#ifndef _XEN_PAGE_H
  #define _XEN_PAGE_H

  #include <asm/page.h>
  
  /* The hypercall interface supports only 4KB page */
  #define XEN_PAGE_SHIFT	12
  #define XEN_PAGE_SIZE	(_AC(1, UL) << XEN_PAGE_SHIFT)
  #define XEN_PAGE_MASK	(~(XEN_PAGE_SIZE-1))
  #define xen_offset_in_page(p)	((unsigned long)(p) & ~XEN_PAGE_MASK)
  
  /*
   * We assume that PAGE_SIZE is a multiple of XEN_PAGE_SIZE
   * XXX: Add a BUILD_BUG_ON?
   */
  
  #define xen_pfn_to_page(xen_pfn)	\

  	(pfn_to_page((unsigned long)(xen_pfn) >> (PAGE_SHIFT - XEN_PAGE_SHIFT)))

  #define page_to_xen_pfn(page)		\

  	((page_to_pfn(page)) << (PAGE_SHIFT - XEN_PAGE_SHIFT))

  
  #define XEN_PFN_PER_PAGE	(PAGE_SIZE / XEN_PAGE_SIZE)
  
  #define XEN_PFN_DOWN(x)	((x) >> XEN_PAGE_SHIFT)
  #define XEN_PFN_UP(x)	(((x) + XEN_PAGE_SIZE-1) >> XEN_PAGE_SHIFT)
  #define XEN_PFN_PHYS(x)	((phys_addr_t)(x) << XEN_PAGE_SHIFT)

  #include <asm/xen/page.h>

  /* Return the GFN associated to the first 4KB of the page */

  static inline unsigned long xen_page_to_gfn(struct page *page)

  {

  	return pfn_to_gfn(page_to_xen_pfn(page));

  }

  struct xen_memory_region {

  	unsigned long start_pfn;
  	unsigned long n_pfns;

  };
  
  #define XEN_EXTRA_MEM_MAX_REGIONS 128 /* == E820MAX */
  
  extern __initdata
  struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS];

  extern unsigned long xen_released_pages;

  #endif	/* _XEN_PAGE_H */