sun4v/os/wdt.c

/*
 * 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
 */
/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/types.h>
#include <sys/hsvc.h>
#include <sys/wdt.h>
#include <sys/cmn_err.h>
#include <sys/cyclic.h>
#include <sys/kmem.h>
#include <sys/systm.h>
#include <sys/sysmacros.h>
#include <sys/hypervisor_api.h>
#include <sys/mach_descrip.h>
#include <sys/mdesc.h>

#define WDT_ON          1
#define WDT_OFF         0

/*
 * MILLISEC defines the number of milliseconds in a second.
 */
#define WDT_DEFAULT_RESOLUTION  (1 * MILLISEC)  /* Default resolution = 1s */
#define WDT_MIN_TIMEOUT     (1 * MILLISEC)  /* Minimum timeout = 1s */
#define WDT_REGULAR_TIMEOUT (10 * MILLISEC) /* Default timeout = 10s */
#define WDT_LONG_TIMEOUT    (60 * MILLISEC) /* Long timeout = 60s */

#define WDT_MIN_COREAPI_MAJOR   1
#define WDT_MIN_COREAPI_MINOR   1

static void config_watchdog(uint64_t, int);
static void watchdog_cyclic_init(hrtime_t);

/*
 * Flag used to pat/suspend/resume the watchdog timer.
 */
int watchdog_activated = WDT_OFF;

/*
 * Tuneable to control watchdog functionality. Watchdog can be
 * disabled via /etc/system.
 */
int watchdog_enabled = 1;
static int watchdog_initialized = 0;

/*
 * The following tuneable can be set via /etc/system to control
 * watchdog pat frequency, which is set to approximately 44% of
 * the timeout value.
 */
static uint64_t watchdog_timeout = WDT_REGULAR_TIMEOUT;

static uint64_t watchdog_long_timeout = WDT_LONG_TIMEOUT;
static uint64_t watchdog_resolution = WDT_DEFAULT_RESOLUTION;

void
watchdog_init(void)
{
    int num_nodes;
    int nplat;
    md_t *mdp;
    mde_cookie_t *listp = NULL;
    int listsz;
    uint64_t major;
    uint64_t minor;
    uint64_t watchdog_max_timeout;
    hrtime_t cyclic_interval;

    if (!watchdog_enabled) {
        return;
    }

    if (hsvc_version(HSVC_GROUP_CORE, &major, &minor) != 0 ||
        major != WDT_MIN_COREAPI_MAJOR ||
        minor < WDT_MIN_COREAPI_MINOR) {
        cmn_err(CE_NOTE, "Disabling watchdog as watchdog services are "
            "not available\n");
        watchdog_enabled = 0;
        return;
    }

    /*
     * Get the watchdog-max-timeout and watchdog-resolution MD properties.
     */
    if ((mdp = md_get_handle()) == NULL) {
        cmn_err(CE_WARN, "Unable to initialize machine description, "
            "watchdog is disabled.");
        watchdog_enabled = 0;
        return;
    }

    num_nodes = md_node_count(mdp);
    ASSERT(num_nodes > 0);

    listsz = num_nodes * sizeof (mde_cookie_t);
    listp = kmem_zalloc(listsz, KM_SLEEP);

    nplat = md_scan_dag(mdp, md_root_node(mdp),
        md_find_name(mdp, "platform"), md_find_name(mdp, "fwd"), listp);

    ASSERT(nplat == 1);

    if (md_get_prop_val(mdp, listp[0], "watchdog-max-timeout",
        &watchdog_max_timeout) || watchdog_max_timeout < WDT_MIN_TIMEOUT) {
        cmn_err(CE_WARN, "Invalid watchdog-max-timeout, watchdog "
            "is disabled.");
        watchdog_enabled = 0;
        kmem_free(listp, listsz);
        (void) md_fini_handle(mdp);
        return;
    }

