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/*
23 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27/*
28 * Copyright 2017 Joyent, Inc.
29 * Copyright (c) 2012 by Delphix. All rights reserved.
30 */
31
32#ifndef _SYS_DTRACE_IMPL_H
33#define	_SYS_DTRACE_IMPL_H
34
35#ifdef	__cplusplus
36extern "C" {
37#endif
38
39/*
40 * DTrace Dynamic Tracing Software: Kernel Implementation Interfaces
41 *
42 * Note: The contents of this file are private to the implementation of the
43 * Solaris system and DTrace subsystem and are subject to change at any time
44 * without notice.  Applications and drivers using these interfaces will fail
45 * to run on future releases.  These interfaces should not be used for any
46 * purpose except those expressly outlined in dtrace(7D) and libdtrace(3LIB).
47 * Please refer to the "Solaris Dynamic Tracing Guide" for more information.
48 */
49
50#include <sys/dtrace.h>
51
52/*
53 * DTrace Implementation Constants and Typedefs
54 */
55#define	DTRACE_MAXPROPLEN		128
56#define	DTRACE_DYNVAR_CHUNKSIZE		256
57
58struct dtrace_probe;
59struct dtrace_ecb;
60struct dtrace_predicate;
61struct dtrace_action;
62struct dtrace_provider;
63struct dtrace_state;
64
65typedef struct dtrace_probe dtrace_probe_t;
66typedef struct dtrace_ecb dtrace_ecb_t;
67typedef struct dtrace_predicate dtrace_predicate_t;
68typedef struct dtrace_action dtrace_action_t;
69typedef struct dtrace_provider dtrace_provider_t;
70typedef struct dtrace_meta dtrace_meta_t;
71typedef struct dtrace_state dtrace_state_t;
72typedef uint32_t dtrace_optid_t;
73typedef uint32_t dtrace_specid_t;
74typedef uint64_t dtrace_genid_t;
75
76/*
77 * DTrace Probes
78 *
79 * The probe is the fundamental unit of the DTrace architecture.  Probes are
80 * created by DTrace providers, and managed by the DTrace framework.  A probe
81 * is identified by a unique <provider, module, function, name> tuple, and has
82 * a unique probe identifier assigned to it.  (Some probes are not associated
83 * with a specific point in text; these are called _unanchored probes_ and have
84 * no module or function associated with them.)  Probes are represented as a
85 * dtrace_probe structure.  To allow quick lookups based on each element of the
86 * probe tuple, probes are hashed by each of provider, module, function and
87 * name.  (If a lookup is performed based on a regular expression, a
88 * dtrace_probekey is prepared, and a linear search is performed.) Each probe
89 * is additionally pointed to by a linear array indexed by its identifier.  The
90 * identifier is the provider's mechanism for indicating to the DTrace
91 * framework that a probe has fired:  the identifier is passed as the first
92 * argument to dtrace_probe(), where it is then mapped into the corresponding
93 * dtrace_probe structure.  From the dtrace_probe structure, dtrace_probe() can
94 * iterate over the probe's list of enabling control blocks; see "DTrace
95 * Enabling Control Blocks", below.)
96 */
97struct dtrace_probe {
98	dtrace_id_t dtpr_id;			/* probe identifier */
99	dtrace_ecb_t *dtpr_ecb;			/* ECB list; see below */
100	dtrace_ecb_t *dtpr_ecb_last;		/* last ECB in list */
101	void *dtpr_arg;				/* provider argument */
102	dtrace_cacheid_t dtpr_predcache;	/* predicate cache ID */
103	int dtpr_aframes;			/* artificial frames */
104	dtrace_provider_t *dtpr_provider;	/* pointer to provider */
105	char *dtpr_mod;				/* probe's module name */
106	char *dtpr_func;			/* probe's function name */
107	char *dtpr_name;			/* probe's name */
108	dtrace_probe_t *dtpr_nextmod;		/* next in module hash */
109	dtrace_probe_t *dtpr_prevmod;		/* previous in module hash */
110	dtrace_probe_t *dtpr_nextfunc;		/* next in function hash */
111	dtrace_probe_t *dtpr_prevfunc;		/* previous in function hash */
112	dtrace_probe_t *dtpr_nextname;		/* next in name hash */
113	dtrace_probe_t *dtpr_prevname;		/* previous in name hash */
114	dtrace_genid_t dtpr_gen;		/* probe generation ID */
115};
116
117typedef int dtrace_probekey_f(const char *, const char *, int);
118
119typedef struct dtrace_probekey {
120	const char *dtpk_prov;			/* provider name to match */
121	dtrace_probekey_f *dtpk_pmatch;		/* provider matching function */
122	const char *dtpk_mod;			/* module name to match */
123	dtrace_probekey_f *dtpk_mmatch;		/* module matching function */
124	const char *dtpk_func;			/* func name to match */
125	dtrace_probekey_f *dtpk_fmatch;		/* func matching function */
126	const char *dtpk_name;			/* name to match */
127	dtrace_probekey_f *dtpk_nmatch;		/* name matching function */
128	dtrace_id_t dtpk_id;			/* identifier to match */
129} dtrace_probekey_t;
130
131typedef struct dtrace_hashbucket {
132	struct dtrace_hashbucket *dthb_next;	/* next on hash chain */
133	dtrace_probe_t *dthb_chain;		/* chain of probes */
134	int dthb_len;				/* number of probes here */
135} dtrace_hashbucket_t;
136
137typedef struct dtrace_hash {
138	dtrace_hashbucket_t **dth_tab;		/* hash table */
139	int dth_size;				/* size of hash table */
140	int dth_mask;				/* mask to index into table */
141	int dth_nbuckets;			/* total number of buckets */
142	uintptr_t dth_nextoffs;			/* offset of next in probe */
143	uintptr_t dth_prevoffs;			/* offset of prev in probe */
144	uintptr_t dth_stroffs;			/* offset of str in probe */
145} dtrace_hash_t;
146
147/*
148 * DTrace Enabling Control Blocks
149 *
150 * When a provider wishes to fire a probe, it calls into dtrace_probe(),
151 * passing the probe identifier as the first argument.  As described above,
152 * dtrace_probe() maps the identifier into a pointer to a dtrace_probe_t
153 * structure.  This structure contains information about the probe, and a
154 * pointer to the list of Enabling Control Blocks (ECBs).  Each ECB points to
155 * DTrace consumer state, and contains an optional predicate, and a list of
156 * actions.  (Shown schematically below.)  The ECB abstraction allows a single
157 * probe to be multiplexed across disjoint consumers, or across disjoint
158 * enablings of a single probe within one consumer.
159 *
160 *   Enabling Control Block
161 *        dtrace_ecb_t
162 * +------------------------+
163 * | dtrace_epid_t ---------+--------------> Enabled Probe ID (EPID)
164 * | dtrace_state_t * ------+--------------> State associated with this ECB
165 * | dtrace_predicate_t * --+---------+
166 * | dtrace_action_t * -----+----+    |
167 * | dtrace_ecb_t * ---+    |    |    |       Predicate (if any)
168 * +-------------------+----+    |    |       dtrace_predicate_t
169 *                     |         |    +---> +--------------------+
170 *                     |         |          | dtrace_difo_t * ---+----> DIFO
171 *                     |         |          +--------------------+
172 *                     |         |
173 *            Next ECB |         |           Action
174 *            (if any) |         |       dtrace_action_t
175 *                     :         +--> +-------------------+
176 *                     :              | dtrace_actkind_t -+------> kind
177 *                     v              | dtrace_difo_t * --+------> DIFO (if any)
178 *                                    | dtrace_recdesc_t -+------> record descr.
179 *                                    | dtrace_action_t * +------+
180 *                                    +-------------------+      |
181 *                                                               | Next action
182 *                               +-------------------------------+  (if any)
183 *                               |
184 *                               |           Action
185 *                               |       dtrace_action_t
186 *                               +--> +-------------------+
187 *                                    | dtrace_actkind_t -+------> kind
188 *                                    | dtrace_difo_t * --+------> DIFO (if any)
189 *                                    | dtrace_action_t * +------+
190 *                                    +-------------------+      |
191 *                                                               | Next action
192 *                               +-------------------------------+  (if any)
193 *                               |
194 *                               :
195 *                               v
196 *
197 *
198 * dtrace_probe() iterates over the ECB list.  If the ECB needs less space
199 * than is available in the principal buffer, the ECB is processed:  if the
200 * predicate is non-NULL, the DIF object is executed.  If the result is
201 * non-zero, the action list is processed, with each action being executed
202 * accordingly.  When the action list has been completely executed, processing
203 * advances to the next ECB. The ECB abstraction allows disjoint consumers
204 * to multiplex on single probes.
