ltt-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  * Dual LGPL v2.1/GPL v2 license.
   7  */
   8
   9 #ifndef _LTT_TRACER_H
  10 #define _LTT_TRACER_H
  11
  12 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  13 /* Align data on its natural alignment */
  14 #define RING_BUFFER_ALIGN
  15 #endif
  16
  17 #include <linux/ringbuffer/config.h>
  18
  19 #include <stdarg.h>
  20 #include <linux/types.h>
  21 #include <linux/limits.h>
  22 #include <linux/list.h>
  23 #include <linux/cache.h>
  24 #include <linux/kernel.h>
  25 #include <linux/timex.h>
  26 #include <linux/wait.h>
  27 #include <linux/marker.h>
  28 #include <linux/trace-clock.h>
  29 #include <asm/atomic.h>
  30 #include <asm/local.h>
  31
  32 #include "ltt-tracer-core.h"
  33 #include "ltt-channels.h"
  34
  35 /* Number of bytes to log with a read/write event */
  36 #define LTT_LOG_RW_SIZE                 32L
  37
  38 struct ltt_active_marker;
  39
  40 /* Maximum number of callbacks per marker */
  41 #define LTT_NR_CALLBACKS        10
  42
  43 struct ltt_serialize_closure {
  44         ltt_serialize_cb *callbacks;
  45         long cb_args[LTT_NR_CALLBACKS];
  46         unsigned int cb_idx;
  47 };
  48
  49 size_t ltt_serialize_data(struct ltt_chanbuf *buf, size_t buf_offset,
  50                           struct ltt_serialize_closure *closure,
  51                           void *serialize_private, unsigned int stack_pos_ctx,
  52                           int *largest_align, const char *fmt, va_list *args);
  53
  54 struct ltt_available_probe {
  55         const char *name;               /* probe name */
  56         const char *format;
  57         marker_probe_func *probe_func;
  58         ltt_serialize_cb callbacks[LTT_NR_CALLBACKS];
  59         struct list_head node;          /* registered probes list */
  60 };
  61
  62 enum ltt_channels {
  63         LTT_CHANNEL_METADATA,
  64         LTT_CHANNEL_FD_STATE,
  65         LTT_CHANNEL_GLOBAL_STATE,
  66         LTT_CHANNEL_IRQ_STATE,
  67         LTT_CHANNEL_MODULE_STATE,
  68         LTT_CHANNEL_NETIF_STATE,
  69         LTT_CHANNEL_SOFTIRQ_STATE,
  70         LTT_CHANNEL_SWAP_STATE,
  71         LTT_CHANNEL_SYSCALL_STATE,
  72         LTT_CHANNEL_TASK_STATE,
  73         LTT_CHANNEL_VM_STATE,
  74         LTT_CHANNEL_FS,
  75         LTT_CHANNEL_INPUT,
  76         LTT_CHANNEL_IPC,
  77         LTT_CHANNEL_KERNEL,
  78         LTT_CHANNEL_MM,
  79         LTT_CHANNEL_RCU,
  80         LTT_CHANNEL_DEFAULT,
  81 };
  82
  83 struct ltt_active_marker {
  84         struct list_head node;          /* active markers list */
  85         const char *channel;
  86         const char *name;
  87         const char *format;
  88         struct ltt_available_probe *probe;
  89 };
  90
  91 extern void ltt_vtrace(const struct marker *mdata, void *probe_data,
  92                        void *call_data, const char *fmt, va_list *args);
  93 extern void ltt_trace(const struct marker *mdata, void *probe_data,
  94                       void *call_data, const char *fmt, ...);
  95
  96 size_t ltt_serialize_printf(struct ltt_chanbuf *buf, unsigned long buf_offset,
  97                             size_t *msg_size, char *output, size_t outlen,
  98                             const char *fmt);
  99
 100 /*
 101  * Unique ID assigned to each registered probe.
