4 * The contents of this file are subject to the terms of the
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25 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
26 * Use is subject to license terms.
30 * Copyright 2016 Joyent, Inc.
31 * Copyright (c) 2012 by Delphix. All rights reserved.
34 #ifndef _SYS_DTRACE_IMPL_H
35 #define _SYS_DTRACE_IMPL_H
42 * DTrace Dynamic Tracing Software: Kernel Implementation Interfaces
44 * Note: The contents of this file are private to the implementation of the
45 * Solaris system and DTrace subsystem and are subject to change at any time
46 * without notice. Applications and drivers using these interfaces will fail
47 * to run on future releases. These interfaces should not be used for any
48 * purpose except those expressly outlined in dtrace(7D) and libdtrace(3LIB).
49 * Please refer to the "Solaris Dynamic Tracing Guide" for more information.
52 #include <sys/dtrace.h>
57 typedef uint32_t pc_t;
59 typedef uintptr_t pc_t;
61 typedef u_long greg_t;
65 * DTrace Implementation Constants and Typedefs
67 #define DTRACE_MAXPROPLEN 128
68 #define DTRACE_DYNVAR_CHUNKSIZE 256
72 #endif /* __FreeBSD__ */
76 struct dtrace_predicate;
78 struct dtrace_provider;
81 typedef struct dtrace_probe dtrace_probe_t;
82 typedef struct dtrace_ecb dtrace_ecb_t;
83 typedef struct dtrace_predicate dtrace_predicate_t;
84 typedef struct dtrace_action dtrace_action_t;
85 typedef struct dtrace_provider dtrace_provider_t;
86 typedef struct dtrace_meta dtrace_meta_t;
87 typedef struct dtrace_state dtrace_state_t;
88 typedef uint32_t dtrace_optid_t;
89 typedef uint32_t dtrace_specid_t;
90 typedef uint64_t dtrace_genid_t;
95 * The probe is the fundamental unit of the DTrace architecture. Probes are
96 * created by DTrace providers, and managed by the DTrace framework. A probe
97 * is identified by a unique <provider, module, function, name> tuple, and has
98 * a unique probe identifier assigned to it. (Some probes are not associated
99 * with a specific point in text; these are called _unanchored probes_ and have
100 * no module or function associated with them.) Probes are represented as a
101 * dtrace_probe structure. To allow quick lookups based on each element of the
102 * probe tuple, probes are hashed by each of provider, module, function and
103 * name. (If a lookup is performed based on a regular expression, a
104 * dtrace_probekey is prepared, and a linear search is performed.) Each probe
105 * is additionally pointed to by a linear array indexed by its identifier. The
106 * identifier is the provider's mechanism for indicating to the DTrace
107 * framework that a probe has fired: the identifier is passed as the first
108 * argument to dtrace_probe(), where it is then mapped into the corresponding
109 * dtrace_probe structure. From the dtrace_probe structure, dtrace_probe() can
110 * iterate over the probe's list of enabling control blocks; see "DTrace
111 * Enabling Control Blocks", below.)
113 struct dtrace_probe {
114 dtrace_id_t dtpr_id; /* probe identifier */
115 dtrace_ecb_t *dtpr_ecb; /* ECB list; see below */
116 dtrace_ecb_t *dtpr_ecb_last; /* last ECB in list */
117 void *dtpr_arg; /* provider argument */
118 dtrace_cacheid_t dtpr_predcache; /* predicate cache ID */
119 int dtpr_aframes; /* artificial frames */
120 dtrace_provider_t *dtpr_provider; /* pointer to provider */
121 char *dtpr_mod; /* probe's module name */
122 char *dtpr_func; /* probe's function name */
123 char *dtpr_name; /* probe's name */
124 dtrace_probe_t *dtpr_nextmod; /* next in module hash */
125 dtrace_probe_t *dtpr_prevmod; /* previous in module hash */
126 dtrace_probe_t *dtpr_nextfunc; /* next in function hash */
127 dtrace_probe_t *dtpr_prevfunc; /* previous in function hash */
128 dtrace_probe_t *dtpr_nextname; /* next in name hash */
129 dtrace_probe_t *dtpr_prevname; /* previous in name hash */
130 dtrace_genid_t dtpr_gen; /* probe generation ID */
133 typedef int dtrace_probekey_f(const char *, const char *, int);
135 typedef struct dtrace_probekey {
136 char *dtpk_prov; /* provider name to match */
137 dtrace_probekey_f *dtpk_pmatch; /* provider matching function */
138 char *dtpk_mod; /* module name to match */
139 dtrace_probekey_f *dtpk_mmatch; /* module matching function */
140 char *dtpk_func; /* func name to match */
141 dtrace_probekey_f *dtpk_fmatch; /* func matching function */
142 char *dtpk_name; /* name to match */
143 dtrace_probekey_f *dtpk_nmatch; /* name matching function */
144 dtrace_id_t dtpk_id; /* identifier to match */
147 typedef struct dtrace_hashbucket {
148 struct dtrace_hashbucket *dthb_next; /* next on hash chain */
149 dtrace_probe_t *dthb_chain; /* chain of probes */
150 int dthb_len; /* number of probes here */
151 } dtrace_hashbucket_t;
153 typedef struct dtrace_hash {
154 dtrace_hashbucket_t **dth_tab; /* hash table */
155 int dth_size; /* size of hash table */
156 int dth_mask; /* mask to index into table */
157 int dth_nbuckets; /* total number of buckets */
158 uintptr_t dth_nextoffs; /* offset of next in probe */
159 uintptr_t dth_prevoffs; /* offset of prev in probe */
160 uintptr_t dth_stroffs; /* offset of str in probe */
164 * DTrace Enabling Control Blocks
166 * When a provider wishes to fire a probe, it calls into dtrace_probe(),
167 * passing the probe identifier as the first argument. As described above,
168 * dtrace_probe() maps the identifier into a pointer to a dtrace_probe_t
169 * structure. This structure contains information about the probe, and a
170 * pointer to the list of Enabling Control Blocks (ECBs). Each ECB points to
171 * DTrace consumer state, and contains an optional predicate, and a list of
172 * actions. (Shown schematically below.) The ECB abstraction allows a single
173 * probe to be multiplexed across disjoint consumers, or across disjoint
174 * enablings of a single probe within one consumer.
176 * Enabling Control Block
178 * +------------------------+
179 * | dtrace_epid_t ---------+--------------> Enabled Probe ID (EPID)
180 * | dtrace_state_t * ------+--------------> State associated with this ECB
181 * | dtrace_predicate_t * --+---------+
182 * | dtrace_action_t * -----+----+ |
183 * | dtrace_ecb_t * ---+ | | | Predicate (if any)
184 * +-------------------+----+ | | dtrace_predicate_t
185 * | | +---> +--------------------+
186 * | | | dtrace_difo_t * ---+----> DIFO
187 * | | +--------------------+
189 * Next ECB | | Action
190 * (if any) | | dtrace_action_t
191 * : +--> +-------------------+
192 * : | dtrace_actkind_t -+------> kind
193 * v | dtrace_difo_t * --+------> DIFO (if any)
194 * | dtrace_recdesc_t -+------> record descr.
