xref: /illumos-gate/usr/src/cmd/mdb/common/kmdb/kctl/kctl_wr.c (revision 2a8bcb4efb45d99ac41c94a75c396b362c414f7f)
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 2007 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  * Copyright (c) 2016 by Delphix. All rights reserved.
25  */
26 
27 /*
28  * Implements the kernel side of the debugger/kernel work queue.
29  */
30 
31 #include <kmdb/kmdb_kdi.h>
32 #include <kmdb/kctl/kctl.h>
33 #include <kmdb/kctl/kctl_wr.h>
34 
35 #include <sys/proc.h>
36 #include <sys/disp.h>
37 #include <sys/kdi_impl.h>
38 #include <sys/callb.h>
39 
40 #define	KCTL_WR_PROCESS_NORMAL		(void *)0
41 #define	KCTL_WR_PROCESS_UNLOADING	(void *)1
42 
43 /*
44  * Processes events from the debugger -> driver notification queue.  Returns
45  * 1 if the debugger should be awakened after the queue has been processed.
46  */
47 static int
kctl_wr_process_cb(kmdb_wr_t * wn,void * arg)48 kctl_wr_process_cb(kmdb_wr_t *wn, void *arg)
49 {
50 	int unloading = (arg == KCTL_WR_PROCESS_UNLOADING);
51 
52 	switch (WR_TASK(wn)) {
53 	case WNTASK_DMOD_LOAD: {
54 		/*
55 		 * If this is an ack, then we're getting back a message from a
56 		 * load we initiated.  Free it.  If it's not an ack, we process
57 		 * the message (attempt to load the requested module) and send
58 		 * an ack back to the debugger.
59 		 */
60 		kmdb_wr_load_t *dlr = (kmdb_wr_load_t *)wn;
61 
62 		if (WR_ISACK(dlr)) {
63 			kctl_dprintf("received ack for dmod load of %s",
64 			    dlr->dlr_fname);
65 			kctl_dmod_load_ack(dlr);
66 			return (0);
67 		} else
68 			kctl_dprintf("received dmod load request %s",
69 			    dlr->dlr_fname);
70 
71 		if (unloading) {
72 			/*
73 			 * If the user didn't wait for all dmods to load before
74 			 * they triggered the debugger unload, we may have some
75 			 * dmod load requests on the queue in front of the
76 			 * blizzard of dmod unload requests that the debugger
77 			 * will generate as part of its unload.  The debugger
78 			 * won't have generated unloads for pending dmods, so
79 			 * we can safely ignore the load requests.
80 			 */
81 			kctl_dprintf("skipping load of dmod %s due to "
82 			    "in-process unload");
83 		} else
84 			(void) kctl_dmod_load(dlr); /* dlr will have errno */
85 
86 		WR_ACK(dlr);
87 		kmdb_wr_debugger_notify(dlr);
88 		return (1);
89 	}
90 
91 	case WNTASK_DMOD_LOAD_ALL:
92 		/*
93 		 * We don't initiate all-module loads, so this can't be an
94 		 * ack.  We process the load-all, and send the message back
95 		 * to the driver as an ack.
96 		 */
97 		ASSERT(!WR_ISACK(wn));
98 
99 		kctl_dprintf("received request to load all dmods");
100 
101 		(void) kctl_dmod_load_all();
102 
103 		WR_ACK(wn);
104 		kmdb_wr_debugger_notify(wn);
105 		return (1);
106 
107 	case WNTASK_DMOD_UNLOAD: {
108 		/*
109 		 * The driver received an unload request.  We don't initiate
110 		 * unloads, so this can't be an ack.  We process the unload,
111 		 * and send the message back to the driver as an ack.
112 		 */
113 		kmdb_wr_unload_t *dur = (kmdb_wr_unload_t *)wn;
114 
115 		ASSERT(!WR_ISACK(dur));
116 		ASSERT(kctl.kctl_boot_ops == NULL);
117 
118 		kctl_dprintf("received dmod unload message %s",
119 		    dur->dur_modname);
120 
121 		kctl_dmod_unload(dur);
122 
123 		WR_ACK(dur);
124 		kmdb_wr_debugger_notify(dur);
125 		return (1);
126 	}
127 
128 	case WNTASK_DMOD_PATH_CHANGE: {
129 		/*
130 		 * We don't initiate path changes, so this can't be an ack.
131 		 * This request type differs from the others in that we only
132 		 * return it (as an ack) when we're done with it.  We're only
133 		 * done with it when we receive another one, or when the
134 		 * debugger is unloading.
135 		 */
136 		kmdb_wr_path_t *pth = (kmdb_wr_path_t *)wn;
137 		kmdb_wr_path_t *opth;
138 
139 		ASSERT(!WR_ISACK(pth));
140 
141 		kctl_dprintf("received path change message");
142 
143 		if ((opth = kctl_dmod_path_set(pth)) != NULL) {
144 			/* We have an old path request to return */
145 			WR_ACK(opth);
146 			kmdb_wr_debugger_notify(opth);
147 
148 			/*
149 			 * The debugger can process the returned path change
150 			 * request at its leisure
151 			 */
152 			return (0);
153 		}
154 
155 		/* Nothing to do */
156 		return (0);
157 	}
158 
159 	default:
160 		cmn_err(CE_WARN, "Received unknown work request %d from kmdb\n",
161 		    wn->wn_task);
162 		/* Drop message */
163 		return (0);
164 	}
165 
166 	/*NOTREACHED*/
167 }
168 
169 int
kctl_wr_process(void)170 kctl_wr_process(void)
171 {
172 	return (kmdb_wr_driver_process(kctl_wr_process_cb,
173 	    KCTL_WR_PROCESS_NORMAL));
174 }
175 
176 /*
177  * Catches the "work to do" soft interrupt, and passes the notification along
178  * to the worker thread.
