summaryrefslogtreecommitdiff
path: root/arch/csky/mm/highmem.c
blob: 4a3c273bc8b95e84ef28b73d275b873fcc1f6b85 (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
139
140
141
// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.

#include <linux/module.h>
#include <linux/highmem.h>
#include <linux/smp.h>
#include <linux/memblock.h>
#include <asm/fixmap.h>
#include <asm/tlbflush.h>
#include <asm/cacheflush.h>

static pte_t *kmap_pte;

unsigned long highstart_pfn, highend_pfn;

void kmap_flush_tlb(unsigned long addr)
{
	flush_tlb_one(addr);
}
EXPORT_SYMBOL(kmap_flush_tlb);

EXPORT_SYMBOL(kmap);

void kunmap(struct page *page)
{
	might_sleep();
	if (!PageHighMem(page))
		return;
	kunmap_high(page);
}
EXPORT_SYMBOL(kunmap);

void *kmap_atomic(struct page *page)
{
	unsigned long vaddr;
	int idx, type;

	preempt_disable();
	pagefault_disable();
	if (!PageHighMem(page))
		return page_address(page);

	type = kmap_atomic_idx_push();
	idx = type + KM_TYPE_NR*smp_processor_id();
	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
#ifdef CONFIG_DEBUG_HIGHMEM
	BUG_ON(!pte_none(*(kmap_pte - idx)));
#endif
	set_pte(kmap_pte-idx, mk_pte(page, PAGE_KERNEL));
	flush_tlb_one((unsigned long)vaddr);

	return (void *)vaddr;
}
EXPORT_SYMBOL(kmap_atomic);

void __kunmap_atomic(void *kvaddr)
{
	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
	int idx;

	if (vaddr < FIXADDR_START)
		goto out;

#ifdef CONFIG_DEBUG_HIGHMEM
	idx = KM_TYPE_NR*smp_processor_id() + kmap_atomic_idx();

	BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));

	pte_clear(&init_mm, vaddr, kmap_pte - idx);
	flush_tlb_one(vaddr);
#else
	(void) idx; /* to kill a warning */
#endif
	kmap_atomic_idx_pop();
out:
	pagefault_enable();
	preempt_enable();
}
EXPORT_SYMBOL(__kunmap_atomic);

/*
 * This is the same as kmap_atomic() but can map memory that doesn't
 * have a struct page associated with it.
 */
void *kmap_atomic_pfn(unsigned long pfn)
{
	unsigned long vaddr;
	int idx, type;

	pagefault_disable();

	type = kmap_atomic_idx_push();
	idx = type + KM_TYPE_NR*smp_processor_id();
	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
	set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
	flush_tlb_one(vaddr);

	return (void *) vaddr;
}

struct page *kmap_atomic_to_page(void *ptr)
{
	unsigned long idx, vaddr = (unsigned long)ptr;
	pte_t *pte;

	if (vaddr < FIXADDR_START)
		return virt_to_page(ptr);

	idx = virt_to_fix(vaddr);
	pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
	return pte_page(*pte);
}

static void __init kmap_pages_init(void)
{
	unsigned long vaddr;
	pgd_t *pgd;
	pmd_t *pmd;
	pud_t *pud;
	pte_t *pte;

	vaddr = PKMAP_BASE;
	fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);

	pgd = swapper_pg_dir + __pgd_offset(vaddr);
	pud = (pud_t *)pgd;
	pmd = pmd_offset(pud, vaddr);
	pte = pte_offset_kernel(pmd, vaddr);
	pkmap_page_table = pte;
}

void __init kmap_init(void)
{
	unsigned long vaddr;

	kmap_pages_init();

	vaddr = __fix_to_virt(FIX_KMAP_BEGIN);

	kmap_pte = pte_offset_kernel((pmd_t *)pgd_offset_k(vaddr), vaddr);
}