libtracing/tracer.h

   1 /*
   2  * Copyright (C) 2005,2006,2008 Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
   3  *
   4  * This contains the definitions for the Linux Trace Toolkit tracer.
   5  */
   6
   7 #ifndef _LTT_TRACER_H
   8 #define _LTT_TRACER_H
   9
  10 #include <stdarg.h>
  11 #include <linux/types.h>
  12 #include <linux/limits.h>
  13 #include <linux/list.h>
  14 #include <linux/cache.h>
  15 #include <linux/kernel.h>
  16 #include <linux/timex.h>
  17 #include <linux/wait.h>
  18 #include <linux/ltt-relay.h>
  19 #include <linux/ltt-channels.h>
  20 #include <linux/ltt-core.h>
  21 #include <linux/marker.h>
  22 #include <linux/trace-clock.h>
  23 #include <asm/atomic.h>
  24 #include <asm/local.h>
  25
  26 /* Number of bytes to log with a read/write event */
  27 #define LTT_LOG_RW_SIZE                 32L
  28
  29 /* Interval (in jiffies) at which the LTT per-CPU timer fires */
  30 #define LTT_PERCPU_TIMER_INTERVAL       1
  31
  32 #ifndef LTT_ARCH_TYPE
  33 #define LTT_ARCH_TYPE                   LTT_ARCH_TYPE_UNDEFINED
  34 #endif
  35
  36 #ifndef LTT_ARCH_VARIANT
  37 #define LTT_ARCH_VARIANT                LTT_ARCH_VARIANT_NONE
  38 #endif
  39
  40 struct ltt_active_marker;
  41
  42 /* Maximum number of callbacks per marker */
  43 #define LTT_NR_CALLBACKS        10
  44
  45 struct ltt_serialize_closure;
  46 struct ltt_probe_private_data;
  47
  48 /* Serialization callback '%k' */
  49 typedef size_t (*ltt_serialize_cb)(struct rchan_buf *buf, size_t buf_offset,
  50                         struct ltt_serialize_closure *closure,
  51                         void *serialize_private, int *largest_align,
  52                         const char *fmt, va_list *args);
  53
  54 struct ltt_serialize_closure {
  55         ltt_serialize_cb *callbacks;
  56         long cb_args[LTT_NR_CALLBACKS];
  57         unsigned int cb_idx;
  58 };
  59
  60 size_t ltt_serialize_data(struct rchan_buf *buf, size_t buf_offset,
  61                         struct ltt_serialize_closure *closure,
  62                         void *serialize_private,
  63                         int *largest_align, const char *fmt, va_list *args);
  64
  65 struct ltt_available_probe {
  66         const char *name;               /* probe name */
  67         const char *format;
  68         marker_probe_func *probe_func;
  69         ltt_serialize_cb callbacks[LTT_NR_CALLBACKS];
  70         struct list_head node;          /* registered probes list */
  71 };
  72
  73 struct ltt_probe_private_data {
  74         struct ltt_trace_struct *trace; /*
  75                                          * Target trace, for metadata
  76                                          * or statedump.
  77                                          */
  78         ltt_serialize_cb serializer;    /*
  79                                          * Serialization function override.
  80                                          */
  81         void *serialize_private;        /*
  82                                          * Private data for serialization
  83                                          * functions.
