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