205 *
206 * Execution of the ECB results in consuming dte_size bytes in the buffer
207 * to record data.  During execution, dte_needed bytes must be available in
208 * the buffer.  This space is used for both recorded data and tuple data.
209 */
210struct dtrace_ecb {
211	dtrace_epid_t dte_epid;			/* enabled probe ID */
212	uint32_t dte_alignment;			/* required alignment */
213	size_t dte_needed;			/* space needed for execution */
214	size_t dte_size;			/* size of recorded payload */
215	dtrace_predicate_t *dte_predicate;	/* predicate, if any */
216	dtrace_action_t *dte_action;		/* actions, if any */
217	dtrace_ecb_t *dte_next;			/* next ECB on probe */
218	dtrace_state_t *dte_state;		/* pointer to state */
219	uint32_t dte_cond;			/* security condition */
220	dtrace_probe_t *dte_probe;		/* pointer to probe */
221	dtrace_action_t *dte_action_last;	/* last action on ECB */
222	uint64_t dte_uarg;			/* library argument */
223};
224
225struct dtrace_predicate {
226	dtrace_difo_t *dtp_difo;		/* DIF object */
227	dtrace_cacheid_t dtp_cacheid;		/* cache identifier */
228	int dtp_refcnt;				/* reference count */
229};
230
231struct dtrace_action {
232	dtrace_actkind_t dta_kind;		/* kind of action */
233	uint16_t dta_intuple;			/* boolean:  in aggregation */
234	uint32_t dta_refcnt;			/* reference count */
235	dtrace_difo_t *dta_difo;		/* pointer to DIFO */
236	dtrace_recdesc_t dta_rec;		/* record description */
237	dtrace_action_t *dta_prev;		/* previous action */
238	dtrace_action_t *dta_next;		/* next action */
239};
240
241typedef struct dtrace_aggregation {
242	dtrace_action_t dtag_action;		/* action; must be first */
243	dtrace_aggid_t dtag_id;			/* identifier */
244	dtrace_ecb_t *dtag_ecb;			/* corresponding ECB */
245	dtrace_action_t *dtag_first;		/* first action in tuple */
246	uint32_t dtag_base;			/* base of aggregation */
247	uint8_t dtag_hasarg;			/* boolean:  has argument */
248	uint64_t dtag_initial;			/* initial value */
249	void (*dtag_aggregate)(uint64_t *, uint64_t, uint64_t);
250} dtrace_aggregation_t;
251
252/*
253 * DTrace Buffers
254 *
255 * Principal buffers, aggregation buffers, and speculative buffers are all
256 * managed with the dtrace_buffer structure.  By default, this structure
257 * includes twin data buffers -- dtb_tomax and dtb_xamot -- that serve as the
258 * active and passive buffers, respectively.  For speculative buffers,
259 * dtb_xamot will be NULL; for "ring" and "fill" buffers, dtb_xamot will point
260 * to a scratch buffer.  For all buffer types, the dtrace_buffer structure is
261 * always allocated on a per-CPU basis; a single dtrace_buffer structure is
262 * never shared among CPUs.  (That is, there is never true sharing of the
263 * dtrace_buffer structure; to prevent false sharing of the structure, it must
264 * always be aligned to the coherence granularity -- generally 64 bytes.)
265 *
266 * One of the critical design decisions of DTrace is that a given ECB always
267 * stores the same quantity and type of data.  This is done to assure that the
268 * only metadata required for an ECB's traced data is the EPID.  That is, from
269 * the EPID, the consumer can determine the data layout.  (The data buffer
270 * layout is shown schematically below.)  By assuring that one can determine
271 * data layout from the EPID, the metadata stream can be separated from the
272 * data stream -- simplifying the data stream enormously.  The ECB always
273 * proceeds the recorded data as part of the dtrace_rechdr_t structure that
274 * includes the EPID and a high-resolution timestamp used for output ordering
275 * consistency.
276 *
277 *      base of data buffer --->  +--------+--------------------+--------+
278 *                                | rechdr | data               | rechdr |
279 *                                +--------+------+--------+----+--------+
280 *                                | data          | rechdr | data        |
281 *                                +---------------+--------+-------------+
282 *                                | data, cont.                          |
283 *                                +--------+--------------------+--------+
284 *                                | rechdr | data               |        |
285 *                                +--------+--------------------+        |
286 *                                |                ||                    |
287 *                                |                ||                    |
288 *                                |                \/                    |
289 *                                :                                      :
290 *                                .                                      .
291 *                                .                                      .
292 *                                .                                      .
293 *                                :                                      :
294 *                                |                                      |
295 *     limit of data buffer --->  +--------------------------------------+
296 *
297 * When evaluating an ECB, dtrace_probe() determines if the ECB's needs of the
298 * principal buffer (both scratch and payload) exceed the available space.  If
299 * the ECB's needs exceed available space (and if the principal buffer policy
300 * is the default "switch" policy), the ECB is dropped, the buffer's drop count
301 * is incremented, and processing advances to the next ECB.  If the ECB's needs
302 * can be met with the available space, the ECB is processed, but the offset in
303 * the principal buffer is only advanced if the ECB completes processing
304 * without error.
305 *
306 * When a buffer is to be switched (either because the buffer is the principal
307 * buffer with a "switch" policy or because it is an aggregation buffer), a
308 * cross call is issued to the CPU associated with the buffer.  In the cross
309 * call context, interrupts are disabled, and the active and the inactive
310 * buffers are atomically switched.  This involves switching the data pointers,
311 * copying the various state fields (offset, drops, errors, etc.) into their
312 * inactive equivalents, and clearing the state fields.  Because interrupts are
313 * disabled during this procedure, the switch is guaranteed to appear atomic to
314 * dtrace_probe().
315 *
316 * DTrace Ring Buffering
317 *
318 * To process a ring buffer correctly, one must know the oldest valid record.
319 * Processing starts at the oldest record in the buffer and continues until
320 * the end of the buffer is reached.  Processing then resumes starting with
321 * the record stored at offset 0 in the buffer, and continues until the
322 * youngest record is processed.  If trace records are of a fixed-length,
323 * determining the oldest record is trivial:
324 *
325 *   - If the ring buffer has not wrapped, the oldest record is the record
326 *     stored at offset 0.
327 *
328 *   - If the ring buffer has wrapped, the oldest record is the record stored
329 *     at the current offset.
330 *
331 * With variable length records, however, just knowing the current offset
332 * doesn't suffice for determining the oldest valid record:  assuming that one
333 * allows for arbitrary data, one has no way of searching forward from the
334 * current offset to find the oldest valid record.  (That is, one has no way
335 * of separating data from metadata.) It would be possible to simply refuse to
336 * process any data in the ring buffer between the current offset and the
337 * limit, but this leaves (potentially) an enormous amount of otherwise valid
338 * data unprocessed.
339 *
340 * To effect ring buffering, we track two offsets in the buffer:  the current
341 * offset and the _wrapped_ offset.  If a request is made to reserve some
342 * amount of data, and the buffer has wrapped, the wrapped offset is
343 * incremented until the wrapped offset minus the current offset is greater
344 * than or equal to the reserve request.  This is done by repeatedly looking
345 * up the ECB corresponding to the EPID at the current wrapped offset, and
346 * incrementing the wrapped offset by the size of the data payload
347 * corresponding to that ECB.  If this offset is greater than or equal to the
348 * limit of the data buffer, the wrapped offset is set to 0.  Thus, the
349 * current offset effectively "chases" the wrapped offset around the buffer.
350 * Schematically:
351 *
352 *      base of data buffer --->  +------+--------------------+------+
353 *                                | EPID | data               | EPID |
354 *                                +------+--------+------+----+------+
355 *                                | data          | EPID | data      |
356 *                                +---------------+------+-----------+
357 *                                | data, cont.                      |
358 *                                +------+---------------------------+
359 *                                | EPID | data                      |
360 *           current offset --->  +------+---------------------------+
361 *                                | invalid data                     |
362 *           wrapped offset --->  +------+--------------------+------+
363 *                                | EPID | data               | EPID |
364 *                                +------+--------+------+----+------+
365 *                                | data          | EPID | data      |
366 *                                +---------------+------+-----------+
367 *                                :                                  :
368 *                                .                                  .