  84                                          */
  85 };
  86
  87 enum ltt_channels {
  88         LTT_CHANNEL_METADATA,
  89         LTT_CHANNEL_FD_STATE,
  90         LTT_CHANNEL_GLOBAL_STATE,
  91         LTT_CHANNEL_IRQ_STATE,
  92         LTT_CHANNEL_MODULE_STATE,
  93         LTT_CHANNEL_NETIF_STATE,
  94         LTT_CHANNEL_SOFTIRQ_STATE,
  95         LTT_CHANNEL_SWAP_STATE,
  96         LTT_CHANNEL_SYSCALL_STATE,
  97         LTT_CHANNEL_TASK_STATE,
  98         LTT_CHANNEL_VM_STATE,
  99         LTT_CHANNEL_FS,
 100         LTT_CHANNEL_INPUT,
 101         LTT_CHANNEL_IPC,
 102         LTT_CHANNEL_KERNEL,
 103         LTT_CHANNEL_MM,
 104         LTT_CHANNEL_RCU,
 105         LTT_CHANNEL_DEFAULT,
 106 };
 107
 108 struct ltt_active_marker {
 109         struct list_head node;          /* active markers list */
 110         const char *channel;
 111         const char *name;
 112         const char *format;
 113         struct ltt_available_probe *probe;
 114 };
 115
 116 extern void ltt_vtrace(const struct marker *mdata, void *probe_data,
 117         void *call_data, const char *fmt, va_list *args);
 118 extern void ltt_trace(const struct marker *mdata, void *probe_data,
 119         void *call_data, const char *fmt, ...);
 120
 121 /*
 122  * Unique ID assigned to each registered probe.
 123  */
 124 enum marker_id {
 125         MARKER_ID_SET_MARKER_ID = 0,    /* Static IDs available (range 0-7) */
 126         MARKER_ID_SET_MARKER_FORMAT,
 127         MARKER_ID_COMPACT,              /* Compact IDs (range: 8-127)       */
 128         MARKER_ID_DYNAMIC,              /* Dynamic IDs (range: 128-65535)   */
 129 };
 130
 131 /* static ids 0-1 reserved for internal use. */
 132 #define MARKER_CORE_IDS         2
 133 static inline enum marker_id marker_id_type(uint16_t id)
 134 {
 135         if (id < MARKER_CORE_IDS)
 136                 return (enum marker_id)id;
 137         else
 138                 return MARKER_ID_DYNAMIC;
 139 }
 140
 141 #ifdef CONFIG_LTT
 142
 143 struct user_dbg_data {
 144         unsigned long avail_size;
 145         unsigned long write;
 146         unsigned long read;
 147 };
 148
 149 struct ltt_trace_ops {
 150         /* First 32 bytes cache-hot cacheline */
 151         int (*reserve_slot) (struct ltt_trace_struct *trace,
 152                                 struct ltt_channel_struct *channel,
 153                                 void **transport_data, size_t data_size,
 154                                 size_t *slot_size, long *buf_offset, u64 *tsc,
 155                                 unsigned int *rflags,
 156                                 int largest_align,
 157                                 int cpu);
 158         void (*commit_slot) (struct ltt_channel_struct *channel,
 159                                 void **transport_data, long buf_offset,
 160                                 size_t slot_size);
 161         void (*wakeup_channel) (struct ltt_channel_struct *ltt_channel);
 162         int (*user_blocking) (struct ltt_trace_struct *trace,
 163                                 unsigned int index, size_t data_size,
 164                                 struct user_dbg_data *dbg);
 165         /* End of first 32 bytes cacheline */
 166         int (*create_dirs) (struct ltt_trace_struct *new_trace);
 167         void (*remove_dirs) (struct ltt_trace_struct *new_trace);
 168         int (*create_channel) (const char *trace_name,
 169                                 struct ltt_trace_struct *trace,
 170                                 struct dentry *dir, const char *channel_name,
 171                                 struct ltt_channel_struct *ltt_chan,
 172                                 unsigned int subbuf_size,
 173                                 unsigned int n_subbufs, int overwrite);
 174         void (*finish_channel) (struct ltt_channel_struct *channel);
 175         void (*remove_channel) (struct ltt_channel_struct *channel);
 176         void (*user_errors) (struct ltt_trace_struct *trace,
