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  */
  30 static __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
  36 static 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 */