369 *                                .        ... valid data ...        .
370 *                                .                                  .
371 *                                :                                  :
372 *                                +------+-------------+------+------+
373 *                                | EPID | data        | EPID | data |
374 *                                +------+------------++------+------+
375 *                                | data, cont.       | leftover     |
376 *     limit of data buffer --->  +-------------------+--------------+
377 *
378 * If the amount of requested buffer space exceeds the amount of space
379 * available between the current offset and the end of the buffer:
380 *
381 *  (1)  all words in the data buffer between the current offset and the limit
382 *       of the data buffer (marked "leftover", above) are set to
383 *       DTRACE_EPIDNONE
384 *
385 *  (2)  the wrapped offset is set to zero
386 *
387 *  (3)  the iteration process described above occurs until the wrapped offset
388 *       is greater than the amount of desired space.
389 *
390 * The wrapped offset is implemented by (re-)using the inactive offset.
391 * In a "switch" buffer policy, the inactive offset stores the offset in
392 * the inactive buffer; in a "ring" buffer policy, it stores the wrapped
393 * offset.
394 *
395 * DTrace Scratch Buffering
396 *
397 * Some ECBs may wish to allocate dynamically-sized temporary scratch memory.
398 * To accommodate such requests easily, scratch memory may be allocated in
399 * the buffer beyond the current offset plus the needed memory of the current
400 * ECB.  If there isn't sufficient room in the buffer for the requested amount
401 * of scratch space, the allocation fails and an error is generated.  Scratch
402 * memory is tracked in the dtrace_mstate_t and is automatically freed when
403 * the ECB ceases processing.  Note that ring buffers cannot allocate their
404 * scratch from the principal buffer -- lest they needlessly overwrite older,
405 * valid data.  Ring buffers therefore have their own dedicated scratch buffer
406 * from which scratch is allocated.
407 */
408#define	DTRACEBUF_RING		0x0001		/* bufpolicy set to "ring" */
409#define	DTRACEBUF_FILL		0x0002		/* bufpolicy set to "fill" */
410#define	DTRACEBUF_NOSWITCH	0x0004		/* do not switch buffer */
411#define	DTRACEBUF_WRAPPED	0x0008		/* ring buffer has wrapped */
412#define	DTRACEBUF_DROPPED	0x0010		/* drops occurred */
413#define	DTRACEBUF_ERROR		0x0020		/* errors occurred */
414#define	DTRACEBUF_FULL		0x0040		/* "fill" buffer is full */
415#define	DTRACEBUF_CONSUMED	0x0080		/* buffer has been consumed */
416#define	DTRACEBUF_INACTIVE	0x0100		/* buffer is not yet active */
417
418typedef struct dtrace_buffer {
419	uint64_t dtb_offset;			/* current offset in buffer */
420	uint64_t dtb_size;			/* size of buffer */
421	uint32_t dtb_flags;			/* flags */
422	uint32_t dtb_drops;			/* number of drops */
423	caddr_t dtb_tomax;			/* active buffer */
424	caddr_t dtb_xamot;			/* inactive buffer */
425	uint32_t dtb_xamot_flags;		/* inactive flags */
426	uint32_t dtb_xamot_drops;		/* drops in inactive buffer */
427	uint64_t dtb_xamot_offset;		/* offset in inactive buffer */
428	uint32_t dtb_errors;			/* number of errors */
429	uint32_t dtb_xamot_errors;		/* errors in inactive buffer */
430#ifndef _LP64
431	uint64_t dtb_pad1;			/* pad out to 64 bytes */
432#endif
433	uint64_t dtb_switched;			/* time of last switch */
434	uint64_t dtb_interval;			/* observed switch interval */
435	uint64_t dtb_pad2[6];			/* pad to avoid false sharing */
436} dtrace_buffer_t;
437
438/*
439 * DTrace Aggregation Buffers
440 *
441 * Aggregation buffers use much of the same mechanism as described above
442 * ("DTrace Buffers").  However, because an aggregation is fundamentally a
443 * hash, there exists dynamic metadata associated with an aggregation buffer
444 * that is not associated with other kinds of buffers.  This aggregation
445 * metadata is _only_ relevant for the in-kernel implementation of
446 * aggregations; it is not actually relevant to user-level consumers.  To do
447 * this, we allocate dynamic aggregation data (hash keys and hash buckets)
448 * starting below the _limit_ of the buffer, and we allocate data from the
449 * _base_ of the buffer.  When the aggregation buffer is copied out, _only_ the
450 * data is copied out; the metadata is simply discarded.  Schematically,
451 * aggregation buffers look like:
452 *
453 *      base of data buffer --->  +-------+------+-----------+-------+
454 *                                | aggid | key  | value     | aggid |
455 *                                +-------+------+-----------+-------+
456 *                                | key                              |
457 *                                +-------+-------+-----+------------+
458 *                                | value | aggid | key | value      |
459 *                                +-------+------++-----+------+-----+
460 *                                | aggid | key  | value       |     |
461 *                                +-------+------+-------------+     |
462 *                                |                ||                |
463 *                                |                ||                |
464 *                                |                \/                |
465 *                                :                                  :
466 *                                .                                  .
467 *                                .                                  .
468 *                                .                                  .
469 *                                :                                  :
470 *                                |                /\                |
471 *                                |                ||   +------------+
472 *                                |                ||   |            |
473 *                                +---------------------+            |
474 *                                | hash keys                        |
475 *                                | (dtrace_aggkey structures)       |
476 *                                |                                  |
477 *                                +----------------------------------+
478 *                                | hash buckets                     |
479 *                                | (dtrace_aggbuffer structure)     |
480 *                                |                                  |
481 *     limit of data buffer --->  +----------------------------------+
482 *
483 *
484 * As implied above, just as we assure that ECBs always store a constant
485 * amount of data, we assure that a given aggregation -- identified by its
486 * aggregation ID -- always stores data of a constant quantity and type.
487 * As with EPIDs, this allows the aggregation ID to serve as the metadata for a
488 * given record.
489 *
490 * Note that the size of the dtrace_aggkey structure must be sizeof (uintptr_t)
491 * aligned.  (If this the structure changes such that this becomes false, an
492 * assertion will fail in dtrace_aggregate().)
