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 #ifndef CONFIG_COMPAT_VDSO
23 extern unsigned long __FIXADDR_TOP;
25 #define __FIXADDR_TOP 0xfffff000
26 #define FIXADDR_USER_START __fix_to_virt(FIX_VDSO)
27 #define FIXADDR_USER_END __fix_to_virt(FIX_VDSO - 1)
31 #include <linux/kernel.h>
33 #include <asm/apicdef.h>
35 #include <xen/gnttab.h>
37 #include <linux/threads.h>
38 #include <asm/kmap_types.h>
42 * Here we define all the compile-time 'special' virtual
43 * addresses. The point is to have a constant address at
44 * compile time, but to set the physical address only
45 * in the boot process. We allocate these special addresses
46 * from the end of virtual memory (0xfffff000) backwards.
47 * Also this lets us do fail-safe vmalloc(), we
48 * can guarantee that these special addresses and
49 * vmalloc()-ed addresses never overlap.
51 * these 'compile-time allocated' memory buffers are
52 * fixed-size 4k pages. (or larger if used with an increment
53 * highger than 1) use fixmap_set(idx,phys) to associate
54 * physical memory with fixmap indices.
56 * TLB entries of such buffers will not be flushed across
59 enum fixed_addresses {
62 #ifdef CONFIG_X86_LOCAL_APIC
63 FIX_APIC_BASE, /* local (CPU) APIC) -- required for SMP or not */
65 #ifdef CONFIG_X86_IO_APIC
67 FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS-1,
69 #ifdef CONFIG_X86_VISWS_APIC
70 FIX_CO_CPU, /* Cobalt timer */
71 FIX_CO_APIC, /* Cobalt APIC Redirection Table */
72 FIX_LI_PCIA, /* Lithium PCI Bridge A */
73 FIX_LI_PCIB, /* Lithium PCI Bridge B */
75 #ifdef CONFIG_X86_F00F_BUG
76 FIX_F00F_IDT, /* Virtual mapping for IDT */
78 #ifdef CONFIG_X86_CYCLONE_TIMER
79 FIX_CYCLONE_TIMER, /*cyclone timer register*/
82 FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
83 FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
87 FIX_ACPI_END = FIX_ACPI_BEGIN + FIX_ACPI_PAGES - 1,
89 #ifdef CONFIG_PCI_MMCONFIG
93 #define NR_FIX_ISAMAPS 256
95 FIX_ISAMAP_BEGIN = FIX_ISAMAP_END + NR_FIX_ISAMAPS - 1,
96 __end_of_permanent_fixed_addresses,
97 /* temporary boot-time mappings, used before ioremap() is functional */
98 #define NR_FIX_BTMAPS 16
99 FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
100 FIX_BTMAP_BEGIN = FIX_BTMAP_END + NR_FIX_BTMAPS - 1,
102 __end_of_fixed_addresses
105 extern void __set_fixmap(enum fixed_addresses idx,
106 maddr_t phys, pgprot_t flags);
108 extern void reserve_top_address(unsigned long reserve);
109 extern void set_fixaddr_top(unsigned long top);
111 #define set_fixmap(idx, phys) \
112 __set_fixmap(idx, phys, PAGE_KERNEL)
114 * Some hardware wants to get fixmapped without caching.
116 #define set_fixmap_nocache(idx, phys) \
117 __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
119 #define clear_fixmap(idx) \
120 __set_fixmap(idx, 0, __pgprot(0))
122 #define FIXADDR_TOP ((unsigned long)__FIXADDR_TOP)
124 #define __FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
125 #define __FIXADDR_BOOT_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
126 #define FIXADDR_START (FIXADDR_TOP - __FIXADDR_SIZE)
127 #define FIXADDR_BOOT_START (FIXADDR_TOP - __FIXADDR_BOOT_SIZE)
129 #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
130 #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
132 extern void __this_fixmap_does_not_exist(void);
135 * 'index to address' translation. If anyone tries to use the idx
136 * directly without tranlation, we catch the bug with a NULL-deference
137 * kernel oops. Illegal ranges of incoming indices are caught too.
139 static __always_inline unsigned long fix_to_virt(const unsigned int idx)
142 * this branch gets completely eliminated after inlining,
143 * except when someone tries to use fixaddr indices in an
144 * illegal way. (such as mixing up address types or using
145 * out-of-range indices).
147 * If it doesn't get removed, the linker will complain
148 * loudly with a reasonably clear error message..
150 if (idx >= __end_of_fixed_addresses)
151 __this_fixmap_does_not_exist();
153 return __fix_to_virt(idx);
156 static inline unsigned long virt_to_fix(const unsigned long vaddr)
158 BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
159 return __virt_to_fix(vaddr);
162 #endif /* !__ASSEMBLY__ */