1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #ifndef _SYS_DTRACE_IMPL_H 27 #define _SYS_DTRACE_IMPL_H 28 29 #pragma ident "%Z%%M% %I% %E% SMI" 30 31 #ifdef __cplusplus 32 extern "C" { 33 #endif 34 35 /* 36 * DTrace Dynamic Tracing Software: Kernel Implementation Interfaces 37 * 38 * Note: The contents of this file are private to the implementation of the 39 * Solaris system and DTrace subsystem and are subject to change at any time 40 * without notice. Applications and drivers using these interfaces will fail 41 * to run on future releases. These interfaces should not be used for any 42 * purpose except those expressly outlined in dtrace(7D) and libdtrace(3LIB). 43 * Please refer to the "Solaris Dynamic Tracing Guide" for more information. 44 */ 45 46 #include <sys/dtrace.h> 47 48 /* 49 * DTrace Implementation Constants and Typedefs 50 */ 51 #define DTRACE_MAXPROPLEN 128 52 #define DTRACE_DYNVAR_CHUNKSIZE 256 53 54 struct dtrace_probe; 55 struct dtrace_ecb; 56 struct dtrace_predicate; 57 struct dtrace_action; 58 struct dtrace_provider; 59 struct dtrace_state; 60 61 typedef struct dtrace_probe dtrace_probe_t; 62 typedef struct dtrace_ecb dtrace_ecb_t; 63 typedef struct dtrace_predicate dtrace_predicate_t; 64 typedef struct dtrace_action dtrace_action_t; 65 typedef struct dtrace_provider dtrace_provider_t; 66 typedef struct dtrace_meta dtrace_meta_t; 67 typedef struct dtrace_state dtrace_state_t; 68 typedef uint32_t dtrace_optid_t; 69 typedef uint32_t dtrace_specid_t; 70 typedef uint64_t dtrace_genid_t; 71 72 /* 73 * DTrace Probes 74 * 75 * The probe is the fundamental unit of the DTrace architecture. Probes are 76 * created by DTrace providers, and managed by the DTrace framework. A probe 77 * is identified by a unique <provider, module, function, name> tuple, and has 78 * a unique probe identifier assigned to it. (Some probes are not associated 79 * with a specific point in text; these are called _unanchored probes_ and have 80 * no module or function associated with them.) Probes are represented as a 81 * dtrace_probe structure. To allow quick lookups based on each element of the 82 * probe tuple, probes are hashed by each of provider, module, function and 83 * name. (If a lookup is performed based on a regular expression, a 84 * dtrace_probekey is prepared, and a linear search is performed.) Each probe 85 * is additionally pointed to by a linear array indexed by its identifier. The 86 * identifier is the provider's mechanism for indicating to the DTrace 87 * framework that a probe has fired: the identifier is passed as the first 88 * argument to dtrace_probe(), where it is then mapped into the corresponding 89 * dtrace_probe structure. From the dtrace_probe structure, dtrace_probe() can 90 * iterate over the probe's list of enabling control blocks; see "DTrace 91 * Enabling Control Blocks", below.) 92 */ 93 struct dtrace_probe { 94 dtrace_id_t dtpr_id; /* probe identifier */ 95 dtrace_ecb_t *dtpr_ecb; /* ECB list; see below */ 96 dtrace_ecb_t *dtpr_ecb_last; /* last ECB in list */ 97 void *dtpr_arg; /* provider argument */ 98 dtrace_cacheid_t dtpr_predcache; /* predicate cache ID */ 99 int dtpr_aframes; /* artificial frames */ 100 dtrace_provider_t *dtpr_provider; /* pointer to provider */ 101 char *dtpr_mod; /* probe's module name */ 102 char *dtpr_func; /* probe's function name */ 103 char *dtpr_name; /* probe's name */ 104 dtrace_probe_t *dtpr_nextmod; /* next in module hash */ 105 dtrace_probe_t *dtpr_prevmod; /* previous in module hash */ 106 dtrace_probe_t *dtpr_nextfunc; /* next in function hash */ 107 dtrace_probe_t *dtpr_prevfunc; /* previous in function hash */ 108 dtrace_probe_t *dtpr_nextname; /* next in name hash */ 109 dtrace_probe_t *dtpr_prevname; /* previous in name hash */ 110 dtrace_genid_t dtpr_gen; /* probe generation ID */ 111 }; 112 113 typedef int dtrace_probekey_f(const char *, const char *, int); 114 115 typedef struct dtrace_probekey { 116 const char *dtpk_prov; /* provider name to match */ 117 dtrace_probekey_f *dtpk_pmatch; /* provider matching function */ 118 const char *dtpk_mod; /* module name to match */ 119 dtrace_probekey_f *dtpk_mmatch; /* module matching function */ 120 const char *dtpk_func; /* func name to match */ 121 dtrace_probekey_f *dtpk_fmatch; /* func matching function */ 122 const char *dtpk_name; /* name to match */ 123 dtrace_probekey_f *dtpk_nmatch; /* name matching function */ 124 dtrace_id_t dtpk_id; /* identifier to match */ 125 } dtrace_probekey_t; 126 127 typedef struct dtrace_hashbucket { 128 struct dtrace_hashbucket *dthb_next; /* next on hash chain */ 129 dtrace_probe_t *dthb_chain; /* chain of probes */ 130 int dthb_len; /* number of probes here */ 131 } dtrace_hashbucket_t; 132 133 typedef struct dtrace_hash { 134 dtrace_hashbucket_t **dth_tab; /* hash table */ 135 int dth_size; /* size of hash table */ 136 int dth_mask; /* mask to index into table */ 137 int dth_nbuckets; /* total number of buckets */ 138 uintptr_t dth_nextoffs; /* offset of next in probe */ 139 uintptr_t dth_prevoffs; /* offset of prev in probe */ 140 uintptr_t dth_stroffs; /* offset of str in probe */ 141 } dtrace_hash_t; 142 143 /* 144 * DTrace Enabling Control Blocks 145 * 146 * When a provider wishes to fire a probe, it calls into dtrace_probe(), 147 * passing the probe identifier as the first argument. As described above, 148 * dtrace_probe() maps the identifier into a pointer to a dtrace_probe_t 149 * structure. This structure contains information about the probe, and a 150 * pointer to the list of Enabling Control Blocks (ECBs). Each ECB points to 151 * DTrace consumer state, and contains an optional predicate, and a list of 152 * actions. (Shown schematically below.) The ECB abstraction allows a single 153 * probe to be multiplexed across disjoint consumers, or across disjoint 154 * enablings of a single probe within one consumer. 155 * 156 * Enabling Control Block 157 * dtrace_ecb_t 158 * +------------------------+ 159 * | dtrace_epid_t ---------+--------------> Enabled Probe ID (EPID) 160 * | dtrace_state_t * ------+--------------> State associated with this ECB 161 * | dtrace_predicate_t * --+---------+ 162 * | dtrace_action_t * -----+----+ | 163 * | dtrace_ecb_t * ---+ | | | Predicate (if any) 164 * +-------------------+----+ | | dtrace_predicate_t 165 * | | +---> +--------------------+ 166 * | | | dtrace_difo_t * ---+----> DIFO 167 * | | +--------------------+ 168 * | | 169 * Next ECB | | Action 170 * (if any) | | dtrace_action_t 171 * : +--> +-------------------+ 172 * : | dtrace_actkind_t -+------> kind 173 * v | dtrace_difo_t * --+------> DIFO (if any) 174 * | dtrace_recdesc_t -+------> record descr. 175 * | dtrace_action_t * +------+ 176 * +-------------------+ | 177 * | Next action 178 * +-------------------------------+ (if any) 179 * | 180 * | Action 181 * | dtrace_action_t 182 * +--> +-------------------+ 183 * | dtrace_actkind_t -+------> kind 184 * | dtrace_difo_t * --+------> DIFO (if any) 185 * | dtrace_action_t * +------+ 186 * +-------------------+ | 187 * | Next action 188 * +-------------------------------+ (if any) 189 * | 190 * : 191 * v 192 * 193 * 194 * dtrace_probe() iterates over the ECB list. If the ECB needs less space 195 * than is available in the principal buffer, the ECB is processed: if the 196 * predicate is non-NULL, the DIF object is executed. If the result is 197 * non-zero, the action list is processed, with each action being executed 198 * accordingly. When the action list has been completely executed, processing 199 * advances to the next ECB. processing advances to the next ECB. If the 200 * result is non-zero; For each ECB, it first determines the The ECB 201 * abstraction allows disjoint consumers to multiplex on single probes. 