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 #include <stdarg.h>
  13 #include <linux/types.h>
  14 #include <linux/limits.h>
  15 #include <linux/list.h>
  16 #include <linux/cache.h>
  17 #include <linux/timex.h>
  18 #include <linux/wait.h>
  19 #include <linux/trace-clock.h>
  20 #include <asm/atomic.h>
  21 #include <asm/local.h>
  22
  23 #include "ltt-tracer-core.h"
  24 #include "ltt-events.h"
  25
  26 /* Number of bytes to log with a read/write event */
  27 #define LTT_LOG_RW_SIZE                 32L
  28
  29 /* Maximum number of callbacks per marker */
  30 #define LTT_NR_CALLBACKS        10
  31
  32 struct ltt_serialize_closure;
  33
  34 /* Serialization callback */
  35 typedef size_t (*ltt_serialize_cb)(struct lib_ring_buffer *buf,
  36                                    size_t buf_offset,
  37                                    struct ltt_serialize_closure *closure,
  38                                    void *serialize_private,
  39                                    unsigned int stack_pos_ctx,
  40                                    int *largest_align,
  41                                    const char *fmt, va_list *args);
  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 lib_ring_buffer *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 enum ltt_channels {
  55         LTT_CHANNEL_METADATA,
  56         LTT_CHANNEL_FD_STATE,
  57         LTT_CHANNEL_GLOBAL_STATE,
  58         LTT_CHANNEL_IRQ_STATE,
  59         LTT_CHANNEL_MODULE_STATE,
  60         LTT_CHANNEL_NETIF_STATE,
  61         LTT_CHANNEL_SOFTIRQ_STATE,
  62         LTT_CHANNEL_SWAP_STATE,
  63         LTT_CHANNEL_SYSCALL_STATE,
  64         LTT_CHANNEL_TASK_STATE,
  65         LTT_CHANNEL_VM_STATE,
  66         LTT_CHANNEL_FS,
  67         LTT_CHANNEL_INPUT,
  68         LTT_CHANNEL_IPC,
  69         LTT_CHANNEL_KERNEL,
  70         LTT_CHANNEL_MM,
  71         LTT_CHANNEL_RCU,
  72         LTT_CHANNEL_DEFAULT,
  73 };
  74
  75 #if 0
  76 size_t ltt_serialize_printf(struct lib_ring_buffer *buf, unsigned long buf_offset,
  77                             size_t *msg_size, char *output, size_t outlen,
  78                             const char *fmt);
  79
  80 /*
  81  * Unique ID assigned to each registered probe.
  82  */
  83 enum marker_id {
  84         MARKER_ID_SET_MARKER_ID = 0,    /* Static IDs available (range 0-7) */
  85         MARKER_ID_SET_MARKER_FORMAT,
  86         MARKER_ID_COMPACT,              /* Compact IDs (range: 8-127)       */
  87         MARKER_ID_DYNAMIC,              /* Dynamic IDs (range: 128-65535)   */
  88 };
  89
  90 /* static ids 0-1 reserved for internal use. */
  91 #define MARKER_CORE_IDS         2
  92 static __inline__ enum marker_id marker_id_type(uint16_t id)
  93 {
  94         if (id < MARKER_CORE_IDS)
  95                 return (enum marker_id)id;
  96         else
  97                 return MARKER_ID_DYNAMIC;
  98 }
  99
 100 struct user_dbg_data {
 101         unsigned long avail_size;
 102         unsigned long write;
 103         unsigned long read;
 104 };
 105
 106 enum trace_mode { LTT_TRACE_NORMAL, LTT_TRACE_FLIGHT, LTT_TRACE_HYBRID };
 107
 108 #define CHANNEL_FLAG_ENABLE     (1U<<0)
 109 #define CHANNEL_FLAG_OVERWRITE  (1U<<1)
 110 #endif //0
 111
 112 #if 0
 113 /* Per-trace information - each trace/flight recorder represented by one */
 114 struct ltt_trace {
 115         /* First 32 bytes cache-hot cacheline */
 116         struct list_head list;
 117         struct ltt_chan **channels;
 118         unsigned int nr_channels;
 119         int active;
 120         /* Second 32 bytes cache-hot cacheline */
 121         struct ltt_trace_ops *ops;
 122         u32 freq_scale;
 123         u64 start_freq;
 124         u64 start_tsc;
 125         unsigned long long start_monotonic;
 126         struct timeval          start_time;
 127         struct ltt_channel_setting *settings;
 128         struct {
 129                 struct dentry                   *trace_root;
 130                 struct dentry                   *ascii_root;
 131         } dentry;
 132         struct kref kref; /* Each channel has a kref of the trace struct */
 133         struct ltt_transport *transport;
 134         struct kref ltt_transport_kref;
 135         wait_queue_head_t kref_wq; /* Place for ltt_trace_destroy to sleep */
 136         char trace_name[NAME_MAX];
 137 } ____cacheline_aligned;
 138 #endif //0
 139
 140 /*
 141  * Hardcoded event headers
 142  *
 143  * event header for a trace with active heartbeat : 27 bits timestamps
 144  *
 145  * headers are 32-bits aligned. In order to insure such alignment, a dynamic per
 146  * trace alignment value must be done.
