From 1355e2a6eb88f04d76125c057dc5fca64d4b6a9e Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Wed, 25 Jul 2012 14:32:38 +0100 Subject: ARM: mm: HugeTLB support for LPAE systems. 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 [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 Reviewed-by: Will Deacon --- arch/arm/mm/hugetlbpage.c | 101 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 101 insertions(+) create mode 100644 arch/arm/mm/hugetlbpage.c (limited to 'arch/arm/mm/hugetlbpage.c') diff --git a/arch/arm/mm/hugetlbpage.c b/arch/arm/mm/hugetlbpage.c new file mode 100644 index 000000000000..3d1e4a205b0b --- /dev/null +++ b/arch/arm/mm/hugetlbpage.c @@ -0,0 +1,101 @@ +/* + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * 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); +} -- cgit v1.2.3