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 struct perf_event_attr;
  22
  23 /* Type description */
  24
  25 /* Update the astract_types name table in lttng-types.c along with this enum */
  26 enum abstract_types {
  27         atype_integer,
  28         atype_enum,
  29         atype_array,
  30         atype_sequence,
  31         atype_string,
  32         NR_ABSTRACT_TYPES,
  33 };
  34
  35 /* Update the string_encodings name table in lttng-types.c along with this enum */
  36 enum lttng_string_encodings {
  37         lttng_encode_none = 0,
  38         lttng_encode_UTF8 = 1,
  39         lttng_encode_ASCII = 2,
  40         NR_STRING_ENCODINGS,
  41 };
  42
  43 struct lttng_enum_entry {
  44         unsigned long long start, end;  /* start and end are inclusive */
  45         const char *string;
  46 };
  47
  48 #define __type_integer(_type, _byte_order, _base)               \
  49         {                                                       \
  50             .atype = atype_integer,                             \
  51             .u.basic.integer =                                  \
  52                 {                                               \
  53                   .size = sizeof(_type),                        \
  54                   .alignment = ltt_alignof(_type) * CHAR_BIT,   \
  55                   .signedness = is_signed_type(_type),          \
  56                   .reverse_byte_order = _byte_order != __BYTE_ORDER,    \
  57                   .base = _base,                                \
  58                   .encoding = lttng_encode_none,                \
  59                 },                                              \
  60         }                                                       \
  61
  62 struct lttng_integer_type {
  63         unsigned int size;              /* in bits */
  64         unsigned short alignment;       /* in bits */
  65         unsigned int signedness:1;
  66         unsigned int reverse_byte_order:1;
  67         unsigned int base;              /* 2, 8, 10, 16, for pretty print */
  68         enum lttng_string_encodings encoding;
  69 };
  70
  71 union _lttng_basic_type {
  72         struct lttng_integer_type integer;
  73         struct {
  74                 const char *name;
  75         } enumeration;
  76         struct {
  77                 enum lttng_string_encodings encoding;
  78         } string;
  79 };
  80
  81 struct lttng_basic_type {
  82         enum abstract_types atype;
  83         union {
  84                 union _lttng_basic_type basic;
  85         } u;
  86 };
  87
  88 struct lttng_type {
  89         enum abstract_types atype;
  90         union {
  91                 union _lttng_basic_type basic;
  92                 struct {
  93                         struct lttng_basic_type elem_type;
  94                         unsigned int length;            /* num. elems. */
  95                 } array;
  96                 struct {
  97                         struct lttng_basic_type length_type;
  98                         struct lttng_basic_type elem_type;
  99                 } sequence;
 100         } u;
 101 };
 102
 103 struct lttng_enum {
 104         const char *name;
 105         struct lttng_type container_type;
 106         const struct lttng_enum_entry *entries;
 107         unsigned int len;
 108 };
 109
 110 /* Event field description */
 111
 112 struct lttng_event_field {
 113         const char *name;
 114         struct lttng_type type;
 115 };
 116
 117 struct lttng_ctx_field {
 118         const char *name;
 119         struct lttng_type type;
 120         void *callback;
 121         union {
 122                 struct {
 123                         struct perf_event **e;  /* per-cpu array */
 124                         struct list_head head;
 125                         struct perf_event_attr *attr;
 126                 } perf_counter;
 127         } u;
 128 };
 129
 130 struct lttng_ctx {
 131         struct lttng_ctx_field *fields;
 132         unsigned int nr_fields;
 133         unsigned int allocated_fields;
 134 };
 135
 136 struct lttng_event_desc {
 137         const char *name;
 138         void *probe_callback;
 139         const struct lttng_event_ctx *ctx;      /* context */
 140         const struct lttng_event_field *fields; /* event payload */
 141         unsigned int nr_fields;
 142 };
 143
 144 struct lttng_probe_desc {
 145         const struct lttng_event_desc *event_desc;
 146         unsigned int nr_events;
 147         struct list_head head;                  /* chain registered probes */
 148 };
 149
 150 /*
 151  * ltt_event structure is referred to by the tracing fast path. It must be
 152  * kept small.
 153  */
 154 struct ltt_event {
 155         unsigned int id;
 156         struct ltt_channel *chan;
 157         const struct lttng_event_desc *desc;
 158         void *filter;
 159         enum lttng_kernel_instrumentation instrumentation;
 160         union {
 161                 struct {
 162                         struct kprobe kp;
 163                         char *symbol_name;
 164                 } kprobe;
 165                 struct {
 166                         char *symbol_name;
 167                 } ftrace;
 168         } u;
 169         struct list_head list;          /* Event list */
 170         int metadata_dumped:1;
 171 };
 172
 173 struct ltt_channel_ops {
 174         struct channel *(*channel_create)(const char *name,
 175                                 struct ltt_channel *ltt_chan,
 176                                 void *buf_addr,
 177                                 size_t subbuf_size, size_t num_subbuf,
 178                                 unsigned int switch_timer_interval,
 179                                 unsigned int read_timer_interval);
 180         void (*channel_destroy)(struct channel *chan);
 181         struct lib_ring_buffer *(*buffer_read_open)(struct channel *chan);
 182         void (*buffer_read_close)(struct lib_ring_buffer *buf);
 183         int (*event_reserve)(struct lib_ring_buffer_ctx *ctx);
 184         void (*event_commit)(struct lib_ring_buffer_ctx *ctx);
 185         void (*event_write)(struct lib_ring_buffer_ctx *ctx, const void *src,
 186                             size_t len);
 187         /*
 188          * packet_avail_size returns the available size in the current
 189          * packet. Note that the size returned is only a hint, since it
 190          * may change due to concurrent writes.
