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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 */
12
13#ifndef _ASM_FIXMAP_H
14#define _ASM_FIXMAP_H
15
16#include <linux/kernel.h>
17#include <linux/threads.h>
18#include <asm/page.h>
19#ifdef CONFIG_HIGHMEM
20#include <asm/kmap_types.h>
21#endif
22
23/*
24 * Here we define all the compile-time 'special' virtual
25 * addresses. The point is to have a constant address at
26 * compile time, but to set the physical address only
27 * in the boot process. We allocate these special addresses
28 * from the end of P3 backwards.
29 * Also this lets us do fail-safe vmalloc(), we
30 * can guarantee that these special addresses and
31 * vmalloc()-ed addresses never overlap.
32 *
33 * these 'compile-time allocated' memory buffers are
34 * fixed-size 4k pages. (or larger if used with an increment
35 * highger than 1) use fixmap_set(idx,phys) to associate
36 * physical memory with fixmap indices.
37 *
38 * TLB entries of such buffers will not be flushed across
39 * task switches.
40 */
41
42/*
43 * on UP currently we will have no trace of the fixmap mechanizm,
44 * no page table allocations, etc. This might change in the
45 * future, say framebuffers for the console driver(s) could be
46 * fix-mapped?
47 */
48enum fixed_addresses {
49 /*
50 * The FIX_CMAP entries are used by kmap_coherent() to get virtual
51 * addresses which are of a known color, and so their values are
52 * important. __fix_to_virt(FIX_CMAP_END - n) must give an address
53 * which is the same color as a page (n<<PAGE_SHIFT).
54 */
55#define FIX_N_COLOURS 8
56 FIX_CMAP_BEGIN,
57 FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS) - 1,
58
59#ifdef CONFIG_HIGHMEM
60 FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
61 FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1,
62#endif
63
64#ifdef CONFIG_IOREMAP_FIXED
65 /*
66 * FIX_IOREMAP entries are useful for mapping physical address
67 * space before ioremap() is useable, e.g. really early in boot
68 * before kmalloc() is working.
69 */
70#define FIX_N_IOREMAPS 32
71 FIX_IOREMAP_BEGIN,
72 FIX_IOREMAP_END = FIX_IOREMAP_BEGIN + FIX_N_IOREMAPS - 1,
73#endif
74
75 __end_of_fixed_addresses
76};
77
78extern void __set_fixmap(enum fixed_addresses idx,
79 unsigned long phys, pgprot_t flags);
80extern void __clear_fixmap(enum fixed_addresses idx, pgprot_t flags);
81
82#define set_fixmap(idx, phys) \
83 __set_fixmap(idx, phys, PAGE_KERNEL)
84/*
85 * Some hardware wants to get fixmapped without caching.
86 */
87#define set_fixmap_nocache(idx, phys) \
88 __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
89/*
90 * used by vmalloc.c.
91 *
92 * Leave one empty page between vmalloc'ed areas and
93 * the start of the fixmap, and leave one page empty
94 * at the top of mem..
95 */
96#ifdef CONFIG_SUPERH32
97#define FIXADDR_TOP (P4SEG - PAGE_SIZE)
98#else
99#define FIXADDR_TOP ((unsigned long)(-PAGE_SIZE))
100#endif
101#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
102#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
103
104#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
105#define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
106
107extern void __this_fixmap_does_not_exist(void);
108
109/*
110 * 'index to address' translation. If anyone tries to use the idx
111 * directly without tranlation, we catch the bug with a NULL-deference
112 * kernel oops. Illegal ranges of incoming indices are caught too.
113 */
114static inline unsigned long fix_to_virt(const unsigned int idx)
115{
116 /*
117 * this branch gets completely eliminated after inlining,
118 * except when someone tries to use fixaddr indices in an
119 * illegal way. (such as mixing up address types or using
120 * out-of-range indices).
121 *
122 * If it doesn't get removed, the linker will complain
123 * loudly with a reasonably clear error message..
124 */
125 if (idx >= __end_of_fixed_addresses)
126 __this_fixmap_does_not_exist();
127
128 return __fix_to_virt(idx);
129}
130
131static inline unsigned long virt_to_fix(const unsigned long vaddr)
132{
133 BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
134 return __virt_to_fix(vaddr);
135}
136#endif
1/* SPDX-License-Identifier: GPL-2.0
2 *
3 * fixmap.h: compile-time virtual memory allocation
4 *
5 * Copyright (C) 1998 Ingo Molnar
6 *
7 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
8 */
9
10#ifndef _ASM_FIXMAP_H
11#define _ASM_FIXMAP_H
12
13#include <linux/kernel.h>
14#include <linux/threads.h>
15#include <asm/page.h>
16#ifdef CONFIG_HIGHMEM
17#include <asm/kmap_types.h>
18#endif
19
20/*
21 * Here we define all the compile-time 'special' virtual
22 * addresses. The point is to have a constant address at
23 * compile time, but to set the physical address only
24 * in the boot process. We allocate these special addresses
25 * from the end of P3 backwards.
26 * Also this lets us do fail-safe vmalloc(), we
27 * can guarantee that these special addresses and
28 * vmalloc()-ed addresses never overlap.
29 *
30 * these 'compile-time allocated' memory buffers are
31 * fixed-size 4k pages. (or larger if used with an increment
32 * highger than 1) use fixmap_set(idx,phys) to associate
33 * physical memory with fixmap indices.
34 *
35 * TLB entries of such buffers will not be flushed across
36 * task switches.
37 */
38
39/*
40 * on UP currently we will have no trace of the fixmap mechanizm,
41 * no page table allocations, etc. This might change in the
42 * future, say framebuffers for the console driver(s) could be
43 * fix-mapped?
44 */
45enum fixed_addresses {
46 /*
47 * The FIX_CMAP entries are used by kmap_coherent() to get virtual
48 * addresses which are of a known color, and so their values are
49 * important. __fix_to_virt(FIX_CMAP_END - n) must give an address
50 * which is the same color as a page (n<<PAGE_SHIFT).
51 */
52#define FIX_N_COLOURS 8
53 FIX_CMAP_BEGIN,
54 FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS) - 1,
55
56#ifdef CONFIG_HIGHMEM
57 FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
58 FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1,
59#endif
60
61#ifdef CONFIG_IOREMAP_FIXED
62 /*
63 * FIX_IOREMAP entries are useful for mapping physical address
64 * space before ioremap() is useable, e.g. really early in boot
65 * before kmalloc() is working.
66 */
67#define FIX_N_IOREMAPS 32
68 FIX_IOREMAP_BEGIN,
69 FIX_IOREMAP_END = FIX_IOREMAP_BEGIN + FIX_N_IOREMAPS - 1,
70#endif
71
72 __end_of_fixed_addresses
73};
74
75extern void __set_fixmap(enum fixed_addresses idx,
76 unsigned long phys, pgprot_t flags);
77extern void __clear_fixmap(enum fixed_addresses idx, pgprot_t flags);
78
79/*
80 * used by vmalloc.c.
81 *
82 * Leave one empty page between vmalloc'ed areas and
83 * the start of the fixmap, and leave one page empty
84 * at the top of mem..
85 */
86#ifdef CONFIG_SUPERH32
87#define FIXADDR_TOP (P4SEG - PAGE_SIZE)
88#else
89#define FIXADDR_TOP ((unsigned long)(-PAGE_SIZE))
90#endif
91#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
92#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
93
94#define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE
95
96#include <asm-generic/fixmap.h>
97
98#endif