xref: /titanic_41/usr/src/cmd/fm/fmd/common/fmd_dr.c (revision fa9e4066f08beec538e775443c5be79dd423fcab)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*
30  * FMD Dynamic Reconfiguration (DR) Event Handling
31  *
32  * Fault manager scheme plug-ins must track characteristics of individual
33  * pieces of hardware.  As these components can be added or removed by a DR
34  * operation, we need to provide a means by which plug-ins can determine when
35  * they need to re-examine the current configuration.  We provide a simple
36  * mechanism whereby this task can be implemented using lazy evaluation: a
37  * simple 64-bit generation counter is maintained and incremented on *any* DR.
38  * Schemes can store the generation number in scheme-specific data structures,
39  * and then revalidate their contents if the current generation number has
40  * changed since the resource information was cached.  This method saves time,
41  * avoids the complexity of direct participation in DR, avoids the need for
42  * resource-specific processing of DR events, and is relatively easy to port
43  * to other systems that support dynamic reconfiguration.
44  */
45 
46 #include <sys/types.h>
47 #include <sys/sysevent/dr.h>
48 #include <sys/sysevent/eventdefs.h>
49 
50 #include <stdio.h>
51 #include <libsysevent.h>
52 
53 #undef MUTEX_HELD
54 #undef RW_READ_HELD
55 #undef RW_WRITE_HELD
56 
57 #include <fmd_error.h>
58 #include <fmd_subr.h>
59 #include <fmd.h>
60 
61 static void
62 fmd_dr_event(sysevent_t *sep)
63 {
64 	uint64_t gen;
65 
66 	(void) pthread_mutex_lock(&fmd.d_stats_lock);
67 	gen = fmd.d_stats->ds_dr_gen.fmds_value.ui64++;
68 	(void) pthread_mutex_unlock(&fmd.d_stats_lock);
69 
70 	TRACE((FMD_DBG_XPRT, "dr event %p, gen=%llu", (void *)sep, gen));
71 }
72 
73 /*
74  * Initialize DR event subscription.  Note: sysevent_bind_handle() calls
75  * door_create() internally.  Door servers in fmd must be setup as fmd threads,
76  * and fmd_transport_init() already calls door_server_create() for us.  We
77  * therefore rely on fmd_transport_init() being called before fmd_dr_init().
78  */
79 void
80 fmd_dr_init(void)
81 {
82 	const char *subclass = ESC_DR_AP_STATE_CHANGE;
83 
84 	ASSERT(fmd.d_xprt_chan != NULL); /* fmd_transport_init() has happened */
85 
86 	if ((fmd.d_dr_hdl = sysevent_bind_handle(fmd_dr_event)) == NULL)
87 		fmd_error(EFMD_EXIT, "failed to bind handle for DR sysevent");
88 
89 	if (sysevent_subscribe_event(fmd.d_dr_hdl, EC_DR, &subclass, 1) == -1)
90 		fmd_error(EFMD_EXIT, "failed to subscribe for DR sysevent");
91 }
92 
93 void
94 fmd_dr_fini(void)
95 {
96 	if (fmd.d_dr_hdl != NULL) {
97 		sysevent_unsubscribe_event(fmd.d_dr_hdl, EC_DR);
98 		sysevent_unbind_handle(fmd.d_dr_hdl);
99 	}
100 }
101