195 * | dtrace_action_t * +------+
196 * +-------------------+ |
198 * +-------------------------------+ (if any)
202 * +--> +-------------------+
203 * | dtrace_actkind_t -+------> kind
204 * | dtrace_difo_t * --+------> DIFO (if any)
205 * | dtrace_action_t * +------+
206 * +-------------------+ |
208 * +-------------------------------+ (if any)
214 * dtrace_probe() iterates over the ECB list. If the ECB needs less space
215 * than is available in the principal buffer, the ECB is processed: if the
216 * predicate is non-NULL, the DIF object is executed. If the result is
217 * non-zero, the action list is processed, with each action being executed
218 * accordingly. When the action list has been completely executed, processing
219 * advances to the next ECB. The ECB abstraction allows disjoint consumers
220 * to multiplex on single probes.
222 * Execution of the ECB results in consuming dte_size bytes in the buffer
223 * to record data. During execution, dte_needed bytes must be available in
224 * the buffer. This space is used for both recorded data and tuple data.
227 dtrace_epid_t dte_epid; /* enabled probe ID */
228 uint32_t dte_alignment; /* required alignment */
229 size_t dte_needed; /* space needed for execution */
230 size_t dte_size; /* size of recorded payload */
231 dtrace_predicate_t *dte_predicate; /* predicate, if any */
232 dtrace_action_t *dte_action; /* actions, if any */
233 dtrace_ecb_t *dte_next; /* next ECB on probe */
234 dtrace_state_t *dte_state; /* pointer to state */
235 uint32_t dte_cond; /* security condition */
236 dtrace_probe_t *dte_probe; /* pointer to probe */
237 dtrace_action_t *dte_action_last; /* last action on ECB */
238 uint64_t dte_uarg; /* library argument */
241 struct dtrace_predicate {
242 dtrace_difo_t *dtp_difo; /* DIF object */
243 dtrace_cacheid_t dtp_cacheid; /* cache identifier */
244 int dtp_refcnt; /* reference count */
247 struct dtrace_action {
248 dtrace_actkind_t dta_kind; /* kind of action */
249 uint16_t dta_intuple; /* boolean: in aggregation */
250 uint32_t dta_refcnt; /* reference count */
251 dtrace_difo_t *dta_difo; /* pointer to DIFO */
252 dtrace_recdesc_t dta_rec; /* record description */
253 dtrace_action_t *dta_prev; /* previous action */
254 dtrace_action_t *dta_next; /* next action */
257 typedef struct dtrace_aggregation {
258 dtrace_action_t dtag_action; /* action; must be first */
259 dtrace_aggid_t dtag_id; /* identifier */
260 dtrace_ecb_t *dtag_ecb; /* corresponding ECB */
261 dtrace_action_t *dtag_first; /* first action in tuple */
262 uint32_t dtag_base; /* base of aggregation */
263 uint8_t dtag_hasarg; /* boolean: has argument */
264 uint64_t dtag_initial; /* initial value */
265 void (*dtag_aggregate)(uint64_t *, uint64_t, uint64_t);
266 } dtrace_aggregation_t;
271 * Principal buffers, aggregation buffers, and speculative buffers are all
272 * managed with the dtrace_buffer structure. By default, this structure
273 * includes twin data buffers -- dtb_tomax and dtb_xamot -- that serve as the
274 * active and passive buffers, respectively. For speculative buffers,
275 * dtb_xamot will be NULL; for "ring" and "fill" buffers, dtb_xamot will point
276 * to a scratch buffer. For all buffer types, the dtrace_buffer structure is
277 * always allocated on a per-CPU basis; a single dtrace_buffer structure is
278 * never shared among CPUs. (That is, there is never true sharing of the
279 * dtrace_buffer structure; to prevent false sharing of the structure, it must
280 * always be aligned to the coherence granularity -- generally 64 bytes.)
282 * One of the critical design decisions of DTrace is that a given ECB always
283 * stores the same quantity and type of data. This is done to assure that the
284 * only metadata required for an ECB's traced data is the EPID. That is, from
285 * the EPID, the consumer can determine the data layout. (The data buffer
286 * layout is shown schematically below.) By assuring that one can determine
287 * data layout from the EPID, the metadata stream can be separated from the
288 * data stream -- simplifying the data stream enormously. The ECB always
289 * proceeds the recorded data as part of the dtrace_rechdr_t structure that
290 * includes the EPID and a high-resolution timestamp used for output ordering
293 * base of data buffer ---> +--------+--------------------+--------+
294 * | rechdr | data | rechdr |
295 * +--------+------+--------+----+--------+
296 * | data | rechdr | data |
297 * +---------------+--------+-------------+
299 * +--------+--------------------+--------+
300 * | rechdr | data | |
301 * +--------+--------------------+ |
311 * limit of data buffer ---> +--------------------------------------+
313 * When evaluating an ECB, dtrace_probe() determines if the ECB's needs of the
314 * principal buffer (both scratch and payload) exceed the available space. If
315 * the ECB's needs exceed available space (and if the principal buffer policy
316 * is the default "switch" policy), the ECB is dropped, the buffer's drop count
317 * is incremented, and processing advances to the next ECB. If the ECB's needs
318 * can be met with the available space, the ECB is processed, but the offset in
319 * the principal buffer is only advanced if the ECB completes processing
322 * When a buffer is to be switched (either because the buffer is the principal
323 * buffer with a "switch" policy or because it is an aggregation buffer), a
324 * cross call is issued to the CPU associated with the buffer. In the cross
325 * call context, interrupts are disabled, and the active and the inactive
326 * buffers are atomically switched. This involves switching the data pointers,
327 * copying the various state fields (offset, drops, errors, etc.) into their
328 * inactive equivalents, and clearing the state fields. Because interrupts are
329 * disabled during this procedure, the switch is guaranteed to appear atomic to
332 * DTrace Ring Buffering
334 * To process a ring buffer correctly, one must know the oldest valid record.
335 * Processing starts at the oldest record in the buffer and continues until
336 * the end of the buffer is reached. Processing then resumes starting with
337 * the record stored at offset 0 in the buffer, and continues until the
338 * youngest record is processed. If trace records are of a fixed-length,
339 * determining the oldest record is trivial:
341 * - If the ring buffer has not wrapped, the oldest record is the record
342 * stored at offset 0.
344 * - If the ring buffer has wrapped, the oldest record is the record stored
345 * at the current offset.
347 * With variable length records, however, just knowing the current offset
348 * doesn't suffice for determining the oldest valid record: assuming that one
349 * allows for arbitrary data, one has no way of searching forward from the
350 * current offset to find the oldest valid record. (That is, one has no way
351 * of separating data from metadata.) It would be possible to simply refuse to
352 * process any data in the ring buffer between the current offset and the
353 * limit, but this leaves (potentially) an enormous amount of otherwise valid
356 * To effect ring buffering, we track two offsets in the buffer: the current
357 * offset and the _wrapped_ offset. If a request is made to reserve some
358 * amount of data, and the buffer has wrapped, the wrapped offset is
359 * incremented until the wrapped offset minus the current offset is greater
360 * than or equal to the reserve request. This is done by repeatedly looking
361 * up the ECB corresponding to the EPID at the current wrapped offset, and
362 * incrementing the wrapped offset by the size of the data payload
363 * corresponding to that ECB. If this offset is greater than or equal to the
364 * limit of the data buffer, the wrapped offset is set to 0. Thus, the
365 * current offset effectively "chases" the wrapped offset around the buffer.
368 * base of data buffer ---> +------+--------------------+------+
369 * | EPID | data | EPID |
370 * +------+--------+------+----+------+
371 * | data | EPID | data |
372 * +---------------+------+-----------+
374 * +------+---------------------------+
376 * current offset ---> +------+---------------------------+
378 * wrapped offset ---> +------+--------------------+------+
379 * | EPID | data | EPID |
380 * +------+--------+------+----+------+
381 * | data | EPID | data |
382 * +---------------+------+-----------+
385 * . ... valid data ... .