 147  *
 148  * Remember that the C compiler does align each member on the boundary
 149  * equivalent to their own size.
 150  *
 151  * As relay subbuffers are aligned on pages, we are sure that they are 4 and 8
 152  * bytes aligned, so the buffer header and trace header are aligned.
 153  *
 154  * Event headers are aligned depending on the trace alignment option.
 155  *
 156  * Note using C structure bitfields for cross-endianness and portability
 157  * concerns.
 158  */
 159
 160 #define LTT_RESERVED_EVENTS     3
 161 #define LTT_EVENT_BITS          5
 162 #define LTT_FREE_EVENTS         ((1 << LTT_EVENT_BITS) - LTT_RESERVED_EVENTS)
 163 #define LTT_TSC_BITS            27
 164 #define LTT_TSC_MASK            ((1 << LTT_TSC_BITS) - 1)
 165
 166 struct event_header {
 167         u32 id_time;            /* 5 bits event id (MSB); 27 bits time (LSB) */
 168 };
 169
 170 /* Reservation flags */
 171 #define LTT_RFLAG_ID                    (1 << 0)
 172 #define LTT_RFLAG_ID_SIZE               (1 << 1)
 173 #define LTT_RFLAG_ID_SIZE_TSC           (1 << 2)
 174
 175 #define LTT_MAX_SMALL_SIZE              0xFFFFU
 176
 177 /*
 178  * We use asm/timex.h : cpu_khz/HZ variable in here : we might have to deal
 179  * specifically with CPU frequency scaling someday, so using an interpolation
 180  * between the start and end of buffer values is not flexible enough. Using an
 181  * immediate frequency value permits to calculate directly the times for parts
 182  * of a buffer that would be before a frequency change.
 183  *
 184  * Keep the natural field alignment for _each field_ within this structure if
 185  * you ever add/remove a field from this header. Packed attribute is not used
 186  * because gcc generates poor code on at least powerpc and mips. Don't ever
 187  * let gcc add padding between the structure elements.
 188  */
 189 struct packet_header {
 190         uint32_t magic;                 /*
 191                                          * Trace magic number.
 192                                          * contains endianness information.
 193                                          */
 194         uint8_t trace_uuid[16];
 195         uint32_t stream_id;
 196         uint64_t timestamp_begin;       /* Cycle count at subbuffer start */
 197         uint64_t timestamp_end; /* Cycle count at subbuffer end */
 198         uint32_t content_size;          /* Size of data in subbuffer */
 199         uint32_t packet_size;           /* Subbuffer size (include padding) */
 200         uint32_t events_lost;           /*
 201                                          * Events lost in this subbuffer since
 202                                          * the beginning of the trace.
 203                                          * (may overflow)
 204                                          */
 205         /* TODO: move to metadata */
 206 #if 0
 207         uint8_t major_version;
 208         uint8_t minor_version;
 209         uint8_t arch_size;              /* Architecture pointer size */
 210         uint8_t alignment;              /* LTT data alignment */
 211         uint64_t start_time_sec;        /* NTP-corrected start time */
 212         uint64_t start_time_usec;
 213         uint64_t start_freq;            /*
 214                                          * Frequency at trace start,
 215                                          * used all along the trace.
 216                                          */
 217         uint32_t freq_scale;            /* Frequency scaling (divisor) */
 218 #endif //0
 219         uint8_t header_end[0];          /* End of header */
 220 };
 221
 222 static inline notrace u64 lib_ring_buffer_clock_read(struct channel *chan)
 223 {
 224         return trace_clock_read64();
 225 }
 226
 227 /*
 228  * record_header_size - Calculate the header size and padding necessary.
 229  * @config: ring buffer instance configuration
 230  * @chan: channel
 231  * @offset: offset in the write buffer
 232  * @data_size: size of the payload
 233  * @pre_header_padding: padding to add before the header (output)
 234  * @rflags: reservation flags
 235  * @ctx: reservation context
 236  *
 237  * Returns the event header size (including padding).