 177                                 unsigned int index, size_t data_size,
 178                                 struct user_dbg_data *dbg, int cpu);
 179 #ifdef CONFIG_HOTPLUG_CPU
 180         int (*handle_cpuhp) (struct notifier_block *nb,
 181                                 unsigned long action, void *hcpu,
 182                                 struct ltt_trace_struct *trace);
 183 #endif
 184 } ____cacheline_aligned;
 185
 186 struct ltt_transport {
 187         char *name;
 188         struct module *owner;
 189         struct list_head node;
 190         struct ltt_trace_ops ops;
 191 };
 192
 193 enum trace_mode { LTT_TRACE_NORMAL, LTT_TRACE_FLIGHT, LTT_TRACE_HYBRID };
 194
 195 #define CHANNEL_FLAG_ENABLE     (1U<<0)
 196 #define CHANNEL_FLAG_OVERWRITE  (1U<<1)
 197
 198 /* Per-trace information - each trace/flight recorder represented by one */
 199 struct ltt_trace_struct {
 200         /* First 32 bytes cache-hot cacheline */
 201         struct list_head list;
 202         struct ltt_trace_ops *ops;
 203         int active;
 204         /* Second 32 bytes cache-hot cacheline */
 205         struct ltt_channel_struct *channels;
 206         unsigned int nr_channels;
 207         u32 freq_scale;
 208         u64 start_freq;
 209         u64 start_tsc;
 210         unsigned long long start_monotonic;
 211         struct timeval          start_time;
 212         struct ltt_channel_setting *settings;
 213         struct {
 214                 struct dentry                   *trace_root;
 215         } dentry;
 216         struct rchan_callbacks callbacks;
 217         struct kref kref; /* Each channel has a kref of the trace struct */
 218         struct ltt_transport *transport;
 219         struct kref ltt_transport_kref;
 220         wait_queue_head_t kref_wq; /* Place for ltt_trace_destroy to sleep */
 221         char trace_name[NAME_MAX];
 222 } ____cacheline_aligned;
 223
 224 /* Hardcoded event headers
 225  *
 226  * event header for a trace with active heartbeat : 27 bits timestamps
 227  *
 228  * headers are 32-bits aligned. In order to insure such alignment, a dynamic per
 229  * trace alignment value must be done.
 230  *
 231  * Remember that the C compiler does align each member on the boundary
 232  * equivalent to their own size.
 233  *
 234  * As relay subbuffers are aligned on pages, we are sure that they are 4 and 8
 235  * bytes aligned, so the buffer header and trace header are aligned.
 236  *
 237  * Event headers are aligned depending on the trace alignment option.
 238  *
 239  * Note using C structure bitfields for cross-endianness and portability
 240  * concerns.
 241  */
 242
 243 #define LTT_RESERVED_EVENTS     3
 244 #define LTT_EVENT_BITS          5
 245 #define LTT_FREE_EVENTS         ((1 << LTT_EVENT_BITS) - LTT_RESERVED_EVENTS)
 246 #define LTT_TSC_BITS            27
 247 #define LTT_TSC_MASK            ((1 << LTT_TSC_BITS) - 1)
 248
 249 struct ltt_event_header {
 250         u32 id_time;            /* 5 bits event id (MSB); 27 bits time (LSB) */
 251 };
 252
 253 /* Reservation flags */
 254 #define LTT_RFLAG_ID                    (1 << 0)
 255 #define LTT_RFLAG_ID_SIZE               (1 << 1)
 256 #define LTT_RFLAG_ID_SIZE_TSC           (1 << 2)
 257
 258 /*
 259  * We use asm/timex.h : cpu_khz/HZ variable in here : we might have to deal
 260  * specifically with CPU frequency scaling someday, so using an interpolation
 261  * between the start and end of buffer values is not flexible enough. Using an
 262  * immediate frequency value permits to calculate directly the times for parts
 263  * of a buffer that would be before a frequency change.
 264  *
 265  * Keep the natural field alignment for _each field_ within this structure if
 266  * you ever add/remove a field from this header. Packed attribute is not used
 267  * because gcc generates poor code on at least powerpc and mips. Don't ever
 268  * let gcc add padding between the structure elements.
