ia64/xen: implement the arch specific part of xencomm.

/*

 * 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

 */

#ifndef _ASM_IA64_XEN_XENCOMM_H

#define _ASM_IA64_XEN_XENCOMM_H

#include <xen/xencomm.h>

#include <asm/pgtable.h>

/* Must be called before any hypercall.  */

extern void xencomm_initialize(void);

/* Check if virtual contiguity means physical contiguity

 * where the passed address is a pointer value in virtual address.

 * On ia64, identity mapping area in region 7 or the piece of region 5

 * that is mapped by itr[IA64_TR_KERNEL]/dtr[IA64_TR_KERNEL]

 */

static inline int xencomm_is_phys_contiguous(unsigned long addr)

{

	return (PAGE_OFFSET <= addr &&

		addr < (PAGE_OFFSET + (1UL << IA64_MAX_PHYS_BITS))) ||

		(KERNEL_START <= addr &&

		 addr < KERNEL_START + KERNEL_TR_PAGE_SIZE);

}

#endif /* _ASM_IA64_XEN_XENCOMM_H */

# Makefile for Xen components

#

obj-y := hypercall.o

obj-y := hypercall.o xencomm.o

/*

 * 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);

}