493 */
494typedef struct dtrace_aggkey {
495	uint32_t dtak_hashval;			/* hash value */
496	uint32_t dtak_action:4;			/* action -- 4 bits */
497	uint32_t dtak_size:28;			/* size -- 28 bits */
498	caddr_t dtak_data;			/* data pointer */
499	struct dtrace_aggkey *dtak_next;	/* next in hash chain */
500} dtrace_aggkey_t;
501
502typedef struct dtrace_aggbuffer {
503	uintptr_t dtagb_hashsize;		/* number of buckets */
504	uintptr_t dtagb_free;			/* free list of keys */
505	dtrace_aggkey_t **dtagb_hash;		/* hash table */
506} dtrace_aggbuffer_t;
507
508/*
509 * DTrace Speculations
510 *
511 * Speculations have a per-CPU buffer and a global state.  Once a speculation
512 * buffer has been comitted or discarded, it cannot be reused until all CPUs
513 * have taken the same action (commit or discard) on their respective
514 * speculative buffer.  However, because DTrace probes may execute in arbitrary
515 * context, other CPUs cannot simply be cross-called at probe firing time to
516 * perform the necessary commit or discard.  The speculation states thus
517 * optimize for the case that a speculative buffer is only active on one CPU at
518 * the time of a commit() or discard() -- for if this is the case, other CPUs
519 * need not take action, and the speculation is immediately available for
520 * reuse.  If the speculation is active on multiple CPUs, it must be
521 * asynchronously cleaned -- potentially leading to a higher rate of dirty
522 * speculative drops.  The speculation states are as follows:
523 *
524 *  DTRACESPEC_INACTIVE       <= Initial state; inactive speculation
525 *  DTRACESPEC_ACTIVE         <= Allocated, but not yet speculatively traced to
526 *  DTRACESPEC_ACTIVEONE      <= Speculatively traced to on one CPU
527 *  DTRACESPEC_ACTIVEMANY     <= Speculatively traced to on more than one CPU
528 *  DTRACESPEC_COMMITTING     <= Currently being commited on one CPU
529 *  DTRACESPEC_COMMITTINGMANY <= Currently being commited on many CPUs
530 *  DTRACESPEC_DISCARDING     <= Currently being discarded on many CPUs
531 *
532 * The state transition diagram is as follows:
533 *
534 *     +----------------------------------------------------------+
535 *     |                                                          |
536 *     |                      +------------+                      |
537 *     |  +-------------------| COMMITTING |<-----------------+   |
538 *     |  |                   +------------+                  |   |
539 *     |  | copied spec.            ^             commit() on |   | discard() on
540 *     |  | into principal          |              active CPU |   | active CPU
541 *     |  |                         | commit()                |   |
542 *     V  V                         |                         |   |
543 * +----------+                 +--------+                +-----------+
544 * | INACTIVE |---------------->| ACTIVE |--------------->| ACTIVEONE |
545 * +----------+  speculation()  +--------+  speculate()   +-----------+
546 *     ^  ^                         |                         |   |
547 *     |  |                         | discard()               |   |
548 *     |  | asynchronously          |            discard() on |   | speculate()
549 *     |  | cleaned                 V            inactive CPU |   | on inactive
550 *     |  |                   +------------+                  |   | CPU
551 *     |  +-------------------| DISCARDING |<-----------------+   |
552 *     |                      +------------+                      |
553 *     | asynchronously             ^                             |
554 *     | copied spec.               |       discard()             |
555 *     | into principal             +------------------------+    |
556 *     |                                                     |    V
557 *  +----------------+             commit()              +------------+
558 *  | COMMITTINGMANY |<----------------------------------| ACTIVEMANY |
559 *  +----------------+                                   +------------+
560 */
561typedef enum dtrace_speculation_state {
562	DTRACESPEC_INACTIVE = 0,
563	DTRACESPEC_ACTIVE,
564	DTRACESPEC_ACTIVEONE,
565	DTRACESPEC_ACTIVEMANY,
566	DTRACESPEC_COMMITTING,
567	DTRACESPEC_COMMITTINGMANY,
568	DTRACESPEC_DISCARDING
569} dtrace_speculation_state_t;
570
571typedef struct dtrace_speculation {
572	dtrace_speculation_state_t dtsp_state;	/* current speculation state */
573	int dtsp_cleaning;			/* non-zero if being cleaned */
574	dtrace_buffer_t *dtsp_buffer;		/* speculative buffer */
575} dtrace_speculation_t;
576
577/*
578 * DTrace Dynamic Variables
579 *
580 * The dynamic variable problem is obviously decomposed into two subproblems:
581 * allocating new dynamic storage, and freeing old dynamic storage.  The
582 * presence of the second problem makes the first much more complicated -- or
583 * rather, the absence of the second renders the first trivial.  This is the
584 * case with aggregations, for which there is effectively no deallocation of
585 * dynamic storage.  (Or more accurately, all dynamic storage is deallocated
586 * when a snapshot is taken of the aggregation.)  As DTrace dynamic variables
587 * allow for both dynamic allocation and dynamic deallocation, the
588 * implementation of dynamic variables is quite a bit more complicated than
589 * that of their aggregation kin.
590 *
591 * We observe that allocating new dynamic storage is tricky only because the
592 * size can vary -- the allocation problem is much easier if allocation sizes
593 * are uniform.  We further observe that in D, the size of dynamic variables is
594 * actually _not_ dynamic -- dynamic variable sizes may be determined by static
595 * analysis of DIF text.  (This is true even of putatively dynamically-sized
596 * objects like strings and stacks, the sizes of which are dictated by the
597 * "stringsize" and "stackframes" variables, respectively.)  We exploit this by
598 * performing this analysis on all DIF before enabling any probes.  For each
599 * dynamic load or store, we calculate the dynamically-allocated size plus the
600 * size of the dtrace_dynvar structure plus the storage required to key the
601 * data.  For all DIF, we take the largest value and dub it the _chunksize_.
602 * We then divide dynamic memory into two parts:  a hash table that is wide
603 * enough to have every chunk in its own bucket, and a larger region of equal
604 * chunksize units.  Whenever we wish to dynamically allocate a variable, we
605 * always allocate a single chunk of memory.  Depending on the uniformity of
606 * allocation, this will waste some amount of memory -- but it eliminates the
607 * non-determinism inherent in traditional heap fragmentation.
608 *
609 * Dynamic objects are allocated by storing a non-zero value to them; they are
610 * deallocated by storing a zero value to them.  Dynamic variables are
611 * complicated enormously by being shared between CPUs.  In particular,
612 * consider the following scenario:
613 *
614 *                 CPU A                                 CPU B
615 *  +---------------------------------+   +---------------------------------+
616 *  |                                 |   |                                 |
617 *  | allocates dynamic object a[123] |   |                                 |
618 *  | by storing the value 345 to it  |   |                                 |
619 *  |                               --------->                              |
620 *  |                                 |   | wishing to load from object     |
621 *  |                                 |   | a[123], performs lookup in      |
622 *  |                                 |   | dynamic variable space          |
623 *  |                               <---------                              |
624 *  | deallocates object a[123] by    |   |                                 |
625 *  | storing 0 to it                 |   |                                 |
626 *  |                                 |   |                                 |
627 *  | allocates dynamic object b[567] |   | performs load from a[123]       |
628 *  | by storing the value 789 to it  |   |                                 |
629 *  :                                 :   :                                 :
630 *  .                                 .   .                                 .
631 *
632 * This is obviously a race in the D program, but there are nonetheless only
633 * two valid values for CPU B's load from a[123]:  345 or 0.  Most importantly,
634 * CPU B may _not_ see the value 789 for a[123].
635 *
636 * There are essentially two ways to deal with this:
637 *
638 *  (1)  Explicitly spin-lock variables.  That is, if CPU B wishes to load
639 *       from a[123], it needs to lock a[123] and hold the lock for the
640 *       duration that it wishes to manipulate it.
641 *
642 *  (2)  Avoid reusing freed chunks until it is known that no CPU is referring
643 *       to them.
644 *
645 * The implementation of (1) is rife with complexity, because it requires the
646 * user of a dynamic variable to explicitly decree when they are done using it.
647 * Were all variables by value, this perhaps wouldn't be debilitating -- but
648 * dynamic variables of non-scalar types are tracked by reference.  That is, if
649 * a dynamic variable is, say, a string, and that variable is to be traced to,
650 * say, the principal buffer, the DIF emulation code returns to the main
651 * dtrace_probe() loop a pointer to the underlying storage, not the contents of
652 * the storage.  Further, code calling on DIF emulation would have to be aware
653 * that the DIF emulation has returned a reference to a dynamic variable that
654 * has been potentially locked.  The variable would have to be unlocked after
655 * the main dtrace_probe() loop is finished with the variable, and the main
656 * dtrace_probe() loop would have to be careful to not call any further DIF
657 * emulation while the variable is locked to avoid deadlock.  More generally,
658 * if one were to implement (1), DIF emulation code dealing with dynamic
659 * variables could only deal with one dynamic variable at a time (lest deadlock
660 * result).  To sum, (1) exports too much subtlety to the users of dynamic
661 * variables -- increasing maintenance burden and imposing serious constraints
662 * on future DTrace development.
663 *
664 * The implementation of (2) is also complex, but the complexity is more
665 * manageable.  We need to be sure that when a variable is deallocated, it is
666 * not placed on a traditional free list, but rather on a _dirty_ list.  Once a
667 * variable is on a dirty list, it cannot be found by CPUs performing a
668 * subsequent lookup of the variable -- but it may still be in use by other
669 * CPUs.  To assure that all CPUs that may be seeing the old variable have
670 * cleared out of probe context, a dtrace_sync() can be issued.  Once the
671 * dtrace_sync() has completed, it can be known that all CPUs are done
672 * manipulating the dynamic variable -- the dirty list can be atomically
673 * appended to the free list.  Unfortunately, there's a slight hiccup in this
674 * mechanism:  dtrace_sync() may not be issued from probe context.  The
675 * dtrace_sync() must be therefore issued asynchronously from non-probe
676 * context.  For this we rely on the DTrace cleaner, a cyclic that runs at the
677 * "cleanrate" frequency.  To ease this implementation, we define several chunk
678 * lists:
679 *
680 *   - Dirty.  Deallocated chunks, not yet cleaned.  Not available.
681 *
682 *   - Rinsing.  Formerly dirty chunks that are currently being asynchronously
683 *     cleaned.  Not available, but will be shortly.  Dynamic variable
684 *     allocation may not spin or block for availability, however.