 269  */
 270 struct ltt_subbuffer_header {
 271         uint64_t cycle_count_begin;     /* Cycle count at subbuffer start */
 272         uint64_t cycle_count_end;       /* Cycle count at subbuffer end */
 273         uint32_t magic_number;          /*
 274                                          * Trace magic number.
 275                                          * contains endianness information.
 276                                          */
 277         uint8_t major_version;
 278         uint8_t minor_version;
 279         uint8_t arch_size;              /* Architecture pointer size */
 280         uint8_t alignment;              /* LTT data alignment */
 281         uint64_t start_time_sec;        /* NTP-corrected start time */
 282         uint64_t start_time_usec;
 283         uint64_t start_freq;            /*
 284                                          * Frequency at trace start,
 285                                          * used all along the trace.
 286                                          */
 287         uint32_t freq_scale;            /* Frequency scaling (divisor) */
 288         uint32_t lost_size;             /* Size unused at end of subbuffer */
 289         uint32_t buf_size;              /* Size of this subbuffer */
 290         uint32_t events_lost;           /*
 291                                          * Events lost in this subbuffer since
 292                                          * the beginning of the trace.
 293                                          * (may overflow)
 294                                          */
 295         uint32_t subbuf_corrupt;        /*
 296                                          * Corrupted (lost) subbuffers since
 297                                          * the begginig of the trace.
 298                                          * (may overflow)
 299                                          */
 300         uint8_t header_end[0];          /* End of header */
 301 };
 302
 303 /**
 304  * ltt_subbuffer_header_size - called on buffer-switch to a new sub-buffer
 305  *
 306  * Return header size without padding after the structure. Don't use packed
 307  * structure because gcc generates inefficient code on some architectures
 308  * (powerpc, mips..)
 309  */
 310 static inline size_t ltt_subbuffer_header_size(void)
 311 {
 312         return offsetof(struct ltt_subbuffer_header, header_end);
 313 }
 314
 315 /*
 316  * ltt_get_header_size
 317  *
 318  * Calculate alignment offset to 32-bits. This is the alignment offset of the
 319  * event header.
 320  *
 321  * Important note :
 322  * The event header must be 32-bits. The total offset calculated here :
 323  *
 324  * Alignment of header struct on 32 bits (min arch size, header size)
 325  * + sizeof(header struct)  (32-bits)
 326  * + (opt) u16 (ext. event id)
 327  * + (opt) u16 (event_size) (if event_size == 0xFFFFUL, has ext. event size)
 328  * + (opt) u32 (ext. event size)
 329  * + (opt) u64 full TSC (aligned on min(64-bits, arch size))
 330  *
 331  * The payload must itself determine its own alignment from the biggest type it
 332  * contains.
 333  * */
 334 static inline unsigned char ltt_get_header_size(
 335                 struct ltt_channel_struct *channel,
 336                 size_t offset,
 337                 size_t data_size,
 338                 size_t *before_hdr_pad,
 339                 unsigned int rflags)
 340 {
 341         size_t orig_offset = offset;
 342         size_t padding;
 343
 344         BUILD_BUG_ON(sizeof(struct ltt_event_header) != sizeof(u32));
 345
 346         padding = ltt_align(offset, sizeof(struct ltt_event_header));
 347         offset += padding;
 348         offset += sizeof(struct ltt_event_header);
 349
 350         switch (rflags) {
 351         case LTT_RFLAG_ID_SIZE_TSC:
 352                 offset += sizeof(u16) + sizeof(u16);
 353                 if (data_size >= 0xFFFFU)
 354                         offset += sizeof(u32);
 355                 offset += ltt_align(offset, sizeof(u64));
 356                 offset += sizeof(u64);
 357                 break;
 358         case LTT_RFLAG_ID_SIZE:
 359                 offset += sizeof(u16) + sizeof(u16);
 360                 if (data_size >= 0xFFFFU)
 361                         offset += sizeof(u32);
 362                 break;
 363         case LTT_RFLAG_ID:
 364                 offset += sizeof(u16);
 365                 break;
 366         }
 367
 368         *before_hdr_pad = padding;
 369         return offset - orig_offset;
 370 }
 371
 372 /*
 373  * ltt_write_event_header
 374  *
 375  * Writes the event header to the offset (already aligned on 32-bits).
