| 1 | /* |
| 2 | * ltt/ltt-tracer.c |
| 3 | * |
| 4 | * Copyright (c) 2005-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 5 | * |
| 6 | * Tracing management internal kernel API. Trace buffer allocation/free, tracing |
| 7 | * start/stop. |
| 8 | * |
| 9 | * Author: |
| 10 | * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 11 | * |
| 12 | * Inspired from LTT : |
| 13 | * Karim Yaghmour (karim@opersys.com) |
| 14 | * Tom Zanussi (zanussi@us.ibm.com) |
| 15 | * Bob Wisniewski (bob@watson.ibm.com) |
| 16 | * And from K42 : |
| 17 | * Bob Wisniewski (bob@watson.ibm.com) |
| 18 | * |
| 19 | * Changelog: |
| 20 | * 22/09/06, Move to the marker/probes mechanism. |
| 21 | * 19/10/05, Complete lockless mechanism. |
| 22 | * 27/05/05, Modular redesign and rewrite. |
| 23 | * |
| 24 | * Dual LGPL v2.1/GPL v2 license. |
| 25 | */ |
| 26 | |
| 27 | #include <linux/time.h> |
| 28 | #include <linux/module.h> |
| 29 | #include <linux/string.h> |
| 30 | #include <linux/slab.h> |
| 31 | #include <linux/init.h> |
| 32 | #include <linux/rcupdate.h> |
| 33 | #include <linux/sched.h> |
| 34 | #include <linux/bitops.h> |
| 35 | #include <linux/fs.h> |
| 36 | #include <linux/cpu.h> |
| 37 | #include <linux/kref.h> |
| 38 | #include <linux/delay.h> |
| 39 | #include <linux/vmalloc.h> |
| 40 | #include <asm/atomic.h> |
| 41 | |
| 42 | #include "ltt-tracer.h" |
| 43 | |
| 44 | static void synchronize_trace(void) |
| 45 | { |
| 46 | synchronize_sched(); |
| 47 | #ifdef CONFIG_PREEMPT_RT |
| 48 | synchronize_rcu(); |
| 49 | #endif |
| 50 | } |
| 51 | |
| 52 | static void async_wakeup(unsigned long data); |
| 53 | |
| 54 | static DEFINE_TIMER(ltt_async_wakeup_timer, async_wakeup, 0, 0); |
| 55 | |
| 56 | /* Default callbacks for modules */ |
| 57 | notrace |
| 58 | int ltt_filter_control_default(enum ltt_filter_control_msg msg, |
| 59 | struct ltt_trace *trace) |
| 60 | { |
| 61 | return 0; |
| 62 | } |
| 63 | |
| 64 | int ltt_statedump_default(struct ltt_trace *trace) |
| 65 | { |
| 66 | return 0; |
| 67 | } |
| 68 | |
| 69 | /* Callbacks for registered modules */ |
| 70 | |
| 71 | int (*ltt_filter_control_functor) |
| 72 | (enum ltt_filter_control_msg msg, struct ltt_trace *trace) = |
| 73 | ltt_filter_control_default; |
| 74 | struct module *ltt_filter_control_owner; |
| 75 | |
| 76 | /* These function pointers are protected by a trace activation check */ |
| 77 | struct module *ltt_run_filter_owner; |
| 78 | int (*ltt_statedump_functor)(struct ltt_trace *trace) = ltt_statedump_default; |
| 79 | struct module *ltt_statedump_owner; |
| 80 | |
| 81 | struct chan_info_struct { |
| 82 | const char *name; |
| 83 | unsigned int def_sb_size; |
| 84 | unsigned int def_n_sb; |
| 85 | } chan_infos[] = { |
| 86 | [LTT_CHANNEL_METADATA] = { |
| 87 | LTT_METADATA_CHANNEL, |
| 88 | LTT_DEFAULT_SUBBUF_SIZE_LOW, |
| 89 | LTT_DEFAULT_N_SUBBUFS_LOW, |
| 90 | }, |
| 91 | [LTT_CHANNEL_FD_STATE] = { |
| 92 | LTT_FD_STATE_CHANNEL, |
| 93 | LTT_DEFAULT_SUBBUF_SIZE_LOW, |
| 94 | LTT_DEFAULT_N_SUBBUFS_LOW, |
| 95 | }, |
| 96 | [LTT_CHANNEL_GLOBAL_STATE] = { |
| 97 | LTT_GLOBAL_STATE_CHANNEL, |
| 98 | LTT_DEFAULT_SUBBUF_SIZE_LOW, |
| 99 | LTT_DEFAULT_N_SUBBUFS_LOW, |
| 100 | }, |
| 101 | [LTT_CHANNEL_IRQ_STATE] = { |
| 102 | LTT_IRQ_STATE_CHANNEL, |
| 103 | LTT_DEFAULT_SUBBUF_SIZE_LOW, |
| 104 | LTT_DEFAULT_N_SUBBUFS_LOW, |
| 105 | }, |
| 106 | [LTT_CHANNEL_MODULE_STATE] = { |
| 107 | LTT_MODULE_STATE_CHANNEL, |
| 108 | LTT_DEFAULT_SUBBUF_SIZE_LOW, |
| 109 | LTT_DEFAULT_N_SUBBUFS_LOW, |
| 110 | }, |
| 111 | [LTT_CHANNEL_NETIF_STATE] = { |
| 112 | LTT_NETIF_STATE_CHANNEL, |
| 113 | LTT_DEFAULT_SUBBUF_SIZE_LOW, |
| 114 | LTT_DEFAULT_N_SUBBUFS_LOW, |
| 115 | }, |
| 116 | [LTT_CHANNEL_SOFTIRQ_STATE] = { |
| 117 | LTT_SOFTIRQ_STATE_CHANNEL, |
| 118 | LTT_DEFAULT_SUBBUF_SIZE_LOW, |
| 119 | LTT_DEFAULT_N_SUBBUFS_LOW, |
| 120 | }, |
| 121 | [LTT_CHANNEL_SWAP_STATE] = { |
| 122 | LTT_SWAP_STATE_CHANNEL, |
| 123 | LTT_DEFAULT_SUBBUF_SIZE_LOW, |
| 124 | LTT_DEFAULT_N_SUBBUFS_LOW, |
| 125 | }, |
| 126 | [LTT_CHANNEL_SYSCALL_STATE] = { |
| 127 | LTT_SYSCALL_STATE_CHANNEL, |
| 128 | LTT_DEFAULT_SUBBUF_SIZE_LOW, |
| 129 | LTT_DEFAULT_N_SUBBUFS_LOW, |
| 130 | }, |
| 131 | [LTT_CHANNEL_TASK_STATE] = { |
| 132 | LTT_TASK_STATE_CHANNEL, |
| 133 | LTT_DEFAULT_SUBBUF_SIZE_LOW, |
| 134 | LTT_DEFAULT_N_SUBBUFS_LOW, |
| 135 | }, |
| 136 | [LTT_CHANNEL_VM_STATE] = { |
| 137 | LTT_VM_STATE_CHANNEL, |
| 138 | LTT_DEFAULT_SUBBUF_SIZE_MED, |
| 139 | LTT_DEFAULT_N_SUBBUFS_MED, |
| 140 | }, |
| 141 | [LTT_CHANNEL_FS] = { |
| 142 | LTT_FS_CHANNEL, |