202 */ 203 struct dtrace_ecb { 204 dtrace_epid_t dte_epid; /* enabled probe ID */ 205 uint32_t dte_alignment; /* required alignment */ 206 size_t dte_needed; /* bytes needed */ 207 size_t dte_size; /* total size of payload */ 208 dtrace_predicate_t *dte_predicate; /* predicate, if any */ 209 dtrace_action_t *dte_action; /* actions, if any */ 210 dtrace_ecb_t *dte_next; /* next ECB on probe */ 211 dtrace_state_t *dte_state; /* pointer to state */ 212 uint32_t dte_cond; /* security condition */ 213 dtrace_probe_t *dte_probe; /* pointer to probe */ 214 dtrace_action_t *dte_action_last; /* last action on ECB */ 215 uint64_t dte_uarg; /* library argument */ 216 }; 217 218 struct dtrace_predicate { 219 dtrace_difo_t *dtp_difo; /* DIF object */ 220 dtrace_cacheid_t dtp_cacheid; /* cache identifier */ 221 int dtp_refcnt; /* reference count */ 222 }; 223 224 struct dtrace_action { 225 dtrace_actkind_t dta_kind; /* kind of action */ 226 uint16_t dta_intuple; /* boolean: in aggregation */ 227 uint32_t dta_refcnt; /* reference count */ 228 dtrace_difo_t *dta_difo; /* pointer to DIFO */ 229 dtrace_recdesc_t dta_rec; /* record description */ 230 dtrace_action_t *dta_prev; /* previous action */ 231 dtrace_action_t *dta_next; /* next action */ 232 }; 233 234 typedef struct dtrace_aggregation { 235 dtrace_action_t dtag_action; /* action; must be first */ 236 dtrace_aggid_t dtag_id; /* identifier */ 237 dtrace_ecb_t *dtag_ecb; /* corresponding ECB */ 238 dtrace_action_t *dtag_first; /* first action in tuple */ 239 uint32_t dtag_base; /* base of aggregation */ 240 uint8_t dtag_hasarg; /* boolean: has argument */ 241 uint64_t dtag_initial; /* initial value */ 242 void (*dtag_aggregate)(uint64_t *, uint64_t, uint64_t); 243 } dtrace_aggregation_t; 244 245 /* 246 * DTrace Buffers 247 * 248 * Principal buffers, aggregation buffers, and speculative buffers are all 249 * managed with the dtrace_buffer structure. By default, this structure 250 * includes twin data buffers -- dtb_tomax and dtb_xamot -- that serve as the 251 * active and passive buffers, respectively. For speculative buffers, 252 * dtb_xamot will be NULL; for "ring" and "fill" buffers, dtb_xamot will point 253 * to a scratch buffer. For all buffer types, the dtrace_buffer structure is 254 * always allocated on a per-CPU basis; a single dtrace_buffer structure is 255 * never shared among CPUs. (That is, there is never true sharing of the 256 * dtrace_buffer structure; to prevent false sharing of the structure, it must 257 * always be aligned to the coherence granularity -- generally 64 bytes.) 258 * 259 * One of the critical design decisions of DTrace is that a given ECB always 260 * stores the same quantity and type of data. This is done to assure that the 261 * only metadata required for an ECB's traced data is the EPID. That is, from 262 * the EPID, the consumer can determine the data layout. (The data buffer 263 * layout is shown schematically below.) By assuring that one can determine 264 * data layout from the EPID, the metadata stream can be separated from the 265 * data stream -- simplifying the data stream enormously. 266 * 267 * base of data buffer ---> +------+--------------------+------+ 268 * | EPID | data | EPID | 269 * +------+--------+------+----+------+ 270 * | data | EPID | data | 271 * +---------------+------+-----------+ 272 * | data, cont. | 273 * +------+--------------------+------+ 274 * | EPID | data | | 275 * +------+--------------------+ | 276 * | || | 277 * | || | 278 * | \/ | 279 * : : 280 * . . 281 * . . 282 * . . 283 * : : 284 * | | 285 * limit of data buffer ---> +----------------------------------+ 286 * 287 * When evaluating an ECB, dtrace_probe() determines if the ECB's needs of the 288 * principal buffer (both scratch and payload) exceed the available space. If 289 * the ECB's needs exceed available space (and if the principal buffer policy 290 * is the default "switch" policy), the ECB is dropped, the buffer's drop count 291 * is incremented, and processing advances to the next ECB. If the ECB's needs 292 * can be met with the available space, the ECB is processed, but the offset in 293 * the principal buffer is only advanced if the ECB completes processing 294 * without error. 295 * 296 * When a buffer is to be switched (either because the buffer is the principal 297 * buffer with a "switch" policy or because it is an aggregation buffer), a 298 * cross call is issued to the CPU associated with the buffer. In the cross 299 * call context, interrupts are disabled, and the active and the inactive 300 * buffers are atomically switched. This involves switching the data pointers, 301 * copying the various state fields (offset, drops, errors, etc.) into their 302 * inactive equivalents, and clearing the state fields. Because interrupts are 303 * disabled during this procedure, the switch is guaranteed to appear atomic to 304 * dtrace_probe(). 305 * 306 * DTrace Ring Buffering 307 * 308 * To process a ring buffer correctly, one must know the oldest valid record. 309 * Processing starts at the oldest record in the buffer and continues until 310 * the end of the buffer is reached. Processing then resumes starting with 311 * the record stored at offset 0 in the buffer, and continues until the 312 * youngest record is processed. If trace records are of a fixed-length, 313 * determining the oldest record is trivial: 314 * 315 * - If the ring buffer has not wrapped, the oldest record is the record 316 * stored at offset 0. 317 * 318 * - If the ring buffer has wrapped, the oldest record is the record stored 319 * at the current offset. 320 * 321 * With variable length records, however, just knowing the current offset 322 * doesn't suffice for determining the oldest valid record: assuming that one 323 * allows for arbitrary data, one has no way of searching forward from the 324 * current offset to find the oldest valid record. (That is, one has no way 325 * of separating data from metadata.) It would be possible to simply refuse to 326 * process any data in the ring buffer between the current offset and the 327 * limit, but this leaves (potentially) an enormous amount of otherwise valid 328 * data unprocessed. 329 * 330 * To effect ring buffering, we track two offsets in the buffer: the current 331 * offset and the _wrapped_ offset. If a request is made to reserve some 332 * amount of data, and the buffer has wrapped, the wrapped offset is 333 * incremented until the wrapped offset minus the current offset is greater 334 * than or equal to the reserve request. This is done by repeatedly looking 335 * up the ECB corresponding to the EPID at the current wrapped offset, and 336 * incrementing the wrapped offset by the size of the data payload 337 * corresponding to that ECB. If this offset is greater than or equal to the 338 * limit of the data buffer, the wrapped offset is set to 0. Thus, the 339 * current offset effectively "chases" the wrapped offset around the buffer. 