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 <asm/atomic.h>
  20 #include <asm/local.h>
  21
  22 #include "wrapper/trace-clock.h"
  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 /*
  76  * Hardcoded event headers
  77  *
  78  * event header for a trace with active heartbeat : 27 bits timestamps
  79  *
  80  * headers are 32-bits aligned. In order to insure such alignment, a dynamic per
  81  * trace alignment value must be done.
  82  *
  83  * Remember that the C compiler does align each member on the boundary
  84  * equivalent to their own size.
  85  *
  86  * As relay subbuffers are aligned on pages, we are sure that they are 4 and 8
  87  * bytes aligned, so the buffer header and trace header are aligned.
  88  *
  89  * Event headers are aligned depending on the trace alignment option.
  90  *
  91  * Note using C structure bitfields for cross-endianness and portability
  92  * concerns.
  93  */
  94
  95 #define LTT_RESERVED_EVENTS     3
  96 #define LTT_EVENT_BITS          5
  97 #define LTT_FREE_EVENTS         ((1 << LTT_EVENT_BITS) - LTT_RESERVED_EVENTS)
  98 #define LTT_TSC_BITS            27
  99 #define LTT_TSC_MASK            ((1 << LTT_TSC_BITS) - 1)
 100
 101 struct event_header {
 102         u32 id_time;            /* 5 bits event id (MSB); 27 bits time (LSB) */
 103 };
 104
 105 /* Reservation flags */
 106 #define LTT_RFLAG_ID                    (1 << 0)
 107 #define LTT_RFLAG_ID_SIZE               (1 << 1)
 108 #define LTT_RFLAG_ID_SIZE_TSC           (1 << 2)
 109
 110 #define LTT_MAX_SMALL_SIZE              0xFFFFU
 111
 112 /*
 113  * We use asm/timex.h : cpu_khz/HZ variable in here : we might have to deal
 114  * specifically with CPU frequency scaling someday, so using an interpolation
 115  * between the start and end of buffer values is not flexible enough. Using an
 116  * immediate frequency value permits to calculate directly the times for parts
 117  * of a buffer that would be before a frequency change.
 118  *
 119  * Keep the natural field alignment for _each field_ within this structure if
 120  * you ever add/remove a field from this header. Packed attribute is not used
 121  * because gcc generates poor code on at least powerpc and mips. Don't ever
 122  * let gcc add padding between the structure elements.
 123  */
 124 struct packet_header {
 125         uint32_t magic;                 /*
 126                                          * Trace magic number.
 127                                          * contains endianness information.
 128                                          */
 129         uint8_t trace_uuid[16];
 130         uint32_t stream_id;
 131         uint64_t timestamp_begin;       /* Cycle count at subbuffer start */
 132         uint64_t timestamp_end; /* Cycle count at subbuffer end */
 133         uint32_t content_size;          /* Size of data in subbuffer */
 134         uint32_t packet_size;           /* Subbuffer size (include padding) */
 135         uint32_t events_lost;           /*
 136                                          * Events lost in this subbuffer since
 137                                          * the beginning of the trace.
 138                                          * (may overflow)
 139                                          */
 140         /* TODO: move to metadata */
 141 #if 0
 142         uint8_t major_version;
 143         uint8_t minor_version;
 144         uint8_t arch_size;              /* Architecture pointer size */
 145         uint8_t alignment;              /* LTT data alignment */
 146         uint64_t start_time_sec;        /* NTP-corrected start time */
 147         uint64_t start_time_usec;
 148         uint64_t start_freq;            /*
 149                                          * Frequency at trace start,
 150                                          * used all along the trace.
 151                                          */
 152         uint32_t freq_scale;            /* Frequency scaling (divisor) */
 153 #endif //0
 154         uint8_t header_end[0];          /* End of header */
 155 };
 156
 157 static inline notrace u64 lib_ring_buffer_clock_read(struct channel *chan)
 158 {
 159         return trace_clock_read64();
 160 }
 161
 162 /*
 163  * record_header_size - Calculate the header size and padding necessary.
 164  * @config: ring buffer instance configuration
 165  * @chan: channel
 166  * @offset: offset in the write buffer
 167  * @data_size: size of the payload
 168  * @pre_header_padding: padding to add before the header (output)
 169  * @rflags: reservation flags
 170  * @ctx: reservation context
 171  *
 172  * Returns the event header size (including padding).
 173  *
 174  * Important note :
 175  * The event header must be 32-bits. The total offset calculated here :
 176  *
 177  * Alignment of header struct on 32 bits (min arch size, header size)
 178  * + sizeof(header struct)  (32-bits)
 179  * + (opt) u16 (ext. event id)
 180  * + (opt) u16 (event_size)
 181  *             (if event_size == LTT_MAX_SMALL_SIZE, has ext. event size)
 182  * + (opt) u32 (ext. event size)
 183  * + (opt) u64 full TSC (aligned on min(64-bits, arch size))
 184  *
 185  * The payload must itself determine its own alignment from the biggest type it
 186  * contains.
