]>
Commit | Line | Data |
---|---|---|
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 LT |
16 | #include <asm/page.h> |
17 | #ifdef CONFIG_HIGHMEM | |
18 | #include <linux/threads.h> | |
19 | #include <asm/kmap_types.h> | |
20 | #endif | |
21 | ||
22 | /* | |
23 | * Here we define all the compile-time 'special' virtual | |
24 | * addresses. The point is to have a constant address at | |
25 | * compile time, but to set the physical address only | |
26 | * in the boot process. We allocate these special addresses | |
27 | * from the end of virtual memory (0xfffff000) backwards. | |
28 | * Also this lets us do fail-safe vmalloc(), we | |
29 | * can guarantee that these special addresses and | |
30 | * vmalloc()-ed addresses never overlap. | |
31 | * | |
32 | * these 'compile-time allocated' memory buffers are | |
33 | * fixed-size 4k pages. (or larger if used with an increment | |
34 | * highger than 1) use fixmap_set(idx,phys) to associate | |
35 | * physical memory with fixmap indices. | |
36 | * | |
37 | * TLB entries of such buffers will not be flushed across | |
38 | * task switches. | |
39 | */ | |
40 | ||
41 | /* | |
42 | * on UP currently we will have no trace of the fixmap mechanizm, | |
43 | * no page table allocations, etc. This might change in the | |
44 | * future, say framebuffers for the console driver(s) could be | |
45 | * fix-mapped? | |
46 | */ | |
47 | enum fixed_addresses { | |
f8829cae RB |
48 | #define FIX_N_COLOURS 8 |
49 | FIX_CMAP_BEGIN, | |
50 | #ifdef CONFIG_MIPS_MT_SMTC | |
51 | FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS), | |
52 | #else | |
53 | FIX_CMAP_END = FIX_CMAP_BEGIN + FIX_N_COLOURS, | |
54 | #endif | |
1da177e4 | 55 | #ifdef CONFIG_HIGHMEM |
f8829cae RB |
56 | /* reserved pte's for temporary kernel mappings */ |
57 | FIX_KMAP_BEGIN = FIX_CMAP_END + 1, | |
1da177e4 LT |
58 | FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1, |
59 | #endif | |
60 | __end_of_fixed_addresses | |
61 | }; | |
62 | ||
63 | extern void __set_fixmap (enum fixed_addresses idx, | |
64 | unsigned long phys, pgprot_t flags); | |
65 | ||
66 | #define set_fixmap(idx, phys) \ | |
67 | __set_fixmap(idx, phys, PAGE_KERNEL) | |
68 | /* | |
69 | * Some hardware wants to get fixmapped without caching. | |
70 | */ | |
71 | #define set_fixmap_nocache(idx, phys) \ | |
72 | __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE) | |
73 | /* | |
74 | * used by vmalloc.c. | |
75 | * | |
76 | * Leave one empty page between vmalloc'ed areas and | |
77 | * the start of the fixmap, and leave one page empty | |
78 | * at the top of mem.. | |
79 | */ | |
f7a84915 | 80 | #if defined(CONFIG_CPU_TX39XX) || defined(CONFIG_CPU_TX49XX) |
f8829cae | 81 | #define FIXADDR_TOP ((unsigned long)(long)(int)(0xff000000 - 0x20000)) |
f7a84915 | 82 | #else |
f8829cae | 83 | #define FIXADDR_TOP ((unsigned long)(long)(int)0xfffe0000) |
f7a84915 | 84 | #endif |
1da177e4 LT |
85 | #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) |
86 | #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) | |
87 | ||
88 | #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT)) | |
89 | #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT) | |
90 | ||
91 | extern void __this_fixmap_does_not_exist(void); | |
92 | ||
93 | /* | |
94 | * 'index to address' translation. If anyone tries to use the idx | |
95 | * directly without tranlation, we catch the bug with a NULL-deference | |
96 | * kernel oops. Illegal ranges of incoming indices are caught too. | |
97 | */ | |
98 | static inline unsigned long fix_to_virt(const unsigned int idx) | |
99 | { | |
100 | /* | |
101 | * this branch gets completely eliminated after inlining, | |
102 | * except when someone tries to use fixaddr indices in an | |
103 | * illegal way. (such as mixing up address types or using | |
104 | * out-of-range indices). | |
105 | * | |
106 | * If it doesn't get removed, the linker will complain | |
107 | * loudly with a reasonably clear error message.. | |
108 | */ | |
109 | if (idx >= __end_of_fixed_addresses) | |
110 | __this_fixmap_does_not_exist(); | |
111 | ||
112 | return __fix_to_virt(idx); | |
113 | } | |
114 | ||
115 | static inline unsigned long virt_to_fix(const unsigned long vaddr) | |
116 | { | |
117 | BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START); | |
118 | return __virt_to_fix(vaddr); | |
119 | } | |
120 | ||
84fd089a RB |
121 | /* |
122 | * Called from pgtable_init() | |
123 | */ | |
124 | extern void fixrange_init(unsigned long start, unsigned long end, | |
125 | pgd_t *pgd_base); | |
126 | ||
127 | ||
1da177e4 | 128 | #endif |