388 * +------+-------------+------+------+
389 * | EPID | data | EPID | data |
390 * +------+------------++------+------+
391 * | data, cont. | leftover |
392 * limit of data buffer ---> +-------------------+--------------+
394 * If the amount of requested buffer space exceeds the amount of space
395 * available between the current offset and the end of the buffer:
397 * (1) all words in the data buffer between the current offset and the limit
398 * of the data buffer (marked "leftover", above) are set to
401 * (2) the wrapped offset is set to zero
403 * (3) the iteration process described above occurs until the wrapped offset
404 * is greater than the amount of desired space.
406 * The wrapped offset is implemented by (re-)using the inactive offset.
407 * In a "switch" buffer policy, the inactive offset stores the offset in
408 * the inactive buffer; in a "ring" buffer policy, it stores the wrapped
411 * DTrace Scratch Buffering
413 * Some ECBs may wish to allocate dynamically-sized temporary scratch memory.
414 * To accommodate such requests easily, scratch memory may be allocated in
415 * the buffer beyond the current offset plus the needed memory of the current
416 * ECB. If there isn't sufficient room in the buffer for the requested amount
417 * of scratch space, the allocation fails and an error is generated. Scratch
418 * memory is tracked in the dtrace_mstate_t and is automatically freed when
419 * the ECB ceases processing. Note that ring buffers cannot allocate their
420 * scratch from the principal buffer -- lest they needlessly overwrite older,
421 * valid data. Ring buffers therefore have their own dedicated scratch buffer
422 * from which scratch is allocated.
424 #define DTRACEBUF_RING 0x0001 /* bufpolicy set to "ring" */
425 #define DTRACEBUF_FILL 0x0002 /* bufpolicy set to "fill" */
426 #define DTRACEBUF_NOSWITCH 0x0004 /* do not switch buffer */
427 #define DTRACEBUF_WRAPPED 0x0008 /* ring buffer has wrapped */
428 #define DTRACEBUF_DROPPED 0x0010 /* drops occurred */
429 #define DTRACEBUF_ERROR 0x0020 /* errors occurred */
430 #define DTRACEBUF_FULL 0x0040 /* "fill" buffer is full */
431 #define DTRACEBUF_CONSUMED 0x0080 /* buffer has been consumed */
432 #define DTRACEBUF_INACTIVE 0x0100 /* buffer is not yet active */
434 typedef struct dtrace_buffer {
435 uint64_t dtb_offset; /* current offset in buffer */
436 uint64_t dtb_size; /* size of buffer */
437 uint32_t dtb_flags; /* flags */
438 uint32_t dtb_drops; /* number of drops */
439 caddr_t dtb_tomax; /* active buffer */
440 caddr_t dtb_xamot; /* inactive buffer */
441 uint32_t dtb_xamot_flags; /* inactive flags */
442 uint32_t dtb_xamot_drops; /* drops in inactive buffer */
443 uint64_t dtb_xamot_offset; /* offset in inactive buffer */
444 uint32_t dtb_errors; /* number of errors */
445 uint32_t dtb_xamot_errors; /* errors in inactive buffer */
447 uint64_t dtb_pad1; /* pad out to 64 bytes */
449 uint64_t dtb_switched; /* time of last switch */
450 uint64_t dtb_interval; /* observed switch interval */
451 uint64_t dtb_pad2[6]; /* pad to avoid false sharing */
455 * DTrace Aggregation Buffers
457 * Aggregation buffers use much of the same mechanism as described above
458 * ("DTrace Buffers"). However, because an aggregation is fundamentally a
459 * hash, there exists dynamic metadata associated with an aggregation buffer
460 * that is not associated with other kinds of buffers. This aggregation
461 * metadata is _only_ relevant for the in-kernel implementation of
462 * aggregations; it is not actually relevant to user-level consumers. To do
463 * this, we allocate dynamic aggregation data (hash keys and hash buckets)
464 * starting below the _limit_ of the buffer, and we allocate data from the
465 * _base_ of the buffer. When the aggregation buffer is copied out, _only_ the
466 * data is copied out; the metadata is simply discarded. Schematically,
467 * aggregation buffers look like:
469 * base of data buffer ---> +-------+------+-----------+-------+
470 * | aggid | key | value | aggid |
471 * +-------+------+-----------+-------+
473 * +-------+-------+-----+------------+
474 * | value | aggid | key | value |
475 * +-------+------++-----+------+-----+
476 * | aggid | key | value | |
477 * +-------+------+-------------+ |
487 * | || +------------+
489 * +---------------------+ |
491 * | (dtrace_aggkey structures) |
493 * +----------------------------------+
495 * | (dtrace_aggbuffer structure) |
497 * limit of data buffer ---> +----------------------------------+
500 * As implied above, just as we assure that ECBs always store a constant
501 * amount of data, we assure that a given aggregation -- identified by its
502 * aggregation ID -- always stores data of a constant quantity and type.
503 * As with EPIDs, this allows the aggregation ID to serve as the metadata for a
506 * Note that the size of the dtrace_aggkey structure must be sizeof (uintptr_t)
507 * aligned. (If this the structure changes such that this becomes false, an
508 * assertion will fail in dtrace_aggregate().)