| 143 | LTT_DEFAULT_SUBBUF_SIZE_MED, |
| 144 | LTT_DEFAULT_N_SUBBUFS_MED, |
| 145 | }, |
| 146 | [LTT_CHANNEL_INPUT] = { |
| 147 | LTT_INPUT_CHANNEL, |
| 148 | LTT_DEFAULT_SUBBUF_SIZE_LOW, |
| 149 | LTT_DEFAULT_N_SUBBUFS_LOW, |
| 150 | }, |
| 151 | [LTT_CHANNEL_IPC] = { |
| 152 | LTT_IPC_CHANNEL, |
| 153 | LTT_DEFAULT_SUBBUF_SIZE_LOW, |
| 154 | LTT_DEFAULT_N_SUBBUFS_LOW, |
| 155 | }, |
| 156 | [LTT_CHANNEL_KERNEL] = { |
| 157 | LTT_KERNEL_CHANNEL, |
| 158 | LTT_DEFAULT_SUBBUF_SIZE_HIGH, |
| 159 | LTT_DEFAULT_N_SUBBUFS_HIGH, |
| 160 | }, |
| 161 | [LTT_CHANNEL_MM] = { |
| 162 | LTT_MM_CHANNEL, |
| 163 | LTT_DEFAULT_SUBBUF_SIZE_MED, |
| 164 | LTT_DEFAULT_N_SUBBUFS_MED, |
| 165 | }, |
| 166 | [LTT_CHANNEL_RCU] = { |
| 167 | LTT_RCU_CHANNEL, |
| 168 | LTT_DEFAULT_SUBBUF_SIZE_MED, |
| 169 | LTT_DEFAULT_N_SUBBUFS_MED, |
| 170 | }, |
| 171 | [LTT_CHANNEL_DEFAULT] = { |
| 172 | NULL, |
| 173 | LTT_DEFAULT_SUBBUF_SIZE_MED, |
| 174 | LTT_DEFAULT_N_SUBBUFS_MED, |
| 175 | }, |
| 176 | }; |
| 177 | |
| 178 | static enum ltt_channels get_channel_type_from_name(const char *name) |
| 179 | { |
| 180 | int i; |
| 181 | |
| 182 | if (!name) |
| 183 | return LTT_CHANNEL_DEFAULT; |
| 184 | |
| 185 | for (i = 0; i < ARRAY_SIZE(chan_infos); i++) |
| 186 | if (chan_infos[i].name && !strcmp(name, chan_infos[i].name)) |
| 187 | return (enum ltt_channels)i; |
| 188 | |
| 189 | return LTT_CHANNEL_DEFAULT; |
| 190 | } |
| 191 | |
| 192 | /** |
| 193 | * ltt_module_register - LTT module registration |
| 194 | * @name: module type |
| 195 | * @function: callback to register |
| 196 | * @owner: module which owns the callback |
| 197 | * |
| 198 | * The module calling this registration function must ensure that no |
| 199 | * trap-inducing code will be executed by "function". E.g. vmalloc_sync_all() |
| 200 | * must be called between a vmalloc and the moment the memory is made visible to |
| 201 | * "function". This registration acts as a vmalloc_sync_all. Therefore, only if |
| 202 | * the module allocates virtual memory after its registration must it |
| 203 | * synchronize the TLBs. |
| 204 | */ |
| 205 | int ltt_module_register(enum ltt_module_function name, void *function, |
| 206 | struct module *owner) |
| 207 | { |
| 208 | int ret = 0; |
| 209 | |
| 210 | /* |
| 211 | * Make sure no page fault can be triggered by the module about to be |
| 212 | * registered. We deal with this here so we don't have to call |
| 213 | * vmalloc_sync_all() in each module's init. |
| 214 | */ |
| 215 | vmalloc_sync_all(); |
| 216 | |
| 217 | switch (name) { |
| 218 | case LTT_FUNCTION_RUN_FILTER: |
| 219 | if (ltt_run_filter_owner != NULL) { |
| 220 | ret = -EEXIST; |
| 221 | goto end; |
| 222 | } |
| 223 | ltt_filter_register((ltt_run_filter_functor)function); |
| 224 | ltt_run_filter_owner = owner; |
| 225 | break; |
| 226 | case LTT_FUNCTION_FILTER_CONTROL: |
| 227 | if (ltt_filter_control_owner != NULL) { |
| 228 | ret = -EEXIST; |
| 229 | goto end; |
| 230 | } |
| 231 | ltt_filter_control_functor = |
| 232 | (int (*)(enum ltt_filter_control_msg, |
| 233 | struct ltt_trace *))function; |
| 234 | ltt_filter_control_owner = owner; |
| 235 | break; |
| 236 | case LTT_FUNCTION_STATEDUMP: |
| 237 | if (ltt_statedump_owner != NULL) { |
| 238 | ret = -EEXIST; |
| 239 | goto end; |
| 240 | } |
| 241 | ltt_statedump_functor = |
| 242 | (int (*)(struct ltt_trace *))function; |
| 243 | ltt_statedump_owner = owner; |
| 244 | break; |
| 245 | } |
| 246 | end: |
| 247 | return ret; |
| 248 | } |
| 249 | EXPORT_SYMBOL_GPL(ltt_module_register); |
| 250 | |
| 251 | /** |
| 252 | * ltt_module_unregister - LTT module unregistration |
| 253 | * @name: module type |
| 254 | */ |
| 255 | void ltt_module_unregister(enum ltt_module_function name) |
| 256 | { |
| 257 | switch (name) { |
| 258 | case LTT_FUNCTION_RUN_FILTER: |
| 259 | ltt_filter_unregister(); |
| 260 | ltt_run_filter_owner = NULL; |
| 261 | /* Wait for preempt sections to finish */ |
| 262 | synchronize_trace(); |
| 263 | break; |
| 264 | case LTT_FUNCTION_FILTER_CONTROL: |
| 265 | ltt_filter_control_functor = ltt_filter_control_default; |
| 266 | ltt_filter_control_owner = NULL; |
| 267 | break; |
| 268 | case LTT_FUNCTION_STATEDUMP: |
| 269 | ltt_statedump_functor = ltt_statedump_default; |
| 270 | ltt_statedump_owner = NULL; |
| 271 | break; |
| 272 | } |
| 273 | |
| 274 | } |
| 275 | EXPORT_SYMBOL_GPL(ltt_module_unregister); |
| 276 | |
| 277 | static LIST_HEAD(ltt_transport_list); |
| 278 | |
| 279 | /** |
| 280 | * ltt_transport_register - LTT transport registration |
