LXR linux/arch/tile/include/asm/fixmap.h

   1/*
   2 * Copyright (C) 1998 Ingo Molnar
   3 * Copyright 2010 Tilera Corporation. All Rights Reserved.
   4 *
   5 *   This program is free software; you can redistribute it and/or
   6 *   modify it under the terms of the GNU General Public License
   7 *   as published by the Free Software Foundation, version 2.
   8 *
   9 *   This program is distributed in the hope that it will be useful, but
  10 *   WITHOUT ANY WARRANTY; without even the implied warranty of
  11 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  12 *   NON INFRINGEMENT.  See the GNU General Public License for
  13 *   more details.
  14 */
  15
  16#ifndef _ASM_TILE_FIXMAP_H
  17#define _ASM_TILE_FIXMAP_H
  18
  19#include <asm/page.h>
  20
  21#ifndef __ASSEMBLY__
  22#include <linux/kernel.h>
  23#ifdef CONFIG_HIGHMEM
  24#include <linux/threads.h>
  25#include <asm/kmap_types.h>
  26#endif
  27
  28#define __fix_to_virt(x)        (FIXADDR_TOP - ((x) << PAGE_SHIFT))
  29#define __virt_to_fix(x)        ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
  30
  31/*
  32 * Here we define all the compile-time 'special' virtual
  33 * addresses. The point is to have a constant address at
  34 * compile time, but to set the physical address only
  35 * in the boot process. We allocate these special addresses
  36 * from the end of supervisor virtual memory backwards.
  37 * Also this lets us do fail-safe vmalloc(), we
  38 * can guarantee that these special addresses and
  39 * vmalloc()-ed addresses never overlap.
  40 *
  41 * these 'compile-time allocated' memory buffers are
  42 * fixed-size 4k pages. (or larger if used with an increment
  43 * higher than 1) use fixmap_set(idx,phys) to associate
  44 * physical memory with fixmap indices.
  45 *
  46 * TLB entries of such buffers will not be flushed across
  47 * task switches.
  48 */
  49enum fixed_addresses {
  50#ifdef __tilegx__
  51        /*
  52         * TILEPro has unmapped memory above so the hole isn't needed,
  53         * and in any case the hole pushes us over a single 16MB pmd.
  54         */
  55        FIX_HOLE,
  56#endif
  57#ifdef CONFIG_HIGHMEM
  58        FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
  59        FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
  60#endif
  61#ifdef __tilegx__  /* see homecache.c */
  62        FIX_HOMECACHE_BEGIN,
  63        FIX_HOMECACHE_END = FIX_HOMECACHE_BEGIN+(NR_CPUS)-1,
  64#endif
  65        __end_of_permanent_fixed_addresses,
  66
  67        /*
  68         * Temporary boot-time mappings, used before ioremap() is functional.
  69         * Not currently needed by the Tile architecture.
  70         */
  71#define NR_FIX_BTMAPS   0
  72#if NR_FIX_BTMAPS
  73        FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
  74        FIX_BTMAP_BEGIN = FIX_BTMAP_END + NR_FIX_BTMAPS - 1,
  75        __end_of_fixed_addresses
  76#else
  77        __end_of_fixed_addresses = __end_of_permanent_fixed_addresses
  78#endif
  79};
  80
  81extern void __set_fixmap(enum fixed_addresses idx,
  82                         unsigned long phys, pgprot_t flags);
  83
  84#define set_fixmap(idx, phys) \
  85                __set_fixmap(idx, phys, PAGE_KERNEL)
  86#define clear_fixmap(idx) \
  87                __set_fixmap(idx, 0, __pgprot(0))
  88
  89#define __FIXADDR_SIZE  (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
  90#define __FIXADDR_BOOT_SIZE     (__end_of_fixed_addresses << PAGE_SHIFT)
  91#define FIXADDR_START           (FIXADDR_TOP + PAGE_SIZE - __FIXADDR_SIZE)
  92#define FIXADDR_BOOT_START      (FIXADDR_TOP + PAGE_SIZE - __FIXADDR_BOOT_SIZE)
  93
  94extern void __this_fixmap_does_not_exist(void);
  95
  96/*
  97 * 'index to address' translation. If anyone tries to use the idx
  98 * directly without tranlation, we catch the bug with a NULL-deference
  99 * kernel oops. Illegal ranges of incoming indices are caught too.
 100 */
 101static __always_inline unsigned long fix_to_virt(const unsigned int idx)
 102{
 103        /*
 104         * this branch gets completely eliminated after inlining,
 105         * except when someone tries to use fixaddr indices in an
 106         * illegal way. (such as mixing up address types or using
 107         * out-of-range indices).
 108         *
 109         * If it doesn't get removed, the linker will complain
 110         * loudly with a reasonably clear error message..
 111         */
 112        if (idx >= __end_of_fixed_addresses)
 113                __this_fixmap_does_not_exist();
 114
 115        return __fix_to_virt(idx);
 116}
 117
 118static inline unsigned long virt_to_fix(const unsigned long vaddr)
 119{
 120        BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
 121        return __virt_to_fix(vaddr);
 122}
 123
 124#endif /* !__ASSEMBLY__ */
 125
 126#endif /* _ASM_TILE_FIXMAP_H */
 127