 102  */
 103 enum marker_id {
 104         MARKER_ID_SET_MARKER_ID = 0,    /* Static IDs available (range 0-7) */
 105         MARKER_ID_SET_MARKER_FORMAT,
 106         MARKER_ID_COMPACT,              /* Compact IDs (range: 8-127)       */
 107         MARKER_ID_DYNAMIC,              /* Dynamic IDs (range: 128-65535)   */
 108 };
 109
 110 /* static ids 0-1 reserved for internal use. */
 111 #define MARKER_CORE_IDS         2
 112 static __inline__ enum marker_id marker_id_type(uint16_t id)
 113 {
 114         if (id < MARKER_CORE_IDS)
 115                 return (enum marker_id)id;
 116         else
 117                 return MARKER_ID_DYNAMIC;
 118 }
 119
 120 struct user_dbg_data {
 121         unsigned long avail_size;
 122         unsigned long write;
 123         unsigned long read;
 124 };
 125
 126 enum trace_mode { LTT_TRACE_NORMAL, LTT_TRACE_FLIGHT, LTT_TRACE_HYBRID };
 127
 128 #define CHANNEL_FLAG_ENABLE     (1U<<0)
 129 #define CHANNEL_FLAG_OVERWRITE  (1U<<1)
 130
 131 #if 0
 132 /* Per-trace information - each trace/flight recorder represented by one */
 133 struct ltt_trace {
 134         /* First 32 bytes cache-hot cacheline */
 135         struct list_head list;
 136         struct ltt_chan **channels;
 137         unsigned int nr_channels;
 138         int active;
 139         /* Second 32 bytes cache-hot cacheline */
 140         struct ltt_trace_ops *ops;
 141         u32 freq_scale;
 142         u64 start_freq;
 143         u64 start_tsc;
 144         unsigned long long start_monotonic;
 145         struct timeval          start_time;
 146         struct ltt_channel_setting *settings;
 147         struct {
 148                 struct dentry                   *trace_root;
 149                 struct dentry                   *ascii_root;
 150         } dentry;
 151         struct kref kref; /* Each channel has a kref of the trace struct */
 152         struct ltt_transport *transport;
 153         struct kref ltt_transport_kref;
 154         wait_queue_head_t kref_wq; /* Place for ltt_trace_destroy to sleep */
 155         char trace_name[NAME_MAX];
 156 } ____cacheline_aligned;
 157 #endif //0
 158
 159 /*
 160  * Hardcoded event headers
 161  *
 162  * event header for a trace with active heartbeat : 27 bits timestamps
 163  *
 164  * headers are 32-bits aligned. In order to insure such alignment, a dynamic per
 165  * trace alignment value must be done.
 166  *
 167  * Remember that the C compiler does align each member on the boundary
 168  * equivalent to their own size.
 169  *
 170  * As relay subbuffers are aligned on pages, we are sure that they are 4 and 8
 171  * bytes aligned, so the buffer header and trace header are aligned.
 172  *
 173  * Event headers are aligned depending on the trace alignment option.
 174  *
 175  * Note using C structure bitfields for cross-endianness and portability
 176  * concerns.
 177  */
 178
 179 #define LTT_RESERVED_EVENTS     3
 180 #define LTT_EVENT_BITS          5
 181 #define LTT_FREE_EVENTS         ((1 << LTT_EVENT_BITS) - LTT_RESERVED_EVENTS)
 182 #define LTT_TSC_BITS            27
 183 #define LTT_TSC_MASK            ((1 << LTT_TSC_BITS) - 1)
 184
 185 struct event_header {
 186         u32 id_time;            /* 5 bits event id (MSB); 27 bits time (LSB) */
 187 };
 188
 189 /* Reservation flags */
 190 #define LTT_RFLAG_ID                    (1 << 0)
 191 #define LTT_RFLAG_ID_SIZE               (1 << 1)
 192 #define LTT_RFLAG_ID_SIZE_TSC           (1 << 2)
 193
 194 #define LTT_MAX_SMALL_SIZE              0xFFFFU
 195
 196 /*
 197  * We use asm/timex.h : cpu_khz/HZ variable in here : we might have to deal
 198  * specifically with CPU frequency scaling someday, so using an interpolation
 199  * between the start and end of buffer values is not flexible enough. Using an
 200  * immediate frequency value permits to calculate directly the times for parts
 201  * of a buffer that would be before a frequency change.
