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1da177e4 LT |
1 | #ifndef __UM_FIXMAP_H |
2 | #define __UM_FIXMAP_H | |
3 | ||
536788fe | 4 | #include <asm/processor.h> |
1da177e4 LT |
5 | #include <asm/kmap_types.h> |
6 | #include <asm/archparam.h> | |
8192ab42 | 7 | #include <asm/page.h> |
fe1cd987 | 8 | #include <linux/threads.h> |
1da177e4 LT |
9 | |
10 | /* | |
11 | * Here we define all the compile-time 'special' virtual | |
12 | * addresses. The point is to have a constant address at | |
13 | * compile time, but to set the physical address only | |
14 | * in the boot process. We allocate these special addresses | |
15 | * from the end of virtual memory (0xfffff000) backwards. | |
16 | * Also this lets us do fail-safe vmalloc(), we | |
17 | * can guarantee that these special addresses and | |
18 | * vmalloc()-ed addresses never overlap. | |
19 | * | |
20 | * these 'compile-time allocated' memory buffers are | |
21 | * fixed-size 4k pages. (or larger if used with an increment | |
22 | * highger than 1) use fixmap_set(idx,phys) to associate | |
23 | * physical memory with fixmap indices. | |
24 | * | |
25 | * TLB entries of such buffers will not be flushed across | |
26 | * task switches. | |
27 | */ | |
28 | ||
29 | /* | |
30 | * on UP currently we will have no trace of the fixmap mechanizm, | |
31 | * no page table allocations, etc. This might change in the | |
32 | * future, say framebuffers for the console driver(s) could be | |
33 | * fix-mapped? | |
34 | */ | |
35 | enum fixed_addresses { | |
1da177e4 LT |
36 | __end_of_fixed_addresses |
37 | }; | |
38 | ||
39 | extern void __set_fixmap (enum fixed_addresses idx, | |
40 | unsigned long phys, pgprot_t flags); | |
41 | ||
1da177e4 LT |
42 | /* |
43 | * used by vmalloc.c. | |
44 | * | |
45 | * Leave one empty page between vmalloc'ed areas and | |
46 | * the start of the fixmap, and leave one page empty | |
47 | * at the top of mem.. | |
48 | */ | |
1da177e4 | 49 | |
536788fe | 50 | #define FIXADDR_TOP (TASK_SIZE - 2 * PAGE_SIZE) |
1da177e4 LT |
51 | #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) |
52 | #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) | |
53 | ||
a6ce7114 | 54 | #include <asm-generic/fixmap.h> |
1da177e4 LT |
55 | |
56 | #endif |