2 * fixmap.h: compile-time virtual memory allocation
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
8 * Copyright (C) 1998 Ingo Molnar
10 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
17 /* used by vmalloc.c, vsyscall.lds.S.
19 * Leave one empty page between vmalloc'ed areas and
20 * the start of the fixmap.
22 #define __FIXADDR_TOP 0xfffff000
25 #include <linux/kernel.h>
27 #include <asm/apicdef.h>
30 #include <linux/threads.h>
31 #include <asm/kmap_types.h>
35 * Here we define all the compile-time 'special' virtual
36 * addresses. The point is to have a constant address at
37 * compile time, but to set the physical address only
38 * in the boot process. We allocate these special addresses
39 * from the end of virtual memory (0xfffff000) backwards.
40 * Also this lets us do fail-safe vmalloc(), we
41 * can guarantee that these special addresses and
42 * vmalloc()-ed addresses never overlap.
44 * these 'compile-time allocated' memory buffers are
45 * fixed-size 4k pages. (or larger if used with an increment
46 * highger than 1) use fixmap_set(idx,phys) to associate
47 * physical memory with fixmap indices.
49 * TLB entries of such buffers will not be flushed across
52 enum fixed_addresses
{
55 #ifdef CONFIG_X86_LOCAL_APIC
56 FIX_APIC_BASE
, /* local (CPU) APIC) -- required for SMP or not */
58 #ifdef CONFIG_X86_IO_APIC
60 FIX_IO_APIC_BASE_END
= FIX_IO_APIC_BASE_0
+ MAX_IO_APICS
-1,
62 #ifdef CONFIG_X86_VISWS_APIC
63 FIX_CO_CPU
, /* Cobalt timer */
64 FIX_CO_APIC
, /* Cobalt APIC Redirection Table */
65 FIX_LI_PCIA
, /* Lithium PCI Bridge A */
66 FIX_LI_PCIB
, /* Lithium PCI Bridge B */
68 #ifdef CONFIG_X86_F00F_BUG
69 FIX_F00F_IDT
, /* Virtual mapping for IDT */
71 #ifdef CONFIG_X86_CYCLONE_TIMER
72 FIX_CYCLONE_TIMER
, /*cyclone timer register*/
75 FIX_KMAP_BEGIN
, /* reserved pte's for temporary kernel mappings */
76 FIX_KMAP_END
= FIX_KMAP_BEGIN
+(KM_TYPE_NR
*NR_CPUS
)-1,
80 FIX_ACPI_END
= FIX_ACPI_BEGIN
+ FIX_ACPI_PAGES
- 1,
82 #ifdef CONFIG_PCI_MMCONFIG
85 __end_of_permanent_fixed_addresses
,
86 /* temporary boot-time mappings, used before ioremap() is functional */
87 #define NR_FIX_BTMAPS 16
88 FIX_BTMAP_END
= __end_of_permanent_fixed_addresses
,
89 FIX_BTMAP_BEGIN
= FIX_BTMAP_END
+ NR_FIX_BTMAPS
- 1,
91 __end_of_fixed_addresses
94 extern void __set_fixmap (enum fixed_addresses idx
,
95 unsigned long phys
, pgprot_t flags
);
97 #define set_fixmap(idx, phys) \
98 __set_fixmap(idx, phys, PAGE_KERNEL)
100 * Some hardware wants to get fixmapped without caching.
102 #define set_fixmap_nocache(idx, phys) \
103 __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
105 #define clear_fixmap(idx) \
106 __set_fixmap(idx, 0, __pgprot(0))
108 #define FIXADDR_TOP ((unsigned long)__FIXADDR_TOP)
110 #define __FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
111 #define __FIXADDR_BOOT_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
112 #define FIXADDR_START (FIXADDR_TOP - __FIXADDR_SIZE)
113 #define FIXADDR_BOOT_START (FIXADDR_TOP - __FIXADDR_BOOT_SIZE)
115 #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
116 #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
118 extern void __this_fixmap_does_not_exist(void);
121 * 'index to address' translation. If anyone tries to use the idx
122 * directly without tranlation, we catch the bug with a NULL-deference
123 * kernel oops. Illegal ranges of incoming indices are caught too.
125 static __always_inline
unsigned long fix_to_virt(const unsigned int idx
)
128 * this branch gets completely eliminated after inlining,
129 * except when someone tries to use fixaddr indices in an
130 * illegal way. (such as mixing up address types or using
131 * out-of-range indices).
133 * If it doesn't get removed, the linker will complain
134 * loudly with a reasonably clear error message..
136 if (idx
>= __end_of_fixed_addresses
)
137 __this_fixmap_does_not_exist();
139 return __fix_to_virt(idx
);
142 static inline unsigned long virt_to_fix(const unsigned long vaddr
)
144 BUG_ON(vaddr
>= FIXADDR_TOP
|| vaddr
< FIXADDR_START
);
145 return __virt_to_fix(vaddr
);
148 #endif /* !__ASSEMBLY__ */