 202  *
 203  * Keep the natural field alignment for _each field_ within this structure if
 204  * you ever add/remove a field from this header. Packed attribute is not used
 205  * because gcc generates poor code on at least powerpc and mips. Don't ever
 206  * let gcc add padding between the structure elements.
 207  */
 208 struct subbuffer_header {
 209         uint64_t cycle_count_begin;     /* Cycle count at subbuffer start */
 210         uint64_t cycle_count_end;       /* Cycle count at subbuffer end */
 211         uint32_t magic_number;          /*
 212                                          * Trace magic number.
 213                                          * contains endianness information.
 214                                          */
 215         uint8_t major_version;
 216         uint8_t minor_version;
 217         uint8_t arch_size;              /* Architecture pointer size */
 218         uint8_t alignment;              /* LTT data alignment */
 219         uint64_t start_time_sec;        /* NTP-corrected start time */
 220         uint64_t start_time_usec;
 221         uint64_t start_freq;            /*
 222                                          * Frequency at trace start,
 223                                          * used all along the trace.
 224                                          */
 225         uint32_t freq_scale;            /* Frequency scaling (divisor) */
 226         uint32_t data_size;             /* Size of data in subbuffer */
 227         uint32_t sb_size;               /* Subbuffer size (include padding) */
 228         uint32_t events_lost;           /*
 229                                          * Events lost in this subbuffer since
 230                                          * the beginning of the trace.
 231                                          * (may overflow)
 232                                          */
 233         uint32_t subbuf_corrupt;        /*
 234                                          * Corrupted (lost) subbuffers since
 235                                          * the begginig of the trace.
 236                                          * (may overflow)
 237                                          */
 238         uint8_t header_end[0];          /* End of header */
 239 };
 240
 241 static inline notrace u64 lib_ring_buffer_clock_read(struct channel *chan)
 242 {
 243         return trace_clock_read64();
 244 }
 245
 246 /*
 247  * record_header_size - Calculate the header size and padding necessary.
 248  * @config: ring buffer instance configuration
 249  * @chan: channel
 250  * @offset: offset in the write buffer
 251  * @data_size: size of the payload
 252  * @pre_header_padding: padding to add before the header (output)
 253  * @rflags: reservation flags
 254  * @ctx: reservation context
 255  *
 256  * Returns the event header size (including padding).
 257  *
 258  * Important note :
 259  * The event header must be 32-bits. The total offset calculated here :
 260  *
 261  * Alignment of header struct on 32 bits (min arch size, header size)
 262  * + sizeof(header struct)  (32-bits)
 263  * + (opt) u16 (ext. event id)
 264  * + (opt) u16 (event_size)
 265  *             (if event_size == LTT_MAX_SMALL_SIZE, has ext. event size)
 266  * + (opt) u32 (ext. event size)
 267  * + (opt) u64 full TSC (aligned on min(64-bits, arch size))
 268  *
 269  * The payload must itself determine its own alignment from the biggest type it
 270  * contains.