| 281 | * @transport: transport structure |
| 282 | * |
| 283 | * Registers a transport which can be used as output to extract the data out of |
| 284 | * LTTng. The module calling this registration function must ensure that no |
| 285 | * trap-inducing code will be executed by the transport functions. E.g. |
| 286 | * vmalloc_sync_all() must be called between a vmalloc and the moment the memory |
| 287 | * is made visible to the transport function. This registration acts as a |
| 288 | * vmalloc_sync_all. Therefore, only if the module allocates virtual memory |
| 289 | * after its registration must it synchronize the TLBs. |
| 290 | */ |
| 291 | void ltt_transport_register(struct ltt_transport *transport) |
| 292 | { |
| 293 | /* |
| 294 | * Make sure no page fault can be triggered by the module about to be |
| 295 | * registered. We deal with this here so we don't have to call |
| 296 | * vmalloc_sync_all() in each module's init. |
| 297 | */ |
| 298 | vmalloc_sync_all(); |
| 299 | |
| 300 | ltt_lock_traces(); |
| 301 | list_add_tail(&transport->node, <t_transport_list); |
| 302 | ltt_unlock_traces(); |
| 303 | } |
| 304 | EXPORT_SYMBOL_GPL(ltt_transport_register); |
| 305 | |
| 306 | /** |
| 307 | * ltt_transport_unregister - LTT transport unregistration |
| 308 | * @transport: transport structure |
| 309 | */ |
| 310 | void ltt_transport_unregister(struct ltt_transport *transport) |
| 311 | { |
| 312 | ltt_lock_traces(); |
| 313 | list_del(&transport->node); |
| 314 | ltt_unlock_traces(); |
| 315 | } |
| 316 | EXPORT_SYMBOL_GPL(ltt_transport_unregister); |
| 317 | |
| 318 | static inline |
| 319 | int is_channel_overwrite(enum ltt_channels chan, enum trace_mode mode) |
| 320 | { |
| 321 | switch (mode) { |
| 322 | case LTT_TRACE_NORMAL: |
| 323 | return 0; |
| 324 | case LTT_TRACE_FLIGHT: |
| 325 | switch (chan) { |
| 326 | case LTT_CHANNEL_METADATA: |
| 327 | return 0; |
| 328 | default: |
| 329 | return 1; |
| 330 | } |
| 331 | case LTT_TRACE_HYBRID: |
| 332 | switch (chan) { |
| 333 | case LTT_CHANNEL_KERNEL: |
| 334 | case LTT_CHANNEL_FS: |
| 335 | case LTT_CHANNEL_MM: |
| 336 | case LTT_CHANNEL_RCU: |
| 337 | case LTT_CHANNEL_IPC: |
| 338 | case LTT_CHANNEL_INPUT: |
| 339 | return 1; |
| 340 | default: |
| 341 | return 0; |
| 342 | } |
| 343 | default: |
| 344 | return 0; |
| 345 | } |
| 346 | } |
| 347 | |
| 348 | /** |
| 349 | * _ltt_trace_find - find a trace by given name. |
| 350 | * trace_name: trace name |
| 351 | * |
| 352 | * Returns a pointer to the trace structure, NULL if not found. |
| 353 | */ |
| 354 | static struct ltt_trace *_ltt_trace_find(const char *trace_name) |
| 355 | { |
| 356 | struct ltt_trace *trace; |
| 357 | |
| 358 | list_for_each_entry(trace, <t_traces.head, list) |
| 359 | if (!strncmp(trace->trace_name, trace_name, NAME_MAX)) |
| 360 | return trace; |
| 361 | |
| 362 | return NULL; |
| 363 | } |
| 364 | |
| 365 | /* _ltt_trace_find_setup : |
| 366 | * find a trace in setup list by given name. |
| 367 | * |
| 368 | * Returns a pointer to the trace structure, NULL if not found. |
| 369 | */ |
| 370 | struct ltt_trace *_ltt_trace_find_setup(const char *trace_name) |
| 371 | { |
| 372 | struct ltt_trace *trace; |
| 373 | |
| 374 | list_for_each_entry(trace, <t_traces.setup_head, list) |
| 375 | if (!strncmp(trace->trace_name, trace_name, NAME_MAX)) |
| 376 | return trace; |
| 377 | |
| 378 | return NULL; |
| 379 | } |
| 380 | EXPORT_SYMBOL_GPL(_ltt_trace_find_setup); |
| 381 | |
| 382 | /** |
| 383 | * ltt_release_trace - Release a LTT trace |
| 384 | * @kref : reference count on the trace |
| 385 | */ |
| 386 | void ltt_release_trace(struct kref *kref) |
| 387 | { |
| 388 | struct ltt_trace *trace = container_of(kref, struct ltt_trace, kref); |
| 389 | |
| 390 | trace->ops->remove_dirs(trace); |
| 391 | module_put(trace->transport->owner); |
| 392 | ltt_channels_trace_free(trace); |
| 393 | kfree(trace); |
| 394 | } |
| 395 | EXPORT_SYMBOL_GPL(ltt_release_trace); |
| 396 | |
| 397 | static inline void prepare_chan_size_num(unsigned int *subbuf_size, |
| 398 | unsigned int *n_subbufs) |
| 399 | { |
| 400 | /* Make sure the subbuffer size is larger than a page */ |
| 401 | *subbuf_size = max_t(unsigned int, *subbuf_size, PAGE_SIZE); |
| 402 | |
| 403 | /* round to next power of 2 */ |
| 404 | *subbuf_size = 1 << get_count_order(*subbuf_size); |
| 405 | *n_subbufs = 1 << get_count_order(*n_subbufs); |
| 406 | |
| 407 | /* Subbuf size and number must both be power of two */ |
| 408 | WARN_ON(hweight32(*subbuf_size) != 1); |