340 * Schematically: 341 * 342 * base of data buffer ---> +------+--------------------+------+ 343 * | EPID | data | EPID | 344 * +------+--------+------+----+------+ 345 * | data | EPID | data | 346 * +---------------+------+-----------+ 347 * | data, cont. | 348 * +------+---------------------------+ 349 * | EPID | data | 350 * current offset ---> +------+---------------------------+ 351 * | invalid data | 352 * wrapped offset ---> +------+--------------------+------+ 353 * | EPID | data | EPID | 354 * +------+--------+------+----+------+ 355 * | data | EPID | data | 356 * +---------------+------+-----------+ 357 * : : 358 * . . 359 * . ... valid data ... . 360 * . . 361 * : : 362 * +------+-------------+------+------+ 363 * | EPID | data | EPID | data | 364 * +------+------------++------+------+ 365 * | data, cont. | leftover | 366 * limit of data buffer ---> +-------------------+--------------+ 367 * 368 * If the amount of requested buffer space exceeds the amount of space 369 * available between the current offset and the end of the buffer: 370 * 371 * (1) all words in the data buffer between the current offset and the limit 372 * of the data buffer (marked "leftover", above) are set to 373 * DTRACE_EPIDNONE 374 * 375 * (2) the wrapped offset is set to zero 376 * 377 * (3) the iteration process described above occurs until the wrapped offset 378 * is greater than the amount of desired space. 379 * 380 * The wrapped offset is implemented by (re-)using the inactive offset. 381 * In a "switch" buffer policy, the inactive offset stores the offset in 382 * the inactive buffer; in a "ring" buffer policy, it stores the wrapped 383 * offset. 384 * 385 * DTrace Scratch Buffering 386 * 387 * Some ECBs may wish to allocate dynamically-sized temporary scratch memory. 388 * To accommodate such requests easily, scratch memory may be allocated in 389 * the buffer beyond the current offset plus the needed memory of the current 390 * ECB. If there isn't sufficient room in the buffer for the requested amount 391 * of scratch space, the allocation fails and an error is generated. Scratch 392 * memory is tracked in the dtrace_mstate_t and is automatically freed when 393 * the ECB ceases processing. Note that ring buffers cannot allocate their 394 * scratch from the principal buffer -- lest they needlessly overwrite older, 395 * valid data. Ring buffers therefore have their own dedicated scratch buffer 396 * from which scratch is allocated. 397 */ 398 #define DTRACEBUF_RING 0x0001 /* bufpolicy set to "ring" */ 399 #define DTRACEBUF_FILL 0x0002 /* bufpolicy set to "fill" */ 400 #define DTRACEBUF_NOSWITCH 0x0004 /* do not switch buffer */ 401 #define DTRACEBUF_WRAPPED 0x0008 /* ring buffer has wrapped */ 402 #define DTRACEBUF_DROPPED 0x0010 /* drops occurred */ 403 #define DTRACEBUF_ERROR 0x0020 /* errors occurred */ 404 #define DTRACEBUF_FULL 0x0040 /* "fill" buffer is full */ 405 #define DTRACEBUF_CONSUMED 0x0080 /* buffer has been consumed */ 406 #define DTRACEBUF_INACTIVE 0x0100 /* buffer is not yet active */ 407 408 typedef struct dtrace_buffer { 409 uint64_t dtb_offset; /* current offset in buffer */ 410 uint64_t dtb_size; /* size of buffer */ 411 uint32_t dtb_flags; /* flags */ 412 uint32_t dtb_drops; /* number of drops */ 413 caddr_t dtb_tomax; /* active buffer */ 414 caddr_t dtb_xamot; /* inactive buffer */ 415 uint32_t dtb_xamot_flags; /* inactive flags */ 416 uint32_t dtb_xamot_drops; /* drops in inactive buffer */ 417 uint64_t dtb_xamot_offset; /* offset in inactive buffer */ 418 uint32_t dtb_errors; /* number of errors */ 419 uint32_t dtb_xamot_errors; /* errors in inactive buffer */ 420 #ifndef _LP64 421 uint64_t dtb_pad1; 422 #endif 423 } dtrace_buffer_t; 424 425 /* 426 * DTrace Aggregation Buffers 427 * 428 * Aggregation buffers use much of the same mechanism as described above 429 * ("DTrace Buffers"). However, because an aggregation is fundamentally a 430 * hash, there exists dynamic metadata associated with an aggregation buffer 431 * that is not associated with other kinds of buffers. This aggregation 432 * metadata is _only_ relevant for the in-kernel implementation of 433 * aggregations; it is not actually relevant to user-level consumers. To do 434 * this, we allocate dynamic aggregation data (hash keys and hash buckets) 435 * starting below the _limit_ of the buffer, and we allocate data from the 436 * _base_ of the buffer. When the aggregation buffer is copied out, _only_ the 437 * data is copied out; the metadata is simply discarded. Schematically, 438 * aggregation buffers look like: 439 * 440 * base of data buffer ---> +-------+------+-----------+-------+ 441 * | aggid | key | value | aggid | 442 * +-------+------+-----------+-------+ 443 * | key | 444 * +-------+-------+-----+------------+ 445 * | value | aggid | key | value | 446 * +-------+------++-----+------+-----+ 447 * | aggid | key | value | | 448 * +-------+------+-------------+ | 449 * | || | 450 * | || | 451 * | \/ | 452 * : : 453 * . . 454 * . . 455 * . . 456 * : : 457 * | /\ | 458 * | || +------------+ 459 * | || | | 460 * +---------------------+ | 461 * | hash keys | 462 * | (dtrace_aggkey structures) | 463 * | | 464 * +----------------------------------+ 465 * | hash buckets | 466 * | (dtrace_aggbuffer structure) | 467 * | | 468 * limit of data buffer ---> +----------------------------------+ 469 * 470 * 471 * As implied above, just as we assure that ECBs always store a constant 472 * amount of data, we assure that a given aggregation -- identified by its 473 * aggregation ID -- always stores data of a constant quantity and type. 474 * As with EPIDs, this allows the aggregation ID to serve as the metadata for a 475 * given record. 476 * 477 * Note that the size of the dtrace_aggkey structure must be sizeof (uintptr_t) 478 * aligned. (If this the structure changes such that this becomes false, an 479 * assertion will fail in dtrace_aggregate().) 480 */ 481 typedef struct dtrace_aggkey { 482 uint32_t dtak_hashval; /* hash value */ 483 uint32_t dtak_action:4; /* action -- 4 bits */ 484 uint32_t dtak_size:28; /* size -- 28 bits */ 485 caddr_t dtak_data; /* data pointer */ 486 struct dtrace_aggkey *dtak_next; /* next in hash chain */ 487 } dtrace_aggkey_t; 488 489 typedef struct dtrace_aggbuffer { 490 uintptr_t dtagb_hashsize; /* number of buckets */ 491 uintptr_t dtagb_free; /* free list of keys */ 492 dtrace_aggkey_t **dtagb_hash; /* hash table */ 493 } dtrace_aggbuffer_t; 494 495 /* 496 * DTrace Speculations 497 * 498 * Speculations have a per-CPU buffer and a global state. Once a speculation 499 * buffer has been comitted or discarded, it cannot be reused until all CPUs 500 * have taken the same action (commit or discard) on their respective 501 * speculative buffer. However, because DTrace probes may execute in arbitrary 502 * context, other CPUs cannot simply be cross-called at probe firing time to 503 * perform the necessary commit or discard. The speculation states thus 504 * optimize for the case that a speculative buffer is only active on one CPU at 505 * the time of a commit() or discard() -- for if