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.
23 #define __FIXADDR_TOP 0xfffff000
26 #include <linux/kernel.h>
28 #include <asm/apicdef.h>
31 #include <linux/threads.h>
32 #include <asm/kmap_types.h>
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.
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.
50 * TLB entries of such buffers will not be flushed across
53 enum fixed_addresses {
56 #ifdef CONFIG_X86_LOCAL_APIC
57 FIX_APIC_BASE, /* local (CPU) APIC) -- required for SMP or not */
59 #ifdef CONFIG_X86_IO_APIC
61 FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS-1,
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 */
69 #ifdef CONFIG_X86_F00F_BUG
70 FIX_F00F_IDT, /* Virtual mapping for IDT */
72 #ifdef CONFIG_X86_CYCLONE_TIMER
73 FIX_CYCLONE_TIMER, /*cyclone timer register*/
76 FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
77 FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
81 FIX_ACPI_END = FIX_ACPI_BEGIN + FIX_ACPI_PAGES - 1,
83 #ifdef CONFIG_PCI_MMCONFIG
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,
92 __end_of_fixed_addresses
95 extern void __set_fixmap (enum fixed_addresses idx,
96 unsigned long phys, pgprot_t flags);
98 #define set_fixmap(idx, phys) \
99 __set_fixmap(idx, phys, PAGE_KERNEL)
101 * Some hardware wants to get fixmapped without caching.
103 #define set_fixmap_nocache(idx, phys) \
104 __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
106 #define clear_fixmap(idx) \
107 __set_fixmap(idx, 0, __pgprot(0))
109 #define FIXADDR_TOP ((unsigned long)__FIXADDR_TOP)
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)
116 #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
117 #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
119 extern void __this_fixmap_does_not_exist(void);
122 * 'index to address' translation. If anyone tries to use the idx
123 * directly without tranlation, we catch the bug with a NULL-deference
124 * kernel oops. Illegal ranges of incoming indices are caught too.
126 static __always_inline unsigned long fix_to_virt(const unsigned int idx)
129 * this branch gets completely eliminated after inlining,
130 * except when someone tries to use fixaddr indices in an
131 * illegal way. (such as mixing up address types or using
132 * out-of-range indices).
134 * If it doesn't get removed, the linker will complain
135 * loudly with a reasonably clear error message..
137 if (idx >= __end_of_fixed_addresses)
138 __this_fixmap_does_not_exist();
140 return __fix_to_virt(idx);
143 static inline unsigned long virt_to_fix(const unsigned long vaddr)
145 BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
146 return __virt_to_fix(vaddr);
149 #endif /* !__ASSEMBLY__ */