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>
18 /* used by vmalloc.c, vsyscall.lds.S.
20 * Leave one empty page between vmalloc'ed areas and
21 * the start of the fixmap.
23 extern unsigned long __FIXADDR_TOP;
26 #include <linux/kernel.h>
28 #include <asm/apicdef.h>
30 #include <xen/gnttab.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 {
57 #ifdef CONFIG_X86_LOCAL_APIC
58 FIX_APIC_BASE, /* local (CPU) APIC) -- required for SMP or not */
60 #ifdef CONFIG_X86_IO_APIC
62 FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS-1,
64 #ifdef CONFIG_X86_VISWS_APIC
65 FIX_CO_CPU, /* Cobalt timer */
66 FIX_CO_APIC, /* Cobalt APIC Redirection Table */
67 FIX_LI_PCIA, /* Lithium PCI Bridge A */
68 FIX_LI_PCIB, /* Lithium PCI Bridge B */
70 #ifdef CONFIG_X86_F00F_BUG
71 FIX_F00F_IDT, /* Virtual mapping for IDT */
73 #ifdef CONFIG_X86_CYCLONE_TIMER
74 FIX_CYCLONE_TIMER, /*cyclone timer register*/
77 FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
78 FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
82 FIX_ACPI_END = FIX_ACPI_BEGIN + FIX_ACPI_PAGES - 1,
84 #ifdef CONFIG_PCI_MMCONFIG
88 #define NR_FIX_ISAMAPS 256
90 FIX_ISAMAP_BEGIN = FIX_ISAMAP_END + NR_FIX_ISAMAPS - 1,
91 __end_of_permanent_fixed_addresses,
92 /* temporary boot-time mappings, used before ioremap() is functional */
93 #define NR_FIX_BTMAPS 16
94 FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
95 FIX_BTMAP_BEGIN = FIX_BTMAP_END + NR_FIX_BTMAPS - 1,
97 __end_of_fixed_addresses
100 extern void __set_fixmap(enum fixed_addresses idx,
101 maddr_t phys, pgprot_t flags);
103 extern void set_fixaddr_top(unsigned long top);
105 #define set_fixmap(idx, phys) \
106 __set_fixmap(idx, phys, PAGE_KERNEL)
108 * Some hardware wants to get fixmapped without caching.
110 #define set_fixmap_nocache(idx, phys) \
111 __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
113 #define clear_fixmap(idx) \
114 __set_fixmap(idx, 0, __pgprot(0))
116 #define FIXADDR_TOP ((unsigned long)__FIXADDR_TOP)
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)
123 #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
124 #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
127 * This is the range that is readable by user mode, and things
128 * acting like user mode such as get_user_pages.
130 #define FIXADDR_USER_START (__fix_to_virt(FIX_VSYSCALL))
131 #define FIXADDR_USER_END (FIXADDR_USER_START + PAGE_SIZE)
134 extern void __this_fixmap_does_not_exist(void);
137 * 'index to address' translation. If anyone tries to use the idx
138 * directly without tranlation, we catch the bug with a NULL-deference
139 * kernel oops. Illegal ranges of incoming indices are caught too.
141 static __always_inline unsigned long fix_to_virt(const unsigned int idx)
144 * this branch gets completely eliminated after inlining,
145 * except when someone tries to use fixaddr indices in an
146 * illegal way. (such as mixing up address types or using
147 * out-of-range indices).
149 * If it doesn't get removed, the linker will complain
150 * loudly with a reasonably clear error message..
152 if (idx >= __end_of_fixed_addresses)
153 __this_fixmap_does_not_exist();
155 return __fix_to_virt(idx);
158 static inline unsigned long virt_to_fix(const unsigned long vaddr)
160 BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
161 return __virt_to_fix(vaddr);
164 #endif /* !__ASSEMBLY__ */