 376  *
 377  * @trace : trace to write to.
 378  * @channel : pointer to the channel structure..
 379  * @buf : buffer to write to.
 380  * @buf_offset : buffer offset to write to (aligned on 32 bits).
 381  * @eID : event ID
 382  * @event_size : size of the event, excluding the event header.
 383  * @tsc : time stamp counter.
 384  * @rflags : reservation flags.
 385  *
 386  * returns : offset where the event data must be written.
 387  */
 388 static inline size_t ltt_write_event_header(struct ltt_trace_struct *trace,
 389                 struct ltt_channel_struct *channel,
 390                 struct rchan_buf *buf, long buf_offset,
 391                 u16 eID, size_t event_size,
 392                 u64 tsc, unsigned int rflags)
 393 {
 394         struct ltt_event_header header;
 395         size_t small_size;
 396
 397         switch (rflags) {
 398         case LTT_RFLAG_ID_SIZE_TSC:
 399                 header.id_time = 29 << LTT_TSC_BITS;
 400                 break;
 401         case LTT_RFLAG_ID_SIZE:
 402                 header.id_time = 30 << LTT_TSC_BITS;
 403                 break;
 404         case LTT_RFLAG_ID:
 405                 header.id_time = 31 << LTT_TSC_BITS;
 406                 break;
 407         default:
 408                 header.id_time = eID << LTT_TSC_BITS;
 409                 break;
 410         }
 411         header.id_time |= (u32)tsc & LTT_TSC_MASK;
 412         ltt_relay_write(buf, buf_offset, &header, sizeof(header));
 413         buf_offset += sizeof(header);
 414
 415         switch (rflags) {
 416         case LTT_RFLAG_ID_SIZE_TSC:
 417                 small_size = min_t(size_t, event_size, 0xFFFFU);
 418                 ltt_relay_write(buf, buf_offset,
 419                         (u16[]){ (u16)eID }, sizeof(u16));
 420                 buf_offset += sizeof(u16);
 421                 ltt_relay_write(buf, buf_offset,
 422                         (u16[]){ (u16)small_size }, sizeof(u16));
 423                 buf_offset += sizeof(u16);
 424                 if (small_size == 0xFFFFU) {
 425                         ltt_relay_write(buf, buf_offset,
 426                                 (u32[]){ (u32)event_size }, sizeof(u32));
 427                         buf_offset += sizeof(u32);
 428                 }
 429                 buf_offset += ltt_align(buf_offset, sizeof(u64));
 430                 ltt_relay_write(buf, buf_offset,
 431                         (u64[]){ (u64)tsc }, sizeof(u64));
 432                 buf_offset += sizeof(u64);
 433                 break;
 434         case LTT_RFLAG_ID_SIZE:
 435                 small_size = min_t(size_t, event_size, 0xFFFFU);
 436                 ltt_relay_write(buf, buf_offset,
 437                         (u16[]){ (u16)eID }, sizeof(u16));
 438                 buf_offset += sizeof(u16);
 439                 ltt_relay_write(buf, buf_offset,
 440                         (u16[]){ (u16)small_size }, sizeof(u16));
 441                 buf_offset += sizeof(u16);
 442                 if (small_size == 0xFFFFU) {
 443                         ltt_relay_write(buf, buf_offset,
 444                                 (u32[]){ (u32)event_size }, sizeof(u32));
 445                         buf_offset += sizeof(u32);
 446                 }
 447                 break;
 448         case LTT_RFLAG_ID:
 449                 ltt_relay_write(buf, buf_offset,
 450                         (u16[]){ (u16)eID }, sizeof(u16));
 451                 buf_offset += sizeof(u16);
 452                 break;
 453         default:
 454                 break;
 455         }
 456
 457         return buf_offset;
 458 }
 459
 460 /* Lockless LTTng */
 461
 462 /* Buffer offset macros */
 463
 464 /*
 465  * BUFFER_TRUNC zeroes the subbuffer offset and the subbuffer number parts of
 466  * the offset, which leaves only the buffer number.
