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(struct page * page)35 void *kmap_atomic(struct page *page)
36 {
37 unsigned long paddr;
38 int type;
39
40 preempt_disable();
41 pagefault_disable();
42 type = kmap_atomic_idx_push();
43 paddr = page_to_phys(page);
44
45 switch (type) {
46 /*
47 * The first 4 primary maps are reserved for architecture code
48 */
49 case 0: return __kmap_atomic_primary(0, paddr, 6);
50 case 1: return __kmap_atomic_primary(0, paddr, 7);
51 case 2: return __kmap_atomic_primary(0, paddr, 8);
52 case 3: return __kmap_atomic_primary(0, paddr, 9);
53 case 4: return __kmap_atomic_primary(0, paddr, 10);
54
55 case 5 ... 5 + NR_TLB_LINES - 1:
56 return __kmap_atomic_secondary(type - 5, paddr);
57
58 default:
59 BUG();
60 return NULL;
61 }
62 }
63 EXPORT_SYMBOL(kmap_atomic);
64
__kunmap_atomic(void * kvaddr)65 void __kunmap_atomic(void *kvaddr)
66 {
67 int type = kmap_atomic_idx();
68 switch (type) {
69 case 0: __kunmap_atomic_primary(0, 6); break;
70 case 1: __kunmap_atomic_primary(0, 7); break;
71 case 2: __kunmap_atomic_primary(0, 8); break;
72 case 3: __kunmap_atomic_primary(0, 9); break;
73 case 4: __kunmap_atomic_primary(0, 10); break;
74
75 case 5 ... 5 + NR_TLB_LINES - 1:
76 __kunmap_atomic_secondary(type - 5, kvaddr);
77 break;
78
79 default:
80 BUG();
81 }
82 kmap_atomic_idx_pop();
83 pagefault_enable();
84 preempt_enable();
85 }
86 EXPORT_SYMBOL(__kunmap_atomic);
87