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 */
29static __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
35static 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#ifndef FIXMAP_PAGE_NOCACHE
50#define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE
51#endif
52#ifndef FIXMAP_PAGE_IO
53#define FIXMAP_PAGE_IO PAGE_KERNEL_IO
54#endif
55#ifndef FIXMAP_PAGE_CLEAR
56#define FIXMAP_PAGE_CLEAR __pgprot(0)
57#endif
58
59#ifndef set_fixmap
60#define set_fixmap(idx, phys)				\
61	__set_fixmap(idx, phys, FIXMAP_PAGE_NORMAL)
62#endif
63
64#ifndef clear_fixmap
65#define clear_fixmap(idx)			\
66	__set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR)
67#endif
68
69/* Return a pointer with offset calculated */
70#define __set_fixmap_offset(idx, phys, flags)		      \
71({							      \
72	unsigned long addr;				      \
73	__set_fixmap(idx, phys, flags);			      \
74	addr = fix_to_virt(idx) + ((phys) & (PAGE_SIZE - 1)); \
75	addr;						      \
76})
77
78#define set_fixmap_offset(idx, phys) \
79	__set_fixmap_offset(idx, phys, FIXMAP_PAGE_NORMAL)
80
81/*
82 * Some hardware wants to get fixmapped without caching.
83 */
84#define set_fixmap_nocache(idx, phys) \
85	__set_fixmap(idx, phys, FIXMAP_PAGE_NOCACHE)
86
87#define set_fixmap_offset_nocache(idx, phys) \
88	__set_fixmap_offset(idx, phys, FIXMAP_PAGE_NOCACHE)
89
90/*
91 * Some fixmaps are for IO
92 */
93#define set_fixmap_io(idx, phys) \
94	__set_fixmap(idx, phys, FIXMAP_PAGE_IO)
95
96#define set_fixmap_offset_io(idx, phys) \
97	__set_fixmap_offset(idx, phys, FIXMAP_PAGE_IO)
98
99#endif /* __ASSEMBLY__ */
100#endif /* __ASM_GENERIC_FIXMAP_H */
101