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