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
14void *kmap(struct page *page)
15{
16	might_sleep();
17	if (!PageHighMem(page))
18		return page_address(page);
19	return kmap_high(page);
20}
21
22EXPORT_SYMBOL(kmap);
23
24void kunmap(struct page *page)
25{
26	if (in_interrupt())
27		BUG();
28	if (!PageHighMem(page))
29		return;
30	kunmap_high(page);
31}
32
33EXPORT_SYMBOL(kunmap);
34
35struct page *kmap_atomic_to_page(void *ptr)
36{
37	return virt_to_page(ptr);
38}
39
40void *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(4, paddr, 6);
54	case 1:		return __kmap_atomic_primary(5, paddr, 7);
55	case 2:		return __kmap_atomic_primary(6, paddr, 8);
56	case 3:		return __kmap_atomic_primary(7, paddr, 9);
57	case 4:		return __kmap_atomic_primary(8, 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}
67EXPORT_SYMBOL(kmap_atomic);
68
69void __kunmap_atomic(void *kvaddr)
70{
71	int type = kmap_atomic_idx();
72	switch (type) {
73	case 0:		__kunmap_atomic_primary(4, 6);	break;
74	case 1:		__kunmap_atomic_primary(5, 7);	break;
75	case 2:		__kunmap_atomic_primary(6, 8);	break;
76	case 3:		__kunmap_atomic_primary(7, 9);	break;
77	case 4:		__kunmap_atomic_primary(8, 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}
89EXPORT_SYMBOL(__kunmap_atomic);