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#include <asm-generic/pgalloc.h>
  35
  36static inline void
  37pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
  38{
  39        /*
  40         * The cast to long below is OK in 32-bit PAE40 regime with long long pte
  41         * Despite "wider" pte, the pte table needs to be in non-PAE low memory
  42         * as all higher levels can only hold long pointers.
  43         *
  44         * The cast itself is needed given simplistic definition of set_pmd()
  45         */
  46        set_pmd(pmd, __pmd((unsigned long)pte));
  47}
  48
  49static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t pte_page)
  50{
  51        set_pmd(pmd, __pmd((unsigned long)page_address(pte_page)));
  52}
  53
  54static inline pgd_t *pgd_alloc(struct mm_struct *mm)
  55{
  56        pgd_t *ret = (pgd_t *) __get_free_page(GFP_KERNEL);
  57
  58        if (ret) {
  59                int num, num2;
  60                num = USER_PTRS_PER_PGD + USER_KERNEL_GUTTER / PGDIR_SIZE;
  61                memzero(ret, num * sizeof(pgd_t));
  62
  63                num2 = VMALLOC_SIZE / PGDIR_SIZE;
  64                memcpy(ret + num, swapper_pg_dir + num, num2 * sizeof(pgd_t));
  65
  66                memzero(ret + num + num2,
  67                               (PTRS_PER_PGD - num - num2) * sizeof(pgd_t));
  68
  69        }
  70        return ret;
  71}
  72
  73#if CONFIG_PGTABLE_LEVELS > 3
  74
  75static inline void p4d_populate(struct mm_struct *mm, p4d_t *p4dp, pud_t *pudp)
  76{
  77        set_p4d(p4dp, __p4d((unsigned long)pudp));
  78}
  79
  80#define __pud_free_tlb(tlb, pmd, addr)  pud_free((tlb)->mm, pmd)
  81
  82#endif
  83
  84#if CONFIG_PGTABLE_LEVELS > 2
  85
  86static inline void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmdp)
  87{
  88        set_pud(pudp, __pud((unsigned long)pmdp));
  89}
  90
  91#define __pmd_free_tlb(tlb, pmd, addr)  pmd_free((tlb)->mm, pmd)
  92
  93#endif
  94
  95#define __pte_free_tlb(tlb, pte, addr)  pte_free((tlb)->mm, pte)
  96
  97#endif /* _ASM_ARC_PGALLOC_H */
  98