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