| 409 | WARN_ON(hweight32(*n_subbufs) != 1); |
| 410 | } |
| 411 | |
| 412 | int _ltt_trace_setup(const char *trace_name) |
| 413 | { |
| 414 | int err = 0; |
| 415 | struct ltt_trace *new_trace = NULL; |
| 416 | int metadata_index; |
| 417 | unsigned int chan; |
| 418 | enum ltt_channels chantype; |
| 419 | |
| 420 | if (_ltt_trace_find_setup(trace_name)) { |
| 421 | printk(KERN_ERR "LTT : Trace name %s already used.\n", |
| 422 | trace_name); |
| 423 | err = -EEXIST; |
| 424 | goto traces_error; |
| 425 | } |
| 426 | |
| 427 | if (_ltt_trace_find(trace_name)) { |
| 428 | printk(KERN_ERR "LTT : Trace name %s already used.\n", |
| 429 | trace_name); |
| 430 | err = -EEXIST; |
| 431 | goto traces_error; |
| 432 | } |
| 433 | |
| 434 | new_trace = kzalloc(sizeof(struct ltt_trace), GFP_KERNEL); |
| 435 | if (!new_trace) { |
| 436 | printk(KERN_ERR |
| 437 | "LTT : Unable to allocate memory for trace %s\n", |
| 438 | trace_name); |
| 439 | err = -ENOMEM; |
| 440 | goto traces_error; |
| 441 | } |
| 442 | strncpy(new_trace->trace_name, trace_name, NAME_MAX); |
| 443 | if (ltt_channels_trace_alloc(&new_trace->nr_channels, 0)) { |
| 444 | printk(KERN_ERR |
| 445 | "LTT : Unable to allocate memory for chaninfo %s\n", |
| 446 | trace_name); |
| 447 | err = -ENOMEM; |
| 448 | goto trace_free; |
| 449 | } |
| 450 | |
| 451 | /* |
| 452 | * Force metadata channel to no overwrite. |
| 453 | */ |
| 454 | metadata_index = ltt_channels_get_index_from_name("metadata"); |
| 455 | WARN_ON(metadata_index < 0); |
| 456 | new_trace->settings[metadata_index].overwrite = 0; |
| 457 | |
| 458 | /* |
| 459 | * Set hardcoded tracer defaults for some channels |
| 460 | */ |
| 461 | for (chan = 0; chan < new_trace->nr_channels; chan++) { |
| 462 | chantype = get_channel_type_from_name( |
| 463 | ltt_channels_get_name_from_index(chan)); |
| 464 | new_trace->settings[chan].sb_size = |
| 465 | chan_infos[chantype].def_sb_size; |
| 466 | new_trace->settings[chan].n_sb = |
| 467 | chan_infos[chantype].def_n_sb; |
| 468 | } |
| 469 | |
| 470 | list_add(&new_trace->list, <t_traces.setup_head); |
| 471 | return 0; |
| 472 | |
| 473 | trace_free: |
| 474 | kfree(new_trace); |
| 475 | traces_error: |
| 476 | return err; |
| 477 | } |
| 478 | EXPORT_SYMBOL_GPL(_ltt_trace_setup); |
| 479 | |
| 480 | |
| 481 | int ltt_trace_setup(const char *trace_name) |
| 482 | { |
| 483 | int ret; |
| 484 | ltt_lock_traces(); |
| 485 | ret = _ltt_trace_setup(trace_name); |
| 486 | ltt_unlock_traces(); |
| 487 | return ret; |
| 488 | } |
| 489 | EXPORT_SYMBOL_GPL(ltt_trace_setup); |
| 490 | |
| 491 | /* must be called from within a traces lock. */ |
| 492 | static void _ltt_trace_free(struct ltt_trace *trace) |
| 493 | { |
| 494 | list_del(&trace->list); |
| 495 | kfree(trace); |
| 496 | } |
| 497 | |
| 498 | int ltt_trace_set_type(const char *trace_name, const char *trace_type) |
| 499 | { |
| 500 | int err = 0; |
| 501 | struct ltt_trace *trace; |
| 502 | struct ltt_transport *tran_iter, *transport = NULL; |
| 503 | |
| 504 | ltt_lock_traces(); |
| 505 | |
| 506 | trace = _ltt_trace_find_setup(trace_name); |
| 507 | if (!trace) { |
| 508 | printk(KERN_ERR "LTT : Trace not found %s\n", trace_name); |
| 509 | err = -ENOENT; |
| 510 | goto traces_error; |
| 511 | } |
| 512 | |
| 513 | list_for_each_entry(tran_iter, <t_transport_list, node) { |
| 514 | if (!strcmp(tran_iter->name, trace_type)) { |
| 515 | transport = tran_iter; |
| 516 | break; |
| 517 | } |
| 518 | } |
| 519 | if (!transport) { |
| 520 | printk(KERN_ERR "LTT : Transport %s is not present.\n", |
| 521 | trace_type); |
| 522 | err = -EINVAL; |
| 523 | goto traces_error; |
| 524 | } |
| 525 | |
| 526 | trace->transport = transport; |
| 527 | |
| 528 | traces_error: |
| 529 | ltt_unlock_traces(); |
| 530 | return err; |
| 531 | } |
| 532 | EXPORT_SYMBOL_GPL(ltt_trace_set_type); |
| 533 | |
| 534 | int ltt_trace_set_channel_subbufsize(const char *trace_name, |
| 535 | const char *channel_name, |
| 536 | unsigned int size) |
| 537 | { |
| 538 | int err = 0; |
| 539 | struct ltt_trace *trace; |
| 540 | int index; |
| 541 | |
| 542 | ltt_lock_traces(); |
| 543 | |
| 544 | trace = _ltt_trace_find_setup(trace_name); |
| 545 | if (!trace) { |
| 546 | printk(KERN_ERR "LTT : Trace not found %s\n", trace_name); |
| 547 | err = -ENOENT; |
| 548 | goto traces_error; |
| 549 | } |
| 550 | |
| 551 | index = ltt_channels_get_index_from_name(channel_name); |
| 552 | if (index < 0) { |
| 553 | printk(KERN_ERR "LTT : Channel %s not found\n", channel_name); |
