| 1 | /* |
| 2 | * Copyright (C) 2007-2011 Mathieu Desnoyers |
| 3 | * |
| 4 | * This library is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU Lesser General Public |
| 6 | * License as published by the Free Software Foundation; |
| 7 | * version 2.1 of the License. |
| 8 | * |
| 9 | * This library is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 12 | * Lesser General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU Lesser General Public |
| 15 | * License along with this library; if not, write to the Free Software |
| 16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 17 | */ |
| 18 | |
| 19 | #define _LGPL_SOURCE |
| 20 | #include <stdlib.h> |
| 21 | #include <errno.h> |
| 22 | #include <pthread.h> |
| 23 | #include <urcu-call-rcu.h> |
| 24 | #include <urcu-bp.h> |
| 25 | #include <urcu/rculist.h> |
| 26 | #include <urcu/hlist.h> |
| 27 | |
| 28 | #include <ust/core.h> |
| 29 | #include <ust/marker.h> |
| 30 | #include <ust/marker-internal.h> |
| 31 | #include <ust/tracepoint.h> |
| 32 | #include <ust/tracepoint-internal.h> |
| 33 | |
| 34 | #include "usterr_signal_safe.h" |
| 35 | #include "channels.h" |
| 36 | #include "tracercore.h" |
| 37 | #include "tracer.h" |
| 38 | |
| 39 | extern struct ust_marker * const __start___ust_marker_ptrs[] __attribute__((visibility("hidden"))); |
| 40 | extern struct ust_marker * const __stop___ust_marker_ptrs[] __attribute__((visibility("hidden"))); |
| 41 | |
| 42 | /* Set to 1 to enable ust_marker debug output */ |
| 43 | static const int ust_marker_debug; |
| 44 | static int initialized; |
| 45 | static void (*new_ust_marker_cb)(struct ust_marker *); |
| 46 | |
| 47 | /* |
| 48 | * ust_marker mutex protects the builtin and module ust_marker and the |
| 49 | * hash table, as well as the ust_marker_libs list. |
| 50 | */ |
| 51 | static DEFINE_MUTEX(ust_marker_mutex); |
| 52 | static CDS_LIST_HEAD(ust_marker_libs); |
| 53 | |
| 54 | /* |
| 55 | * Allow nested mutex for mutex listing and nested enable. |
| 56 | */ |
| 57 | static __thread int nested_mutex; |
| 58 | |
| 59 | void lock_ust_marker(void) |
| 60 | { |
| 61 | if (!(nested_mutex++)) |
| 62 | pthread_mutex_lock(&ust_marker_mutex); |
| 63 | } |
| 64 | |
| 65 | void unlock_ust_marker(void) |
| 66 | { |
| 67 | if (!(--nested_mutex)) |
| 68 | pthread_mutex_unlock(&ust_marker_mutex); |
| 69 | } |
| 70 | |
| 71 | /* |
| 72 | * ust_marker hash table, containing the active ust_marker. |
| 73 | * Protected by ust_marker mutex. |
| 74 | */ |
| 75 | #define UST_MARKER_HASH_BITS 6 |
| 76 | #define UST_MARKER_TABLE_SIZE (1 << UST_MARKER_HASH_BITS) |
| 77 | static struct cds_hlist_head ust_marker_table[UST_MARKER_TABLE_SIZE]; |
| 78 | |
| 79 | struct ust_marker_probe_array { |
| 80 | struct rcu_head rcu; |
| 81 | struct ust_marker_probe_closure c[0]; |
| 82 | }; |
| 83 | |
| 84 | /* |
| 85 | * Note about RCU : |
| 86 | * It is used to make sure every handler has finished using its private |
| 87 | * data between two consecutive operation (add or remove) on a given |
| 88 | * ust_marker. It is also used to delay the free of multiple probes |
| 89 | * array until a quiescent state is reached. ust_marker entries |
| 90 | * modifications are protected by the ust_marker_mutex. |
| 91 | */ |
| 92 | struct ust_marker_entry { |
| 93 | struct cds_hlist_node hlist; |
| 94 | char *format; |
| 95 | char *name; |
| 96 | /* Probe wrapper */ |
| 97 | void (*call)(const struct ust_marker *mdata, void *call_private, ...); |
| 98 | struct ust_marker_probe_closure single; |
| 99 | struct ust_marker_probe_array *multi; |
| 100 | int refcount; /* Number of times armed. 0 if disarmed. */ |
| 101 | u16 channel_id; |
| 102 | u16 event_id; |
| 103 | unsigned char ptype:1; |
| 104 | unsigned char format_allocated:1; |
| 105 | char channel[0]; /* Contains channel'\0'name'\0'format'\0' */ |
| 106 | }; |
| 107 | |
| 108 | /** |
| 109 | * __ust_marker_empty_function - Empty probe callback |
| 110 | * @mdata: ust_marker data |
| 111 | * @probe_private: probe private data |
| 112 | * @call_private: call site private data |
| 113 | * @fmt: format string |
| 114 | * @...: variable argument list |
| 115 | * |
| 116 | * Empty callback provided as a probe to the ust_marker. By providing |
| 117 | * this to a disabled ust_marker, we make sure the execution flow is |
| 118 | * always valid even though the function pointer change and the |
| 119 | * ust_marker enabling are two distinct operations that modifies the |
| 120 | * execution flow of preemptible code. |
| 121 | */ |
| 122 | notrace void __ust_marker_empty_function(const struct ust_marker *mdata, |
| 123 | void *probe_private, void *call_private, const char *fmt, va_list *args) |
| 124 | { |
| 125 | } |
| 126 | |
| 127 | /* |
| 128 | * ust_marker_probe_cb Callback that prepares the variable argument list for probes. |
| 129 | * @mdata: pointer of type struct ust_marker |
| 130 | * @call_private: caller site private data |
| 131 | * @...: Variable argument list. |
| 132 | * |
| 133 | * Since we do not use "typical" pointer based RCU in the 1 argument case, we |
| 134 | * need to put a full cmm_smp_rmb() in this branch. This is why we do not use |
| 135 | * rcu_dereference() for the pointer read. |
| 136 | */ |
| 137 | notrace void ust_marker_probe_cb(const struct ust_marker *mdata, |
| 138 | void *call_private, ...) |
| 139 | { |
| 140 | va_list args; |
| 141 | char ptype; |
| 142 | |
