1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
|
/*
* linux/arch/arm/mm/flush.c
*
* Copyright (C) 1995-2002 Russell King
*
* 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.
*/
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <asm/cacheflush.h>
#include <asm/system.h>
#include <asm/tlbflush.h>
#ifdef CONFIG_CPU_CACHE_VIPT
#define ALIAS_FLUSH_START 0xffff4000
#define TOP_PTE(x) pte_offset_kernel(top_pmd, x)
static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr)
{
unsigned long to = ALIAS_FLUSH_START + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
set_pte(TOP_PTE(to), pfn_pte(pfn, PAGE_KERNEL));
flush_tlb_kernel_page(to);
asm( "mcrr p15, 0, %1, %0, c14\n"
" mcrr p15, 0, %1, %0, c5\n"
:
: "r" (to), "r" (to + PAGE_SIZE - L1_CACHE_BYTES)
: "cc");
}
void flush_cache_mm(struct mm_struct *mm)
{
if (cache_is_vivt()) {
if (cpu_isset(smp_processor_id(), mm->cpu_vm_mask))
__cpuc_flush_user_all();
return;
}
if (cache_is_vipt_aliasing()) {
asm( "mcr p15, 0, %0, c7, c14, 0\n"
" mcr p15, 0, %0, c7, c5, 0\n"
" mcr p15, 0, %0, c7, c10, 4"
:
: "r" (0)
: "cc");
}
}
void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
{
if (cache_is_vivt()) {
if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask))
__cpuc_flush_user_range(start & PAGE_MASK, PAGE_ALIGN(end),
vma->vm_flags);
return;
}
if (cache_is_vipt_aliasing()) {
asm( "mcr p15, 0, %0, c7, c14, 0\n"
" mcr p15, 0, %0, c7, c5, 0\n"
" mcr p15, 0, %0, c7, c10, 4"
:
: "r" (0)
: "cc");
}
}
void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsigned long pfn)
{
if (cache_is_vivt()) {
if (cpu_isset(smp_processor_id(), vma->vm_mm->cpu_vm_mask)) {
unsigned long addr = user_addr & PAGE_MASK;
__cpuc_flush_user_range(addr, addr + PAGE_SIZE, vma->vm_flags);
}
return;
}
if (cache_is_vipt_aliasing())
flush_pfn_alias(pfn, user_addr);
}
#else
#define flush_pfn_alias(pfn,vaddr) do { } while (0)
#endif
void __flush_dcache_page(struct address_space *mapping, struct page *page)
{
/*
* Writeback any data associated with the kernel mapping of this
* page. This ensures that data in the physical page is mutually
* coherent with the kernels mapping.
*/
__cpuc_flush_dcache_page(page_address(page));
/*
* If this is a page cache page, and we have an aliasing VIPT cache,
* we only need to do one flush - which would be at the relevant
* userspace colour, which is congruent with page->index.
*/
if (mapping && cache_is_vipt_aliasing())
flush_pfn_alias(page_to_pfn(page),
page->index << PAGE_CACHE_SHIFT);
}
static void __flush_dcache_aliases(struct address_space *mapping, struct page *page)
{
struct mm_struct *mm = current->active_mm;
struct vm_area_struct *mpnt;
struct prio_tree_iter iter;
pgoff_t pgoff;
/*
* There are possible user space mappings of this page:
* - VIVT cache: we need to also write back and invalidate all user
* data in the current VM view associated with this page.
* - aliasing VIPT: we only need to find one mapping of this page.
*/
pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
flush_dcache_mmap_lock(mapping);
vma_prio_tree_foreach(mpnt, &iter, &mapping->i_mmap, pgoff, pgoff) {
unsigned long offset;
/*
* If this VMA is not in our MM, we can ignore it.
*/
if (mpnt->vm_mm != mm)
continue;
if (!(mpnt->vm_flags & VM_MAYSHARE))
continue;
offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
flush_cache_page(mpnt, mpnt->vm_start + offset, page_to_pfn(page));
}
flush_dcache_mmap_unlock(mapping);
}
/*
* Ensure cache coherency between kernel mapping and userspace mapping
* of this page.
*
* We have three cases to consider:
* - VIPT non-aliasing cache: fully coherent so nothing required.
* - VIVT: fully aliasing, so we need to handle every alias in our
* current VM view.
* - VIPT aliasing: need to handle one alias in our current VM view.
*
* If we need to handle aliasing:
* If the page only exists in the page cache and there are no user
* space mappings, we can be lazy and remember that we may have dirty
* kernel cache lines for later. Otherwise, we assume we have
* aliasing mappings.
*
* Note that we disable the lazy flush for SMP.
*/
void flush_dcache_page(struct page *page)
{
struct address_space *mapping = page_mapping(page);
#ifndef CONFIG_SMP
if (mapping && !mapping_mapped(mapping))
set_bit(PG_dcache_dirty, &page->flags);
else
#endif
{
__flush_dcache_page(mapping, page);
if (mapping && cache_is_vivt())
__flush_dcache_aliases(mapping, page);
}
}
EXPORT_SYMBOL(flush_dcache_page);
|
