1/*
2 * highmem.h: virtual kernel memory mappings for high memory
3 *
4 * Used in CONFIG_HIGHMEM systems for memory pages which
5 * are not addressable by direct kernel virtual addresses.
6 *
7 * Copyright (C) 1999 Gerhard Wichert, Siemens AG
8 *		      Gerhard.Wichert@pdb.siemens.de
9 *
10 *
11 * Redesigned the x86 32-bit VM architecture to deal with
12 * up to 16 Terabyte physical memory. With current x86 CPUs
13 * we now support up to 64 Gigabytes physical RAM.
14 *
15 * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
16 */
17#ifndef _ASM_HIGHMEM_H
18#define _ASM_HIGHMEM_H
19
20#ifdef __KERNEL__
21
22#include <linux/interrupt.h>
23#include <linux/uaccess.h>
24#include <asm/kmap_types.h>
25
26/* undef for production */
27#define HIGHMEM_DEBUG 1
28
29/* declarations for highmem.c */
30extern unsigned long highstart_pfn, highend_pfn;
31
32extern pte_t *pkmap_page_table;
33
34/*
35 * Right now we initialize only a single pte table. It can be extended
36 * easily, subsequent pte tables have to be allocated in one physical
37 * chunk of RAM.
38 */
39#define LAST_PKMAP 1024
40#define LAST_PKMAP_MASK (LAST_PKMAP-1)
41#define PKMAP_NR(virt)	((virt-PKMAP_BASE) >> PAGE_SHIFT)
42#define PKMAP_ADDR(nr)	(PKMAP_BASE + ((nr) << PAGE_SHIFT))
43
44extern void * kmap_high(struct page *page);
45extern void kunmap_high(struct page *page);
46
47extern void *kmap(struct page *page);
48extern void kunmap(struct page *page);
49extern void *kmap_atomic(struct page *page);
50extern void __kunmap_atomic(void *kvaddr);
51extern void *kmap_atomic_pfn(unsigned long pfn);
52extern struct page *kmap_atomic_to_page(void *ptr);
53
54#define flush_cache_kmaps()	flush_cache_all()
55
56extern void kmap_init(void);
57
58#define kmap_prot PAGE_KERNEL
59
60#endif /* __KERNEL__ */
61
62#endif /* _ASM_HIGHMEM_H */
63