| 143 | /* |
| 144 | * rcu_read_lock_sched does two things : disabling preemption to make |
| 145 | * sure the teardown of the callbacks can be done correctly when they |
| 146 | * are in modules and they insure RCU read coherency. |
| 147 | */ |
| 148 | rcu_read_lock(); |
| 149 | ptype = mdata->ptype; |
| 150 | if (likely(!ptype)) { |
| 151 | ust_marker_probe_func *func; |
| 152 | /* Must read the ptype before ptr. They are not data dependant, |
| 153 | * so we put an explicit cmm_smp_rmb() here. */ |
| 154 | cmm_smp_rmb(); |
| 155 | func = mdata->single.func; |
| 156 | /* Must read the ptr before private data. They are not data |
| 157 | * dependant, so we put an explicit cmm_smp_rmb() here. */ |
| 158 | cmm_smp_rmb(); |
| 159 | va_start(args, call_private); |
| 160 | func(mdata, mdata->single.probe_private, call_private, |
| 161 | mdata->format, &args); |
| 162 | va_end(args); |
| 163 | } else { |
| 164 | struct ust_marker_probe_array *multi; |
| 165 | int i; |
| 166 | /* |
| 167 | * Read mdata->ptype before mdata->multi. |
| 168 | */ |
| 169 | cmm_smp_rmb(); |
| 170 | multi = mdata->multi; |
| 171 | /* |
| 172 | * multi points to an array, therefore accessing the array |
| 173 | * depends on reading multi. However, even in this case, |
| 174 | * we must insure that the pointer is read _before_ the array |
| 175 | * data. Same as rcu_dereference, but we need a full cmm_smp_rmb() |
| 176 | * in the fast path, so put the explicit cmm_barrier here. |
| 177 | */ |
| 178 | cmm_smp_read_barrier_depends(); |
| 179 | for (i = 0; multi->c[i].func; i++) { |
| 180 | va_start(args, call_private); |
| 181 | multi->c[i].func(mdata, multi->c[i].probe_private, |
| 182 | call_private, mdata->format, &args); |
| 183 | va_end(args); |
| 184 | } |
| 185 | } |
| 186 | rcu_read_unlock(); |
| 187 | } |
| 188 | |
| 189 | /* |
| 190 | * ust_marker_probe_cb Callback that does not prepare the variable argument list. |
| 191 | * @mdata: pointer of type struct ust_marker |
| 192 | * @call_private: caller site private data |
| 193 | * @...: Variable argument list. |
| 194 | * |
| 195 | * Should be connected to ust_marker "UST_MARKER_NOARGS". |
| 196 | */ |
| 197 | static notrace void ust_marker_probe_cb_noarg(const struct ust_marker *mdata, |
| 198 | void *call_private, ...) |
| 199 | { |
| 200 | va_list args; /* not initialized */ |
| 201 | char ptype; |
| 202 | |
| 203 | rcu_read_lock(); |
| 204 | ptype = mdata->ptype; |
| 205 | if (likely(!ptype)) { |
| 206 | ust_marker_probe_func *func; |
| 207 | /* Must read the ptype before ptr. They are not data dependant, |
| 208 | * so we put an explicit cmm_smp_rmb() here. */ |
| 209 | cmm_smp_rmb(); |
| 210 | func = mdata->single.func; |
| 211 | /* Must read the ptr before private data. They are not data |
| 212 | * dependant, so we put an explicit cmm_smp_rmb() here. */ |
| 213 | cmm_smp_rmb(); |
| 214 | func(mdata, mdata->single.probe_private, call_private, |
| 215 | mdata->format, &args); |
| 216 | } else { |
| 217 | struct ust_marker_probe_array *multi; |
| 218 | int i; |
| 219 | /* |
| 220 | * Read mdata->ptype before mdata->multi. |
| 221 | */ |
| 222 | cmm_smp_rmb(); |
| 223 | multi = mdata->multi; |
| 224 | /* |
| 225 | * multi points to an array, therefore accessing the array |
| 226 | * depends on reading multi. However, even in this case, |
| 227 | * we must insure that the pointer is read _before_ the array |
| 228 | * data. Same as rcu_dereference, but we need a full cmm_smp_rmb() |
| 229 | * in the fast path, so put the explicit cmm_barrier here. |
| 230 | */ |
| 231 | cmm_smp_read_barrier_depends(); |
| 232 | for (i = 0; multi->c[i].func; i++) |
| 233 | multi->c[i].func(mdata, multi->c[i].probe_private, |
| 234 | call_private, mdata->format, &args); |
| 235 | } |
| 236 | rcu_read_unlock(); |
| 237 | } |
| 238 | |
| 239 | static void free_old_closure(struct rcu_head *head) |
| 240 | { |
| 241 | struct ust_marker_probe_array *multi = |
| 242 | _ust_container_of(head, struct ust_marker_probe_array, rcu); |
| 243 | free(multi); |
| 244 | } |
| 245 | |
| 246 | static void debug_print_probes(struct ust_marker_entry *entry) |
| 247 | { |
| 248 | int i; |
| 249 | |
| 250 | if (!ust_marker_debug) |
| 251 | return; |
| 252 | |
| 253 | if (!entry->ptype) { |
| 254 | DBG("Single probe : %p %p", |
| 255 | entry->single.func, |
| 256 | entry->single.probe_private); |
| 257 | } else { |
| 258 | for (i = 0; entry->multi->c[i].func; i++) |
| 259 | DBG("Multi probe %d : %p %p", i, |
| 260 | entry->multi->c[i].func, |
| 261 | entry->multi->c[i].probe_private); |
| 262 | } |
| 263 | } |
| 264 | |
| 265 | static struct ust_marker_probe_array * |
| 266 | ust_marker_entry_add_probe(struct ust_marker_entry *entry, |
| 267 | ust_marker_probe_func *probe, void *probe_private) |
| 268 | { |
| 269 | int nr_probes = 0; |
| 270 | struct ust_marker_probe_array *old, *new; |
| 271 | |
| 272 | WARN_ON(!probe); |
| 273 | |
| 274 | debug_print_probes(entry); |
| 275 | old = entry->multi; |
| 276 | if (!entry->ptype) { |
| 277 | if (entry->single.func == probe && |
| 278 | entry->single.probe_private == probe_private) |
| 279 | return ERR_PTR(-EBUSY); |
| 280 | if (entry->single.func == __ust_marker_empty_function) { |
| 281 | /* 0 -> 1 probes */ |
| 282 | entry->single.func = probe; |
| 283 | entry->single.probe_private = probe_private; |
| 284 | entry->refcount = 1; |
| 285 | entry->ptype = 0; |
| 286 | debug_print_probes(entry); |
