1355e2a6eb
This patch adds support for hugetlbfs based on the x86 implementation. It allows mapping of 2MB sections (see Documentation/vm/hugetlbpage.txt for usage). The 64K pages configuration is not supported (section size is 512MB in this case). Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> [steve.capper@linaro.org: symbolic constants replace numbers in places. Split up into multiple files, to simplify future non-LPAE support, removed huge_pmd_share code, as this is very rarely executed, Added PROT_NONE support]. Signed-off-by: Steve Capper <steve.capper@linaro.org> Reviewed-by: Will Deacon <will.deacon@arm.com>
102 lines
2.3 KiB
C
102 lines
2.3 KiB
C
/*
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* arch/arm/mm/hugetlbpage.c
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*
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* Copyright (C) 2012 ARM Ltd.
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*
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* Based on arch/x86/include/asm/hugetlb.h and Bill Carson's patches
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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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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <linux/pagemap.h>
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#include <linux/err.h>
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#include <linux/sysctl.h>
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#include <asm/mman.h>
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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#include <asm/pgalloc.h>
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/*
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* On ARM, huge pages are backed by pmd's rather than pte's, so we do a lot
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* of type casting from pmd_t * to pte_t *.
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*/
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pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd = NULL;
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pgd = pgd_offset(mm, addr);
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if (pgd_present(*pgd)) {
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pud = pud_offset(pgd, addr);
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if (pud_present(*pud))
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pmd = pmd_offset(pud, addr);
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}
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return (pte_t *)pmd;
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}
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struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
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int write)
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{
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return ERR_PTR(-EINVAL);
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}
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int pud_huge(pud_t pud)
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{
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return 0;
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}
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int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
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{
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return 0;
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}
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pte_t *huge_pte_alloc(struct mm_struct *mm,
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unsigned long addr, unsigned long sz)
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{
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pgd_t *pgd;
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pud_t *pud;
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pte_t *pte = NULL;
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pgd = pgd_offset(mm, addr);
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pud = pud_alloc(mm, pgd, addr);
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if (pud)
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pte = (pte_t *)pmd_alloc(mm, pud, addr);
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return pte;
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}
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struct page *
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follow_huge_pmd(struct mm_struct *mm, unsigned long address,
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pmd_t *pmd, int write)
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{
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struct page *page;
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page = pte_page(*(pte_t *)pmd);
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if (page)
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page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
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return page;
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}
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int pmd_huge(pmd_t pmd)
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{
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return pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT);
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}
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