| 1 | /* |
| 2 | * ltt-ring-buffer-client.h |
| 3 | * |
| 4 | * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 5 | * |
| 6 | * LTTng lib ring buffer client template. |
| 7 | * |
| 8 | * Dual LGPL v2.1/GPL v2 license. |
| 9 | */ |
| 10 | |
| 11 | #include <linux/module.h> |
| 12 | #include <linux/types.h> |
| 13 | #include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */ |
| 14 | #include "wrapper/trace-clock.h" |
| 15 | #include "ltt-events.h" |
| 16 | #include "ltt-tracer.h" |
| 17 | |
| 18 | /* |
| 19 | * Keep the natural field alignment for _each field_ within this structure if |
| 20 | * you ever add/remove a field from this header. Packed attribute is not used |
| 21 | * because gcc generates poor code on at least powerpc and mips. Don't ever |
| 22 | * let gcc add padding between the structure elements. |
| 23 | */ |
| 24 | struct packet_header { |
| 25 | uint32_t magic; /* |
| 26 | * Trace magic number. |
| 27 | * contains endianness information. |
| 28 | */ |
| 29 | uint8_t uuid[16]; |
| 30 | uint32_t stream_id; |
| 31 | uint64_t timestamp_begin; /* Cycle count at subbuffer start */ |
| 32 | uint64_t timestamp_end; /* Cycle count at subbuffer end */ |
| 33 | uint32_t content_size; /* Size of data in subbuffer */ |
| 34 | uint32_t packet_size; /* Subbuffer size (include padding) */ |
| 35 | uint32_t events_lost; /* |
| 36 | * Events lost in this subbuffer since |
| 37 | * the beginning of the trace. |
| 38 | * (may overflow) |
| 39 | */ |
| 40 | #if 0 |
| 41 | uint64_t start_time_sec; /* NTP-corrected start time */ |
| 42 | uint64_t start_time_usec; |
| 43 | uint64_t start_freq; /* |
| 44 | * Frequency at trace start, |
| 45 | * used all along the trace. |
| 46 | */ |
| 47 | uint32_t freq_scale; /* Frequency scaling (divisor) */ |
| 48 | #endif //0 |
| 49 | uint8_t header_end[0]; /* End of header */ |
| 50 | }; |
| 51 | |
| 52 | |
| 53 | static inline notrace u64 lib_ring_buffer_clock_read(struct channel *chan) |
| 54 | { |
| 55 | return trace_clock_read64(); |
| 56 | } |
| 57 | |
| 58 | /* |
| 59 | * record_header_size - Calculate the header size and padding necessary. |
| 60 | * @config: ring buffer instance configuration |
| 61 | * @chan: channel |
| 62 | * @offset: offset in the write buffer |
| 63 | * @data_size: size of the payload |
| 64 | * @pre_header_padding: padding to add before the header (output) |
| 65 | * @rflags: reservation flags |
| 66 | * @ctx: reservation context |
| 67 | * |
| 68 | * Returns the event header size (including padding). |
| 69 | * |
| 70 | * Important note : |
| 71 | * The event header must be 32-bits. The total offset calculated here : |
| 72 | * |
| 73 | * Alignment of header struct on 32 bits (min arch size, header size) |
| 74 | * + sizeof(header struct) (32-bits) |
| 75 | * + (opt) u16 (ext. event id) |
| 76 | * + (opt) u16 (event_size) |
| 77 | * (if event_size == LTT_MAX_SMALL_SIZE, has ext. event size) |
| 78 | * + (opt) u32 (ext. event size) |
| 79 | * + (opt) u64 full TSC (aligned on min(64-bits, arch size)) |
| 80 | * |
| 81 | * The payload must itself determine its own alignment from the biggest type it |
| 82 | * contains. |
| 83 | */ |
| 84 | static __inline__ |