| 287 | return NULL; |
| 288 | } else { |
| 289 | /* 1 -> 2 probes */ |
| 290 | nr_probes = 1; |
| 291 | old = NULL; |
| 292 | } |
| 293 | } else { |
| 294 | /* (N -> N+1), (N != 0, 1) probes */ |
| 295 | for (nr_probes = 0; old->c[nr_probes].func; nr_probes++) |
| 296 | if (old->c[nr_probes].func == probe |
| 297 | && old->c[nr_probes].probe_private |
| 298 | == probe_private) |
| 299 | return ERR_PTR(-EBUSY); |
| 300 | } |
| 301 | /* + 2 : one for new probe, one for NULL func */ |
| 302 | new = zmalloc(sizeof(struct ust_marker_probe_array) |
| 303 | + ((nr_probes + 2) * sizeof(struct ust_marker_probe_closure))); |
| 304 | if (new == NULL) |
| 305 | return ERR_PTR(-ENOMEM); |
| 306 | if (!old) |
| 307 | new->c[0] = entry->single; |
| 308 | else |
| 309 | memcpy(&new->c[0], &old->c[0], |
| 310 | nr_probes * sizeof(struct ust_marker_probe_closure)); |
| 311 | new->c[nr_probes].func = probe; |
| 312 | new->c[nr_probes].probe_private = probe_private; |
| 313 | entry->refcount = nr_probes + 1; |
| 314 | entry->multi = new; |
| 315 | entry->ptype = 1; |
| 316 | debug_print_probes(entry); |
| 317 | return old; |
| 318 | } |
| 319 | |
| 320 | static struct ust_marker_probe_array * |
| 321 | ust_marker_entry_remove_probe(struct ust_marker_entry *entry, |
| 322 | ust_marker_probe_func *probe, void *probe_private) |
| 323 | { |
| 324 | int nr_probes = 0, nr_del = 0, i; |
| 325 | struct ust_marker_probe_array *old, *new; |
| 326 | |
| 327 | old = entry->multi; |
| 328 | |
| 329 | debug_print_probes(entry); |
| 330 | if (!entry->ptype) { |
| 331 | /* 0 -> N is an error */ |
| 332 | WARN_ON(entry->single.func == __ust_marker_empty_function); |
| 333 | /* 1 -> 0 probes */ |
| 334 | WARN_ON(probe && entry->single.func != probe); |
| 335 | WARN_ON(entry->single.probe_private != probe_private); |
| 336 | entry->single.func = __ust_marker_empty_function; |
| 337 | entry->refcount = 0; |
| 338 | entry->ptype = 0; |
| 339 | debug_print_probes(entry); |
| 340 | return NULL; |
| 341 | } else { |
| 342 | /* (N -> M), (N > 1, M >= 0) probes */ |
| 343 | for (nr_probes = 0; old->c[nr_probes].func; nr_probes++) { |
| 344 | if ((!probe || old->c[nr_probes].func == probe) |
| 345 | && old->c[nr_probes].probe_private |
| 346 | == probe_private) |
| 347 | nr_del++; |
| 348 | } |
| 349 | } |
| 350 | |
| 351 | if (nr_probes - nr_del == 0) { |
| 352 | /* N -> 0, (N > 1) */ |
| 353 | entry->single.func = __ust_marker_empty_function; |
| 354 | entry->refcount = 0; |
| 355 | entry->ptype = 0; |
| 356 | } else if (nr_probes - nr_del == 1) { |
| 357 | /* N -> 1, (N > 1) */ |
| 358 | for (i = 0; old->c[i].func; i++) |
| 359 | if ((probe && old->c[i].func != probe) || |
| 360 | old->c[i].probe_private != probe_private) |
| 361 | entry->single = old->c[i]; |
| 362 | entry->refcount = 1; |
| 363 | entry->ptype = 0; |
| 364 | } else { |
| 365 | int j = 0; |
| 366 | /* N -> M, (N > 1, M > 1) */ |
| 367 | /* + 1 for NULL */ |
| 368 | new = zmalloc(sizeof(struct ust_marker_probe_array) |
| 369 | + ((nr_probes - nr_del + 1) * sizeof(struct ust_marker_probe_closure))); |
| 370 | if (new == NULL) |
| 371 | return ERR_PTR(-ENOMEM); |
| 372 | for (i = 0; old->c[i].func; i++) |
| 373 | if ((probe && old->c[i].func != probe) || |
| 374 | old->c[i].probe_private != probe_private) |
| 375 | new->c[j++] = old->c[i]; |
| 376 | entry->refcount = nr_probes - nr_del; |
| 377 | entry->ptype = 1; |
| 378 | entry->multi = new; |
| 379 | } |
| 380 | debug_print_probes(entry); |
| 381 | return old; |
| 382 | } |
| 383 | |
| 384 | /* |
| 385 | * Get ust_marker if the ust_marker is present in the ust_marker hash table. |
| 386 | * Must be called with ust_marker_mutex held. |
| 387 | * Returns NULL if not present. |
| 388 | */ |
| 389 | static struct ust_marker_entry *get_ust_marker(const char *channel, const char *name) |
| 390 | { |
| 391 | struct cds_hlist_head *head; |
| 392 | struct cds_hlist_node *node; |
| 393 | struct ust_marker_entry *e; |
| 394 | size_t channel_len = strlen(channel) + 1; |
| 395 | size_t name_len = strlen(name) + 1; |
| 396 | u32 hash; |
| 397 | |
| 398 | hash = jhash(channel, channel_len-1, 0) ^ jhash(name, name_len-1, 0); |
| 399 | head = &ust_marker_table[hash & ((1 << UST_MARKER_HASH_BITS)-1)]; |
| 400 | cds_hlist_for_each_entry(e, node, head, hlist) { |
| 401 | if (!strcmp(channel, e->channel) && !strcmp(name, e->name)) |
| 402 | return e; |
| 403 | } |
| 404 | return NULL; |
| 405 | } |
| 406 | |
| 407 | /* |
| 408 | * Add the ust_marker to the ust_marker hash table. Must be called with |
| 409 | * ust_marker_mutex held. |
| 410 | */ |
| 411 | static struct ust_marker_entry *add_ust_marker(const char *channel, const char *name, |
| 412 | const char *format) |
| 413 | { |
| 414 | struct cds_hlist_head *head; |
| 415 | struct cds_hlist_node *node; |
| 416 | struct ust_marker_entry *e; |
| 417 | size_t channel_len = strlen(channel) + 1; |
| 418 | size_t name_len = strlen(name) + 1; |
| 419 | size_t format_len = 0; |
| 420 | u32 hash; |
| 421 | |
| 422 | hash = jhash(channel, channel_len-1, 0) ^ jhash(name, name_len-1, 0); |
| 423 | if (format) |
| 424 | format_len = strlen(format) + 1; |
| 425 | head = &ust_marker_table[hash & ((1 << UST_MARKER_HASH_BITS)-1)]; |
| 426 | cds_hlist_for_each_entry(e, node, head, hlist) { |
| 427 | if (!strcmp(channel, e->channel) && !strcmp(name, e->name)) { |
| 428 | DBG("ust_marker %s.%s busy", channel, name); |