| 554 | err = -ENOENT; |
| 555 | goto traces_error; |
| 556 | } |
| 557 | trace->settings[index].sb_size = size; |
| 558 | |
| 559 | traces_error: |
| 560 | ltt_unlock_traces(); |
| 561 | return err; |
| 562 | } |
| 563 | EXPORT_SYMBOL_GPL(ltt_trace_set_channel_subbufsize); |
| 564 | |
| 565 | int ltt_trace_set_channel_subbufcount(const char *trace_name, |
| 566 | const char *channel_name, |
| 567 | unsigned int cnt) |
| 568 | { |
| 569 | int err = 0; |
| 570 | struct ltt_trace *trace; |
| 571 | int index; |
| 572 | |
| 573 | ltt_lock_traces(); |
| 574 | |
| 575 | trace = _ltt_trace_find_setup(trace_name); |
| 576 | if (!trace) { |
| 577 | printk(KERN_ERR "LTT : Trace not found %s\n", trace_name); |
| 578 | err = -ENOENT; |
| 579 | goto traces_error; |
| 580 | } |
| 581 | |
| 582 | index = ltt_channels_get_index_from_name(channel_name); |
| 583 | if (index < 0) { |
| 584 | printk(KERN_ERR "LTT : Channel %s not found\n", channel_name); |
| 585 | err = -ENOENT; |
| 586 | goto traces_error; |
| 587 | } |
| 588 | trace->settings[index].n_sb = cnt; |
| 589 | |
| 590 | traces_error: |
| 591 | ltt_unlock_traces(); |
| 592 | return err; |
| 593 | } |
| 594 | EXPORT_SYMBOL_GPL(ltt_trace_set_channel_subbufcount); |
| 595 | |
| 596 | int ltt_trace_set_channel_switch_timer(const char *trace_name, |
| 597 | const char *channel_name, |
| 598 | unsigned long interval) |
| 599 | { |
| 600 | int err = 0; |
| 601 | struct ltt_trace *trace; |
| 602 | int index; |
| 603 | |
| 604 | ltt_lock_traces(); |
| 605 | |
| 606 | trace = _ltt_trace_find_setup(trace_name); |
| 607 | if (!trace) { |
| 608 | printk(KERN_ERR "LTT : Trace not found %s\n", trace_name); |
| 609 | err = -ENOENT; |
| 610 | goto traces_error; |
| 611 | } |
| 612 | |
| 613 | index = ltt_channels_get_index_from_name(channel_name); |
| 614 | if (index < 0) { |
| 615 | printk(KERN_ERR "LTT : Channel %s not found\n", channel_name); |
| 616 | err = -ENOENT; |
| 617 | goto traces_error; |
| 618 | } |
| 619 | ltt_channels_trace_set_timer(&trace->settings[index], interval); |
| 620 | |
| 621 | traces_error: |
| 622 | ltt_unlock_traces(); |
| 623 | return err; |
| 624 | } |
| 625 | EXPORT_SYMBOL_GPL(ltt_trace_set_channel_switch_timer); |
| 626 | |
| 627 | int ltt_trace_set_channel_overwrite(const char *trace_name, |
| 628 | const char *channel_name, |
| 629 | unsigned int overwrite) |
| 630 | { |
| 631 | int err = 0; |
| 632 | struct ltt_trace *trace; |
| 633 | int index; |
| 634 | |
| 635 | ltt_lock_traces(); |
| 636 | |
| 637 | trace = _ltt_trace_find_setup(trace_name); |
| 638 | if (!trace) { |
| 639 | printk(KERN_ERR "LTT : Trace not found %s\n", trace_name); |
| 640 | err = -ENOENT; |
| 641 | goto traces_error; |
| 642 | } |
| 643 | |
| 644 | /* |
| 645 | * Always put the metadata channel in non-overwrite mode : |
| 646 | * This is a very low traffic channel and it can't afford to have its |
| 647 | * data overwritten : this data (marker info) is necessary to be |
| 648 | * able to read the trace. |
| 649 | */ |
| 650 | if (overwrite && !strcmp(channel_name, "metadata")) { |
| 651 | printk(KERN_ERR "LTT : Trying to set metadata channel to " |
| 652 | "overwrite mode\n"); |
| 653 | err = -EINVAL; |
| 654 | goto traces_error; |
| 655 | } |
| 656 | |
| 657 | index = ltt_channels_get_index_from_name(channel_name); |
| 658 | if (index < 0) { |
| 659 | printk(KERN_ERR "LTT : Channel %s not found\n", channel_name); |
| 660 | err = -ENOENT; |
| 661 | goto traces_error; |
| 662 | } |
| 663 | |
| 664 | trace->settings[index].overwrite = overwrite; |
| 665 | |
| 666 | traces_error: |
| 667 | ltt_unlock_traces(); |
| 668 | return err; |
| 669 | } |
| 670 | EXPORT_SYMBOL_GPL(ltt_trace_set_channel_overwrite); |
| 671 | |
| 672 | int ltt_trace_alloc(const char *trace_name) |
| 673 | { |
| 674 | int err = 0; |
| 675 | struct ltt_trace *trace; |
| 676 | int sb_size, n_sb; |
| 677 | unsigned long flags; |
| 678 | int chan; |
| 679 | const char *channel_name; |
| 680 | |
| 681 | ltt_lock_traces(); |
| 682 | |
| 683 | trace = _ltt_trace_find_setup(trace_name); |
| 684 | if (!trace) { |
| 685 | printk(KERN_ERR "LTT : Trace not found %s\n", trace_name); |
| 686 | err = -ENOENT; |
| 687 | goto traces_error; |
| 688 | } |
| 689 | |
| 690 | kref_init(&trace->kref); |
| 691 | init_waitqueue_head(&trace->kref_wq); |
| 692 | trace->active = 0; |
| 693 | get_trace_clock(); |
| 694 | trace->freq_scale = trace_clock_freq_scale(); |
| 695 | |
| 696 | if (!trace->transport) { |
| 697 | printk(KERN_ERR "LTT : Transport is not set.\n"); |
| 698 | err = -EINVAL; |