510 typedef struct dtrace_aggkey {
511 uint32_t dtak_hashval; /* hash value */
512 uint32_t dtak_action:4; /* action -- 4 bits */
513 uint32_t dtak_size:28; /* size -- 28 bits */
514 caddr_t dtak_data; /* data pointer */
515 struct dtrace_aggkey *dtak_next; /* next in hash chain */
518 typedef struct dtrace_aggbuffer {
519 uintptr_t dtagb_hashsize; /* number of buckets */
520 uintptr_t dtagb_free; /* free list of keys */
521 dtrace_aggkey_t **dtagb_hash; /* hash table */
522 } dtrace_aggbuffer_t;
525 * DTrace Speculations
527 * Speculations have a per-CPU buffer and a global state. Once a speculation
528 * buffer has been comitted or discarded, it cannot be reused until all CPUs
529 * have taken the same action (commit or discard) on their respective
530 * speculative buffer. However, because DTrace probes may execute in arbitrary
531 * context, other CPUs cannot simply be cross-called at probe firing time to
532 * perform the necessary commit or discard. The speculation states thus
533 * optimize for the case that a speculative buffer is only active on one CPU at
534 * the time of a commit() or discard() -- for if this is the case, other CPUs
535 * need not take action, and the speculation is immediately available for
536 * reuse. If the speculation is active on multiple CPUs, it must be
537 * asynchronously cleaned -- potentially leading to a higher rate of dirty
538 * speculative drops. The speculation states are as follows:
540 * DTRACESPEC_INACTIVE <= Initial state; inactive speculation
541 * DTRACESPEC_ACTIVE <= Allocated, but not yet speculatively traced to
542 * DTRACESPEC_ACTIVEONE <= Speculatively traced to on one CPU
543 * DTRACESPEC_ACTIVEMANY <= Speculatively traced to on more than one CPU
544 * DTRACESPEC_COMMITTING <= Currently being commited on one CPU
545 * DTRACESPEC_COMMITTINGMANY <= Currently being commited on many CPUs
546 * DTRACESPEC_DISCARDING <= Currently being discarded on many CPUs
548 * The state transition diagram is as follows:
550 * +----------------------------------------------------------+
553 * | +-------------------| COMMITTING |<-----------------+ |
554 * | | +------------+ | |
555 * | | copied spec. ^ commit() on | | discard() on
556 * | | into principal | active CPU | | active CPU
559 * +----------+ +--------+ +-----------+
560 * | INACTIVE |---------------->| ACTIVE |--------------->| ACTIVEONE |
561 * +----------+ speculation() +--------+ speculate() +-----------+
563 * | | | discard() | |
564 * | | asynchronously | discard() on | | speculate()
565 * | | cleaned V inactive CPU | | on inactive
566 * | | +------------+ | | CPU
567 * | +-------------------| DISCARDING |<-----------------+ |
569 * | asynchronously ^ |
570 * | copied spec. | discard() |
571 * | into principal +------------------------+ |
573 * +----------------+ commit() +------------+
574 * | COMMITTINGMANY |<----------------------------------| ACTIVEMANY |
575 * +----------------+ +------------+
577 typedef enum dtrace_speculation_state {
578 DTRACESPEC_INACTIVE = 0,
580 DTRACESPEC_ACTIVEONE,
581 DTRACESPEC_ACTIVEMANY,
582 DTRACESPEC_COMMITTING,
583 DTRACESPEC_COMMITTINGMANY,
584 DTRACESPEC_DISCARDING
585 } dtrace_speculation_state_t;
587 typedef struct dtrace_speculation {
588 dtrace_speculation_state_t dtsp_state; /* current speculation state */
589 int dtsp_cleaning; /* non-zero if being cleaned */
590 dtrace_buffer_t *dtsp_buffer; /* speculative buffer */
591 } dtrace_speculation_t;
594 * DTrace Dynamic Variables
596 * The dynamic variable problem is obviously decomposed into two subproblems:
597 * allocating new dynamic storage, and freeing old dynamic storage. The
598 * presence of the second problem makes the first much more complicated -- or
599 * rather, the absence of the second renders the first trivial. This is the
600 * case with aggregations, for which there is effectively no deallocation of
601 * dynamic storage. (Or more accurately, all dynamic storage is deallocated
602 * when a snapshot is taken of the aggregation.) As DTrace dynamic variables
603 * allow for both dynamic allocation and dynamic deallocation, the
604 * implementation of dynamic variables is quite a bit more complicated than
605 * that of their aggregation kin.
607 * We observe that allocating new dynamic storage is tricky only because the
608 * size can vary -- the allocation problem is much easier if allocation sizes
609 * are uniform. We further observe that in D, the size of dynamic variables is
610 * actually _not_ dynamic -- dynamic variable sizes may be determined by static
611 * analysis of DIF text. (This is true even of putatively dynamically-sized
612 * objects like strings and stacks, the sizes of which are dictated by the
613 * "stringsize" and "stackframes" variables, respectively.) We exploit this by
614 * performing this analysis on all DIF before enabling any probes. For each
615 * dynamic load or store, we calculate the dynamically-allocated size plus the
616 * size of the dtrace_dynvar structure plus the storage required to key the
617 * data. For all DIF, we take the largest value and dub it the _chunksize_.
618 * We then divide dynamic memory into two parts: a hash table that is wide
619 * enough to have every chunk in its own bucket, and a larger region of equal
620 * chunksize units. Whenever we wish to dynamically allocate a variable, we
621 * always allocate a single chunk of memory. Depending on the uniformity of
622 * allocation, this will waste some amount of memory -- but it eliminates the
623 * non-determinism inherent in traditional heap fragmentation.
625 * Dynamic objects are allocated by storing a non-zero value to them; they are
626 * deallocated by storing a zero value to them. Dynamic variables are
627 * complicated enormously by being shared between CPUs. In particular,
628 * consider the following scenario:
631 * +---------------------------------+ +---------------------------------+
633 * | allocates dynamic object a[123] | | |
634 * | by storing the value 345 to it | | |
636 * | | | wishing to load from object |
637 * | | | a[123], performs lookup in |
638 * | | | dynamic variable space |
640 * | deallocates object a[123] by | | |
641 * | storing 0 to it | | |
643 * | allocates dynamic object b[567] | | performs load from a[123] |
644 * | by storing the value 789 to it | | |
648 * This is obviously a race in the D program, but there are nonetheless only
649 * two valid values for CPU B's load from a[123]: 345 or 0. Most importantly,
650 * CPU B may _not_ see the value 789 for a[123].
652 * There are essentially two ways to deal with this:
654 * (1) Explicitly spin-lock variables. That is, if CPU B wishes to load
655 * from a[123], it needs to lock a[123] and hold the lock for the
656 * duration that it wishes to manipulate it.
658 * (2) Avoid reusing freed chunks until it is known that no CPU is referring
661 * The implementation of (1) is rife with complexity, because it requires the
662 * user of a dynamic variable to explicitly decree when they are done using it.
663 * Were all variables by value, this perhaps wouldn't be debilitating -- but
664 * dynamic variables of non-scalar types are tracked by reference. That is, if
665 * a dynamic variable is, say, a string, and that variable is to be traced to,
666 * say, the principal buffer, the DIF emulation code returns to the main
667 * dtrace_probe() loop a pointer to the underlying storage, not the contents of
668 * the storage. Further, code calling on DIF emulation would have to be aware
669 * that the DIF emulation has returned a reference to a dynamic variable that
670 * has been potentially locked. The variable would have to be unlocked after
671 * the main dtrace_probe() loop is finished with the variable, and the main
672 * dtrace_probe() loop would have to be careful to not call any further DIF
673 * emulation while the variable is locked to avoid deadlock. More generally,
674 * if one were to implement (1), DIF emulation code dealing with dynamic
675 * variables could only deal with one dynamic variable at a time (lest deadlock
676 * result). To sum, (1) exports too much subtlety to the users of dynamic
677 * variables -- increasing maintenance burden and imposing serious constraints
678 * on future DTrace development.
680 * The implementation of (2) is also complex, but the complexity is more
681 * manageable. We need to be sure that when a variable is deallocated, it is
682 * not placed on a traditional free list, but rather on a _dirty_ list. Once a
683 * variable is on a dirty list, it cannot be found by CPUs performing a
684 * subsequent lookup of the variable -- but it may still be in use by other
685 * CPUs. To assure that all CPUs that may be seeing the old variable have
686 * cleared out of probe context, a dtrace_sync() can be issued. Once the
687 * dtrace_sync() has completed, it can be known that all CPUs are done
688 * manipulating the dynamic variable -- the dirty list can be atomically
689 * appended to the free list. Unfortunately, there's a slight hiccup in this
690 * mechanism: dtrace_sync() may not be issued from probe context. The
691 * dtrace_sync() must be therefore issued asynchronously from non-probe
692 * context. For this we rely on the DTrace cleaner, a cyclic that runs at the
693 * "cleanrate" frequency. To ease this implementation, we define several chunk
696 * - Dirty. Deallocated chunks, not yet cleaned. Not available.
698 * - Rinsing. Formerly dirty chunks that are currently being asynchronously
699 * cleaned. Not available, but will be shortly. Dynamic variable
700 * allocation may not spin or block for availability, however.
702 * - Clean. Clean chunks, ready for allocation -- but not on the free list.
704 * - Free. Available for allocation.
706 * Moreover, to avoid absurd contention, _each_ of these lists is implemented
707 * on a per-CPU basis. This is only for performance, not correctness; chunks
708 * may be allocated from another CPU's free list. The algorithm for allocation
711 * (1) Attempt to atomically allocate from current CPU's free list. If list
712 * is non-empty and allocation is successful, allocation is complete.
