/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2006 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ #ifndef _SYS_DTRACE_IMPL_H #define _SYS_DTRACE_IMPL_H /* #pragma ident "@(#)dtrace_impl.h 1.21 06/05/19 SMI" */ #ifdef __cplusplus extern "C" { #endif /* * DTrace Dynamic Tracing Software: Kernel Implementation Interfaces * * Note: The contents of this file are private to the implementation of the * Solaris system and DTrace subsystem and are subject to change at any time * without notice. Applications and drivers using these interfaces will fail * to run on future releases. These interfaces should not be used for any * purpose except those expressly outlined in dtrace(7D) and libdtrace(3LIB). * Please refer to the "Solaris Dynamic Tracing Guide" for more information. */ #include <sys/dtrace.h> /* * DTrace Implementation Constants and Typedefs */ #define DTRACE_MAXPROPLEN 128 #define DTRACE_DYNVAR_CHUNKSIZE 256 struct dtrace_probe; struct dtrace_ecb; struct dtrace_predicate; struct dtrace_action; struct dtrace_provider; struct dtrace_state; typedef struct dtrace_probe dtrace_probe_t; typedef struct dtrace_ecb dtrace_ecb_t; typedef struct dtrace_predicate dtrace_predicate_t; typedef struct dtrace_action dtrace_action_t; typedef struct dtrace_provider dtrace_provider_t; typedef struct dtrace_meta dtrace_meta_t; typedef struct dtrace_state dtrace_state_t; typedef uint32_t dtrace_optid_t; typedef uint32_t dtrace_specid_t; typedef uint64_t dtrace_genid_t; /* * DTrace Probes * * The probe is the fundamental unit of the DTrace architecture. Probes are * created by DTrace providers, and managed by the DTrace framework. A probe * is identified by a unique <provider, module, function, name> tuple, and has * a unique probe identifier assigned to it. (Some probes are not associated * with a specific point in text; these are called _unanchored probes_ and have * no module or function associated with them.) Probes are represented as a * dtrace_probe structure. To allow quick lookups based on each element of the * probe tuple, probes are hashed by each of provider, module, function and * name. (If a lookup is performed based on a regular expression, a * dtrace_probekey is prepared, and a linear search is performed.) Each probe * is additionally pointed to by a linear array indexed by its identifier. The * identifier is the provider's mechanism for indicating to the DTrace * framework that a probe has fired: the identifier is passed as the first * argument to dtrace_probe(), where it is then mapped into the corresponding * dtrace_probe structure. From the dtrace_probe structure, dtrace_probe() can * iterate over the probe's list of enabling control blocks; see "DTrace * Enabling Control Blocks", below.) */ struct dtrace_probe { dtrace_id_t dtpr_id; /* probe identifier */ dtrace_ecb_t *dtpr_ecb; /* ECB list; see below */ dtrace_ecb_t *dtpr_ecb_last; /* last ECB in list */ void *dtpr_arg; /* provider argument */ dtrace_cacheid_t dtpr_predcache; /* predicate cache ID */ int dtpr_aframes; /* artificial frames */ dtrace_provider_t *dtpr_provider; /* pointer to provider */ char *dtpr_mod; /* probe's module name */ char *dtpr_func; /* probe's function name */ char *dtpr_name; /* probe's name */ dtrace_probe_t *dtpr_nextmod; /* next in module hash */ dtrace_probe_t *dtpr_prevmod; /* previous in module hash */ dtrace_probe_t *dtpr_nextfunc; /* next in function hash */ dtrace_probe_t *dtpr_prevfunc; /* previous in function hash */ dtrace_probe_t *dtpr_nextname; /* next in name hash */ dtrace_probe_t *dtpr_prevname; /* previous in name hash */ dtrace_genid_t dtpr_gen; /* probe generation ID */ }; typedef int dtrace_probekey_f(const char *, const char *, int); typedef struct dtrace_probekey { const char *dtpk_prov; /* provider name to match */ dtrace_probekey_f *dtpk_pmatch; /* provider matching function */ const char *dtpk_mod; /* module name to match */ dtrace_probekey_f *dtpk_mmatch; /* module matching function */ const char *dtpk_func; /* func name to match */ dtrace_probekey_f *dtpk_fmatch; /* func matching function */ const char *dtpk_name; /* name to match */ dtrace_probekey_f *dtpk_nmatch; /* name matching function */ dtrace_id_t dtpk_id; /* identifier to match */ } dtrace_probekey_t; typedef struct dtrace_hashbucket { struct dtrace_hashbucket *dthb_next; /* next on hash chain */ dtrace_probe_t *dthb_chain; /* chain of probes */ int dthb_len; /* number of probes here */ } dtrace_hashbucket_t; typedef struct dtrace_hash { dtrace_hashbucket_t **dth_tab; /* hash table */ int dth_size; /* size of hash table */ int dth_mask; /* mask to index into table */ int dth_nbuckets; /* total number of buckets */ uintptr_t dth_nextoffs; /* offset of next in probe */ uintptr_t dth_prevoffs; /* offset of prev in probe */ uintptr_t dth_stroffs; /* offset of str in probe */ } dtrace_hash_t; /* * DTrace Enabling Control Blocks * * When a provider wishes to fire a probe, it calls into dtrace_probe(), * passing the probe identifier as the first argument. As described above, * dtrace_probe() maps the identifier into a pointer to a dtrace_probe_t * structure. This structure contains information about the probe, and a * pointer to the list of Enabling Control Blocks (ECBs). Each ECB points to * DTrace consumer state, and contains an optional predicate, and a list of * actions. (Shown schematically below.) The ECB abstraction allows a single * probe to be multiplexed across disjoint consumers, or across disjoint * enablings of a single probe within one consumer. * * Enabling Control Block * dtrace_ecb_t * +------------------------+ * | dtrace_epid_t ---------+--------------> Enabled Probe ID (EPID) * | dtrace_state_t * ------+--------------> State associated with this ECB * | dtrace_predicate_t * --+---------+ * | dtrace_action_t * -----+----+ | * | dtrace_ecb_t * ---+ | | | Predicate (if any) * +-------------------+----+ | | dtrace_predicate_t * | | +---> +--------------------+ * | | | dtrace_difo_t * ---+----> DIFO * | | +--------------------+ * | | * Next ECB | | Action * (if any) | | dtrace_action_t * : +--> +-------------------+ * : | dtrace_actkind_t -+------> kind * v | dtrace_difo_t * --+------> DIFO (if any) * | dtrace_recdesc_t -+------> record descr. * | dtrace_action_t * +------+ * +-------------------+ | * | Next action * +-------------------------------+ (if any) * | * | Action * | dtrace_action_t * +--> +-------------------+ * | dtrace_actkind_t -+------> kind * | dtrace_difo_t * --+------> DIFO (if any) * | dtrace_action_t * +------+ * +-------------------+ | * | Next action * +-------------------------------+ (if any) * | * : * v * * * dtrace_probe() iterates over the ECB list. If the ECB needs less space * than is available in the principal buffer, the ECB is processed: if the * predicate is non-NULL, the DIF object is executed. If the result is * non-zero, the action list is processed, with