xref: /freebsd-11-stable/sys/riscv/include/sf_buf.h

/*-
 * Copyright (c) 2003, 2005 Alan L. Cox <alc@cs.rice.edu>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD$
 */

#ifndef _MACHINE_SF_BUF_H_
#define	_MACHINE_SF_BUF_H_

/*
 * On this machine, the only purpose for which sf_buf is used is to implement
 * an opaque pointer required by the machine-independent parts of the kernel.
 * That pointer references the vm_page that is "mapped" by the sf_buf.  The
 * actual mapping is provided by the direct virtual-to-physical mapping.
 */
static inline vm_offset_t
sf_buf_kva(struct sf_buf *sf)
{

	return (PHYS_TO_DMAP(VM_PAGE_TO_PHYS((vm_page_t)sf)));
}

static inline vm_page_t
sf_buf_page(struct sf_buf *sf)
{

	return ((vm_page_t)sf);
}
#endif /* !_MACHINE_SF_BUF_H_ */