LXR linux/arch/arc/include/asm/pgalloc.h

   1/*
   2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation.
   7 *
   8 * vineetg: June 2011
   9 *  -"/proc/meminfo | grep PageTables" kept on increasing
  10 *   Recently added pgtable dtor was not getting called.
  11 *
  12 * vineetg: May 2011
  13 *  -Variable pg-sz means that Page Tables could be variable sized themselves
  14 *    So calculate it based on addr traversal split [pgd-bits:pte-bits:xxx]
  15 *  -Page Table size capped to max 1 to save memory - hence verified.
  16 *  -Since these deal with constants, gcc compile-time optimizes them.
  17 *
  18 * vineetg: Nov 2010
  19 *  -Added pgtable ctor/dtor used for pgtable mem accounting
  20 *
  21 * vineetg: April 2010
  22 *  -Switched pgtable_t from being struct page * to unsigned long
  23 *      =Needed so that Page Table allocator (pte_alloc_one) is not forced to
  24 *       to deal with struct page. Thay way in future we can make it allocate
  25 *       multiple PG Tbls in one Page Frame
  26 *      =sweet side effect is avoiding calls to ugly page_address( ) from the
  27 *       pg-tlb allocator sub-sys (pte_alloc_one, ptr_free, pmd_populate
  28 *
  29 *  Amit Bhor, Sameer Dhavale: Codito Technologies 2004
  30 */
  31
  32#ifndef _ASM_ARC_PGALLOC_H
  33#define _ASM_ARC_PGALLOC_H
  34
  35#include <linux/mm.h>
  36#include <linux/log2.h>
  37
  38static inline void
  39pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
  40{
  41        pmd_set(pmd, pte);
  42}
  43
  44static inline void
  45pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t ptep)
  46{
  47        pmd_set(pmd, (pte_t *) ptep);
  48}
  49
  50static inline int __get_order_pgd(void)
  51{
  52        return get_order(PTRS_PER_PGD * sizeof(pgd_t));
  53}
  54
  55static inline pgd_t *pgd_alloc(struct mm_struct *mm)
  56{
  57        int num, num2;
  58        pgd_t *ret = (pgd_t *) __get_free_pages(GFP_KERNEL, __get_order_pgd());
  59
  60        if (ret) {
  61                num = USER_PTRS_PER_PGD + USER_KERNEL_GUTTER / PGDIR_SIZE;
  62                memzero(ret, num * sizeof(pgd_t));
  63
  64                num2 = VMALLOC_SIZE / PGDIR_SIZE;
  65                memcpy(ret + num, swapper_pg_dir + num, num2 * sizeof(pgd_t));
  66
  67                memzero(ret + num + num2,
  68                               (PTRS_PER_PGD - num - num2) * sizeof(pgd_t));
  69
  70        }
  71        return ret;
  72}
  73
  74static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
  75{
  76        free_pages((unsigned long)pgd, __get_order_pgd());
  77}
  78
  79
  80/*
  81 * With software-only page-tables, addr-split for traversal is tweakable and
  82 * that directly governs how big tables would be at each level.
  83 * Further, the MMU page size is configurable.
  84 * Thus we need to programatically assert the size constraint
  85 * All of this is const math, allowing gcc to do constant folding/propagation.
  86 */
  87
  88static inline int __get_order_pte(void)
  89{
  90        return get_order(PTRS_PER_PTE * sizeof(pte_t));
  91}
  92
  93static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
  94                                        unsigned long address)
  95{
  96        pte_t *pte;
  97
  98        pte = (pte_t *) __get_free_pages(GFP_KERNEL | __GFP_ZERO,
  99                                         __get_order_pte());
 100
 101        return pte;
 102}
 103
 104static inline pgtable_t
 105pte_alloc_one(struct mm_struct *mm, unsigned long address)
 106{
 107        pgtable_t pte_pg;
 108        struct page *page;
 109
 110        pte_pg = (pgtable_t)__get_free_pages(GFP_KERNEL, __get_order_pte());
 111        if (!pte_pg)
 112                return 0;
 113        memzero((void *)pte_pg, PTRS_PER_PTE * sizeof(pte_t));
 114        page = virt_to_page(pte_pg);
 115        if (!pgtable_page_ctor(page)) {
 116                __free_page(page);
 117                return 0;
 118        }
 119
 120        return pte_pg;
 121}
 122
 123static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 124{
 125        free_pages((unsigned long)pte, __get_order_pte()); /* takes phy addr */
 126}
 127
 128static inline void pte_free(struct mm_struct *mm, pgtable_t ptep)
 129{
 130        pgtable_page_dtor(virt_to_page(ptep));
 131        free_pages((unsigned long)ptep, __get_order_pte());
 132}
 133
 134#define __pte_free_tlb(tlb, pte, addr)  pte_free((tlb)->mm, pte)
 135
 136#define check_pgt_cache()   do { } while (0)
 137#define pmd_pgtable(pmd)        ((pgtable_t) pmd_page_vaddr(pmd))
 138
 139#endif /* _ASM_ARC_PGALLOC_H */
 140