| 699 | goto transport_error; |
| 700 | } |
| 701 | if (!try_module_get(trace->transport->owner)) { |
| 702 | printk(KERN_ERR "LTT : Can't lock transport module.\n"); |
| 703 | err = -ENODEV; |
| 704 | goto transport_error; |
| 705 | } |
| 706 | trace->ops = &trace->transport->ops; |
| 707 | |
| 708 | err = trace->ops->create_dirs(trace); |
| 709 | if (err) { |
| 710 | printk(KERN_ERR "LTT : Can't create dir for trace %s.\n", |
| 711 | trace_name); |
| 712 | goto dirs_error; |
| 713 | } |
| 714 | |
| 715 | local_irq_save(flags); |
| 716 | trace->start_freq = trace_clock_frequency(); |
| 717 | trace->start_tsc = trace_clock_read64(); |
| 718 | do_gettimeofday(&trace->start_time); |
| 719 | local_irq_restore(flags); |
| 720 | |
| 721 | for (chan = 0; chan < trace->nr_channels; chan++) { |
| 722 | channel_name = ltt_channels_get_name_from_index(chan); |
| 723 | WARN_ON(!channel_name); |
| 724 | /* |
| 725 | * note: sb_size and n_sb will be overwritten with updated |
| 726 | * values by channel creation. |
| 727 | */ |
| 728 | sb_size = trace->settings[chan].sb_size; |
| 729 | n_sb = trace->settings[chan].n_sb; |
| 730 | prepare_chan_size_num(&sb_size, &n_sb); |
| 731 | trace->channels[chan] = ltt_create_channel(channel_name, |
| 732 | trace, NULL, sb_size, n_sb, |
| 733 | trace->settings[chan].overwrite, |
| 734 | trace->settings[chan].switch_timer_interval, |
| 735 | trace->settings[chan].read_timer_interval); |
| 736 | if (err != 0) { |
| 737 | printk(KERN_ERR "LTT : Can't create channel %s.\n", |
| 738 | channel_name); |
| 739 | goto create_channel_error; |
| 740 | } |
| 741 | } |
| 742 | |
| 743 | list_del(&trace->list); |
| 744 | if (list_empty(<t_traces.head)) |
| 745 | set_kernel_trace_flag_all_tasks(); |
| 746 | list_add_rcu(&trace->list, <t_traces.head); |
| 747 | synchronize_trace(); |
| 748 | |
| 749 | ltt_unlock_traces(); |
| 750 | |
| 751 | return 0; |
| 752 | |
| 753 | create_channel_error: |
| 754 | for (chan--; chan >= 0; chan--) |
| 755 | ltt_channel_destroy(trace->channels[chan]); |
| 756 | trace->ops->remove_dirs(trace); |
| 757 | |
| 758 | dirs_error: |
| 759 | module_put(trace->transport->owner); |
| 760 | transport_error: |
| 761 | put_trace_clock(); |
| 762 | traces_error: |
| 763 | ltt_unlock_traces(); |
| 764 | return err; |
| 765 | } |
| 766 | EXPORT_SYMBOL_GPL(ltt_trace_alloc); |
| 767 | |
| 768 | /* |
| 769 | * It is worked as a wrapper for current version of ltt_control.ko. |
| 770 | * We will make a new ltt_control based on debugfs, and control each channel's |
| 771 | * buffer. |
| 772 | */ |
| 773 | static |
| 774 | int ltt_trace_create(const char *trace_name, const char *trace_type, |
| 775 | enum trace_mode mode, |
| 776 | unsigned int subbuf_size_low, unsigned int n_subbufs_low, |
| 777 | unsigned int subbuf_size_med, unsigned int n_subbufs_med, |
| 778 | unsigned int subbuf_size_high, unsigned int n_subbufs_high) |
| 779 | { |
| 780 | int err = 0; |
| 781 | |
| 782 | err = ltt_trace_setup(trace_name); |
| 783 | if (IS_ERR_VALUE(err)) |
| 784 | return err; |
| 785 | |
| 786 | err = ltt_trace_set_type(trace_name, trace_type); |
| 787 | if (IS_ERR_VALUE(err)) |
| 788 | return err; |
| 789 | |
| 790 | err = ltt_trace_alloc(trace_name); |
| 791 | if (IS_ERR_VALUE(err)) |
| 792 | return err; |
| 793 | |
| 794 | return err; |
| 795 | } |
| 796 | |
| 797 | /* Must be called while sure that trace is in the list. */ |
| 798 | static int _ltt_trace_destroy(struct ltt_trace *trace) |
| 799 | { |
| 800 | int err = -EPERM; |
| 801 | |
| 802 | if (trace == NULL) { |
| 803 | err = -ENOENT; |
| 804 | goto traces_error; |
| 805 | } |
| 806 | if (trace->active) { |
| 807 | printk(KERN_ERR |
| 808 | "LTT : Can't destroy trace %s : tracer is active\n", |
| 809 | trace->trace_name); |
| 810 | err = -EBUSY; |
| 811 | goto active_error; |
| 812 | } |
| 813 | /* Everything went fine */ |
| 814 | list_del_rcu(&trace->list); |
| 815 | synchronize_trace(); |
| 816 | if (list_empty(<t_traces.head)) { |
| 817 | clear_kernel_trace_flag_all_tasks(); |
| 818 | } |
| 819 | return 0; |
| 820 | |
| 821 | /* error handling */ |
| 822 | active_error: |
| 823 | traces_error: |
| 824 | return err; |
| 825 | } |
| 826 | |
| 827 | /* Sleepable part of the destroy */ |
| 828 | static void __ltt_trace_destroy(struct ltt_trace *trace) |
| 829 | { |
| 830 | int i; |
| 831 | |
| 832 | for (i = 0; i < trace->nr_channels; i++) |
| 833 | ltt_channel_destroy(trace->channels[i]); |
| 834 | kref_put(&trace->kref, ltt_release_trace); |
| 835 | } |
| 836 | |
| 837 | int ltt_trace_destroy(const char *trace_name) |