| 85 | unsigned char record_header_size(const struct lib_ring_buffer_config *config, |
| 86 | struct channel *chan, size_t offset, |
| 87 | size_t data_size, size_t *pre_header_padding, |
| 88 | unsigned int rflags, |
| 89 | struct lib_ring_buffer_ctx *ctx) |
| 90 | { |
| 91 | size_t orig_offset = offset; |
| 92 | size_t padding; |
| 93 | |
| 94 | BUILD_BUG_ON(sizeof(struct event_header) != sizeof(u32)); |
| 95 | |
| 96 | padding = lib_ring_buffer_align(offset, |
| 97 | sizeof(struct event_header)); |
| 98 | offset += padding; |
| 99 | offset += sizeof(struct event_header); |
| 100 | |
| 101 | if (unlikely(rflags)) { |
| 102 | switch (rflags) { |
| 103 | case LTT_RFLAG_ID_SIZE_TSC: |
| 104 | offset += sizeof(u16) + sizeof(u16); |
| 105 | if (data_size >= LTT_MAX_SMALL_SIZE) |
| 106 | offset += sizeof(u32); |
| 107 | offset += lib_ring_buffer_align(offset, sizeof(u64)); |
| 108 | offset += sizeof(u64); |
| 109 | break; |
| 110 | case LTT_RFLAG_ID_SIZE: |
| 111 | offset += sizeof(u16) + sizeof(u16); |
| 112 | if (data_size >= LTT_MAX_SMALL_SIZE) |
| 113 | offset += sizeof(u32); |
| 114 | break; |
| 115 | case LTT_RFLAG_ID: |
| 116 | offset += sizeof(u16); |
| 117 | break; |
| 118 | } |
| 119 | } |
| 120 | |
| 121 | *pre_header_padding = padding; |
| 122 | return offset - orig_offset; |
| 123 | } |
| 124 | |
| 125 | #include "wrapper/ringbuffer/api.h" |
| 126 | |
| 127 | extern |
| 128 | void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config, |
| 129 | struct lib_ring_buffer_ctx *ctx, |
| 130 | u16 eID, u32 event_size); |
| 131 | |
| 132 | /* |
| 133 | * ltt_write_event_header |
| 134 | * |
| 135 | * Writes the event header to the offset (already aligned on 32-bits). |
| 136 | * |
| 137 | * @config: ring buffer instance configuration |
| 138 | * @ctx: reservation context |
| 139 | * @eID : event ID |
| 140 | * @event_size : size of the event, excluding the event header. |
| 141 | */ |
| 142 | static __inline__ |
| 143 | void ltt_write_event_header(const struct lib_ring_buffer_config *config, |
| 144 | struct lib_ring_buffer_ctx *ctx, |
| 145 | u16 eID, u32 event_size) |
| 146 | { |
| 147 | struct event_header header; |
| 148 | |
| 149 | if (unlikely(ctx->rflags)) |
| 150 | goto slow_path; |
| 151 | |
| 152 | header.id_time = eID << LTT_TSC_BITS; |
| 153 | header.id_time |= (u32)ctx->tsc & LTT_TSC_MASK; |
| 154 | lib_ring_buffer_write(config, ctx, &header, sizeof(header)); |
| 155 | |
| 156 | slow_path: |
| 157 | ltt_write_event_header_slow(config, ctx, eID, event_size); |
| 158 | } |
| 159 | |
| 160 | void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config, |
| 161 | struct lib_ring_buffer_ctx *ctx, |
| 162 | u16 eID, u32 event_size) |
| 163 | { |
| 164 | struct event_header header; |
| 165 | u16 small_size; |
| 166 | |
| 167 | switch (ctx->rflags) { |
| 168 | case LTT_RFLAG_ID_SIZE_TSC: |
| 169 | header.id_time = 29 << LTT_TSC_BITS; |
| 170 | break; |
| 171 | case LTT_RFLAG_ID_SIZE: |
| 172 | header.id_time = 30 << LTT_TSC_BITS; |
| 173 | break; |
| 174 | case LTT_RFLAG_ID: |
| 175 | header.id_time = 31 << LTT_TSC_BITS; |
| 176 | break; |
| 177 | default: |
| 178 | WARN_ON_ONCE(1); |
| 179 | header.id_time = 0; |
| 180 | } |
| 181 | |
