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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | #ifndef __UM_FIXMAP_H |
3 | #define __UM_FIXMAP_H | |
4 | ||
536788fe | 5 | #include <asm/processor.h> |
1da177e4 LT |
6 | #include <asm/kmap_types.h> |
7 | #include <asm/archparam.h> | |
8192ab42 | 8 | #include <asm/page.h> |
fe1cd987 | 9 | #include <linux/threads.h> |
1da177e4 LT |
10 | |
11 | /* | |
12 | * Here we define all the compile-time 'special' virtual | |
13 | * addresses. The point is to have a constant address at | |
14 | * compile time, but to set the physical address only | |
15 | * in the boot process. We allocate these special addresses | |
16 | * from the end of virtual memory (0xfffff000) backwards. | |
17 | * Also this lets us do fail-safe vmalloc(), we | |
18 | * can guarantee that these special addresses and | |
19 | * vmalloc()-ed addresses never overlap. | |
20 | * | |
21 | * these 'compile-time allocated' memory buffers are | |
22 | * fixed-size 4k pages. (or larger if used with an increment | |
23 | * highger than 1) use fixmap_set(idx,phys) to associate | |
24 | * physical memory with fixmap indices. | |
25 | * | |
26 | * TLB entries of such buffers will not be flushed across | |
27 | * task switches. | |
28 | */ | |
29 | ||
30 | /* | |
31 | * on UP currently we will have no trace of the fixmap mechanizm, | |
32 | * no page table allocations, etc. This might change in the | |
33 | * future, say framebuffers for the console driver(s) could be | |
34 | * fix-mapped? | |
35 | */ | |
36 | enum fixed_addresses { | |
1da177e4 LT |
37 | __end_of_fixed_addresses |
38 | }; | |
39 | ||
40 | extern void __set_fixmap (enum fixed_addresses idx, | |
41 | unsigned long phys, pgprot_t flags); | |
42 | ||
1da177e4 LT |
43 | /* |
44 | * used by vmalloc.c. | |
45 | * | |
46 | * Leave one empty page between vmalloc'ed areas and | |
47 | * the start of the fixmap, and leave one page empty | |
48 | * at the top of mem.. | |
49 | */ | |
1da177e4 | 50 | |
536788fe | 51 | #define FIXADDR_TOP (TASK_SIZE - 2 * PAGE_SIZE) |
1da177e4 LT |
52 | #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) |
53 | #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) | |
54 | ||
a6ce7114 | 55 | #include <asm-generic/fixmap.h> |
1da177e4 LT |
56 | |
57 | #endif |