1#include <linux/export.h>
2#include <linux/highmem.h>
3#include <linux/sched.h>
4#include <linux/smp.h>
5#include <linux/interrupt.h>
6#include <asm/fixmap.h>
7#include <asm/tlbflush.h>
8
9static pte_t *kmap_pte;
10
11unsigned long highstart_pfn, highend_pfn;
12
13void *kmap(struct page *page)
14{
15 might_sleep();
16 if (!PageHighMem(page))
17 return page_address(page);
18 return kmap_high(page);
19}
20EXPORT_SYMBOL(kmap);
21
22void kunmap(struct page *page)
23{
24 BUG_ON(in_interrupt());
25 if (!PageHighMem(page))
26 return;
27 kunmap_high(page);
28}
29EXPORT_SYMBOL(kunmap);
30
31
32
33
34
35
36
37
38
39
40void *kmap_atomic(struct page *page)
41{
42 enum fixed_addresses idx;
43 unsigned long vaddr;
44 int type;
45
46 preempt_disable();
47 pagefault_disable();
48 if (!PageHighMem(page))
49 return page_address(page);
50
51 type = kmap_atomic_idx_push();
52 idx = type + KM_TYPE_NR * smp_processor_id();
53 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
54#ifdef CONFIG_DEBUG_HIGHMEM
55 BUG_ON(!pte_none(*(kmap_pte - idx)));
56#endif
57 set_pte(kmap_pte - idx, mk_pte(page, PAGE_KERNEL));
58
59 return (void *)vaddr;
60}
61EXPORT_SYMBOL(kmap_atomic);
62
63void __kunmap_atomic(void *kvaddr)
64{
65 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
66 int idx, type;
67
68 if (kvaddr >= (void *)FIXADDR_START) {
69 type = kmap_atomic_idx();
70 idx = type + KM_TYPE_NR * smp_processor_id();
71
72
73
74
75
76
77
78 pte_clear(&init_mm, vaddr, kmap_pte-idx);
79 flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE);
80
81 kmap_atomic_idx_pop();
82 }
83
84 pagefault_enable();
85 preempt_enable();
86}
87EXPORT_SYMBOL(__kunmap_atomic);
88
89
90
91
92
93void *kmap_atomic_pfn(unsigned long pfn)
94{
95 enum fixed_addresses idx;
96 unsigned long vaddr;
97 int type;
98
99 preempt_disable();
100 pagefault_disable();
101
102 type = kmap_atomic_idx_push();
103 idx = type + KM_TYPE_NR * smp_processor_id();
104 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
105#ifdef CONFIG_DEBUG_HIGHMEM
106 BUG_ON(!pte_none(*(kmap_pte - idx)));
107#endif
108 set_pte(kmap_pte - idx, pfn_pte(pfn, PAGE_KERNEL));
109 flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE);
110
111 return (void *)vaddr;
112}
113
114void __init kmap_init(void)
115{
116 unsigned long kmap_vstart;
117
118
119 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
120 kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
121}
122