| 182 | header.id_time |= (u32)ctx->tsc & LTT_TSC_MASK; |
| 183 | lib_ring_buffer_write(config, ctx, &header, sizeof(header)); |
| 184 | |
| 185 | switch (ctx->rflags) { |
| 186 | case LTT_RFLAG_ID_SIZE_TSC: |
| 187 | small_size = (u16)min_t(u32, event_size, LTT_MAX_SMALL_SIZE); |
| 188 | lib_ring_buffer_write(config, ctx, &eID, sizeof(u16)); |
| 189 | lib_ring_buffer_write(config, ctx, &small_size, sizeof(u16)); |
| 190 | if (small_size == LTT_MAX_SMALL_SIZE) |
| 191 | lib_ring_buffer_write(config, ctx, &event_size, |
| 192 | sizeof(u32)); |
| 193 | lib_ring_buffer_align_ctx(ctx, sizeof(u64)); |
| 194 | lib_ring_buffer_write(config, ctx, &ctx->tsc, sizeof(u64)); |
| 195 | break; |
| 196 | case LTT_RFLAG_ID_SIZE: |
| 197 | small_size = (u16)min_t(u32, event_size, LTT_MAX_SMALL_SIZE); |
| 198 | lib_ring_buffer_write(config, ctx, &eID, sizeof(u16)); |
| 199 | lib_ring_buffer_write(config, ctx, &small_size, sizeof(u16)); |
| 200 | if (small_size == LTT_MAX_SMALL_SIZE) |
| 201 | lib_ring_buffer_write(config, ctx, &event_size, |
| 202 | sizeof(u32)); |
| 203 | break; |
| 204 | case LTT_RFLAG_ID: |
| 205 | lib_ring_buffer_write(config, ctx, &eID, sizeof(u16)); |
| 206 | break; |
| 207 | } |
| 208 | } |
| 209 | |
| 210 | static const struct lib_ring_buffer_config client_config; |
| 211 | |
| 212 | static u64 client_ring_buffer_clock_read(struct channel *chan) |
| 213 | { |
| 214 | return lib_ring_buffer_clock_read(chan); |
| 215 | } |
| 216 | |
| 217 | static |
| 218 | size_t client_record_header_size(const struct lib_ring_buffer_config *config, |
| 219 | struct channel *chan, size_t offset, |
| 220 | size_t data_size, |
| 221 | size_t *pre_header_padding, |
| 222 | unsigned int rflags, |
| 223 | struct lib_ring_buffer_ctx *ctx) |
| 224 | { |
| 225 | return record_header_size(config, chan, offset, data_size, |
| 226 | pre_header_padding, rflags, ctx); |
| 227 | } |
| 228 | |
| 229 | /** |
| 230 | * client_packet_header_size - called on buffer-switch to a new sub-buffer |
| 231 | * |
| 232 | * Return header size without padding after the structure. Don't use packed |
| 233 | * structure because gcc generates inefficient code on some architectures |
| 234 | * (powerpc, mips..) |
| 235 | */ |
| 236 | static size_t client_packet_header_size(void) |
| 237 | { |
| 238 | return offsetof(struct packet_header, header_end); |
| 239 | } |
| 240 | |
| 241 | static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc, |
| 242 | unsigned int subbuf_idx) |
| 243 | { |
| 244 | struct channel *chan = buf->backend.chan; |
| 245 | struct packet_header *header = |
| 246 | (struct packet_header *) |
| 247 | lib_ring_buffer_offset_address(&buf->backend, |
| 248 | subbuf_idx * chan->backend.subbuf_size); |
| 249 | struct ltt_session *session = channel_get_private(chan); |
| 250 | |
| 251 | header->magic = CTF_MAGIC_NUMBER; |
| 252 | memcpy(header->uuid, session->uuid.b, sizeof(session->uuid)); |
| 253 | header->timestamp_begin = tsc; |
| 254 | header->timestamp_end = 0; |
| 255 | header->content_size = 0xFFFFFFFF; /* for debugging */ |
| 256 | header->packet_size = 0xFFFFFFFF; |
| 257 | header->events_lost = 0; |
| 258 | #if 0 |
| 259 | header->start_time_sec = ltt_chan->session->start_time.tv_sec; |
