Commit 020c1427 authored by Catalin Marinas's avatar Catalin Marinas
Browse files

arm64: Convert asm/tlb.h to generic mmu_gather 



Over the past couple of years, the generic mmu_gather gained range
tracking - 597e1c35 (mm/mmu_gather: enable tlb flush range in generic
mmu_gather), 2b047252 (Fix TLB gather virtual address range
invalidation corner cases) - and tlb_fast_mode() has been removed -
29eb7782 (arch, mm: Remove tlb_fast_mode()).

The new mmu_gather structure is now suitable for arm64 and this patch
converts the arch asm/tlb.h to the generic code. One functional
difference is the shift_arg_pages() case where previously the code was
flushing the full mm (no tlb_start_vma call) but now it flushes the
range given to tlb_gather_mmu() (possibly slightly more efficient
previously).

Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
parent 22bd1c91

arch/arm64/include/asm/tlb.h

+20 −116
Original line number Diff line number Diff line
@@ -19,115 +19,44 @@ 
#ifndef __ASM_TLB_H

#define __ASM_TLB_H



#include <linux/pagemap.h>

#include <linux/swap.h>



#include <asm/pgalloc.h>

#include <asm/tlbflush.h>



#define MMU_GATHER_BUNDLE	8

#include <asm-generic/tlb.h>



/*

 * TLB handling.  This allows us to remove pages from the page

 * tables, and efficiently handle the TLB issues.

 */

struct mmu_gather {

	struct mm_struct	*mm;

	unsigned int		fullmm;

	struct vm_area_struct	*vma;

	unsigned long		start, end;

	unsigned long		range_start;

	unsigned long		range_end;

	unsigned int		nr;

	unsigned int		max;

	struct page		**pages;

	struct page		*local[MMU_GATHER_BUNDLE];

};



/*

 * This is unnecessarily complex.  There's three ways the TLB shootdown

 * code is used:

 * There's three ways the TLB shootdown code is used:

 *  1. Unmapping a range of vmas.  See zap_page_range(), unmap_region().

 *     tlb->fullmm = 0, and tlb_start_vma/tlb_end_vma will be called.

 *     tlb->vma will be non-NULL.

 *  2. Unmapping all vmas.  See exit_mmap().

 *     tlb->fullmm = 1, and tlb_start_vma/tlb_end_vma will be called.

 *     tlb->vma will be non-NULL.  Additionally, page tables will be freed.

 *     Page tables will be freed.

 *  3. Unmapping argument pages.  See shift_arg_pages().

 *     tlb->fullmm = 0, but tlb_start_vma/tlb_end_vma will not be called.

 *     tlb->vma will be NULL.

 */

static inline void tlb_flush(struct mmu_gather *tlb)

{

	if (tlb->fullmm || !tlb->vma)

	if (tlb->fullmm) {

		flush_tlb_mm(tlb->mm);

	else if (tlb->range_end > 0) {

		flush_tlb_range(tlb->vma, tlb->range_start, tlb->range_end);

		tlb->range_start = TASK_SIZE;

		tlb->range_end = 0;

	} else if (tlb->end > 0) {

		struct vm_area_struct vma = { .vm_mm = tlb->mm, };

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

		tlb->start = TASK_SIZE;

		tlb->end = 0;

	}

}



static inline void tlb_add_flush(struct mmu_gather *tlb, unsigned long addr)

{

	if (!tlb->fullmm) {

		if (addr < tlb->range_start)

			tlb->range_start = addr;

		if (addr + PAGE_SIZE > tlb->range_end)

			tlb->range_end = addr + PAGE_SIZE;

	}

}



static inline void __tlb_alloc_page(struct mmu_gather *tlb)

{

	unsigned long addr = __get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);



	if (addr) {

		tlb->pages = (void *)addr;

		tlb->max = PAGE_SIZE / sizeof(struct page *);

		tlb->start = min(tlb->start, addr);

		tlb->end = max(tlb->end, addr + PAGE_SIZE);

	}

}



static inline void tlb_flush_mmu(struct mmu_gather *tlb)

{

	tlb_flush(tlb);

	free_pages_and_swap_cache(tlb->pages, tlb->nr);

	tlb->nr = 0;

	if (tlb->pages == tlb->local)

		__tlb_alloc_page(tlb);

}



static inline void

tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end)

{

	tlb->mm = mm;

	tlb->fullmm = !(start | (end+1));

	tlb->start = start;

	tlb->end = end;

	tlb->vma = NULL;

	tlb->max = ARRAY_SIZE(tlb->local);

	tlb->pages = tlb->local;

	tlb->nr = 0;

	__tlb_alloc_page(tlb);

}



static inline void

tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)

{

	tlb_flush_mmu(tlb);



	/* keep the page table cache within bounds */

	check_pgt_cache();



	if (tlb->pages != tlb->local)

		free_pages((unsigned long)tlb->pages, 0);

}



/*

 * Memorize the range for the TLB flush.

 */

static inline void

tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep, unsigned long addr)

static inline void __tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep,

					  unsigned long addr)

{

	tlb_add_flush(tlb, addr);

}
@@ -137,36 +66,22 @@ tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep, unsigned long addr) 
 * case where we're doing a full MM flush.  When we're doing a munmap,

 * the vmas are adjusted to only cover the region to be torn down.

 */

static inline void

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

static inline void tlb_start_vma(struct mmu_gather *tlb,

				 struct vm_area_struct *vma)

{

	if (!tlb->fullmm) {

		tlb->vma = vma;

		tlb->range_start = TASK_SIZE;

		tlb->range_end = 0;

		tlb->start = TASK_SIZE;

		tlb->end = 0;

	}

}



static inline void

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

static inline void tlb_end_vma(struct mmu_gather *tlb,

			       struct vm_area_struct *vma)

{

	if (!tlb->fullmm)

		tlb_flush(tlb);

}



static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)

{

	tlb->pages[tlb->nr++] = page;

	VM_BUG_ON(tlb->nr > tlb->max);

	return tlb->max - tlb->nr;

}



static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)

{

	if (!__tlb_remove_page(tlb, page))

		tlb_flush_mmu(tlb);

}



static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,

				  unsigned long addr)

{
@@ -184,16 +99,5 @@ static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp, 
}

#endif



#define pte_free_tlb(tlb, ptep, addr)	__pte_free_tlb(tlb, ptep, addr)

#define pmd_free_tlb(tlb, pmdp, addr)	__pmd_free_tlb(tlb, pmdp, addr)

#define pud_free_tlb(tlb, pudp, addr)	pud_free((tlb)->mm, pudp)



#define tlb_migrate_finish(mm)		do { } while (0)



static inline void

tlb_remove_pmd_tlb_entry(struct mmu_gather *tlb, pmd_t *pmdp, unsigned long addr)

{

	tlb_add_flush(tlb, addr);

}



#endif

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