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