this is the case, other CPUs 506 * need not take action, and the speculation is immediately available for 507 * reuse. If the speculation is active on multiple CPUs, it must be 508 * asynchronously cleaned -- potentially leading to a higher rate of dirty 509 * speculative drops. The speculation states are as follows: 510 * 511 * DTRACESPEC_INACTIVE <= Initial state; inactive speculation 512 * DTRACESPEC_ACTIVE <= Allocated, but not yet speculatively traced to 513 * DTRACESPEC_ACTIVEONE <= Speculatively traced to on one CPU 514 * DTRACESPEC_ACTIVEMANY <= Speculatively traced to on more than one CPU 515 * DTRACESPEC_COMMITTING <= Currently being commited on one CPU 516 * DTRACESPEC_COMMITTINGMANY <= Currently being commited on many CPUs 517 * DTRACESPEC_DISCARDING <= Currently being discarded on many CPUs 518 * 519 * The state transition diagram is as follows: 520 * 521 * +----------------------------------------------------------+ 522 * | | 523 * | +------------+ | 524 * | +-------------------| COMMITTING |<-----------------+ | 525 * | | +------------+ | | 526 * | | copied spec. ^ commit() on | | discard() on 527 * | | into principal | active CPU | | active CPU 528 * | | | commit() | | 529 * V V | | | 530 * +----------+ +--------+ +-----------+ 531 * | INACTIVE |---------------->| ACTIVE |--------------->| ACTIVEONE | 532 * +----------+ speculation() +--------+ speculate() +-----------+ 533 * ^ ^ | | | 534 * | | | discard() | | 535 * | | asynchronously | discard() on | | speculate() 536 * | | cleaned V inactive CPU | | on inactive 537 * | | +------------+ | | CPU 538 * | +-------------------| DISCARDING |<-----------------+ | 539 * | +------------+ | 540 * | asynchronously ^ | 541 * | copied spec. | discard() | 542 * | into principal +------------------------+ | 543 * | | V 544 * +----------------+ commit() +------------+ 545 * | COMMITTINGMANY |<----------------------------------| ACTIVEMANY | 546 * +----------------+ +------------+ 547 */ 548 typedef enum dtrace_speculation_state { 549 DTRACESPEC_INACTIVE = 0, 550 DTRACESPEC_ACTIVE, 551 DTRACESPEC_ACTIVEONE, 552 DTRACESPEC_ACTIVEMANY, 553 DTRACESPEC_COMMITTING, 554 DTRACESPEC_COMMITTINGMANY, 555 DTRACESPEC_DISCARDING 556 } dtrace_speculation_state_t; 557 558 typedef struct dtrace_speculation { 559 dtrace_speculation_state_t dtsp_state; /* current speculation state */ 560 int dtsp_cleaning; /* non-zero if being cleaned */ 561 dtrace_buffer_t *dtsp_buffer; /* speculative buffer */ 562 } dtrace_speculation_t; 563 564 /* 565 * DTrace Dynamic Variables 566 * 567 * The dynamic variable problem is obviously decomposed into two subproblems: 568 * allocating new dynamic storage, and freeing old dynamic storage. The 569 * presence of the second problem makes the first much more complicated -- or 570 * rather, the absence of the second renders the first trivial. This is the 571 * case with aggregations, for which there is effectively no deallocation of 572 * dynamic storage. (Or more accurately, all dynamic storage is deallocated 573 * when a snapshot is taken of the aggregation.) As DTrace dynamic variables 574 * allow for both dynamic allocation and dynamic deallocation, the 575 * implementation of dynamic variables is quite a bit more complicated than 576 * that of their aggregation kin. 577 * 578 * We observe that allocating new dynamic storage is tricky only because the 579 * size can vary -- the allocation problem is much easier if allocation sizes 580 * are uniform. We further observe that in D, the size of dynamic variables is 581 * actually _not_ dynamic -- dynamic variable sizes may be determined by static 582 * analysis of DIF text. (This is true even of putatively dynamically-sized 583 * objects like strings and stacks, the sizes of which are dictated by the 584 * "stringsize" and "stackframes" variables, respectively.) We exploit this by 585 * performing this analysis on all DIF before enabling any probes. For each 586 * dynamic load or store, we calculate the dynamically-allocated size plus the 587 * size of the dtrace_dynvar structure plus the storage required to key the 588 * data. For all DIF, we take the largest value and dub it the _chunksize_. 589 * We then divide dynamic memory into two parts: a hash table that is wide 590 * enough to have every chunk in its own bucket, and a larger region of equal 591 * chunksize units. Whenever we wish to dynamically allocate a variable, we 592 * always allocate a single chunk of memory. Depending on the uniformity of 593 * allocation, this will waste some amount of memory -- but it eliminates the 594 * non-determinism inherent in traditional heap fragmentation. 595 * 596 * Dynamic objects are allocated by storing a non-zero value to them; they are 597 * deallocated by storing a zero value to them. Dynamic variables are 598 * complicated enormously by being shared between CPUs. In particular, 599 * consider the following scenario: 600 * 601 * CPU A CPU B 602 * +---------------------------------+ +---------------------------------+ 603 * | | | | 604 * | allocates dynamic object a[123] | | | 605 * | by storing the value 345 to it | | | 606 * | ---------> | 607 * | | | wishing to load from object | 608 * | | | a[123], performs lookup in | 609 * | | | dynamic variable space | 610 * | <--------- | 611 * | deallocates object a[123] by | | | 612 * | storing 0 to it | | | 613 * | | | | 614 * | allocates dynamic object b[567] | | performs load from a[123] | 615 * | by storing the value 789 to it | | | 616 * : : : : 617 * . . . . 618 * 619 * This is obviously a race in the D program, but there are nonetheless only 620 * two valid values for CPU B's load from a[123]: 345 or 0. Most importantly, 621 * CPU B may _not_ see the value 789 for a[123]. 622 * 623 * There are essentially two ways to deal with this: 624 * 625 * (1) Explicitly spin-lock variables. That is, if CPU B wishes to load 626 * from a[123], it needs to lock a[123] and hold the lock for the 627 * duration that it wishes to manipulate it. 628 * 629 * (2) Avoid reusing freed chunks until it is known that no CPU is referring 630 * to them. 631 * 632 * The implementation of (1) is rife with complexity, because it requires the 633 * user of a dynamic variable to explicitly decree when they are done using it. 634 * Were all variables by value, this perhaps wouldn't be debilitating -- but 635 * dynamic variables of non-scalar types are tracked by reference. That is, if 636 * a dynamic variable is, say, a string, and that variable is to be traced to, 637 * say, the principal buffer, the DIF emulation code returns to the main 638 * dtrace_probe() loop a pointer to the underlying storage, not the contents of 639 * the storage. Further, code calling on DIF emulation would have to be aware 640 * that the DIF emulation has returned a reference to a dynamic variable that 641 * has been potentially locked. The variable would have to be unlocked after 642 * the main dtrace_probe() loop is finished with the variable, and the main 643 * dtrace_probe() loop would have to be careful to not call any further DIF 644 * emulation while the variable is locked to avoid deadlock. More generally, 645 * if one were to implement (1), DIF emulation code dealing with dynamic 646 * variables could only deal with one dynamic variable at a time (lest deadlock 647 * result). To sum, (1) exports too much subtlety to the users of dynamic 648 * variables -- increasing maintenance burden and imposing serious constraints 649 * on future DTrace development. 