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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | /* |
3 | * highmem.h: virtual kernel memory mappings for high memory | |
4 | * | |
5 | * Used in CONFIG_HIGHMEM systems for memory pages which | |
6 | * are not addressable by direct kernel virtual addresses. | |
7 | * | |
8 | * Copyright (C) 1999 Gerhard Wichert, Siemens AG | |
9 | * Gerhard.Wichert@pdb.siemens.de | |
10 | * | |
11 | * | |
12 | * Redesigned the x86 32-bit VM architecture to deal with | |
13 | * up to 16 Terrabyte physical memory. With current x86 CPUs | |
14 | * we now support up to 64 Gigabytes physical RAM. | |
15 | * | |
16 | * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com> | |
17 | */ | |
18 | ||
19 | #ifndef _ASM_HIGHMEM_H | |
20 | #define _ASM_HIGHMEM_H | |
21 | ||
22 | #ifdef __KERNEL__ | |
23 | ||
24 | #include <linux/interrupt.h> | |
1da177e4 LT |
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 | ||
1da177e4 LT |
32 | extern pgprot_t kmap_prot; |
33 | extern pte_t *pkmap_page_table; | |
34 | ||
f05a6865 | 35 | void kmap_init(void) __init; |
1da177e4 LT |
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. Currently the simplest way to do this is to align the | |
41 | * pkmap region on a pagetable boundary (4MB). | |
42 | */ | |
43 | #define LAST_PKMAP 1024 | |
44 | #define PKMAP_SIZE (LAST_PKMAP << PAGE_SHIFT) | |
45 | #define PKMAP_BASE PMD_ALIGN(SRMMU_NOCACHE_VADDR + (SRMMU_MAX_NOCACHE_PAGES << PAGE_SHIFT)) | |
46 | ||
47 | #define LAST_PKMAP_MASK (LAST_PKMAP - 1) | |
48 | #define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT) | |
49 | #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) | |
50 | ||
51 | #define PKMAP_END (PKMAP_ADDR(LAST_PKMAP)) | |
52 | ||
f05a6865 SR |
53 | void *kmap_high(struct page *page); |
54 | void kunmap_high(struct page *page); | |
1da177e4 LT |
55 | |
56 | static inline void *kmap(struct page *page) | |
57 | { | |
58 | BUG_ON(in_interrupt()); | |
59 | if (!PageHighMem(page)) | |
60 | return page_address(page); | |
61 | return kmap_high(page); | |
62 | } | |
63 | ||
64 | static inline void kunmap(struct page *page) | |
65 | { | |
66 | BUG_ON(in_interrupt()); | |
67 | if (!PageHighMem(page)) | |
68 | return; | |
69 | kunmap_high(page); | |
70 | } | |
71 | ||
f05a6865 SR |
72 | void *kmap_atomic(struct page *page); |
73 | void __kunmap_atomic(void *kvaddr); | |
1da177e4 LT |
74 | |
75 | #define flush_cache_kmaps() flush_cache_all() | |
76 | ||
77 | #endif /* __KERNEL__ */ | |
78 | ||
79 | #endif /* _ASM_HIGHMEM_H */ |