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 * x86_32 and x86_64 integration by Gustavo F. Padovan, February 2009
12 * Break out common bits to asm-generic by Mark Salter, November 2013
13 */
14
15 #ifndef __ASM_GENERIC_FIXMAP_H
16 #define __ASM_GENERIC_FIXMAP_H
17
18 #include <linux/bug.h>
19 #include <linux/mm_types.h>
20
21 #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
22 #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
23
24 #ifndef __ASSEMBLY__
25 /*
26 * 'index to address' translation. If anyone tries to use the idx
27 * directly without translation, we catch the bug with a NULL-deference
28 * kernel oops. Illegal ranges of incoming indices are caught too.
29 */
30 static __always_inline unsigned long fix_to_virt(const unsigned int idx)
31 {
32 BUILD_BUG_ON(idx >= __end_of_fixed_addresses);
33 return __fix_to_virt(idx);
34 }
35
36 static inline unsigned long virt_to_fix(const unsigned long vaddr)
37 {
38 BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
39 return __virt_to_fix(vaddr);
40 }
41
42 /*
43 * Provide some reasonable defaults for page flags.
44 * Not all architectures use all of these different types and some
45 * architectures use different names.
46 */
47 #ifndef FIXMAP_PAGE_NORMAL
48 #define FIXMAP_PAGE_NORMAL PAGE_KERNEL
49 #endif
50 #if !defined(FIXMAP_PAGE_RO) && defined(PAGE_KERNEL_RO)
51 #define FIXMAP_PAGE_RO PAGE_KERNEL_RO
52 #endif
53 #ifndef FIXMAP_PAGE_NOCACHE
54 #define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE
55 #endif
56 #ifndef FIXMAP_PAGE_IO
57 #define FIXMAP_PAGE_IO PAGE_KERNEL_IO
58 #endif
59 #ifndef FIXMAP_PAGE_CLEAR
60 #define FIXMAP_PAGE_CLEAR __pgprot(0)
61 #endif
62
63 #ifndef set_fixmap
64 #define set_fixmap(idx, phys) \
65 __set_fixmap(idx, phys, FIXMAP_PAGE_NORMAL)
66 #endif
67
68 #ifndef clear_fixmap
69 #define clear_fixmap(idx) \
70 __set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR)
71 #endif
72
73 /* Return a pointer with offset calculated */
74 #define __set_fixmap_offset(idx, phys, flags) \
75 ({ \
76 unsigned long ________addr; \
77 __set_fixmap(idx, phys, flags); \
78 ________addr = fix_to_virt(idx) + ((phys) & (PAGE_SIZE - 1)); \
79 ________addr; \
80 })
81
82 #define set_fixmap_offset(idx, phys) \
83 __set_fixmap_offset(idx, phys, FIXMAP_PAGE_NORMAL)
84
85 /*
86 * Some hardware wants to get fixmapped without caching.
87 */
88 #define set_fixmap_nocache(idx, phys) \
89 __set_fixmap(idx, phys, FIXMAP_PAGE_NOCACHE)
90
91 #define set_fixmap_offset_nocache(idx, phys) \
92 __set_fixmap_offset(idx, phys, FIXMAP_PAGE_NOCACHE)
93
94 /*
95 * Some fixmaps are for IO
96 */
97 #define set_fixmap_io(idx, phys) \
98 __set_fixmap(idx, phys, FIXMAP_PAGE_IO)
99
100 #endif /* __ASSEMBLY__ */
101 #endif /* __ASM_GENERIC_FIXMAP_H */
102
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