714 * (2) If the clean list is non-empty, atomically move it to the free list,
717 * (3) If the dynamic variable space is in the CLEAN state, look for free
718 * and clean lists on other CPUs by setting the current CPU to the next
719 * CPU, and reattempting (1). If the next CPU is the current CPU (that
720 * is, if all CPUs have been checked), atomically switch the state of
721 * the dynamic variable space based on the following:
723 * - If no free chunks were found and no dirty chunks were found,
724 * atomically set the state to EMPTY.
726 * - If dirty chunks were found, atomically set the state to DIRTY.
728 * - If rinsing chunks were found, atomically set the state to RINSING.
730 * (4) Based on state of dynamic variable space state, increment appropriate
731 * counter to indicate dynamic drops (if in EMPTY state) vs. dynamic
732 * dirty drops (if in DIRTY state) vs. dynamic rinsing drops (if in
733 * RINSING state). Fail the allocation.
735 * The cleaning cyclic operates with the following algorithm: for all CPUs
736 * with a non-empty dirty list, atomically move the dirty list to the rinsing
737 * list. Perform a dtrace_sync(). For all CPUs with a non-empty rinsing list,
738 * atomically move the rinsing list to the clean list. Perform another
739 * dtrace_sync(). By this point, all CPUs have seen the new clean list; the
740 * state of the dynamic variable space can be restored to CLEAN.
742 * There exist two final races that merit explanation. The first is a simple
746 * +---------------------------------+ +---------------------------------+
748 * | allocates dynamic object a[123] | | allocates dynamic object a[123] |
749 * | by storing the value 345 to it | | by storing the value 567 to it |
754 * Again, this is a race in the D program. It can be resolved by having a[123]
755 * hold the value 345 or a[123] hold the value 567 -- but it must be true that
756 * a[123] have only _one_ of these values. (That is, the racing CPUs may not
757 * put the same element twice on the same hash chain.) This is resolved
758 * simply: before the allocation is undertaken, the start of the new chunk's
759 * hash chain is noted. Later, after the allocation is complete, the hash
760 * chain is atomically switched to point to the new element. If this fails
761 * (because of either concurrent allocations or an allocation concurrent with a
762 * deletion), the newly allocated chunk is deallocated to the dirty list, and
763 * the whole process of looking up (and potentially allocating) the dynamic
764 * variable is reattempted.
766 * The final race is a simple deallocation race:
769 * +---------------------------------+ +---------------------------------+
771 * | deallocates dynamic object | | deallocates dynamic object |
772 * | a[123] by storing the value 0 | | a[123] by storing the value 0 |
773 * | to it | | to it |
778 * Once again, this is a race in the D program, but it is one that we must
779 * handle without corrupting the underlying data structures. Because
780 * deallocations require the deletion of a chunk from the middle of a hash
781 * chain, we cannot use a single-word atomic operation to remove it. For this,
782 * we add a spin lock to the hash buckets that is _only_ used for deallocations
783 * (allocation races are handled as above). Further, this spin lock is _only_
784 * held for the duration of the delete; before control is returned to the DIF
785 * emulation code, the hash bucket is unlocked.
787 typedef struct dtrace_key {
788 uint64_t dttk_value; /* data value or data pointer */
789 uint64_t dttk_size; /* 0 if by-val, >0 if by-ref */
792 typedef struct dtrace_tuple {
793 uint32_t dtt_nkeys; /* number of keys in tuple */
794 uint32_t dtt_pad; /* padding */
795 dtrace_key_t dtt_key[1]; /* array of tuple keys */
798 typedef struct dtrace_dynvar {
799 uint64_t dtdv_hashval; /* hash value -- 0 if free */
800 struct dtrace_dynvar *dtdv_next; /* next on list or hash chain */
801 void *dtdv_data; /* pointer to data */
802 dtrace_tuple_t dtdv_tuple; /* tuple key */
805 typedef enum dtrace_dynvar_op {
807 DTRACE_DYNVAR_NOALLOC,
808 DTRACE_DYNVAR_DEALLOC
809 } dtrace_dynvar_op_t;
811 typedef struct dtrace_dynhash {
812 dtrace_dynvar_t *dtdh_chain; /* hash chain for this bucket */
813 uintptr_t dtdh_lock; /* deallocation lock */
815 uintptr_t dtdh_pad[6]; /* pad to avoid false sharing */
817 uintptr_t dtdh_pad[14]; /* pad to avoid false sharing */
821 typedef struct dtrace_dstate_percpu {
822 dtrace_dynvar_t *dtdsc_free; /* free list for this CPU */
823 dtrace_dynvar_t *dtdsc_dirty; /* dirty list for this CPU */
824 dtrace_dynvar_t *dtdsc_rinsing; /* rinsing list for this CPU */
825 dtrace_dynvar_t *dtdsc_clean; /* clean list for this CPU */
826 uint64_t dtdsc_drops; /* number of capacity drops */
827 uint64_t dtdsc_dirty_drops; /* number of dirty drops */
828 uint64_t dtdsc_rinsing_drops; /* number of rinsing drops */
830 uint64_t dtdsc_pad; /* pad to avoid false sharing */
832 uint64_t dtdsc_pad[2]; /* pad to avoid false sharing */
834 } dtrace_dstate_percpu_t;
836 typedef enum dtrace_dstate_state {
837 DTRACE_DSTATE_CLEAN = 0,
840 DTRACE_DSTATE_RINSING
841 } dtrace_dstate_state_t;
843 typedef struct dtrace_dstate {
844 void *dtds_base; /* base of dynamic var. space */
845 size_t dtds_size; /* size of dynamic var. space */
846 size_t dtds_hashsize; /* number of buckets in hash */
847 size_t dtds_chunksize; /* size of each chunk */
848 dtrace_dynhash_t *dtds_hash; /* pointer to hash table */
849 dtrace_dstate_state_t dtds_state; /* current dynamic var. state */
850 dtrace_dstate_percpu_t *dtds_percpu; /* per-CPU dyn. var. state */
854 * DTrace Variable State
856 * The DTrace variable state tracks user-defined variables in its dtrace_vstate
857 * structure. Each DTrace consumer has exactly one dtrace_vstate structure,
858 * but some dtrace_vstate structures may exist without a corresponding DTrace
859 * consumer (see "DTrace Helpers", below). As described in <sys/dtrace.h>,
860 * user-defined variables can have one of three scopes:
862 * DIFV_SCOPE_GLOBAL => global scope
863 * DIFV_SCOPE_THREAD => thread-local scope (i.e. "self->" variables)
864 * DIFV_SCOPE_LOCAL => clause-local scope (i.e. "this->" variables)
866 * The variable state tracks variables by both their scope and their allocation
869 * - The dtvs_globals and dtvs_locals members each point to an array of
870 * dtrace_statvar structures. These structures contain both the variable
871 * metadata (dtrace_difv structures) and the underlying storage for all
872 * statically allocated variables, including statically allocated
873 * DIFV_SCOPE_GLOBAL variables and all DIFV_SCOPE_LOCAL variables.
875 * - The dtvs_tlocals member points to an array of dtrace_difv structures for
876 * DIFV_SCOPE_THREAD variables. As such, this array tracks _only_ the
877 * variable metadata for DIFV_SCOPE_THREAD variables; the underlying storage
878 * is allocated out of the dynamic variable space.
