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 */
30static __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
36static 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