libust/tracer.h

   1 /*
   2  * Copyright (C) 2005,2006,2008 Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
   3  * Copyright (C) 2009 Pierre-Marc Fournier
   4  *
   5  * This contains the definitions for the Linux Trace Toolkit tracer.
   6  *
   7  * Ported to userspace by Pierre-Marc Fournier.
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  22  */
  23
  24 #ifndef _LTT_TRACER_H
  25 #define _LTT_TRACER_H
  26
  27 #include <sys/types.h>
  28 #include <stdarg.h>
  29 #include <ust/marker.h>
  30 #include <ust/marker-internal.h>
  31 #include <ust/probe-internal.h>
  32 #include <ust/core.h>
  33 #include "channels.h"
  34 #include "tracercore.h"
  35 #include "tracerconst.h"
  36 #include "buffers.h"
  37
  38 /* Number of bytes to log with a read/write event */
  39 #define LTT_LOG_RW_SIZE                 32L
  40
  41 /* Interval (in jiffies) at which the LTT per-CPU timer fires */
  42 #define LTT_PERCPU_TIMER_INTERVAL       1
  43
  44 #ifndef LTT_ARCH_TYPE
  45 #define LTT_ARCH_TYPE                   LTT_ARCH_TYPE_UNDEFINED
  46 #endif
  47
  48 #ifndef LTT_ARCH_VARIANT
  49 #define LTT_ARCH_VARIANT                LTT_ARCH_VARIANT_NONE
  50 #endif
  51
  52 struct ltt_active_ust_marker;
  53
  54 /* Maximum number of callbacks per ust_marker */
  55 #define LTT_NR_CALLBACKS        10
  56
  57 struct ltt_serialize_closure;
  58 struct ltt_probe_private_data;
  59
  60 struct ltt_serialize_closure {
  61         ltt_serialize_cb *callbacks;
  62         long cb_args[LTT_NR_CALLBACKS];
  63         unsigned int cb_idx;
  64 };
  65
  66 extern size_t ltt_serialize_data(struct ust_buffer *buf, size_t buf_offset,
  67                         struct ltt_serialize_closure *closure,
  68                         void *serialize_private,
  69                         unsigned int stack_pos_ctx, int *largest_align,
  70                         const char *fmt, va_list *args);
  71
  72 struct ltt_probe_private_data {
  73         struct ust_trace *trace;        /*
  74                                          * Target trace, for metadata
  75                                          * or statedump.
  76                                          */
  77         ltt_serialize_cb serializer;    /*
  78                                          * Serialization function override.
  79                                          */
  80         void *serialize_private;        /*
  81                                          * Private data for serialization
  82                                          * functions.
  83                                          */
  84 };
  85
  86 enum ltt_channels {
  87         LTT_CHANNEL_METADATA,
  88         LTT_CHANNEL_UST,
  89 };
  90
  91 struct chan_info_struct {
  92         const char *name;
  93         unsigned int def_subbufsize;
  94         unsigned int def_subbufcount;
  95 };
  96
  97 struct ltt_active_ust_marker {
  98         struct cds_list_head node;              /* active markers list */
  99         const char *channel;
 100         const char *name;
 101         const char *format;
 102         struct ltt_available_probe *probe;
 103 };
 104
 105 struct ust_marker; //ust//
 106 extern void ltt_vtrace(const struct ust_marker *mdata, void *probe_data,
 107         void *call_data, const char *fmt, va_list *args);
 108 extern void ltt_trace(const struct ust_marker *mdata, void *probe_data,
 109         void *call_data, const char *fmt, ...);
 110
 111 /*
 112  * Unique ID assigned to each registered probe.