 271  */
 272 static __inline__
 273 unsigned char record_header_size(const struct lib_ring_buffer_config *config,
 274                                  struct channel *chan, size_t offset,
 275                                  size_t data_size, size_t *pre_header_padding,
 276                                  unsigned int rflags,
 277                                  struct lib_ring_buffer_ctx *ctx)
 278 {
 279         size_t orig_offset = offset;
 280         size_t padding;
 281
 282         BUILD_BUG_ON(sizeof(struct event_header) != sizeof(u32));
 283
 284         padding = lib_ring_buffer_align(config, offset,
 285                                         sizeof(struct event_header));
 286         offset += padding;
 287         offset += sizeof(struct event_header);
 288
 289         if (unlikely(rflags)) {
 290                 switch (rflags) {
 291                 case LTT_RFLAG_ID_SIZE_TSC:
 292                         offset += sizeof(u16) + sizeof(u16);
 293                         if (data_size >= LTT_MAX_SMALL_SIZE)
 294                                 offset += sizeof(u32);
 295                         offset += ltt_align(offset, sizeof(u64));
 296                         offset += sizeof(u64);
 297                         break;
 298                 case LTT_RFLAG_ID_SIZE:
 299                         offset += sizeof(u16) + sizeof(u16);
 300                         if (data_size >= LTT_MAX_SMALL_SIZE)
 301                                 offset += sizeof(u32);
 302                         break;
 303                 case LTT_RFLAG_ID:
 304                         offset += sizeof(u16);
 305                         break;
 306                 }
 307         }
 308
 309         *pre_header_padding = padding;
 310         return offset - orig_offset;
 311 }
 312
 313 #include <linux/ringbuffer/api.h>
 314
 315 extern
 316 size_t ltt_write_event_header_slow(struct ltt_chanbuf_alloc *bufa,
 317                                    struct ltt_chan_alloc *chana,
 318                                    long buf_offset, u16 eID, u32 event_size,
 319                                    u64 tsc, unsigned int rflags);
 320
 321 /*
 322  * ltt_write_event_header
 323  *
 324  * Writes the event header to the offset (already aligned on 32-bits).
 325  *
 326  * @config: ring buffer instance configuration
 327  * @ctx: reservation context
 328  * @eID : event ID
 329  * @event_size : size of the event, excluding the event header.
 330  */
 331 static __inline__
 332 void ltt_write_event_header(const struct lib_ring_buffer_config *config,
 333                             struct lib_ring_buffer_ctx *ctx,
 334                             u16 eID, u32 event_size)
 335 {
 336         struct event_header header;
 337
 338         if (unlikely(ctx->rflags))
 339                 goto slow_path;
 340
 341         header.id_time = eID << LTT_TSC_BITS;
 342         header.id_time |= (u32)ctx->tsc & LTT_TSC_MASK;
 343         lib_ring_buffer_write(config, ctx, &header, sizeof(header));
 344
 345 slow_path:
 346         ltt_write_event_header_slow(config, ctx, eID, event_size);
 347 }
 348
 349 #if 0
 350 /*
 351  * ltt_read_event_header
 352  * buf_offset must aligned on 32 bits
 353  */
 354 static __inline__
 355 size_t ltt_read_event_header(struct ltt_chanbuf_alloc *bufa, long buf_offset,
 356                              u64 *tsc, u32 *event_size, u16 *eID,
 357                              unsigned int *rflags)
 358 {
 359         struct ltt_event_header header;
 360         u16 small_size;
 361
 362         ltt_relay_read(bufa, buf_offset, &header, sizeof(header));
 363         buf_offset += sizeof(header);
 364
 365         *event_size = INT_MAX;
