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

   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 *       deal with struct page. That 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
  35static inline void
  36pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
  37{
  38        pmd_set(pmd, pte);
  39}
  40
  41static inline void
  42pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t ptep)
  43{
  44        pmd_set(pmd, (pte_t *) ptep);
  45}
  46
  47static inline int __get_order_pgd(void)
  48{
  49        return get_order(PTRS_PER_PGD * sizeof(pgd_t));
  50}
  51
  52static 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
  71static 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
  85static inline int __get_order_pte(void)
  86{
  87        return get_order(PTRS_PER_PTE * sizeof(pte_t));
  88}
  89
  90static 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
 100static inline pgtable_t
 101pte_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
 119static 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
 124static 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#endif /* _ASM_ARC_PGALLOC_H */
 133