685 *
686 *   - Clean.  Clean chunks, ready for allocation -- but not on the free list.
687 *
688 *   - Free.  Available for allocation.
689 *
690 * Moreover, to avoid absurd contention, _each_ of these lists is implemented
691 * on a per-CPU basis.  This is only for performance, not correctness; chunks
692 * may be allocated from another CPU's free list.  The algorithm for allocation
693 * then is this:
694 *
695 *   (1)  Attempt to atomically allocate from current CPU's free list.  If list
696 *        is non-empty and allocation is successful, allocation is complete.
697 *
698 *   (2)  If the clean list is non-empty, atomically move it to the free list,
699 *        and reattempt (1).
700 *
701 *   (3)  If the dynamic variable space is in the CLEAN state, look for free
702 *        and clean lists on other CPUs by setting the current CPU to the next
703 *        CPU, and reattempting (1).  If the next CPU is the current CPU (that
704 *        is, if all CPUs have been checked), atomically switch the state of
705 *        the dynamic variable space based on the following:
706 *
707 *        - If no free chunks were found and no dirty chunks were found,
708 *          atomically set the state to EMPTY.
709 *
710 *        - If dirty chunks were found, atomically set the state to DIRTY.
711 *
712 *        - If rinsing chunks were found, atomically set the state to RINSING.
713 *
714 *   (4)  Based on state of dynamic variable space state, increment appropriate
715 *        counter to indicate dynamic drops (if in EMPTY state) vs. dynamic
716 *        dirty drops (if in DIRTY state) vs. dynamic rinsing drops (if in
717 *        RINSING state).  Fail the allocation.
718 *
719 * The cleaning cyclic operates with the following algorithm:  for all CPUs
720 * with a non-empty dirty list, atomically move the dirty list to the rinsing
721 * list.  Perform a dtrace_sync().  For all CPUs with a non-empty rinsing list,
722 * atomically move the rinsing list to the clean list.  Perform another
723 * dtrace_sync().  By this point, all CPUs have seen the new clean list; the
724 * state of the dynamic variable space can be restored to CLEAN.
725 *
726 * There exist two final races that merit explanation.  The first is a simple
727 * allocation race:
728 *
729 *                 CPU A                                 CPU B
730 *  +---------------------------------+   +---------------------------------+
731 *  |                                 |   |                                 |
732 *  | allocates dynamic object a[123] |   | allocates dynamic object a[123] |
733 *  | by storing the value 345 to it  |   | by storing the value 567 to it  |
734 *  |                                 |   |                                 |
735 *  :                                 :   :                                 :
736 *  .                                 .   .                                 .
737 *
738 * Again, this is a race in the D program.  It can be resolved by having a[123]
739 * hold the value 345 or a[123] hold the value 567 -- but it must be true that
740 * a[123] have only _one_ of these values.  (That is, the racing CPUs may not
741 * put the same element twice on the same hash chain.)  This is resolved
742 * simply:  before the allocation is undertaken, the start of the new chunk's
743 * hash chain is noted.  Later, after the allocation is complete, the hash
744 * chain is atomically switched to point to the new element.  If this fails
745 * (because of either concurrent allocations or an allocation concurrent with a
746 * deletion), the newly allocated chunk is deallocated to the dirty list, and
747 * the whole process of looking up (and potentially allocating) the dynamic
748 * variable is reattempted.
749 *
750 * The final race is a simple deallocation race:
751 *
752 *                 CPU A                                 CPU B
753 *  +---------------------------------+   +---------------------------------+
754 *  |                                 |   |                                 |
755 *  | deallocates dynamic object      |   | deallocates dynamic object      |
756 *  | a[123] by storing the value 0   |   | a[123] by storing the value 0   |
757 *  | to it                           |   | to it                           |
758 *  |                                 |   |                                 |
759 *  :                                 :   :                                 :
760 *  .                                 .   .                                 .
761 *
762 * Once again, this is a race in the D program, but it is one that we must
763 * handle without corrupting the underlying data structures.  Because
764 * deallocations require the deletion of a chunk from the middle of a hash
765 * chain, we cannot use a single-word atomic operation to remove it.  For this,
766 * we add a spin lock to the hash buckets that is _only_ used for deallocations
767 * (allocation races are handled as above).  Further, this spin lock is _only_
768 * held for the duration of the delete; before control is returned to the DIF
769 * emulation code, the hash bucket is unlocked.
770 */
771typedef struct dtrace_key {
772	uint64_t dttk_value;			/* data value or data pointer */
773	uint64_t dttk_size;			/* 0 if by-val, >0 if by-ref */
774} dtrace_key_t;
775
776typedef struct dtrace_tuple {
777	uint32_t dtt_nkeys;			/* number of keys in tuple */
778	uint32_t dtt_pad;			/* padding */
779	dtrace_key_t dtt_key[1];		/* array of tuple keys */
780} dtrace_tuple_t;
781
782typedef struct dtrace_dynvar {
783	uint64_t dtdv_hashval;			/* hash value -- 0 if free */
784	struct dtrace_dynvar *dtdv_next;	/* next on list or hash chain */
785	void *dtdv_data;			/* pointer to data */
786	dtrace_tuple_t dtdv_tuple;		/* tuple key */
787} dtrace_dynvar_t;
788
789typedef enum dtrace_dynvar_op {
790	DTRACE_DYNVAR_ALLOC,
791	DTRACE_DYNVAR_NOALLOC,
792	DTRACE_DYNVAR_DEALLOC
793} dtrace_dynvar_op_t;
794
795typedef struct dtrace_dynhash {
796	dtrace_dynvar_t *dtdh_chain;		/* hash chain for this bucket */
797	uintptr_t dtdh_lock;			/* deallocation lock */
798#ifdef _LP64
799	uintptr_t dtdh_pad[6];			/* pad to avoid false sharing */
800#else
801	uintptr_t dtdh_pad[14];			/* pad to avoid false sharing */
802#endif
803} dtrace_dynhash_t;
804
805typedef struct dtrace_dstate_percpu {
806	dtrace_dynvar_t *dtdsc_free;		/* free list for this CPU */
807	dtrace_dynvar_t *dtdsc_dirty;		/* dirty list for this CPU */
808	dtrace_dynvar_t *dtdsc_rinsing;		/* rinsing list for this CPU */
809	dtrace_dynvar_t *dtdsc_clean;		/* clean list for this CPU */
810	uint64_t dtdsc_drops;			/* number of capacity drops */
811	uint64_t dtdsc_dirty_drops;		/* number of dirty drops */
812	uint64_t dtdsc_rinsing_drops;		/* number of rinsing drops */
813#ifdef _LP64
814	uint64_t dtdsc_pad;			/* pad to avoid false sharing */
815#else
816	uint64_t dtdsc_pad[2];			/* pad to avoid false sharing */
817#endif
818} dtrace_dstate_percpu_t;
819
820typedef enum dtrace_dstate_state {
821	DTRACE_DSTATE_CLEAN = 0,
822	DTRACE_DSTATE_EMPTY,
823	DTRACE_DSTATE_DIRTY,
824	DTRACE_DSTATE_RINSING
825} dtrace_dstate_state_t;
826
827typedef struct dtrace_dstate {
828	void *dtds_base;			/* base of dynamic var. space */
829	size_t dtds_size;			/* size of dynamic var. space */
830	size_t dtds_hashsize;			/* number of buckets in hash */
831	size_t dtds_chunksize;			/* size of each chunk */
832	dtrace_dynhash_t *dtds_hash;		/* pointer to hash table */
833	dtrace_dstate_state_t dtds_state;	/* current dynamic var. state */
834	dtrace_dstate_percpu_t *dtds_percpu;	/* per-CPU dyn. var. state */
835} dtrace_dstate_t;
836
837/*
838 * DTrace Variable State
839 *
840 * The DTrace variable state tracks user-defined variables in its dtrace_vstate
841 * structure.  Each DTrace consumer has exactly one dtrace_vstate structure,
842 * but some dtrace_vstate structures may exist without a corresponding DTrace
843 * consumer (see "DTrace Helpers", below).  As described in <sys/dtrace.h>,
844 * user-defined variables can have one of three scopes:
845 *
846 *  DIFV_SCOPE_GLOBAL  =>  global scope
847 *  DIFV_SCOPE_THREAD  =>  thread-local scope (i.e. "self->" variables)
848 *  DIFV_SCOPE_LOCAL   =>  clause-local scope (i.e. "this->" variables)
849 *
850 * The variable state tracks variables by both their scope and their allocation
851 * type:
852 *
853 *  - The dtvs_globals and dtvs_locals members each point to an array of
854 *    dtrace_statvar structures.  These structures contain both the variable
855 *    metadata (dtrace_difv structures) and the underlying storage for all
856 *    statically allocated variables, including statically allocated
857 *    DIFV_SCOPE_GLOBAL variables and all DIFV_SCOPE_LOCAL variables.
