xref: /illumos-gate/usr/src/uts/sparc/dtrace/sdt.c (revision 7c478bd95313f5f23a4c958a745db2134aa03244) 
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 #include <sys/modctl.h>
30 #include <sys/sunddi.h>
31 #include <sys/dtrace.h>
32 #include <sys/kobj.h>
33 #include <sys/stat.h>
34 #include <sys/conf.h>
35 #include <vm/seg_kmem.h>
36 #include <sys/stack.h>
37 #include <sys/sdt_impl.h>
38 
39 static dev_info_t		*sdt_devi;
40 
41 int sdt_verbose = 0;
42 
43 #define	SDT_REG_G0		0
44 #define	SDT_REG_O0		8
45 #define	SDT_REG_O1		9
46 #define	SDT_REG_O2		10
47 #define	SDT_REG_O3		11
48 #define	SDT_REG_O4		12
49 #define	SDT_REG_O5		13
50 #define	SDT_REG_I0		24
51 #define	SDT_REG_I1		25
52 #define	SDT_REG_I2		26
53 #define	SDT_REG_I3		27
54 #define	SDT_REG_I4		28
55 #define	SDT_REG_I5		29
56 
57 #define	SDT_SIMM13_MASK		0x1fff
58 #define	SDT_SIMM13_MAX		((int32_t)0xfff)
59 #define	SDT_CALL(from, to)	(((uint32_t)1 << 30) | \
60 				(((uintptr_t)(to) - (uintptr_t)(from) >> 2) & \
61 				0x3fffffff))
62 #define	SDT_SAVE		(0x9de3a000 | (-SA(MINFRAME) & SDT_SIMM13_MASK))
63 #define	SDT_RET			0x81c7e008
64 #define	SDT_RESTORE		0x81e80000
65 
66 #define	SDT_OP_SETHI		0x1000000
67 #define	SDT_OP_OR		0x80100000
68 
69 #define	SDT_FMT2_RD_SHIFT	25
70 #define	SDT_IMM22_SHIFT		10
71 #define	SDT_IMM22_MASK		0x3fffff
72 #define	SDT_IMM10_MASK		0x3ff
73 
74 #define	SDT_FMT3_RD_SHIFT	25
75 #define	SDT_FMT3_RS1_SHIFT	14
76 #define	SDT_FMT3_RS2_SHIFT	0
77 #define	SDT_FMT3_IMM		(1 << 13)
78 
79 #define	SDT_MOV(rs, rd) \
80 	(SDT_OP_OR | (SDT_REG_G0 << SDT_FMT3_RS1_SHIFT) | \
81 	((rs) << SDT_FMT3_RS2_SHIFT) | ((rd) << SDT_FMT3_RD_SHIFT))
82 
83 #define	SDT_ORLO(rs, val, rd) \
84 	(SDT_OP_OR | ((rs) << SDT_FMT3_RS1_SHIFT) | \
85 	((rd) << SDT_FMT3_RD_SHIFT) | SDT_FMT3_IMM | ((val) & SDT_IMM10_MASK))
86 
87 #define	SDT_ORSIMM13(rs, val, rd) \
88 	(SDT_OP_OR | ((rs) << SDT_FMT3_RS1_SHIFT) | \
89 	((rd) << SDT_FMT3_RD_SHIFT) | SDT_FMT3_IMM | ((val) & SDT_SIMM13_MASK))
90 
91 #define	SDT_SETHI(val, reg)	\
92 	(SDT_OP_SETHI | (reg << SDT_FMT2_RD_SHIFT) | \
93 	((val >> SDT_IMM22_SHIFT) & SDT_IMM22_MASK))
94 
95 #define	SDT_ENTRY_SIZE	(11 * sizeof (uint32_t))
96 
97 static void
98 sdt_initialize(sdt_probe_t *sdp, uint32_t **trampoline)
99 {
100 	uint32_t *instr = *trampoline;
101 
102 	*instr++ = SDT_SAVE;
103 
104 	if (sdp->sdp_id > (uint32_t)SDT_SIMM13_MAX)  {
105 		*instr++ = SDT_SETHI(sdp->sdp_id, SDT_REG_O0);
106 		*instr++ = SDT_ORLO(SDT_REG_O0, sdp->sdp_id, SDT_REG_O0);
107 	} else {
108 		*instr++ = SDT_ORSIMM13(SDT_REG_G0, sdp->sdp_id, SDT_REG_O0);
109 	}
110 
111 	*instr++ = SDT_MOV(SDT_REG_I0, SDT_REG_O1);
112 	*instr++ = SDT_MOV(SDT_REG_I1, SDT_REG_O2);
113 	*instr++ = SDT_MOV(SDT_REG_I2, SDT_REG_O3);
114 	*instr++ = SDT_MOV(SDT_REG_I3, SDT_REG_O4);
115 	*instr = SDT_CALL(instr, dtrace_probe);
116 	instr++;
117 	*instr++ = SDT_MOV(SDT_REG_I4, SDT_REG_O5);
118 
119 	*instr++ = SDT_RET;
120 	*instr++ = SDT_RESTORE;
121 	*trampoline = instr;
122 }
123 
124 /*ARGSUSED*/
125 static void
126 sdt_provide_module(void *arg, struct modctl *ctl)
127 {
128 	struct module *mp = ctl->mod_mp;
129 	char *modname = ctl->mod_modname;
130 	int primary, nprobes = 0;
131 	sdt_probedesc_t *sdpd;
132 	sdt_probe_t *sdp, *old;
133 	uint32_t *tab;
134 	sdt_provider_t *prov;
135 	int len;
136 
137 	/*
138 	 * One for all, and all for one:  if we haven't yet registered all of
139 	 * our providers, we'll refuse to provide anything.
