ltt-events.h

   1 #ifndef _LTT_EVENTS_H
   2 #define _LTT_EVENTS_H
   3
   4 /*
   5  * ltt-events.h
   6  *
   7  * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  *
   9  * Holds LTTng per-session event registry.
  10  */
  11
  12 #include <linux/list.h>
  13 #include <linux/uuid.h>
  14 #include <linux/kprobes.h>
  15 #include "ltt-debugfs-abi.h"
  16
  17 struct ltt_channel;
  18 struct ltt_session;
  19 struct lib_ring_buffer_ctx;
  20 struct perf_event;
  21
  22 /* Type description */
  23
  24 /* Update the astract_types name table in lttng-types.c along with this enum */
  25 enum abstract_types {
  26         atype_integer,
  27         atype_enum,
  28         atype_array,
  29         atype_sequence,
  30         atype_string,
  31         NR_ABSTRACT_TYPES,
  32 };
  33
  34 /* Update the string_encodings name table in lttng-types.c along with this enum */
  35 enum lttng_string_encodings {
  36         lttng_encode_none = 0,
  37         lttng_encode_UTF8 = 1,
  38         lttng_encode_ASCII = 2,
  39         NR_STRING_ENCODINGS,
  40 };
  41
  42 struct lttng_enum_entry {
  43         unsigned long long start, end;  /* start and end are inclusive */
  44         const char *string;
  45 };
  46
  47 #define __type_integer(_type, _byte_order, _base)               \
  48         {                                                       \
  49             .atype = atype_integer,                             \
  50             .u.basic.integer =                                  \
  51                 {                                               \
  52                   .size = sizeof(_type),                        \
  53                   .alignment = ltt_alignof(_type) * CHAR_BIT,   \
  54                   .signedness = is_signed_type(_type),          \
  55                   .reverse_byte_order = _byte_order != __BYTE_ORDER,    \
  56                   .base = _base,                                \
  57                   .encoding = lttng_encode_none,                \
  58                 },                                              \
  59         }                                                       \
  60
  61 struct lttng_integer_type {
  62         unsigned int size;              /* in bits */
  63         unsigned short alignment;       /* in bits */
  64         unsigned int signedness:1;
  65         unsigned int reverse_byte_order:1;
  66         unsigned int base;              /* 2, 8, 10, 16, for pretty print */
  67         enum lttng_string_encodings encoding;
  68 };
  69
  70 union _lttng_basic_type {
  71         struct lttng_integer_type integer;
  72         struct {
  73                 const char *name;
  74         } enumeration;
  75         struct {
  76                 enum lttng_string_encodings encoding;
  77         } string;
  78 };
  79
  80 struct lttng_basic_type {
  81         enum abstract_types atype;
  82         union {
  83                 union _lttng_basic_type basic;
  84         } u;
  85 };
  86
  87 struct lttng_type {
  88         enum abstract_types atype;
  89         union {
  90                 union _lttng_basic_type basic;
  91                 struct {
  92                         struct lttng_basic_type elem_type;
  93                         unsigned int length;            /* num. elems. */
  94                 } array;
  95                 struct {
  96                         struct lttng_basic_type length_type;
  97                         struct lttng_basic_type elem_type;
  98                 } sequence;
  99         } u;
 100 };
 101
 102 struct lttng_enum {
 103         const char *name;
 104         struct lttng_type container_type;
 105         const struct lttng_enum_entry *entries;
 106         unsigned int len;
 107 };
 108
 109 /* Event field description */
 110
 111 struct lttng_event_field {
 112         const char *name;
 113         struct lttng_type type;
 114 };
 115
 116 struct lttng_ctx_field {
 117         const char *name;
 118         struct lttng_type type;
 119         void *ctx_field_callback;
 120         union {
 121                 struct {
 122                         struct perf_event **e;  /* per-cpu array */
 123                         struct list_head *head;
 124                 } perf_counter;
 125         } u;
 126 };
 127
 128 struct lttng_ctx {
 129         const struct lttng_ctx_field *fields;
 130         unsigned int nr_fields;
 131         unsigned int allocated_fields;
 132 };
 133
 134 struct lttng_event_desc {
 135         const char *name;
 136         void *probe_callback;
 137         const struct lttng_event_ctx *ctx;      /* context */
 138         const struct lttng_event_field *fields; /* event payload */
 139         unsigned int nr_fields;
 140 };
 141
 142 struct lttng_probe_desc {
 143         const struct lttng_event_desc *event_desc;
 144         unsigned int nr_events;
 145         struct list_head head;                  /* chain registered probes */
 146 };
 147
 148 /*
 149  * ltt_event structure is referred to by the tracing fast path. It must be
 150  * kept small.
 151  */
 152 struct ltt_event {
 153         unsigned int id;
 154         struct ltt_channel *chan;
 155         const struct lttng_event_desc *desc;
 156         void *filter;
 157         enum lttng_kernel_instrumentation instrumentation;
 158         union {
 159                 struct {
 160                         struct kprobe kp;
 161                         char *symbol_name;
 162                 } kprobe;
 163                 struct {
 164                         char *symbol_name;
 165                 } ftrace;
 166         } u;
 167         struct list_head list;          /* Event list */
 168         int metadata_dumped:1;
 169 };
 170
 171 struct ltt_channel_ops {
 172         struct channel *(*channel_create)(const char *name,
 173                                 struct ltt_channel *ltt_chan,
 174                                 void *buf_addr,
 175                                 size_t subbuf_size, size_t num_subbuf,
 176                                 unsigned int switch_timer_interval,
 177                                 unsigned int read_timer_interval);
 178         void (*channel_destroy)(struct channel *chan);
 179         struct lib_ring_buffer *(*buffer_read_open)(struct channel *chan);
 180         void (*buffer_read_close)(struct lib_ring_buffer *buf);
 181         int (*event_reserve)(struct lib_ring_buffer_ctx *ctx);
 182         void (*event_commit)(struct lib_ring_buffer_ctx *ctx);
 183         void (*event_write)(struct lib_ring_buffer_ctx *ctx, const void *src,
 184                             size_t len);
 185         /*
 186          * packet_avail_size returns the available size in the current
 187          * packet. Note that the size returned is only a hint, since it
 188          * may change due to concurrent writes.