858 *
859 *  - The dtvs_tlocals member points to an array of dtrace_difv structures for
860 *    DIFV_SCOPE_THREAD variables.  As such, this array tracks _only_ the
861 *    variable metadata for DIFV_SCOPE_THREAD variables; the underlying storage
862 *    is allocated out of the dynamic variable space.
863 *
864 *  - The dtvs_dynvars member is the dynamic variable state associated with the
865 *    variable state.  The dynamic variable state (described in "DTrace Dynamic
866 *    Variables", above) tracks all DIFV_SCOPE_THREAD variables and all
867 *    dynamically-allocated DIFV_SCOPE_GLOBAL variables.
868 */
869typedef struct dtrace_statvar {
870	uint64_t dtsv_data;			/* data or pointer to it */
871	size_t dtsv_size;			/* size of pointed-to data */
872	int dtsv_refcnt;			/* reference count */
873	dtrace_difv_t dtsv_var;			/* variable metadata */
874} dtrace_statvar_t;
875
876typedef struct dtrace_vstate {
877	dtrace_state_t *dtvs_state;		/* back pointer to state */
878	dtrace_statvar_t **dtvs_globals;	/* statically-allocated glbls */
879	int dtvs_nglobals;			/* number of globals */
880	dtrace_difv_t *dtvs_tlocals;		/* thread-local metadata */
881	int dtvs_ntlocals;			/* number of thread-locals */
882	dtrace_statvar_t **dtvs_locals;		/* clause-local data */
883	int dtvs_nlocals;			/* number of clause-locals */
884	dtrace_dstate_t dtvs_dynvars;		/* dynamic variable state */
885} dtrace_vstate_t;
886
887/*
888 * DTrace Machine State
889 *
890 * In the process of processing a fired probe, DTrace needs to track and/or
891 * cache some per-CPU state associated with that particular firing.  This is
892 * state that is always discarded after the probe firing has completed, and
893 * much of it is not specific to any DTrace consumer, remaining valid across
894 * all ECBs.  This state is tracked in the dtrace_mstate structure.
895 */
896#define	DTRACE_MSTATE_ARGS		0x00000001
897#define	DTRACE_MSTATE_PROBE		0x00000002
898#define	DTRACE_MSTATE_EPID		0x00000004
899#define	DTRACE_MSTATE_TIMESTAMP		0x00000008
900#define	DTRACE_MSTATE_STACKDEPTH	0x00000010
901#define	DTRACE_MSTATE_CALLER		0x00000020
902#define	DTRACE_MSTATE_IPL		0x00000040
903#define	DTRACE_MSTATE_FLTOFFS		0x00000080
904#define	DTRACE_MSTATE_WALLTIMESTAMP	0x00000100
905#define	DTRACE_MSTATE_USTACKDEPTH	0x00000200
906#define	DTRACE_MSTATE_UCALLER		0x00000400
907
908typedef struct dtrace_mstate {
909	uintptr_t dtms_scratch_base;		/* base of scratch space */
910	uintptr_t dtms_scratch_ptr;		/* current scratch pointer */
911	size_t dtms_scratch_size;		/* scratch size */
912	uint32_t dtms_present;			/* variables that are present */
913	uint64_t dtms_arg[5];			/* cached arguments */
914	dtrace_epid_t dtms_epid;		/* current EPID */
915	uint64_t dtms_timestamp;		/* cached timestamp */
916	hrtime_t dtms_walltimestamp;		/* cached wall timestamp */
917	int dtms_stackdepth;			/* cached stackdepth */
918	int dtms_ustackdepth;			/* cached ustackdepth */
919	struct dtrace_probe *dtms_probe;	/* current probe */
920	uintptr_t dtms_caller;			/* cached caller */
921	uint64_t dtms_ucaller;			/* cached user-level caller */
922	int dtms_ipl;				/* cached interrupt pri lev */
923	int dtms_fltoffs;			/* faulting DIFO offset */
924	uintptr_t dtms_strtok;			/* saved strtok() pointer */
925	uintptr_t dtms_strtok_limit;		/* upper bound of strtok ptr */
926	uint32_t dtms_access;			/* memory access rights */
927	dtrace_difo_t *dtms_difo;		/* current dif object */
928	file_t *dtms_getf;			/* cached rval of getf() */
929} dtrace_mstate_t;
930
931#define	DTRACE_COND_OWNER	0x1
932#define	DTRACE_COND_USERMODE	0x2
933#define	DTRACE_COND_ZONEOWNER	0x4
934
935#define	DTRACE_PROBEKEY_MAXDEPTH	8	/* max glob recursion depth */
936
937/*
938 * Access flag used by dtrace_mstate.dtms_access.
939 */
940#define	DTRACE_ACCESS_KERNEL	0x1		/* the priv to read kmem */
941#define	DTRACE_ACCESS_PROC	0x2		/* the priv for proc state */
942#define	DTRACE_ACCESS_ARGS	0x4		/* the priv to examine args */
943
944/*
945 * DTrace Activity
946 *
947 * Each DTrace consumer is in one of several states, which (for purposes of
948 * avoiding yet-another overloading of the noun "state") we call the current
949 * _activity_.  The activity transitions on dtrace_go() (from DTRACIOCGO), on
950 * dtrace_stop() (from DTRACIOCSTOP) and on the exit() action.  Activities may
951 * only transition in one direction; the activity transition diagram is a
952 * directed acyclic graph.  The activity transition diagram is as follows:
953 *
954 *
955 * +----------+                   +--------+                   +--------+
956 * | INACTIVE |------------------>| WARMUP |------------------>| ACTIVE |
957 * +----------+   dtrace_go(),    +--------+   dtrace_go(),    +--------+
958 *                before BEGIN        |        after BEGIN       |  |  |
959 *                                    |                          |  |  |
960 *                      exit() action |                          |  |  |
961 *                     from BEGIN ECB |                          |  |  |
962 *                                    |                          |  |  |
963 *                                    v                          |  |  |
964 *                               +----------+     exit() action  |  |  |
965 * +-----------------------------| DRAINING |<-------------------+  |  |
966 * |                             +----------+                       |  |
967 * |                                  |                             |  |
968 * |                   dtrace_stop(), |                             |  |
969 * |                     before END   |                             |  |
970 * |                                  |                             |  |
971 * |                                  v                             |  |
972 * | +---------+                 +----------+                       |  |
973 * | | STOPPED |<----------------| COOLDOWN |<----------------------+  |
974 * | +---------+  dtrace_stop(), +----------+     dtrace_stop(),       |
975 * |                after END                       before END         |
976 * |                                                                   |
977 * |                              +--------+                           |
978 * +----------------------------->| KILLED |<--------------------------+
979 *       deadman timeout or       +--------+     deadman timeout or
980 *        killed consumer                         killed consumer
981 *
982 * Note that once a DTrace consumer has stopped tracing, there is no way to
983 * restart it; if a DTrace consumer wishes to restart tracing, it must reopen
984 * the DTrace pseudodevice.
985 */
986typedef enum dtrace_activity {
987	DTRACE_ACTIVITY_INACTIVE = 0,		/* not yet running */
988	DTRACE_ACTIVITY_WARMUP,			/* while starting */
989	DTRACE_ACTIVITY_ACTIVE,			/* running */
990	DTRACE_ACTIVITY_DRAINING,		/* before stopping */
991	DTRACE_ACTIVITY_COOLDOWN,		/* while stopping */
992	DTRACE_ACTIVITY_STOPPED,		/* after stopping */
993	DTRACE_ACTIVITY_KILLED			/* killed */
994} dtrace_activity_t;
995
996/*
997 * DTrace Helper Implementation
998 *
999 * A description of the helper architecture may be found in <sys/dtrace.h>.
