1 /* highmem.c: arch-specific highmem stuff
2 *
3 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11 #include <linux/highmem.h>
12 #include <linux/module.h>
13
kmap(struct page * page)14 void *kmap(struct page *page)
15 {
16 might_sleep();
17 if (!PageHighMem(page))
18 return page_address(page);
19 return kmap_high(page);
20 }
21
22 EXPORT_SYMBOL(kmap);
23
kunmap(struct page * page)24 void kunmap(struct page *page)
25 {
26 if (in_interrupt())
27 BUG();
28 if (!PageHighMem(page))
29 return;
30 kunmap_high(page);
31 }
32
33 EXPORT_SYMBOL(kunmap);
34
kmap_atomic_to_page(void * ptr)35 struct page *kmap_atomic_to_page(void *ptr)
36 {
37 return virt_to_page(ptr);
38 }
39
kmap_atomic(struct page * page)40 void *kmap_atomic(struct page *page)
41 {
42 unsigned long paddr;
43 int type;
44
45 pagefault_disable();
46 type = kmap_atomic_idx_push();
47 paddr = page_to_phys(page);
48
49 switch (type) {
50 /*
51 * The first 4 primary maps are reserved for architecture code
52 */
53 case 0: return __kmap_atomic_primary(0, paddr, 6);
54 case 1: return __kmap_atomic_primary(0, paddr, 7);
55 case 2: return __kmap_atomic_primary(0, paddr, 8);
56 case 3: return __kmap_atomic_primary(0, paddr, 9);
57 case 4: return __kmap_atomic_primary(0, paddr, 10);
58
59 case 5 ... 5 + NR_TLB_LINES - 1:
60 return __kmap_atomic_secondary(type - 5, paddr);
61
62 default:
63 BUG();
64 return NULL;
65 }
66 }
67 EXPORT_SYMBOL(kmap_atomic);
68
__kunmap_atomic(void * kvaddr)69 void __kunmap_atomic(void *kvaddr)
70 {
71 int type = kmap_atomic_idx();
72 switch (type) {
73 case 0: __kunmap_atomic_primary(0, 6); break;
74 case 1: __kunmap_atomic_primary(0, 7); break;
75 case 2: __kunmap_atomic_primary(0, 8); break;
76 case 3: __kunmap_atomic_primary(0, 9); break;
77 case 4: __kunmap_atomic_primary(0, 10); break;
78
79 case 5 ... 5 + NR_TLB_LINES - 1:
80 __kunmap_atomic_secondary(type - 5, kvaddr);
81 break;
82
83 default:
84 BUG();
85 }
86 kmap_atomic_idx_pop();
87 pagefault_enable();
88 }
89 EXPORT_SYMBOL(__kunmap_atomic);
90