| 260 | header->start_time_usec = ltt_chan->session->start_time.tv_usec; |
| 261 | header->start_freq = ltt_chan->session->start_freq; |
| 262 | header->freq_scale = ltt_chan->session->freq_scale; |
| 263 | #endif //0 |
| 264 | } |
| 265 | |
| 266 | /* |
| 267 | * offset is assumed to never be 0 here : never deliver a completely empty |
| 268 | * subbuffer. data_size is between 1 and subbuf_size. |
| 269 | */ |
| 270 | static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc, |
| 271 | unsigned int subbuf_idx, unsigned long data_size) |
| 272 | { |
| 273 | struct channel *chan = buf->backend.chan; |
| 274 | struct packet_header *header = |
| 275 | (struct packet_header *) |
| 276 | lib_ring_buffer_offset_address(&buf->backend, |
| 277 | subbuf_idx * chan->backend.subbuf_size); |
| 278 | unsigned long records_lost = 0; |
| 279 | |
| 280 | header->timestamp_end = tsc; |
| 281 | header->content_size = data_size; |
| 282 | header->packet_size = PAGE_ALIGN(data_size); |
| 283 | records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf); |
| 284 | records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf); |
| 285 | records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf); |
| 286 | header->events_lost = records_lost; |
| 287 | } |
| 288 | |
| 289 | static int client_buffer_create(struct lib_ring_buffer *buf, void *priv, |
| 290 | int cpu, const char *name) |
| 291 | { |
| 292 | return 0; |
| 293 | } |
| 294 | |
| 295 | static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu) |
| 296 | { |
| 297 | } |
| 298 | |
| 299 | static const struct lib_ring_buffer_config client_config = { |
| 300 | .cb.ring_buffer_clock_read = client_ring_buffer_clock_read, |
| 301 | .cb.record_header_size = client_record_header_size, |
| 302 | .cb.subbuffer_header_size = client_packet_header_size, |
| 303 | .cb.buffer_begin = client_buffer_begin, |
| 304 | .cb.buffer_end = client_buffer_end, |
| 305 | .cb.buffer_create = client_buffer_create, |
| 306 | .cb.buffer_finalize = client_buffer_finalize, |
| 307 | |
| 308 | .tsc_bits = 32, |
| 309 | .alloc = RING_BUFFER_ALLOC_PER_CPU, |
| 310 | .sync = RING_BUFFER_SYNC_PER_CPU, |
| 311 | .mode = RING_BUFFER_MODE_TEMPLATE, |
| 312 | .backend = RING_BUFFER_PAGE, |
| 313 | .output = RING_BUFFER_SPLICE, |
| 314 | .oops = RING_BUFFER_OOPS_CONSISTENCY, |
| 315 | .ipi = RING_BUFFER_IPI_BARRIER, |
| 316 | .wakeup = RING_BUFFER_WAKEUP_BY_TIMER, |
| 317 | }; |
| 318 | |
| 319 | static |
| 320 | struct channel *_channel_create(const char *name, |
| 321 | struct ltt_session *session, void *buf_addr, |
| 322 | size_t subbuf_size, size_t num_subbuf, |
| 323 | unsigned int switch_timer_interval, |
| 324 | unsigned int read_timer_interval) |
| 325 | { |
| 326 | return channel_create(&client_config, name, session, buf_addr, |
| 327 | subbuf_size, num_subbuf, switch_timer_interval, |
| 328 | read_timer_interval); |
| 329 | } |
| 330 | |
| 331 | static |
| 332 | void ltt_channel_destroy(struct channel *chan) |
| 333 | { |
| 334 | channel_destroy(chan); |
| 335 | } |
| 336 | |
| 337 | static |
| 338 | struct lib_ring_buffer *ltt_buffer_read_open(struct channel *chan) |
| 339 | { |
| 340 | struct lib_ring_buffer *buf; |
| 341 | int cpu; |