| 429 | return ERR_PTR(-EBUSY); /* Already there */ |
| 430 | } |
| 431 | } |
| 432 | /* |
| 433 | * Using zmalloc here to allocate a variable length element. Could |
| 434 | * cause some memory fragmentation if overused. |
| 435 | */ |
| 436 | e = zmalloc(sizeof(struct ust_marker_entry) |
| 437 | + channel_len + name_len + format_len); |
| 438 | if (!e) |
| 439 | return ERR_PTR(-ENOMEM); |
| 440 | memcpy(e->channel, channel, channel_len); |
| 441 | e->name = &e->channel[channel_len]; |
| 442 | memcpy(e->name, name, name_len); |
| 443 | if (format) { |
| 444 | e->format = &e->name[name_len]; |
| 445 | memcpy(e->format, format, format_len); |
| 446 | if (strcmp(e->format, UST_MARKER_NOARGS) == 0) |
| 447 | e->call = ust_marker_probe_cb_noarg; |
| 448 | else |
| 449 | e->call = ust_marker_probe_cb; |
| 450 | __ust_marker(metadata, core_marker_format, NULL, |
| 451 | "channel %s name %s format %s", |
| 452 | e->channel, e->name, e->format); |
| 453 | } else { |
| 454 | e->format = NULL; |
| 455 | e->call = ust_marker_probe_cb; |
| 456 | } |
| 457 | e->single.func = __ust_marker_empty_function; |
| 458 | e->single.probe_private = NULL; |
| 459 | e->multi = NULL; |
| 460 | e->ptype = 0; |
| 461 | e->format_allocated = 0; |
| 462 | e->refcount = 0; |
| 463 | cds_hlist_add_head(&e->hlist, head); |
| 464 | return e; |
| 465 | } |
| 466 | |
| 467 | /* |
| 468 | * Remove the ust_marker from the ust_marker hash table. Must be called with mutex_lock |
| 469 | * held. |
| 470 | */ |
| 471 | static int remove_ust_marker(const char *channel, const char *name) |
| 472 | { |
| 473 | struct cds_hlist_head *head; |
| 474 | struct cds_hlist_node *node; |
| 475 | struct ust_marker_entry *e; |
| 476 | int found = 0; |
| 477 | size_t channel_len = strlen(channel) + 1; |
| 478 | size_t name_len = strlen(name) + 1; |
| 479 | u32 hash; |
| 480 | int ret; |
| 481 | |
| 482 | hash = jhash(channel, channel_len-1, 0) ^ jhash(name, name_len-1, 0); |
| 483 | head = &ust_marker_table[hash & ((1 << UST_MARKER_HASH_BITS)-1)]; |
| 484 | cds_hlist_for_each_entry(e, node, head, hlist) { |
| 485 | if (!strcmp(channel, e->channel) && !strcmp(name, e->name)) { |
| 486 | found = 1; |
| 487 | break; |
| 488 | } |
| 489 | } |
| 490 | if (!found) |
| 491 | return -ENOENT; |
| 492 | if (e->single.func != __ust_marker_empty_function) |
| 493 | return -EBUSY; |
| 494 | cds_hlist_del(&e->hlist); |
| 495 | if (e->format_allocated) |
| 496 | free(e->format); |
| 497 | ret = ltt_channels_unregister(e->channel); |
| 498 | WARN_ON(ret); |
| 499 | free(e); |
| 500 | return 0; |
| 501 | } |
| 502 | |
| 503 | /* |
| 504 | * Set the mark_entry format to the format found in the element. |
| 505 | */ |
| 506 | static int ust_marker_set_format(struct ust_marker_entry *entry, const char *format) |
| 507 | { |
| 508 | entry->format = strdup(format); |
| 509 | if (!entry->format) |
| 510 | return -ENOMEM; |
| 511 | entry->format_allocated = 1; |
| 512 | |
| 513 | __ust_marker(metadata, core_marker_format, NULL, |
| 514 | "channel %s name %s format %s", |
| 515 | entry->channel, entry->name, entry->format); |
| 516 | return 0; |
| 517 | } |
| 518 | |
| 519 | /* |
| 520 | * Sets the probe callback corresponding to one ust_marker. |
| 521 | */ |
| 522 | static int set_ust_marker(struct ust_marker_entry *entry, struct ust_marker *elem, |
| 523 | int active) |
| 524 | { |
| 525 | int ret = 0; |
| 526 | WARN_ON(strcmp(entry->name, elem->name) != 0); |
| 527 | |
| 528 | if (entry->format) { |
| 529 | if (strcmp(entry->format, elem->format) != 0) { |
| 530 | ERR("Format mismatch for probe %s (%s), ust_marker (%s)", |
| 531 | entry->name, |
| 532 | entry->format, |
| 533 | elem->format); |
| 534 | return -EPERM; |
| 535 | } |
| 536 | } else { |
| 537 | ret = ust_marker_set_format(entry, elem->format); |
| 538 | if (ret) |
| 539 | return ret; |
| 540 | } |
| 541 | |
| 542 | /* |
| 543 | * probe_cb setup (statically known) is done here. It is |
| 544 | * asynchronous with the rest of execution, therefore we only |
| 545 | * pass from a "safe" callback (with argument) to an "unsafe" |
| 546 | * callback (does not set arguments). |
| 547 | */ |
| 548 | elem->call = entry->call; |
| 549 | elem->channel_id = entry->channel_id; |
| 550 | elem->event_id = entry->event_id; |
| 551 | /* |
| 552 | * Sanity check : |
| 553 | * We only update the single probe private data when the ptr is |
| 554 | * set to a _non_ single probe! (0 -> 1 and N -> 1, N != 1) |
| 555 | */ |
| 556 | WARN_ON(elem->single.func != __ust_marker_empty_function |
| 557 | && elem->single.probe_private != entry->single.probe_private |
| 558 | && !elem->ptype); |
| 559 | elem->single.probe_private = entry->single.probe_private; |
| 560 | /* |
| 561 | * Make sure the private data is valid when we update the |
| 562 | * single probe ptr. |
| 563 | */ |
| 564 | cmm_smp_wmb(); |
| 565 | elem->single.func = entry->single.func; |
| 566 | /* |
| 567 | * We also make sure that the new probe callbacks array is consistent |
| 568 | * before setting a pointer to it. |
| 569 | */ |
| 570 | rcu_assign_pointer(elem->multi, entry->multi); |
| 571 | /* |
| 572 | * Update the function or multi probe array pointer before setting the |
| 573 | * ptype. |
| 574 | */ |
| 575 | cmm_smp_wmb(); |
| 576 | elem->ptype = entry->ptype; |
| 577 | |
| 578 | if (elem->tp_name && (active ^ elem->state)) { |
| 579 | WARN_ON(!elem->tp_cb); |
| 580 | /* |