 467  */
 468 #define BUFFER_TRUNC(offset, chan) \
 469         ((offset) & (~((chan)->alloc_size-1)))
 470 #define BUFFER_OFFSET(offset, chan) ((offset) & ((chan)->alloc_size - 1))
 471 #define SUBBUF_OFFSET(offset, chan) ((offset) & ((chan)->subbuf_size - 1))
 472 #define SUBBUF_ALIGN(offset, chan) \
 473         (((offset) + (chan)->subbuf_size) & (~((chan)->subbuf_size - 1)))
 474 #define SUBBUF_TRUNC(offset, chan) \
 475         ((offset) & (~((chan)->subbuf_size - 1)))
 476 #define SUBBUF_INDEX(offset, chan) \
 477         (BUFFER_OFFSET((offset), chan) >> (chan)->subbuf_size_order)
 478
 479 /*
 480  * ltt_reserve_slot
 481  *
 482  * Atomic slot reservation in a LTTng buffer. It will take care of
 483  * sub-buffer switching.
 484  *
 485  * Parameters:
 486  *
 487  * @trace : the trace structure to log to.
 488  * @channel : the chanel to reserve space into.
 489  * @transport_data : specific transport data.
 490  * @data_size : size of the variable length data to log.
 491  * @slot_size : pointer to total size of the slot (out)
 492  * @buf_offset : pointer to reserve offset (out)
 493  * @tsc : pointer to the tsc at the slot reservation (out)
 494  * @rflags : reservation flags (header specificity)
 495  * @cpu : cpu id
 496  *
 497  * Return : -ENOSPC if not enough space, else 0.
 498  */
 499 static inline int ltt_reserve_slot(
 500                 struct ltt_trace_struct *trace,
 501                 struct ltt_channel_struct *channel,
 502                 void **transport_data,
 503                 size_t data_size,
 504                 size_t *slot_size,
 505                 long *buf_offset,
 506                 u64 *tsc,
 507                 unsigned int *rflags,
 508                 int largest_align,
 509                 int cpu)
 510 {
 511         return trace->ops->reserve_slot(trace, channel, transport_data,
 512                         data_size, slot_size, buf_offset, tsc, rflags,
 513                         largest_align, cpu);
 514 }
 515
 516
 517 /*
 518  * ltt_commit_slot
 519  *
 520  * Atomic unordered slot commit. Increments the commit count in the
 521  * specified sub-buffer, and delivers it if necessary.
 522  *
 523  * Parameters:
 524  *
 525  * @channel : the chanel to reserve space into.
 526  * @transport_data : specific transport data.
 527  * @buf_offset : offset of beginning of reserved slot
 528  * @slot_size : size of the reserved slot.
 529  */
 530 static inline void ltt_commit_slot(
 531                 struct ltt_channel_struct *channel,
 532                 void **transport_data,
 533                 long buf_offset,
 534                 size_t slot_size)
 535 {
 536         struct ltt_trace_struct *trace = channel->trace;
 537
 538         trace->ops->commit_slot(channel, transport_data, buf_offset, slot_size);
 539 }
 540
 541 /*
 542  * Control channels :
 543  * control/metadata
 544  * control/interrupts
 545  * control/...