179  */
180 /*ARGSUSED*/
181 void
kctl_wrintr(void)182 kctl_wrintr(void)
183 {
184 	kctl.kctl_wr_avail = 0;
185 
186 	sema_v(&kctl.kctl_wr_avail_sem);
187 }
188 
189 /*
190  * This routine is called by the debugger while the world is resuming.
191  */
192 void
kctl_wrintr_fire(void)193 kctl_wrintr_fire(void)
194 {
195 	kctl.kctl_wr_avail = 1;
196 
197 	kdi_softcall(kctl_wrintr);
198 }
199 
200 /*
201  * Given the possibility of asynchronous unload, the locking semantics are
202  * somewhat tricky.  See kctl_main.c
203  */
204 /*ARGSUSED*/
205 static void
kctl_wr_thread(void * arg)206 kctl_wr_thread(void *arg)
207 {
208 	callb_cpr_t cprinfo;
209 	kmutex_t cprlock;
210 
211 	mutex_init(&cprlock, NULL, MUTEX_DEFAULT, NULL);
212 	CALLB_CPR_INIT(&cprinfo, &cprlock, callb_generic_cpr, "kmdb work");
213 
214 	for (;;) {
215 		/*
216 		 * XXX what should I do here for panic?  It'll spin unless I
217 		 * can figure out a way to park it.  Presumably I don't want to
218 		 * let it exit.
219 		 */
220 		mutex_enter(&cprlock);
221 		CALLB_CPR_SAFE_BEGIN(&cprinfo);
222 		mutex_exit(&cprlock);
223 
224 		sema_p(&kctl.kctl_wr_avail_sem);
225 
226 		mutex_enter(&cprlock);
227 		CALLB_CPR_SAFE_END(&cprinfo, &cprlock);
228 		mutex_exit(&cprlock);
229 
230 		kctl_dprintf("kctl worker thread - waking up");
231 
232 		if (kmdb_kdi_get_unload_request() ||
233 		    kctl.kctl_wr_state != KCTL_WR_ST_RUN) {
234 			/*
235 			 * We've either got a debugger-initiated unload (if
236 			 * unload_request returned true), or we're stopping due
237 			 * to an error discovered by the driver (if
238 			 * kctl_worker_run is no longer non-zero).  Start
239 			 * cleaning up.
240 			 */
241 
242 			/*
243 			 * The debugger has already deactivated itself, and will
244 			 * have dumped a bunch of stuff on the queue.  We need
245 			 * to process it before exiting.
246 			 */
247 			(void) kmdb_wr_driver_process(kctl_wr_process_cb,
248 			    KCTL_WR_PROCESS_UNLOADING);
249 			break;
250 		}
251 
252 		/*
253 		 * A non-zero return means we've passed messages back to the
254 		 * debugger for processing, so we need to wake the debugger up.
255 		 */
256 		if (kctl_wr_process() > 0)
257 			kmdb_kdi_kmdb_enter();
258 	}
259 
260 	/*
261 	 * NULL out the dmod search path, so we can send the current one back
262 	 * to the debugger.  XXX this should probably be somewhere else.
263 	 */
264 	kctl_dmod_path_reset();
265 
266 	/*
267 	 * The debugger will send us unload notifications for each dmod that it
268 	 * noticed.  If, for example, the debugger is unloaded before the first
269 	 * start, it won't have noticed any of the dmods we loaded.  We'll need
270 	 * to initiate the unloads ourselves.
271 	 */
272 	kctl_dmod_unload_all();
273 
274 	kctl.kctl_wr_state = KCTL_WR_ST_STOPPED;
275 
276 	/*
277 	 * Must be last, as it concludes by setting state to INACTIVE.  The
278 	 * kctl data structure must not be accessed by this thread after that
279 	 * point.
280 	 */
281 	kctl_cleanup();
282 
283 	mutex_enter(&cprlock);
284 	CALLB_CPR_EXIT(&cprinfo);
285 	mutex_destroy(&cprlock);
286 }
287 
288 void
kctl_wr_thr_start(void)289 kctl_wr_thr_start(void)
290 {
291 	kctl.kctl_wr_avail = 0;
292 	kctl.kctl_wr_state = KCTL_WR_ST_RUN;
293 	kctl.kctl_wr_thr = thread_create(NULL, 0, kctl_wr_thread, NULL, 0, &p0,
294 	    TS_RUN, minclsyspri);
295 }
296 
297 void
kctl_wr_thr_stop(void)298 kctl_wr_thr_stop(void)
299 {
300 	ASSERT(kctl.kctl_wr_state == KCTL_WR_ST_RUN);
301 	kctl.kctl_wr_state = KCTL_WR_ST_STOP;
302 	sema_v(&kctl.kctl_wr_avail_sem);
303 }
304 
305 void
kctl_wr_thr_join(void)306 kctl_wr_thr_join(void)
307 {
308 	thread_join(kctl.kctl_wr_thr->t_did);
309 }
310