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
20 #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
21 #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
22
23 #ifndef __ASSEMBLY__
24 /*
25 * 'index to address' translation. If anyone tries to use the idx
26 * directly without translation, we catch the bug with a NULL-deference
27 * kernel oops. Illegal ranges of incoming indices are caught too.
28 */
fix_to_virt(const unsigned int idx)29 static __always_inline unsigned long fix_to_virt(const unsigned int idx)
30 {
31 BUILD_BUG_ON(idx >= __end_of_fixed_addresses);
32 return __fix_to_virt(idx);
33 }
34
virt_to_fix(const unsigned long vaddr)35 static inline unsigned long virt_to_fix(const unsigned long vaddr)
36 {
37 BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
38 return __virt_to_fix(vaddr);
39 }
40
41 /*
42 * Provide some reasonable defaults for page flags.
43 * Not all architectures use all of these different types and some
44 * architectures use different names.
45 */
46 #ifndef FIXMAP_PAGE_NORMAL
47 #define FIXMAP_PAGE_NORMAL PAGE_KERNEL
48 #endif
49 #if !defined(FIXMAP_PAGE_RO) && defined(PAGE_KERNEL_RO)
50 #define FIXMAP_PAGE_RO PAGE_KERNEL_RO
51 #endif
52 #ifndef FIXMAP_PAGE_NOCACHE
53 #define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE
54 #endif
55 #ifndef FIXMAP_PAGE_IO
56 #define FIXMAP_PAGE_IO PAGE_KERNEL_IO
57 #endif
58 #ifndef FIXMAP_PAGE_CLEAR
59 #define FIXMAP_PAGE_CLEAR __pgprot(0)
60 #endif
61
62 #ifndef set_fixmap
63 #define set_fixmap(idx, phys) \
64 __set_fixmap(idx, phys, FIXMAP_PAGE_NORMAL)
65 #endif
66
67 #ifndef clear_fixmap
68 #define clear_fixmap(idx) \
69 __set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR)
70 #endif
71
72 /* Return a pointer with offset calculated */
73 #define __set_fixmap_offset(idx, phys, flags) \
74 ({ \
75 unsigned long ________addr; \
76 __set_fixmap(idx, phys, flags); \
77 ________addr = fix_to_virt(idx) + ((phys) & (PAGE_SIZE - 1)); \
78 ________addr; \
79 })
80
81 #define set_fixmap_offset(idx, phys) \
82 __set_fixmap_offset(idx, phys, FIXMAP_PAGE_NORMAL)
83
84 /*
85 * Some hardware wants to get fixmapped without caching.
86 */
87 #define set_fixmap_nocache(idx, phys) \
88 __set_fixmap(idx, phys, FIXMAP_PAGE_NOCACHE)
89
90 #define set_fixmap_offset_nocache(idx, phys) \
91 __set_fixmap_offset(idx, phys, FIXMAP_PAGE_NOCACHE)
92
93 /*
94 * Some fixmaps are for IO
95 */
96 #define set_fixmap_io(idx, phys) \
97 __set_fixmap(idx, phys, FIXMAP_PAGE_IO)
98
99 #define set_fixmap_offset_io(idx, phys) \
100 __set_fixmap_offset(idx, phys, FIXMAP_PAGE_IO)
101
102 #endif /* __ASSEMBLY__ */
103 #endif /* __ASM_GENERIC_FIXMAP_H */
104