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- /*
- * arch/arm/mm/hugetlbpage.c
- *
- * Copyright (C) 2012 ARM Ltd.
- *
- * Based on arch/x86/include/asm/hugetlb.h and Bill Carson's patches
- *
- * 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.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- */
- #include <linux/init.h>
- #include <linux/fs.h>
- #include <linux/mm.h>
- #include <linux/hugetlb.h>
- #include <linux/pagemap.h>
- #include <linux/err.h>
- #include <linux/sysctl.h>
- #include <asm/mman.h>
- #include <asm/tlb.h>
- #include <asm/tlbflush.h>
- #include <asm/pgalloc.h>
- /*
- * On ARM, huge pages are backed by pmd's rather than pte's, so we do a lot
- * of type casting from pmd_t * to pte_t *.
- */
- pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
- {
- pgd_t *pgd;
- pud_t *pud;
- pmd_t *pmd = NULL;
- pgd = pgd_offset(mm, addr);
- if (pgd_present(*pgd)) {
- pud = pud_offset(pgd, addr);
- if (pud_present(*pud))
- pmd = pmd_offset(pud, addr);
- }
- return (pte_t *)pmd;
- }
- struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
- int write)
- {
- return ERR_PTR(-EINVAL);
- }
- int pud_huge(pud_t pud)
- {
- return 0;
- }
- int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
- {
- return 0;
- }
- pte_t *huge_pte_alloc(struct mm_struct *mm,
- unsigned long addr, unsigned long sz)
- {
- pgd_t *pgd;
- pud_t *pud;
- pte_t *pte = NULL;
- pgd = pgd_offset(mm, addr);
- pud = pud_alloc(mm, pgd, addr);
- if (pud)
- pte = (pte_t *)pmd_alloc(mm, pud, addr);
- return pte;
- }
- struct page *
- follow_huge_pmd(struct mm_struct *mm, unsigned long address,
- pmd_t *pmd, int write)
- {
- struct page *page;
- page = pte_page(*(pte_t *)pmd);
- if (page)
- page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
- return page;
- }
- int pmd_huge(pmd_t pmd)
- {
- return pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT);
- }
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