| 581 | * It is ok to directly call the probe registration because type |
| 582 | * checking has been done in the __ust_marker_tp() macro. |
| 583 | */ |
| 584 | |
| 585 | if (active) { |
| 586 | ret = tracepoint_probe_register_noupdate( |
| 587 | elem->tp_name, |
| 588 | elem->tp_cb, NULL); |
| 589 | } else { |
| 590 | /* |
| 591 | * tracepoint_probe_update_all() must be called |
| 592 | * before the library containing tp_cb is unloaded. |
| 593 | */ |
| 594 | ret = tracepoint_probe_unregister_noupdate( |
| 595 | elem->tp_name, |
| 596 | elem->tp_cb, NULL); |
| 597 | } |
| 598 | } |
| 599 | elem->state = active; |
| 600 | |
| 601 | return ret; |
| 602 | } |
| 603 | |
| 604 | /* |
| 605 | * Disable a ust_marker and its probe callback. |
| 606 | * Note: only waiting an RCU period after setting elem->call to the empty |
| 607 | * function insures that the original callback is not used anymore. This insured |
| 608 | * by rcu_read_lock around the call site. |
| 609 | */ |
| 610 | static void disable_ust_marker(struct ust_marker *elem) |
| 611 | { |
| 612 | int ret; |
| 613 | |
| 614 | /* leave "call" as is. It is known statically. */ |
| 615 | if (elem->tp_name && elem->state) { |
| 616 | WARN_ON(!elem->tp_cb); |
| 617 | /* |
| 618 | * It is ok to directly call the probe registration because type |
| 619 | * checking has been done in the __ust_marker_tp() macro. |
| 620 | */ |
| 621 | /* |
| 622 | * tracepoint_probe_update_all() must be called |
| 623 | * before the module containing tp_cb is unloaded. |
| 624 | */ |
| 625 | ret = tracepoint_probe_unregister_noupdate(elem->tp_name, |
| 626 | elem->tp_cb, NULL); |
| 627 | WARN_ON(ret); |
| 628 | } |
| 629 | elem->state = 0; |
| 630 | elem->single.func = __ust_marker_empty_function; |
| 631 | /* Update the function before setting the ptype */ |
| 632 | cmm_smp_wmb(); |
| 633 | elem->ptype = 0; /* single probe */ |
| 634 | /* |
| 635 | * Leave the private data and channel_id/event_id there, because removal |
| 636 | * is racy and should be done only after an RCU period. These are never |
| 637 | * used until the next initialization anyway. |
| 638 | */ |
| 639 | } |
| 640 | |
| 641 | /* |
| 642 | * is_ust_marker_enabled - Check if a ust_marker is enabled |
| 643 | * @channel: channel name |
| 644 | * @name: ust_marker name |
| 645 | * |
| 646 | * Returns 1 if the ust_marker is enabled, 0 if disabled. |
| 647 | */ |
| 648 | int is_ust_marker_enabled(const char *channel, const char *name) |
| 649 | { |
| 650 | struct ust_marker_entry *entry; |
| 651 | |
| 652 | lock_ust_marker(); |
| 653 | entry = get_ust_marker(channel, name); |
| 654 | unlock_ust_marker(); |
| 655 | |
| 656 | return entry && !!entry->refcount; |
| 657 | } |
| 658 | |
| 659 | /** |
| 660 | * ust_marker_update_probe_range - Update a probe range |
| 661 | * @begin: beginning of the range |
| 662 | * @end: end of the range |
| 663 | * |
| 664 | * Updates the probe callback corresponding to a range of ust_marker. |
| 665 | */ |
| 666 | static |
| 667 | void ust_marker_update_probe_range(struct ust_marker * const *begin, |
| 668 | struct ust_marker * const *end) |
| 669 | { |
| 670 | struct ust_marker * const *iter; |
| 671 | struct ust_marker_entry *mark_entry; |
| 672 | |
| 673 | for (iter = begin; iter < end; iter++) { |
| 674 | if (!*iter) |
| 675 | continue; /* skip dummy */ |
| 676 | mark_entry = get_ust_marker((*iter)->channel, (*iter)->name); |
| 677 | if (mark_entry) { |
| 678 | set_ust_marker(mark_entry, *iter, !!mark_entry->refcount); |
| 679 | /* |
| 680 | * ignore error, continue |
| 681 | */ |
| 682 | } else { |
| 683 | disable_ust_marker(*iter); |
| 684 | } |
| 685 | } |
| 686 | } |
| 687 | |
| 688 | static void lib_update_ust_marker(void) |
| 689 | { |
| 690 | struct ust_marker_lib *lib; |
| 691 | |
| 692 | lock_ust_marker(); |
| 693 | cds_list_for_each_entry(lib, &ust_marker_libs, list) |
| 694 | ust_marker_update_probe_range(lib->ust_marker_start, |
| 695 | lib->ust_marker_start + lib->ust_marker_count); |
| 696 | unlock_ust_marker(); |
| 697 | } |
| 698 | |
| 699 | /* |
| 700 | * Update probes, removing the faulty probes. |
| 701 | * |
| 702 | * Internal callback only changed before the first probe is connected to it. |
| 703 | * Single probe private data can only be changed on 0 -> 1 and 2 -> 1 |
| 704 | * transitions. All other transitions will leave the old private data valid. |
| 705 | * This makes the non-atomicity of the callback/private data updates valid. |
| 706 | * |
| 707 | * "special case" updates : |
| 708 | * 0 -> 1 callback |
| 709 | * 1 -> 0 callback |
| 710 | * 1 -> 2 callbacks |
| 711 | * 2 -> 1 callbacks |
| 712 | * Other updates all behave the same, just like the 2 -> 3 or 3 -> 2 updates. |
| 713 | * Site effect : ust_marker_set_format may delete the ust_marker entry (creating a |
| 714 | * replacement). |
| 715 | */ |
| 716 | static void ust_marker_update_probes(void) |
| 717 | { |
| 718 | lib_update_ust_marker(); |
| 719 | tracepoint_probe_update_all(); |
| 720 | } |
| 721 | |
| 722 | /** |
| 723 | * ust_marker_probe_register - Connect a probe to a ust_marker |
| 724 | * @channel: ust_marker channel |
| 725 | * @name: ust_marker name |
| 726 | * @format: format string |
| 727 | * @probe: probe handler |
| 728 | * @probe_private: probe private data |
| 729 | * |
| 730 | * private data must be a valid allocated memory address, or NULL. |
| 731 | * Returns 0 if ok, error value on error. |
