NO_RANGE

 *

 *  Use this if your architecture lacks an efficient flush_tlb_range().

 */

#define HAVE_GENERIC_MMU_GATHER
@@ -302,12 +306,45 @@ static inline void __tlb_reset_range(struct mmu_gather *tlb) 
	 */

}



#ifdef CONFIG_MMU_GATHER_NO_RANGE



#if defined(tlb_flush) || defined(tlb_start_vma) || defined(tlb_end_vma)

#error MMU_GATHER_NO_RANGE relies on default tlb_flush(), tlb_start_vma() and tlb_end_vma()

#endif



/*

 * When an architecture does not have efficient means of range flushing TLBs

 * there is no point in doing intermediate flushes on tlb_end_vma() to keep the

 * range small. We equally don't have to worry about page granularity or other

 * things.

 *

 * All we need to do is issue a full flush for any !0 range.

 */

static inline void tlb_flush(struct mmu_gather *tlb)

{

	if (tlb->end)

		flush_tlb_mm(tlb->mm);

}



static inline void

tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { }



#define tlb_end_vma tlb_end_vma

static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma) { }



#else /* CONFIG_MMU_GATHER_NO_RANGE */



#ifndef tlb_flush



#if defined(tlb_start_vma) || defined(tlb_end_vma)

#error Default tlb_flush() relies on default tlb_start_vma() and tlb_end_vma()

#endif



/*

 * When an architecture does not provide its own tlb_flush() implementation

 * but does have a reasonably efficient flush_vma_range() implementation

 * use that.

 */

static inline void tlb_flush(struct mmu_gather *tlb)

{

	if (tlb->fullmm || tlb->need_flush_all) {
@@ -348,6 +385,8 @@ tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { } 


#endif



#endif /* CONFIG_MMU_GATHER_NO_RANGE */



static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)

{

	if (!tlb->end)

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