140 	 */
141 	for (prov = sdt_providers; prov->sdtp_name != NULL; prov++) {
142 		if (prov->sdtp_id == DTRACE_PROVNONE)
143 			return;
144 	}
145 
146 	if (mp->sdt_nprobes != 0 || (sdpd = mp->sdt_probes) == NULL)
147 		return;
148 
149 	kobj_textwin_alloc(mp);
150 
151 	/*
152 	 * Hack to identify unix/genunix/krtld.
153 	 */
154 	primary = vmem_contains(heap_arena, (void *)ctl,
155 	    sizeof (struct modctl)) == 0;
156 
157 	/*
158 	 * If there hasn't been an sdt table allocated, we'll do so now.
159 	 */
160 	if (mp->sdt_tab == NULL) {
161 		for (; sdpd != NULL; sdpd = sdpd->sdpd_next) {
162 			nprobes++;
163 		}
164 
165 		/*
166 		 * We could (should?) determine precisely the size of the
167 		 * table -- but a reasonable maximum will suffice.
168 		 */
169 		mp->sdt_size = nprobes * SDT_ENTRY_SIZE;
170 		mp->sdt_tab = kobj_texthole_alloc(mp->text, mp->sdt_size);
171 
172 		if (mp->sdt_tab == NULL) {
173 			cmn_err(CE_WARN, "couldn't allocate SDT table "
174 			    "for module %s", modname);
175 			return;
176 		}
177 	}
178 
179 	tab = (uint32_t *)mp->sdt_tab;
180 
181 	for (sdpd = mp->sdt_probes; sdpd != NULL; sdpd = sdpd->sdpd_next) {
182 		char *name = sdpd->sdpd_name, *func, *nname;
183 		int i, j;
184 		sdt_provider_t *prov;
185 		ulong_t offs;
186 		dtrace_id_t id;
187 
188 		for (prov = sdt_providers; prov->sdtp_prefix != NULL; prov++) {
189 			char *prefix = prov->sdtp_prefix;
190 
191 			if (strncmp(name, prefix, strlen(prefix)) == 0) {
192 				name += strlen(prefix);
193 				break;
194 			}
195 		}
196 
197 		nname = kmem_alloc(len = strlen(name) + 1, KM_SLEEP);
198 
199 		for (i = 0, j = 0; name[j] != '\0'; i++) {
200 			if (name[j] == '_' && name[j + 1] == '_') {
201 				nname[i] = '-';
202 				j += 2;
203 			} else {
204 				nname[i] = name[j++];
205 			}
206 		}
207 
208 		nname[i] = '\0';
209 
210 		sdp = kmem_zalloc(sizeof (sdt_probe_t), KM_SLEEP);
211 		sdp->sdp_loadcnt = ctl->mod_loadcnt;
212 		sdp->sdp_primary = primary;
213 		sdp->sdp_ctl = ctl;
214 		sdp->sdp_name = nname;
215 		sdp->sdp_namelen = len;
216 		sdp->sdp_provider = prov;
217 
218 		func = kobj_searchsym(mp, sdpd->sdpd_offset +
219 		    (uintptr_t)mp->text, &offs);
220 
221 		if (func == NULL)
222 			func = "<unknown>";
223 
224 		/*
225 		 * We have our provider.  Now create the probe.
