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1da177e4 LT |
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 Terrabyte 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/interrupt.h> | |
24 | #include <asm/fixmap.h> | |
25 | #include <asm/vaddrs.h> | |
26 | #include <asm/kmap_types.h> | |
27 | #include <asm/pgtable.h> | |
28 | ||
29 | /* declarations for highmem.c */ | |
30 | extern unsigned long highstart_pfn, highend_pfn; | |
31 | ||
32 | extern pte_t *kmap_pte; | |
33 | extern pgprot_t kmap_prot; | |
34 | extern pte_t *pkmap_page_table; | |
35 | ||
36 | extern void kmap_init(void) __init; | |
37 | ||
38 | /* | |
39 | * Right now we initialize only a single pte table. It can be extended | |
40 | * easily, subsequent pte tables have to be allocated in one physical | |
41 | * chunk of RAM. Currently the simplest way to do this is to align the | |
42 | * pkmap region on a pagetable boundary (4MB). | |
43 | */ | |
44 | #define LAST_PKMAP 1024 | |
45 | #define PKMAP_SIZE (LAST_PKMAP << PAGE_SHIFT) | |
46 | #define PKMAP_BASE PMD_ALIGN(SRMMU_NOCACHE_VADDR + (SRMMU_MAX_NOCACHE_PAGES << PAGE_SHIFT)) | |
47 | ||
48 | #define LAST_PKMAP_MASK (LAST_PKMAP - 1) | |
49 | #define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT) | |
50 | #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) | |
51 | ||
52 | #define PKMAP_END (PKMAP_ADDR(LAST_PKMAP)) | |
53 | ||
54 | extern void *kmap_high(struct page *page); | |
55 | extern void kunmap_high(struct page *page); | |
56 | ||
57 | static inline void *kmap(struct page *page) | |
58 | { | |
59 | BUG_ON(in_interrupt()); | |
60 | if (!PageHighMem(page)) | |
61 | return page_address(page); | |
62 | return kmap_high(page); | |
63 | } | |
64 | ||
65 | static inline void kunmap(struct page *page) | |
66 | { | |
67 | BUG_ON(in_interrupt()); | |
68 | if (!PageHighMem(page)) | |
69 | return; | |
70 | kunmap_high(page); | |
71 | } | |
72 | ||
73 | extern void *kmap_atomic(struct page *page, enum km_type type); | |
74 | extern void kunmap_atomic(void *kvaddr, enum km_type type); | |
75 | extern struct page *kmap_atomic_to_page(void *vaddr); | |
76 | ||
77 | #define flush_cache_kmaps() flush_cache_all() | |
78 | ||
79 | #endif /* __KERNEL__ */ | |
80 | ||
81 | #endif /* _ASM_HIGHMEM_H */ |