650 * 651 * The implementation of (2) is also complex, but the complexity is more 652 * manageable. We need to be sure that when a variable is deallocated, it is 653 * not placed on a traditional free list, but rather on a _dirty_ list. Once a 654 * variable is on a dirty list, it cannot be found by CPUs performing a 655 * subsequent lookup of the variable -- but it may still be in use by other 656 * CPUs. To assure that all CPUs that may be seeing the old variable have 657 * cleared out of probe context, a dtrace_sync() can be issued. Once the 658 * dtrace_sync() has completed, it can be known that all CPUs are done 659 * manipulating the dynamic variable -- the dirty list can be atomically 660 * appended to the free list. Unfortunately, there's a slight hiccup in this 661 * mechanism: dtrace_sync() may not be issued from probe context. The 662 * dtrace_sync() must be therefore issued asynchronously from non-probe 663 * context. For this we rely on the DTrace cleaner, a cyclic that runs at the 664 * "cleanrate" frequency. To ease this implementation, we define several chunk 665 * lists: 666 * 667 * - Dirty. Deallocated chunks, not yet cleaned. Not available. 668 * 669 * - Rinsing. Formerly dirty chunks that are currently being asynchronously 670 * cleaned. Not available, but will be shortly. Dynamic variable 671 * allocation may not spin or block for availability, however. 672 * 673 * - Clean. Clean chunks, ready for allocation -- but not on the free list. 674 * 675 * - Free. Available for allocation. 676 * 677 * Moreover, to avoid absurd contention, _each_ of these lists is implemented 678 * on a per-CPU basis. This is only for performance, not correctness; chunks 679 * may be allocated from another CPU's free list. The algorithm for allocation 680 * then is this: 681 * 682 * (1) Attempt to atomically allocate from current CPU's free list. If list 683 * is non-empty and allocation is successful, allocation is complete. 684 * 685 * (2) If the clean list is non-empty, atomically move it to the free list, 686 * and reattempt (1). 687 * 688 * (3) If the dynamic variable space is in the CLEAN state, look for free 689 * and clean lists on other CPUs by setting the current CPU to the next 690 * CPU, and reattempting (1). If the next CPU is the current CPU (that 691 * is, if all CPUs have been checked), atomically switch the state of 692 * the dynamic variable space based on the following: 693 * 694 * - If no free chunks were found and no dirty chunks were found, 695 * atomically set the state to EMPTY. 696 * 697 * - If dirty chunks were found, atomically set the state to DIRTY. 698 * 699 * - If rinsing chunks were found, atomically set the state to RINSING. 700 * 701 * (4) Based on state of dynamic variable space state, increment appropriate 702 * counter to indicate dynamic drops (if in EMPTY state) vs. dynamic 703 * dirty drops (if in DIRTY state) vs. dynamic rinsing drops (if in 704 * RINSING state). Fail the allocation. 705 * 706 * The cleaning cyclic operates with the following algorithm: for all CPUs 707 * with a non-empty dirty list, atomically move the dirty list to the rinsing 708 * list. Perform a dtrace_sync(). For all CPUs with a non-empty rinsing list, 709 * atomically move the rinsing list to the clean list. Perform another 710 * dtrace_sync(). By this point, all CPUs have seen the new clean list; the 711 * state of the dynamic variable space can be restored to CLEAN. 712 * 713 * There exist two final races that merit explanation. The first is a simple 714 * allocation race: 715 * 716 * CPU A CPU B 717 * +---------------------------------+ +---------------------------------+ 718 * | | | | 719 * | allocates dynamic object a[123] | | allocates dynamic object a[123] | 720 * | by storing the value 345 to it | | by storing the value 567 to it | 721 * | | | | 722 * : : : : 723 * . . . . 724 * 725 * Again, this is a race in the D program. It can be resolved by having a[123] 726 * hold the value 345 or a[123] hold the value 567 -- but it must be true that 727 * a[123] have only _one_ of these values. (That is, the racing CPUs may not 728 * put the same element twice on the same hash chain.) This is resolved 729 * simply: before the allocation is undertaken, the start of the new chunk's 730 * hash chain is noted. Later, after the allocation is complete, the hash 731 * chain is atomically switched to point to the new element. If this fails 732 * (because of either concurrent allocations or an allocation concurrent with a 733 * deletion), the newly allocated chunk is deallocated to the dirty list, and 734 * the whole process of looking up (and potentially allocating) the dynamic 735 * variable is reattempted. 736 * 737 * The final race is a simple deallocation race: 738 * 739 * CPU A CPU B 740 * +---------------------------------+ +---------------------------------+ 741 * | | | | 742 * | deallocates dynamic object | | deallocates dynamic object | 743 * | a[123] by storing the value 0 | | a[123] by storing the value 0 | 744 * | to it | | to it | 745 * | | | | 746 * : : : : 747 * . . . . 748 * 749 * Once again, this is a race in the D program, but it is one that we must 750 * handle without corrupting the underlying data structures. Because 751 * deallocations require the deletion of a chunk from the middle of a hash 752 * chain, we cannot use a single-word atomic operation to remove it. For this, 753 * we add a spin lock to the hash buckets that is _only_ used for deallocations 754 * (allocation races are handled as above). Further, this spin lock is _only_ 755 * held for the duration of the delete; before control is returned to the DIF 756 * emulation code, the hash bucket is unlocked. 757 */ 758 typedef struct dtrace_key { 759 uint64_t dttk_value; /* data value or data pointer */ 760 uint64_t dttk_size; /* 0 if by-val, >0 if by-ref */ 761 } dtrace_key_t; 762 763 typedef struct dtrace_tuple { 764 uint32_t dtt_nkeys; /* number of keys in tuple */ 765 uint32_t dtt_pad; /* padding */ 766 dtrace_key_t dtt_key[1]; /* array of tuple keys */ 767 } dtrace_tuple_t; 768 769 typedef struct dtrace_dynvar { 770 uint64_t dtdv_hashval; /* hash value -- 0 if free */ 771 struct dtrace_dynvar *dtdv_next; /* next on list or hash chain */ 772 void *dtdv_data; /* pointer to data */ 773 dtrace_tuple_t dtdv_tuple; /* tuple key */ 774 } dtrace_dynvar_t; 775 776 typedef enum dtrace_dynvar_op { 777 DTRACE_DYNVAR_ALLOC, 778 DTRACE_DYNVAR_NOALLOC, 779 DTRACE_DYNVAR_DEALLOC 780 } dtrace_dynvar_op_t; 781 782 typedef struct dtrace_dynhash { 783 dtrace_dynvar_t *dtdh_chain; /* hash chain for this bucket */ 784 uintptr_t dtdh_lock; /* deallocation lock */ 785 #ifdef _LP64 786 uintptr_t dtdh_pad[6]; /* pad to avoid false sharing */ 787 #else 788 uintptr_t dtdh_pad[14]; /* pad to avoid false sharing */ 789 #endif 790 } dtrace_dynhash_t; 791 792 typedef struct dtrace_dstate_percpu { 793 dtrace_dynvar_t *dtdsc_free; /* free list for this CPU */ 794 dtrace_dynvar_t *dtdsc_dirty; /* dirty list for this CPU */ 795 dtrace_dynvar_t *dtdsc_rinsing; /* rinsing list for