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2c419bde KG |
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 | * Copyright 2008 Freescale Semiconductor Inc. | |
11 | * Port to powerpc added by Kumar Gala | |
12 | */ | |
13 | ||
14 | #ifndef _ASM_FIXMAP_H | |
15 | #define _ASM_FIXMAP_H | |
16 | ||
2c419bde KG |
17 | #ifndef __ASSEMBLY__ |
18 | #include <linux/kernel.h> | |
19 | #include <asm/page.h> | |
20 | #ifdef CONFIG_HIGHMEM | |
21 | #include <linux/threads.h> | |
22 | #include <asm/kmap_types.h> | |
23 | #endif | |
24 | ||
f637a49e BH |
25 | #define FIXADDR_TOP ((unsigned long)(-PAGE_SIZE)) |
26 | ||
2c419bde KG |
27 | /* |
28 | * Here we define all the compile-time 'special' virtual | |
29 | * addresses. The point is to have a constant address at | |
30 | * compile time, but to set the physical address only | |
31 | * in the boot process. We allocate these special addresses | |
32 | * from the end of virtual memory (0xfffff000) backwards. | |
33 | * Also this lets us do fail-safe vmalloc(), we | |
34 | * can guarantee that these special addresses and | |
35 | * vmalloc()-ed addresses never overlap. | |
36 | * | |
37 | * these 'compile-time allocated' memory buffers are | |
38 | * fixed-size 4k pages. (or larger if used with an increment | |
39 | * highger than 1) use fixmap_set(idx,phys) to associate | |
40 | * physical memory with fixmap indices. | |
41 | * | |
42 | * TLB entries of such buffers will not be flushed across | |
43 | * task switches. | |
44 | */ | |
45 | enum fixed_addresses { | |
46 | FIX_HOLE, | |
b8e8efaa AH |
47 | /* reserve the top 128K for early debugging purposes */ |
48 | FIX_EARLY_DEBUG_TOP = FIX_HOLE, | |
49 | FIX_EARLY_DEBUG_BASE = FIX_EARLY_DEBUG_TOP+((128*1024)/PAGE_SIZE)-1, | |
2c419bde KG |
50 | #ifdef CONFIG_HIGHMEM |
51 | FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */ | |
52 | FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1, | |
53 | #endif | |
54 | /* FIX_PCIE_MCFG, */ | |
55 | __end_of_fixed_addresses | |
56 | }; | |
57 | ||
58 | extern void __set_fixmap (enum fixed_addresses idx, | |
59 | phys_addr_t phys, pgprot_t flags); | |
60 | ||
61 | #define set_fixmap(idx, phys) \ | |
62 | __set_fixmap(idx, phys, PAGE_KERNEL) | |
63 | /* | |
64 | * Some hardware wants to get fixmapped without caching. | |
65 | */ | |
66 | #define set_fixmap_nocache(idx, phys) \ | |
8d1cf34e | 67 | __set_fixmap(idx, phys, PAGE_KERNEL_NCG) |
2c419bde KG |
68 | |
69 | #define clear_fixmap(idx) \ | |
70 | __set_fixmap(idx, 0, __pgprot(0)) | |
71 | ||
72 | #define __FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) | |
73 | #define FIXADDR_START (FIXADDR_TOP - __FIXADDR_SIZE) | |
74 | ||
75 | #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT)) | |
76 | #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT) | |
77 | ||
78 | extern void __this_fixmap_does_not_exist(void); | |
79 | ||
80 | /* | |
81 | * 'index to address' translation. If anyone tries to use the idx | |
82 | * directly without tranlation, we catch the bug with a NULL-deference | |
83 | * kernel oops. Illegal ranges of incoming indices are caught too. | |
84 | */ | |
85 | static __always_inline unsigned long fix_to_virt(const unsigned int idx) | |
86 | { | |
87 | /* | |
88 | * this branch gets completely eliminated after inlining, | |
89 | * except when someone tries to use fixaddr indices in an | |
90 | * illegal way. (such as mixing up address types or using | |
91 | * out-of-range indices). | |
92 | * | |
93 | * If it doesn't get removed, the linker will complain | |
94 | * loudly with a reasonably clear error message.. | |
95 | */ | |
96 | if (idx >= __end_of_fixed_addresses) | |
97 | __this_fixmap_does_not_exist(); | |
98 | ||
99 | return __fix_to_virt(idx); | |
100 | } | |
101 | ||
102 | static inline unsigned long virt_to_fix(const unsigned long vaddr) | |
103 | { | |
104 | BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START); | |
105 | return __virt_to_fix(vaddr); | |
106 | } | |
107 | ||
108 | #endif /* !__ASSEMBLY__ */ | |
109 | #endif |