xref: /freebsd/sys/cddl/dev/dtrace/dtrace_load.c (revision a98ff317388a00b992f1bf8404dee596f9383f5e)
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  * $FreeBSD$
22  *
23  */
24 
25 static void
26 dtrace_ap_start(void *dummy)
27 {
28 	int i;
29 
30 	mutex_enter(&cpu_lock);
31 
32 	/* Setup the rest of the CPUs. */
33 	CPU_FOREACH(i) {
34 		if (i == 0)
35 			continue;
36 
37 		(void) dtrace_cpu_setup(CPU_CONFIG, i);
38 	}
39 
40 	mutex_exit(&cpu_lock);
41 }
42 
43 SYSINIT(dtrace_ap_start, SI_SUB_SMP, SI_ORDER_ANY, dtrace_ap_start, NULL);
44 
45 static void
46 dtrace_load(void *dummy)
47 {
48 	dtrace_provider_id_t id;
49 
50 	/* Hook into the trap handler. */
51 	dtrace_trap_func = dtrace_trap;
52 
53 	/* Hang our hook for thread switches. */
54 	dtrace_vtime_switch_func = dtrace_vtime_switch;
55 
56 	/* Hang our hook for exceptions. */
57 	dtrace_invop_init();
58 
59 	/*
60 	 * Initialise the mutexes without 'witness' because the dtrace
61 	 * code is mostly written to wait for memory. To have the
62 	 * witness code change a malloc() from M_WAITOK to M_NOWAIT
63 	 * because a lock is held would surely create a panic in a
64 	 * low memory situation. And that low memory situation might be
65 	 * the very problem we are trying to trace.
66 	 */
67 	mutex_init(&dtrace_lock,"dtrace probe state", MUTEX_DEFAULT, NULL);
68 	mutex_init(&dtrace_provider_lock,"dtrace provider state", MUTEX_DEFAULT, NULL);
69 	mutex_init(&dtrace_meta_lock,"dtrace meta-provider state", MUTEX_DEFAULT, NULL);
70 	mutex_init(&dtrace_errlock,"dtrace error lock", MUTEX_DEFAULT, NULL);
71 
72 	mutex_enter(&dtrace_provider_lock);
73 	mutex_enter(&dtrace_lock);
74 	mutex_enter(&cpu_lock);
75 
76 	ASSERT(MUTEX_HELD(&cpu_lock));
77 
78 	dtrace_arena = new_unrhdr(1, INT_MAX, &dtrace_unr_mtx);
79 
80 	dtrace_state_cache = kmem_cache_create("dtrace_state_cache",
81 	    sizeof (dtrace_dstate_percpu_t) * NCPU, DTRACE_STATE_ALIGN,
82 	    NULL, NULL, NULL, NULL, NULL, 0);
83 
84 	ASSERT(MUTEX_HELD(&cpu_lock));
85 	dtrace_bymod = dtrace_hash_create(offsetof(dtrace_probe_t, dtpr_mod),
86 	    offsetof(dtrace_probe_t, dtpr_nextmod),
87 	    offsetof(dtrace_probe_t, dtpr_prevmod));
88 
89 	dtrace_byfunc = dtrace_hash_create(offsetof(dtrace_probe_t, dtpr_func),
90 	    offsetof(dtrace_probe_t, dtpr_nextfunc),
91 	    offsetof(dtrace_probe_t, dtpr_prevfunc));
92 
93 	dtrace_byname = dtrace_hash_create(offsetof(dtrace_probe_t, dtpr_name),
94 	    offsetof(dtrace_probe_t, dtpr_nextname),
95 	    offsetof(dtrace_probe_t, dtpr_prevname));
96 
97 	if (dtrace_retain_max < 1) {
98 		cmn_err(CE_WARN, "illegal value (%lu) for dtrace_retain_max; "
99 		    "setting to 1", dtrace_retain_max);
100 		dtrace_retain_max = 1;
101 	}
102 
103 	/*
104 	 * Now discover our toxic ranges.
105 	 */
106 	dtrace_toxic_ranges(dtrace_toxrange_add);
107 
108 	/*
109 	 * Before we register ourselves as a provider to our own framework,
110 	 * we would like to assert that dtrace_provider is NULL -- but that's
111 	 * not true if we were loaded as a dependency of a DTrace provider.
112 	 * Once we've registered, we can assert that dtrace_provider is our
113 	 * pseudo provider.
114 	 */
115 	(void) dtrace_register("dtrace", &dtrace_provider_attr,
116 	    DTRACE_PRIV_NONE, 0, &dtrace_provider_ops, NULL, &id);
117 
118 	ASSERT(dtrace_provider != NULL);
119 	ASSERT((dtrace_provider_id_t)dtrace_provider == id);
120 
121 	dtrace_probeid_begin = dtrace_probe_create((dtrace_provider_id_t)
122 	    dtrace_provider, NULL, NULL, "BEGIN", 0, NULL);
123 	dtrace_probeid_end = dtrace_probe_create((dtrace_provider_id_t)
124 	    dtrace_provider, NULL, NULL, "END", 0, NULL);
125 	dtrace_probeid_error = dtrace_probe_create((dtrace_provider_id_t)
126 	    dtrace_provider, NULL, NULL, "ERROR", 1, NULL);
127 
128 	mutex_exit(&cpu_lock);
129 
130 	/*
131 	 * If DTrace helper tracing is enabled, we need to allocate the
132 	 * trace buffer and initialize the values.
133 	 */
134 	if (dtrace_helptrace_enabled) {
135 		ASSERT(dtrace_helptrace_buffer == NULL);
136 		dtrace_helptrace_buffer =
137 		    kmem_zalloc(dtrace_helptrace_bufsize, KM_SLEEP);
138 		dtrace_helptrace_next = 0;
139 	}
140 
141 	mutex_exit(&dtrace_lock);
142 	mutex_exit(&dtrace_provider_lock);
143 
144 	mutex_enter(&cpu_lock);
145 
146 	/* Setup the boot CPU */
147 	(void) dtrace_cpu_setup(CPU_CONFIG, 0);
148 
149 	mutex_exit(&cpu_lock);
150 
151 #if __FreeBSD_version < 800039
152 	/* Enable device cloning. */
153 	clone_setup(&dtrace_clones);
154 
155 	/* Setup device cloning events. */
156 	eh_tag = EVENTHANDLER_REGISTER(dev_clone, dtrace_clone, 0, 1000);
157 #else
158 	dtrace_dev = make_dev(&dtrace_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600,
159 	    "dtrace/dtrace");
160 	helper_dev = make_dev(&helper_cdevsw, 0, UID_ROOT, GID_WHEEL, 0660,
161 	    "dtrace/helper");
162 #endif
163 
164 	return;
165 }
166