| 838 | { |
| 839 | int err = 0; |
| 840 | struct ltt_trace *trace; |
| 841 | |
| 842 | ltt_lock_traces(); |
| 843 | |
| 844 | trace = _ltt_trace_find(trace_name); |
| 845 | if (trace) { |
| 846 | err = _ltt_trace_destroy(trace); |
| 847 | if (err) |
| 848 | goto error; |
| 849 | |
| 850 | __ltt_trace_destroy(trace); |
| 851 | ltt_unlock_traces(); |
| 852 | put_trace_clock(); |
| 853 | |
| 854 | return 0; |
| 855 | } |
| 856 | |
| 857 | trace = _ltt_trace_find_setup(trace_name); |
| 858 | if (trace) { |
| 859 | _ltt_trace_free(trace); |
| 860 | ltt_unlock_traces(); |
| 861 | return 0; |
| 862 | } |
| 863 | |
| 864 | err = -ENOENT; |
| 865 | |
| 866 | /* Error handling */ |
| 867 | error: |
| 868 | ltt_unlock_traces(); |
| 869 | return err; |
| 870 | } |
| 871 | EXPORT_SYMBOL_GPL(ltt_trace_destroy); |
| 872 | |
| 873 | /* must be called from within a traces lock. */ |
| 874 | static int _ltt_trace_start(struct ltt_trace *trace) |
| 875 | { |
| 876 | int err = 0; |
| 877 | |
| 878 | if (trace == NULL) { |
| 879 | err = -ENOENT; |
| 880 | goto traces_error; |
| 881 | } |
| 882 | if (trace->active) |
| 883 | printk(KERN_INFO "LTT : Tracing already active for trace %s\n", |
| 884 | trace->trace_name); |
| 885 | if (!try_module_get(ltt_run_filter_owner)) { |
| 886 | err = -ENODEV; |
| 887 | printk(KERN_ERR "LTT : Can't lock filter module.\n"); |
| 888 | goto get_ltt_run_filter_error; |
| 889 | } |
| 890 | trace->active = 1; |
| 891 | /* Read by trace points without protection : be careful */ |
| 892 | ltt_traces.num_active_traces++; |
| 893 | return err; |
| 894 | |
| 895 | /* error handling */ |
| 896 | get_ltt_run_filter_error: |
| 897 | traces_error: |
| 898 | return err; |
| 899 | } |
| 900 | |
| 901 | int ltt_trace_start(const char *trace_name) |
| 902 | { |
| 903 | int err = 0; |
| 904 | struct ltt_trace *trace; |
| 905 | |
| 906 | ltt_lock_traces(); |
| 907 | |
| 908 | trace = _ltt_trace_find(trace_name); |
| 909 | err = _ltt_trace_start(trace); |
| 910 | if (err) |
| 911 | goto no_trace; |
| 912 | |
| 913 | ltt_unlock_traces(); |
| 914 | |
| 915 | /* |
| 916 | * Call the kernel state dump. |
| 917 | * Events will be mixed with real kernel events, it's ok. |
| 918 | * Notice that there is no protection on the trace : that's exactly |
| 919 | * why we iterate on the list and check for trace equality instead of |
| 920 | * directly using this trace handle inside the logging function. |
| 921 | */ |
| 922 | |
| 923 | ltt_dump_marker_state(trace); |
| 924 | |
| 925 | if (!try_module_get(ltt_statedump_owner)) { |
| 926 | err = -ENODEV; |
| 927 | printk(KERN_ERR |
| 928 | "LTT : Can't lock state dump module.\n"); |
| 929 | } else { |
| 930 | ltt_statedump_functor(trace); |
| 931 | module_put(ltt_statedump_owner); |
| 932 | } |
| 933 | |
| 934 | return err; |
| 935 | |
| 936 | /* Error handling */ |
| 937 | no_trace: |
| 938 | ltt_unlock_traces(); |
| 939 | return err; |
| 940 | } |
| 941 | EXPORT_SYMBOL_GPL(ltt_trace_start); |
| 942 | |
| 943 | /* must be called from within traces lock */ |
| 944 | static int _ltt_trace_stop(struct ltt_trace *trace) |
| 945 | { |
| 946 | int err = -EPERM; |
| 947 | |
| 948 | if (trace == NULL) { |
| 949 | err = -ENOENT; |
| 950 | goto traces_error; |
| 951 | } |
| 952 | if (!trace->active) |
| 953 | printk(KERN_INFO "LTT : Tracing not active for trace %s\n", |
| 954 | trace->trace_name); |
| 955 | if (trace->active) { |
| 956 | trace->active = 0; |
| 957 | ltt_traces.num_active_traces--; |
| 958 | synchronize_trace(); /* Wait for each tracing to be finished */ |
| 959 | } |
| 960 | module_put(ltt_run_filter_owner); |
| 961 | /* Everything went fine */ |
| 962 | return 0; |
| 963 | |
| 964 | /* Error handling */ |
| 965 | traces_error: |
| 966 | return err; |
| 967 | } |
| 968 | |
| 969 | int ltt_trace_stop(const char *trace_name) |
| 970 | { |
| 971 | int err = 0; |
| 972 | struct ltt_trace *trace; |
| 973 | |
| 974 | ltt_lock_traces(); |
| 975 | trace = _ltt_trace_find(trace_name); |
| 976 | err = _ltt_trace_stop(trace); |
| 977 | ltt_unlock_traces(); |
| 978 | return err; |
| 979 | } |
| 980 | EXPORT_SYMBOL_GPL(ltt_trace_stop); |
| 981 | |
| 982 | /** |
| 983 | * ltt_control - Trace control in-kernel API |
| 984 | * @msg: Action to perform |
| 985 | * @trace_name: Trace on which the action must be done |
| 986 | * @trace_type: Type of trace (normal, flight, hybrid) |
| 987 | * @args: Arguments specific to the action |
| 988 | */ |
| 989 | int ltt_control(enum ltt_control_msg msg, const char *trace_name, |
