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
11 * x86_32 and x86_64 integration by Gustavo F. Padovan, February 2009
14 #ifndef _ASM_X86_FIXMAP_H
15 #define _ASM_X86_FIXMAP_H
18 #include <linux/kernel.h>
22 #include <linux/threads.h>
23 #include <asm/kmap_types.h>
25 #include <asm/vsyscall.h>
29 * We can't declare FIXADDR_TOP as variable for x86_64 because vsyscall
30 * uses fixmaps that relies on FIXADDR_TOP for proper address calculation.
31 * Because of this, FIXADDR_TOP x86 integration was left as later work.
34 /* used by vmalloc.c, vsyscall.lds.S.
36 * Leave one empty page between vmalloc'ed areas and
37 * the start of the fixmap.
39 extern unsigned long __FIXADDR_TOP;
40 #define FIXADDR_TOP ((unsigned long)__FIXADDR_TOP)
42 #define FIXADDR_USER_START __fix_to_virt(FIX_VDSO)
43 #define FIXADDR_USER_END __fix_to_virt(FIX_VDSO - 1)
45 #define FIXADDR_TOP (VSYSCALL_END-PAGE_SIZE)
47 /* Only covers 32bit vsyscalls currently. Need another set for 64bit. */
48 #define FIXADDR_USER_START ((unsigned long)VSYSCALL32_VSYSCALL)
49 #define FIXADDR_USER_END (FIXADDR_USER_START + PAGE_SIZE)
54 * Here we define all the compile-time 'special' virtual
55 * addresses. The point is to have a constant address at
56 * compile time, but to set the physical address only
57 * in the boot process.
58 * for x86_32: We allocate these special addresses
59 * from the end of virtual memory (0xfffff000) backwards.
60 * Also this lets us do fail-safe vmalloc(), we
61 * can guarantee that these special addresses and
62 * vmalloc()-ed addresses never overlap.
64 * These 'compile-time allocated' memory buffers are
65 * fixed-size 4k pages (or larger if used with an increment
66 * higher than 1). Use set_fixmap(idx,phys) to associate
67 * physical memory with fixmap indices.
69 * TLB entries of such buffers will not be flushed across
72 enum fixed_addresses {
78 VSYSCALL_FIRST_PAGE = VSYSCALL_LAST_PAGE
79 + ((VSYSCALL_END-VSYSCALL_START) >> PAGE_SHIFT) - 1,
83 FIX_EARLYCON_MEM_BASE,
84 #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
88 #ifdef CONFIG_X86_LOCAL_APIC
89 FIX_APIC_BASE, /* local (CPU) APIC) -- required for SMP or not */
91 #ifdef CONFIG_X86_IO_APIC
93 FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS - 1,
97 #define NR_FIX_ISAMAPS 256
99 FIX_ISAMAP_BEGIN = FIX_ISAMAP_END + NR_FIX_ISAMAPS - 1,
101 #ifdef CONFIG_X86_VISWS_APIC
102 FIX_CO_CPU, /* Cobalt timer */
103 FIX_CO_APIC, /* Cobalt APIC Redirection Table */
104 FIX_LI_PCIA, /* Lithium PCI Bridge A */
105 FIX_LI_PCIB, /* Lithium PCI Bridge B */
107 #ifdef CONFIG_X86_F00F_BUG
108 FIX_F00F_IDT, /* Virtual mapping for IDT */
110 #ifdef CONFIG_X86_CYCLONE_TIMER
111 FIX_CYCLONE_TIMER, /*cyclone timer register*/
114 FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
115 FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
116 #ifdef CONFIG_PCI_MMCONFIG
120 #ifdef CONFIG_PARAVIRT
121 FIX_PARAVIRT_BOOTMAP,
123 FIX_TEXT_POKE1, /* reserve 2 pages for text_poke() */
124 FIX_TEXT_POKE0, /* first page is last, because allocation is backward */
125 __end_of_permanent_fixed_addresses,
127 * 256 temporary boot-time mappings, used by early_ioremap(),
128 * before ioremap() is functional.
130 * If necessary we round it up to the next 256 pages boundary so
131 * that we can have a single pgd entry and a single pte table:
133 #define NR_FIX_BTMAPS 64
134 #define FIX_BTMAPS_SLOTS 4
135 #define TOTAL_FIX_BTMAPS (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
137 (__end_of_permanent_fixed_addresses ^
138 (__end_of_permanent_fixed_addresses + TOTAL_FIX_BTMAPS - 1)) &
140 ? __end_of_permanent_fixed_addresses + TOTAL_FIX_BTMAPS -
141 (__end_of_permanent_fixed_addresses & (TOTAL_FIX_BTMAPS - 1))
142 : __end_of_permanent_fixed_addresses,
143 FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
147 #ifdef CONFIG_INTEL_TXT
150 __end_of_fixed_addresses
154 extern void reserve_top_address(unsigned long reserve);
156 #define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
157 #define FIXADDR_BOOT_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
158 #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
159 #define FIXADDR_BOOT_START (FIXADDR_TOP - FIXADDR_BOOT_SIZE)
161 extern int fixmaps_set;
163 extern pte_t *kmap_pte;
164 extern pgprot_t kmap_prot;
165 extern pte_t *pkmap_page_table;
167 void xen_set_fixmap(enum fixed_addresses, phys_addr_t, pgprot_t);
169 static inline void __set_fixmap(enum fixed_addresses idx,
170 phys_addr_t phys, pgprot_t flags)
172 xen_set_fixmap(idx, phys, flags);
175 #define set_fixmap(idx, phys) \
176 __set_fixmap(idx, phys, PAGE_KERNEL)
179 * Some hardware wants to get fixmapped without caching.
181 #define set_fixmap_nocache(idx, phys) \
182 __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
184 #define clear_fixmap(idx) \
185 __set_fixmap(idx, 0, __pgprot(0))
187 #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
188 #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
190 extern void __this_fixmap_does_not_exist(void);
193 * 'index to address' translation. If anyone tries to use the idx
194 * directly without translation, we catch the bug with a NULL-deference
195 * kernel oops. Illegal ranges of incoming indices are caught too.
197 static __always_inline unsigned long fix_to_virt(const unsigned int idx)
200 * this branch gets completely eliminated after inlining,
201 * except when someone tries to use fixaddr indices in an
202 * illegal way. (such as mixing up address types or using
203 * out-of-range indices).
205 * If it doesn't get removed, the linker will complain
206 * loudly with a reasonably clear error message..
208 if (idx >= __end_of_fixed_addresses)
209 __this_fixmap_does_not_exist();
211 return __fix_to_virt(idx);
214 static inline unsigned long virt_to_fix(const unsigned long vaddr)
216 BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
217 return __virt_to_fix(vaddr);
219 #endif /* !__ASSEMBLY__ */
220 #endif /* _ASM_X86_FIXMAP_H */