this CPU */ 796 dtrace_dynvar_t *dtdsc_clean; /* clean list for this CPU */ 797 uint64_t dtdsc_drops; /* number of capacity drops */ 798 uint64_t dtdsc_dirty_drops; /* number of dirty drops */ 799 uint64_t dtdsc_rinsing_drops; /* number of rinsing drops */ 800 #ifdef _LP64 801 uint64_t dtdsc_pad; /* pad to avoid false sharing */ 802 #else 803 uint64_t dtdsc_pad[2]; /* pad to avoid false sharing */ 804 #endif 805 } dtrace_dstate_percpu_t; 806 807 typedef enum dtrace_dstate_state { 808 DTRACE_DSTATE_CLEAN = 0, 809 DTRACE_DSTATE_EMPTY, 810 DTRACE_DSTATE_DIRTY, 811 DTRACE_DSTATE_RINSING 812 } dtrace_dstate_state_t; 813 814 typedef struct dtrace_dstate { 815 void *dtds_base; /* base of dynamic var. space */ 816 size_t dtds_size; /* size of dynamic var. space */ 817 size_t dtds_hashsize; /* number of buckets in hash */ 818 size_t dtds_chunksize; /* size of each chunk */ 819 dtrace_dynhash_t *dtds_hash; /* pointer to hash table */ 820 dtrace_dstate_state_t dtds_state; /* current dynamic var. state */ 821 dtrace_dstate_percpu_t *dtds_percpu; /* per-CPU dyn. var. state */ 822 } dtrace_dstate_t; 823 824 /* 825 * DTrace Variable State 826 * 827 * The DTrace variable state tracks user-defined variables in its dtrace_vstate 828 * structure. Each DTrace consumer has exactly one dtrace_vstate structure, 829 * but some dtrace_vstate structures may exist without a corresponding DTrace 830 * consumer (see "DTrace Helpers", below). As described in <sys/dtrace.h>, 831 * user-defined variables can have one of three scopes: 832 * 833 * DIFV_SCOPE_GLOBAL => global scope 834 * DIFV_SCOPE_THREAD => thread-local scope (i.e. "self->" variables) 835 * DIFV_SCOPE_LOCAL => clause-local scope (i.e. "this->" variables) 836 * 837 * The variable state tracks variables by both their scope and their allocation 838 * type: 839 * 840 * - The dtvs_globals and dtvs_locals members each point to an array of 841 * dtrace_statvar structures. These structures contain both the variable 842 * metadata (dtrace_difv structures) and the underlying storage for all 843 * statically allocated variables, including statically allocated 844 * DIFV_SCOPE_GLOBAL variables and all DIFV_SCOPE_LOCAL variables. 845 * 846 * - The dtvs_tlocals member points to an array of dtrace_difv structures for 847 * DIFV_SCOPE_THREAD variables. As such, this array tracks _only_ the 848 * variable metadata for DIFV_SCOPE_THREAD variables; the underlying storage 849 * is allocated out of the dynamic variable space. 850 * 851 * - The dtvs_dynvars member is the dynamic variable state associated with the 852 * variable state. The dynamic variable state (described in "DTrace Dynamic 853 * Variables", above) tracks all DIFV_SCOPE_THREAD variables and all 854 * dynamically-allocated DIFV_SCOPE_GLOBAL variables. 855 */ 856 typedef struct dtrace_statvar { 857 uint64_t dtsv_data; /* data or pointer to it */ 858 size_t dtsv_size; /* size of pointed-to data */ 859 int dtsv_refcnt; /* reference count */ 860 dtrace_difv_t dtsv_var; /* variable metadata */ 861 } dtrace_statvar_t; 862 863 typedef struct dtrace_vstate { 864 dtrace_state_t *dtvs_state; /* back pointer to state */ 865 dtrace_statvar_t **dtvs_globals; /* statically-allocated glbls */ 866 int dtvs_nglobals; /* number of globals */ 867 dtrace_difv_t *dtvs_tlocals; /* thread-local metadata */ 868 int dtvs_ntlocals; /* number of thread-locals */ 869 dtrace_statvar_t **dtvs_locals; /* clause-local data */ 870 int dtvs_nlocals; /* number of clause-locals */ 871 dtrace_dstate_t dtvs_dynvars; /* dynamic variable state */ 872 } dtrace_vstate_t; 873 874 /* 875 * DTrace Machine State 876 * 877 * In the process of processing a fired probe, DTrace needs to track and/or 878 * cache some per-CPU state associated with that particular firing. This is 879 * state that is always discarded after the probe firing has completed, and 880 * much of it is not specific to any DTrace consumer, remaining valid across 881 * all ECBs. This state is tracked in the dtrace_mstate structure. 882 */ 883 #define DTRACE_MSTATE_ARGS 0x00000001 884 #define DTRACE_MSTATE_PROBE 0x00000002 885 #define DTRACE_MSTATE_EPID 0x00000004 886 #define DTRACE_MSTATE_TIMESTAMP 0x00000008 887 #define DTRACE_MSTATE_STACKDEPTH 0x00000010 888 #define DTRACE_MSTATE_CALLER 0x00000020 889 #define DTRACE_MSTATE_IPL 0x00000040 890 #define DTRACE_MSTATE_FLTOFFS 0x00000080 891 #define DTRACE_MSTATE_WALLTIMESTAMP 0x00000100 892 #define DTRACE_MSTATE_USTACKDEPTH 0x00000200 893 #define DTRACE_MSTATE_UCALLER 0x00000400 894 895 typedef struct dtrace_mstate { 896 uintptr_t dtms_scratch_base; /* base of scratch space */ 897 uintptr_t dtms_scratch_ptr; /* current scratch pointer */ 898 size_t dtms_scratch_size; /* scratch size */ 899 uint32_t dtms_present; /* variables that are present */ 900 uint64_t dtms_arg[5]; /* cached arguments */ 901 dtrace_epid_t dtms_epid; /* current EPID */ 902 uint64_t dtms_timestamp; /* cached timestamp */ 903 hrtime_t dtms_walltimestamp; /* cached wall timestamp */ 904 int dtms_stackdepth; /* cached stackdepth */ 905 int dtms_ustackdepth; /* cached ustackdepth */ 906 struct dtrace_probe *dtms_probe; /* current probe */ 907 uintptr_t dtms_caller; /* cached caller */ 908 uint64_t dtms_ucaller; /* cached user-level caller */ 909 int dtms_ipl; /* cached interrupt pri lev */ 910 int dtms_fltoffs; /* faulting DIFO offset */ 911 uintptr_t dtms_strtok; /* saved strtok() pointer */ 912 } dtrace_mstate_t; 913 914 #define DTRACE_COND_OWNER 0x1 915 #define DTRACE_COND_USERMODE 0x2 916 #define DTRACE_COND_ZONEOWNER 0x4 917 918 #define DTRACE_PROBEKEY_MAXDEPTH 8 /* max glob recursion depth */ 919 920 /* 921 * DTrace Activity 922 * 923 * Each DTrace consumer is in one of several states, which (for purposes of 924 * avoiding yet-another overloading of the noun "state") we call the current 925 * _activity_. The activity transitions on dtrace_go() (from DTRACIOCGO), on 926 * dtrace_stop() (from DTRACIOCSTOP) and on the exit() action. Activities may 927 * only transition in one direction; the activity transition diagram is a 928 * directed acyclic graph. The activity transition diagram is as follows: 929 * 930 * 931 * +----------+ +--------+ +--------+ 932 * | INACTIVE |------------------>| WARMUP |------------------>| ACTIVE | 933 * +----------+ dtrace_go(), +--------+ dtrace_go(), +--------+ 934 * before BEGIN | after BEGIN | | | 935 * | | | | 936 * exit() action | | | | 937 * from BEGIN ECB | | | | 938 * | | | | 939 * v | | | 940 * +----------+ exit() action | | | 941 * +-----------------------------| DRAINING |<-------------------+ | | 942 * | +----------+ | | 943 * | | | | 944 * | dtrace_stop(), | | | 945 * | before END | | | 946 * | | | | 947 * | v | | 948 * | +---------+ +----------+ | | 949 * | | STOPPED |<----------------| COOLDOWN |<----------------------+ | 950 * | +---------+ dtrace_stop(), +----------+ dtrace_stop(), | 951 * | after END before END | 952 * | | 953 * | +--------+ | 954 * +----------------------------->| KILLED |<--------------------------+ 955 * deadman timeout or +--------+ deadman timeout or 956 * killed consumer killed consumer 957 * 958 * Note that once a DTrace consumer has stopped tracing, there is no way to 959 * restart it; if a DTrace consumer wishes to restart tracing, it must reopen 960 * the DTrace pseudodevice. 