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 extern unsigned long __FIXADDR_TOP;
  23 #define FIXADDR_USER_START     __fix_to_virt(FIX_VDSO)
  24 #define FIXADDR_USER_END       __fix_to_virt(FIX_VDSO - 1)
  25
  26 #ifndef __ASSEMBLY__
  27 #include <linux/kernel.h>
  28 #include <asm/acpi.h>
  29 #include <asm/apicdef.h>
  30 #include <asm/page.h>
  31 #ifdef CONFIG_HIGHMEM
  32 #include <linux/threads.h>
  33 #include <asm/kmap_types.h>
  34 #endif
  35
  36 /*
  37  * Here we define all the compile-time 'special' virtual
  38  * addresses. The point is to have a constant address at
  39  * compile time, but to set the physical address only
  40  * in the boot process. We allocate these special addresses
  41  * from the end of virtual memory (0xfffff000) backwards.
  42  * Also this lets us do fail-safe vmalloc(), we
  43  * can guarantee that these special addresses and
  44  * vmalloc()-ed addresses never overlap.
  45  *
  46  * these 'compile-time allocated' memory buffers are
  47  * fixed-size 4k pages. (or larger if used with an increment
  48  * highger than 1) use fixmap_set(idx,phys) to associate
  49  * physical memory with fixmap indices.
  50  *
  51  * TLB entries of such buffers will not be flushed across
  52  * task switches.
  53  */
  54 enum fixed_addresses {
  55         FIX_HOLE,
  56         FIX_VDSO,
  57         FIX_DBGP_BASE,
  58         FIX_EARLYCON_MEM_BASE,
  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 #ifdef CONFIG_PARAVIRT
  90         FIX_PARAVIRT_BOOTMAP,
  91 #endif
  92         __end_of_permanent_fixed_addresses,
  93         /* temporary boot-time mappings, used before ioremap() is functional */
  94 #define NR_FIX_BTMAPS   16
  95         FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
  96         FIX_BTMAP_BEGIN = FIX_BTMAP_END + NR_FIX_BTMAPS - 1,
  97         FIX_WP_TEST,
  98         __end_of_fixed_addresses
  99 };
 100
 101 extern void __set_fixmap (enum fixed_addresses idx,
 102                                         unsigned long phys, pgprot_t flags);
 103 extern void reserve_top_address(unsigned long reserve);
 104
 105 #define set_fixmap(idx, phys) \
 106                 __set_fixmap(idx, phys, PAGE_KERNEL)
 107 /*
 108  * Some hardware wants to get fixmapped without caching.
 109  */
 110 #define set_fixmap_nocache(idx, phys) \
 111                 __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
 112
 113 #define clear_fixmap(idx) \
 114                 __set_fixmap(idx, 0, __pgprot(0))
 115
 116 #define FIXADDR_TOP     ((unsigned long)__FIXADDR_TOP)
 117
 118 #define __FIXADDR_SIZE  (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
 119 #define __FIXADDR_BOOT_SIZE     (__end_of_fixed_addresses << PAGE_SHIFT)
 120 #define FIXADDR_START           (FIXADDR_TOP - __FIXADDR_SIZE)
 121 #define FIXADDR_BOOT_START      (FIXADDR_TOP - __FIXADDR_BOOT_SIZE)
 122
 123 #define __fix_to_virt(x)        (FIXADDR_TOP - ((x) << PAGE_SHIFT))
 124 #define __virt_to_fix(x)        ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
 125
 126 extern void __this_fixmap_does_not_exist(void);
 127
 128 /*
 129  * 'index to address' translation. If anyone tries to use the idx
 130  * directly without tranlation, we catch the bug with a NULL-deference
 131  * kernel oops. Illegal ranges of incoming indices are caught too.
 132  */
 133 static __always_inline unsigned long fix_to_virt(const unsigned int idx)
 134 {
 135         /*
 136          * this branch gets completely eliminated after inlining,
 137          * except when someone tries to use fixaddr indices in an
 138          * illegal way. (such as mixing up address types or using
 139          * out-of-range indices).
 140          *
 141          * If it doesn't get removed, the linker will complain
 142          * loudly with a reasonably clear error message..
 143          */
 144         if (idx >= __end_of_fixed_addresses)
 145                 __this_fixmap_does_not_exist();
 146
 147         return __fix_to_virt(idx);
 148 }
 149
 150 static inline unsigned long virt_to_fix(const unsigned long vaddr)
 151 {
 152         BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
 153         return __virt_to_fix(vaddr);
 154 }
 155
 156 #endif /* !__ASSEMBLY__ */
 157 #endif