summaryrefslogtreecommitdiff
path: root/arch/arm/mm/copypage-v6.c
blob: a1a71f36d8502758b4fb1f69ad2e79cf96fd1a5b (plain)
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
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/arch/arm/mm/copypage-v6.c
 *
 *  Copyright (C) 2002 Deep Blue Solutions Ltd, All Rights Reserved.
 */
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>

#include <asm/shmparam.h>
#include <asm/tlbflush.h>
#include <asm/cacheflush.h>
#include <asm/cachetype.h>

#include "mm.h"

#if SHMLBA > 16384
#error FIX ME
#endif

static DEFINE_RAW_SPINLOCK(v6_lock);

/*
 * Copy the user page.  No aliasing to deal with so we can just
 * attack the kernel's existing mapping of these pages.
 */
static void v6_copy_user_highpage_nonaliasing(struct page *to,
	struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
{
	void *kto, *kfrom;

	kfrom = kmap_atomic(from);
	kto = kmap_atomic(to);
	copy_page(kto, kfrom);
	kunmap_atomic(kto);
	kunmap_atomic(kfrom);
}

/*
 * Clear the user page.  No aliasing to deal with so we can just
 * attack the kernel's existing mapping of this page.
 */
static void v6_clear_user_highpage_nonaliasing(struct page *page, unsigned long vaddr)
{
	void *kaddr = kmap_atomic(page);
	clear_page(kaddr);
	kunmap_atomic(kaddr);
}

/*
 * Discard data in the kernel mapping for the new page.
 * FIXME: needs this MCRR to be supported.
 */
static void discard_old_kernel_data(void *kto)
{
	__asm__("mcrr	p15, 0, %1, %0, c6	@ 0xec401f06"
	   :
	   : "r" (kto),
	     "r" ((unsigned long)kto + PAGE_SIZE - 1)
	   : "cc");
}

/*
 * Copy the page, taking account of the cache colour.
 */
static void v6_copy_user_highpage_aliasing(struct page *to,
	struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
{
	struct folio *src = page_folio(from);
	unsigned int offset = CACHE_COLOUR(vaddr);
	unsigned long kfrom, kto;

	if (!test_and_set_bit(PG_dcache_clean, &src->flags))
		__flush_dcache_folio(folio_flush_mapping(src), src);

	/* FIXME: not highmem safe */
	discard_old_kernel_data(page_address(to));

	/*
	 * Now copy the page using the same cache colour as the
	 * pages ultimate destination.
	 */
	raw_spin_lock(&v6_lock);

	kfrom = COPYPAGE_V6_FROM + (offset << PAGE_SHIFT);
	kto   = COPYPAGE_V6_TO + (offset << PAGE_SHIFT);

	set_top_pte(kfrom, mk_pte(from, PAGE_KERNEL));
	set_top_pte(kto, mk_pte(to, PAGE_KERNEL));

	copy_page((void *)kto, (void *)kfrom);

	raw_spin_unlock(&v6_lock);
}

/*
 * Clear the user page.  We need to deal with the aliasing issues,
 * so remap the kernel page into the same cache colour as the user
 * page.
 */
static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr)
{
	unsigned long to = COPYPAGE_V6_TO + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);

	/* FIXME: not highmem safe */
	discard_old_kernel_data(page_address(page));

	/*
	 * Now clear the page using the same cache colour as
	 * the pages ultimate destination.
	 */
	raw_spin_lock(&v6_lock);

	set_top_pte(to, mk_pte(page, PAGE_KERNEL));
	clear_page((void *)to);

	raw_spin_unlock(&v6_lock);
}

struct cpu_user_fns v6_user_fns __initdata = {
	.cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing,
	.cpu_copy_user_highpage	= v6_copy_user_highpage_nonaliasing,
};

static int __init v6_userpage_init(void)
{
	if (cache_is_vipt_aliasing()) {
		cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing;
		cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing;
	}

	return 0;
}

core_initcall(v6_userpage_init);