xref: /freebsd/sys/cddl/dev/dtrace/dtrace_load.c (revision 3fc9e2c36555140de248a0b4def91bbfa44d7c2c)
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 	/* Register callbacks for linker file load and unload events. */
60 	dtrace_kld_load_tag = EVENTHANDLER_REGISTER(kld_load,
61 	    dtrace_kld_load, NULL, EVENTHANDLER_PRI_ANY);
62 	dtrace_kld_unload_try_tag = EVENTHANDLER_REGISTER(kld_unload_try,
63 	    dtrace_kld_unload_try, NULL, EVENTHANDLER_PRI_ANY);
64 
65 	/*
66 	 * Initialise the mutexes without 'witness' because the dtrace
67 	 * code is mostly written to wait for memory. To have the
68 	 * witness code change a malloc() from M_WAITOK to M_NOWAIT
69 	 * because a lock is held would surely create a panic in a
70 	 * low memory situation. And that low memory situation might be
71 	 * the very problem we are trying to trace.
72 	 */
73 	mutex_init(&dtrace_lock,"dtrace probe state", MUTEX_DEFAULT, NULL);
74 	mutex_init(&dtrace_provider_lock,"dtrace provider state", MUTEX_DEFAULT, NULL);
75 	mutex_init(&dtrace_meta_lock,"dtrace meta-provider state", MUTEX_DEFAULT, NULL);
76 #ifdef DEBUG
77 	mutex_init(&dtrace_errlock,"dtrace error lock", MUTEX_DEFAULT, NULL);
78 #endif
79 
80 	mutex_enter(&dtrace_provider_lock);
81 	mutex_enter(&dtrace_lock);
82 	mutex_enter(&cpu_lock);
83 
84 	ASSERT(MUTEX_HELD(&cpu_lock));
85 
86 	dtrace_arena = new_unrhdr(1, INT_MAX, &dtrace_unr_mtx);
87 
88 	dtrace_state_cache = kmem_cache_create("dtrace_state_cache",
89 	    sizeof (dtrace_dstate_percpu_t) * NCPU, DTRACE_STATE_ALIGN,
90 	    NULL, NULL, NULL, NULL, NULL, 0);
91 
92 	ASSERT(MUTEX_HELD(&cpu_lock));
93 	dtrace_bymod = dtrace_hash_create(offsetof(dtrace_probe_t, dtpr_mod),
94 	    offsetof(dtrace_probe_t, dtpr_nextmod),
95 	    offsetof(dtrace_probe_t, dtpr_prevmod));
96 
97 	dtrace_byfunc = dtrace_hash_create(offsetof(dtrace_probe_t, dtpr_func),
98 	    offsetof(dtrace_probe_t, dtpr_nextfunc),
99 	    offsetof(dtrace_probe_t, dtpr_prevfunc));
100 
101 	dtrace_byname = dtrace_hash_create(offsetof(dtrace_probe_t, dtpr_name),
102 	    offsetof(dtrace_probe_t, dtpr_nextname),
103 	    offsetof(dtrace_probe_t, dtpr_prevname));
104 
105 	if (dtrace_retain_max < 1) {
106 		cmn_err(CE_WARN, "illegal value (%lu) for dtrace_retain_max; "
107 		    "setting to 1", dtrace_retain_max);
108 		dtrace_retain_max = 1;
109 	}
110 
111 	/*
112 	 * Now discover our toxic ranges.
113 	 */
114 	dtrace_toxic_ranges(dtrace_toxrange_add);
115 
116 	/*
117 	 * Before we register ourselves as a provider to our own framework,
118 	 * we would like to assert that dtrace_provider is NULL -- but that's
119 	 * not true if we were loaded as a dependency of a DTrace provider.
120 	 * Once we've registered, we can assert that dtrace_provider is our
121 	 * pseudo provider.
122 	 */
123 	(void) dtrace_register("dtrace", &dtrace_provider_attr,
124 	    DTRACE_PRIV_NONE, 0, &dtrace_provider_ops, NULL, &id);
125 
126 	ASSERT(dtrace_provider != NULL);
127 	ASSERT((dtrace_provider_id_t)dtrace_provider == id);
128 
129 	dtrace_probeid_begin = dtrace_probe_create((dtrace_provider_id_t)
130 	    dtrace_provider, NULL, NULL, "BEGIN", 0, NULL);
131 	dtrace_probeid_end = dtrace_probe_create((dtrace_provider_id_t)
132 	    dtrace_provider, NULL, NULL, "END", 0, NULL);
133 	dtrace_probeid_error = dtrace_probe_create((dtrace_provider_id_t)
134 	    dtrace_provider, NULL, NULL, "ERROR", 1, NULL);
135 
136 	mutex_exit(&cpu_lock);
137 
138 	/*
139 	 * If DTrace helper tracing is enabled, we need to allocate the
140 	 * trace buffer and initialize the values.
141 	 */
142 	if (dtrace_helptrace_enabled) {
143 		ASSERT(dtrace_helptrace_buffer == NULL);
144 		dtrace_helptrace_buffer =
145 		    kmem_zalloc(dtrace_helptrace_bufsize, KM_SLEEP);
146 		dtrace_helptrace_next = 0;
147 	}
148 
149 	mutex_exit(&dtrace_lock);
150 	mutex_exit(&dtrace_provider_lock);
151 
152 	mutex_enter(&cpu_lock);
153 
154 	/* Setup the boot CPU */
155 	(void) dtrace_cpu_setup(CPU_CONFIG, 0);
156 
157 	mutex_exit(&cpu_lock);
158 
159 #if __FreeBSD_version < 800039
160 	/* Enable device cloning. */
161 	clone_setup(&dtrace_clones);
162 
163 	/* Setup device cloning events. */
164 	eh_tag = EVENTHANDLER_REGISTER(dev_clone, dtrace_clone, 0, 1000);
165 #else
166 	dtrace_dev = make_dev(&dtrace_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600,
167 	    "dtrace/dtrace");
168 	helper_dev = make_dev(&helper_cdevsw, 0, UID_ROOT, GID_WHEEL, 0660,
169 	    "dtrace/helper");
170 #endif
171 
172 	return;
173 }
174