 113  */
 114 enum ust_marker_id {
 115         UST_MARKER_ID_SET_MARKER_ID = 0,        /* Static IDs available (range 0-7) */
 116         UST_MARKER_ID_SET_MARKER_FORMAT,
 117         UST_MARKER_ID_COMPACT,          /* Compact IDs (range: 8-127)       */
 118         UST_MARKER_ID_DYNAMIC,          /* Dynamic IDs (range: 128-65535)   */
 119 };
 120
 121 /* static ids 0-1 reserved for internal use. */
 122 #define UST_MARKER_CORE_IDS             2
 123 static __inline__ enum ust_marker_id ust_marker_id_type(uint16_t id)
 124 {
 125         if (id < UST_MARKER_CORE_IDS)
 126                 return (enum ust_marker_id)id;
 127         else
 128                 return UST_MARKER_ID_DYNAMIC;
 129 }
 130
 131 struct user_dbg_data {
 132         unsigned long avail_size;
 133         unsigned long write;
 134         unsigned long read;
 135 };
 136
 137 struct ltt_trace_ops {
 138         /* First 32 bytes cache-hot cacheline */
 139         void (*wakeup_channel) (struct ust_channel *channel);
 140         int (*user_blocking) (struct ust_trace *trace,
 141                                 unsigned int index, size_t data_size,
 142                                 struct user_dbg_data *dbg);
 143         /* End of first 32 bytes cacheline */
 144         int (*create_dirs) (struct ust_trace *new_trace);
 145         void (*remove_dirs) (struct ust_trace *new_trace);
 146         int (*create_channel) (const char *trace_name,
 147                                 struct ust_trace *trace,
 148                                 const char *channel_name,
 149                                 struct ust_channel *channel,
 150                                 unsigned int subbuf_size,
 151                                 unsigned int n_subbufs, int overwrite);
 152         void (*finish_channel) (struct ust_channel *channel);
 153         void (*remove_channel) (struct ust_channel *channel);
 154         void (*user_errors) (struct ust_trace *trace,
 155                                 unsigned int index, size_t data_size,
 156                                 struct user_dbg_data *dbg, unsigned int cpu);
 157 };
 158
 159 struct ltt_transport {
 160         char *name;
 161         struct module *owner;
 162         struct cds_list_head node;
 163         struct ltt_trace_ops ops;
 164 };
 165
 166 enum trace_mode { LTT_TRACE_NORMAL, LTT_TRACE_FLIGHT, LTT_TRACE_HYBRID };
 167
 168 #define CHANNEL_FLAG_ENABLE     (1U<<0)
 169 #define CHANNEL_FLAG_OVERWRITE  (1U<<1)
 170
 171 /* Per-trace information - each trace/flight recorder represented by one */
 172 struct ust_trace {
 173         /* First 32 bytes cache-hot cacheline */
 174         struct cds_list_head list;
 175         struct ltt_trace_ops *ops;
 176         int active;
 177         /* Second 32 bytes cache-hot cacheline */
 178         struct ust_channel *channels;
 179         unsigned int nr_channels;
 180         u32 freq_scale;
 181         u64 start_freq;
 182         u64 start_tsc;
 183         unsigned long long start_monotonic;
 184         struct timeval          start_time;
 185         struct ltt_channel_setting *settings;
 186         struct {
 187                 struct dentry                   *trace_root;
 188         } dentry;
 189         struct urcu_ref urcu_ref; /* Each channel has a urcu_ref of the trace struct */
 190         struct ltt_transport *transport;
 191         struct urcu_ref ltt_transport_urcu_ref;
 192         char trace_name[NAME_MAX];
 193 } ____cacheline_aligned;
 194
 195 /*
 196  * We use asm/timex.h : cpu_khz/HZ variable in here : we might have to deal
 197  * specifically with CPU frequency scaling someday, so using an interpolation
 198  * between the start and end of buffer values is not flexible enough. Using an
 199  * immediate frequency value permits to calculate directly the times for parts
 200  * of a buffer that would be before a frequency change.
 201  *
 202  * Keep the natural field alignment for _each field_ within this structure if
 203  * you ever add/remove a field from this header. Packed attribute is not used
 204  * because gcc generates poor code on at least powerpc and mips. Don't ever
 205  * let gcc add padding between the structure elements.
 206  */
 207 struct ltt_subbuffer_header {
 208         uint64_t cycle_count_begin;     /* Cycle count at subbuffer start */
 209         uint64_t cycle_count_end;       /* Cycle count at subbuffer end */
 210         uint32_t magic_number;          /*
 211                                          * Trace magic number.
 212                                          * contains endianness information.
 213                                          */
 214         uint8_t major_version;
 215         uint8_t minor_version;
 216         uint8_t arch_size;              /* Architecture pointer size */
 217         uint8_t alignment;              /* LTT data alignment */
 218         uint64_t start_time_sec;        /* NTP-corrected start time */
 219         uint64_t start_time_usec;
 220         uint64_t start_freq;            /*
 221                                          * Frequency at trace start,
 222                                          * used all along the trace.
 223                                          */
 224         uint32_t freq_scale;            /* Frequency scaling (divisor) */
 225         uint32_t data_size;             /* Size of data in subbuffer */
 226         uint32_t sb_size;               /* Subbuffer size (including padding) */
 227         uint32_t events_lost;           /*
 228                                          * Events lost in this subbuffer since
 229                                          * the beginning of the trace.
 230                                          * (may overflow)
 231                                          */
 232         uint32_t subbuf_corrupt;        /*
 233                                          * Corrupted (lost) subbuffers since
 234                                          * the begginig of the trace.