each action being executed * accordingly. When the action list has been completely executed, processing * advances to the next ECB. processing advances to the next ECB. If the * result is non-zero; For each ECB, it first determines the The ECB * abstraction allows disjoint consumers to multiplex on single probes. */ struct dtrace_ecb { dtrace_epid_t dte_epid; /* enabled probe ID */ uint32_t dte_alignment; /* required alignment */ size_t dte_needed; /* bytes needed */ size_t dte_size; /* total size of payload */ dtrace_predicate_t *dte_predicate; /* predicate, if any */ dtrace_action_t *dte_action; /* actions, if any */ dtrace_ecb_t *dte_next; /* next ECB on probe */ dtrace_state_t *dte_state; /* pointer to state */ uint32_t dte_cond; /* security condition */ dtrace_probe_t *dte_probe; /* pointer to probe */ dtrace_action_t *dte_action_last; /* last action on ECB */ uint64_t dte_uarg; /* library argument */ }; struct dtrace_predicate { dtrace_difo_t *dtp_difo; /* DIF object */ dtrace_cacheid_t dtp_cacheid; /* cache identifier */ int dtp_refcnt; /* reference count */ }; struct dtrace_action { dtrace_actkind_t dta_kind; /* kind of action */ uint16_t dta_intuple; /* boolean: in aggregation */ uint32_t dta_refcnt; /* reference count */ dtrace_difo_t *dta_difo; /* pointer to DIFO */ dtrace_recdesc_t dta_rec; /* record description */ dtrace_action_t *dta_prev; /* previous action */ dtrace_action_t *dta_next; /* next action */ }; typedef struct dtrace_aggregation { dtrace_action_t dtag_action; /* action; must be first */ dtrace_aggid_t dtag_id; /* identifier */ dtrace_ecb_t *dtag_ecb; /* corresponding ECB */ dtrace_action_t *dtag_first; /* first action in tuple */ uint32_t dtag_base; /* base of aggregation */ uint8_t dtag_hasarg; /* boolean: has argument */ uint64_t dtag_initial; /* initial value */ void (*dtag_aggregate)(uint64_t *, uint64_t, uint64_t); } dtrace_aggregation_t; /* * DTrace Buffers * * Principal buffers, aggregation buffers, and speculative buffers are all * managed with the dtrace_buffer structure. By default, this structure * includes twin data buffers -- dtb_tomax and dtb_xamot -- that serve as the * active and passive buffers, respectively. For speculative buffers, * dtb_xamot will be NULL; for "ring" and "fill" buffers, dtb_xamot will point * to a scratch buffer. For all buffer types, the dtrace_buffer structure is * always allocated on a per-CPU basis; a single dtrace_buffer structure is * never shared among CPUs. (That is, there is never true sharing of the * dtrace_buffer structure; to prevent false sharing of the structure, it must * always be aligned to the coherence granularity -- generally 64 bytes.) * * One of the critical design decisions of DTrace is that a given ECB always * stores the same quantity and type of data. This is done to assure that the * only metadata required for an ECB's traced data is the EPID. That is, from * the EPID, the consumer can determine the data layout. (The data buffer * layout is shown schematically below.) By assuring that one can determine * data layout from the EPID, the metadata stream can be separated from the * data stream -- simplifying the data stream enormously. * * base of data buffer ---> +------+--------------------+------+ * | EPID | data | EPID | * +------+--------+------+----+------+ * | data | EPID | data | * +---------------+------+-----------+ * | data, cont. | * +------+--------------------+------+ * | EPID | data | | * +------+--------------------+ | * | || | * | || | * | \/ | * : : * . . * . . * . . * : : * | | * limit of data buffer ---> +----------------------------------+ * * When evaluating an ECB, dtrace_probe() determines if the ECB's needs of the * principal buffer (both scratch and payload) exceed the available space. If * the ECB's needs exceed available space (and if the principal buffer policy * is the default "switch" policy), the ECB is dropped, the buffer's drop count * is incremented, and processing advances to the next ECB. If the ECB's needs * can be met with the available space, the ECB is processed, but the offset in * the principal buffer is only advanced if the ECB completes processing * without error. * * When a buffer is to be switched (either because the buffer is the principal * buffer with a "switch" policy or because it is an aggregation buffer), a * cross call is issued to the CPU associated with the buffer. In the cross * call context, interrupts are disabled, and the active and the inactive * buffers are atomically switched. This involves switching the data pointers, * copying the various state fields (offset, drops, errors, etc.) into their * inactive equivalents, and clearing the state fields. Because interrupts are * disabled during this procedure, the switch is guaranteed to appear atomic to * dtrace_probe(). * * DTrace Ring Buffering * * To process a ring buffer correctly, one must know the oldest valid record. * Processing starts at the oldest record in the buffer and continues until * the end of the buffer is reached. Processing then resumes starting with * the record stored at offset 0 in the buffer, and continues until the * youngest record is processed. If trace records are of a fixed-length, * determining the oldest record is trivial: * * - If the ring buffer has not wrapped, the oldest record is the record * stored at offset 0. * * - If the ring buffer has wrapped, the oldest record is the record stored * at the current offset. * * With variable length records, however, just knowing the current offset * doesn't suffice for determining the oldest valid record: assuming that one * allows for arbitrary data, one has no way of searching forward from the * current offset to find the oldest valid record. (That is, one has no way * of separating data from metadata.) It would be possible to simply refuse to * process any data in the ring buffer between the current offset and the * limit, but this leaves (potentially) an enormous amount of otherwise valid * data unprocessed. * * To effect ring buffering, we track two offsets in the buffer: the current * offset and the _wrapped_ offset. If a request is made to reserve some * amount of data, and the buffer has wrapped, the wrapped offset is * incremented until the wrapped offset minus the current offset is greater * than or equal to the reserve request. This is done by repeatedly looking * up the ECB corresponding to the EPID at the current wrapped offset, and * incrementing the wrapped offset by the size of the data payload * corresponding to that ECB. If this offset is greater than or equal to the * limit of the data buffer, the wrapped offset is set to 0. Thus, the * current offset effectively "chases" the wrapped offset around the buffer. * Schematically: * * base of data buffer ---> +------+--------------------+------+ * | EPID | data | EPID | * +------+--------+------+----+------+ * | data | EPID | data | * +---------------+------+-----------+ * | data, cont. | * +------+---------------------------+ * | EPID | data | * current offset ---> +------+---------------------------+ * | invalid data | * wrapped offset ---> +------+--------------------+------+ * | EPID | data | EPID | * +------+--------+------+----+------+ * | data | EPID | data | * +---------------+------+-----------+ * : : * . . * . ... valid data ... . * . . * : : * +------+-------------+------+------+ * | EPID | data | EPID | data | * +------+------------++------+------+ * | data, cont. | leftover | * limit of data buffer ---> +-------------------+--------------+ * * If the amount of requested buffer space exceeds the amount of space * available between the current offset and the end of the buffer: * * (1) all words in the data buffer between the current offset and the limit * of the data buffer (marked "leftover", above) are set to * DTRACE_EPIDNONE * * (2) the wrapped offset is set to zero * * (3) the iteration process described above occurs until the wrapped offset * is greater than the amount of desired space. * * The wrapped offset is implemented by (re-)using the inactive offset. * In a "switch" buffer policy, the inactive offset stores the offset in * the inactive buffer; in a "ring" buffer policy, it stores the wrapped * offset. * * DTrace Scratch Buffering * * Some ECBs may wish to allocate dynamically-sized temporary scratch memory. * To accommodate such requests easily, scratch memory may be allocated in * the buffer beyond the current offset plus the needed memory of the current * ECB. If there isn't sufficient room in the buffer for the requested amount * of scratch space, the allocation fails and an error is generated. Scratch * memory is tracked in the dtrace_mstate_t and is automatically freed when * the ECB ceases processing. Note that ring buffers cannot allocate their * scratch from the principal buffer -- lest they needlessly overwrite older, * valid data. Ring buffers therefore have their own dedicated scratch buffer * from which scratch is allocated. */ #define DTRACEBUF_RING 0x0001 /* bufpolicy set to "ring" */ #define DTRACEBUF_FILL 0x0002 /* bufpolicy set to "fill" */ #define DTRACEBUF_NOSWITCH 0x0004 /* do not switch buffer */ #define DTRACEBUF_WRAPPED 0x0008 /* ring buffer has wrapped */ #define DTRACEBUF_DROPPED 0x0010 /* drops occurred */ #define DTRACEBUF_ERROR 0x0020 /* errors occurred */ #define DTRACEBUF_FULL 0x0040 /* "fill" buffer is full */ #define DTRACEBUF_CONSUMED 0x0080 /* buffer has been consumed */ #define DTRACEBUF_INACTIVE 0x0100 /* buffer is not yet active */ typedef struct dtrace_buffer { uint64_t dtb_offset; /* current offset in buffer */ uint64_t dtb_size; /* size of buffer */ uint32_t dtb_flags; /* flags */ uint32_t dtb_drops; /* number of drops */ caddr_t dtb_tomax; /* active buffer */ caddr_t dtb_xamot; /* inactive buffer */ uint32_t dtb_xamot_flags; /* inactive flags */ uint32_t dtb_xamot_drops; /* drops in inactive buffer */ uint64_t dtb_xamot_offset; /* offset in inactive buffer */ uint32_t dtb_errors; /* number of errors */ uint32_t dtb_xamot_errors; /* errors in inactive buffer */ #ifndef _LP64 uint64_t dtb_pad1; #endif } dtrace_buffer_t; /* * DTrace Aggregation Buffers * * Aggregation buffers use much of the same mechanism as described above * ("DTrace Buffers"). However, because an aggregation is fundamentally a * hash, there exists dynamic metadata associated with an aggregation buffer * that is not associated with other kinds of buffers. This aggregation * metadata is _only_ relevant for the in-kernel implementation of * aggregations; it is not actually relevant to user-level consumers. To do * this, we allocate dynamic aggregation data (hash keys and hash buckets) * starting below the _limit_ of the buffer, and we allocate data from the * _base_ of the buffer. When the aggregation buffer is copied out, _only_ the * data is copied out; the metadata is simply discarded. Schematically, * aggregation buffers look like: * * base of data buffer ---> +-------+------+-----------+-------+ * | aggid | key | value | aggid | * +-------+------+-----------+-------+ * | key | * +-------+-------+-----+------------+ * | value | aggid | key | value | * +-------+------++-----+------+-----+ * | aggid | key | value | | * +-------+------+-------------+ | * | || | * | || | * | \/ | * : : * . . * . . * . . * : : * | /\ | * | || +------------+ * | || | | * +---------------------+ | * | hash keys | * | (dtrace_aggkey structures) | * | | * +----------------------------------+ * | hash buckets | * | (dtrace_aggbuffer structure) | * | | * limit of data buffer ---> +----------------------------------+ * * * As implied above, just as we assure that ECBs always store a constant * amount of data, we assure that a given aggregation -- identified by its * aggregation ID -- always stores data of a constant quantity and type. * As with EPIDs, this allows the aggregation ID to serve as the metadata for a * given record. * * Note that the size of the dtrace_aggkey structure must be sizeof (uintptr_t) * aligned. (If this the structure changes such that this becomes false, an * assertion will fail in dtrace_aggregate().) */ typedef struct dtrace_aggkey { uint32_t dtak_hashval; /* hash value */ uint32_t dtak_action:4; /* action -- 4 bits */ uint32_t dtak_size:28; /* size -- 28 bits */ caddr_t dtak_data; /* data pointer */ struct dtrace_aggkey *dtak_next; /* next in hash chain */ } dtrace_aggkey_t; typedef struct dtrace_aggbuffer { uintptr_t dtagb_hashsize; /* number of buckets */ uintptr_t dtagb_free; /* free list of keys */ dtrace_aggkey_t **dtagb_hash; /* hash table */ } dtrace_aggbuffer_t; /* * DTrace Speculations * * Speculations have a per-CPU buffer and a global state. Once a speculation * buffer has been comitted or discarded, it cannot be reused until all CPUs * have taken the same action (commit or discard) on their respective * speculative buffer. However, because DTrace probes may execute in arbitrary * context, other CPUs cannot simply be cross-called at probe firing time to * perform the necessary commit or discard. The speculation states thus * optimize for the case that a speculative buffer is only active on one CPU at * the time of a commit() or discard() -- for if this is the case, other CPUs * need not take action, and the speculation is immediately available for * reuse. If the speculation is active on multiple CPUs, it must be * asynchronously cleaned -- potentially leading to a higher rate of dirty * speculative drops. The speculation states are as follows: * * DTRACESPEC_INACTIVE <= Initial state; inactive speculation * DTRACESPEC_ACTIVE <= Allocated, but not yet speculatively traced to * DTRACESPEC_ACTIVEONE <= Speculatively traced to on one CPU * DTRACESPEC_ACTIVEMANY <= Speculatively traced to on more than one CPU * DTRACESPEC_COMMITTING <= Currently being commited