| 732 | * The probe address must at least be aligned on the architecture pointer size. |
| 733 | */ |
| 734 | int ust_marker_probe_register(const char *channel, const char *name, |
| 735 | const char *format, ust_marker_probe_func *probe, |
| 736 | void *probe_private) |
| 737 | { |
| 738 | struct ust_marker_entry *entry; |
| 739 | int ret = 0, ret_err; |
| 740 | struct ust_marker_probe_array *old; |
| 741 | int first_probe = 0; |
| 742 | |
| 743 | lock_ust_marker(); |
| 744 | entry = get_ust_marker(channel, name); |
| 745 | if (!entry) { |
| 746 | first_probe = 1; |
| 747 | entry = add_ust_marker(channel, name, format); |
| 748 | if (IS_ERR(entry)) |
| 749 | ret = PTR_ERR(entry); |
| 750 | if (ret) |
| 751 | goto end; |
| 752 | ret = ltt_channels_register(channel); |
| 753 | if (ret) |
| 754 | goto error_remove_ust_marker; |
| 755 | ret = ltt_channels_get_index_from_name(channel); |
| 756 | if (ret < 0) |
| 757 | goto error_unregister_channel; |
| 758 | entry->channel_id = ret; |
| 759 | ret = ltt_channels_get_event_id(channel, name); |
| 760 | if (ret < 0) |
| 761 | goto error_unregister_channel; |
| 762 | entry->event_id = ret; |
| 763 | ret = 0; |
| 764 | __ust_marker(metadata, core_marker_id, NULL, |
| 765 | "channel %s name %s event_id %hu " |
| 766 | "int #1u%zu long #1u%zu pointer #1u%zu " |
| 767 | "size_t #1u%zu alignment #1u%u", |
| 768 | channel, name, entry->event_id, |
| 769 | sizeof(int), sizeof(long), sizeof(void *), |
| 770 | sizeof(size_t), ltt_get_alignment()); |
| 771 | } else if (format) { |
| 772 | if (!entry->format) |
| 773 | ret = ust_marker_set_format(entry, format); |
| 774 | else if (strcmp(entry->format, format)) |
| 775 | ret = -EPERM; |
| 776 | if (ret) |
| 777 | goto end; |
| 778 | } |
| 779 | |
| 780 | old = ust_marker_entry_add_probe(entry, probe, probe_private); |
| 781 | if (IS_ERR(old)) { |
| 782 | ret = PTR_ERR(old); |
| 783 | if (first_probe) |
| 784 | goto error_unregister_channel; |
| 785 | else |
| 786 | goto end; |
| 787 | } |
| 788 | unlock_ust_marker(); |
| 789 | |
| 790 | /* Activate ust_marker if necessary */ |
| 791 | ust_marker_update_probes(); |
| 792 | |
| 793 | if (old) { |
| 794 | synchronize_rcu(); |
| 795 | free_old_closure(&old->rcu); |
| 796 | } |
| 797 | return ret; |
| 798 | |
| 799 | error_unregister_channel: |
| 800 | ret_err = ltt_channels_unregister(channel); |
| 801 | WARN_ON(ret_err); |
| 802 | error_remove_ust_marker: |
| 803 | ret_err = remove_ust_marker(channel, name); |
| 804 | WARN_ON(ret_err); |
| 805 | end: |
| 806 | unlock_ust_marker(); |
| 807 | return ret; |
| 808 | } |
| 809 | |
| 810 | /** |
| 811 | * ust_marker_probe_unregister - Disconnect a probe from a ust_marker |
| 812 | * @channel: ust_marker channel |
| 813 | * @name: ust_marker name |
| 814 | * @probe: probe function pointer |
| 815 | * @probe_private: probe private data |
| 816 | * |
| 817 | * Returns the private data given to ust_marker_probe_register, or an ERR_PTR(). |
| 818 | * We do not need to call a synchronize_sched to make sure the probes have |
| 819 | * finished running before doing a module unload, because the module unload |
| 820 | * itself uses stop_machine(), which insures that every preempt disabled section |
| 821 | * have finished. |
| 822 | */ |
| 823 | int ust_marker_probe_unregister(const char *channel, const char *name, |
| 824 | ust_marker_probe_func *probe, void *probe_private) |
| 825 | { |
| 826 | struct ust_marker_entry *entry; |
| 827 | struct ust_marker_probe_array *old; |
| 828 | int ret = 0; |
| 829 | |
| 830 | lock_ust_marker(); |
| 831 | entry = get_ust_marker(channel, name); |
| 832 | if (!entry) { |
| 833 | ret = -ENOENT; |
| 834 | goto end; |
| 835 | } |
| 836 | old = ust_marker_entry_remove_probe(entry, probe, probe_private); |
| 837 | unlock_ust_marker(); |
| 838 | |
| 839 | ust_marker_update_probes(); |
| 840 | |
| 841 | if (old) { |
| 842 | synchronize_rcu(); |
| 843 | free_old_closure(&old->rcu); |
| 844 | } |
| 845 | return ret; |
| 846 | |
| 847 | end: |
| 848 | unlock_ust_marker(); |
| 849 | return ret; |
| 850 | } |
| 851 | |
| 852 | static struct ust_marker_entry * |
| 853 | get_ust_marker_from_private_data(ust_marker_probe_func *probe, |
| 854 | void *probe_private) |
| 855 | { |
| 856 | struct ust_marker_entry *entry; |
| 857 | unsigned int i; |
| 858 | struct cds_hlist_head *head; |
| 859 | struct cds_hlist_node *node; |
| 860 | |
| 861 | for (i = 0; i < UST_MARKER_TABLE_SIZE; i++) { |
| 862 | head = &ust_marker_table[i]; |
| 863 | cds_hlist_for_each_entry(entry, node, head, hlist) { |
| 864 | if (!entry->ptype) { |
| 865 | if (entry->single.func == probe |
| 866 | && entry->single.probe_private |
| 867 | == probe_private) |
| 868 | return entry; |
| 869 | } else { |
| 870 | struct ust_marker_probe_array *closure; |
| 871 | closure = entry->multi; |
| 872 | for (i = 0; closure->c[i].func; i++) { |
| 873 | if (closure->c[i].func == probe && |
| 874 | closure->c[i].probe_private |
| 875 | == probe_private) |
| 876 | return entry; |
| 877 | } |
| 878 | } |
| 879 | } |
| 880 | } |
| 881 | return NULL; |
| 882 | } |
| 883 | |
| 884 | /** |
| 885 | * ust_marker_probe_unregister_private_data - Disconnect a probe from a ust_marker |
| 886 | * @probe: probe function |
| 887 | * @probe_private: probe private data |
| 888 | * |
| 889 | * Unregister a probe by providing the registered private data. |
| 890 | * Only removes the first ust_marker found in hash table. |