 235                                          * (may overflow)
 236                                          */
 237         uint8_t header_end[0];          /* End of header */
 238 };
 239
 240 /**
 241  * ltt_subbuffer_header_size - called on buffer-switch to a new sub-buffer
 242  *
 243  * Return header size without padding after the structure. Don't use packed
 244  * structure because gcc generates inefficient code on some architectures
 245  * (powerpc, mips..)
 246  */
 247 static __inline__ size_t ltt_subbuffer_header_size(void)
 248 {
 249         return offsetof(struct ltt_subbuffer_header, header_end);
 250 }
 251
 252 extern size_t ltt_write_event_header_slow(struct ust_channel *channel,
 253                struct ust_buffer *buf, long buf_offset,
 254                u16 eID, u32 event_size,
 255                u64 tsc, unsigned int rflags);
 256
 257
 258 /*
 259  * ltt_write_event_header
 260  *
 261  * Writes the event header to the offset (already aligned on 32-bits).
 262  *
 263  * @trace : trace to write to.
 264  * @channel : pointer to the channel structure..
 265  * @buf : buffer to write to.
 266  * @buf_offset : buffer offset to write to (aligned on 32 bits).
 267  * @eID : event ID
 268  * @event_size : size of the event, excluding the event header.
 269  * @tsc : time stamp counter.
 270  * @rflags : reservation flags.
 271  *
 272  * returns : offset where the event data must be written.
 273  */
 274 static __inline__ size_t ltt_write_event_header(struct ust_channel *chan,
 275                 struct ust_buffer *buf, long buf_offset,
 276                 u16 eID, u32 event_size,
 277                 u64 tsc, unsigned int rflags)
 278 {
 279         struct ltt_event_header header;
 280
 281         if (unlikely(rflags))
 282                 goto slow_path;
 283
 284         header.id_time = eID << LTT_TSC_BITS;
 285         header.id_time |= (u32)tsc & LTT_TSC_MASK;
 286         ust_buffers_write(buf, buf_offset, &header, sizeof(header));
 287         buf_offset += sizeof(header);
 288
 289         return buf_offset;
 290
 291 slow_path:
 292         return ltt_write_event_header_slow(chan, buf, buf_offset,
 293                                 eID, event_size, tsc, rflags);
 294 }
 295
 296 /*
 297  * Control channels :
 298  * control/metadata
 299  * control/interrupts
 300  * control/...
 301  *
 302  * cpu channel :
 303  * cpu
 304  */
 305
 306 #define LTT_METADATA_CHANNEL            "metadata_state"
 307 #define LTT_UST_CHANNEL                 "ust"
 308
 309 #define LTT_FLIGHT_PREFIX       "flight-"
 310
 311 /* Tracer properties */
 312 //#define LTT_DEFAULT_SUBBUF_SIZE_LOW   134217728
 313 #define LTT_DEFAULT_SUBBUF_SIZE_LOW     65536
 314 //#define LTT_DEFAULT_SUBBUF_SIZE_LOW   4096
 315 #define LTT_DEFAULT_N_SUBBUFS_LOW       2
 316 //#define LTT_DEFAULT_SUBBUF_SIZE_MED   134217728
 317 #define LTT_DEFAULT_SUBBUF_SIZE_MED     262144
 318 //#define LTT_DEFAULT_SUBBUF_SIZE_MED   4096
 319 #define LTT_DEFAULT_N_SUBBUFS_MED       2
 320 //#define LTT_DEFAULT_SUBBUF_SIZE_HIGH  134217728
 321 #define LTT_DEFAULT_SUBBUF_SIZE_HIGH    1048576
 322 //#define LTT_DEFAULT_SUBBUF_SIZE_HIGH  4096
 323 #define LTT_DEFAULT_N_SUBBUFS_HIGH      2
 324 #define LTT_TRACER_MAGIC_NUMBER         0x00D6B7ED
 325 #define LTT_TRACER_VERSION_MAJOR        2
 326 #define LTT_TRACER_VERSION_MINOR        6
 327
 328 /**
 329  * ust_write_trace_header - Write trace header
 330  * @trace: Trace information
 331  * @header: Memory address where the information must be written to
 332  */
 333 static __inline__ void ltt_write_trace_header(struct ust_trace *trace,
 334                struct ltt_subbuffer_header *header)
 335 {
 336         header->magic_number = LTT_TRACER_MAGIC_NUMBER;
 337         header->major_version = LTT_TRACER_VERSION_MAJOR;
 338         header->minor_version = LTT_TRACER_VERSION_MINOR;
 339         header->arch_size = sizeof(void *);
 340         header->alignment = ltt_get_alignment();
 341         header->start_time_sec = trace->start_time.tv_sec;
 342         header->start_time_usec = trace->start_time.tv_usec;
 343         header->start_freq = trace->start_freq;
 344         header->freq_scale = trace->freq_scale;
 345 }
 346
 347 #ifndef UST_VALGRIND
 348
 349 static __inline__ int ust_get_cpu(void)
 350 {
 351         int cpu;
 352
 353         cpu = sched_getcpu();
 354         if (likely(cpu >= 0))
 355                 return cpu;
 356         /*
 357          * If getcpu(2) is not implemented in the Kernel use CPU 0 as fallback.
