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/*
* linux/arch/arm/mm/pgd.c
*
* Copyright (C) 1998-2005 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/mm.h>
#include <linux/gfp.h>
#include <linux/highmem.h>
#include <asm/pgalloc.h>
#include <asm/page.h>
#include <asm/tlbflush.h>
#include "mm.h"
DEFINE_SPINLOCK(pgd_lock);
LIST_HEAD(pgd_list);
static inline void pgd_list_add(pgd_t *pgd)
{
struct page *page = virt_to_page(pgd);
list_add(&page->lru, &pgd_list);
}
static inline void pgd_list_del(pgd_t *pgd)
{
struct page *page = virt_to_page(pgd);
list_del(&page->lru);
}
/*
* need to get a 16k page for level 1
*/
pgd_t *pgd_alloc(struct mm_struct *mm)
{
pgd_t *new_pgd, *init_pgd;
pud_t *new_pud, *init_pud;
pmd_t *new_pmd, *init_pmd;
pte_t *new_pte, *init_pte;
unsigned long flags;
new_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, 2);
if (!new_pgd)
goto no_pgd;
memset(new_pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
spin_lock_irqsave(&pgd_lock, flags);
/*
* Copy over the kernel and IO PGD entries
*/
init_pgd = pgd_offset_k(0);
memcpy(new_pgd + USER_PTRS_PER_PGD, init_pgd + USER_PTRS_PER_PGD,
(PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
#if !defined(CONFIG_CPU_CACHE_V7) || !defined(CONFIG_SMP)
clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
#endif
pgd_list_add(new_pgd);
spin_unlock_irqrestore(&pgd_lock, flags);
if (!vectors_high()) {
/*
* On ARM, first page must always be allocated since it
* contains the machine vectors.
*/
new_pud = pud_alloc(mm, new_pgd, 0);
if (!new_pud)
goto no_pud;
new_pmd = pmd_alloc(mm, new_pud, 0);
if (!new_pmd)
goto no_pmd;
new_pte = pte_alloc_map(mm, NULL, new_pmd, 0);
if (!new_pte)
goto no_pte;
init_pud = pud_offset(init_pgd, 0);
init_pmd = pmd_offset(init_pud, 0);
init_pte = pte_offset_map(init_pmd, 0);
set_pte_ext(new_pte, *init_pte, 0);
pte_unmap(init_pte);
pte_unmap(new_pte);
}
return new_pgd;
no_pte:
pmd_free(mm, new_pmd);
no_pmd:
pud_free(mm, new_pud);
no_pud:
spin_lock_irqsave(&pgd_lock, flags);
pgd_list_del(new_pgd);
spin_unlock_irqrestore(&pgd_lock, flags);
free_pages((unsigned long)new_pgd, 2);
no_pgd:
return NULL;
}
void pgd_free(struct mm_struct *mm, pgd_t *pgd_base)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pgtable_t pte;
unsigned long flags;
if (!pgd_base)
return;
spin_lock_irqsave(&pgd_lock, flags);
pgd_list_del(pgd_base);
spin_unlock_irqrestore(&pgd_lock, flags);
pgd = pgd_base + pgd_index(0);
if (pgd_none_or_clear_bad(pgd))
goto no_pgd;
pud = pud_offset(pgd, 0);
if (pud_none_or_clear_bad(pud))
goto no_pud;
pmd = pmd_offset(pud, 0);
if (pmd_none_or_clear_bad(pmd))
goto no_pmd;
pte = pmd_pgtable(*pmd);
pmd_clear(pmd);
pte_free(mm, pte);
no_pmd:
pud_clear(pud);
pmd_free(mm, pmd);
no_pud:
pgd_clear(pgd);
pud_free(mm, pud);
no_pgd:
free_pages((unsigned long) pgd_base, 2);
}
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