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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