linux/arch/arm/include/asm/tlb.h
Peter Zijlstra 0d6e24d430 asm-generic/tlb: provide MMU_GATHER_TABLE_FREE
As described in the comment, the correct order for freeing pages is:

 1) unhook page
 2) TLB invalidate page
 3) free page

This order equally applies to page directories.

Currently there are two correct options:

 - use tlb_remove_page(), when all page directores are full pages and
   there are no futher contraints placed by things like software
   walkers (HAVE_FAST_GUP).

 - use MMU_GATHER_RCU_TABLE_FREE and tlb_remove_table() when the
   architecture does not do IPI based TLB invalidate and has
   HAVE_FAST_GUP (or software TLB fill).

This however leaves architectures that don't have page based directories
but don't need RCU in a bind.  For those, provide MMU_GATHER_TABLE_FREE,
which provides the independent batching for directories without the
additional RCU freeing.

Link: http://lkml.kernel.org/r/20200116064531.483522-10-aneesh.kumar@linux.ibm.com
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-04 03:05:26 +00:00

69 lines
1.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* arch/arm/include/asm/tlb.h
*
* Copyright (C) 2002 Russell King
*
* Experimentation shows that on a StrongARM, it appears to be faster
* to use the "invalidate whole tlb" rather than "invalidate single
* tlb" for this.
*
* This appears true for both the process fork+exit case, as well as
* the munmap-large-area case.
*/
#ifndef __ASMARM_TLB_H
#define __ASMARM_TLB_H
#include <asm/cacheflush.h>
#ifndef CONFIG_MMU
#include <linux/pagemap.h>
#define tlb_flush(tlb) ((void) tlb)
#include <asm-generic/tlb.h>
#else /* !CONFIG_MMU */
#include <linux/swap.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
static inline void __tlb_remove_table(void *_table)
{
free_page_and_swap_cache((struct page *)_table);
}
#include <asm-generic/tlb.h>
static inline void
__pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, unsigned long addr)
{
pgtable_pte_page_dtor(pte);
#ifndef CONFIG_ARM_LPAE
/*
* With the classic ARM MMU, a pte page has two corresponding pmd
* entries, each covering 1MB.
*/
addr = (addr & PMD_MASK) + SZ_1M;
__tlb_adjust_range(tlb, addr - PAGE_SIZE, 2 * PAGE_SIZE);
#endif
tlb_remove_table(tlb, pte);
}
static inline void
__pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp, unsigned long addr)
{
#ifdef CONFIG_ARM_LPAE
struct page *page = virt_to_page(pmdp);
tlb_remove_table(tlb, page);
#endif
}
#endif /* CONFIG_MMU */
#endif