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 */
hash__flush_range(struct mm_struct * mm,unsigned long start,unsigned long end)50 void 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 }
76 EXPORT_SYMBOL(hash__flush_range);
77
78 /*
79 * Flush all the (user) entries for the address space described by mm.
80 */
hash__flush_tlb_mm(struct mm_struct * mm)81 void 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 }
95 EXPORT_SYMBOL(hash__flush_tlb_mm);
96
hash__flush_tlb_page(struct vm_area_struct * vma,unsigned long vmaddr)97 void 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 }
107 EXPORT_SYMBOL(hash__flush_tlb_page);
108