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
  38 static inline void
  39 pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
  40 {
  41         pmd_set(pmd, pte);
  42 }
  43
  44 static inline void
  45 pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t ptep)
  46 {
  47         pmd_set(pmd, (pte_t *) ptep);
  48 }
  49
  50 static inline int __get_order_pgd(void)
  51 {
  52         return get_order(PTRS_PER_PGD * 4);
  53 }
  54
  55 static 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
  74 static 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
  88 static inline int __get_order_pte(void)
  89 {
  90         return get_order(PTRS_PER_PTE * 4);
  91 }
  92
  93 static 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_REPEAT | __GFP_ZERO,
  99                                          __get_order_pte());
 100
 101         return pte;
 102 }
 103
 104 static inline pgtable_t
 105 pte_alloc_one(struct mm_struct *mm, unsigned long address)
 106 {
 107         pgtable_t pte_pg;
 108         struct page *page;
 109
 110         pte_pg = __get_free_pages(GFP_KERNEL | __GFP_REPEAT, __get_order_pte());
 111         if (!pte_pg)
 112                 return 0;
 113         memzero((void *)pte_pg, PTRS_PER_PTE * 4);
 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
 123 static 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
 128 static inline void pte_free(struct mm_struct *mm, pgtable_t ptep)
 129 {
 130         pgtable_page_dtor(virt_to_page(ptep));
 131         free_pages(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) pmd_page_vaddr(pmd)
 138
 139 #endif /* _ASM_ARC_PGALLOC_H */