arch/x86/include/asm/fixmap.h

   1 /*
   2  * fixmap.h: compile-time virtual memory allocation
   3  *
   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
   6  * for more details.
   7  *
   8  * Copyright (C) 1998 Ingo Molnar
   9  *
  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
  12  */
  13
  14 #ifndef _ASM_X86_FIXMAP_H
  15 #define _ASM_X86_FIXMAP_H
  16
  17 #ifndef __ASSEMBLY__
  18 #include <linux/kernel.h>
  19 #include <asm/acpi.h>
  20 #include <asm/apicdef.h>
  21 #include <asm/page.h>
  22 #ifdef CONFIG_X86_32
  23 #include <linux/threads.h>
  24 #include <asm/kmap_types.h>
  25 #else
  26 #include <asm/vsyscall.h>
  27 #endif
  28
  29 /*
  30  * We can't declare FIXADDR_TOP as variable for x86_64 because vsyscall
  31  * uses fixmaps that relies on FIXADDR_TOP for proper address calculation.
  32  * Because of this, FIXADDR_TOP x86 integration was left as later work.
  33  */
  34 #ifdef CONFIG_X86_32
  35 /* used by vmalloc.c, vsyscall.lds.S.
  36  *
  37  * Leave one empty page between vmalloc'ed areas and
  38  * the start of the fixmap.
  39  */
  40 extern unsigned long __FIXADDR_TOP;
  41 #define FIXADDR_TOP     ((unsigned long)__FIXADDR_TOP)
  42
  43 #define FIXADDR_USER_START     __fix_to_virt(FIX_VDSO)
  44 #define FIXADDR_USER_END       __fix_to_virt(FIX_VDSO - 1)
  45 #else
  46 #define FIXADDR_TOP     (VSYSCALL_END-PAGE_SIZE)
  47
  48 /* Only covers 32bit vsyscalls currently. Need another set for 64bit. */
  49 #define FIXADDR_USER_START      ((unsigned long)VSYSCALL32_VSYSCALL)
  50 #define FIXADDR_USER_END        (FIXADDR_USER_START + PAGE_SIZE)
  51 #endif
  52
  53
  54 /*
  55  * Here we define all the compile-time 'special' virtual
  56  * addresses. The point is to have a constant address at
  57  * compile time, but to set the physical address only
  58  * in the boot process.
  59  * for x86_32: We allocate these special addresses
  60  * from the end of virtual memory (0xfffff000) backwards.
  61  * Also this lets us do fail-safe vmalloc(), we
  62  * can guarantee that these special addresses and
  63  * vmalloc()-ed addresses never overlap.
  64  *
  65  * These 'compile-time allocated' memory buffers are
  66  * fixed-size 4k pages (or larger if used with an increment
  67  * higher than 1). Use set_fixmap(idx,phys) to associate
  68  * physical memory with fixmap indices.
  69  *
  70  * TLB entries of such buffers will not be flushed across
  71  * task switches.
  72  */
  73 enum fixed_addresses {
  74 #ifdef CONFIG_X86_32
  75         FIX_HOLE,
  76         FIX_VDSO,
  77 #else
  78         VSYSCALL_LAST_PAGE,
  79         VSYSCALL_FIRST_PAGE = VSYSCALL_LAST_PAGE
  80                             + ((VSYSCALL_END-VSYSCALL_START) >> PAGE_SHIFT) - 1,
  81         VSYSCALL_HPET,
  82 #endif
  83         FIX_DBGP_BASE,
  84         FIX_EARLYCON_MEM_BASE,
  85 #ifdef CONFIG_X86_LOCAL_APIC
  86         FIX_APIC_BASE,  /* local (CPU) APIC) -- required for SMP or not */
  87 #endif
  88 #ifdef CONFIG_X86_IO_APIC
  89         FIX_IO_APIC_BASE_0,
  90         FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS - 1,
  91 #endif
  92 #ifdef CONFIG_X86_VISWS_APIC
  93         FIX_CO_CPU,     /* Cobalt timer */
  94         FIX_CO_APIC,    /* Cobalt APIC Redirection Table */
  95         FIX_LI_PCIA,    /* Lithium PCI Bridge A */
  96         FIX_LI_PCIB,    /* Lithium PCI Bridge B */
  97 #endif
  98 #ifdef CONFIG_X86_F00F_BUG
  99         FIX_F00F_IDT,   /* Virtual mapping for IDT */
 100 #endif
 101 #ifdef CONFIG_X86_CYCLONE_TIMER
 102         FIX_CYCLONE_TIMER, /*cyclone timer register*/
 103 #endif
 104 #ifdef CONFIG_X86_32
 105         FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
 106         FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
 107 #ifdef CONFIG_PCI_MMCONFIG
 108         FIX_PCIE_MCFG,
 109 #endif
 110 #endif
 111 #ifdef CONFIG_PARAVIRT
 112         FIX_PARAVIRT_BOOTMAP,
 113 #endif
 114         FIX_TEXT_POKE1, /* reserve 2 pages for text_poke() */
 115         FIX_TEXT_POKE0, /* first page is last, because allocation is backward */
 116         __end_of_permanent_fixed_addresses,
 117         /*
 118          * 256 temporary boot-time mappings, used by early_ioremap(),
 119          * before ioremap() is functional.
