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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 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 | |
0f334a3e | 51 | FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS * 2), |
f8829cae | 52 | #else |
0f334a3e | 53 | FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * 2), |
f8829cae | 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 | ||
1da177e4 LT |
63 | /* |
64 | * used by vmalloc.c. | |
65 | * | |
66 | * Leave one empty page between vmalloc'ed areas and | |
67 | * the start of the fixmap, and leave one page empty | |
68 | * at the top of mem.. | |
69 | */ | |
e7300d04 MB |
70 | #ifdef CONFIG_BCM63XX |
71 | #define FIXADDR_TOP ((unsigned long)(long)(int)0xff000000) | |
72 | #else | |
f7a84915 | 73 | #if defined(CONFIG_CPU_TX39XX) || defined(CONFIG_CPU_TX49XX) |
f8829cae | 74 | #define FIXADDR_TOP ((unsigned long)(long)(int)(0xff000000 - 0x20000)) |
f7a84915 | 75 | #else |
f8829cae | 76 | #define FIXADDR_TOP ((unsigned long)(long)(int)0xfffe0000) |
f7a84915 | 77 | #endif |
e7300d04 | 78 | #endif |
1da177e4 LT |
79 | #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) |
80 | #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) | |
81 | ||
82 | #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT)) | |
83 | #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT) | |
84 | ||
85 | extern void __this_fixmap_does_not_exist(void); | |
86 | ||
87 | /* | |
88 | * 'index to address' translation. If anyone tries to use the idx | |
89 | * directly without tranlation, we catch the bug with a NULL-deference | |
90 | * kernel oops. Illegal ranges of incoming indices are caught too. | |
91 | */ | |
92 | static inline unsigned long fix_to_virt(const unsigned int idx) | |
93 | { | |
94 | /* | |
95 | * this branch gets completely eliminated after inlining, | |
96 | * except when someone tries to use fixaddr indices in an | |
97 | * illegal way. (such as mixing up address types or using | |
98 | * out-of-range indices). | |
99 | * | |
100 | * If it doesn't get removed, the linker will complain | |
101 | * loudly with a reasonably clear error message.. | |
102 | */ | |
103 | if (idx >= __end_of_fixed_addresses) | |
104 | __this_fixmap_does_not_exist(); | |
105 | ||
106 | return __fix_to_virt(idx); | |
107 | } | |
108 | ||
109 | static inline unsigned long virt_to_fix(const unsigned long vaddr) | |
110 | { | |
111 | BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START); | |
112 | return __virt_to_fix(vaddr); | |
113 | } | |
114 | ||
bb86bf28 RB |
115 | #define kmap_get_fixmap_pte(vaddr) \ |
116 | pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr)) | |
117 | ||
84fd089a RB |
118 | /* |
119 | * Called from pgtable_init() | |
120 | */ | |
121 | extern void fixrange_init(unsigned long start, unsigned long end, | |
122 | pgd_t *pgd_base); | |
123 | ||
124 | ||
1da177e4 | 125 | #endif |