on one CPU * DTRACESPEC_COMMITTINGMANY <= Currently being commited on many CPUs * DTRACESPEC_DISCARDING <= Currently being discarded on many CPUs * * The state transition diagram is as follows: * * +----------------------------------------------------------+ * | | * | +------------+ | * | +-------------------| COMMITTING |<-----------------+ | * | | +------------+ | | * | | copied spec. ^ commit() on | | discard() on * | | into principal | active CPU | | active CPU * | | | commit() | | * V V | | | * +----------+ +--------+ +-----------+ * | INACTIVE |---------------->| ACTIVE |--------------->| ACTIVEONE | * +----------+ speculation() +--------+ speculate() +-----------+ * ^ ^ | | | * | | | discard() | | * | | asynchronously | discard() on | | speculate() * | | cleaned V inactive CPU | | on inactive * | | +------------+ | | CPU * | +-------------------| DISCARDING |<-----------------+ | * | +------------+ | * | asynchronously ^ | * | copied spec. | discard() | * | into principal +------------------------+ | * | | V * +----------------+ commit() +------------+ * | COMMITTINGMANY |<----------------------------------| ACTIVEMANY | * +----------------+ +------------+ */ typedef enum dtrace_speculation_state { DTRACESPEC_INACTIVE = 0, DTRACESPEC_ACTIVE, DTRACESPEC_ACTIVEONE, DTRACESPEC_ACTIVEMANY, DTRACESPEC_COMMITTING, DTRACESPEC_COMMITTINGMANY, DTRACESPEC_DISCARDING } dtrace_speculation_state_t; typedef struct dtrace_speculation { dtrace_speculation_state_t dtsp_state; /* current speculation state */ int dtsp_cleaning; /* non-zero if being cleaned */ dtrace_buffer_t *dtsp_buffer; /* speculative buffer */ } dtrace_speculation_t; /* * DTrace Dynamic Variables * * The dynamic variable problem is obviously decomposed into two subproblems: * allocating new dynamic storage, and freeing old dynamic storage. The * presence of the second problem makes the first much more complicated -- or * rather, the absence of the second renders the first trivial. This is the * case with aggregations, for which there is effectively no deallocation of * dynamic storage. (Or more accurately, all dynamic storage is deallocated * when a snapshot is taken of the aggregation.) As DTrace dynamic variables * allow for both dynamic allocation and dynamic deallocation, the * implementation of dynamic variables is quite a bit more complicated than * that of their aggregation kin. * * We observe that allocating new dynamic storage is tricky only because the * size can vary -- the allocation problem is much easier if allocation sizes * are uniform. We further observe that in D, the size of dynamic variables is * actually _not_ dynamic -- dynamic variable sizes may be determined by static * analysis of DIF text. (This is true even of putatively dynamically-sized * objects like strings and stacks, the sizes of which are dictated by the * "stringsize" and "stackframes" variables, respectively.) We exploit this by * performing this analysis on all DIF before enabling any probes. For each * dynamic load or store, we calculate the dynamically-allocated size plus the * size of the dtrace_dynvar structure plus the storage required to key the * data. For all DIF, we take the largest value and dub it the _chunksize_. * We then divide dynamic memory into two parts: a hash table that is wide * enough to have every chunk in its own bucket, and a larger region of equal * chunksize units. Whenever we wish to dynamically allocate a variable, we * always allocate a single chunk of memory. Depending on the uniformity of * allocation, this will waste some amount of memory -- but it eliminates the * non-determinism inherent in traditional heap fragmentation. * * Dynamic objects are allocated by storing a non-zero value to them; they are * deallocated by storing a zero value to them. Dynamic variables are * complicated enormously by being shared between CPUs. In particular, * consider the following scenario: * * CPU A CPU B * +---------------------------------+ +---------------------------------+ * | | | | * | allocates dynamic object a[123] | | | * | by storing the value 345 to it | | | * | ---------> | * | | | wishing to load from object | * | | | a[123], performs lookup in | * | | | dynamic variable space | * | <--------- | * | deallocates object a[123] by | | | * | storing 0 to it | | | * | | | | * | allocates dynamic object b[567] | | performs load from a[123] | * | by storing the value 789 to it | | | * : : : : * . . . . * * This is obviously a race in the D program, but there are nonetheless only * two valid values for CPU B's load from a[123]: 345 or 0. Most importantly, * CPU B may _not_ see the value 789 for a[123]. * * There are essentially two ways to deal with this: * * (1) Explicitly spin-lock variables. That is, if CPU B wishes to load * from a[123], it needs to lock a[123] and hold the lock for the * duration that it wishes to manipulate it. * * (2) Avoid reusing freed chunks until it is known that no CPU is referring * to them. * * The implementation of (1) is rife with complexity, because it requires the * user of a dynamic variable to explicitly decree when they are done using it. * Were all variables by value, this perhaps wouldn't be debilitating -- but * dynamic variables of non-scalar types are tracked by reference. That is, if * a dynamic variable is, say, a string, and that variable is to be traced to, * say, the principal buffer, the DIF emulation code returns to the main * dtrace_probe() loop a pointer to the underlying storage, not the contents of * the storage. Further, code calling on DIF emulation would have to be aware * that the DIF emulation has returned a reference to a dynamic variable that * has been potentially locked. The variable would have to be unlocked after * the main dtrace_probe() loop is finished with the variable, and the main * dtrace_probe() loop would have to be careful to not call any further DIF * emulation while the variable is locked to avoid deadlock. More generally, * if one were to implement (1), DIF emulation code dealing with dynamic * variables could only deal with one dynamic variable at a time (lest deadlock * result). To sum, (1) exports too much subtlety to the users of dynamic * variables -- increasing maintenance burden and imposing serious constraints * on future DTrace development. * * The implementation of (2) is also complex, but the complexity is more * manageable. We need to be sure that when a variable is deallocated, it is * not placed on a traditional free list, but rather on a _dirty_ list. Once a * variable is on a dirty list, it cannot be found by CPUs performing a * subsequent lookup of the variable -- but it may still be in use by other * CPUs. To assure that all CPUs that may be seeing the old variable have * cleared out of probe context, a dtrace_sync() can be issued. Once the * dtrace_sync() has completed, it can be known that all CPUs are done * manipulating the dynamic variable -- the dirty list can be atomically * appended to the free list. Unfortunately, there's a slight hiccup in this * mechanism: dtrace_sync() may not be issued from probe context. The * dtrace_sync() must be therefore issued asynchronously from non-probe * context. For this we rely on the DTrace cleaner, a cyclic that runs at the * "cleanrate" frequency. To ease this implementation, we define several chunk * lists: * * - Dirty. Deallocated chunks, not yet cleaned. Not available. * * - Rinsing. Formerly dirty chunks that are currently being asynchronously * cleaned. Not available, but will be shortly. Dynamic variable * allocation may not spin or block for availability, however. * * - Clean. Clean chunks, ready for allocation -- but not on the free list. * * - Free. Available for allocation. * * Moreover, to avoid absurd contention, _each_ of these lists is implemented * on a per-CPU basis. This is only for performance, not correctness; chunks * may be allocated from another CPU's free list. The algorithm for allocation * then is this: * * (1) Attempt to atomically allocate from current CPU's free list. If list * is non-empty and allocation is successful, allocation is complete. * * (2) If the clean list is non-empty, atomically move it to the free list, * and reattempt (1). * * (3) If the dynamic variable space is in the CLEAN state, look for free * and clean lists on other CPUs by setting the current CPU to the next * CPU, and reattempting (1). If the next CPU is the current CPU (that * is, if all CPUs have been checked), atomically switch the state of * the dynamic variable space based on the following: * * - If no free chunks were found and no dirty chunks were found, * atomically set the state to EMPTY. * * - If dirty chunks were found, atomically set the state to DIRTY. * * - If rinsing chunks were found, atomically set the state to RINSING. * * (4) Based on state of dynamic variable space state, increment appropriate * counter to indicate dynamic drops (if in EMPTY state) vs. dynamic * dirty drops (if in DIRTY state) vs. dynamic rinsing drops (if in * RINSING state). Fail the allocation. * * The cleaning cyclic operates with the following algorithm: for all CPUs * with a non-empty dirty list, atomically move the dirty list to the rinsing * list. Perform a dtrace_sync(). For all CPUs with a non-empty rinsing list, * atomically move the rinsing list to the clean list. Perform another * dtrace_sync(). By this point, all CPUs have seen the new clean list; the * state of the dynamic variable space can be restored to CLEAN. * * There exist two final races that merit explanation. The first is a simple * allocation race: * * CPU A CPU B * +---------------------------------+ +---------------------------------+ * | | | | * | allocates dynamic object a[123] | | allocates dynamic object a[123] | * | by storing the value 345 to it | | by storing the value 567 to it | * | | | | * : : : : * . . . . * * Again, this is a race in the D program. It can be resolved by having a[123] * hold the value 345 or a[123] hold the value 567 -- but it must be true that * a[123] have only _one_ of these values. (That is, the racing CPUs may not * put the same element twice on the same hash chain.) This is resolved * simply: before the allocation is undertaken, the start of the new chunk's * hash chain is noted. Later, after the allocation is complete, the hash * chain is atomically switched to point to the new element. If this fails * (because of either concurrent allocations or an allocation concurrent with a * deletion), the newly allocated chunk is deallocated to the dirty list, and * the whole process of looking up (and potentially allocating) the dynamic * variable is reattempted. * * The final race is a simple deallocation race: * * CPU A CPU B * +---------------------------------+ +---------------------------------+ * | | | | * | deallocates dynamic object | | deallocates dynamic object | * | a[123] by storing the value 0 | | a[123] by storing the value 0 | * | to it | | to it | * | | | | * : : : : * . . . . * * Once again, this is a race in the D program, but it is one that we must * handle without corrupting the underlying data structures. Because * deallocations require the deletion of a chunk from the middle of a hash * chain, we cannot use a single-word atomic operation to remove it. For this, * we add a spin lock to the hash buckets that is _only_ used for deallocations * (allocation races are handled as above). Further, this spin lock is _only_ * held for the duration of the delete; before control is returned to the DIF * emulation code, the hash bucket is unlocked. */ typedef struct dtrace_key { uint64_t dttk_value; /* data value or data pointer */ uint64_t dttk_size; /* 0 if by-val, >0 if by-ref */ } dtrace_key_t; typedef struct dtrace_tuple { uint32_t dtt_nkeys; /* number of keys in tuple */ uint32_t dtt_pad; /* padding */ dtrace_key_t dtt_key[1]; /* array of tuple keys */ } dtrace_tuple_t; typedef struct dtrace_dynvar { uint64_t dtdv_hashval; /* hash value -- 0 if free */ struct dtrace_dynvar *dtdv_next; /* next on list or hash chain */ void *dtdv_data; /* pointer to data */ dtrace_tuple_t dtdv_tuple; /* tuple key */ } dtrace_dynvar_t; typedef enum dtrace_dynvar_op { DTRACE_DYNVAR_ALLOC, DTRACE_DYNVAR_NOALLOC, DTRACE_DYNVAR_DEALLOC } dtrace_dynvar_op_t; typedef struct dtrace_dynhash { dtrace_dynvar_t *dtdh_chain; /* hash chain for this bucket */ uintptr_t dtdh_lock; /* deallocation lock */ #ifdef _LP64 uintptr_t dtdh_pad[6]; /* pad to avoid false sharing */ #else uintptr_t dtdh_pad[14]; /* pad to avoid false sharing */ #endif } dtrace_dynhash_t; typedef struct dtrace_dstate_percpu { dtrace_dynvar_t *dtdsc_free; /* free list for this CPU */ dtrace_dynvar_t *dtdsc_dirty; /* dirty list for this CPU */ dtrace_dynvar_t *dtdsc_rinsing; /* rinsing list for this CPU */ dtrace_dynvar_t *dtdsc_clean; /* clean list for this CPU */ uint64_t dtdsc_drops; /* number of capacity drops */ uint64_t dtdsc_dirty_drops; /* number of dirty drops */ uint64_t dtdsc_rinsing_drops; /* number of rinsing drops */ #ifdef _LP64 uint64_t dtdsc_pad; /* pad to avoid false sharing */ #else uint64_t dtdsc_pad[2]; /* pad to avoid false sharing */ #endif } dtrace_dstate_percpu_t; typedef enum dtrace_dstate_state { DTRACE_DSTATE_CLEAN = 0, DTRACE_DSTATE_EMPTY, DTRACE_DSTATE_DIRTY, DTRACE_DSTATE_RINSING } dtrace_dstate_state_t; typedef struct dtrace_dstate { void *dtds_base; /* base of dynamic var. space */ size_t dtds_size; /* size of dynamic var. space */ size_t dtds_hashsize; /* number of buckets in hash */ size_t dtds_chunksize; /* size of each chunk */ dtrace_dynhash_t *dtds_hash; /* pointer to hash table */ dtrace_dstate_state_t dtds_state; /* current dynamic var. state */ dtrace_dstate_percpu_t *dtds_percpu; /* per-CPU dyn. var. state */ } dtrace_dstate_t; /* * DTrace Variable