880 * - The dtvs_dynvars member is the dynamic variable state associated with the
881 * variable state. The dynamic variable state (described in "DTrace Dynamic
882 * Variables", above) tracks all DIFV_SCOPE_THREAD variables and all
883 * dynamically-allocated DIFV_SCOPE_GLOBAL variables.
885 typedef struct dtrace_statvar {
886 uint64_t dtsv_data; /* data or pointer to it */
887 size_t dtsv_size; /* size of pointed-to data */
888 int dtsv_refcnt; /* reference count */
889 dtrace_difv_t dtsv_var; /* variable metadata */
892 typedef struct dtrace_vstate {
893 dtrace_state_t *dtvs_state; /* back pointer to state */
894 dtrace_statvar_t **dtvs_globals; /* statically-allocated glbls */
895 int dtvs_nglobals; /* number of globals */
896 dtrace_difv_t *dtvs_tlocals; /* thread-local metadata */
897 int dtvs_ntlocals; /* number of thread-locals */
898 dtrace_statvar_t **dtvs_locals; /* clause-local data */
899 int dtvs_nlocals; /* number of clause-locals */
900 dtrace_dstate_t dtvs_dynvars; /* dynamic variable state */
904 * DTrace Machine State
906 * In the process of processing a fired probe, DTrace needs to track and/or
907 * cache some per-CPU state associated with that particular firing. This is
908 * state that is always discarded after the probe firing has completed, and
909 * much of it is not specific to any DTrace consumer, remaining valid across
910 * all ECBs. This state is tracked in the dtrace_mstate structure.
912 #define DTRACE_MSTATE_ARGS 0x00000001
913 #define DTRACE_MSTATE_PROBE 0x00000002
914 #define DTRACE_MSTATE_EPID 0x00000004
915 #define DTRACE_MSTATE_TIMESTAMP 0x00000008
916 #define DTRACE_MSTATE_STACKDEPTH 0x00000010
917 #define DTRACE_MSTATE_CALLER 0x00000020
918 #define DTRACE_MSTATE_IPL 0x00000040
919 #define DTRACE_MSTATE_FLTOFFS 0x00000080
920 #define DTRACE_MSTATE_WALLTIMESTAMP 0x00000100
921 #define DTRACE_MSTATE_USTACKDEPTH 0x00000200
922 #define DTRACE_MSTATE_UCALLER 0x00000400
924 typedef struct dtrace_mstate {
925 uintptr_t dtms_scratch_base; /* base of scratch space */
926 uintptr_t dtms_scratch_ptr; /* current scratch pointer */
927 size_t dtms_scratch_size; /* scratch size */
928 uint32_t dtms_present; /* variables that are present */
929 uint64_t dtms_arg[5]; /* cached arguments */
930 dtrace_epid_t dtms_epid; /* current EPID */
931 uint64_t dtms_timestamp; /* cached timestamp */
932 hrtime_t dtms_walltimestamp; /* cached wall timestamp */
933 int dtms_stackdepth; /* cached stackdepth */
934 int dtms_ustackdepth; /* cached ustackdepth */
935 struct dtrace_probe *dtms_probe; /* current probe */
936 uintptr_t dtms_caller; /* cached caller */
937 uint64_t dtms_ucaller; /* cached user-level caller */
938 int dtms_ipl; /* cached interrupt pri lev */
939 int dtms_fltoffs; /* faulting DIFO offset */
940 uintptr_t dtms_strtok; /* saved strtok() pointer */
941 uintptr_t dtms_strtok_limit; /* upper bound of strtok ptr */
942 uint32_t dtms_access; /* memory access rights */
943 dtrace_difo_t *dtms_difo; /* current dif object */
944 file_t *dtms_getf; /* cached rval of getf() */
947 #define DTRACE_COND_OWNER 0x1
948 #define DTRACE_COND_USERMODE 0x2
949 #define DTRACE_COND_ZONEOWNER 0x4
951 #define DTRACE_PROBEKEY_MAXDEPTH 8 /* max glob recursion depth */
954 * Access flag used by dtrace_mstate.dtms_access.
956 #define DTRACE_ACCESS_KERNEL 0x1 /* the priv to read kmem */
962 * Each DTrace consumer is in one of several states, which (for purposes of
963 * avoiding yet-another overloading of the noun "state") we call the current
964 * _activity_. The activity transitions on dtrace_go() (from DTRACIOCGO), on
965 * dtrace_stop() (from DTRACIOCSTOP) and on the exit() action. Activities may
966 * only transition in one direction; the activity transition diagram is a
967 * directed acyclic graph. The activity transition diagram is as follows:
970 * +----------+ +--------+ +--------+
971 * | INACTIVE |------------------>| WARMUP |------------------>| ACTIVE |
972 * +----------+ dtrace_go(), +--------+ dtrace_go(), +--------+
973 * before BEGIN | after BEGIN | | |
975 * exit() action | | | |
976 * from BEGIN ECB | | | |
979 * +----------+ exit() action | | |
980 * +-----------------------------| DRAINING |<-------------------+ | |
983 * | dtrace_stop(), | | |
987 * | +---------+ +----------+ | |
988 * | | STOPPED |<----------------| COOLDOWN |<----------------------+ |
989 * | +---------+ dtrace_stop(), +----------+ dtrace_stop(), |
990 * | after END before END |
993 * +----------------------------->| KILLED |<--------------------------+
994 * deadman timeout or +--------+ deadman timeout or
995 * killed consumer killed consumer
997 * Note that once a DTrace consumer has stopped tracing, there is no way to
998 * restart it; if a DTrace consumer wishes to restart tracing, it must reopen
999 * the DTrace pseudodevice.
1001 typedef enum dtrace_activity {
1002 DTRACE_ACTIVITY_INACTIVE = 0, /* not yet running */
1003 DTRACE_ACTIVITY_WARMUP, /* while starting */
1004 DTRACE_ACTIVITY_ACTIVE, /* running */
1005 DTRACE_ACTIVITY_DRAINING, /* before stopping */
1006 DTRACE_ACTIVITY_COOLDOWN, /* while stopping */
1007 DTRACE_ACTIVITY_STOPPED, /* after stopping */
1008 DTRACE_ACTIVITY_KILLED /* killed */
1009 } dtrace_activity_t;
1012 * DTrace Helper Implementation
1014 * A description of the helper architecture may be found in <sys/dtrace.h>.
1015 * Each process contains a pointer to its helpers in its p_dtrace_helpers
1016 * member. This is a pointer to a dtrace_helpers structure, which contains an
1017 * array of pointers to dtrace_helper structures, helper variable state (shared
1018 * among a process's helpers) and a generation count. (The generation count is
1019 * used to provide an identifier when a helper is added so that it may be
1020 * subsequently removed.) The dtrace_helper structure is self-explanatory,
1021 * containing pointers to the objects needed to execute the helper. Note that
1022 * helpers are _duplicated_ across fork(2), and destroyed on exec(2). No more
1023 * than dtrace_helpers_max are allowed per-process.