    /*
     * Make sure that watchdog timeout value is within limits.
     */
    if (watchdog_timeout < WDT_MIN_TIMEOUT)
        watchdog_timeout = WDT_MIN_TIMEOUT;
    else if (watchdog_timeout > WDT_LONG_TIMEOUT)
        watchdog_timeout = WDT_LONG_TIMEOUT;

    if (watchdog_timeout > watchdog_max_timeout)
        watchdog_timeout = watchdog_max_timeout;

    if (watchdog_long_timeout > watchdog_max_timeout)
        watchdog_long_timeout = watchdog_max_timeout;

    if (md_get_prop_val(mdp, listp[0], "watchdog-resolution",
        &watchdog_resolution)) {
        cmn_err(CE_WARN, "Cannot read watchdog-resolution, watchdog "
            "is disabled.");
        watchdog_enabled = 0;
        kmem_free(listp, listsz);
        (void) md_fini_handle(mdp);
        return;
    }

    if (watchdog_resolution == 0 ||
        watchdog_resolution > WDT_DEFAULT_RESOLUTION)
        watchdog_resolution = WDT_DEFAULT_RESOLUTION;

    kmem_free(listp, listsz);
    (void) md_fini_handle(mdp);

    /*
     * round the timeout to the nearest smaller value.
     */
    watchdog_long_timeout -=
        watchdog_long_timeout % watchdog_resolution;
    watchdog_timeout -=
        watchdog_timeout % watchdog_resolution;

    /*
     * Cyclic need to be fired twice the frequency of regular
     * watchdog timeout. Pedantic here and setting cyclic
     * frequency to approximately 44% of watchdog_timeout.
     */
    cyclic_interval = (watchdog_timeout >> 1) - (watchdog_timeout >> 4);
    /*
     * Note that regular timeout interval is in millisecond,
     * therefore to get cyclic interval in nanosecond need to
     * multiply by MICROSEC.
     */
    cyclic_interval *= MICROSEC;

    watchdog_cyclic_init(cyclic_interval);
    watchdog_initialized = 1;
    config_watchdog(watchdog_timeout, WDT_ON);
}

/*
 * Pat the watchdog timer periodically using the hypervisor API.
 * Regular pat occurs when the system runs normally.
 * Long pat is when system panics.
 */
void
watchdog_pat()
{
    if (watchdog_enabled && watchdog_activated) {
        if (panicstr)
            config_watchdog(watchdog_long_timeout, WDT_ON);
        else
            config_watchdog(watchdog_timeout, WDT_ON);
    }
}

/*
 * We don't save/restore the remaining watchdog timeout time at present.
 */
void
watchdog_suspend()
{
    if (watchdog_enabled && watchdog_activated) {
        config_watchdog(0, WDT_OFF);
    }
}

/*
 * We don't save/restore the remaining watchdog timeout time at present.
 */
void
watchdog_resume()
{
    if (watchdog_enabled && !watchdog_activated) {
        if (panicstr) {
            config_watchdog(watchdog_long_timeout, WDT_ON);
        } else {
            config_watchdog(watchdog_timeout, WDT_ON);
        }
    }
}

void
watchdog_clear()
{
    if (watchdog_enabled && watchdog_activated) {
        config_watchdog(0, WDT_OFF);
    }
}

static void
config_watchdog(uint64_t timeout, int new_state)
{
    uint64_t time_remaining;
    uint64_t ret;

    if (watchdog_initialized) {
        watchdog_activated = new_state;
        ret = hv_mach_set_watchdog(timeout, &time_remaining);
        if (ret != H_EOK) {
            cmn_err(CE_WARN, "Failed to operate on the watchdog. "
                "Error = 0x%lx", ret);
            watchdog_enabled = 0;
        }
    }
}

/*
 * Once the watchdog cyclic is initialized, it won't be removed.
 * The only way to not add the watchdog cyclic is to disable the watchdog
 * by setting the watchdog_enabled to 0 in /etc/system file.
 */
static void
watchdog_cyclic_init(hrtime_t wdt_cyclic_interval)
{
    cyc_handler_t hdlr;
    cyc_time_t when;

    hdlr.cyh_func = (cyc_func_t)watchdog_pat;
    hdlr.cyh_level = CY_HIGH_LEVEL;
    hdlr.cyh_arg = NULL;

    when.cyt_when = 0;
    when.cyt_interval = wdt_cyclic_interval;

    mutex_enter(&cpu_lock);
    (void) cyclic_add(&hdlr, &when);
    mutex_exit(&cpu_lock);
}