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/init.h>
23#include <linux/interrupt.h>
24#include <linux/uaccess.h>
25#include <asm/kmap_types.h>
26
27/* undef for production */
28#define HIGHMEM_DEBUG 1
29
30/* declarations for highmem.c */
31extern unsigned long highstart_pfn, highend_pfn;
32
33extern pte_t *kmap_pte;
34extern pgprot_t kmap_prot;
35extern pte_t *pkmap_page_table;
36
37/*
38 * Right now we initialize only a single pte table. It can be extended
39 * easily, subsequent pte tables have to be allocated in one physical
40 * chunk of RAM.
41 */
42#define PKMAP_BASE (0xfe000000UL)
43#define LAST_PKMAP 1024
44#define LAST_PKMAP_MASK (LAST_PKMAP-1)
45#define PKMAP_NR(virt)  ((virt-PKMAP_BASE) >> PAGE_SHIFT)
46#define PKMAP_ADDR(nr)  (PKMAP_BASE + ((nr) << PAGE_SHIFT))
47
48extern void * kmap_high(struct page *page);
49extern void kunmap_high(struct page *page);
50
51extern void *__kmap(struct page *page);
52extern void __kunmap(struct page *page);
53extern void *__kmap_atomic(struct page *page, enum km_type type);
54extern void __kunmap_atomic(void *kvaddr, enum km_type type);
55extern void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
56extern void *kmap_atomic_pfn_prot(unsigned long pfn, enum km_type type, pgprot_t prot);
57extern struct page *__kmap_atomic_to_page(void *ptr);
58
59#define kmap			__kmap
60#define kunmap			__kunmap
61#define kmap_atomic		__kmap_atomic
62#define kunmap_atomic		__kunmap_atomic
63#define kmap_atomic_to_page	__kmap_atomic_to_page
64
65#define flush_cache_kmaps()	flush_cache_all()
66
67#endif /* __KERNEL__ */
68
69#endif /* _ASM_HIGHMEM_H */
70