| 342 | |
| 343 | for_each_channel_cpu(cpu, chan) { |
| 344 | buf = channel_get_ring_buffer(&client_config, chan, cpu); |
| 345 | if (!lib_ring_buffer_open_read(buf)) |
| 346 | return buf; |
| 347 | } |
| 348 | return NULL; |
| 349 | } |
| 350 | |
| 351 | static |
| 352 | void ltt_buffer_read_close(struct lib_ring_buffer *buf) |
| 353 | { |
| 354 | lib_ring_buffer_release_read(buf); |
| 355 | |
| 356 | } |
| 357 | |
| 358 | static |
| 359 | int ltt_event_reserve(struct lib_ring_buffer_ctx *ctx) |
| 360 | { |
| 361 | int ret, cpu; |
| 362 | |
| 363 | cpu = lib_ring_buffer_get_cpu(&client_config); |
| 364 | if (cpu < 0) |
| 365 | return -EPERM; |
| 366 | ctx->cpu = cpu; |
| 367 | |
| 368 | ret = lib_ring_buffer_reserve(&client_config, ctx); |
| 369 | if (ret) |
| 370 | goto put; |
| 371 | return ret; |
| 372 | |
| 373 | put: |
| 374 | lib_ring_buffer_put_cpu(&client_config); |
| 375 | return ret; |
| 376 | } |
| 377 | |
| 378 | static |
| 379 | void ltt_event_commit(struct lib_ring_buffer_ctx *ctx) |
| 380 | { |
| 381 | lib_ring_buffer_commit(&client_config, ctx); |
| 382 | lib_ring_buffer_put_cpu(&client_config); |
| 383 | } |
| 384 | |
| 385 | static |
| 386 | void ltt_event_write(struct lib_ring_buffer_ctx *ctx, const void *src, |
| 387 | size_t len) |
| 388 | { |
| 389 | lib_ring_buffer_write(&client_config, ctx, src, len); |
| 390 | } |
| 391 | |
| 392 | static |
| 393 | wait_queue_head_t *ltt_get_reader_wait_queue(struct ltt_channel *chan) |
| 394 | { |
| 395 | return &chan->chan->read_wait; |
| 396 | } |
| 397 | |
| 398 | static struct ltt_transport ltt_relay_transport = { |
| 399 | .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING, |
| 400 | .owner = THIS_MODULE, |
| 401 | .ops = { |
| 402 | .channel_create = _channel_create, |
| 403 | .channel_destroy = ltt_channel_destroy, |
| 404 | .buffer_read_open = ltt_buffer_read_open, |
| 405 | .buffer_read_close = ltt_buffer_read_close, |
| 406 | .event_reserve = ltt_event_reserve, |
| 407 | .event_commit = ltt_event_commit, |
| 408 | .event_write = ltt_event_write, |
| 409 | .packet_avail_size = NULL, /* Would be racy anyway */ |
| 410 | .get_reader_wait_queue = ltt_get_reader_wait_queue, |
| 411 | }, |
| 412 | }; |
| 413 | |
| 414 | static int __init ltt_ring_buffer_client_init(void) |
| 415 | { |
| 416 | /* |
| 417 | * This vmalloc sync all also takes care of the lib ring buffer |
| 418 | * vmalloc'd module pages when it is built as a module into LTTng. |
| 419 | */ |
| 420 | wrapper_vmalloc_sync_all(); |
| 421 | printk(KERN_INFO "LTT : ltt ring buffer client init\n"); |
| 422 | ltt_transport_register(<t_relay_transport); |
| 423 | return 0; |
| 424 | } |
| 425 | |
| 426 | module_init(ltt_ring_buffer_client_init); |
| 427 | |
| 428 | static void __exit ltt_ring_buffer_client_exit(void) |
| 429 | { |
| 430 | printk(KERN_INFO "LTT : ltt ring buffer client exit\n"); |
| 431 | ltt_transport_unregister(<t_relay_transport); |
| 432 | } |
| 433 | |
| 434 | module_exit(ltt_ring_buffer_client_exit); |
| 435 | |
| 436 | MODULE_LICENSE("GPL and additional rights"); |
| 437 | MODULE_AUTHOR("Mathieu Desnoyers"); |
| 438 | MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING |
| 439 | " client"); |