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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
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/config.h>
17
18/* used by vmalloc.c, vsyscall.lds.S.
19 *
20 * Leave one empty page between vmalloc'ed areas and
21 * the start of the fixmap.
22 */
23#define __FIXADDR_TOP 0xfffff000
24
25#ifndef __ASSEMBLY__
26#include <linux/kernel.h>
27#include <asm/acpi.h>
28#include <asm/apicdef.h>
29#include <asm/page.h>
30#ifdef CONFIG_HIGHMEM
31#include <linux/threads.h>
32#include <asm/kmap_types.h>
33#endif
34
35/*
36 * Here we define all the compile-time 'special' virtual
37 * addresses. The point is to have a constant address at
38 * compile time, but to set the physical address only
39 * in the boot process. We allocate these special addresses
40 * from the end of virtual memory (0xfffff000) backwards.
41 * Also this lets us do fail-safe vmalloc(), we
42 * can guarantee that these special addresses and
43 * vmalloc()-ed addresses never overlap.
44 *
45 * these 'compile-time allocated' memory buffers are
46 * fixed-size 4k pages. (or larger if used with an increment
47 * highger than 1) use fixmap_set(idx,phys) to associate
48 * physical memory with fixmap indices.
49 *
50 * TLB entries of such buffers will not be flushed across
51 * task switches.
52 */
53enum fixed_addresses {
54 FIX_HOLE,
55 FIX_VSYSCALL,
56#ifdef CONFIG_X86_LOCAL_APIC
57 FIX_APIC_BASE, /* local (CPU) APIC) -- required for SMP or not */
58#endif
59#ifdef CONFIG_X86_IO_APIC
60 FIX_IO_APIC_BASE_0,
61 FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS-1,
62#endif
63#ifdef CONFIG_X86_VISWS_APIC
64 FIX_CO_CPU, /* Cobalt timer */
65 FIX_CO_APIC, /* Cobalt APIC Redirection Table */
66 FIX_LI_PCIA, /* Lithium PCI Bridge A */
67 FIX_LI_PCIB, /* Lithium PCI Bridge B */
68#endif
69#ifdef CONFIG_X86_F00F_BUG
70 FIX_F00F_IDT, /* Virtual mapping for IDT */
71#endif
72#ifdef CONFIG_X86_CYCLONE_TIMER
73 FIX_CYCLONE_TIMER, /*cyclone timer register*/
74#endif
75#ifdef CONFIG_HIGHMEM
76 FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
77 FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
78#endif
79#ifdef CONFIG_ACPI
80 FIX_ACPI_BEGIN,
81 FIX_ACPI_END = FIX_ACPI_BEGIN + FIX_ACPI_PAGES - 1,
82#endif
83#ifdef CONFIG_PCI_MMCONFIG
84 FIX_PCIE_MCFG,
85#endif
86 __end_of_permanent_fixed_addresses,
87 /* temporary boot-time mappings, used before ioremap() is functional */
88#define NR_FIX_BTMAPS 16
89 FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
90 FIX_BTMAP_BEGIN = FIX_BTMAP_END + NR_FIX_BTMAPS - 1,
91 FIX_WP_TEST,
92 __end_of_fixed_addresses
93};
94
95extern void __set_fixmap (enum fixed_addresses idx,
96 unsigned long phys, pgprot_t flags);
97
98#define set_fixmap(idx, phys) \
99 __set_fixmap(idx, phys, PAGE_KERNEL)
100/*
101 * Some hardware wants to get fixmapped without caching.
102 */
103#define set_fixmap_nocache(idx, phys) \
104 __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
105
106#define clear_fixmap(idx) \
107 __set_fixmap(idx, 0, __pgprot(0))
108
109#define FIXADDR_TOP ((unsigned long)__FIXADDR_TOP)
110
111#define __FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
112#define __FIXADDR_BOOT_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
113#define FIXADDR_START (FIXADDR_TOP - __FIXADDR_SIZE)
114#define FIXADDR_BOOT_START (FIXADDR_TOP - __FIXADDR_BOOT_SIZE)
115
116#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
117#define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
118
119/*
120 * This is the range that is readable by user mode, and things
121 * acting like user mode such as get_user_pages.
122 */
123#define FIXADDR_USER_START (__fix_to_virt(FIX_VSYSCALL))
124#define FIXADDR_USER_END (FIXADDR_USER_START + PAGE_SIZE)
125
126
127extern void __this_fixmap_does_not_exist(void);
128
129/*
130 * 'index to address' translation. If anyone tries to use the idx
131 * directly without tranlation, we catch the bug with a NULL-deference
132 * kernel oops. Illegal ranges of incoming indices are caught too.
133 */
134static __always_inline unsigned long fix_to_virt(const unsigned int idx)
135{
136 /*
137 * this branch gets completely eliminated after inlining,
138 * except when someone tries to use fixaddr indices in an
139 * illegal way. (such as mixing up address types or using
140 * out-of-range indices).
141 *
142 * If it doesn't get removed, the linker will complain
143 * loudly with a reasonably clear error message..
144 */
145 if (idx >= __end_of_fixed_addresses)
146 __this_fixmap_does_not_exist();
147
148 return __fix_to_virt(idx);
149}
150
151static inline unsigned long virt_to_fix(const unsigned long vaddr)
152{
153 BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
154 return __virt_to_fix(vaddr);
155}
156
157#endif /* !__ASSEMBLY__ */
158#endif