 358          */
 359         return 0;
 360 }
 361
 362 #else   /* #else #ifndef UST_VALGRIND */
 363
 364 static __inline__ int ust_get_cpu(void)
 365 {
 366         /*
 367          * Valgrind does not support the sched_getcpu() vsyscall.
 368          * It causes it to detect a segfault in the program and stop it.
 369          * So if we want to check libust with valgrind, we have to refrain
 370          * from using this call. TODO: it would probably be better to return
 371          * other values too, to better test it.
 372          */
 373         return 0;
 374 }
 375
 376 #endif  /* #else #ifndef UST_VALGRIND */
 377
 378 /*
 379  * Size reserved for high priority events (interrupts, NMI, BH) at the end of a
 380  * nearly full buffer. User space won't use this last amount of space when in
 381  * blocking mode. This space also includes the event header that would be
 382  * written by this user space event.
 383  */
 384 #define LTT_RESERVE_CRITICAL            4096
 385
 386 /* Register and unregister function pointers */
 387
 388 enum ltt_module_function {
 389         LTT_FUNCTION_RUN_FILTER,
 390         LTT_FUNCTION_FILTER_CONTROL,
 391         LTT_FUNCTION_STATEDUMP
 392 };
 393
 394 extern void ltt_transport_register(struct ltt_transport *transport);
 395 extern void ltt_transport_unregister(struct ltt_transport *transport);
 396
 397 /* Exported control function */
 398
 399 union ltt_control_args {
 400         struct {
 401                 enum trace_mode mode;
 402                 unsigned int subbuf_size_low;
 403                 unsigned int n_subbufs_low;
 404                 unsigned int subbuf_size_med;
 405                 unsigned int n_subbufs_med;
 406                 unsigned int subbuf_size_high;
 407                 unsigned int n_subbufs_high;
 408         } new_trace;
 409 };
 410
 411 extern int _ltt_trace_setup(const char *trace_name);
 412 extern int ltt_trace_setup(const char *trace_name);
 413 extern struct ust_trace *_ltt_trace_find_setup(const char *trace_name);
 414 extern int ltt_trace_set_type(const char *trace_name, const char *trace_type);
 415 extern int ltt_trace_set_channel_subbufsize(const char *trace_name,
 416                 const char *channel_name, unsigned int size);
 417 extern int ltt_trace_set_channel_subbufcount(const char *trace_name,
 418                 const char *channel_name, unsigned int cnt);
 419 extern int ltt_trace_set_channel_enable(const char *trace_name,
 420                 const char *channel_name, unsigned int enable);
 421 extern int ltt_trace_set_channel_overwrite(const char *trace_name,
 422                 const char *channel_name, unsigned int overwrite);
 423 extern int ltt_trace_alloc(const char *trace_name);
 424 extern int ltt_trace_destroy(const char *trace_name, int drop);
 425 extern int ltt_trace_start(const char *trace_name);
 426 extern int ltt_trace_stop(const char *trace_name);
 427
 428 enum ltt_filter_control_msg {
 429         LTT_FILTER_DEFAULT_ACCEPT,
 430         LTT_FILTER_DEFAULT_REJECT
 431 };
 432
 433 extern int ltt_filter_control(enum ltt_filter_control_msg msg,
 434                 const char *trace_name);
 435
 436 extern struct dentry *get_filter_root(void);
 437
 438 extern void ltt_write_trace_header(struct ust_trace *trace,
 439                 struct ltt_subbuffer_header *header);
 440 extern void ltt_buffer_destroy(struct ust_channel *ltt_chan);
 441
 442 extern void ltt_core_register(int (*function)(u8, void *));
 443
 444 extern void ltt_core_unregister(void);
 445
 446 extern void ltt_release_trace(struct urcu_ref *urcu_ref);
 447 extern void ltt_release_transport(struct urcu_ref *urcu_ref);
 448
 449 extern void ltt_dump_ust_marker_state(struct ust_trace *trace);
 450
 451 extern void ltt_lock_traces(void);
 452 extern void ltt_unlock_traces(void);
 453
 454 extern struct ust_trace *_ltt_trace_find(const char *trace_name);
 455
 456 #endif /* _LTT_TRACER_H */