961 */ 962 typedef enum dtrace_activity { 963 DTRACE_ACTIVITY_INACTIVE = 0, /* not yet running */ 964 DTRACE_ACTIVITY_WARMUP, /* while starting */ 965 DTRACE_ACTIVITY_ACTIVE, /* running */ 966 DTRACE_ACTIVITY_DRAINING, /* before stopping */ 967 DTRACE_ACTIVITY_COOLDOWN, /* while stopping */ 968 DTRACE_ACTIVITY_STOPPED, /* after stopping */ 969 DTRACE_ACTIVITY_KILLED /* killed */ 970 } dtrace_activity_t; 971 972 /* 973 * DTrace Helper Implementation 974 * 975 * A description of the helper architecture may be found in <sys/dtrace.h>. 976 * Each process contains a pointer to its helpers in its p_dtrace_helpers 977 * member. This is a pointer to a dtrace_helpers structure, which contains an 978 * array of pointers to dtrace_helper structures, helper variable state (shared 979 * among a process's helpers) and a generation count. (The generation count is 980 * used to provide an identifier when a helper is added so that it may be 981 * subsequently removed.) The dtrace_helper structure is self-explanatory, 982 * containing pointers to the objects needed to execute the helper. Note that 983 * helpers are _duplicated_ across fork(2), and destroyed on exec(2). No more 984 * than dtrace_helpers_max are allowed per-process. 985 */ 986 #define DTRACE_HELPER_ACTION_USTACK 0 987 #define DTRACE_NHELPER_ACTIONS 1 988 989 typedef struct dtrace_helper_action { 990 dtrace_difo_t *dthp_predicate; /* helper action predicate */ 991 int dthp_nactions; /* number of actions */ 992 dtrace_difo_t **dthp_actions; /* array of actions */ 993 int dthp_generation; /* helper action generation */ 994 struct dtrace_helper_action *dthp_next; /* next helper action */ 995 } dtrace_helper_action_t; 996 997 typedef struct dtrace_helper_provider { 998 dof_helper_t dthp_prov; /* DOF w/ provider and probes */ 999 uint32_t dthp_ref; /* reference count */ 1000 } dtrace_helper_provider_t; 1001 1002 typedef struct dtrace_helpers { 1003 dtrace_helper_action_t **dthps_actions; /* array of helper actions */ 1004 dtrace_vstate_t dthps_vstate; /* helper action var. state */ 1005 dtrace_helper_provider_t **dthps_provs; /* array of providers */ 1006 uint_t dthps_nprovs; /* count of providers */ 1007 int dthps_generation; /* current generation */ 1008 pid_t dthps_pid; /* pid of associated proc */ 1009 int dthps_deferred; /* helper in deferred list */ 1010 struct dtrace_helpers *dthps_next; /* next pointer */ 1011 struct dtrace_helpers *dthps_prev; /* prev pointer */ 1012 } dtrace_helpers_t; 1013 1014 /* 1015 * DTrace Helper Action Tracing 1016 * 1017 * Debugging helper actions can be arduous. To ease the development and 1018 * debugging of helpers, DTrace contains a tracing-framework-within-a-tracing- 1019 * framework: helper tracing. If dtrace_helptrace_enabled is non-zero (which 1020 * it is by default on DEBUG kernels), all helper activity will be traced to a 1021 * global, in-kernel ring buffer. Each entry includes a pointer to the specific 1022 * helper, the location within the helper, and a trace of all local variables. 1023 * The ring buffer may be displayed in a human-readable format with the 1024 * ::dtrace_helptrace mdb(1) dcmd. 1025 */ 1026 #define DTRACE_HELPTRACE_NEXT (-1) 1027 #define DTRACE_HELPTRACE_DONE (-2) 1028 #define DTRACE_HELPTRACE_ERR (-3) 1029 1030 typedef struct dtrace_helptrace { 1031 dtrace_helper_action_t *dtht_helper; /* helper action */ 1032 int dtht_where; /* where in helper action */ 1033 int dtht_nlocals; /* number of locals */ 1034 int dtht_fault; /* type of fault (if any) */ 1035 int dtht_fltoffs; /* DIF offset */ 1036 uint64_t dtht_illval; /* faulting value */ 1037 uint64_t dtht_locals[1]; /* local variables */ 1038 } dtrace_helptrace_t; 1039 1040 /* 1041 * DTrace Credentials 1042 * 1043 * In probe context, we have limited flexibility to examine the credentials 1044 * of the DTrace consumer that created a particular enabling. We use 1045 * the Least Privilege interfaces to cache the consumer's cred pointer and 1046 * some facts about that credential in a dtrace_cred_t structure. These 1047 * can limit the consumer's breadth of visibility and what actions the 1048 * consumer may take. 1049 */ 1050 #define DTRACE_CRV_ALLPROC 0x01 1051 #define DTRACE_CRV_KERNEL 0x02 1052 #define DTRACE_CRV_ALLZONE 0x04 1053 1054 #define DTRACE_CRV_ALL (DTRACE_CRV_ALLPROC | DTRACE_CRV_KERNEL | \ 1055 DTRACE_CRV_ALLZONE) 1056 1057 #define DTRACE_CRA_PROC 0x0001 1058 #define DTRACE_CRA_PROC_CONTROL 0x0002 1059 #define DTRACE_CRA_PROC_DESTRUCTIVE_ALLUSER 0x0004 1060 #define DTRACE_CRA_PROC_DESTRUCTIVE_ALLZONE 0x0008 1061 #define DTRACE_CRA_PROC_DESTRUCTIVE_CREDCHG 0x0010 1062 #define DTRACE_CRA_KERNEL 0x0020 1063 #define DTRACE_CRA_KERNEL_DESTRUCTIVE 0x0040 1064 1065 #define DTRACE_CRA_ALL (DTRACE_CRA_PROC | \ 1066 DTRACE_CRA_PROC_CONTROL | \ 1067 DTRACE_CRA_PROC_DESTRUCTIVE_ALLUSER | \ 1068 DTRACE_CRA_PROC_DESTRUCTIVE_ALLZONE | \ 1069 DTRACE_CRA_PROC_DESTRUCTIVE_CREDCHG | \ 1070 DTRACE_CRA_KERNEL | \ 1071 DTRACE_CRA_KERNEL_DESTRUCTIVE) 1072 1073 typedef struct dtrace_cred { 1074 cred_t *dcr_cred; 1075 uint8_t dcr_destructive; 1076 uint8_t dcr_visible; 1077 uint16_t dcr_action; 1078 } dtrace_cred_t; 1079 1080 /* 1081 * DTrace Consumer State 1082 * 1083 * Each DTrace consumer has an associated dtrace_state structure that contains 1084 * its in-kernel DTrace state -- including options, credentials, statistics and 1085 * pointers to ECBs, buffers, speculations and formats. A dtrace_state 1086 * structure is also allocated for anonymous enablings. When anonymous state 1087 * is grabbed, the grabbing consumers dts_anon pointer is set to the grabbed 1088 * dtrace_state structure. 1089 */ 1090 struct dtrace_state { 1091 dev_t dts_dev; /* device */ 1092 int dts_necbs; /* total number of ECBs */ 1093 dtrace_ecb_t **dts_ecbs; /* array of ECBs */ 1094 dtrace_epid_t dts_epid; /* next EPID to allocate */ 1095 size_t dts_needed; /* greatest needed space */ 1096 struct dtrace_state *dts_anon; /* anon. state, if grabbed */ 1097 dtrace_activity_t dts_activity; /* current activity */ 1098 dtrace_vstate_t dts_vstate; /* variable state */ 1099 dtrace_buffer_t *dts_buffer; /* principal buffer */ 1100 dtrace_buffer_t *dts_aggbuffer; /* aggregation buffer */ 1101 dtrace_speculation_t *dts_speculations; /* speculation array */ 1102 int dts_nspeculations; /* number of speculations */ 1103 int dts_naggregations; /* number of aggregations */ 1104 dtrace_aggregation_t **dts_aggregations; /* aggregation array */ 1105 vmem_t *dts_aggid_arena; /* arena for aggregation IDs */ 1106 uint64_t dts_errors; /* total number of errors */ 1107 uint32_t dts_speculations_busy; /* number of spec. busy */ 1108 uint32_t dts_speculations_unavail; /* number of spec unavail */ 1109 uint32_t dts_stkstroverflows; /* stack string tab overflows */ 1110 uint32_t dts_dblerrors; /* errors in ERROR probes */ 1111 uint32_t dts_reserve; /* space reserved for END */ 1112 hrtime_t dts_laststatus; /* time of last status */ 1113 cyclic_id_t dts_cleaner; /* cleaning cyclic */ 1114 cyclic_id_t dts_deadman; /* deadman cyclic */ 1115 hrtime_t dts_alive; /* time last alive */ 1116 char dts_speculates; /* boolean: has speculations */ 1117 char dts_destructive; /* boolean: has dest. actions */ 1118 int dts_nformats; /* number of