1 files changed, 94 insertions, 0 deletions
diff --git a/arch/ia64/xen/xencomm.c b/arch/ia64/xen/xencomm.c
new file mode 100644
index 000000000000..3dc307f0a40d
--- /dev/null
+++ b/arch/ia64/xen/xencomm.c
@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2006 Hollis Blanchard <hollisb@us.ibm.com>, IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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/mm.h>
+
+static unsigned long kernel_virtual_offset;
+
+void
+xencomm_initialize(void)
+{
+	kernel_virtual_offset = KERNEL_START - ia64_tpa(KERNEL_START);
+}
+
+/* Translate virtual address to physical address.  */
+unsigned long
+xencomm_vtop(unsigned long vaddr)
+{
+	struct page *page;
+	struct vm_area_struct *vma;
+
+	if (vaddr == 0)
+		return 0UL;
+
+	if (REGION_NUMBER(vaddr) == 5) {
+		pgd_t *pgd;
+		pud_t *pud;
+		pmd_t *pmd;
+		pte_t *ptep;
+
+		/* On ia64, TASK_SIZE refers to current.  It is not initialized
+		   during boot.
+		   Furthermore the kernel is relocatable and __pa() doesn't
+		   work on  addresses.  */
+		if (vaddr >= KERNEL_START
+		    && vaddr < (KERNEL_START + KERNEL_TR_PAGE_SIZE))
+			return vaddr - kernel_virtual_offset;
+
+		/* In kernel area -- virtually mapped.  */
+		pgd = pgd_offset_k(vaddr);
+		if (pgd_none(*pgd) || pgd_bad(*pgd))
+			return ~0UL;
+
+		pud = pud_offset(pgd, vaddr);
+		if (pud_none(*pud) || pud_bad(*pud))
+			return ~0UL;
+
+		pmd = pmd_offset(pud, vaddr);
+		if (pmd_none(*pmd) || pmd_bad(*pmd))
+			return ~0UL;
+
+		ptep = pte_offset_kernel(pmd, vaddr);
+		if (!ptep)
+			return ~0UL;
+
+		return (pte_val(*ptep) & _PFN_MASK) | (vaddr & ~PAGE_MASK);
+	}
+
+	if (vaddr > TASK_SIZE) {
+		/* percpu variables */
+		if (REGION_NUMBER(vaddr) == 7 &&
+		    REGION_OFFSET(vaddr) >= (1ULL << IA64_MAX_PHYS_BITS))
+			ia64_tpa(vaddr);
+
+		/* kernel address */
+		return __pa(vaddr);
+	}
+
+	/* XXX double-check (lack of) locking */
+	vma = find_extend_vma(current->mm, vaddr);
+	if (!vma)
+		return ~0UL;
+
+	/* We assume the page is modified.  */
+	page = follow_page(vma, vaddr, FOLL_WRITE | FOLL_TOUCH);
+	if (!page)
+		return ~0UL;
+
+	return (page_to_pfn(page) << PAGE_SHIFT) | (vaddr & ~PAGE_MASK);
+}