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authorCatalin Marinas <catalin.marinas@arm.com>2012-07-25 17:32:38 +0400
committerSteve Capper <steve.capper@linaro.org>2013-06-04 19:52:37 +0400
commit1355e2a6eb88f04d76125c057dc5fca64d4b6a9e (patch)
treeaf2c21aba209583f46e2424aec2e5d70b80c7965 /arch/arm/mm/hugetlbpage.c
parent0b19f93351dd68cb68a1a5b2d74e13d2ddfcfc64 (diff)
downloadlinux-1355e2a6eb88f04d76125c057dc5fca64d4b6a9e.tar.xz
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 <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>
Diffstat (limited to 'arch/arm/mm/hugetlbpage.c')
-rw-r--r--arch/arm/mm/hugetlbpage.c101
1 files changed, 101 insertions, 0 deletions
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 <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);
+}