State * * The DTrace variable state tracks user-defined variables in its dtrace_vstate * structure. Each DTrace consumer has exactly one dtrace_vstate structure, * but some dtrace_vstate structures may exist without a corresponding DTrace * consumer (see "DTrace Helpers", below). As described in <sys/dtrace.h>, * user-defined variables can have one of three scopes: * * DIFV_SCOPE_GLOBAL => global scope * DIFV_SCOPE_THREAD => thread-local scope (i.e. "self->" variables) * DIFV_SCOPE_LOCAL => clause-local scope (i.e. "this->" variables) * * The variable state tracks variables by both their scope and their allocation * type: * * - The dtvs_globals and dtvs_locals members each point to an array of * dtrace_statvar structures. These structures contain both the variable * metadata (dtrace_difv structures) and the underlying storage for all * statically allocated variables, including statically allocated * DIFV_SCOPE_GLOBAL variables and all DIFV_SCOPE_LOCAL variables. * * - The dtvs_tlocals member points to an array of dtrace_difv structures for * DIFV_SCOPE_THREAD variables. As such, this array tracks _only_ the * variable metadata for DIFV_SCOPE_THREAD variables; the underlying storage * is allocated out of the dynamic variable space. * * - The dtvs_dynvars member is the dynamic variable state associated with the * variable state. The dynamic variable state (described in "DTrace Dynamic * Variables", above) tracks all DIFV_SCOPE_THREAD variables and all * dynamically-allocated DIFV_SCOPE_GLOBAL variables. */ typedef struct dtrace_statvar { uint64_t dtsv_data; /* data or pointer to it */ size_t dtsv_size; /* size of pointed-to data */ int dtsv_refcnt; /* reference count */ dtrace_difv_t dtsv_var; /* variable metadata */ } dtrace_statvar_t; typedef struct dtrace_vstate { dtrace_state_t *dtvs_state; /* back pointer to state */ dtrace_statvar_t **dtvs_globals; /* statically-allocated glbls */ int dtvs_nglobals; /* number of globals */ dtrace_difv_t *dtvs_tlocals; /* thread-local metadata */ int dtvs_ntlocals; /* number of thread-locals */ dtrace_statvar_t **dtvs_locals; /* clause-local data */ int dtvs_nlocals; /* number of clause-locals */ dtrace_dstate_t dtvs_dynvars; /* dynamic variable state */ } dtrace_vstate_t; /* * DTrace Machine State * * In the process of processing a fired probe, DTrace needs to track and/or * cache some per-CPU state associated with that particular firing. This is * state that is always discarded after the probe firing has completed, and * much of it is not specific to any DTrace consumer, remaining valid across * all ECBs. This state is tracked in the dtrace_mstate structure. */ #define DTRACE_MSTATE_ARGS 0x00000001 #define DTRACE_MSTATE_PROBE 0x00000002 #define DTRACE_MSTATE_EPID 0x00000004 #define DTRACE_MSTATE_TIMESTAMP 0x00000008 #define DTRACE_MSTATE_STACKDEPTH 0x00000010 #define DTRACE_MSTATE_CALLER 0x00000020 #define DTRACE_MSTATE_IPL 0x00000040 #define DTRACE_MSTATE_FLTOFFS 0x00000080 #define DTRACE_MSTATE_WALLTIMESTAMP 0x00000100 #define DTRACE_MSTATE_USTACKDEPTH 0x00000200 #define DTRACE_MSTATE_UCALLER 0x00000400 typedef struct dtrace_mstate { uintptr_t dtms_scratch_base; /* base of scratch space */ uintptr_t dtms_scratch_ptr; /* current scratch pointer */ size_t dtms_scratch_size; /* scratch size */ uint32_t dtms_present; /* variables that are present */ uint64_t dtms_arg[5]; /* cached arguments */ dtrace_epid_t dtms_epid; /* current EPID */ uint64_t dtms_timestamp; /* cached timestamp */ hrtime_t dtms_walltimestamp; /* cached wall timestamp */ int dtms_stackdepth; /* cached stackdepth */ int dtms_ustackdepth; /* cached ustackdepth */ struct dtrace_probe *dtms_probe; /* current probe */ uintptr_t dtms_caller; /* cached caller */ uint64_t dtms_ucaller; /* cached user-level caller */ int dtms_ipl; /* cached interrupt pri lev */ int dtms_fltoffs; /* faulting DIFO offset */ uintptr_t dtms_strtok; /* saved strtok() pointer */ } dtrace_mstate_t; #define DTRACE_COND_OWNER 0x1 #define DTRACE_COND_USERMODE 0x2 #define DTRACE_COND_ZONEOWNER 0x4 #define DTRACE_PROBEKEY_MAXDEPTH 8 /* max glob recursion depth */ /* * DTrace Activity * * Each DTrace consumer is in one of several states, which (for purposes of * avoiding yet-another overloading of the noun "state") we call the current * _activity_. The activity transitions on dtrace_go() (from DTRACIOCGO), on * dtrace_stop() (from DTRACIOCSTOP) and on the exit() action. Activities may * only transition in one direction; the activity transition diagram is a * directed acyclic graph. The activity transition diagram is as follows: * * * +----------+ +--------+ +--------+ * | INACTIVE |------------------>| WARMUP |------------------>| ACTIVE | * +----------+ dtrace_go(), +--------+ dtrace_go(), +--------+ * before BEGIN | after BEGIN | | | * | | | | * exit() action | | | | * from BEGIN ECB | | | | * | | | | * v | | | * +----------+ exit() action | | | * +-----------------------------| DRAINING |<-------------------+ | | * | +----------+ | | * | | | | * | dtrace_stop(), | | | * | before END | | | * | | | | * | v | | * | +---------+ +----------+ | | * | | STOPPED |<----------------| COOLDOWN |<----------------------+ | * | +---------+ dtrace_stop(), +----------+ dtrace_stop(), | * | after END before END | * | | * | +--------+ | * +----------------------------->| KILLED |<--------------------------+ * deadman timeout or +--------+ deadman timeout or * killed consumer killed consumer * * Note that once a DTrace consumer has stopped tracing, there is no way to * restart it; if a DTrace consumer wishes to restart tracing, it must reopen * the DTrace pseudodevice. */ typedef enum dtrace_activity { DTRACE_ACTIVITY_INACTIVE = 0, /* not yet running */ DTRACE_ACTIVITY_WARMUP, /* while starting */ DTRACE_ACTIVITY_ACTIVE, /* running */ DTRACE_ACTIVITY_DRAINING, /* before stopping */ DTRACE_ACTIVITY_COOLDOWN, /* while stopping */ DTRACE_ACTIVITY_STOPPED, /* after stopping */ DTRACE_ACTIVITY_KILLED /* killed */ } dtrace_activity_t; /* * DTrace dof modes * * DTrace has four "dof modes". They are: * * DTRACE_DOF_MODE_NEVER Never load any dof, period. * DTRACE_DOF_MODE_LAZY_ON Defer loading dof until later * DTRACE_DOF_MODE_LAZY_OFF Load all deferred dof now, and any new dof * DTRACE_DOF_MODE_NON_LAZY Load all dof immediately. * * It is legal to transition between the two lazy modes. The NEVER and * NON_LAZY modes are permanent, and must not change once set. * * The current dof mode is kept in dtrace_dof_mode, which is protected by the * dtrace_dof_mode_lock. This is a RW lock, reads require shared access, writes * require exclusive access. Because NEVER and NON_LAZY are permanent states, * it is legal to test for those modes without holding the dof mode lock. * * Lock ordering is dof mode lock before any dtrace lock, and before the * process p_dtrace_sprlock. In general, other locks should not be held when * taking the