LXR linux-bk/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#include <linux/kernel.h>
  18#include <asm/acpi.h>
  19#include <asm/apicdef.h>
  20#include <asm/page.h>
  21#ifdef CONFIG_HIGHMEM
  22#include <linux/threads.h>
  23#include <asm/kmap_types.h>
  24#endif
  25
  26/*
  27 * Here we define all the compile-time 'special' virtual
  28 * addresses. The point is to have a constant address at
  29 * compile time, but to set the physical address only
  30 * in the boot process. We allocate these special addresses
  31 * from the end of virtual memory (0xfffff000) backwards.
  32 * Also this lets us do fail-safe vmalloc(), we
  33 * can guarantee that these special addresses and
  34 * vmalloc()-ed addresses never overlap.
  35 *
  36 * these 'compile-time allocated' memory buffers are
  37 * fixed-size 4k pages. (or larger if used with an increment
  38 * highger than 1) use fixmap_set(idx,phys) to associate
  39 * physical memory with fixmap indices.
  40 *
  41 * TLB entries of such buffers will not be flushed across
  42 * task switches.
  43 */
  44enum fixed_addresses {
  45        FIX_HOLE,
  46        FIX_VSYSCALL,
  47#ifdef CONFIG_X86_LOCAL_APIC
  48        FIX_APIC_BASE,  /* local (CPU) APIC) -- required for SMP or not */
  49#endif
  50#ifdef CONFIG_X86_IO_APIC
  51        FIX_IO_APIC_BASE_0,
  52        FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS-1,
  53#endif
  54#ifdef CONFIG_X86_VISWS_APIC
  55        FIX_CO_CPU,     /* Cobalt timer */
  56        FIX_CO_APIC,    /* Cobalt APIC Redirection Table */ 
  57        FIX_LI_PCIA,    /* Lithium PCI Bridge A */
  58        FIX_LI_PCIB,    /* Lithium PCI Bridge B */
  59#endif
  60#ifdef CONFIG_X86_F00F_BUG
  61        FIX_F00F_IDT,   /* Virtual mapping for IDT */
  62#endif
  63#ifdef CONFIG_X86_CYCLONE_TIMER
  64        FIX_CYCLONE_TIMER, /*cyclone timer register*/
  65#endif 
  66#ifdef CONFIG_HIGHMEM
  67        FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
  68        FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
  69#endif
  70#ifdef CONFIG_ACPI_BOOT
  71        FIX_ACPI_BEGIN,
  72        FIX_ACPI_END = FIX_ACPI_BEGIN + FIX_ACPI_PAGES - 1,
  73#endif
  74#ifdef CONFIG_PCI_MMCONFIG
  75        FIX_PCIE_MCFG,
  76#endif
  77        __end_of_permanent_fixed_addresses,
  78        /* temporary boot-time mappings, used before ioremap() is functional */
  79#define NR_FIX_BTMAPS   16
  80        FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
  81        FIX_BTMAP_BEGIN = FIX_BTMAP_END + NR_FIX_BTMAPS - 1,
  82        FIX_WP_TEST,
  83        __end_of_fixed_addresses
  84};
  85
  86extern void __set_fixmap (enum fixed_addresses idx,
  87                                        unsigned long phys, pgprot_t flags);
  88
  89#define set_fixmap(idx, phys) \
  90                __set_fixmap(idx, phys, PAGE_KERNEL)
  91/*
  92 * Some hardware wants to get fixmapped without caching.
  93 */
  94#define set_fixmap_nocache(idx, phys) \
  95                __set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
  96
  97#define clear_fixmap(idx) \
  98                __set_fixmap(idx, 0, __pgprot(0))
  99
 100/*
 101 * used by vmalloc.c.
 102 *
 103 * Leave one empty page between vmalloc'ed areas and
 104 * the start of the fixmap.
 105 */
 106#define FIXADDR_TOP     (0xfffff000UL)
 107#define __FIXADDR_SIZE  (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
 108#define FIXADDR_START   (FIXADDR_TOP - __FIXADDR_SIZE)
 109
 110#define __fix_to_virt(x)        (FIXADDR_TOP - ((x) << PAGE_SHIFT))
 111#define __virt_to_fix(x)        ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
 112
 113/*
 114 * This is the range that is readable by user mode, and things
 115 * acting like user mode such as get_user_pages.
 116 */
 117#define FIXADDR_USER_START      (__fix_to_virt(FIX_VSYSCALL))
 118#define FIXADDR_USER_END        (FIXADDR_USER_START + PAGE_SIZE)
 119
 120
 121extern void __this_fixmap_does_not_exist(void);
 122
 123/*
 124 * 'index to address' translation. If anyone tries to use the idx
 125 * directly without tranlation, we catch the bug with a NULL-deference
 126 * kernel oops. Illegal ranges of incoming indices are caught too.
 127 */
 128static inline unsigned long fix_to_virt(const unsigned int idx)
 129{
 130        /*
 131         * this branch gets completely eliminated after inlining,
 132         * except when someone tries to use fixaddr indices in an
 133         * illegal way. (such as mixing up address types or using
 134         * out-of-range indices).
 135         *
 136         * If it doesn't get removed, the linker will complain
 137         * loudly with a reasonably clear error message..
 138         */
 139        if (idx >= __end_of_fixed_addresses)
 140                __this_fixmap_does_not_exist();
 141
 142        return __fix_to_virt(idx);
 143}
 144
 145static inline unsigned long virt_to_fix(const unsigned long vaddr)
 146{
 147        BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
 148        return __virt_to_fix(vaddr);
 149}
 150
 151#endif
 152