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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
18#ifndef _ASM_HIGHMEM_H
19#define _ASM_HIGHMEM_H
20
21#ifdef __KERNEL__
22
23#include <linux/config.h>
24#include <linux/interrupt.h>
25#include <linux/threads.h>
26#include <asm/kmap_types.h>
27#include <asm/tlbflush.h>
28
29/* declarations for highmem.c */
30extern unsigned long highstart_pfn, highend_pfn;
31
32extern pte_t *kmap_pte;
33extern pgprot_t kmap_prot;
34extern pte_t *pkmap_page_table;
35
36/*
37 * Right now we initialize only a single pte table. It can be extended
38 * easily, subsequent pte tables have to be allocated in one physical
39 * chunk of RAM.
40 */
41#ifdef CONFIG_X86_PAE
42#define LAST_PKMAP 512
43#else
44#define LAST_PKMAP 1024
45#endif
46/*
47 * Ordering is:
48 *
49 * FIXADDR_TOP
50 * fixed_addresses
51 * FIXADDR_START
52 * temp fixed addresses
53 * FIXADDR_BOOT_START
54 * Persistent kmap area
55 * PKMAP_BASE
56 * VMALLOC_END
57 * Vmalloc area
58 * VMALLOC_START
59 * high_memory
60 */
61#define PKMAP_BASE ( (FIXADDR_BOOT_START - PAGE_SIZE*(LAST_PKMAP + 1)) & PMD_MASK )
62#define LAST_PKMAP_MASK (LAST_PKMAP-1)
63#define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT)
64#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
65
66extern void * FASTCALL(kmap_high(struct page *page));
67extern void FASTCALL(kunmap_high(struct page *page));
68
69void *kmap(struct page *page);
70void kunmap(struct page *page);
71void *kmap_atomic(struct page *page, enum km_type type);
72void kunmap_atomic(void *kvaddr, enum km_type type);
73struct page *kmap_atomic_to_page(void *ptr);
74
75#define flush_cache_kmaps() do { } while (0)
76
77#endif /* __KERNEL__ */
78
79#endif /* _ASM_HIGHMEM_H */