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#include <linux/mm_types.h>
  20
  21#define __fix_to_virt(x)        (FIXADDR_TOP - ((x) << PAGE_SHIFT))
  22#define __virt_to_fix(x)        ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
  23
  24#ifndef __ASSEMBLY__
  25/*
  26 * 'index to address' translation. If anyone tries to use the idx
  27 * directly without translation, we catch the bug with a NULL-deference
  28 * kernel oops. Illegal ranges of incoming indices are caught too.
  29 */
  30static __always_inline unsigned long fix_to_virt(const unsigned int idx)
  31{
  32        BUILD_BUG_ON(idx >= __end_of_fixed_addresses);
  33        return __fix_to_virt(idx);
  34}
  35
  36static inline unsigned long virt_to_fix(const unsigned long vaddr)
  37{
  38        BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
  39        return __virt_to_fix(vaddr);
  40}
  41
  42/*
  43 * Provide some reasonable defaults for page flags.
  44 * Not all architectures use all of these different types and some
  45 * architectures use different names.
  46 */
  47#ifndef FIXMAP_PAGE_NORMAL
  48#define FIXMAP_PAGE_NORMAL PAGE_KERNEL
  49#endif
  50#if !defined(FIXMAP_PAGE_RO) && defined(PAGE_KERNEL_RO)
  51#define FIXMAP_PAGE_RO PAGE_KERNEL_RO
  52#endif
  53#ifndef FIXMAP_PAGE_NOCACHE
  54#define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE
  55#endif
  56#ifndef FIXMAP_PAGE_IO
  57#define FIXMAP_PAGE_IO PAGE_KERNEL_IO
  58#endif
  59#ifndef FIXMAP_PAGE_CLEAR
  60#define FIXMAP_PAGE_CLEAR __pgprot(0)
  61#endif
  62
  63#ifndef set_fixmap
  64#define set_fixmap(idx, phys)                           \
  65        __set_fixmap(idx, phys, FIXMAP_PAGE_NORMAL)
  66#endif
  67
  68#ifndef clear_fixmap
  69#define clear_fixmap(idx)                       \
  70        __set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR)
  71#endif
  72
  73/* Return a pointer with offset calculated */
  74#define __set_fixmap_offset(idx, phys, flags)                           \
  75({                                                                      \
  76        unsigned long ________addr;                                     \
  77        __set_fixmap(idx, phys, flags);                                 \
  78        ________addr = fix_to_virt(idx) + ((phys) & (PAGE_SIZE - 1));   \
  79        ________addr;                                                   \
  80})
  81
  82#define set_fixmap_offset(idx, phys) \
  83        __set_fixmap_offset(idx, phys, FIXMAP_PAGE_NORMAL)
  84
  85/*
  86 * Some hardware wants to get fixmapped without caching.
  87 */
  88#define set_fixmap_nocache(idx, phys) \
  89        __set_fixmap(idx, phys, FIXMAP_PAGE_NOCACHE)
  90
  91#define set_fixmap_offset_nocache(idx, phys) \
  92        __set_fixmap_offset(idx, phys, FIXMAP_PAGE_NOCACHE)
  93
  94/*
  95 * Some fixmaps are for IO
  96 */
  97#define set_fixmap_io(idx, phys) \
  98        __set_fixmap(idx, phys, FIXMAP_PAGE_IO)
  99
 100#define set_fixmap_offset_io(idx, phys) \
 101        __set_fixmap_offset(idx, phys, FIXMAP_PAGE_IO)
 102
 103#endif /* __ASSEMBLY__ */
 104#endif /* __ASM_GENERIC_FIXMAP_H */
 105