 238  *
 239  * Important note :
 240  * The event header must be 32-bits. The total offset calculated here :
 241  *
 242  * Alignment of header struct on 32 bits (min arch size, header size)
 243  * + sizeof(header struct)  (32-bits)
 244  * + (opt) u16 (ext. event id)
 245  * + (opt) u16 (event_size)
 246  *             (if event_size == LTT_MAX_SMALL_SIZE, has ext. event size)
 247  * + (opt) u32 (ext. event size)
 248  * + (opt) u64 full TSC (aligned on min(64-bits, arch size))
 249  *
 250  * The payload must itself determine its own alignment from the biggest type it
 251  * contains.
 252  */
 253 static __inline__
 254 unsigned char record_header_size(const struct lib_ring_buffer_config *config,
 255                                  struct channel *chan, size_t offset,
 256                                  size_t data_size, size_t *pre_header_padding,
 257                                  unsigned int rflags,
 258                                  struct lib_ring_buffer_ctx *ctx)
 259 {
 260         size_t orig_offset = offset;
 261         size_t padding;
 262
 263         BUILD_BUG_ON(sizeof(struct event_header) != sizeof(u32));
 264
 265         padding = lib_ring_buffer_align(offset,
 266                                         sizeof(struct event_header));
 267         offset += padding;
 268         offset += sizeof(struct event_header);
 269
 270         if (unlikely(rflags)) {
 271                 switch (rflags) {
 272                 case LTT_RFLAG_ID_SIZE_TSC:
 273                         offset += sizeof(u16) + sizeof(u16);
 274                         if (data_size >= LTT_MAX_SMALL_SIZE)
 275                                 offset += sizeof(u32);
 276                         offset += lib_ring_buffer_align(offset, sizeof(u64));
 277                         offset += sizeof(u64);
 278                         break;
 279                 case LTT_RFLAG_ID_SIZE:
 280                         offset += sizeof(u16) + sizeof(u16);
 281                         if (data_size >= LTT_MAX_SMALL_SIZE)
 282                                 offset += sizeof(u32);
 283                         break;
 284                 case LTT_RFLAG_ID:
 285                         offset += sizeof(u16);
 286                         break;
 287                 }
 288         }
 289
 290         *pre_header_padding = padding;
 291         return offset - orig_offset;
 292 }
 293
 294 #include <linux/ringbuffer/api.h>
 295
 296 extern
 297 void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config,
 298                                  struct lib_ring_buffer_ctx *ctx,
 299                                  u16 eID, u32 event_size);
 300
 301 /*
 302  * ltt_write_event_header
 303  *
 304  * Writes the event header to the offset (already aligned on 32-bits).
 305  *
 306  * @config: ring buffer instance configuration
 307  * @ctx: reservation context
 308  * @eID : event ID
 309  * @event_size : size of the event, excluding the event header.
 310  */
 311 static __inline__
 312 void ltt_write_event_header(const struct lib_ring_buffer_config *config,
 313                             struct lib_ring_buffer_ctx *ctx,
 314                             u16 eID, u32 event_size)
 315 {
 316         struct event_header header;
 317
 318         if (unlikely(ctx->rflags))
 319                 goto slow_path;
 320
 321         header.id_time = eID << LTT_TSC_BITS;
 322         header.id_time |= (u32)ctx->tsc & LTT_TSC_MASK;
 323         lib_ring_buffer_write(config, ctx, &header, sizeof(header));
 324
 325 slow_path:
 326         ltt_write_event_header_slow(config, ctx, eID, event_size);
 327 }
 328
 329 #if 0
 330 /*
 331  * ltt_read_event_header
 332  * buf_offset must aligned on 32 bits
 333  */
 334 static __inline__
 335 size_t ltt_read_event_header(struct ltt_chanbuf_alloc *bufa, long buf_offset,
 336                              u64 *tsc, u32 *event_size, u16 *eID,
 337                              unsigned int *rflags)
 338 {
 339         struct ltt_event_header header;
 340         u16 small_size;
 341
 342         ltt_relay_read(bufa, buf_offset, &header, sizeof(header));
 343         buf_offset += sizeof(header);
 344
 345         *event_size = INT_MAX;
 346         *eID = header.id_time >> LTT_TSC_BITS;
 347         *tsc = header.id_time & LTT_TSC_MASK;
 348
 349         switch (*eID) {
 350         case 29:
 351                 *rflags = LTT_RFLAG_ID_SIZE_TSC;
 352                 ltt_relay_read(bufa, buf_offset, eID, sizeof(u16));
 353                 buf_offset += sizeof(u16);