 366         *eID = header.id_time >> LTT_TSC_BITS;
 367         *tsc = header.id_time & LTT_TSC_MASK;
 368
 369         switch (*eID) {
 370         case 29:
 371                 *rflags = LTT_RFLAG_ID_SIZE_TSC;
 372                 ltt_relay_read(bufa, buf_offset, eID, sizeof(u16));
 373                 buf_offset += sizeof(u16);
 374                 ltt_relay_read(bufa, buf_offset, &small_size, sizeof(u16));
 375                 buf_offset += sizeof(u16);
 376                 if (small_size == LTT_MAX_SMALL_SIZE) {
 377                         ltt_relay_read(bufa, buf_offset, event_size,
 378                                         sizeof(u32));
 379                         buf_offset += sizeof(u32);
 380                 } else
 381                         *event_size = small_size;
 382                 buf_offset += ltt_align(buf_offset, sizeof(u64));
 383                 ltt_relay_read(bufa, buf_offset, tsc, sizeof(u64));
 384                 buf_offset += sizeof(u64);
 385                 break;
 386         case 30:
 387                 *rflags = LTT_RFLAG_ID_SIZE;
 388                 ltt_relay_read(bufa, buf_offset, eID, sizeof(u16));
 389                 buf_offset += sizeof(u16);
 390                 ltt_relay_read(bufa, buf_offset, &small_size, sizeof(u16));
 391                 buf_offset += sizeof(u16);
 392                 if (small_size == LTT_MAX_SMALL_SIZE) {
 393                         ltt_relay_read(bufa, buf_offset, event_size,
 394                                         sizeof(u32));
 395                         buf_offset += sizeof(u32);
 396                 } else
 397                         *event_size = small_size;
 398                 break;
 399         case 31:
 400                 *rflags = LTT_RFLAG_ID;
 401                 ltt_relay_read(bufa, buf_offset, eID, sizeof(u16));
 402                 buf_offset += sizeof(u16);
 403                 break;
 404         default:
 405                 *rflags = 0;
 406                 break;
 407         }
 408
 409         return buf_offset;
 410 }
 411 #endif //0
 412
 413 /*
 414  * Control channels :
 415  * control/metadata
 416  * control/interrupts
 417  * control/...
 418  *
 419  * cpu channel :
 420  * cpu
 421  */
 422 #define LTT_RELAY_ROOT                  "ltt"
 423
 424 #define LTT_METADATA_CHANNEL            "metadata_state"
 425 #define LTT_FD_STATE_CHANNEL            "fd_state"
 426 #define LTT_GLOBAL_STATE_CHANNEL        "global_state"
 427 #define LTT_IRQ_STATE_CHANNEL           "irq_state"
 428 #define LTT_MODULE_STATE_CHANNEL        "module_state"
 429 #define LTT_NETIF_STATE_CHANNEL         "netif_state"
 430 #define LTT_SOFTIRQ_STATE_CHANNEL       "softirq_state"
 431 #define LTT_SWAP_STATE_CHANNEL          "swap_state"
 432 #define LTT_SYSCALL_STATE_CHANNEL       "syscall_state"
 433 #define LTT_TASK_STATE_CHANNEL          "task_state"
 434 #define LTT_VM_STATE_CHANNEL            "vm_state"
 435 #define LTT_FS_CHANNEL                  "fs"
 436 #define LTT_INPUT_CHANNEL               "input"
 437 #define LTT_IPC_CHANNEL                 "ipc"
 438 #define LTT_KERNEL_CHANNEL              "kernel"
 439 #define LTT_MM_CHANNEL                  "mm"
 440 #define LTT_RCU_CHANNEL                 "rcu"
 441
 442 #define LTT_FLIGHT_PREFIX               "flight-"
 443
 444 #define LTT_ASCII                       "ascii"
 445
 446 /* Tracer properties */
 447 #define LTT_DEFAULT_SUBBUF_SIZE_LOW     65536
 448 #define LTT_DEFAULT_N_SUBBUFS_LOW       2
 449 #define LTT_DEFAULT_SUBBUF_SIZE_MED     262144
 450 #define LTT_DEFAULT_N_SUBBUFS_MED       2
 451 #define LTT_DEFAULT_SUBBUF_SIZE_HIGH    1048576
 452 #define LTT_DEFAULT_N_SUBBUFS_HIGH      2
 453 #define LTT_TRACER_MAGIC_NUMBER         0x00D6B7ED
