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  */
  29 static __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
  35 static 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 #ifndef FIXMAP_PAGE_NOCACHE
  50 #define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE
  51 #endif
  52 #ifndef FIXMAP_PAGE_IO
  53 #define FIXMAP_PAGE_IO PAGE_KERNEL_IO
  54 #endif
  55 #ifndef FIXMAP_PAGE_CLEAR
  56 #define FIXMAP_PAGE_CLEAR __pgprot(0)
  57 #endif
  58
  59 #ifndef set_fixmap
  60 #define set_fixmap(idx, phys)                           \
  61         __set_fixmap(idx, phys, FIXMAP_PAGE_NORMAL)
  62 #endif
  63
  64 #ifndef clear_fixmap
  65 #define clear_fixmap(idx)                       \
  66         __set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR)
  67 #endif
  68
  69 /* Return a pointer with offset calculated */
  70 #define __set_fixmap_offset(idx, phys, flags)                 \
  71 ({                                                            \
  72         unsigned long addr;                                   \
  73         __set_fixmap(idx, phys, flags);                       \
  74         addr = fix_to_virt(idx) + ((phys) & (PAGE_SIZE - 1)); \
  75         addr;                                                 \
  76 })
  77
  78 #define set_fixmap_offset(idx, phys) \
  79         __set_fixmap_offset(idx, phys, FIXMAP_PAGE_NORMAL)
  80
  81 /*
  82  * Some hardware wants to get fixmapped without caching.
  83  */
  84 #define set_fixmap_nocache(idx, phys) \
  85         __set_fixmap(idx, phys, FIXMAP_PAGE_NOCACHE)
  86
  87 #define set_fixmap_offset_nocache(idx, phys) \
  88         __set_fixmap_offset(idx, phys, FIXMAP_PAGE_NOCACHE)
  89
  90 /*
  91  * Some fixmaps are for IO
  92  */
  93 #define set_fixmap_io(idx, phys) \
  94         __set_fixmap(idx, phys, FIXMAP_PAGE_IO)
  95
  96 #endif /* __ASSEMBLY__ */
  97 #endif /* __ASM_GENERIC_FIXMAP_H */