 546  *
 547  * cpu channel :
 548  * cpu
 549  */
 550 #define LTT_RELAY_ROOT          "ltt"
 551 #define LTT_RELAY_LOCKED_ROOT   "ltt-locked"
 552
 553 #define LTT_METADATA_CHANNEL            "metadata_state"
 554 #define LTT_FD_STATE_CHANNEL            "fd_state"
 555 #define LTT_GLOBAL_STATE_CHANNEL        "global_state"
 556 #define LTT_IRQ_STATE_CHANNEL           "irq_state"
 557 #define LTT_MODULE_STATE_CHANNEL        "module_state"
 558 #define LTT_NETIF_STATE_CHANNEL         "netif_state"
 559 #define LTT_SOFTIRQ_STATE_CHANNEL       "softirq_state"
 560 #define LTT_SWAP_STATE_CHANNEL          "swap_state"
 561 #define LTT_SYSCALL_STATE_CHANNEL       "syscall_state"
 562 #define LTT_TASK_STATE_CHANNEL          "task_state"
 563 #define LTT_VM_STATE_CHANNEL            "vm_state"
 564 #define LTT_FS_CHANNEL                  "fs"
 565 #define LTT_INPUT_CHANNEL               "input"
 566 #define LTT_IPC_CHANNEL                 "ipc"
 567 #define LTT_KERNEL_CHANNEL              "kernel"
 568 #define LTT_MM_CHANNEL                  "mm"
 569 #define LTT_RCU_CHANNEL                 "rcu"
 570
 571 #define LTT_FLIGHT_PREFIX       "flight-"
 572
 573 /* Tracer properties */
 574 #define LTT_DEFAULT_SUBBUF_SIZE_LOW     65536
 575 #define LTT_DEFAULT_N_SUBBUFS_LOW       2
 576 #define LTT_DEFAULT_SUBBUF_SIZE_MED     262144
 577 #define LTT_DEFAULT_N_SUBBUFS_MED       2
 578 #define LTT_DEFAULT_SUBBUF_SIZE_HIGH    1048576
 579 #define LTT_DEFAULT_N_SUBBUFS_HIGH      2
 580 #define LTT_TRACER_MAGIC_NUMBER         0x00D6B7ED
 581 #define LTT_TRACER_VERSION_MAJOR        2
 582 #define LTT_TRACER_VERSION_MINOR        3
 583
 584 /*
 585  * Size reserved for high priority events (interrupts, NMI, BH) at the end of a
 586  * nearly full buffer. User space won't use this last amount of space when in
 587  * blocking mode. This space also includes the event header that would be
 588  * written by this user space event.
 589  */
 590 #define LTT_RESERVE_CRITICAL            4096
 591
 592 /* Register and unregister function pointers */
 593
 594 enum ltt_module_function {
 595         LTT_FUNCTION_RUN_FILTER,
 596         LTT_FUNCTION_FILTER_CONTROL,
 597         LTT_FUNCTION_STATEDUMP
 598 };
 599
 600 extern int ltt_module_register(enum ltt_module_function name, void *function,
 601                 struct module *owner);
 602 extern void ltt_module_unregister(enum ltt_module_function name);
 603
 604 void ltt_transport_register(struct ltt_transport *transport);
 605 void ltt_transport_unregister(struct ltt_transport *transport);
 606
 607 /* Exported control function */
 608
 609 enum ltt_control_msg {
 610         LTT_CONTROL_START,
 611         LTT_CONTROL_STOP,
 612         LTT_CONTROL_CREATE_TRACE,
 613         LTT_CONTROL_DESTROY_TRACE
 614 };
 615
 616 union ltt_control_args {
 617         struct {
 618                 enum trace_mode mode;
 619                 unsigned int subbuf_size_low;
 620                 unsigned int n_subbufs_low;
 621                 unsigned int subbuf_size_med;
 622                 unsigned int n_subbufs_med;
 623                 unsigned int subbuf_size_high;
 624                 unsigned int n_subbufs_high;
 625         } new_trace;
 626 };
 627
 628 int _ltt_trace_setup(const char *trace_name);
 629 int ltt_trace_setup(const char *trace_name);
 630 struct ltt_trace_struct *_ltt_trace_find_setup(const char *trace_name);
