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pgalloc.h

/*
 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
 * Copyright (C) 2008-2009 PetaLogix
 * Copyright (C) 2006 Atmark Techno, Inc.
 *
 * 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.
 */

#ifndef _ASM_MICROBLAZE_PGALLOC_H
#define _ASM_MICROBLAZE_PGALLOC_H

#ifdef CONFIG_MMU

#include <linux/kernel.h>     /* For min/max macros */
#include <linux/highmem.h>
#include <asm/setup.h>
#include <asm/io.h>
#include <asm/page.h>
#include <asm/cache.h>

#define PGDIR_ORDER     0

/*
 * This is handled very differently on MicroBlaze since out page tables
 * are all 0's and I want to be able to use these zero'd pages elsewhere
 * as well - it gives us quite a speedup.
 * -- Cort
 */
extern struct pgtable_cache_struct {
      unsigned long *pgd_cache;
      unsigned long *pte_cache;
      unsigned long pgtable_cache_sz;
} quicklists;

#define pgd_quicklist         (quicklists.pgd_cache)
#define pmd_quicklist         ((unsigned long *)0)
#define pte_quicklist         (quicklists.pte_cache)
#define pgtable_cache_size    (quicklists.pgtable_cache_sz)

extern unsigned long *zero_cache; /* head linked list of pre-zero'd pages */
extern atomic_t zero_sz; /* # currently pre-zero'd pages */
extern atomic_t zeropage_hits; /* # zero'd pages request that we've done */
extern atomic_t zeropage_calls; /* # zero'd pages request that've been made */
extern atomic_t zerototal; /* # pages zero'd over time */

#define zero_quicklist        (zero_cache)
#define zero_cache_sz         (zero_sz)
#define zero_cache_calls      (zeropage_calls)
#define zero_cache_hits       (zeropage_hits)
#define zero_cache_total      (zerototal)

/*
 * return a pre-zero'd page from the list,
 * return NULL if none available -- Cort
 */
extern unsigned long get_zero_page_fast(void);

extern void __bad_pte(pmd_t *pmd);

extern inline pgd_t *get_pgd_slow(void)
{
      pgd_t *ret;

      ret = (pgd_t *)__get_free_pages(GFP_KERNEL, PGDIR_ORDER);
      if (ret != NULL)
            clear_page(ret);
      return ret;
}

extern inline pgd_t *get_pgd_fast(void)
{
      unsigned long *ret;

      ret = pgd_quicklist;
      if (ret != NULL) {
            pgd_quicklist = (unsigned long *)(*ret);
            ret[0] = 0;
            pgtable_cache_size--;
      } else
            ret = (unsigned long *)get_pgd_slow();
      return (pgd_t *)ret;
}

extern inline void free_pgd_fast(pgd_t *pgd)
{
      *(unsigned long **)pgd = pgd_quicklist;
      pgd_quicklist = (unsigned long *) pgd;
      pgtable_cache_size++;
}

extern inline void free_pgd_slow(pgd_t *pgd)
{
      free_page((unsigned long)pgd);
}

#define pgd_free(mm, pgd)        free_pgd_fast(pgd)
#define pgd_alloc(mm)         get_pgd_fast()

#define pmd_pgtable(pmd)      pmd_page(pmd)

/*
 * We don't have any real pmd's, and this code never triggers because
 * the pgd will always be present..
 */
#define pmd_alloc_one_fast(mm, address)   ({ BUG(); ((pmd_t *)1); })
#define pmd_alloc_one(mm, address)  ({ BUG(); ((pmd_t *)2); })
/* FIXME two definition - look below */
#define pmd_free(mm, x)             do { } while (0)
#define pgd_populate(mm, pmd, pte)  BUG()

static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
            unsigned long address)
{
      pte_t *pte;
      extern int mem_init_done;
      extern void *early_get_page(void);
      if (mem_init_done) {
            pte = (pte_t *)__get_free_page(GFP_KERNEL |
                              __GFP_REPEAT | __GFP_ZERO);
      } else {
            pte = (pte_t *)early_get_page();
            if (pte)
                  clear_page(pte);
      }
      return pte;
}

static inline struct page *pte_alloc_one(struct mm_struct *mm,
            unsigned long address)
{
      struct page *ptepage;

#ifdef CONFIG_HIGHPTE
      int flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT;
#else
      int flags = GFP_KERNEL | __GFP_REPEAT;
#endif

      ptepage = alloc_pages(flags, 0);
      if (ptepage)
            clear_highpage(ptepage);
      return ptepage;
}

static inline pte_t *pte_alloc_one_fast(struct mm_struct *mm,
            unsigned long address)
{
      unsigned long *ret;

      ret = pte_quicklist;
      if (ret != NULL) {
            pte_quicklist = (unsigned long *)(*ret);
            ret[0] = 0;
            pgtable_cache_size--;
      }
      return (pte_t *)ret;
}

extern inline void pte_free_fast(pte_t *pte)
{
      *(unsigned long **)pte = pte_quicklist;
      pte_quicklist = (unsigned long *) pte;
      pgtable_cache_size++;
}

extern inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
{
      free_page((unsigned long)pte);
}

extern inline void pte_free_slow(struct page *ptepage)
{
      __free_page(ptepage);
}

extern inline void pte_free(struct mm_struct *mm, struct page *ptepage)
{
      __free_page(ptepage);
}

#define __pte_free_tlb(tlb, pte, addr)    pte_free((tlb)->mm, (pte))

#define pmd_populate(mm, pmd, pte)  (pmd_val(*(pmd)) = page_address(pte))

#define pmd_populate_kernel(mm, pmd, pte) \
            (pmd_val(*(pmd)) = (unsigned long) (pte))

/*
 * We don't have any real pmd's, and this code never triggers because
 * the pgd will always be present..
 */
#define pmd_alloc_one(mm, address)  ({ BUG(); ((pmd_t *)2); })
/*#define pmd_free(mm, x)                 do { } while (0)*/
#define __pmd_free_tlb(tlb, x, addr)      do { } while (0)
#define pgd_populate(mm, pmd, pte)  BUG()

extern int do_check_pgt_cache(int, int);

#endif /* CONFIG_MMU */

#define check_pgt_cache()     do {} while (0)

#endif /* _ASM_MICROBLAZE_PGALLOC_H */

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