 454 #define LTT_TRACER_VERSION_MAJOR        2
 455 #define LTT_TRACER_VERSION_MINOR        6
 456
 457 /**
 458  * ltt_write_trace_header - Write trace header
 459  * @priv: Private data (struct trace)
 460  * @header: Memory address where the information must be written to
 461  */
 462 static __inline__
 463 void ltt_write_trace_header(void *priv,
 464                             struct subbuffer_header *header)
 465 {
 466         struct ltt_trace *trace = priv;
 467
 468         header->magic_number = LTT_TRACER_MAGIC_NUMBER;
 469         header->major_version = LTT_TRACER_VERSION_MAJOR;
 470         header->minor_version = LTT_TRACER_VERSION_MINOR;
 471         header->arch_size = sizeof(void *);
 472         header->alignment = lib_ring_buffer_get_alignment();
 473         header->start_time_sec = trace->start_time.tv_sec;
 474         header->start_time_usec = trace->start_time.tv_usec;
 475         header->start_freq = trace->start_freq;
 476         header->freq_scale = trace->freq_scale;
 477 }
 478
 479 /*
 480  * Size reserved for high priority events (interrupts, NMI, BH) at the end of a
 481  * nearly full buffer. User space won't use this last amount of space when in
 482  * blocking mode. This space also includes the event header that would be
 483  * written by this user space event.
 484  */
 485 #define LTT_RESERVE_CRITICAL            4096
 486
 487 /* Register and unregister function pointers */
 488
 489 enum ltt_module_function {
 490         LTT_FUNCTION_RUN_FILTER,
 491         LTT_FUNCTION_FILTER_CONTROL,
 492         LTT_FUNCTION_STATEDUMP
 493 };
 494
 495 extern int ltt_module_register(enum ltt_module_function name, void *function,
 496                                struct module *owner);
 497 extern void ltt_module_unregister(enum ltt_module_function name);
 498
 499 /* Exported control function */
 500
 501 enum ltt_control_msg {
 502         LTT_CONTROL_START,
 503         LTT_CONTROL_STOP,
 504         LTT_CONTROL_CREATE_TRACE,
 505         LTT_CONTROL_DESTROY_TRACE
 506 };
 507
 508 union ltt_control_args {
 509         struct {
 510                 enum trace_mode mode;
 511                 unsigned int subbuf_size_low;
 512                 unsigned int n_subbufs_low;
 513                 unsigned int subbuf_size_med;
 514                 unsigned int n_subbufs_med;
 515                 unsigned int subbuf_size_high;
 516                 unsigned int n_subbufs_high;
 517         } new_trace;
 518 };
 519
 520 void ltt_core_register(int (*function)(u8, void *));
 521
 522 void ltt_core_unregister(void);
 523
 524 extern int ltt_probe_register(struct ltt_available_probe *pdata);
 525 extern int ltt_probe_unregister(struct ltt_available_probe *pdata);
 526 extern int ltt_marker_connect(const char *channel, const char *mname,
 527                               const char *pname);
 528 extern int ltt_marker_disconnect(const char *channel, const char *mname,
 529                                  const char *pname);
 530 extern void ltt_dump_marker_state(struct ltt_trace *trace);
 531
 532 extern
 533 void ltt_statedump_register_kprobes_dump(void (*callback)(void *call_data));
 534 extern
 535 void ltt_statedump_unregister_kprobes_dump(void (*callback)(void *call_data));
 536
 537 extern void ltt_dump_softirq_vec(void *call_data);
 538
 539 #ifdef CONFIG_HAVE_LTT_DUMP_TABLES
 540 extern void ltt_dump_sys_call_table(void *call_data);
 541 extern void ltt_dump_idt_table(void *call_data);
 542 #else
 543 static inline void ltt_dump_sys_call_table(void *call_data)
 544 {
 545 }
 546
 547 static inline void ltt_dump_idt_table(void *call_data)
 548 {
 549 }
 550 #endif
 551
 552 #endif /* _LTT_TRACER_H */