226 		 */
227 		if ((id = dtrace_probe_lookup(prov->sdtp_id, modname,
228 		    func, nname)) != DTRACE_IDNONE) {
229 			old = dtrace_probe_arg(prov->sdtp_id, id);
230 			ASSERT(old != NULL);
231 
232 			sdp->sdp_next = old->sdp_next;
233 			sdp->sdp_id = id;
234 			old->sdp_next = sdp;
235 		} else {
236 			sdp->sdp_id = dtrace_probe_create(prov->sdtp_id,
237 			    modname, func, nname, 1, sdp);
238 
239 			mp->sdt_nprobes++;
240 		}
241 
242 		sdp->sdp_patchval = SDT_CALL((uintptr_t)mp->text +
243 		    sdpd->sdpd_offset, tab);
244 		sdp->sdp_patchpoint = (uint32_t *)((uintptr_t)mp->textwin +
245 		    sdpd->sdpd_offset);
246 		sdp->sdp_savedval = *sdp->sdp_patchpoint;
247 		sdt_initialize(sdp, &tab);
248 	}
249 }
250 
251 /*ARGSUSED*/
252 static void
253 sdt_destroy(void *arg, dtrace_id_t id, void *parg)
254 {
255 	sdt_probe_t *sdp = parg, *old;
256 	struct modctl *ctl = sdp->sdp_ctl;
257 
258 	if (ctl != NULL && ctl->mod_loadcnt == sdp->sdp_loadcnt) {
259 		if ((ctl->mod_loadcnt == sdp->sdp_loadcnt &&
260 		    ctl->mod_loaded) || sdp->sdp_primary) {
261 			((struct module *)(ctl->mod_mp))->sdt_nprobes--;
262 		}
263 	}
264 
265 	while (sdp != NULL) {
266 		old = sdp;
267 		kmem_free(sdp->sdp_name, sdp->sdp_namelen);
268 		sdp = sdp->sdp_next;
269 		kmem_free(old, sizeof (sdt_probe_t));
270 	}
271 }
272 
273 /*ARGSUSED*/
274 static void
275 sdt_enable(void *arg, dtrace_id_t id, void *parg)
276 {
277 	sdt_probe_t *sdp = parg;
278 	struct modctl *ctl = sdp->sdp_ctl;
279 
280 	ctl->mod_nenabled++;
281 
282 	/*
283 	 * If this module has disappeared since we discovered its probes,
284 	 * refuse to enable it.
285 	 */
286 	if (!sdp->sdp_primary && !ctl->mod_loaded) {
287 		if (sdt_verbose) {
288 			cmn_err(CE_NOTE, "sdt is failing for probe %s "
289 			    "(module %s unloaded)",
290 			    sdp->sdp_name, ctl->mod_modname);
291 		}
292 		goto err;
293 	}
294 
295 	/*
296 	 * Now check that our modctl has the expected load count.  If it
297 	 * doesn't, this module must have been unloaded and reloaded -- and
298 	 * we're not going to touch it.
299 	 */
300 	if (ctl->mod_loadcnt != sdp->sdp_loadcnt) {
301 		if (sdt_verbose) {
302 			cmn_err(CE_NOTE, "sdt is failing for probe %s "
303 			    "(module %s reloaded)",
304 			    sdp->sdp_name, ctl->mod_modname);
305 		}
306 		goto err;
307 	}
308 
309 	while (sdp != NULL) {
310 		*sdp->sdp_patchpoint = sdp->sdp_patchval;
311 		sdp = sdp->sdp_next;
312 	}
313 
314 err:
315 	;
316 }
317 
318 /*ARGSUSED*/
319 static void
320 sdt_disable(void *arg, dtrace_id_t id, void *parg)
321 {
322 	sdt_probe_t *sdp = parg;
323 	struct modctl *ctl = sdp->sdp_ctl;
324 
325 	ASSERT(ctl->mod_nenabled > 0);
326 	ctl->mod_nenabled--;
327 
328 	if ((!sdp->sdp_primary && !ctl->mod_loaded) ||
329 	    (ctl->mod_loadcnt != sdp->sdp_loadcnt))
330 		goto err;
331 
332 	while (sdp != NULL) {
333 		*sdp->sdp_patchpoint = sdp->sdp_savedval;
334 		sdp = sdp->sdp_next;
335 	}
336 
337 err:
338 	;
339 }
340 
341 static dtrace_pops_t sdt_pops = {
342 	NULL,
343 	sdt_provide_module,
344 	sdt_enable,
345 	sdt_disable,
346 	NULL,
347 	NULL,
348 	sdt_getargdesc,
349 	NULL,
350 	NULL,
351 	sdt_destroy
352 };
353 
354 static int
355 sdt_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
356 {
357 	sdt_provider_t *prov;
358 
359 	switch (cmd) {
360 	case DDI_ATTACH:
361 		break;
362 	case DDI_RESUME:
