1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21/*
22 * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
23 */
24
25/*
26 * FMD Dynamic Reconfiguration (DR) Event Handling
27 *
28 * Fault manager scheme plug-ins must track characteristics of individual
29 * pieces of hardware.  As these components can be added or removed by a DR
30 * operation, we need to provide a means by which plug-ins can determine when
31 * they need to re-examine the current configuration.  We provide a simple
32 * mechanism whereby this task can be implemented using lazy evaluation: a
33 * simple 64-bit generation counter is maintained and incremented on *any* DR.
34 * Schemes can store the generation number in scheme-specific data structures,
35 * and then revalidate their contents if the current generation number has
36 * changed since the resource information was cached.  This method saves time,
37 * avoids the complexity of direct participation in DR, avoids the need for
38 * resource-specific processing of DR events, and is relatively easy to port
39 * to other systems that support dynamic reconfiguration.
40 *
41 * The dr generation is only incremented in response to hardware changes.  Since
42 * ASRUs can be in any scheme, including the device scheme, we must also be
43 * aware of software configuration changes which may affect the resource cache.
44 * In addition, we take a snapshot of the topology whenever a reconfiguration
45 * event occurs and notify any modules of the change.
46 */
47
48#include <sys/types.h>
49#include <sys/sunddi.h>
50#include <sys/sysevent/dr.h>
51#include <sys/sysevent/eventdefs.h>
52
53#include <stdio.h>
54#include <string.h>
55#include <unistd.h>
56#include <libsysevent.h>
57
58#undef MUTEX_HELD
59#undef RW_READ_HELD
60#undef RW_WRITE_HELD
61
62#include <fmd_asru.h>
63#include <fmd_error.h>
64#include <fmd_event.h>
65#include <fmd_fmri.h>
66#include <fmd_module.h>
67#include <fmd_subr.h>
68#include <fmd_topo.h>
69#include <fmd.h>
70
71void
72fmd_dr_event(sysevent_t *sep)
73{
74	uint64_t gen;
75	fmd_event_t *e;
76	const char *class = sysevent_get_class_name(sep);
77	const char *subclass = sysevent_get_subclass_name(sep);
78	hrtime_t evtime;
79	fmd_topo_t *ftp, *prev;
80
81	if (strcmp(class, EC_DR) == 0) {
82		if (strcmp(subclass, ESC_DR_AP_STATE_CHANGE) != 0 &&
83		    strcmp(subclass, ESC_DR_TARGET_STATE_CHANGE) != 0)
84			return;
85	/* LINTED: E_NOP_IF_STMT */
86	} else if (strcmp(class, EC_DEVFS) == 0) {
87		/*
88		 * A devfs configuration event can change the topology,
89		 * as disk nodes only exist when the device is configured.
90		 */
91	} else if (strcmp(class, EC_PLATFORM) == 0) {
92		/*
93		 * Since we rely on the SP to enumerate fans,
94		 * power-supplies and sensors/leds, it would be prudent
95		 * to take a new snapshot if the SP resets.
96		 */
97		if (strcmp(subclass, ESC_PLATFORM_SP_RESET) != 0)
98			return;
99	} else if (strcmp(class, EC_DEV_ADD) == 0 ||
100	    strcmp(class, EC_DEV_REMOVE) == 0) {
101		if (strcmp(subclass, ESC_DISK) != 0)
102			return;
103	} else
104		return;
105
106	/*
107	 * Take a topo snapshot and notify modules of the change.  Picking an
108	 * accurate time here is difficult.  On one hand, we have the timestamp
109	 * of the underlying sysevent, indicating when the reconfiguration event
110	 * occurred.  On the other hand, we are taking the topo snapshot
111	 * asynchronously, and hence the timestamp of the snapshot is the
112	 * current time.  Pretending this topo snapshot was valid at the time
113	 * the sysevent was posted seems wrong, so we instead opt for the
114	 * current time as an upper bound on the snapshot validity.
115	 *
116	 * Along these lines, we keep track of the last time we dispatched a
117	 * topo snapshot.  If the sysevent occurred before the last topo
118	 * snapshot, then don't bother dispatching another topo change event.
119	 * We've already indicated (to the best of our ability) the change in
120	 * topology.  This prevents endless topo snapshots in response to a
121	 * flurry of sysevents.
122	 */
123	sysevent_get_time(sep, &evtime);
124	prev = fmd_topo_hold();
125	if (evtime <= prev->ft_time_begin &&
126	    fmd.d_clockops == &fmd_timeops_native) {
127		fmd_topo_rele(prev);
128		return;
129	}
130	fmd_topo_rele(prev);
131
132	(void) pthread_mutex_lock(&fmd.d_stats_lock);
133	gen = fmd.d_stats->ds_dr_gen.fmds_value.ui64++;
134	(void) pthread_mutex_unlock(&fmd.d_stats_lock);
135
136	TRACE((FMD_DBG_XPRT, "dr event %p, gen=%llu", (void *)sep, gen));
137	fmd_topo_update();
138
139	ftp = fmd_topo_hold();
140	e = fmd_event_create(FMD_EVT_TOPO, ftp->ft_time_end, NULL, ftp);
141	fmd_modhash_dispatch(fmd.d_mod_hash, e);
142}
143