| 891 | * Return 0 on success or error value. |
| 892 | * We do not need to call a synchronize_sched to make sure the probes have |
| 893 | * finished running before doing a module unload, because the module unload |
| 894 | * itself uses stop_machine(), which insures that every preempt disabled section |
| 895 | * have finished. |
| 896 | */ |
| 897 | int ust_marker_probe_unregister_private_data(ust_marker_probe_func *probe, |
| 898 | void *probe_private) |
| 899 | { |
| 900 | struct ust_marker_entry *entry; |
| 901 | int ret = 0; |
| 902 | struct ust_marker_probe_array *old; |
| 903 | char *channel = NULL, *name = NULL; |
| 904 | |
| 905 | lock_ust_marker(); |
| 906 | entry = get_ust_marker_from_private_data(probe, probe_private); |
| 907 | if (!entry) { |
| 908 | ret = -ENOENT; |
| 909 | goto unlock; |
| 910 | } |
| 911 | old = ust_marker_entry_remove_probe(entry, NULL, probe_private); |
| 912 | channel = strdup(entry->channel); |
| 913 | name = strdup(entry->name); |
| 914 | /* Ignore busy error message */ |
| 915 | remove_ust_marker(channel, name); |
| 916 | unlock_ust_marker(); |
| 917 | |
| 918 | ust_marker_update_probes(); |
| 919 | |
| 920 | if (old) { |
| 921 | synchronize_rcu(); |
| 922 | free_old_closure(&old->rcu); |
| 923 | } |
| 924 | goto end; |
| 925 | |
| 926 | unlock: |
| 927 | unlock_ust_marker(); |
| 928 | end: |
| 929 | free(channel); |
| 930 | free(name); |
| 931 | return ret; |
| 932 | } |
| 933 | |
| 934 | /** |
| 935 | * ust_marker_get_private_data - Get a ust_marker's probe private data |
| 936 | * @channel: ust_marker channel |
| 937 | * @name: ust_marker name |
| 938 | * @probe: probe to match |
| 939 | * @num: get the nth matching probe's private data |
| 940 | * |
| 941 | * Returns the nth private data pointer (starting from 0) matching, or an |
| 942 | * ERR_PTR. |
| 943 | * Returns the private data pointer, or an ERR_PTR. |
| 944 | * The private data pointer should _only_ be dereferenced if the caller is the |
| 945 | * owner of the data, or its content could vanish. This is mostly used to |
| 946 | * confirm that a caller is the owner of a registered probe. |
| 947 | */ |
| 948 | void *ust_marker_get_private_data(const char *channel, const char *name, |
| 949 | ust_marker_probe_func *probe, int num) |
| 950 | { |
| 951 | struct cds_hlist_head *head; |
| 952 | struct cds_hlist_node *node; |
| 953 | struct ust_marker_entry *e; |
| 954 | size_t channel_len = strlen(channel) + 1; |
| 955 | size_t name_len = strlen(name) + 1; |
| 956 | int i; |
| 957 | u32 hash; |
| 958 | |
| 959 | hash = jhash(channel, channel_len-1, 0) ^ jhash(name, name_len-1, 0); |
| 960 | head = &ust_marker_table[hash & ((1 << UST_MARKER_HASH_BITS)-1)]; |
| 961 | cds_hlist_for_each_entry(e, node, head, hlist) { |
| 962 | if (!strcmp(channel, e->channel) && !strcmp(name, e->name)) { |
| 963 | if (!e->ptype) { |
| 964 | if (num == 0 && e->single.func == probe) |
| 965 | return e->single.probe_private; |
| 966 | } else { |
| 967 | struct ust_marker_probe_array *closure; |
| 968 | int match = 0; |
| 969 | closure = e->multi; |
| 970 | for (i = 0; closure->c[i].func; i++) { |
| 971 | if (closure->c[i].func != probe) |
| 972 | continue; |
| 973 | if (match++ == num) |
| 974 | return closure->c[i].probe_private; |
| 975 | } |
| 976 | } |
| 977 | break; |
| 978 | } |
| 979 | } |
| 980 | return ERR_PTR(-ENOENT); |
| 981 | } |
| 982 | |
| 983 | /** |
| 984 | * ust_marker_get_iter_range - Get a next ust_marker iterator given a range. |
| 985 | * @ust_marker: current ust_marker (in), next ust_marker (out) |
| 986 | * @begin: beginning of the range |
| 987 | * @end: end of the range |
| 988 | * |
| 989 | * Returns whether a next ust_marker has been found (1) or not (0). |
| 990 | * Will return the first ust_marker in the range if the input ust_marker is NULL. |
| 991 | * Called with markers mutex held. |
| 992 | */ |
| 993 | static |
| 994 | int ust_marker_get_iter_range(struct ust_marker * const **ust_marker, |
| 995 | struct ust_marker * const *begin, |
| 996 | struct ust_marker * const *end) |
| 997 | { |
| 998 | if (!*ust_marker && begin != end) |
| 999 | *ust_marker = begin; |
| 1000 | while (*ust_marker >= begin && *ust_marker < end) { |
| 1001 | if (!**ust_marker) |
| 1002 | (*ust_marker)++; /* skip dummy */ |
| 1003 | else |
| 1004 | return 1; |
| 1005 | } |
| 1006 | return 0; |
| 1007 | } |
| 1008 | |
| 1009 | /* |
| 1010 | * Returns 0 if current not found. |
| 1011 | * Returns 1 if current found. |
| 1012 | * Called with markers mutex held. |
| 1013 | */ |
| 1014 | static |
| 1015 | int lib_get_iter_ust_marker(struct ust_marker_iter *iter) |
| 1016 | { |
| 1017 | struct ust_marker_lib *iter_lib; |
| 1018 | int found = 0; |
| 1019 | |
| 1020 | cds_list_for_each_entry(iter_lib, &ust_marker_libs, list) { |
| 1021 | if (iter_lib < iter->lib) |
| 1022 | continue; |
| 1023 | else if (iter_lib > iter->lib) |
| 1024 | iter->ust_marker = NULL; |
| 1025 | found = ust_marker_get_iter_range(&iter->ust_marker, |
| 1026 | iter_lib->ust_marker_start, |
| 1027 | iter_lib->ust_marker_start + iter_lib->ust_marker_count); |
| 1028 | if (found) { |
| 1029 | iter->lib = iter_lib; |
| 1030 | break; |
| 1031 | } |
| 1032 | } |
| 1033 | return found; |
| 1034 | } |
| 1035 | |
| 1036 | /* Called with markers mutex held. */ |
| 1037 | static void ust_marker_get_iter(struct ust_marker_iter *iter) |
| 1038 | { |
