include/asm-i386/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  */
  12
  13 #ifndef _ASM_FIXMAP_H
  14 #define _ASM_FIXMAP_H
  15
  16 #include <linux/config.h>
  17
  18 /* used by vmalloc.c, vsyscall.lds.S.
  19  *
  20  * Leave one empty page between vmalloc'ed areas and
  21  * the start of the fixmap.
  22  */
  23 #define __FIXADDR_TOP   0xfffff000
  24
  25 #ifndef __ASSEMBLY__
  26 #include <linux/kernel.h>
  27 #include <asm/acpi.h>
  28 #include <asm/apicdef.h>
  29 #include <asm/page.h>
  30 #ifdef CONFIG_HIGHMEM
  31 #include <linux/threads.h>
  32 #include <asm/kmap_types.h>
  33 #endif
  34
  35 /*
  36  * Here we define all the compile-time 'special' virtual
  37  * addresses. The point is to have a constant address at
  38  * compile time, but to set the physical address only
  39  * in the boot process. We allocate these special addresses
  40  * from the end of virtual memory (0xfffff000) backwards.
  41  * Also this lets us do fail-safe vmalloc(), we
  42  * can guarantee that these special addresses and
  43  * vmalloc()-ed addresses never overlap.
  44  *
  45  * these 'compile-time allocated' memory buffers are
  46  * fixed-size 4k pages. (or larger if used with an increment
  47  * highger than 1) use fixmap_set(idx,phys) to associate
  48  * physical memory with fixmap indices.
  49  *
  50  * TLB entries of such buffers will not be flushed across
  51  * task switches.
  52  */
  53 enum fixed_addresses {
  54         FIX_HOLE,
  55         FIX_VSYSCALL,
  56 #ifdef CONFIG_X86_LOCAL_APIC
  57         FIX_APIC_BASE,  /* local (CPU) APIC) -- required for SMP or not */
  58 #endif
  59 #ifdef CONFIG_X86_IO_APIC
  60         FIX_IO_APIC_BASE_0,
  61         FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS-1,
  62 #endif
  63 #ifdef CONFIG_X86_VISWS_APIC
  64         FIX_CO_CPU,     /* Cobalt timer */
  65         FIX_CO_APIC,    /* Cobalt APIC Redirection Table */
  66         FIX_LI_PCIA,    /* Lithium PCI Bridge A */
  67         FIX_LI_PCIB,    /* Lithium PCI Bridge B */
  68 #endif
  69 #ifdef CONFIG_X86_F00F_BUG
  70         FIX_F00F_IDT,   /* Virtual mapping for IDT */
  71 #endif
  72 #ifdef CONFIG_X86_CYCLONE_TIMER
  73         FIX_CYCLONE_TIMER, /*cyclone timer register*/
  74 #endif
  75 #ifdef CONFIG_HIGHMEM
  76         FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
  77         FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
  78 #endif
  79 #ifdef CONFIG_ACPI_BOOT
  80         FIX_ACPI_BEGIN,
  81         FIX_ACPI_END = FIX_ACPI_BEGIN + FIX_ACPI_PAGES - 1,
  82 #endif
  83 #ifdef CONFIG_PCI_MMCONFIG
  84         FIX_PCIE_MCFG,
  85 #endif
  86         __end_of_permanent_fixed_addresses,
  87         /* temporary boot-time mappings, used before ioremap() is functional */
  88 #define NR_FIX_BTMAPS   16
  89         FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
  90         FIX_BTMAP_BEGIN = FIX_BTMAP_END + NR_FIX_BTMAPS - 1,
  91         FIX_WP_TEST,
  92         __end_of_fixed_addresses
  93 };
  94
  95 extern void __set_fixmap (enum fixed_addresses idx,
  96                                         unsigned long phys, pgprot_t flags);
  97
  98 #define set_fixmap(idx, phys) \
  99                 __set_fixmap(idx, phys, PAGE_KERNEL)
 100 /*
 101  * Some hardware wants to get fixmapped without caching.
 102  */
 103 #define set_fixmap_nocache(idx, phys) \
 104                 __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
 105
 106 #define clear_fixmap(idx) \
 107                 __set_fixmap(idx, 0, __pgprot(0))
 108
 109 #define FIXADDR_TOP     ((unsigned long)__FIXADDR_TOP)
 110
 111 #define __FIXADDR_SIZE  (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
 112 #define __FIXADDR_BOOT_SIZE     (__end_of_fixed_addresses << PAGE_SHIFT)
 113 #define FIXADDR_START           (FIXADDR_TOP - __FIXADDR_SIZE)
 114 #define FIXADDR_BOOT_START      (FIXADDR_TOP - __FIXADDR_BOOT_SIZE)
 115
 116 #define __fix_to_virt(x)        (FIXADDR_TOP - ((x) << PAGE_SHIFT))
 117 #define __virt_to_fix(x)        ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
 118
 119 /*
 120  * This is the range that is readable by user mode, and things
 121  * acting like user mode such as get_user_pages.
 122  */
 123 #define FIXADDR_USER_START      (__fix_to_virt(FIX_VSYSCALL))
 124 #define FIXADDR_USER_END        (FIXADDR_USER_START + PAGE_SIZE)
 125
 126
 127 extern void __this_fixmap_does_not_exist(void);
 128
 129 /*
 130  * 'index to address' translation. If anyone tries to use the idx
 131  * directly without tranlation, we catch the bug with a NULL-deference
 132  * kernel oops. Illegal ranges of incoming indices are caught too.
 133  */
 134 static __always_inline unsigned long fix_to_virt(const unsigned int idx)
 135 {
 136         /*
 137          * this branch gets completely eliminated after inlining,
 138          * except when someone tries to use fixaddr indices in an
 139          * illegal way. (such as mixing up address types or using
 140          * out-of-range indices).
 141          *
 142          * If it doesn't get removed, the linker will complain
 143          * loudly with a reasonably clear error message..
 144          */
 145         if (idx >= __end_of_fixed_addresses)
 146                 __this_fixmap_does_not_exist();
 147
 148         return __fix_to_virt(idx);
 149 }
 150
 151 static inline unsigned long virt_to_fix(const unsigned long vaddr)
 152 {
 153         BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
 154         return __virt_to_fix(vaddr);
 155 }
 156
 157 #endif /* !__ASSEMBLY__ */
 158 #endif