 354                 ltt_relay_read(bufa, buf_offset, &small_size, sizeof(u16));
 355                 buf_offset += sizeof(u16);
 356                 if (small_size == LTT_MAX_SMALL_SIZE) {
 357                         ltt_relay_read(bufa, buf_offset, event_size,
 358                                         sizeof(u32));
 359                         buf_offset += sizeof(u32);
 360                 } else
 361                         *event_size = small_size;
 362                 buf_offset += ltt_align(buf_offset, sizeof(u64));
 363                 ltt_relay_read(bufa, buf_offset, tsc, sizeof(u64));
 364                 buf_offset += sizeof(u64);
 365                 break;
 366         case 30:
 367                 *rflags = LTT_RFLAG_ID_SIZE;
 368                 ltt_relay_read(bufa, buf_offset, eID, sizeof(u16));
 369                 buf_offset += sizeof(u16);
 370                 ltt_relay_read(bufa, buf_offset, &small_size, sizeof(u16));
 371                 buf_offset += sizeof(u16);
 372                 if (small_size == LTT_MAX_SMALL_SIZE) {
 373                         ltt_relay_read(bufa, buf_offset, event_size,
 374                                         sizeof(u32));
 375                         buf_offset += sizeof(u32);
 376                 } else
 377                         *event_size = small_size;
 378                 break;
 379         case 31:
 380                 *rflags = LTT_RFLAG_ID;
 381                 ltt_relay_read(bufa, buf_offset, eID, sizeof(u16));
 382                 buf_offset += sizeof(u16);
 383                 break;
 384         default:
 385                 *rflags = 0;
 386                 break;
 387         }
 388
 389         return buf_offset;
 390 }
 391 #endif //0
 392
 393 /* Tracer properties */
 394 #define CTF_MAGIC_NUMBER                0xC1FC1FC1
 395 #define LTT_TRACER_VERSION_MAJOR        3
 396 #define LTT_TRACER_VERSION_MINOR        0
 397
 398 /**
 399  * ltt_write_trace_header - Write trace header
 400  * @priv: Private data (struct trace)
 401  * @header: Memory address where the information must be written to
 402  */
 403 static __inline__
 404 void write_trace_header(const struct lib_ring_buffer_config *config,
 405                         struct packet_header *header)
 406 {
 407         header->magic = CTF_MAGIC_NUMBER;
 408 #if 0
 409         /* TODO: move start time to metadata */
 410         header->major_version = LTT_TRACER_VERSION_MAJOR;
 411         header->minor_version = LTT_TRACER_VERSION_MINOR;
 412         header->arch_size = sizeof(void *);
 413         header->alignment = lib_ring_buffer_get_alignment(config);
 414         header->start_time_sec = ltt_chan->session->start_time.tv_sec;
 415         header->start_time_usec = ltt_chan->session->start_time.tv_usec;
 416         header->start_freq = ltt_chan->session->start_freq;
 417         header->freq_scale = ltt_chan->session->freq_scale;
 418 #endif //0
 419 }
 420
 421 /*
 422  * Size reserved for high priority events (interrupts, NMI, BH) at the end of a
 423  * nearly full buffer. User space won't use this last amount of space when in
 424  * blocking mode. This space also includes the event header that would be
 425  * written by this user space event.
 426  */
 427 #define LTT_RESERVE_CRITICAL            4096
 428
 429 /* Register and unregister function pointers */
 430
 431 enum ltt_module_function {
 432         LTT_FUNCTION_RUN_FILTER,
 433         LTT_FUNCTION_FILTER_CONTROL,
 434         LTT_FUNCTION_STATEDUMP
 435 };
 436
 437 extern int ltt_module_register(enum ltt_module_function name, void *function,
 438                                struct module *owner);
 439 extern void ltt_module_unregister(enum ltt_module_function name);
 440
 441 /* Exported control function */
 442
 443 void ltt_core_register(int (*function)(u8, void *));
 444
 445 void ltt_core_unregister(void);
 446
 447 extern
 448 void ltt_statedump_register_kprobes_dump(void (*callback)(void *call_data));
 449 extern
 450 void ltt_statedump_unregister_kprobes_dump(void (*callback)(void *call_data));
 451
 452 extern void ltt_dump_softirq_vec(void *call_data);
 453
 454 #ifdef CONFIG_HAVE_LTT_DUMP_TABLES
 455 extern void ltt_dump_sys_call_table(void *call_data);
 456 extern void ltt_dump_idt_table(void *call_data);
 457 #else
 458 static inline void ltt_dump_sys_call_table(void *call_data)
 459 {
 460 }
 461
 462 static inline void ltt_dump_idt_table(void *call_data)
 463 {
 464 }
 465 #endif
 466
 467 #endif /* _LTT_TRACER_H */