1/*
  2 * Copyright (C) 2006 Hollis Blanchard <hollisb@us.ibm.com>, IBM Corporation
  3 *
  4 * This program is free software; you can redistribute it and/or modify
  5 * it under the terms of the GNU General Public License as published by
  6 * the Free Software Foundation; either version 2 of the License, or
  7 * (at your option) any later version.
  8 *
  9 * This program is distributed in the hope that it will be useful,
 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12 * GNU General Public License for more details.
 13 *
 14 * You should have received a copy of the GNU General Public License
 15 * along with this program; if not, write to the Free Software
 16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 17 */
 18
 19#include <linux/mm.h>
 20
 21static unsigned long kernel_virtual_offset;
 22static int is_xencomm_initialized;
 23
 24/* for xen early printk. It uses console io hypercall which uses xencomm.
 25 * However early printk may use it before xencomm initialization.
 26 */
 27int
 28xencomm_is_initialized(void)
 29{
 30	return is_xencomm_initialized;
 31}
 32
 33void
 34xencomm_initialize(void)
 35{
 36	kernel_virtual_offset = KERNEL_START - ia64_tpa(KERNEL_START);
 37	is_xencomm_initialized = 1;
 38}
 39
 40/* Translate virtual address to physical address.  */
 41unsigned long
 42xencomm_vtop(unsigned long vaddr)
 43{
 44	struct page *page;
 45	struct vm_area_struct *vma;
 46
 47	if (vaddr == 0)
 48		return 0UL;
 49
 50	if (REGION_NUMBER(vaddr) == 5) {
 51		pgd_t *pgd;
 52		pud_t *pud;
 53		pmd_t *pmd;
 54		pte_t *ptep;
 55
 56		/* On ia64, TASK_SIZE refers to current.  It is not initialized
 57		   during boot.
 58		   Furthermore the kernel is relocatable and __pa() doesn't
 59		   work on  addresses.  */
 60		if (vaddr >= KERNEL_START
 61		    && vaddr < (KERNEL_START + KERNEL_TR_PAGE_SIZE))
 62			return vaddr - kernel_virtual_offset;
 63
 64		/* In kernel area -- virtually mapped.  */
 65		pgd = pgd_offset_k(vaddr);
 66		if (pgd_none(*pgd) || pgd_bad(*pgd))
 67			return ~0UL;
 68
 69		pud = pud_offset(pgd, vaddr);
 70		if (pud_none(*pud) || pud_bad(*pud))
 71			return ~0UL;
 72
 73		pmd = pmd_offset(pud, vaddr);
 74		if (pmd_none(*pmd) || pmd_bad(*pmd))
 75			return ~0UL;
 76
 77		ptep = pte_offset_kernel(pmd, vaddr);
 78		if (!ptep)
 79			return ~0UL;
 80
 81		return (pte_val(*ptep) & _PFN_MASK) | (vaddr & ~PAGE_MASK);
 82	}
 83
 84	if (vaddr > TASK_SIZE) {
 85		/* percpu variables */
 86		if (REGION_NUMBER(vaddr) == 7 &&
 87		    REGION_OFFSET(vaddr) >= (1ULL << IA64_MAX_PHYS_BITS))
 88			ia64_tpa(vaddr);
 89
 90		/* kernel address */
 91		return __pa(vaddr);
 92	}
 93
 94	/* XXX double-check (lack of) locking */
 95	vma = find_extend_vma(current->mm, vaddr);
 96	if (!vma)
 97		return ~0UL;
 98
 99	/* We assume the page is modified.  */
100	page = follow_page(vma, vaddr, FOLL_WRITE | FOLL_TOUCH);
101	if (!page)
102		return ~0UL;
103
104	return (page_to_pfn(page) << PAGE_SHIFT) | (vaddr & ~PAGE_MASK);
105}