ARM: mm: HugeTLB support for LPAE systems.

[pandora-kernel.git] / arch / arm / mm / hugetlbpage.c

diff --git a/arch/arm/mm/hugetlbpage.c b/arch/arm/mm/hugetlbpage.c
new file mode 100644 (file)
index 0000000..93b78be
--- /dev/null
+++ b/arch/arm/mm/hugetlbpage.c
@@ -0,0 +1,100 @@
+/*
+ * 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 pmd_huge(pmd_t pmd)
+{
+       return (pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_SECT;
+}
+
+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;
+       unsigned long pfn;
+
+       pfn = ((pmd_val(*pmd) & HPAGE_MASK) >> PAGE_SHIFT);
+       page = pfn_to_page(pfn);
+       return page;
+}