 187  */
 188 static __inline__
 189 unsigned char record_header_size(const struct lib_ring_buffer_config *config,
 190                                  struct channel *chan, size_t offset,
 191                                  size_t data_size, size_t *pre_header_padding,
 192                                  unsigned int rflags,
 193                                  struct lib_ring_buffer_ctx *ctx)
 194 {
 195         size_t orig_offset = offset;
 196         size_t padding;
 197
 198         BUILD_BUG_ON(sizeof(struct event_header) != sizeof(u32));
 199
 200         padding = lib_ring_buffer_align(offset,
 201                                         sizeof(struct event_header));
 202         offset += padding;
 203         offset += sizeof(struct event_header);
 204
 205         if (unlikely(rflags)) {
 206                 switch (rflags) {
 207                 case LTT_RFLAG_ID_SIZE_TSC:
 208                         offset += sizeof(u16) + sizeof(u16);
 209                         if (data_size >= LTT_MAX_SMALL_SIZE)
 210                                 offset += sizeof(u32);
 211                         offset += lib_ring_buffer_align(offset, sizeof(u64));
 212                         offset += sizeof(u64);
 213                         break;
 214                 case LTT_RFLAG_ID_SIZE:
 215                         offset += sizeof(u16) + sizeof(u16);
 216                         if (data_size >= LTT_MAX_SMALL_SIZE)
 217                                 offset += sizeof(u32);
 218                         break;
 219                 case LTT_RFLAG_ID:
 220                         offset += sizeof(u16);
 221                         break;
 222                 }
 223         }
 224
 225         *pre_header_padding = padding;
 226         return offset - orig_offset;
 227 }
 228
 229 #include "wrapper/ringbuffer/api.h"
 230
 231 extern
 232 void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config,
 233                                  struct lib_ring_buffer_ctx *ctx,
 234                                  u16 eID, u32 event_size);
 235
 236 /*
 237  * ltt_write_event_header
 238  *
 239  * Writes the event header to the offset (already aligned on 32-bits).
 240  *
 241  * @config: ring buffer instance configuration
 242  * @ctx: reservation context
 243  * @eID : event ID
 244  * @event_size : size of the event, excluding the event header.
 245  */
 246 static __inline__
 247 void ltt_write_event_header(const struct lib_ring_buffer_config *config,
 248                             struct lib_ring_buffer_ctx *ctx,
 249                             u16 eID, u32 event_size)
 250 {
 251         struct event_header header;
 252
 253         if (unlikely(ctx->rflags))
 254                 goto slow_path;
 255
 256         header.id_time = eID << LTT_TSC_BITS;
 257         header.id_time |= (u32)ctx->tsc & LTT_TSC_MASK;
 258         lib_ring_buffer_write(config, ctx, &header, sizeof(header));
 259
 260 slow_path:
 261         ltt_write_event_header_slow(config, ctx, eID, event_size);
 262 }
 263
 264 /* Tracer properties */
 265 #define CTF_MAGIC_NUMBER                0xC1FC1FC1
 266 #define LTT_TRACER_VERSION_MAJOR        3
 267 #define LTT_TRACER_VERSION_MINOR        0
 268
 269 /**
 270  * ltt_write_trace_header - Write trace header
 271  * @priv: Private data (struct trace)
 272  * @header: Memory address where the information must be written to
 273  */
 274 static __inline__
 275 void write_trace_header(const struct lib_ring_buffer_config *config,
 276                         struct packet_header *header)
 277 {
 278         header->magic = CTF_MAGIC_NUMBER;
 279 #if 0
 280         /* TODO: move start time to metadata */
 281         header->major_version = LTT_TRACER_VERSION_MAJOR;
 282         header->minor_version = LTT_TRACER_VERSION_MINOR;
 283         header->arch_size = sizeof(void *);
 284         header->alignment = lib_ring_buffer_get_alignment(config);
 285         header->start_time_sec = ltt_chan->session->start_time.tv_sec;
 286         header->start_time_usec = ltt_chan->session->start_time.tv_usec;
 287         header->start_freq = ltt_chan->session->start_freq;
 288         header->freq_scale = ltt_chan->session->freq_scale;
 289 #endif //0
 290 }
 291
 292 /*
 293  * Size reserved for high priority events (interrupts, NMI, BH) at the end of a
 294  * nearly full buffer. User space won't use this last amount of space when in
 295  * blocking mode. This space also includes the event header that would be
 296  * written by this user space event.
 297  */
 298 #define LTT_RESERVE_CRITICAL            4096
 299
 300 /* Register and unregister function pointers */
 301
 302 enum ltt_module_function {
 303         LTT_FUNCTION_RUN_FILTER,
 304         LTT_FUNCTION_FILTER_CONTROL,
 305         LTT_FUNCTION_STATEDUMP
 306 };
 307
 308 extern int ltt_module_register(enum ltt_module_function name, void *function,
 309                                struct module *owner);
 310 extern void ltt_module_unregister(enum ltt_module_function name);
 311
 312 /* Exported control function */
 313
 314 void ltt_core_register(int (*function)(u8, void *));
 315
 316 void ltt_core_unregister(void);
 317
 318 extern
 319 void ltt_statedump_register_kprobes_dump(void (*callback)(void *call_data));
 320 extern
 321 void ltt_statedump_unregister_kprobes_dump(void (*callback)(void *call_data));
 322
 323 extern void ltt_dump_softirq_vec(void *call_data);
 324
 325 #ifdef CONFIG_HAVE_LTT_DUMP_TABLES
 326 extern void ltt_dump_sys_call_table(void *call_data);
 327 extern void ltt_dump_idt_table(void *call_data);
 328 #else
 329 static inline void ltt_dump_sys_call_table(void *call_data)
 330 {
 331 }
 332
 333 static inline void ltt_dump_idt_table(void *call_data)
 334 {
 335 }
 336 #endif
 337
 338 #endif /* _LTT_TRACER_H */