LXR linux/include/asm-generic/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 * x86_32 and x86_64 integration by Gustavo F. Padovan, February 2009
  12 * Break out common bits to asm-generic by Mark Salter, November 2013
  13 */
  14
  15#ifndef __ASM_GENERIC_FIXMAP_H
  16#define __ASM_GENERIC_FIXMAP_H
  17
  18#include <linux/bug.h>
  19
  20#define __fix_to_virt(x)        (FIXADDR_TOP - ((x) << PAGE_SHIFT))
  21#define __virt_to_fix(x)        ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
  22
  23#ifndef __ASSEMBLY__
  24/*
  25 * 'index to address' translation. If anyone tries to use the idx
  26 * directly without translation, we catch the bug with a NULL-deference
  27 * kernel oops. Illegal ranges of incoming indices are caught too.
  28 */
  29static __always_inline unsigned long fix_to_virt(const unsigned int idx)
  30{
  31        BUILD_BUG_ON(idx >= __end_of_fixed_addresses);
  32        return __fix_to_virt(idx);
  33}
  34
  35static inline unsigned long virt_to_fix(const unsigned long vaddr)
  36{
  37        BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
  38        return __virt_to_fix(vaddr);
  39}
  40
  41/*
  42 * Provide some reasonable defaults for page flags.
  43 * Not all architectures use all of these different types and some
  44 * architectures use different names.
  45 */
  46#ifndef FIXMAP_PAGE_NORMAL
  47#define FIXMAP_PAGE_NORMAL PAGE_KERNEL
  48#endif
  49#if !defined(FIXMAP_PAGE_RO) && defined(PAGE_KERNEL_RO)
  50#define FIXMAP_PAGE_RO PAGE_KERNEL_RO
  51#endif
  52#ifndef FIXMAP_PAGE_NOCACHE
  53#define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE
  54#endif
  55#ifndef FIXMAP_PAGE_IO
  56#define FIXMAP_PAGE_IO PAGE_KERNEL_IO
  57#endif
  58#ifndef FIXMAP_PAGE_CLEAR
  59#define FIXMAP_PAGE_CLEAR __pgprot(0)
  60#endif
  61
  62#ifndef set_fixmap
  63#define set_fixmap(idx, phys)                           \
  64        __set_fixmap(idx, phys, FIXMAP_PAGE_NORMAL)
  65#endif
  66
  67#ifndef clear_fixmap
  68#define clear_fixmap(idx)                       \
  69        __set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR)
  70#endif
  71
  72/* Return a pointer with offset calculated */
  73#define __set_fixmap_offset(idx, phys, flags)                           \
  74({                                                                      \
  75        unsigned long ________addr;                                     \
  76        __set_fixmap(idx, phys, flags);                                 \
  77        ________addr = fix_to_virt(idx) + ((phys) & (PAGE_SIZE - 1));   \
  78        ________addr;                                                   \
  79})
  80
  81#define set_fixmap_offset(idx, phys) \
  82        __set_fixmap_offset(idx, phys, FIXMAP_PAGE_NORMAL)
  83
  84/*
  85 * Some hardware wants to get fixmapped without caching.
  86 */
  87#define set_fixmap_nocache(idx, phys) \
  88        __set_fixmap(idx, phys, FIXMAP_PAGE_NOCACHE)
  89
  90#define set_fixmap_offset_nocache(idx, phys) \
  91        __set_fixmap_offset(idx, phys, FIXMAP_PAGE_NOCACHE)
  92
  93/*
  94 * Some fixmaps are for IO
  95 */
  96#define set_fixmap_io(idx, phys) \
  97        __set_fixmap(idx, phys, FIXMAP_PAGE_IO)
  98
  99#define set_fixmap_offset_io(idx, phys) \
 100        __set_fixmap_offset(idx, phys, FIXMAP_PAGE_IO)
 101
 102#endif /* __ASSEMBLY__ */
 103#endif /* __ASM_GENERIC_FIXMAP_H */
 104