text: #ifndef __ASM_SH_PGTABLE_2LEVEL_H
  #define __ASM_SH_PGTABLE_2LEVEL_H
  
  /*
   * traditional two-level paging structure:
   */
  
  #define PGDIR_SHIFT	22
  #define PTRS_PER_PGD	1024
  
  /*
   * this is two-level, so we don't really have any
   * PMD directory physically.
   */
  #define PMD_SHIFT	22
  #define PTRS_PER_PMD	1
  
  #define PTRS_PER_PTE	1024
  
  #ifndef __ASSEMBLY__
  #define pte_ERROR(e) \
  	printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e))
  #define pmd_ERROR(e) \
  	printk("%s:%d: bad pmd %08lx.\n", __FILE__, __LINE__, pmd_val(e))
  #define pgd_ERROR(e) \
  	printk("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
  
  /*
   * The "pgd_xxx()" functions here are trivial for a folded two-level
   * setup: the pgd is never bad, and a pmd always exists (as it's folded
   * into the pgd entry)
   */
  static inline int pgd_none(pgd_t pgd)		{ return 0; }
  static inline int pgd_bad(pgd_t pgd)		{ return 0; }
  static inline int pgd_present(pgd_t pgd)	{ return 1; }
  static inline void pgd_clear (pgd_t * pgdp) 	{ }
  
  /*
   * Certain architectures need to do special things when PTEs
   * within a page table are directly modified.  Thus, the following
   * hook is made available.
   */
  #define set_pte(pteptr, pteval) (*(pteptr) = pteval)
  /*
   * (pmds are folded into pgds so this doesn't get actually called,
   * but the define is needed for a generic inline function.)
   */
  #define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval)
  #define set_pgd(pgdptr, pgdval) (*(pgdptr) = pgdval)
  
  #define pgd_page(pgd) \
  ((unsigned long) __va(pgd_val(pgd) & PAGE_MASK))
  
  static inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
  {
  	return (pmd_t *) dir;
  }
  
  #define pte_pfn(x)		((unsigned long)(((x).pte >> PAGE_SHIFT)))
  #define pfn_pte(pfn, prot)	__pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
  #define pfn_pmd(pfn, prot)	__pmd(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
  
  #endif /* !__ASSEMBLY__ */
  
  #endif /* __ASM_SH_PGTABLE_2LEVEL_H */
  