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