 631 int ltt_trace_set_type(const char *trace_name, const char *trace_type);
 632 int ltt_trace_set_channel_subbufsize(const char *trace_name,
 633                 const char *channel_name, unsigned int size);
 634 int ltt_trace_set_channel_subbufcount(const char *trace_name,
 635                 const char *channel_name, unsigned int cnt);
 636 int ltt_trace_set_channel_enable(const char *trace_name,
 637                 const char *channel_name, unsigned int enable);
 638 int ltt_trace_set_channel_overwrite(const char *trace_name,
 639                 const char *channel_name, unsigned int overwrite);
 640 int ltt_trace_alloc(const char *trace_name);
 641 int ltt_trace_destroy(const char *trace_name);
 642 int ltt_trace_start(const char *trace_name);
 643 int ltt_trace_stop(const char *trace_name);
 644
 645 extern int ltt_control(enum ltt_control_msg msg, const char *trace_name,
 646                 const char *trace_type, union ltt_control_args args);
 647
 648 enum ltt_filter_control_msg {
 649         LTT_FILTER_DEFAULT_ACCEPT,
 650         LTT_FILTER_DEFAULT_REJECT
 651 };
 652
 653 extern int ltt_filter_control(enum ltt_filter_control_msg msg,
 654                 const char *trace_name);
 655
 656 extern struct dentry *get_filter_root(void);
 657
 658 void ltt_write_trace_header(struct ltt_trace_struct *trace,
 659                 struct ltt_subbuffer_header *header);
 660 extern void ltt_buffer_destroy(struct ltt_channel_struct *ltt_chan);
 661
 662 void ltt_core_register(int (*function)(u8, void *));
 663
 664 void ltt_core_unregister(void);
 665
 666 void ltt_release_trace(struct kref *kref);
 667 void ltt_release_transport(struct kref *kref);
 668
 669 extern int ltt_probe_register(struct ltt_available_probe *pdata);
 670 extern int ltt_probe_unregister(struct ltt_available_probe *pdata);
 671 extern int ltt_marker_connect(const char *channel, const char *mname,
 672                 const char *pname);
 673 extern int ltt_marker_disconnect(const char *channel, const char *mname,
 674                 const char *pname);
 675 extern void ltt_dump_marker_state(struct ltt_trace_struct *trace);
 676
 677 void ltt_lock_traces(void);
 678 void ltt_unlock_traces(void);
 679
 680 extern void ltt_dump_softirq_vec(void *call_data);
 681
 682 #ifdef CONFIG_HAVE_LTT_DUMP_TABLES
 683 extern void ltt_dump_sys_call_table(void *call_data);
 684 extern void ltt_dump_idt_table(void *call_data);
 685 #else
 686 static inline void ltt_dump_sys_call_table(void *call_data)
 687 {
 688 }
 689
 690 static inline void ltt_dump_idt_table(void *call_data)
 691 {
 692 }
 693 #endif
 694
 695 #ifdef CONFIG_LTT_KPROBES
 696 extern void ltt_dump_kprobes_table(void *call_data);
 697 #else
 698 static inline void ltt_dump_kprobes_table(void *call_data)
 699 {
 700 }
 701 #endif
 702
 703 /* Relay IOCTL */
 704
 705 /* Get the next sub buffer that can be read. */
 706 #define RELAY_GET_SUBBUF                _IOR(0xF5, 0x00, __u32)
 707 /* Release the oldest reserved (by "get") sub buffer. */
 708 #define RELAY_PUT_SUBBUF                _IOW(0xF5, 0x01, __u32)
 709 /* returns the number of sub buffers in the per cpu channel. */
 710 #define RELAY_GET_N_SUBBUFS             _IOR(0xF5, 0x02, __u32)
 711 /* returns the size of the sub buffers. */
 712 #define RELAY_GET_SUBBUF_SIZE           _IOR(0xF5, 0x03, __u32)
 713
 714 #endif /* CONFIG_LTT */
 715
 716 #endif /* _LTT_TRACER_H */