formats */ 1119 char **dts_formats; /* format string array */ 1120 dtrace_optval_t dts_options[DTRACEOPT_MAX]; /* options */ 1121 dtrace_cred_t dts_cred; /* credentials */ 1122 size_t dts_nretained; /* number of retained enabs */ 1123 }; 1124 1125 struct dtrace_provider { 1126 dtrace_pattr_t dtpv_attr; /* provider attributes */ 1127 dtrace_ppriv_t dtpv_priv; /* provider privileges */ 1128 dtrace_pops_t dtpv_pops; /* provider operations */ 1129 char *dtpv_name; /* provider name */ 1130 void *dtpv_arg; /* provider argument */ 1131 uint_t dtpv_defunct; /* boolean: defunct provider */ 1132 struct dtrace_provider *dtpv_next; /* next provider */ 1133 }; 1134 1135 struct dtrace_meta { 1136 dtrace_mops_t dtm_mops; /* meta provider operations */ 1137 char *dtm_name; /* meta provider name */ 1138 void *dtm_arg; /* meta provider user arg */ 1139 uint64_t dtm_count; /* no. of associated provs. */ 1140 }; 1141 1142 /* 1143 * DTrace Enablings 1144 * 1145 * A dtrace_enabling structure is used to track a collection of ECB 1146 * descriptions -- before they have been turned into actual ECBs. This is 1147 * created as a result of DOF processing, and is generally used to generate 1148 * ECBs immediately thereafter. However, enablings are also generally 1149 * retained should the probes they describe be created at a later time; as 1150 * each new module or provider registers with the framework, the retained 1151 * enablings are reevaluated, with any new match resulting in new ECBs. To 1152 * prevent probes from being matched more than once, the enabling tracks the 1153 * last probe generation matched, and only matches probes from subsequent 1154 * generations. 1155 */ 1156 typedef struct dtrace_enabling { 1157 dtrace_ecbdesc_t **dten_desc; /* all ECB descriptions */ 1158 int dten_ndesc; /* number of ECB descriptions */ 1159 int dten_maxdesc; /* size of ECB array */ 1160 dtrace_vstate_t *dten_vstate; /* associated variable state */ 1161 dtrace_genid_t dten_probegen; /* matched probe generation */ 1162 dtrace_ecbdesc_t *dten_current; /* current ECB description */ 1163 int dten_error; /* current error value */ 1164 int dten_primed; /* boolean: set if primed */ 1165 struct dtrace_enabling *dten_prev; /* previous enabling */ 1166 struct dtrace_enabling *dten_next; /* next enabling */ 1167 } dtrace_enabling_t; 1168 1169 /* 1170 * DTrace Anonymous Enablings 1171 * 1172 * Anonymous enablings are DTrace enablings that are not associated with a 1173 * controlling process, but rather derive their enabling from DOF stored as 1174 * properties in the dtrace.conf file. If there is an anonymous enabling, a 1175 * DTrace consumer state and enabling are created on attach. The state may be 1176 * subsequently grabbed by the first consumer specifying the "grabanon" 1177 * option. As long as an anonymous DTrace enabling exists, dtrace(7D) will 1178 * refuse to unload. 1179 */ 1180 typedef struct dtrace_anon { 1181 dtrace_state_t *dta_state; /* DTrace consumer state */ 1182 dtrace_enabling_t *dta_enabling; /* pointer to enabling */ 1183 processorid_t dta_beganon; /* which CPU BEGIN ran on */ 1184 } dtrace_anon_t; 1185 1186 /* 1187 * DTrace Error Debugging 1188 */ 1189 #ifdef DEBUG 1190 #define DTRACE_ERRDEBUG 1191 #endif 1192 1193 #ifdef DTRACE_ERRDEBUG 1194 1195 typedef struct dtrace_errhash { 1196 const char *dter_msg; /* error message */ 1197 int dter_count; /* number of times seen */ 1198 } dtrace_errhash_t; 1199 1200 #define DTRACE_ERRHASHSZ 256 /* must be > number of err msgs */ 1201 1202 #endif /* DTRACE_ERRDEBUG */ 1203 1204 /* 1205 * DTrace Toxic Ranges 1206 * 1207 * DTrace supports safe loads from probe context; if the address turns out to 1208 * be invalid, a bit will be set by the kernel indicating that DTrace 1209 * encountered a memory error, and DTrace will propagate the error to the user 1210 * accordingly. However, there may exist some regions of memory in which an 1211 * arbitrary load can change system state, and from which it is impossible to 1212 * recover from such a load after it has been attempted. Examples of this may 1213 * include memory in which programmable I/O registers are mapped (for which a 1214 * read may have some implications for the device) or (in the specific case of 1215 * UltraSPARC-I and -II) the virtual address hole. The platform is required 1216 * to make DTrace aware of these toxic ranges; DTrace will then check that 1217 * target addresses are not in a toxic range before attempting to issue a 1218 * safe load. 1219 */ 1220 typedef struct dtrace_toxrange { 1221 uintptr_t dtt_base; /* base of toxic range */ 1222 uintptr_t dtt_limit; /* limit of toxic range */ 1223 } dtrace_toxrange_t; 1224 1225 extern uint64_t dtrace_getarg(int, int); 1226 extern greg_t dtrace_getfp(void); 1227 extern int dtrace_getipl(void); 1228 extern uintptr_t dtrace_caller(int); 1229 extern uint32_t dtrace_cas32(uint32_t *, uint32_t, uint32_t); 1230 extern void *dtrace_casptr(void *, void *, void *); 1231 extern void dtrace_copyin(uintptr_t, uintptr_t, size_t); 1232 extern void dtrace_copyinstr(uintptr_t, uintptr_t, size_t); 1233 extern void dtrace_copyout(uintptr_t, uintptr_t, size_t); 1234 extern void dtrace_copyoutstr(uintptr_t, uintptr_t, size_t); 1235 extern void dtrace_getpcstack(pc_t *, int, int, uint32_t *); 1236 extern ulong_t dtrace_getreg(struct regs *, uint_t); 1237 extern int dtrace_getstackdepth(int); 1238 extern void dtrace_getupcstack(uint64_t *, int); 1239 extern void dtrace_getufpstack(uint64_t *, uint64_t *, int); 1240 extern int dtrace_getustackdepth(void); 1241 extern uintptr_t dtrace_fulword(void *); 1242 extern uint8_t dtrace_fuword8(void *); 1243 extern uint16_t dtrace_fuword16(void *); 1244 extern uint32_t dtrace_fuword32(void *); 1245 extern uint64_t dtrace_fuword64(void *); 1246 extern void dtrace_probe_error(dtrace_state_t *, dtrace_epid_t, int, int, 1247 int, uintptr_t); 1248 extern int dtrace_assfail(const char *, const char *, int); 1249 extern int dtrace_attached(void); 1250 extern hrtime_t dtrace_gethrestime(); 1251 1252 #ifdef __sparc 1253 extern void dtrace_flush_windows(void); 1254 extern void dtrace_flush_user_windows(void); 1255 extern uint_t dtrace_getotherwin(void); 1256 extern uint_t dtrace_getfprs(void); 1257 #else 1258 extern void dtrace_copy(uintptr_t, uintptr_t, size_t); 1259 extern void dtrace_copystr(uintptr_t, uintptr_t, size_t); 1260 #endif 1261 1262 /* 1263 * DTrace Assertions 1264 * 1265 * DTrace calls ASSERT from probe context. To assure that a failed ASSERT 1266 * does not induce a markedly more catastrophic failure (e.g., one from which 1267 * a dump cannot be gleaned), DTrace must define its own ASSERT to be one that 1268 * may safely be called from probe context. This header file must thus be 1269 * included by any DTrace component that calls ASSERT from probe context, and 1270 * _only_ by those components. (The only exception to this is kernel 1271 * debugging infrastructure at user-level that doesn't depend on calling 1272 * ASSERT.) 1273 */ 1274 #undef ASSERT 1275 #ifdef DEBUG 1276 #define ASSERT(EX) ((void)((EX) || \ 1277 dtrace_assfail(#EX, __FILE__, __LINE__))) 1278 #else 1279 #define ASSERT(X) ((void)0) 1280 #endif 1281 1282 #ifdef __cplusplus 1283 } 1284 #endif 1285 1286 #endif /* _SYS_DTRACE_IMPL_H */ 1287