| 990 | const char *trace_type, union ltt_control_args args) |
| 991 | { |
| 992 | int err = -EPERM; |
| 993 | |
| 994 | printk(KERN_ALERT "ltt_control : trace %s\n", trace_name); |
| 995 | switch (msg) { |
| 996 | case LTT_CONTROL_START: |
| 997 | printk(KERN_DEBUG "Start tracing %s\n", trace_name); |
| 998 | err = ltt_trace_start(trace_name); |
| 999 | break; |
| 1000 | case LTT_CONTROL_STOP: |
| 1001 | printk(KERN_DEBUG "Stop tracing %s\n", trace_name); |
| 1002 | err = ltt_trace_stop(trace_name); |
| 1003 | break; |
| 1004 | case LTT_CONTROL_CREATE_TRACE: |
| 1005 | printk(KERN_DEBUG "Creating trace %s\n", trace_name); |
| 1006 | err = ltt_trace_create(trace_name, trace_type, |
| 1007 | args.new_trace.mode, |
| 1008 | args.new_trace.subbuf_size_low, |
| 1009 | args.new_trace.n_subbufs_low, |
| 1010 | args.new_trace.subbuf_size_med, |
| 1011 | args.new_trace.n_subbufs_med, |
| 1012 | args.new_trace.subbuf_size_high, |
| 1013 | args.new_trace.n_subbufs_high); |
| 1014 | break; |
| 1015 | case LTT_CONTROL_DESTROY_TRACE: |
| 1016 | printk(KERN_DEBUG "Destroying trace %s\n", trace_name); |
| 1017 | err = ltt_trace_destroy(trace_name); |
| 1018 | break; |
| 1019 | } |
| 1020 | return err; |
| 1021 | } |
| 1022 | EXPORT_SYMBOL_GPL(ltt_control); |
| 1023 | |
| 1024 | /** |
| 1025 | * ltt_filter_control - Trace filter control in-kernel API |
| 1026 | * @msg: Action to perform on the filter |
| 1027 | * @trace_name: Trace on which the action must be done |
| 1028 | */ |
| 1029 | int ltt_filter_control(enum ltt_filter_control_msg msg, const char *trace_name) |
| 1030 | { |
| 1031 | int err; |
| 1032 | struct ltt_trace *trace; |
| 1033 | |
| 1034 | printk(KERN_DEBUG "ltt_filter_control : trace %s\n", trace_name); |
| 1035 | ltt_lock_traces(); |
| 1036 | trace = _ltt_trace_find(trace_name); |
| 1037 | if (trace == NULL) { |
| 1038 | printk(KERN_ALERT |
| 1039 | "Trace does not exist. Cannot proxy control request\n"); |
| 1040 | err = -ENOENT; |
| 1041 | goto trace_error; |
| 1042 | } |
| 1043 | if (!try_module_get(ltt_filter_control_owner)) { |
| 1044 | err = -ENODEV; |
| 1045 | goto get_module_error; |
| 1046 | } |
| 1047 | switch (msg) { |
| 1048 | case LTT_FILTER_DEFAULT_ACCEPT: |
| 1049 | printk(KERN_DEBUG |
| 1050 | "Proxy filter default accept %s\n", trace_name); |
| 1051 | err = (*ltt_filter_control_functor)(msg, trace); |
| 1052 | break; |
| 1053 | case LTT_FILTER_DEFAULT_REJECT: |
| 1054 | printk(KERN_DEBUG |
| 1055 | "Proxy filter default reject %s\n", trace_name); |
| 1056 | err = (*ltt_filter_control_functor)(msg, trace); |
| 1057 | break; |
| 1058 | default: |
| 1059 | err = -EPERM; |
| 1060 | } |
| 1061 | module_put(ltt_filter_control_owner); |
| 1062 | |
| 1063 | get_module_error: |
| 1064 | trace_error: |
| 1065 | ltt_unlock_traces(); |
| 1066 | return err; |
| 1067 | } |
| 1068 | EXPORT_SYMBOL_GPL(ltt_filter_control); |
| 1069 | |
| 1070 | int __init ltt_init(void) |
| 1071 | { |
| 1072 | /* Make sure no page fault can be triggered by this module */ |
| 1073 | vmalloc_sync_all(); |
| 1074 | init_timer_deferrable(<t_async_wakeup_timer); |
| 1075 | return 0; |
| 1076 | } |
| 1077 | |
| 1078 | module_init(ltt_init) |
| 1079 | |
| 1080 | static void __exit ltt_exit(void) |
| 1081 | { |
| 1082 | struct ltt_trace *trace; |
| 1083 | struct list_head *pos, *n; |
| 1084 | |
| 1085 | ltt_lock_traces(); |
| 1086 | /* Stop each trace, currently being read by RCU read-side */ |
| 1087 | list_for_each_entry_rcu(trace, <t_traces.head, list) |
| 1088 | _ltt_trace_stop(trace); |
| 1089 | /* Wait for quiescent state. Readers have preemption disabled. */ |
| 1090 | synchronize_trace(); |
| 1091 | /* Safe iteration is now permitted. It does not have to be RCU-safe |
| 1092 | * because no readers are left. */ |
| 1093 | list_for_each_safe(pos, n, <t_traces.head) { |
| 1094 | trace = container_of(pos, struct ltt_trace, list); |
| 1095 | /* _ltt_trace_destroy does a synchronize_trace() */ |
| 1096 | _ltt_trace_destroy(trace); |
| 1097 | __ltt_trace_destroy(trace); |
| 1098 | } |
| 1099 | /* free traces in pre-alloc status */ |
| 1100 | list_for_each_safe(pos, n, <t_traces.setup_head) { |
| 1101 | trace = container_of(pos, struct ltt_trace, list); |
| 1102 | _ltt_trace_free(trace); |
| 1103 | } |
| 1104 | |
| 1105 | ltt_unlock_traces(); |
| 1106 | } |
| 1107 | |
| 1108 | module_exit(ltt_exit) |
| 1109 | |
| 1110 | MODULE_LICENSE("GPL and additional rights"); |
| 1111 | MODULE_AUTHOR("Mathieu Desnoyers"); |
| 1112 | MODULE_DESCRIPTION("Linux Trace Toolkit Next Generation Tracer Kernel API"); |