root/arch/arc/include/asm/pgalloc.h

INCLUDED FROM

DEFINITIONS

1. pmd_populate_kernel
2. pmd_populate
3. __get_order_pgd
4. pgd_alloc
5. pgd_free
6. __get_order_pte
7. pte_alloc_one_kernel
8. pte_alloc_one
9. pte_free_kernel
10. pte_free

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   4  *
   5  * vineetg: June 2011
   6  *  -"/proc/meminfo | grep PageTables" kept on increasing
   7  *   Recently added pgtable dtor was not getting called.
   8  *
   9  * vineetg: May 2011
  10  *  -Variable pg-sz means that Page Tables could be variable sized themselves
  11  *    So calculate it based on addr traversal split [pgd-bits:pte-bits:xxx]
  12  *  -Page Table size capped to max 1 to save memory - hence verified.
  13  *  -Since these deal with constants, gcc compile-time optimizes them.
  14  *
  15  * vineetg: Nov 2010
  16  *  -Added pgtable ctor/dtor used for pgtable mem accounting
  17  *
  18  * vineetg: April 2010
  19  *  -Switched pgtable_t from being struct page * to unsigned long
  20  *      =Needed so that Page Table allocator (pte_alloc_one) is not forced to
  21  *       to deal with struct page. Thay way in future we can make it allocate
  22  *       multiple PG Tbls in one Page Frame
  23  *      =sweet side effect is avoiding calls to ugly page_address( ) from the
  24  *       pg-tlb allocator sub-sys (pte_alloc_one, ptr_free, pmd_populate
  25  *
  26  *  Amit Bhor, Sameer Dhavale: Codito Technologies 2004
  27  */
  28 
  29 #ifndef _ASM_ARC_PGALLOC_H
  30 #define _ASM_ARC_PGALLOC_H
  31 
  32 #include <linux/mm.h>
  33 #include <linux/log2.h>
  34 
  35 static inline void
  36 pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
  37 {
  38         pmd_set(pmd, pte);
  39 }
  40 
  41 static inline void
  42 pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t ptep)
  43 {
  44         pmd_set(pmd, (pte_t *) ptep);
  45 }
  46 
  47 static inline int __get_order_pgd(void)
  48 {
  49         return get_order(PTRS_PER_PGD * sizeof(pgd_t));
  50 }
  51 
  52 static inline pgd_t *pgd_alloc(struct mm_struct *mm)
  53 {
  54         int num, num2;
  55         pgd_t *ret = (pgd_t *) __get_free_pages(GFP_KERNEL, __get_order_pgd());
  56 
  57         if (ret) {
  58                 num = USER_PTRS_PER_PGD + USER_KERNEL_GUTTER / PGDIR_SIZE;
  59                 memzero(ret, num * sizeof(pgd_t));
  60 
  61                 num2 = VMALLOC_SIZE / PGDIR_SIZE;
  62                 memcpy(ret + num, swapper_pg_dir + num, num2 * sizeof(pgd_t));
  63 
  64                 memzero(ret + num + num2,
  65                                (PTRS_PER_PGD - num - num2) * sizeof(pgd_t));
  66 
  67         }
  68         return ret;
  69 }
  70 
  71 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
  72 {
  73         free_pages((unsigned long)pgd, __get_order_pgd());
  74 }
  75 
  76 
  77 /*
  78  * With software-only page-tables, addr-split for traversal is tweakable and
  79  * that directly governs how big tables would be at each level.
  80  * Further, the MMU page size is configurable.
  81  * Thus we need to programatically assert the size constraint
  82  * All of this is const math, allowing gcc to do constant folding/propagation.
  83  */
  84 
  85 static inline int __get_order_pte(void)
  86 {
  87         return get_order(PTRS_PER_PTE * sizeof(pte_t));
  88 }
  89 
  90 static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
  91 {
  92         pte_t *pte;
  93 
  94         pte = (pte_t *) __get_free_pages(GFP_KERNEL | __GFP_ZERO,
  95                                          __get_order_pte());
  96 
  97         return pte;
  98 }
  99 
 100 static inline pgtable_t
 101 pte_alloc_one(struct mm_struct *mm)
 102 {
 103         pgtable_t pte_pg;
 104         struct page *page;
 105 
 106         pte_pg = (pgtable_t)__get_free_pages(GFP_KERNEL, __get_order_pte());
 107         if (!pte_pg)
 108                 return 0;
 109         memzero((void *)pte_pg, PTRS_PER_PTE * sizeof(pte_t));
 110         page = virt_to_page(pte_pg);
 111         if (!pgtable_pte_page_ctor(page)) {
 112                 __free_page(page);
 113                 return 0;
 114         }
 115 
 116         return pte_pg;
 117 }
 118 
 119 static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 120 {
 121         free_pages((unsigned long)pte, __get_order_pte()); /* takes phy addr */
 122 }
 123 
 124 static inline void pte_free(struct mm_struct *mm, pgtable_t ptep)
 125 {
 126         pgtable_pte_page_dtor(virt_to_page(ptep));
 127         free_pages((unsigned long)ptep, __get_order_pte());
 128 }
 129 
 130 #define __pte_free_tlb(tlb, pte, addr)  pte_free((tlb)->mm, pte)
 131 
 132 #define pmd_pgtable(pmd)        ((pgtable_t) pmd_page_vaddr(pmd))
 133 
 134 #endif /* _ASM_ARC_PGALLOC_H */