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include/asm-generic/fixmap.h 2.84 KB
81f7e3824   Eric Lee   Initial Release, ...
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  /*
   * fixmap.h: compile-time virtual memory allocation
   *
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   *
   * Copyright (C) 1998 Ingo Molnar
   *
   * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
   * x86_32 and x86_64 integration by Gustavo F. Padovan, February 2009
   * Break out common bits to asm-generic by Mark Salter, November 2013
   */
  
  #ifndef __ASM_GENERIC_FIXMAP_H
  #define __ASM_GENERIC_FIXMAP_H
  
  #include <linux/bug.h>
  
  #define __fix_to_virt(x)	(FIXADDR_TOP - ((x) << PAGE_SHIFT))
  #define __virt_to_fix(x)	((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
  
  #ifndef __ASSEMBLY__
  /*
   * 'index to address' translation. If anyone tries to use the idx
   * directly without translation, we catch the bug with a NULL-deference
   * kernel oops. Illegal ranges of incoming indices are caught too.
   */
  static __always_inline unsigned long fix_to_virt(const unsigned int idx)
  {
  	BUILD_BUG_ON(idx >= __end_of_fixed_addresses);
  	return __fix_to_virt(idx);
  }
  
  static inline unsigned long virt_to_fix(const unsigned long vaddr)
  {
  	BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
  	return __virt_to_fix(vaddr);
  }
  
  /*
   * Provide some reasonable defaults for page flags.
   * Not all architectures use all of these different types and some
   * architectures use different names.
   */
  #ifndef FIXMAP_PAGE_NORMAL
  #define FIXMAP_PAGE_NORMAL PAGE_KERNEL
  #endif
  #if !defined(FIXMAP_PAGE_RO) && defined(PAGE_KERNEL_RO)
  #define FIXMAP_PAGE_RO PAGE_KERNEL_RO
  #endif
  #ifndef FIXMAP_PAGE_NOCACHE
  #define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE
  #endif
  #ifndef FIXMAP_PAGE_IO
  #define FIXMAP_PAGE_IO PAGE_KERNEL_IO
  #endif
  #ifndef FIXMAP_PAGE_CLEAR
  #define FIXMAP_PAGE_CLEAR __pgprot(0)
  #endif
  
  #ifndef set_fixmap
  #define set_fixmap(idx, phys)				\
  	__set_fixmap(idx, phys, FIXMAP_PAGE_NORMAL)
  #endif
  
  #ifndef clear_fixmap
  #define clear_fixmap(idx)			\
  	__set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR)
  #endif
  
  /* Return a pointer with offset calculated */
  #define __set_fixmap_offset(idx, phys, flags)				\
  ({									\
  	unsigned long ________addr;					\
  	__set_fixmap(idx, phys, flags);					\
  	________addr = fix_to_virt(idx) + ((phys) & (PAGE_SIZE - 1));	\
  	________addr;							\
  })
  
  #define set_fixmap_offset(idx, phys) \
  	__set_fixmap_offset(idx, phys, FIXMAP_PAGE_NORMAL)
  
  /*
   * Some hardware wants to get fixmapped without caching.
   */
  #define set_fixmap_nocache(idx, phys) \
  	__set_fixmap(idx, phys, FIXMAP_PAGE_NOCACHE)
  
  #define set_fixmap_offset_nocache(idx, phys) \
  	__set_fixmap_offset(idx, phys, FIXMAP_PAGE_NOCACHE)
  
  /*
   * Some fixmaps are for IO
   */
  #define set_fixmap_io(idx, phys) \
  	__set_fixmap(idx, phys, FIXMAP_PAGE_IO)
  
  #define set_fixmap_offset_io(idx, phys) \
  	__set_fixmap_offset(idx, phys, FIXMAP_PAGE_IO)
  
  #endif /* __ASSEMBLY__ */
  #endif /* __ASM_GENERIC_FIXMAP_H */