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          * If necessary we round it up to the next 256 pages boundary so
 122          * that we 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 #define TOTAL_FIX_BTMAPS        (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
 127         FIX_BTMAP_END =
 128          (__end_of_permanent_fixed_addresses ^
 129           (__end_of_permanent_fixed_addresses + TOTAL_FIX_BTMAPS - 1)) &
 130          -PTRS_PER_PTE
 131          ? __end_of_permanent_fixed_addresses + TOTAL_FIX_BTMAPS -
 132            (__end_of_permanent_fixed_addresses & (TOTAL_FIX_BTMAPS - 1))
 133          : __end_of_permanent_fixed_addresses,
 134         FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
 135 #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
 136         FIX_OHCI1394_BASE,
 137 #endif
 138 #ifdef CONFIG_X86_32
 139         FIX_WP_TEST,
 140 #endif
 141 #ifdef CONFIG_INTEL_TXT
 142         FIX_TBOOT_BASE,
 143 #endif
 144         __end_of_fixed_addresses
 145 };
 146
 147
 148 extern void reserve_top_address(unsigned long reserve);
 149
 150 #define FIXADDR_SIZE    (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
 151 #define FIXADDR_BOOT_SIZE       (__end_of_fixed_addresses << PAGE_SHIFT)
 152 #define FIXADDR_START           (FIXADDR_TOP - FIXADDR_SIZE)
 153 #define FIXADDR_BOOT_START      (FIXADDR_TOP - FIXADDR_BOOT_SIZE)
 154
 155 extern int fixmaps_set;
 156
 157 extern pte_t *kmap_pte;
 158 extern pgprot_t kmap_prot;
 159 extern pte_t *pkmap_page_table;
 160
 161 void __native_set_fixmap(enum fixed_addresses idx, pte_t pte);
 162 void native_set_fixmap(enum fixed_addresses idx,
 163                        phys_addr_t phys, pgprot_t flags);
 164
 165 #ifndef CONFIG_PARAVIRT
 166 static inline void __set_fixmap(enum fixed_addresses idx,
 167                                 phys_addr_t phys, pgprot_t flags)
 168 {
 169         native_set_fixmap(idx, phys, flags);
 170 }
 171 #endif
 172
 173 #define set_fixmap(idx, phys)                           \
 174         __set_fixmap(idx, phys, PAGE_KERNEL)
 175
 176 /*
 177  * Some hardware wants to get fixmapped without caching.
 178  */
 179 #define set_fixmap_nocache(idx, phys)                   \
 180         __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
 181
 182 #define clear_fixmap(idx)                       \
 183         __set_fixmap(idx, 0, __pgprot(0))
 184
 185 #define __fix_to_virt(x)        (FIXADDR_TOP - ((x) << PAGE_SHIFT))
 186 #define __virt_to_fix(x)        ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
 187
 188 extern void __this_fixmap_does_not_exist(void);
 189
 190 /*
 191  * 'index to address' translation. If anyone tries to use the idx
 192  * directly without translation, we catch the bug with a NULL-deference
 193  * kernel oops. Illegal ranges of incoming indices are caught too.
 194  */
 195 static __always_inline unsigned long fix_to_virt(const unsigned int idx)
 196 {
 197         /*
 198          * this branch gets completely eliminated after inlining,
 199          * except when someone tries to use fixaddr indices in an
 200          * illegal way. (such as mixing up address types or using
 201          * out-of-range indices).
 202          *
 203          * If it doesn't get removed, the linker will complain
 204          * loudly with a reasonably clear error message..
 205          */
 206         if (idx >= __end_of_fixed_addresses)
 207                 __this_fixmap_does_not_exist();
 208
 209         return __fix_to_virt(idx);
 210 }
 211
 212 static inline unsigned long virt_to_fix(const unsigned long vaddr)
 213 {
 214         BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
 215         return __virt_to_fix(vaddr);
 216 }
 217 #endif /* !__ASSEMBLY__ */
 218 #endif /* _ASM_X86_FIXMAP_H */