1000 * Each process contains a pointer to its helpers in its p_dtrace_helpers
1001 * member.  This is a pointer to a dtrace_helpers structure, which contains an
1002 * array of pointers to dtrace_helper structures, helper variable state (shared
1003 * among a process's helpers) and a generation count.  (The generation count is
1004 * used to provide an identifier when a helper is added so that it may be
1005 * subsequently removed.)  The dtrace_helper structure is self-explanatory,
1006 * containing pointers to the objects needed to execute the helper.  Note that
1007 * helpers are _duplicated_ across fork(2), and destroyed on exec(2).  No more
1008 * than dtrace_helpers_max are allowed per-process.
1009 */
1010#define	DTRACE_HELPER_ACTION_USTACK	0
1011#define	DTRACE_NHELPER_ACTIONS		1
1012
1013typedef struct dtrace_helper_action {
1014	int dtha_generation;			/* helper action generation */
1015	int dtha_nactions;			/* number of actions */
1016	dtrace_difo_t *dtha_predicate;		/* helper action predicate */
1017	dtrace_difo_t **dtha_actions;		/* array of actions */
1018	struct dtrace_helper_action *dtha_next;	/* next helper action */
1019} dtrace_helper_action_t;
1020
1021typedef struct dtrace_helper_provider {
1022	int dthp_generation;			/* helper provider generation */
1023	uint32_t dthp_ref;			/* reference count */
1024	dof_helper_t dthp_prov;			/* DOF w/ provider and probes */
1025} dtrace_helper_provider_t;
1026
1027typedef struct dtrace_helpers {
1028	dtrace_helper_action_t **dthps_actions;	/* array of helper actions */
1029	dtrace_vstate_t dthps_vstate;		/* helper action var. state */
1030	dtrace_helper_provider_t **dthps_provs;	/* array of providers */
1031	uint_t dthps_nprovs;			/* count of providers */
1032	uint_t dthps_maxprovs;			/* provider array size */
1033	int dthps_generation;			/* current generation */
1034	pid_t dthps_pid;			/* pid of associated proc */
1035	int dthps_deferred;			/* helper in deferred list */
1036	struct dtrace_helpers *dthps_next;	/* next pointer */
1037	struct dtrace_helpers *dthps_prev;	/* prev pointer */
1038} dtrace_helpers_t;
1039
1040/*
1041 * DTrace Helper Action Tracing
1042 *
1043 * Debugging helper actions can be arduous.  To ease the development and
1044 * debugging of helpers, DTrace contains a tracing-framework-within-a-tracing-
1045 * framework: helper tracing.  If dtrace_helptrace_enabled is non-zero (which
1046 * it is by default on DEBUG kernels), all helper activity will be traced to a
1047 * global, in-kernel ring buffer.  Each entry includes a pointer to the specific
1048 * helper, the location within the helper, and a trace of all local variables.
1049 * The ring buffer may be displayed in a human-readable format with the
1050 * ::dtrace_helptrace mdb(1) dcmd.
1051 */
1052#define	DTRACE_HELPTRACE_NEXT	(-1)
1053#define	DTRACE_HELPTRACE_DONE	(-2)
1054#define	DTRACE_HELPTRACE_ERR	(-3)
1055
1056typedef struct dtrace_helptrace {
1057	dtrace_helper_action_t	*dtht_helper;	/* helper action */
1058	int dtht_where;				/* where in helper action */
1059	int dtht_nlocals;			/* number of locals */
1060	int dtht_fault;				/* type of fault (if any) */
1061	int dtht_fltoffs;			/* DIF offset */
1062	uint64_t dtht_illval;			/* faulting value */
1063	uint64_t dtht_locals[1];		/* local variables */
1064} dtrace_helptrace_t;
1065
1066/*
1067 * DTrace Credentials
1068 *
1069 * In probe context, we have limited flexibility to examine the credentials
1070 * of the DTrace consumer that created a particular enabling.  We use
1071 * the Least Privilege interfaces to cache the consumer's cred pointer and
1072 * some facts about that credential in a dtrace_cred_t structure. These
1073 * can limit the consumer's breadth of visibility and what actions the
1074 * consumer may take.
1075 */
1076#define	DTRACE_CRV_ALLPROC		0x01
1077#define	DTRACE_CRV_KERNEL		0x02
1078#define	DTRACE_CRV_ALLZONE		0x04
1079
1080#define	DTRACE_CRV_ALL		(DTRACE_CRV_ALLPROC | DTRACE_CRV_KERNEL | \
1081	DTRACE_CRV_ALLZONE)
1082
1083#define	DTRACE_CRA_PROC				0x0001
1084#define	DTRACE_CRA_PROC_CONTROL			0x0002
1085#define	DTRACE_CRA_PROC_DESTRUCTIVE_ALLUSER	0x0004
1086#define	DTRACE_CRA_PROC_DESTRUCTIVE_ALLZONE	0x0008
1087#define	DTRACE_CRA_PROC_DESTRUCTIVE_CREDCHG	0x0010
1088#define	DTRACE_CRA_KERNEL			0x0020
1089#define	DTRACE_CRA_KERNEL_DESTRUCTIVE		0x0040
1090
1091#define	DTRACE_CRA_ALL		(DTRACE_CRA_PROC | \
1092	DTRACE_CRA_PROC_CONTROL | \
1093	DTRACE_CRA_PROC_DESTRUCTIVE_ALLUSER | \
1094	DTRACE_CRA_PROC_DESTRUCTIVE_ALLZONE | \
1095	DTRACE_CRA_PROC_DESTRUCTIVE_CREDCHG | \
1096	DTRACE_CRA_KERNEL | \
1097	DTRACE_CRA_KERNEL_DESTRUCTIVE)
1098
1099typedef struct dtrace_cred {
1100	cred_t			*dcr_cred;
1101	uint8_t			dcr_destructive;
1102	uint8_t			dcr_visible;
1103	uint16_t		dcr_action;
1104} dtrace_cred_t;
1105
1106/*
1107 * DTrace Consumer State
1108 *
1109 * Each DTrace consumer has an associated dtrace_state structure that contains
1110 * its in-kernel DTrace state -- including options, credentials, statistics and
1111 * pointers to ECBs, buffers, speculations and formats.  A dtrace_state
1112 * structure is also allocated for anonymous enablings.  When anonymous state
1113 * is grabbed, the grabbing consumers dts_anon pointer is set to the grabbed
1114 * dtrace_state structure.
1115 */
1116struct dtrace_state {
1117	dev_t dts_dev;				/* device */
1118	int dts_necbs;				/* total number of ECBs */
1119	dtrace_ecb_t **dts_ecbs;		/* array of ECBs */
1120	dtrace_epid_t dts_epid;			/* next EPID to allocate */
1121	size_t dts_needed;			/* greatest needed space */
1122	struct dtrace_state *dts_anon;		/* anon. state, if grabbed */
1123	dtrace_activity_t dts_activity;		/* current activity */
1124	dtrace_vstate_t dts_vstate;		/* variable state */
1125	dtrace_buffer_t *dts_buffer;		/* principal buffer */
1126	dtrace_buffer_t *dts_aggbuffer;		/* aggregation buffer */
1127	dtrace_speculation_t *dts_speculations;	/* speculation array */
1128	int dts_nspeculations;			/* number of speculations */
1129	int dts_naggregations;			/* number of aggregations */
1130	dtrace_aggregation_t **dts_aggregations; /* aggregation array */
1131	vmem_t *dts_aggid_arena;		/* arena for aggregation IDs */
1132	uint64_t dts_errors;			/* total number of errors */
1133	uint32_t dts_speculations_busy;		/* number of spec. busy */
1134	uint32_t dts_speculations_unavail;	/* number of spec unavail */
1135	uint32_t dts_stkstroverflows;		/* stack string tab overflows */
1136	uint32_t dts_dblerrors;			/* errors in ERROR probes */
1137	uint32_t dts_reserve;			/* space reserved for END */
1138	hrtime_t dts_laststatus;		/* time of last status */
1139	cyclic_id_t dts_cleaner;		/* cleaning cyclic */
1140	cyclic_id_t dts_deadman;		/* deadman cyclic */
1141	hrtime_t dts_alive;			/* time last alive */
1142	char dts_speculates;			/* boolean: has speculations */
1143	char dts_destructive;			/* boolean: has dest. actions */
1144	int dts_nformats;			/* number of formats */
1145	char **dts_formats;			/* format string array */
1146	dtrace_optval_t dts_options[DTRACEOPT_MAX]; /* options */
1147	dtrace_cred_t dts_cred;			/* credentials */
1148	size_t dts_nretained;			/* number of retained enabs */
1149	int dts_getf;				/* number of getf() calls */
1150};
1151
1152struct dtrace_provider {
1153	dtrace_pattr_t dtpv_attr;		/* provider attributes */
1154	dtrace_ppriv_t dtpv_priv;		/* provider privileges */
1155	dtrace_pops_t dtpv_pops;		/* provider operations */
1156	char *dtpv_name;			/* provider name */
1157	void *dtpv_arg;				/* provider argument */
1158	hrtime_t dtpv_defunct;			/* when made defunct */
1159	struct dtrace_provider *dtpv_next;	/* next provider */
1160};
1161
1162struct dtrace_meta {
1163	dtrace_mops_t dtm_mops;			/* meta provider operations */
1164	char *dtm_name;				/* meta provider name */
1165	void *dtm_arg;				/* meta provider user arg */
1166	uint64_t dtm_count;			/* no. of associated provs. */
1167};
1168
1169/*
1170 * DTrace Enablings
1171 *
1172 * A dtrace_enabling structure is used to track a collection of ECB
1173 * descriptions -- before they have been turned into actual ECBs.  This is
1174 * created as a result of DOF processing, and is generally used to generate
1175 * ECBs immediately thereafter.  However, enablings are also generally
1176 * retained should the probes they describe be created at a later time; as
1177 * each new module or provider registers with the framework, the retained
1178 * enablings are reevaluated, with any new match resulting in new ECBs.  To
1179 * prevent probes from being matched more than once, the enabling tracks the
1180 * last probe generation matched, and only matches probes from subsequent
1181 * generations.
