/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 * $FreeBSD$
 */

/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

void
dtrace_vtime_enable(void)
{
	dtrace_vtime_state_t state, nstate = 0;

	do {
		state = dtrace_vtime_active;

		switch (state) {
		case DTRACE_VTIME_INACTIVE:
			nstate = DTRACE_VTIME_ACTIVE;
			break;

		case DTRACE_VTIME_INACTIVE_TNF:
			nstate = DTRACE_VTIME_ACTIVE_TNF;
			break;

		case DTRACE_VTIME_ACTIVE:
		case DTRACE_VTIME_ACTIVE_TNF:
			panic("DTrace virtual time already enabled");
			/*NOTREACHED*/
		}

	} while	(dtrace_cas32((uint32_t *)&dtrace_vtime_active,
	    state, nstate) != state);
}

void
dtrace_vtime_disable(void)
{
	dtrace_vtime_state_t state, nstate = 0;

	do {
		state = dtrace_vtime_active;

		switch (state) {
		case DTRACE_VTIME_ACTIVE:
			nstate = DTRACE_VTIME_INACTIVE;
			break;

		case DTRACE_VTIME_ACTIVE_TNF:
			nstate = DTRACE_VTIME_INACTIVE_TNF;
			break;

		case DTRACE_VTIME_INACTIVE:
		case DTRACE_VTIME_INACTIVE_TNF:
			panic("DTrace virtual time already disabled");
			/*NOTREACHED*/
		}

	} while	(dtrace_cas32((uint32_t *)&dtrace_vtime_active,
	    state, nstate) != state);
}

void
dtrace_vtime_switch(kthread_t *next)
{
	dtrace_icookie_t cookie;
	hrtime_t ts;

	cookie = dtrace_interrupt_disable();
	ts = dtrace_gethrtime();

	if (curthread->t_dtrace_start != 0) {
		curthread->t_dtrace_vtime += ts - curthread->t_dtrace_start;
		curthread->t_dtrace_start = 0;
	}

	if (next != NULL)
		next->t_dtrace_start = ts;

	dtrace_interrupt_enable(cookie);
}