tlb.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * This file contains the routines for TLB flushing.
  4 * On machines where the MMU uses a hash table to store virtual to
  5 * physical translations, these routines flush entries from the
  6 * hash table also.
  7 *  -- paulus
  8 *
  9 *  Derived from arch/ppc/mm/init.c:
 10 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 11 *
 12 *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
 13 *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
 14 *    Copyright (C) 1996 Paul Mackerras
 15 *
 16 *  Derived from "arch/i386/mm/init.c"
 17 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 18 */
 19
 20#include <linux/kernel.h>
 21#include <linux/mm.h>
 22#include <linux/init.h>
 23#include <linux/highmem.h>
 24#include <linux/pagemap.h>
 25#include <linux/export.h>
 26
 27#include <asm/tlbflush.h>
 28#include <asm/tlb.h>
 29
 30#include <mm/mmu_decl.h>
 31
 32/*
 33 * TLB flushing:
 34 *
 35 *  - flush_tlb_mm(mm) flushes the specified mm context TLB's
 36 *  - flush_tlb_page(vma, vmaddr) flushes one page
 37 *  - flush_tlb_range(vma, start, end) flushes a range of pages
 38 *  - flush_tlb_kernel_range(start, end) flushes kernel pages
 39 *
 40 * since the hardware hash table functions as an extension of the
 41 * tlb as far as the linux tables are concerned, flush it too.
 42 *    -- Cort
 43 */
 44
 45/*
 46 * For each address in the range, find the pte for the address
 47 * and check _PAGE_HASHPTE bit; if it is set, find and destroy
 48 * the corresponding HPTE.
 49 */
 50void hash__flush_range(struct mm_struct *mm, unsigned long start, unsigned long end)
 51{
 52	pmd_t *pmd;
 53	unsigned long pmd_end;
 54	int count;
 55	unsigned int ctx = mm->context.id;
 56
 57	start &= PAGE_MASK;
 58	if (start >= end)
 59		return;
 60	end = (end - 1) | ~PAGE_MASK;
 61	pmd = pmd_off(mm, start);
 62	for (;;) {
 63		pmd_end = ((start + PGDIR_SIZE) & PGDIR_MASK) - 1;
 64		if (pmd_end > end)
 65			pmd_end = end;
 66		if (!pmd_none(*pmd)) {
 67			count = ((pmd_end - start) >> PAGE_SHIFT) + 1;
 68			flush_hash_pages(ctx, start, pmd_val(*pmd), count);
 69		}
 70		if (pmd_end == end)
 71			break;
 72		start = pmd_end + 1;
 73		++pmd;
 74	}
 75}
 76EXPORT_SYMBOL(hash__flush_range);
 77
 78/*
 79 * Flush all the (user) entries for the address space described by mm.
 80 */
 81void hash__flush_tlb_mm(struct mm_struct *mm)
 82{
 83	struct vm_area_struct *mp;
 84	VMA_ITERATOR(vmi, mm, 0);
 85
 86	/*
 87	 * It is safe to iterate the vmas when called from dup_mmap,
 88	 * holding mmap_lock.  It would also be safe from unmap_region
 89	 * or exit_mmap, but not from vmtruncate on SMP - but it seems
 90	 * dup_mmap is the only SMP case which gets here.
 91	 */
 92	for_each_vma(vmi, mp)
 93		hash__flush_range(mp->vm_mm, mp->vm_start, mp->vm_end);
 94}
 95EXPORT_SYMBOL(hash__flush_tlb_mm);
 96
 97void hash__flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
 98{
 99	struct mm_struct *mm;
100	pmd_t *pmd;
101
102	mm = (vmaddr < TASK_SIZE)? vma->vm_mm: &init_mm;
103	pmd = pmd_off(mm, vmaddr);
104	if (!pmd_none(*pmd))
105		flush_hash_pages(mm->context.id, vmaddr, pmd_val(*pmd), 1);
106}
107EXPORT_SYMBOL(hash__flush_tlb_page);
108
109void hash__flush_gather(struct mmu_gather *tlb)
110{
111	if (tlb->fullmm || tlb->need_flush_all)
112		hash__flush_tlb_mm(tlb->mm);
113	else
114		hash__flush_range(tlb->mm, tlb->start, tlb->end);
115}
116EXPORT_SYMBOL(hash__flush_gather);