| 1039 | int found = 0; |
| 1040 | |
| 1041 | found = lib_get_iter_ust_marker(iter); |
| 1042 | if (!found) |
| 1043 | ust_marker_iter_reset(iter); |
| 1044 | } |
| 1045 | |
| 1046 | void ust_marker_iter_start(struct ust_marker_iter *iter) |
| 1047 | { |
| 1048 | lock_ust_marker(); |
| 1049 | ust_marker_get_iter(iter); |
| 1050 | } |
| 1051 | |
| 1052 | /* Called with markers mutex held. */ |
| 1053 | void ust_marker_iter_next(struct ust_marker_iter *iter) |
| 1054 | { |
| 1055 | iter->ust_marker++; |
| 1056 | /* |
| 1057 | * iter->ust_marker may be invalid because we blindly incremented it. |
| 1058 | * Make sure it is valid by marshalling on the ust_marker, getting the |
| 1059 | * ust_marker from following modules if necessary. |
| 1060 | */ |
| 1061 | ust_marker_get_iter(iter); |
| 1062 | } |
| 1063 | |
| 1064 | void ust_marker_iter_stop(struct ust_marker_iter *iter) |
| 1065 | { |
| 1066 | unlock_ust_marker(); |
| 1067 | } |
| 1068 | |
| 1069 | void ust_marker_iter_reset(struct ust_marker_iter *iter) |
| 1070 | { |
| 1071 | iter->lib = NULL; |
| 1072 | iter->ust_marker = NULL; |
| 1073 | } |
| 1074 | |
| 1075 | void ltt_dump_ust_marker_state(struct ust_trace *trace) |
| 1076 | { |
| 1077 | struct ust_marker_entry *entry; |
| 1078 | struct ltt_probe_private_data call_data; |
| 1079 | struct cds_hlist_head *head; |
| 1080 | struct cds_hlist_node *node; |
| 1081 | unsigned int i; |
| 1082 | |
| 1083 | lock_ust_marker(); |
| 1084 | call_data.trace = trace; |
| 1085 | call_data.serializer = NULL; |
| 1086 | |
| 1087 | for (i = 0; i < UST_MARKER_TABLE_SIZE; i++) { |
| 1088 | head = &ust_marker_table[i]; |
| 1089 | cds_hlist_for_each_entry(entry, node, head, hlist) { |
| 1090 | __ust_marker(metadata, core_marker_id, |
| 1091 | &call_data, |
| 1092 | "channel %s name %s event_id %hu " |
| 1093 | "int #1u%zu long #1u%zu pointer #1u%zu " |
| 1094 | "size_t #1u%zu alignment #1u%u", |
| 1095 | entry->channel, |
| 1096 | entry->name, |
| 1097 | entry->event_id, |
| 1098 | sizeof(int), sizeof(long), |
| 1099 | sizeof(void *), sizeof(size_t), |
| 1100 | ltt_get_alignment()); |
| 1101 | if (entry->format) |
| 1102 | __ust_marker(metadata, |
| 1103 | core_marker_format, |
| 1104 | &call_data, |
| 1105 | "channel %s name %s format %s", |
| 1106 | entry->channel, |
| 1107 | entry->name, |
| 1108 | entry->format); |
| 1109 | } |
| 1110 | } |
| 1111 | unlock_ust_marker(); |
| 1112 | } |
| 1113 | |
| 1114 | void ust_marker_set_new_ust_marker_cb(void (*cb)(struct ust_marker *)) |
| 1115 | { |
| 1116 | new_ust_marker_cb = cb; |
| 1117 | } |
| 1118 | |
| 1119 | static void new_ust_marker(struct ust_marker * const *start, |
| 1120 | struct ust_marker * const *end) |
| 1121 | { |
| 1122 | if (new_ust_marker_cb) { |
| 1123 | struct ust_marker * const *m; |
| 1124 | |
| 1125 | for (m = start; m < end; m++) { |
| 1126 | if (*m) |
| 1127 | new_ust_marker_cb(*m); |
| 1128 | } |
| 1129 | } |
| 1130 | } |
| 1131 | |
| 1132 | int ust_marker_register_lib(struct ust_marker * const *ust_marker_start, |
| 1133 | int ust_marker_count) |
| 1134 | { |
| 1135 | struct ust_marker_lib *pl, *iter; |
| 1136 | |
| 1137 | pl = (struct ust_marker_lib *) zmalloc(sizeof(struct ust_marker_lib)); |
| 1138 | |
| 1139 | pl->ust_marker_start = ust_marker_start; |
| 1140 | pl->ust_marker_count = ust_marker_count; |
| 1141 | |
| 1142 | lock_ust_marker(); |
| 1143 | |
| 1144 | /* |
| 1145 | * We sort the libs by struct lib pointer address. |
| 1146 | */ |
| 1147 | cds_list_for_each_entry_reverse(iter, &ust_marker_libs, list) { |
| 1148 | BUG_ON(iter == pl); /* Should never be in the list twice */ |
| 1149 | if (iter < pl) { |
| 1150 | /* We belong to the location right after iter. */ |
| 1151 | cds_list_add(&pl->list, &iter->list); |
| 1152 | goto lib_added; |
| 1153 | } |
| 1154 | } |
| 1155 | /* We should be added at the head of the list */ |
| 1156 | cds_list_add(&pl->list, &ust_marker_libs); |
| 1157 | lib_added: |
| 1158 | unlock_ust_marker(); |
| 1159 | |
| 1160 | new_ust_marker(ust_marker_start, ust_marker_start + ust_marker_count); |
| 1161 | |
| 1162 | /* TODO: update just the loaded lib */ |
| 1163 | lib_update_ust_marker(); |
| 1164 | |
| 1165 | DBG("just registered a ust_marker section from %p and having %d ust_marker (minus dummy ust_marker)", ust_marker_start, ust_marker_count); |
| 1166 | |
| 1167 | return 0; |
| 1168 | } |
| 1169 | |
| 1170 | int ust_marker_unregister_lib(struct ust_marker * const *ust_marker_start) |
| 1171 | { |
| 1172 | struct ust_marker_lib *lib; |
| 1173 | |
| 1174 | lock_ust_marker(); |
| 1175 | cds_list_for_each_entry(lib, &ust_marker_libs, list) { |
| 1176 | if(lib->ust_marker_start == ust_marker_start) { |
| 1177 | struct ust_marker_lib *lib2free = lib; |
| 1178 | cds_list_del(&lib->list); |
| 1179 | free(lib2free); |
| 1180 | break; |
| 1181 | } |
| 1182 | } |
| 1183 | unlock_ust_marker(); |
| 1184 | |
| 1185 | return 0; |
| 1186 | } |
| 1187 | |
| 1188 | void __attribute__((constructor)) init_ust_marker(void) |
| 1189 | { |
| 1190 | if (!initialized) { |
| 1191 | init_tracepoint(); |
| 1192 | ust_marker_register_lib(__start___ust_marker_ptrs, |
| 1193 | __stop___ust_marker_ptrs |
| 1194 | - __start___ust_marker_ptrs); |
| 1195 | initialized = 1; |
| 1196 | } |
| 1197 | } |
| 1198 | |
| 1199 | void __attribute__((destructor)) destroy_ust_marker(void) |
| 1200 | { |
| 1201 | ust_marker_unregister_lib(__start___ust_marker_ptrs); |
| 1202 | } |