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