1182 */
1183typedef struct dtrace_enabling {
1184	dtrace_ecbdesc_t **dten_desc;		/* all ECB descriptions */
1185	int dten_ndesc;				/* number of ECB descriptions */
1186	int dten_maxdesc;			/* size of ECB array */
1187	dtrace_vstate_t *dten_vstate;		/* associated variable state */
1188	dtrace_genid_t dten_probegen;		/* matched probe generation */
1189	dtrace_ecbdesc_t *dten_current;		/* current ECB description */
1190	int dten_error;				/* current error value */
1191	int dten_primed;			/* boolean: set if primed */
1192	struct dtrace_enabling *dten_prev;	/* previous enabling */
1193	struct dtrace_enabling *dten_next;	/* next enabling */
1194} dtrace_enabling_t;
1195
1196/*
1197 * DTrace Anonymous Enablings
1198 *
1199 * Anonymous enablings are DTrace enablings that are not associated with a
1200 * controlling process, but rather derive their enabling from DOF stored as
1201 * properties in the dtrace.conf file.  If there is an anonymous enabling, a
1202 * DTrace consumer state and enabling are created on attach.  The state may be
1203 * subsequently grabbed by the first consumer specifying the "grabanon"
1204 * option.  As long as an anonymous DTrace enabling exists, dtrace(7D) will
1205 * refuse to unload.
1206 */
1207typedef struct dtrace_anon {
1208	dtrace_state_t *dta_state;		/* DTrace consumer state */
1209	dtrace_enabling_t *dta_enabling;	/* pointer to enabling */
1210	processorid_t dta_beganon;		/* which CPU BEGIN ran on */
1211} dtrace_anon_t;
1212
1213/*
1214 * DTrace Error Debugging
1215 */
1216#ifdef DEBUG
1217#define	DTRACE_ERRDEBUG
1218#endif
1219
1220#ifdef DTRACE_ERRDEBUG
1221
1222typedef struct dtrace_errhash {
1223	const char	*dter_msg;	/* error message */
1224	int		dter_count;	/* number of times seen */
1225} dtrace_errhash_t;
1226
1227#define	DTRACE_ERRHASHSZ	256	/* must be > number of err msgs */
1228
1229#endif	/* DTRACE_ERRDEBUG */
1230
1231/*
1232 * DTrace Toxic Ranges
1233 *
1234 * DTrace supports safe loads from probe context; if the address turns out to
1235 * be invalid, a bit will be set by the kernel indicating that DTrace
1236 * encountered a memory error, and DTrace will propagate the error to the user
1237 * accordingly.  However, there may exist some regions of memory in which an
1238 * arbitrary load can change system state, and from which it is impossible to
1239 * recover from such a load after it has been attempted.  Examples of this may
1240 * include memory in which programmable I/O registers are mapped (for which a
1241 * read may have some implications for the device) or (in the specific case of
1242 * UltraSPARC-I and -II) the virtual address hole.  The platform is required
1243 * to make DTrace aware of these toxic ranges; DTrace will then check that
1244 * target addresses are not in a toxic range before attempting to issue a
1245 * safe load.
1246 */
1247typedef struct dtrace_toxrange {
1248	uintptr_t	dtt_base;		/* base of toxic range */
1249	uintptr_t	dtt_limit;		/* limit of toxic range */
1250} dtrace_toxrange_t;
1251
1252extern uint64_t dtrace_getarg(int, int);
1253extern greg_t dtrace_getfp(void);
1254extern int dtrace_getipl(void);
1255extern uintptr_t dtrace_caller(int);
1256extern uint32_t dtrace_cas32(uint32_t *, uint32_t, uint32_t);
1257extern void *dtrace_casptr(void *, void *, void *);
1258extern void dtrace_copyin(uintptr_t, uintptr_t, size_t, volatile uint16_t *);
1259extern void dtrace_copyinstr(uintptr_t, uintptr_t, size_t, volatile uint16_t *);
1260extern void dtrace_copyout(uintptr_t, uintptr_t, size_t, volatile uint16_t *);
1261extern void dtrace_copyoutstr(uintptr_t, uintptr_t, size_t,
1262    volatile uint16_t *);
1263extern void dtrace_getpcstack(pc_t *, int, int, uint32_t *);
1264extern ulong_t dtrace_getreg(struct regs *, uint_t);
1265extern void dtrace_setreg(struct regs *, uint_t, ulong_t);
1266extern uint64_t dtrace_getvmreg(uint_t, volatile uint16_t *);
1267extern int dtrace_getstackdepth(int);
1268extern void dtrace_getupcstack(uint64_t *, int);
1269extern void dtrace_getufpstack(uint64_t *, uint64_t *, int);
1270extern int dtrace_getustackdepth(void);
1271extern uintptr_t dtrace_fulword(void *);
1272extern uint8_t dtrace_fuword8(void *);
1273extern uint16_t dtrace_fuword16(void *);
1274extern uint32_t dtrace_fuword32(void *);
1275extern uint64_t dtrace_fuword64(void *);
1276extern void dtrace_probe_error(dtrace_state_t *, dtrace_epid_t, int, int,
1277    int, uintptr_t);
1278extern int dtrace_assfail(const char *, const char *, int);
1279extern int dtrace_attached(void);
1280extern hrtime_t dtrace_gethrestime();
1281
1282#ifdef __sparc
1283extern void dtrace_flush_windows(void);
1284extern void dtrace_flush_user_windows(void);
1285extern uint_t dtrace_getotherwin(void);
1286extern uint_t dtrace_getfprs(void);
1287#else
1288extern void dtrace_copy(uintptr_t, uintptr_t, size_t);
1289extern void dtrace_copystr(uintptr_t, uintptr_t, size_t, volatile uint16_t *);
1290#endif
1291
1292/*
1293 * DTrace Assertions
1294 *
1295 * DTrace calls ASSERT and VERIFY from probe context.  To assure that a failed
1296 * ASSERT or VERIFY does not induce a markedly more catastrophic failure (e.g.,
1297 * one from which a dump cannot be gleaned), DTrace must define its own ASSERT
1298 * and VERIFY macros to be ones that may safely be called from probe context.
1299 * This header file must thus be included by any DTrace component that calls
1300 * ASSERT and/or VERIFY from probe context, and _only_ by those components.
1301 * (The only exception to this is kernel debugging infrastructure at user-level
1302 * that doesn't depend on calling ASSERT.)
1303 */
1304#undef ASSERT
1305#undef VERIFY
1306#define	VERIFY(EX)	((void)((EX) || \
1307			dtrace_assfail(#EX, __FILE__, __LINE__)))
1308#ifdef DEBUG
1309#define	ASSERT(EX)	((void)((EX) || \
1310			dtrace_assfail(#EX, __FILE__, __LINE__)))
1311#else
1312#define	ASSERT(X)	((void)0)
1313#endif
1314
1315#ifdef	__cplusplus
1316}
1317#endif
1318
1319#endif /* _SYS_DTRACE_IMPL_H */
1320