 191          */
 192         size_t (*packet_avail_size)(struct channel *chan);
 193         wait_queue_head_t *(*get_reader_wait_queue)(struct ltt_channel *chan);
 194 };
 195
 196 struct ltt_channel {
 197         unsigned int id;
 198         struct channel *chan;           /* Channel buffers */
 199         /* Event ID management */
 200         struct ltt_session *session;
 201         struct file *file;              /* File associated to channel */
 202         unsigned int free_event_id;     /* Next event ID to allocate */
 203         struct list_head list;          /* Channel list */
 204         wait_queue_head_t notify_wait;  /* Channel addition notif. waitqueue */
 205         struct ltt_channel_ops *ops;
 206         int header_type;                /* 0: unset, 1: compact, 2: large */
 207         int metadata_dumped:1;
 208 };
 209
 210 struct ltt_session {
 211         int active;                     /* Is trace session active ? */
 212         struct file *file;              /* File associated to session */
 213         struct ltt_channel *metadata;   /* Metadata channel */
 214         struct list_head chan;          /* Channel list head */
 215         struct list_head events;        /* Event list head */
 216         struct list_head list;          /* Session list */
 217         unsigned int free_chan_id;      /* Next chan ID to allocate */
 218         uuid_le uuid;                   /* Trace session unique ID */
 219         int metadata_dumped:1;
 220 };
 221
 222 struct ltt_transport {
 223         char *name;
 224         struct module *owner;
 225         struct list_head node;
 226         struct ltt_channel_ops ops;
 227 };
 228
 229 struct ltt_session *ltt_session_create(void);
 230 int ltt_session_start(struct ltt_session *session);
 231 int ltt_session_stop(struct ltt_session *session);
 232 void ltt_session_destroy(struct ltt_session *session);
 233
 234 struct ltt_channel *ltt_channel_create(struct ltt_session *session,
 235                                        const char *transport_name,
 236                                        void *buf_addr,
 237                                        size_t subbuf_size, size_t num_subbuf,
 238                                        unsigned int switch_timer_interval,
 239                                        unsigned int read_timer_interval);
 240 struct ltt_channel *ltt_global_channel_create(struct ltt_session *session,
 241                                        int overwrite, void *buf_addr,
 242                                        size_t subbuf_size, size_t num_subbuf,
 243                                        unsigned int switch_timer_interval,
 244                                        unsigned int read_timer_interval);
 245 void _ltt_channel_destroy(struct ltt_channel *chan);
 246
 247 struct ltt_event *ltt_event_create(struct ltt_channel *chan,
 248                                    char *name,
 249                                    struct lttng_kernel_event *event_param,
 250                                    void *filter);
 251 int ltt_event_unregister(struct ltt_event *event);
 252
 253 void ltt_transport_register(struct ltt_transport *transport);
 254 void ltt_transport_unregister(struct ltt_transport *transport);
 255
 256 int ltt_debugfs_abi_init(void);
 257 void ltt_debugfs_abi_exit(void);
 258
 259 int ltt_probe_register(struct lttng_probe_desc *desc);
 260 void ltt_probe_unregister(struct lttng_probe_desc *desc);
 261 const struct lttng_event_desc *ltt_event_get(const char *name);
 262 void ltt_event_put(const struct lttng_event_desc *desc);
 263 int ltt_probes_init(void);
 264 void ltt_probes_exit(void);
 265
 266 #ifdef CONFIG_KPROBES
 267 int lttng_kprobes_register(const char *name,
 268                 const char *symbol_name,
 269                 uint64_t offset,
 270                 uint64_t addr,
 271                 struct ltt_event *event);
 272 void lttng_kprobes_unregister(struct ltt_event *event);
 273 #else
 274 static inline
 275 int lttng_kprobes_register(const char *name,
 276                 const char *symbol_name,
 277                 uint64_t offset,
 278                 uint64_t addr,
 279                 struct ltt_event *event)
 280 {
 281         return -ENOSYS;
 282 }
 283
 284 static inline
 285 void lttng_kprobes_unregister(struct ltt_event *event)
 286 {
 287 }
 288 #endif
 289
 290 #ifdef CONFIG_DYNAMIC_FTRACE
 291 int lttng_ftrace_register(const char *name,
 292                           const char *symbol_name,
 293                           struct ltt_event *event);
 294 void lttng_ftrace_unregister(struct ltt_event *event);
 295 #else
 296 static inline
 297 int lttng_ftrace_register(const char *name,
 298                           const char *symbol_name,
 299                           struct ltt_event *event)
 300 {
 301         return -ENOSYS;
 302 }
 303
 304 static inline
 305 void lttng_ftrace_unregister(struct ltt_event *event)
 306 {
 307 }
 308 #endif
 309 #endif /* _LTT_EVENTS_H */