text: #ifndef _ASM_POWERPC_PGALLOC_64_H
  #define _ASM_POWERPC_PGALLOC_64_H
  /*
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version
   * 2 of the License, or (at your option) any later version.
   */
  
  #include <linux/slab.h>
  #include <linux/cpumask.h>
  #include <linux/percpu.h>
  
  struct vmemmap_backing {
  	struct vmemmap_backing *list;
  	unsigned long phys;
  	unsigned long virt_addr;
  };
  extern struct vmemmap_backing *vmemmap_list;
  
  /*
   * Functions that deal with pagetables that could be at any level of
   * the table need to be passed an "index_size" so they know how to
   * handle allocation.  For PTE pages (which are linked to a struct
   * page for now, and drawn from the main get_free_pages() pool), the
   * allocation size will be (2^index_size * sizeof(pointer)) and
   * allocations are drawn from the kmem_cache in PGT_CACHE(index_size).
   *
   * The maximum index size needs to be big enough to allow any
   * pagetable sizes we need, but small enough to fit in the low bits of
   * any page table pointer.  In other words all pagetables, even tiny
   * ones, must be aligned to allow at least enough low 0 bits to
   * contain this value.  This value is also used as a mask, so it must
   * be one less than a power of two.
   */
  #define MAX_PGTABLE_INDEX_SIZE	0xf
  
  extern struct kmem_cache *pgtable_cache[];
  #define PGT_CACHE(shift) pgtable_cache[shift]
  
  static inline pgd_t *pgd_alloc(struct mm_struct *mm)
  {
  	return kmem_cache_alloc(PGT_CACHE(PGD_INDEX_SIZE),
  			pgtable_gfp_flags(mm, GFP_KERNEL));
  }
  
  static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
  {
  	kmem_cache_free(PGT_CACHE(PGD_INDEX_SIZE), pgd);
  }
  
  #define pgd_populate(MM, PGD, PUD)	pgd_set(PGD, (unsigned long)PUD)
  
  static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
  {
  	return kmem_cache_alloc(PGT_CACHE(PUD_INDEX_SIZE),
  			pgtable_gfp_flags(mm, GFP_KERNEL));
  }
  
  static inline void pud_free(struct mm_struct *mm, pud_t *pud)
  {
  	kmem_cache_free(PGT_CACHE(PUD_INDEX_SIZE), pud);
  }
  
  static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
  {
  	pud_set(pud, (unsigned long)pmd);
  }
  
  static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
  				       pte_t *pte)
  {
  	pmd_set(pmd, (unsigned long)pte);
  }
  
  static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
  				pgtable_t pte_page)
  {
  	pmd_set(pmd, (unsigned long)page_address(pte_page));
  }
  
  #define pmd_pgtable(pmd) pmd_page(pmd)
  
  static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
  {
  	return kmem_cache_alloc(PGT_CACHE(PMD_CACHE_INDEX),
  			pgtable_gfp_flags(mm, GFP_KERNEL));
  }
  
  static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
  {
  	kmem_cache_free(PGT_CACHE(PMD_CACHE_INDEX), pmd);
  }
  
  
  static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
  {
  	return (pte_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
  }
  
  static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
  {
  	struct page *page;
  	pte_t *pte;
  
  	pte = (pte_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO | __GFP_ACCOUNT);
  	if (!pte)
  		return NULL;
  	page = virt_to_page(pte);
  	if (!pgtable_page_ctor(page)) {
  		__free_page(page);
  		return NULL;
  	}
  	return page;
  }
  
  static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
  {
  	free_page((unsigned long)pte);
  }
  
  static inline void pte_free(struct mm_struct *mm, pgtable_t ptepage)
  {
  	pgtable_page_dtor(ptepage);
  	__free_page(ptepage);
  }
  
  static inline void pgtable_free(void *table, int shift)
  {
  	if (!shift) {
  		pgtable_page_dtor(virt_to_page(table));
  		free_page((unsigned long)table);
  	} else {
  		BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE);
  		kmem_cache_free(PGT_CACHE(shift), table);
  	}
  }
  
  #define get_hugepd_cache_index(x)	(x)
  #ifdef CONFIG_SMP
  static inline void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift)
  {
  	unsigned long pgf = (unsigned long)table;
  
  	BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE);
  	pgf |= shift;
  	tlb_remove_table(tlb, (void *)pgf);
  }
  
  static inline void __tlb_remove_table(void *_table)
  {
  	void *table = (void *)((unsigned long)_table & ~MAX_PGTABLE_INDEX_SIZE);
  	unsigned shift = (unsigned long)_table & MAX_PGTABLE_INDEX_SIZE;
  
  	pgtable_free(table, shift);
  }
  
  #else
  static inline void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift)
  {
  	pgtable_free(table, shift);
  }
  #endif
  
  static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table,
  				  unsigned long address)
  {
  	tlb_flush_pgtable(tlb, address);
  	pgtable_free_tlb(tlb, page_address(table), 0);
  }
  
  #define __pmd_free_tlb(tlb, pmd, addr)		      \
  	pgtable_free_tlb(tlb, pmd, PMD_CACHE_INDEX)
  #ifndef CONFIG_PPC_64K_PAGES
  #define __pud_free_tlb(tlb, pud, addr)		      \
  	pgtable_free_tlb(tlb, pud, PUD_INDEX_SIZE)
  
  #endif /* CONFIG_PPC_64K_PAGES */
  
  #define check_pgt_cache()	do { } while (0)
  
  #endif /* _ASM_POWERPC_PGALLOC_64_H */
  