mirror of https://gitee.com/openkylin/linux.git
100 lines
2.0 KiB
C
100 lines
2.0 KiB
C
/*
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* linux/arch/arm/mm/pgd.c
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*
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* Copyright (C) 1998-2005 Russell King
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/mm.h>
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#include <linux/gfp.h>
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#include <linux/highmem.h>
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#include <asm/pgalloc.h>
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#include <asm/page.h>
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#include <asm/tlbflush.h>
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#include "mm.h"
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/*
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* need to get a 16k page for level 1
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*/
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pgd_t *pgd_alloc(struct mm_struct *mm)
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{
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pgd_t *new_pgd, *init_pgd;
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pmd_t *new_pmd, *init_pmd;
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pte_t *new_pte, *init_pte;
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new_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, 2);
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if (!new_pgd)
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goto no_pgd;
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memset(new_pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
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/*
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* Copy over the kernel and IO PGD entries
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*/
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init_pgd = pgd_offset_k(0);
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memcpy(new_pgd + USER_PTRS_PER_PGD, init_pgd + USER_PTRS_PER_PGD,
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(PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
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clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
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if (!vectors_high()) {
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/*
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* On ARM, first page must always be allocated since it
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* contains the machine vectors.
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*/
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new_pmd = pmd_alloc(mm, new_pgd, 0);
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if (!new_pmd)
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goto no_pmd;
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new_pte = pte_alloc_map(mm, NULL, new_pmd, 0);
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if (!new_pte)
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goto no_pte;
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init_pmd = pmd_offset(init_pgd, 0);
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init_pte = pte_offset_map(init_pmd, 0);
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set_pte_ext(new_pte, *init_pte, 0);
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pte_unmap(init_pte);
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pte_unmap(new_pte);
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}
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return new_pgd;
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no_pte:
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pmd_free(mm, new_pmd);
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no_pmd:
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free_pages((unsigned long)new_pgd, 2);
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no_pgd:
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return NULL;
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}
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void pgd_free(struct mm_struct *mm, pgd_t *pgd_base)
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{
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pgd_t *pgd;
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pmd_t *pmd;
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pgtable_t pte;
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if (!pgd_base)
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return;
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pgd = pgd_base + pgd_index(0);
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if (pgd_none_or_clear_bad(pgd))
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goto no_pgd;
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pmd = pmd_offset(pgd, 0);
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if (pmd_none_or_clear_bad(pmd))
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goto no_pmd;
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pte = pmd_pgtable(*pmd);
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pmd_clear(pmd);
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pte_free(mm, pte);
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no_pmd:
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pgd_clear(pgd);
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pmd_free(mm, pmd);
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no_pgd:
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free_pages((unsigned long) pgd_base, 2);
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}
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