linux_kernel/arch/arm64/include/asm/tlb.h

/*
 * Based on arch/arm/include/asm/tlb.h
 *
 * Copyright (C) 2002 Russell King
 * Copyright (C) 2012 ARM Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef __ASM_TLB_H
#define __ASM_TLB_H

#define  __tlb_remove_pmd_tlb_entry __tlb_remove_pmd_tlb_entry

#include <asm-generic/tlb.h>

#include <linux/pagemap.h>
#include <linux/swap.h>

#ifdef CONFIG_HAVE_RCU_TABLE_FREE

#define tlb_remove_entry(tlb, entry)	tlb_remove_table(tlb, entry)
static inline void __tlb_remove_table(void *_table)
{
	free_page_and_swap_cache((struct page *)_table);
}
#else
#define tlb_remove_entry(tlb, entry)	tlb_remove_page(tlb, entry)
#endif /* CONFIG_HAVE_RCU_TABLE_FREE */

/*
 * 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.
 *  2. Unmapping all vmas.  See exit_mmap().
 *     tlb->fullmm = 1, and tlb_start_vma/tlb_end_vma will be called.
 *     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.
 */
static inline void tlb_flush(struct mmu_gather *tlb)
{
	if (tlb->fullmm) {
		flush_tlb_mm(tlb->mm);
	} 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) {
		tlb->start = min(tlb->start, addr);
		tlb->end = max(tlb->end, addr + PAGE_SIZE);
	}
}

/*
 * Memorize the range for the TLB flush.
 */
static inline void __tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep,
					  unsigned long addr)
{
	tlb_add_flush(tlb, addr);
}

/*
 * In the case of tlb vma handling, we can optimise these away in the
 * 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)
{
	if (!tlb->fullmm) {
		tlb->start = TASK_SIZE;
		tlb->end = 0;
	}
}

static inline void tlb_end_vma(struct mmu_gather *tlb,
			       struct vm_area_struct *vma)
{
	if (!tlb->fullmm)
		tlb_flush(tlb);
}

static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
				  unsigned long addr)
{
	pgtable_page_dtor(pte);
	tlb_add_flush(tlb, addr);
	tlb_remove_entry(tlb, pte);
}

#if CONFIG_ARM64_PGTABLE_LEVELS > 2
static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp,
				  unsigned long addr)
{
	tlb_add_flush(tlb, addr);
	tlb_remove_entry(tlb, virt_to_page(pmdp));
}
#endif

#if CONFIG_ARM64_PGTABLE_LEVELS > 3
static inline void __pud_free_tlb(struct mmu_gather *tlb, pud_t *pudp,
				  unsigned long addr)
{
	tlb_add_flush(tlb, addr);
	tlb_remove_entry(tlb, virt_to_page(pudp));
}
#endif

static inline void __tlb_remove_pmd_tlb_entry(struct mmu_gather *tlb, pmd_t *pmdp,
						unsigned long address)
{
	tlb_add_flush(tlb, address);
}

#endif