1025 #define DTRACE_HELPER_ACTION_USTACK 0
1026 #define DTRACE_NHELPER_ACTIONS 1
1028 typedef struct dtrace_helper_action {
1029 int dtha_generation; /* helper action generation */
1030 int dtha_nactions; /* number of actions */
1031 dtrace_difo_t *dtha_predicate; /* helper action predicate */
1032 dtrace_difo_t **dtha_actions; /* array of actions */
1033 struct dtrace_helper_action *dtha_next; /* next helper action */
1034 } dtrace_helper_action_t;
1036 typedef struct dtrace_helper_provider {
1037 int dthp_generation; /* helper provider generation */
1038 uint32_t dthp_ref; /* reference count */
1039 dof_helper_t dthp_prov; /* DOF w/ provider and probes */
1040 } dtrace_helper_provider_t;
1042 typedef struct dtrace_helpers {
1043 dtrace_helper_action_t **dthps_actions; /* array of helper actions */
1044 dtrace_vstate_t dthps_vstate; /* helper action var. state */
1045 dtrace_helper_provider_t **dthps_provs; /* array of providers */
1046 uint_t dthps_nprovs; /* count of providers */
1047 uint_t dthps_maxprovs; /* provider array size */
1048 int dthps_generation; /* current generation */
1049 pid_t dthps_pid; /* pid of associated proc */
1050 int dthps_deferred; /* helper in deferred list */
1051 struct dtrace_helpers *dthps_next; /* next pointer */
1052 struct dtrace_helpers *dthps_prev; /* prev pointer */
1056 * DTrace Helper Action Tracing
1058 * Debugging helper actions can be arduous. To ease the development and
1059 * debugging of helpers, DTrace contains a tracing-framework-within-a-tracing-
1060 * framework: helper tracing. If dtrace_helptrace_enabled is non-zero (which
1061 * it is by default on DEBUG kernels), all helper activity will be traced to a
1062 * global, in-kernel ring buffer. Each entry includes a pointer to the specific
1063 * helper, the location within the helper, and a trace of all local variables.
1064 * The ring buffer may be displayed in a human-readable format with the
1065 * ::dtrace_helptrace mdb(1) dcmd.
1067 #define DTRACE_HELPTRACE_NEXT (-1)
1068 #define DTRACE_HELPTRACE_DONE (-2)
1069 #define DTRACE_HELPTRACE_ERR (-3)
1071 typedef struct dtrace_helptrace {
1072 dtrace_helper_action_t *dtht_helper; /* helper action */
1073 int dtht_where; /* where in helper action */
1074 int dtht_nlocals; /* number of locals */
1075 int dtht_fault; /* type of fault (if any) */
1076 int dtht_fltoffs; /* DIF offset */
1077 uint64_t dtht_illval; /* faulting value */
1078 uint64_t dtht_locals[1]; /* local variables */
1079 } dtrace_helptrace_t;
1082 * DTrace Credentials
1084 * In probe context, we have limited flexibility to examine the credentials
1085 * of the DTrace consumer that created a particular enabling. We use
1086 * the Least Privilege interfaces to cache the consumer's cred pointer and
1087 * some facts about that credential in a dtrace_cred_t structure. These
1088 * can limit the consumer's breadth of visibility and what actions the
1089 * consumer may take.
1091 #define DTRACE_CRV_ALLPROC 0x01
1092 #define DTRACE_CRV_KERNEL 0x02
1093 #define DTRACE_CRV_ALLZONE 0x04
1095 #define DTRACE_CRV_ALL (DTRACE_CRV_ALLPROC | DTRACE_CRV_KERNEL | \
1098 #define DTRACE_CRA_PROC 0x0001
1099 #define DTRACE_CRA_PROC_CONTROL 0x0002
1100 #define DTRACE_CRA_PROC_DESTRUCTIVE_ALLUSER 0x0004
1101 #define DTRACE_CRA_PROC_DESTRUCTIVE_ALLZONE 0x0008
1102 #define DTRACE_CRA_PROC_DESTRUCTIVE_CREDCHG 0x0010
1103 #define DTRACE_CRA_KERNEL 0x0020
1104 #define DTRACE_CRA_KERNEL_DESTRUCTIVE 0x0040
1106 #define DTRACE_CRA_ALL (DTRACE_CRA_PROC | \
1107 DTRACE_CRA_PROC_CONTROL | \
1108 DTRACE_CRA_PROC_DESTRUCTIVE_ALLUSER | \
1109 DTRACE_CRA_PROC_DESTRUCTIVE_ALLZONE | \
1110 DTRACE_CRA_PROC_DESTRUCTIVE_CREDCHG | \
1111 DTRACE_CRA_KERNEL | \
1112 DTRACE_CRA_KERNEL_DESTRUCTIVE)
1114 typedef struct dtrace_cred {
1116 uint8_t dcr_destructive;
1117 uint8_t dcr_visible;
1118 uint16_t dcr_action;
1122 * DTrace Consumer State
1124 * Each DTrace consumer has an associated dtrace_state structure that contains
1125 * its in-kernel DTrace state -- including options, credentials, statistics and
1126 * pointers to ECBs, buffers, speculations and formats. A dtrace_state
1127 * structure is also allocated for anonymous enablings. When anonymous state
1128 * is grabbed, the grabbing consumers dts_anon pointer is set to the grabbed
1129 * dtrace_state structure.
1131 struct dtrace_state {
1133 dev_t dts_dev; /* device */
1135 struct cdev *dts_dev; /* device */
1137 int dts_necbs; /* total number of ECBs */
1138 dtrace_ecb_t **dts_ecbs; /* array of ECBs */
1139 dtrace_epid_t dts_epid; /* next EPID to allocate */
1140 size_t dts_needed; /* greatest needed space */
1141 struct dtrace_state *dts_anon; /* anon. state, if grabbed */
1142 dtrace_activity_t dts_activity; /* current activity */
1143 dtrace_vstate_t dts_vstate; /* variable state */
1144 dtrace_buffer_t *dts_buffer; /* principal buffer */
1145 dtrace_buffer_t *dts_aggbuffer; /* aggregation buffer */
1146 dtrace_speculation_t *dts_speculations; /* speculation array */
1147 int dts_nspeculations; /* number of speculations */
1148 int dts_naggregations; /* number of aggregations */
1149 dtrace_aggregation_t **dts_aggregations; /* aggregation array */
1151 vmem_t *dts_aggid_arena; /* arena for aggregation IDs */
1153 struct unrhdr *dts_aggid_arena; /* arena for aggregation IDs */
1155 uint64_t dts_errors; /* total number of errors */
1156 uint32_t dts_speculations_busy; /* number of spec. busy */
1157 uint32_t dts_speculations_unavail; /* number of spec unavail */
1158 uint32_t dts_stkstroverflows; /* stack string tab overflows */
1159 uint32_t dts_dblerrors; /* errors in ERROR probes */
1160 uint32_t dts_reserve; /* space reserved for END */
1161 hrtime_t dts_laststatus; /* time of last status */
1163 cyclic_id_t dts_cleaner; /* cleaning cyclic */
1164 cyclic_id_t dts_deadman; /* deadman cyclic */
1166 struct callout dts_cleaner; /* Cleaning callout. */
1167 struct callout dts_deadman; /* Deadman callout. */
1169 hrtime_t dts_alive; /* time last alive */
1170 char dts_speculates; /* boolean: has speculations */
1171 char dts_destructive; /* boolean: has dest. actions */
1172 int dts_nformats; /* number of formats */
1173 char **dts_formats; /* format string array */
1174 dtrace_optval_t dts_options[DTRACEOPT_MAX]; /* options */
1175 dtrace_cred_t dts_cred; /* credentials */
1176 size_t dts_nretained; /* number of retained enabs */
1177 int dts_getf; /* number of getf() calls */
1178 uint64_t dts_rstate[NCPU][2]; /* per-CPU random state */
1181 struct dtrace_provider {
1182 dtrace_pattr_t dtpv_attr; /* provider attributes */
1183 dtrace_ppriv_t dtpv_priv; /* provider privileges */
1184 dtrace_pops_t dtpv_pops; /* provider operations */