 189          */
 190         size_t (*packet_avail_size)(struct channel *chan);
 191         wait_queue_head_t *(*get_reader_wait_queue)(struct ltt_channel *chan);
 192 };
 193
 194 struct ltt_channel {
 195         unsigned int id;
 196         struct channel *chan;           /* Channel buffers */
 197         /* Event ID management */
 198         struct ltt_session *session;
 199         struct file *file;              /* File associated to channel */
 200         unsigned int free_event_id;     /* Next event ID to allocate */
 201         struct list_head list;          /* Channel list */
 202         wait_queue_head_t notify_wait;  /* Channel addition notif. waitqueue */
 203         struct ltt_channel_ops *ops;
 204         int header_type;                /* 0: unset, 1: compact, 2: large */
 205         int metadata_dumped:1;
 206 };
 207
 208 struct ltt_session {
 209         int active;                     /* Is trace session active ? */
 210         struct file *file;              /* File associated to session */
 211         struct ltt_channel *metadata;   /* Metadata channel */
 212         struct list_head chan;          /* Channel list head */
 213         struct list_head events;        /* Event list head */
 214         struct list_head list;          /* Session list */
 215         unsigned int free_chan_id;      /* Next chan ID to allocate */
 216         uuid_le uuid;                   /* Trace session unique ID */
 217         int metadata_dumped:1;
 218 };
 219
 220 struct ltt_transport {
 221         char *name;
 222         struct module *owner;
 223         struct list_head node;
 224         struct ltt_channel_ops ops;
 225 };
 226
 227 struct ltt_session *ltt_session_create(void);
 228 int ltt_session_start(struct ltt_session *session);
 229 int ltt_session_stop(struct ltt_session *session);
 230 void ltt_session_destroy(struct ltt_session *session);
 231
 232 struct ltt_channel *ltt_channel_create(struct ltt_session *session,
 233                                        const char *transport_name,
 234                                        void *buf_addr,
 235                                        size_t subbuf_size, size_t num_subbuf,
 236                                        unsigned int switch_timer_interval,
 237                                        unsigned int read_timer_interval);
 238 struct ltt_channel *ltt_global_channel_create(struct ltt_session *session,
 239                                        int overwrite, void *buf_addr,
 240                                        size_t subbuf_size, size_t num_subbuf,
 241                                        unsigned int switch_timer_interval,
 242                                        unsigned int read_timer_interval);
 243 void _ltt_channel_destroy(struct ltt_channel *chan);
 244
 245 struct ltt_event *ltt_event_create(struct ltt_channel *chan,
 246                                    char *name,
 247                                    struct lttng_kernel_event *event_param,
 248                                    void *filter);
 249 int ltt_event_unregister(struct ltt_event *event);
 250
 251 void ltt_transport_register(struct ltt_transport *transport);
 252 void ltt_transport_unregister(struct ltt_transport *transport);
 253
 254 int ltt_debugfs_abi_init(void);
 255 void ltt_debugfs_abi_exit(void);
 256
 257 int ltt_probe_register(struct lttng_probe_desc *desc);
 258 void ltt_probe_unregister(struct lttng_probe_desc *desc);
 259 const struct lttng_event_desc *ltt_event_get(const char *name);
 260 void ltt_event_put(const struct lttng_event_desc *desc);
 261 int ltt_probes_init(void);
 262 void ltt_probes_exit(void);
 263
 264 #ifdef CONFIG_KPROBES
 265 int lttng_kprobes_register(const char *name,
 266                 const char *symbol_name,
 267                 uint64_t offset,
 268                 uint64_t addr,
 269                 struct ltt_event *event);
 270 void lttng_kprobes_unregister(struct ltt_event *event);
 271 #else
 272 static inline
 273 int lttng_kprobes_register(const char *name,
 274                 const char *symbol_name,
 275                 uint64_t offset,
 276                 uint64_t addr,
 277                 struct ltt_event *event)
 278 {
 279         return -ENOSYS;
 280 }
 281
 282 void lttng_kprobes_unregister(struct ltt_event *event)
 283 {
 284 }
 285 #endif
 286
 287 #ifdef CONFIG_DYNAMIC_FTRACE
 288 int lttng_ftrace_register(const char *name,
 289                           const char *symbol_name,
 290                           struct ltt_event *event);
 291 void lttng_ftrace_unregister(struct ltt_event *event);
 292 #else
 293 static inline
 294 int lttng_ftrace_register(const char *name,
 295                           const char *symbol_name,
 296                           struct ltt_event *event)
 297 {
 298         return -ENOSYS;
 299 }
 300
 301 static inline
 302 void lttng_ftrace_unregister(struct ltt_event *event)
 303 {
 304 }
 305 #endif
 306 #endif /* _LTT_EVENTS_H */