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
16 #include <linux/config.h>
17 #include <linux/kernel.h>
19 #include <asm/apicdef.h>
22 #include <linux/threads.h>
23 #include <asm/kmap_types.h>
27 * Here we define all the compile-time 'special' virtual
28 * addresses. The point is to have a constant address at
29 * compile time, but to set the physical address only
30 * in the boot process. We allocate these special addresses
31 * from the end of virtual memory (0xfffff000) backwards.
32 * Also this lets us do fail-safe vmalloc(), we
33 * can guarantee that these special addresses and
34 * vmalloc()-ed addresses never overlap.
36 * these 'compile-time allocated' memory buffers are
37 * fixed-size 4k pages. (or larger if used with an increment
38 * highger than 1) use fixmap_set(idx,phys) to associate
39 * physical memory with fixmap indices.
41 * TLB entries of such buffers will not be flushed across
44 enum fixed_addresses {
47 #ifdef CONFIG_X86_LOCAL_APIC
48 FIX_APIC_BASE, /* local (CPU) APIC) -- required for SMP or not */
50 #ifdef CONFIG_X86_IO_APIC
52 FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS-1,
54 #ifdef CONFIG_X86_VISWS_APIC
55 FIX_CO_CPU, /* Cobalt timer */
56 FIX_CO_APIC, /* Cobalt APIC Redirection Table */
57 FIX_LI_PCIA, /* Lithium PCI Bridge A */
58 FIX_LI_PCIB, /* Lithium PCI Bridge B */
60 #ifdef CONFIG_X86_F00F_BUG
61 FIX_F00F_IDT, /* Virtual mapping for IDT */
63 #ifdef CONFIG_X86_CYCLONE_TIMER
64 FIX_CYCLONE_TIMER, /*cyclone timer register*/
67 FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
68 FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
70 #ifdef CONFIG_ACPI_BOOT
72 FIX_ACPI_END = FIX_ACPI_BEGIN + FIX_ACPI_PAGES - 1,
74 #ifdef CONFIG_PCI_MMCONFIG
77 __end_of_permanent_fixed_addresses,
78 /* temporary boot-time mappings, used before ioremap() is functional */
79 #define NR_FIX_BTMAPS 16
80 FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
81 FIX_BTMAP_BEGIN = FIX_BTMAP_END + NR_FIX_BTMAPS - 1,
83 __end_of_fixed_addresses
86 extern void __set_fixmap (enum fixed_addresses idx,
87 unsigned long phys, pgprot_t flags);
89 #define set_fixmap(idx, phys) \
90 __set_fixmap(idx, phys, PAGE_KERNEL)
92 * Some hardware wants to get fixmapped without caching.
94 #define set_fixmap_nocache(idx, phys) \
95 __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
97 #define clear_fixmap(idx) \
98 __set_fixmap(idx, 0, __pgprot(0))
103 * Leave one empty page between vmalloc'ed areas and
104 * the start of the fixmap.
106 #define FIXADDR_TOP (0xfffff000UL)
107 #define __FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
108 #define FIXADDR_START (FIXADDR_TOP - __FIXADDR_SIZE)
110 #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
111 #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
114 * This is the range that is readable by user mode, and things
115 * acting like user mode such as get_user_pages.
117 #define FIXADDR_USER_START (__fix_to_virt(FIX_VSYSCALL))
118 #define FIXADDR_USER_END (FIXADDR_USER_START + PAGE_SIZE)
121 extern void __this_fixmap_does_not_exist(void);
124 * 'index to address' translation. If anyone tries to use the idx
125 * directly without tranlation, we catch the bug with a NULL-deference
126 * kernel oops. Illegal ranges of incoming indices are caught too.
128 static inline unsigned long fix_to_virt(const unsigned int idx)
131 * this branch gets completely eliminated after inlining,
132 * except when someone tries to use fixaddr indices in an
133 * illegal way. (such as mixing up address types or using
134 * out-of-range indices).
136 * If it doesn't get removed, the linker will complain
137 * loudly with a reasonably clear error message..
139 if (idx >= __end_of_fixed_addresses)
140 __this_fixmap_does_not_exist();
142 return __fix_to_virt(idx);
145 static inline unsigned long virt_to_fix(const unsigned long vaddr)
147 BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
148 return __virt_to_fix(vaddr);