363 		return (DDI_SUCCESS);
364 	default:
365 		return (DDI_FAILURE);
366 	}
367 
368 	if (ddi_create_minor_node(devi, "sdt", S_IFCHR, 0,
369 	    DDI_PSEUDO, NULL) == DDI_FAILURE) {
370 		ddi_remove_minor_node(devi, NULL);
371 		return (DDI_FAILURE);
372 	}
373 
374 	ddi_report_dev(devi);
375 	sdt_devi = devi;
376 
377 	for (prov = sdt_providers; prov->sdtp_name != NULL; prov++) {
378 		if (dtrace_register(prov->sdtp_name, prov->sdtp_attr,
379 		    DTRACE_PRIV_KERNEL, 0,
380 		    &sdt_pops, prov, &prov->sdtp_id) != 0) {
381 			cmn_err(CE_WARN, "failed to register sdt provider %s",
382 			    prov->sdtp_name);
383 		}
384 	}
385 
386 	return (DDI_SUCCESS);
387 }
388 
389 static int
390 sdt_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
391 {
392 	sdt_provider_t *prov;
393 
394 	switch (cmd) {
395 	case DDI_DETACH:
396 		break;
397 	case DDI_SUSPEND:
398 		return (DDI_SUCCESS);
399 	default:
400 		return (DDI_FAILURE);
401 	}
402 
403 	for (prov = sdt_providers; prov->sdtp_name != NULL; prov++) {
404 		if (prov->sdtp_id != DTRACE_PROVNONE) {
405 			if (dtrace_unregister(prov->sdtp_id) != 0)
406 				return (DDI_FAILURE);
407 			prov->sdtp_id = DTRACE_PROVNONE;
408 		}
409 	}
410 
411 	ddi_remove_minor_node(devi, NULL);
412 	return (DDI_SUCCESS);
413 }
414 
415 /*ARGSUSED*/
416 static int
417 sdt_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result)
418 {
419 	int error;
420 
421 	switch (infocmd) {
422 	case DDI_INFO_DEVT2DEVINFO:
423 		*result = (void *)sdt_devi;
424 		error = DDI_SUCCESS;
425 		break;
426 	case DDI_INFO_DEVT2INSTANCE:
427 		*result = (void *)0;
428 		error = DDI_SUCCESS;
429 		break;
430 	default:
431 		error = DDI_FAILURE;
432 	}
433 	return (error);
434 }
435 
436 /*ARGSUSED*/
437 static int
438 sdt_open(dev_t *devp, int flag, int otyp, cred_t *cred_p)
439 {
440 	return (0);
441 }
442 
443 static struct cb_ops sdt_cb_ops = {
444 	sdt_open,		/* open */
445 	nodev,			/* close */
446 	nulldev,		/* strategy */
447 	nulldev,		/* print */
448 	nodev,			/* dump */
449 	nodev,			/* read */
450 	nodev,			/* write */
451 	nodev,			/* ioctl */
452 	nodev,			/* devmap */
453 	nodev,			/* mmap */
454 	nodev,			/* segmap */
455 	nochpoll,		/* poll */
456 	ddi_prop_op,		/* cb_prop_op */
457 	0,			/* streamtab  */
458 	D_NEW | D_MP		/* Driver compatibility flag */
459 };
460 
461 static struct dev_ops sdt_ops = {
462 	DEVO_REV,		/* devo_rev, */
463 	0,			/* refcnt  */
464 	sdt_info,		/* get_dev_info */
465 	nulldev,		/* identify */
466 	nulldev,		/* probe */
467 	sdt_attach,		/* attach */
468 	sdt_detach,		/* detach */
469 	nodev,			/* reset */
470 	&sdt_cb_ops,		/* driver operations */
471 	NULL,			/* bus operations */
472 	nodev			/* dev power */
473 };
474 
475 /*
476  * Module linkage information for the kernel.
477  */
478 static struct modldrv modldrv = {
479 	&mod_driverops,		/* module type (this is a pseudo driver) */
480 	"Statically Defined Tracing",	/* name of module */
481 	&sdt_ops,		/* driver ops */
482 };
483 
484 static struct modlinkage modlinkage = {
485 	MODREV_1,
486 	(void *)&modldrv,
487 	NULL
488 };
489 
490 int
491 _init(void)
492 {
493 	return (mod_install(&modlinkage));
494 }
495 
496 int
497 _info(struct modinfo *modinfop)
498 {
499 	return (mod_info(&modlinkage, modinfop));
500 }
501 
502 int
503 _fini(void)
504 {
505 	return (mod_remove(&modlinkage));
506 }
507