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);
+}