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 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)
27 #include <linux/kernel.h>
29 #include <asm/apicdef.h>
32 #include <linux/threads.h>
33 #include <asm/kmap_types.h>
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.
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.
51 * TLB entries of such buffers will not be flushed across
54 enum fixed_addresses
{
58 FIX_EARLYCON_MEM_BASE
,
59 #ifdef CONFIG_X86_LOCAL_APIC
60 FIX_APIC_BASE
, /* local (CPU) APIC) -- required for SMP or not */
62 #ifdef CONFIG_X86_IO_APIC
64 FIX_IO_APIC_BASE_END
= FIX_IO_APIC_BASE_0
+ MAX_IO_APICS
-1,
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 */
72 #ifdef CONFIG_X86_F00F_BUG
73 FIX_F00F_IDT
, /* Virtual mapping for IDT */
75 #ifdef CONFIG_X86_CYCLONE_TIMER
76 FIX_CYCLONE_TIMER
, /*cyclone timer register*/
79 FIX_KMAP_BEGIN
, /* reserved pte's for temporary kernel mappings */
80 FIX_KMAP_END
= FIX_KMAP_BEGIN
+(KM_TYPE_NR
*NR_CPUS
)-1,
84 FIX_ACPI_END
= FIX_ACPI_BEGIN
+ FIX_ACPI_PAGES
- 1,
86 #ifdef CONFIG_PCI_MMCONFIG
89 #ifdef CONFIG_PARAVIRT
92 __end_of_permanent_fixed_addresses
,
94 * 256 temporary boot-time mappings, used by early_ioremap(),
95 * before ioremap() is functional.
97 * We round it up to the next 512 pages boundary so that we
98 * can have a single pgd entry and a single pte table:
100 #define NR_FIX_BTMAPS 64
101 #define FIX_BTMAPS_NESTING 4
103 __end_of_permanent_fixed_addresses
+ 512 -
104 (__end_of_permanent_fixed_addresses
& 511),
105 FIX_BTMAP_BEGIN
= FIX_BTMAP_END
+ NR_FIX_BTMAPS
*FIX_BTMAPS_NESTING
- 1,
107 #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
110 __end_of_fixed_addresses
113 extern void __set_fixmap (enum fixed_addresses idx
,
114 unsigned long phys
, pgprot_t flags
);
115 extern void reserve_top_address(unsigned long reserve
);
117 #define set_fixmap(idx, phys) \
118 __set_fixmap(idx, phys, PAGE_KERNEL)
120 * Some hardware wants to get fixmapped without caching.
122 #define set_fixmap_nocache(idx, phys) \
123 __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
125 #define clear_fixmap(idx) \
126 __set_fixmap(idx, 0, __pgprot(0))
128 #define FIXADDR_TOP ((unsigned long)__FIXADDR_TOP)
130 #define __FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
131 #define __FIXADDR_BOOT_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
132 #define FIXADDR_START (FIXADDR_TOP - __FIXADDR_SIZE)
133 #define FIXADDR_BOOT_START (FIXADDR_TOP - __FIXADDR_BOOT_SIZE)
135 #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
136 #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
138 extern void __this_fixmap_does_not_exist(void);
141 * 'index to address' translation. If anyone tries to use the idx
142 * directly without tranlation, we catch the bug with a NULL-deference
143 * kernel oops. Illegal ranges of incoming indices are caught too.
145 static __always_inline
unsigned long fix_to_virt(const unsigned int idx
)
148 * this branch gets completely eliminated after inlining,
149 * except when someone tries to use fixaddr indices in an
150 * illegal way. (such as mixing up address types or using
151 * out-of-range indices).
153 * If it doesn't get removed, the linker will complain
154 * loudly with a reasonably clear error message..
156 if (idx
>= __end_of_fixed_addresses
)
157 __this_fixmap_does_not_exist();
159 return __fix_to_virt(idx
);
162 static inline unsigned long virt_to_fix(const unsigned long vaddr
)
164 BUG_ON(vaddr
>= FIXADDR_TOP
|| vaddr
< FIXADDR_START
);
165 return __virt_to_fix(vaddr
);
168 #endif /* !__ASSEMBLY__ */