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1da177e4 LT |
1 | /* |
2 | * fixmap.h: compile-time virtual memory allocation | |
3 | * | |
4 | * This file is subject to the terms and conditions of the GNU General Public | |
5 | * License. See the file "COPYING" in the main directory of this archive | |
6 | * for more details. | |
7 | * | |
8 | * Copyright (C) 1998 Ingo Molnar | |
9 | * | |
10 | * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 | |
11 | */ | |
12 | ||
13 | #ifndef _ASM_FIXMAP_H | |
14 | #define _ASM_FIXMAP_H | |
15 | ||
1da177e4 | 16 | #include <asm/page.h> |
565b60de | 17 | #include <spaces.h> |
1da177e4 LT |
18 | #ifdef CONFIG_HIGHMEM |
19 | #include <linux/threads.h> | |
20 | #include <asm/kmap_types.h> | |
21 | #endif | |
22 | ||
23 | /* | |
24 | * Here we define all the compile-time 'special' virtual | |
25 | * addresses. The point is to have a constant address at | |
26 | * compile time, but to set the physical address only | |
27 | * in the boot process. We allocate these special addresses | |
28 | * from the end of virtual memory (0xfffff000) backwards. | |
29 | * Also this lets us do fail-safe vmalloc(), we | |
30 | * can guarantee that these special addresses and | |
31 | * vmalloc()-ed addresses never overlap. | |
32 | * | |
33 | * these 'compile-time allocated' memory buffers are | |
34 | * fixed-size 4k pages. (or larger if used with an increment | |
35 | * highger than 1) use fixmap_set(idx,phys) to associate | |
36 | * physical memory with fixmap indices. | |
37 | * | |
38 | * TLB entries of such buffers will not be flushed across | |
39 | * task switches. | |
40 | */ | |
41 | ||
42 | /* | |
43 | * on UP currently we will have no trace of the fixmap mechanizm, | |
44 | * no page table allocations, etc. This might change in the | |
45 | * future, say framebuffers for the console driver(s) could be | |
46 | * fix-mapped? | |
47 | */ | |
48 | enum fixed_addresses { | |
f8829cae RB |
49 | #define FIX_N_COLOURS 8 |
50 | FIX_CMAP_BEGIN, | |
0f334a3e | 51 | FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * 2), |
1da177e4 | 52 | #ifdef CONFIG_HIGHMEM |
f8829cae RB |
53 | /* reserved pte's for temporary kernel mappings */ |
54 | FIX_KMAP_BEGIN = FIX_CMAP_END + 1, | |
1da177e4 LT |
55 | FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1, |
56 | #endif | |
57 | __end_of_fixed_addresses | |
58 | }; | |
59 | ||
1da177e4 LT |
60 | /* |
61 | * used by vmalloc.c. | |
62 | * | |
63 | * Leave one empty page between vmalloc'ed areas and | |
64 | * the start of the fixmap, and leave one page empty | |
65 | * at the top of mem.. | |
66 | */ | |
1da177e4 LT |
67 | #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) |
68 | #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) | |
69 | ||
19fd9629 | 70 | #include <asm-generic/fixmap.h> |
1da177e4 | 71 | |
bb86bf28 RB |
72 | #define kmap_get_fixmap_pte(vaddr) \ |
73 | pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr)) | |
74 | ||
84fd089a RB |
75 | /* |
76 | * Called from pgtable_init() | |
77 | */ | |
78 | extern void fixrange_init(unsigned long start, unsigned long end, | |
70342287 | 79 | pgd_t *pgd_base); |
84fd089a RB |
80 | |
81 | ||
1da177e4 | 82 | #endif |