 120          *
 121          * We round it up to the next 256 pages boundary so that we
 122          * can have a single pgd entry and a single pte table:
 123          */
 124 #define NR_FIX_BTMAPS           64
 125 #define FIX_BTMAPS_SLOTS        4
 126         FIX_BTMAP_END = __end_of_permanent_fixed_addresses + 256 -
 127                         (__end_of_permanent_fixed_addresses & 255),
 128         FIX_BTMAP_BEGIN = FIX_BTMAP_END + NR_FIX_BTMAPS*FIX_BTMAPS_SLOTS - 1,
 129 #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
 130         FIX_OHCI1394_BASE,
 131 #endif
 132 #ifdef CONFIG_X86_32
 133         FIX_WP_TEST,
 134 #endif
 135         __end_of_fixed_addresses
 136 };
 137
 138
 139 extern void reserve_top_address(unsigned long reserve);
 140
 141 #define FIXADDR_SIZE    (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
 142 #define FIXADDR_BOOT_SIZE       (__end_of_fixed_addresses << PAGE_SHIFT)
 143 #define FIXADDR_START           (FIXADDR_TOP - FIXADDR_SIZE)
 144 #define FIXADDR_BOOT_START      (FIXADDR_TOP - FIXADDR_BOOT_SIZE)
 145
 146 extern int fixmaps_set;
 147
 148 extern pte_t *kmap_pte;
 149 extern pgprot_t kmap_prot;
 150 extern pte_t *pkmap_page_table;
 151
 152 void __native_set_fixmap(enum fixed_addresses idx, pte_t pte);
 153 void native_set_fixmap(enum fixed_addresses idx,
 154                        phys_addr_t phys, pgprot_t flags);
 155
 156 #ifndef CONFIG_PARAVIRT
 157 static inline void __set_fixmap(enum fixed_addresses idx,
 158                                 phys_addr_t phys, pgprot_t flags)
 159 {
 160         native_set_fixmap(idx, phys, flags);
 161 }
 162 #endif
 163
 164 #define set_fixmap(idx, phys)                           \
 165         __set_fixmap(idx, phys, PAGE_KERNEL)
 166
 167 /*
 168  * Some hardware wants to get fixmapped without caching.
 169  */
 170 #define set_fixmap_nocache(idx, phys)                   \
 171         __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
 172
 173 #define clear_fixmap(idx)                       \
 174         __set_fixmap(idx, 0, __pgprot(0))
 175
 176 #define __fix_to_virt(x)        (FIXADDR_TOP - ((x) << PAGE_SHIFT))
 177 #define __virt_to_fix(x)        ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
 178
 179 extern void __this_fixmap_does_not_exist(void);
 180
 181 /*
 182  * 'index to address' translation. If anyone tries to use the idx
 183  * directly without translation, we catch the bug with a NULL-deference
 184  * kernel oops. Illegal ranges of incoming indices are caught too.
 185  */
 186 static __always_inline unsigned long fix_to_virt(const unsigned int idx)
 187 {
 188         /*
 189          * this branch gets completely eliminated after inlining,
 190          * except when someone tries to use fixaddr indices in an
 191          * illegal way. (such as mixing up address types or using
 192          * out-of-range indices).
 193          *
 194          * If it doesn't get removed, the linker will complain
 195          * loudly with a reasonably clear error message..
 196          */
 197         if (idx >= __end_of_fixed_addresses)
 198                 __this_fixmap_does_not_exist();
 199
 200         return __fix_to_virt(idx);
 201 }
 202
 203 static inline unsigned long virt_to_fix(const unsigned long vaddr)
 204 {
 205         BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
 206         return __virt_to_fix(vaddr);
 207 }
 208 #endif /* !__ASSEMBLY__ */
 209 #endif /* _ASM_X86_FIXMAP_H */