Commit 5f307be1 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

asm-generic/tlb, arch: Provide generic tlb_flush() based on flush_tlb_range() 



Provide a generic tlb_flush() implementation that relies on
flush_tlb_range(). This is a little awkward because flush_tlb_range()
assumes a VMA for range invalidation, but we no longer have one.

Audit of all flush_tlb_range() implementations shows only vma->vm_mm
and vma->vm_flags are used, and of the latter only VM_EXEC (I-TLB
invalidates) and VM_HUGETLB (large TLB invalidate) are used.

Therefore, track VM_EXEC and VM_HUGETLB in two more bits, and create a
'fake' VMA.

This allows architectures that have a reasonably efficient
flush_tlb_range() to not require any additional effort.

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: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
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: Nick Piggin <npiggin@gmail.com>
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 e7fd28a7

arch/arm64/include/asm/tlb.h

+1 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ static inline void __tlb_remove_table(void *_table) 
	free_page_and_swap_cache((struct page *)_table);

}



#define tlb_flush tlb_flush

static void tlb_flush(struct mmu_gather *tlb);



#include <asm-generic/tlb.h>

arch/powerpc/include/asm/tlb.h

+1 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#define tlb_end_vma(tlb, vma)	do { } while (0)

#define __tlb_remove_tlb_entry	__tlb_remove_tlb_entry



#define tlb_flush tlb_flush

extern void tlb_flush(struct mmu_gather *tlb);



/* Get the generic bits... */

arch/riscv/include/asm/tlb.h

+1 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ struct mmu_gather; 


static void tlb_flush(struct mmu_gather *tlb);



#define tlb_flush tlb_flush

#include <asm-generic/tlb.h>



static inline void tlb_flush(struct mmu_gather *tlb)

arch/x86/include/asm/tlb.h

+1 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#define tlb_end_vma(tlb, vma) do { } while (0)

#define __tlb_remove_tlb_entry(tlb, ptep, address) do { } while (0)



#define tlb_flush tlb_flush

static inline void tlb_flush(struct mmu_gather *tlb);



#include <asm-generic/tlb.h>

include/asm-generic/tlb.h

+83 −12
Original line number Diff line number Diff line
@@ -95,7 +95,7 @@ 
 *    flush the entire TLB irrespective of the range. For instance

 *    x86-PAE needs this when changing top-level entries.

 *

 * And requires the architecture to provide and implement tlb_flush().

 * And allows the architecture to provide and implement tlb_flush():

 *

 * tlb_flush() may, in addition to the above mentioned mmu_gather fields, make

 * use of:
@@ -111,7 +111,10 @@ 
 *

 *  - tlb_get_unmap_shift() / tlb_get_unmap_size()

 *

 *    returns the smallest TLB entry size unmapped in this range

 *    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.

 *

 * Additionally there are a few opt-in features:

 *
@@ -245,6 +248,12 @@ struct mmu_gather { 
	unsigned int		cleared_puds : 1;

	unsigned int		cleared_p4ds : 1;



	/*

	 * tracks VM_EXEC | VM_HUGETLB in tlb_start_vma

	 */

	unsigned int		vma_exec : 1;

	unsigned int		vma_huge : 1;



	unsigned int		batch_count;



	struct mmu_gather_batch *active;
@@ -286,8 +295,59 @@ static inline void __tlb_reset_range(struct mmu_gather *tlb) 
	tlb->cleared_pmds = 0;

	tlb->cleared_puds = 0;

	tlb->cleared_p4ds = 0;

	/*

	 * Do not reset mmu_gather::vma_* fields here, we do not

	 * call into tlb_start_vma() again to set them if there is an

	 * intermediate flush.

	 */

}



#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



static inline void tlb_flush(struct mmu_gather *tlb)

{

	if (tlb->fullmm || tlb->need_flush_all) {

		flush_tlb_mm(tlb->mm);

	} else if (tlb->end) {

		struct vm_area_struct vma = {

			.vm_mm = tlb->mm,

			.vm_flags = (tlb->vma_exec ? VM_EXEC    : 0) |

				    (tlb->vma_huge ? VM_HUGETLB : 0),

		};



		flush_tlb_range(&vma, tlb->start, tlb->end);

	}

}



static inline void

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

{

	/*

	 * flush_tlb_range() implementations that look at VM_HUGETLB (tile,

	 * mips-4k) flush only large pages.

	 *

	 * flush_tlb_range() implementations that flush I-TLB also flush D-TLB

	 * (tile, xtensa, arm), so it's ok to just add VM_EXEC to an existing

	 * range.

	 *

	 * We rely on tlb_end_vma() to issue a flush, such that when we reset

	 * these values the batch is empty.

	 */

	tlb->vma_huge = !!(vma->vm_flags & VM_HUGETLB);

	tlb->vma_exec = !!(vma->vm_flags & VM_EXEC);

}



#else



static inline void

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



#endif



static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)

{

	if (!tlb->end)
@@ -357,19 +417,30 @@ static inline unsigned long tlb_get_unmap_size(struct mmu_gather *tlb) 
 * the vmas are adjusted to only cover the region to be torn down.

 */

#ifndef tlb_start_vma

#define tlb_start_vma(tlb, vma)						\

do {									\

	if (!tlb->fullmm)						\

		flush_cache_range(vma, vma->vm_start, vma->vm_end);	\

} while (0)

static inline void tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)

{

	if (tlb->fullmm)

		return;



	tlb_update_vma_flags(tlb, vma);

	flush_cache_range(vma, vma->vm_start, vma->vm_end);

}

#endif



#ifndef tlb_end_vma

#define tlb_end_vma(tlb, vma)						\

do {									\

	if (!tlb->fullmm)						\

		tlb_flush_mmu_tlbonly(tlb);				\

} while (0)

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

{

	if (tlb->fullmm)

		return;



	/*

	 * Do a TLB flush and reset the range at VMA boundaries; this avoids

	 * the ranges growing with the unused space between consecutive VMAs,

	 * but also the mmu_gather::vma_* flags from tlb_start_vma() rely on

	 * this.

	 */

	tlb_flush_mmu_tlbonly(tlb);

}

#endif



#ifndef __tlb_remove_tlb_entry

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