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