dof mode lock. Acquiring the dof mode lock in exclusive mode * will block process fork, exec, and exit, so it should be held exclusive * for as short a time as possible. */ #define DTRACE_DOF_MODE_NEVER 0 #define DTRACE_DOF_MODE_LAZY_ON 1 #define DTRACE_DOF_MODE_LAZY_OFF 2 #define DTRACE_DOF_MODE_NON_LAZY 3 /* * DTrace Helper Implementation * * A description of the helper architecture may be found in <sys/dtrace.h>. * Each process contains a pointer to its helpers in its p_dtrace_helpers * member. This is a pointer to a dtrace_helpers structure, which contains an * array of pointers to dtrace_helper structures, helper variable state (shared * among a process's helpers) and a generation count. (The generation count is * used to provide an identifier when a helper is added so that it may be * subsequently removed.) The dtrace_helper structure is self-explanatory, * containing pointers to the objects needed to execute the helper. Note that * helpers are _duplicated_ across fork(2), and destroyed on exec(2). No more * than dtrace_helpers_max are allowed per-process. */ #define DTRACE_HELPER_ACTION_USTACK 0 #define DTRACE_NHELPER_ACTIONS 1 typedef struct dtrace_helper_action { int dtha_generation; /* helper action generation */ int dtha_nactions; /* number of actions */ dtrace_difo_t *dtha_predicate; /* helper action predicate */ dtrace_difo_t **dtha_actions; /* array of actions */ struct dtrace_helper_action *dtha_next; /* next helper action */ } dtrace_helper_action_t; typedef struct dtrace_helper_provider { int dthp_generation; /* helper provider generation */ uint32_t dthp_ref; /* reference count */ dof_helper_t dthp_prov; /* DOF w/ provider and probes */ } dtrace_helper_provider_t; typedef struct dtrace_helpers { dtrace_helper_action_t **dthps_actions; /* array of helper actions */ dtrace_vstate_t dthps_vstate; /* helper action var. state */ dtrace_helper_provider_t **dthps_provs; /* array of providers */ uint_t dthps_nprovs; /* count of providers */ uint_t dthps_maxprovs; /* provider array size */ int dthps_generation; /* current generation */ pid_t dthps_pid; /* pid of associated proc */ int dthps_deferred; /* helper in deferred list */ struct dtrace_helpers *dthps_next; /* next pointer */ struct dtrace_helpers *dthps_prev; /* prev pointer */ } dtrace_helpers_t; /* * DTrace Helper Action Tracing * * Debugging helper actions can be arduous. To ease the development and * debugging of helpers, DTrace contains a tracing-framework-within-a-tracing- * framework: helper tracing. If dtrace_helptrace_enabled is non-zero (which * it is by default on DEBUG kernels), all helper activity will be traced to a * global, in-kernel ring buffer. Each entry includes a pointer to the specific * helper, the location within the helper, and a trace of all local variables. * The ring buffer may be displayed in a human-readable format with the * ::dtrace_helptrace mdb(1) dcmd. */ #define DTRACE_HELPTRACE_NEXT (-1) #define DTRACE_HELPTRACE_DONE (-2) #define DTRACE_HELPTRACE_ERR (-3) typedef struct dtrace_helptrace { dtrace_helper_action_t *dtht_helper; /* helper action */ int dtht_where; /* where in helper action */ int dtht_nlocals; /* number of locals */ int dtht_fault; /* type of fault (if any) */ int dtht_fltoffs; /* DIF offset */ uint64_t dtht_illval; /* faulting value */ uint64_t dtht_locals[1]; /* local variables */ } dtrace_helptrace_t; /* * DTrace Credentials * * In probe context, we have limited flexibility to examine the credentials * of the DTrace consumer that created a particular enabling. We use * the Least Privilege interfaces to cache the consumer's cred pointer and * some facts about that credential in a dtrace_cred_t structure. These * can limit the consumer's breadth of visibility and what actions the * consumer may take. */ #define DTRACE_CRV_ALLPROC 0x01 #define DTRACE_CRV_KERNEL 0x02 #define DTRACE_CRV_ALLZONE 0x04 #define DTRACE_CRV_ALL (DTRACE_CRV_ALLPROC | DTRACE_CRV_KERNEL | \ DTRACE_CRV_ALLZONE) #define DTRACE_CRA_PROC 0x0001 #define DTRACE_CRA_PROC_CONTROL 0x0002 #define DTRACE_CRA_PROC_DESTRUCTIVE_ALLUSER 0x0004 #define DTRACE_CRA_PROC_DESTRUCTIVE_ALLZONE 0x0008 #define DTRACE_CRA_PROC_DESTRUCTIVE_CREDCHG 0x0010 #define DTRACE_CRA_KERNEL 0x0020 #define DTRACE_CRA_KERNEL_DESTRUCTIVE 0x0040 #define DTRACE_CRA_ALL (DTRACE_CRA_PROC | \ DTRACE_CRA_PROC_CONTROL | \ DTRACE_CRA_PROC_DESTRUCTIVE_ALLUSER | \ DTRACE_CRA_PROC_DESTRUCTIVE_ALLZONE | \ DTRACE_CRA_PROC_DESTRUCTIVE_CREDCHG | \ DTRACE_CRA_KERNEL | \ DTRACE_CRA_KERNEL_DESTRUCTIVE) typedef struct dtrace_cred { cred_t *dcr_cred; uint8_t dcr_destructive; uint8_t dcr_visible; uint16_t dcr_action; } dtrace_cred_t; /* * DTrace Consumer State * * Each DTrace consumer has an associated dtrace_state structure that contains * its in-kernel DTrace state -- including options, credentials, statistics and * pointers to ECBs, buffers, speculations and formats. A dtrace_state * structure is also allocated for anonymous enablings. When anonymous state * is grabbed, the grabbing consumers dts_anon pointer is set to the grabbed * dtrace_state structure. */ struct dtrace_state { dev_t dts_dev; /* device */ int dts_necbs; /* total number of ECBs */ dtrace_ecb_t **dts_ecbs; /* array of ECBs */ dtrace_epid_t dts_epid; /* next EPID to allocate */ size_t dts_needed; /* greatest needed space */ struct dtrace_state *dts_anon; /* anon. state, if grabbed */ dtrace_activity_t dts_activity; /* current activity */ dtrace_vstate_t dts_vstate; /* variable state */ dtrace_buffer_t *dts_buffer; /* principal buffer */ dtrace_buffer_t *dts_aggbuffer; /* aggregation buffer */ dtrace_speculation_t *dts_speculations; /* speculation array */ int dts_nspeculations; /* number of speculations */ int dts_naggregations; /* number of aggregations */ dtrace_aggregation_t **dts_aggregations; /* aggregation array */ vmem_t *dts_aggid_arena; /* arena for aggregation IDs */ uint64_t dts_errors; /* total number of errors */ uint32_t dts_speculations_busy; /* number of spec. busy */ uint32_t dts_speculations_unavail; /* number of spec unavail */ uint32_t dts_stkstroverflows; /* stack string tab overflows */ uint32_t dts_dblerrors; /* errors in ERROR probes */ uint32_t dts_reserve; /* space reserved for END */ hrtime_t dts_laststatus; /* time of last status */ cyclic_id_t dts_cleaner; /* cleaning cyclic */ cyclic_id_t dts_deadman; /* deadman cyclic */ hrtime_t dts_alive; /* time last alive */ char dts_speculates; /* boolean: has speculations */ char dts_destructive; /* boolean: has dest. actions */ int dts_nformats; /* number of formats */ char **dts_formats; /* format string array */ dtrace_optval_t dts_options[DTRACEOPT_MAX]; /* options */ dtrace_cred_t dts_cred; /* credentials */ size_t dts_nretained; /* number of retained enabs */ #if defined(__APPLE__) uint64_t dts_arg_error_illval; #endif /* __APPLE__ */ }; struct dtrace_provider { dtrace_pattr_t dtpv_attr; /* provider