1185 char *dtpv_name; /* provider name */
1186 void *dtpv_arg; /* provider argument */
1187 hrtime_t dtpv_defunct; /* when made defunct */
1188 struct dtrace_provider *dtpv_next; /* next provider */
1191 struct dtrace_meta {
1192 dtrace_mops_t dtm_mops; /* meta provider operations */
1193 char *dtm_name; /* meta provider name */
1194 void *dtm_arg; /* meta provider user arg */
1195 uint64_t dtm_count; /* no. of associated provs. */
1201 * A dtrace_enabling structure is used to track a collection of ECB
1202 * descriptions -- before they have been turned into actual ECBs. This is
1203 * created as a result of DOF processing, and is generally used to generate
1204 * ECBs immediately thereafter. However, enablings are also generally
1205 * retained should the probes they describe be created at a later time; as
1206 * each new module or provider registers with the framework, the retained
1207 * enablings are reevaluated, with any new match resulting in new ECBs. To
1208 * prevent probes from being matched more than once, the enabling tracks the
1209 * last probe generation matched, and only matches probes from subsequent
1212 typedef struct dtrace_enabling {
1213 dtrace_ecbdesc_t **dten_desc; /* all ECB descriptions */
1214 int dten_ndesc; /* number of ECB descriptions */
1215 int dten_maxdesc; /* size of ECB array */
1216 dtrace_vstate_t *dten_vstate; /* associated variable state */
1217 dtrace_genid_t dten_probegen; /* matched probe generation */
1218 dtrace_ecbdesc_t *dten_current; /* current ECB description */
1219 int dten_error; /* current error value */
1220 int dten_primed; /* boolean: set if primed */
1221 struct dtrace_enabling *dten_prev; /* previous enabling */
1222 struct dtrace_enabling *dten_next; /* next enabling */
1223 } dtrace_enabling_t;
1226 * DTrace Anonymous Enablings
1228 * Anonymous enablings are DTrace enablings that are not associated with a
1229 * controlling process, but rather derive their enabling from DOF stored as
1230 * properties in the dtrace.conf file. If there is an anonymous enabling, a
1231 * DTrace consumer state and enabling are created on attach. The state may be
1232 * subsequently grabbed by the first consumer specifying the "grabanon"
1233 * option. As long as an anonymous DTrace enabling exists, dtrace(7D) will
1236 typedef struct dtrace_anon {
1237 dtrace_state_t *dta_state; /* DTrace consumer state */
1238 dtrace_enabling_t *dta_enabling; /* pointer to enabling */
1239 processorid_t dta_beganon; /* which CPU BEGIN ran on */
1243 * DTrace Error Debugging
1246 #define DTRACE_ERRDEBUG
1249 #ifdef DTRACE_ERRDEBUG
1251 typedef struct dtrace_errhash {
1252 const char *dter_msg; /* error message */
1253 int dter_count; /* number of times seen */
1256 #define DTRACE_ERRHASHSZ 256 /* must be > number of err msgs */
1258 #endif /* DTRACE_ERRDEBUG */
1261 * DTrace Toxic Ranges
1263 * DTrace supports safe loads from probe context; if the address turns out to
1264 * be invalid, a bit will be set by the kernel indicating that DTrace
1265 * encountered a memory error, and DTrace will propagate the error to the user
1266 * accordingly. However, there may exist some regions of memory in which an
1267 * arbitrary load can change system state, and from which it is impossible to
1268 * recover from such a load after it has been attempted. Examples of this may
1269 * include memory in which programmable I/O registers are mapped (for which a
1270 * read may have some implications for the device) or (in the specific case of
1271 * UltraSPARC-I and -II) the virtual address hole. The platform is required
1272 * to make DTrace aware of these toxic ranges; DTrace will then check that
1273 * target addresses are not in a toxic range before attempting to issue a
1276 typedef struct dtrace_toxrange {
1277 uintptr_t dtt_base; /* base of toxic range */
1278 uintptr_t dtt_limit; /* limit of toxic range */
1279 } dtrace_toxrange_t;
1282 extern uint64_t dtrace_getarg(int, int);
1284 extern uint64_t __noinline dtrace_getarg(int, int);
1286 extern greg_t dtrace_getfp(void);
1287 extern int dtrace_getipl(void);
1288 extern uintptr_t dtrace_caller(int);
1289 extern uint32_t dtrace_cas32(uint32_t *, uint32_t, uint32_t);
1290 extern void *dtrace_casptr(volatile void *, volatile void *, volatile void *);
1291 extern void dtrace_copyin(uintptr_t, uintptr_t, size_t, volatile uint16_t *);
1292 extern void dtrace_copyinstr(uintptr_t, uintptr_t, size_t, volatile uint16_t *);
1293 extern void dtrace_copyout(uintptr_t, uintptr_t, size_t, volatile uint16_t *);
1294 extern void dtrace_copyoutstr(uintptr_t, uintptr_t, size_t,
1295 volatile uint16_t *);
1296 extern void dtrace_getpcstack(pc_t *, int, int, uint32_t *);
1297 extern ulong_t dtrace_getreg(struct trapframe *, uint_t);
1298 extern int dtrace_getstackdepth(int);
1299 extern void dtrace_getupcstack(uint64_t *, int);
1300 extern void dtrace_getufpstack(uint64_t *, uint64_t *, int);
1301 extern int dtrace_getustackdepth(void);
1302 extern uintptr_t dtrace_fulword(void *);
1303 extern uint8_t dtrace_fuword8(void *);
1304 extern uint16_t dtrace_fuword16(void *);
1305 extern uint32_t dtrace_fuword32(void *);
1306 extern uint64_t dtrace_fuword64(void *);
1307 extern void dtrace_probe_error(dtrace_state_t *, dtrace_epid_t, int, int,
1309 extern int dtrace_assfail(const char *, const char *, int);
1310 extern int dtrace_attached(void);
1312 extern hrtime_t dtrace_gethrestime(void);
1316 extern void dtrace_flush_windows(void);
1317 extern void dtrace_flush_user_windows(void);
1318 extern uint_t dtrace_getotherwin(void);
1319 extern uint_t dtrace_getfprs(void);
1321 extern void dtrace_copy(uintptr_t, uintptr_t, size_t);
1322 extern void dtrace_copystr(uintptr_t, uintptr_t, size_t, volatile uint16_t *);
1328 * DTrace calls ASSERT and VERIFY from probe context. To assure that a failed
1329 * ASSERT or VERIFY does not induce a markedly more catastrophic failure (e.g.,
1330 * one from which a dump cannot be gleaned), DTrace must define its own ASSERT
1331 * and VERIFY macros to be ones that may safely be called from probe context.
1332 * This header file must thus be included by any DTrace component that calls
1333 * ASSERT and/or VERIFY from probe context, and _only_ by those components.
1334 * (The only exception to this is kernel debugging infrastructure at user-level
1335 * that doesn't depend on calling ASSERT.)
1339 #define VERIFY(EX) ((void)((EX) || \
1340 dtrace_assfail(#EX, __FILE__, __LINE__)))
1342 #define ASSERT(EX) ((void)((EX) || \
1343 dtrace_assfail(#EX, __FILE__, __LINE__)))
1345 #define ASSERT(X) ((void)0)
1352 #endif /* _SYS_DTRACE_IMPL_H */
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