attributes */ dtrace_ppriv_t dtpv_priv; /* provider privileges */ dtrace_pops_t dtpv_pops; /* provider operations */ char *dtpv_name; /* provider name */ void *dtpv_arg; /* provider argument */ uint_t dtpv_defunct; /* boolean: defunct provider */ struct dtrace_provider *dtpv_next; /* next provider */ }; struct dtrace_meta { dtrace_mops_t dtm_mops; /* meta provider operations */ char *dtm_name; /* meta provider name */ void *dtm_arg; /* meta provider user arg */ uint64_t dtm_count; /* no. of associated provs. */ }; /* * DTrace Enablings * * A dtrace_enabling structure is used to track a collection of ECB * descriptions -- before they have been turned into actual ECBs. This is * created as a result of DOF processing, and is generally used to generate * ECBs immediately thereafter. However, enablings are also generally * retained should the probes they describe be created at a later time; as * each new module or provider registers with the framework, the retained * enablings are reevaluated, with any new match resulting in new ECBs. To * prevent probes from being matched more than once, the enabling tracks the * last probe generation matched, and only matches probes from subsequent * generations. */ typedef struct dtrace_enabling { dtrace_ecbdesc_t **dten_desc; /* all ECB descriptions */ int dten_ndesc; /* number of ECB descriptions */ int dten_maxdesc; /* size of ECB array */ dtrace_vstate_t *dten_vstate; /* associated variable state */ dtrace_genid_t dten_probegen; /* matched probe generation */ dtrace_ecbdesc_t *dten_current; /* current ECB description */ int dten_error; /* current error value */ int dten_primed; /* boolean: set if primed */ struct dtrace_enabling *dten_prev; /* previous enabling */ struct dtrace_enabling *dten_next; /* next enabling */ } dtrace_enabling_t; /* * DTrace Anonymous Enablings * * Anonymous enablings are DTrace enablings that are not associated with a * controlling process, but rather derive their enabling from DOF stored as * properties in the dtrace.conf file. If there is an anonymous enabling, a * DTrace consumer state and enabling are created on attach. The state may be * subsequently grabbed by the first consumer specifying the "grabanon" * option. As long as an anonymous DTrace enabling exists, dtrace(7D) will * refuse to unload. */ typedef struct dtrace_anon { dtrace_state_t *dta_state; /* DTrace consumer state */ dtrace_enabling_t *dta_enabling; /* pointer to enabling */ processorid_t dta_beganon; /* which CPU BEGIN ran on */ } dtrace_anon_t; /* * DTrace Error Debugging */ #ifdef DEBUG #define DTRACE_ERRDEBUG #endif #ifdef DTRACE_ERRDEBUG typedef struct dtrace_errhash { const char *dter_msg; /* error message */ int dter_count; /* number of times seen */ } dtrace_errhash_t; #define DTRACE_ERRHASHSZ 256 /* must be > number of err msgs */ #endif /* DTRACE_ERRDEBUG */ /* * DTrace Toxic Ranges * * DTrace supports safe loads from probe context; if the address turns out to * be invalid, a bit will be set by the kernel indicating that DTrace * encountered a memory error, and DTrace will propagate the error to the user * accordingly. However, there may exist some regions of memory in which an * arbitrary load can change system state, and from which it is impossible to * recover from such a load after it has been attempted. Examples of this may * include memory in which programmable I/O registers are mapped (for which a * read may have some implications for the device) or (in the specific case of * UltraSPARC-I and -II) the virtual address hole. The platform is required * to make DTrace aware of these toxic ranges; DTrace will then check that * target addresses are not in a toxic range before attempting to issue a * safe load. */ typedef struct dtrace_toxrange { uintptr_t dtt_base; /* base of toxic range */ uintptr_t dtt_limit; /* limit of toxic range */ } dtrace_toxrange_t; extern uint64_t dtrace_getarg(int, int); extern greg_t dtrace_getfp(void); extern int dtrace_getipl(void); extern uintptr_t dtrace_caller(int); extern uint32_t dtrace_cas32(uint32_t *, uint32_t, uint32_t); extern void *dtrace_casptr(void *, void *, void *); #if !defined(__APPLE__) extern void dtrace_copyin(uintptr_t, uintptr_t, size_t); extern void dtrace_copyinstr(uintptr_t, uintptr_t, size_t); extern void dtrace_copyout(uintptr_t, uintptr_t, size_t); extern void dtrace_copyoutstr(uintptr_t, uintptr_t, size_t); #else extern void dtrace_copyin(user_addr_t, uintptr_t, size_t); extern void dtrace_copyinstr(user_addr_t, uintptr_t, size_t); extern void dtrace_copyout(uintptr_t, user_addr_t, size_t); extern void dtrace_copyoutstr(uintptr_t, user_addr_t, size_t); #endif /* __APPLE__ */ extern void dtrace_getpcstack(pc_t *, int, int, uint32_t *); #if !defined(__APPLE__) extern ulong_t dtrace_getreg(struct regs *, uint_t); #else extern uint64_t dtrace_getreg(struct regs *, uint_t); #endif /* __APPLE__ */ extern int dtrace_getstackdepth(int); extern void dtrace_getupcstack(uint64_t *, int); extern void dtrace_getufpstack(uint64_t *, uint64_t *, int); extern int dtrace_getustackdepth(void); extern uintptr_t dtrace_fulword(void *); #if !defined(__APPLE__) extern uint8_t dtrace_fuword8(void *); extern uint16_t dtrace_fuword16(void *); extern uint32_t dtrace_fuword32(void *); extern uint64_t dtrace_fuword64(void *); extern void dtrace_probe_error(dtrace_state_t *, dtrace_epid_t, int, int, int, uintptr_t); #else extern uint8_t dtrace_fuword8(user_addr_t); extern uint16_t dtrace_fuword16(user_addr_t); extern uint32_t dtrace_fuword32(user_addr_t); extern uint64_t dtrace_fuword64(user_addr_t); extern void dtrace_probe_error(dtrace_state_t *, dtrace_epid_t, int, int, int, uint64_t); #endif /* __APPLE__ */ extern int dtrace_assfail(const char *, const char *, int); extern int dtrace_attached(void); extern hrtime_t dtrace_gethrestime(void); #ifdef __sparc extern void dtrace_flush_windows(void); extern void dtrace_flush_user_windows(void); extern uint_t dtrace_getotherwin(void); extern uint_t dtrace_getfprs(void); #else extern void dtrace_copy(uintptr_t, uintptr_t, size_t); extern void dtrace_copystr(uintptr_t, uintptr_t, size_t); #endif /* * DTrace Assertions * * DTrace calls ASSERT from probe context. To assure that a failed ASSERT * does not induce a markedly more catastrophic failure (e.g., one from which * a dump cannot be gleaned), DTrace must define its own ASSERT to be one that * may safely be called from probe context. This header file must thus be * included by any DTrace component that calls ASSERT from probe context, and * _only_ by those components. (The only exception to this is kernel * debugging infrastructure at user-level that doesn't depend on calling * ASSERT.) */ #undef ASSERT #ifdef DEBUG #define ASSERT(EX) ((void)((EX) || \ dtrace_assfail(#EX, __FILE__, __LINE__))) #else #define ASSERT(X) ((void)0) #endif #ifdef __cplusplus } #endif #endif /* _SYS_DTRACE_IMPL_H */