kernel/trace/trace_probe.h

   1 /*
   2  * Common header file for probe-based Dynamic events.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  16  *
  17  * This code was copied from kernel/trace/trace_kprobe.h written by
  18  * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
  19  *
  20  * Updates to make this generic:
  21  * Copyright (C) IBM Corporation, 2010-2011
  22  * Author:     Srikar Dronamraju
  23  */
  24
  25 #include <linux/seq_file.h>
  26 #include <linux/slab.h>
  27 #include <linux/smp.h>
  28 #include <linux/tracefs.h>
  29 #include <linux/types.h>
  30 #include <linux/string.h>
  31 #include <linux/ctype.h>
  32 #include <linux/ptrace.h>
  33 #include <linux/perf_event.h>
  34 #include <linux/kprobes.h>
  35 #include <linux/stringify.h>
  36 #include <linux/limits.h>
  37 #include <linux/uaccess.h>
  38 #include <asm/bitsperlong.h>
  39
  40 #include "trace.h"
  41 #include "trace_output.h"
  42
  43 #define MAX_TRACE_ARGS          128
  44 #define MAX_ARGSTR_LEN          63
  45 #define MAX_EVENT_NAME_LEN      64
  46 #define MAX_STRING_SIZE         PATH_MAX
  47
  48 /* Reserved field names */
  49 #define FIELD_STRING_IP         "__probe_ip"
  50 #define FIELD_STRING_RETIP      "__probe_ret_ip"
  51 #define FIELD_STRING_FUNC       "__probe_func"
  52
  53 #undef DEFINE_FIELD
  54 #define DEFINE_FIELD(type, item, name, is_signed)                       \
  55         do {                                                            \
  56                 ret = trace_define_field(event_call, #type, name,       \
  57                                          offsetof(typeof(field), item), \
  58                                          sizeof(field.item), is_signed, \
  59                                          FILTER_OTHER);                 \
  60                 if (ret)                                                \
  61                         return ret;                                     \
  62         } while (0)
  63
  64
  65 /* Flags for trace_probe */
  66 #define TP_FLAG_TRACE           1
  67 #define TP_FLAG_PROFILE         2
  68 #define TP_FLAG_REGISTERED      4
  69
  70
  71 /* data_rloc: data relative location, compatible with u32 */
  72 #define make_data_rloc(len, roffs)      \
  73         (((u32)(len) << 16) | ((u32)(roffs) & 0xffff))
  74 #define get_rloc_len(dl)                ((u32)(dl) >> 16)
  75 #define get_rloc_offs(dl)               ((u32)(dl) & 0xffff)
  76
  77 /*
  78  * Convert data_rloc to data_loc:
  79  *  data_rloc stores the offset from data_rloc itself, but data_loc
  80  *  stores the offset from event entry.
  81  */
  82 #define convert_rloc_to_loc(dl, offs)   ((u32)(dl) + (offs))
  83
  84 static nokprobe_inline void *get_rloc_data(u32 *dl)
  85 {
  86         return (u8 *)dl + get_rloc_offs(*dl);
  87 }
  88
  89 /* For data_loc conversion */
  90 static nokprobe_inline void *get_loc_data(u32 *dl, void *ent)
  91 {
  92         return (u8 *)ent + get_rloc_offs(*dl);
  93 }
  94
  95 /* Data fetch function type */
  96 typedef void (*fetch_func_t)(struct pt_regs *, void *, void *);
  97 /* Printing function type */
  98 typedef int (*print_type_func_t)(struct trace_seq *, const char *, void *, void *);
  99
 100 /* Fetch types */
 101 enum {
 102         FETCH_MTD_reg = 0,
 103         FETCH_MTD_stack,
 104         FETCH_MTD_retval,
 105         FETCH_MTD_comm,
 106         FETCH_MTD_memory,
 107         FETCH_MTD_symbol,
 108         FETCH_MTD_deref,
 109         FETCH_MTD_bitfield,
 110         FETCH_MTD_file_offset,
 111         FETCH_MTD_END,
 112 };
 113
 114 /* Fetch type information table */
 115 struct fetch_type {
 116         const char              *name;          /* Name of type */
 117         size_t                  size;           /* Byte size of type */
 118         int                     is_signed;      /* Signed flag */
 119         print_type_func_t       print;          /* Print functions */
 120         const char              *fmt;           /* Fromat string */
 121         const char              *fmttype;       /* Name in format file */
 122         /* Fetch functions */
 123         fetch_func_t            fetch[FETCH_MTD_END];
 124 };
 125
 126 struct fetch_param {
 127         fetch_func_t            fn;
 128         void                    *data;
 129 };
 130
 131 /* For defining macros, define string/string_size types */
 132 typedef u32 string;
 133 typedef u32 string_size;
 134
 135 #define PRINT_TYPE_FUNC_NAME(type)      print_type_##type
 136 #define PRINT_TYPE_FMT_NAME(type)       print_type_format_##type
 137
 138 /* Printing  in basic type function template */
 139 #define DECLARE_BASIC_PRINT_TYPE_FUNC(type)                             \
 140 int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name,   \
 141                                 void *data, void *ent);                 \
 142 extern const char PRINT_TYPE_FMT_NAME(type)[]
 143
 144 DECLARE_BASIC_PRINT_TYPE_FUNC(u8);
 145 DECLARE_BASIC_PRINT_TYPE_FUNC(u16);
 146 DECLARE_BASIC_PRINT_TYPE_FUNC(u32);
 147 DECLARE_BASIC_PRINT_TYPE_FUNC(u64);
 148 DECLARE_BASIC_PRINT_TYPE_FUNC(s8);
 149 DECLARE_BASIC_PRINT_TYPE_FUNC(s16);
 150 DECLARE_BASIC_PRINT_TYPE_FUNC(s32);
 151 DECLARE_BASIC_PRINT_TYPE_FUNC(s64);
 152 DECLARE_BASIC_PRINT_TYPE_FUNC(x8);
 153 DECLARE_BASIC_PRINT_TYPE_FUNC(x16);
 154 DECLARE_BASIC_PRINT_TYPE_FUNC(x32);
 155 DECLARE_BASIC_PRINT_TYPE_FUNC(x64);
 156
 157 DECLARE_BASIC_PRINT_TYPE_FUNC(string);
 158
 159 #define FETCH_FUNC_NAME(method, type)   fetch_##method##_##type
 160
 161 /* Declare macro for basic types */
 162 #define DECLARE_FETCH_FUNC(method, type)                                \
 163 extern void FETCH_FUNC_NAME(method, type)(struct pt_regs *regs,         \
 164                                           void *data, void *dest)
 165
 166 #define DECLARE_BASIC_FETCH_FUNCS(method)       \
 167 DECLARE_FETCH_FUNC(method, u8);                 \
 168 DECLARE_FETCH_FUNC(method, u16);                \
 169 DECLARE_FETCH_FUNC(method, u32);                \
 170 DECLARE_FETCH_FUNC(method, u64)
 171
 172 DECLARE_BASIC_FETCH_FUNCS(reg);
 173 #define fetch_reg_string                        NULL
 174 #define fetch_reg_string_size                   NULL
 175
 176 DECLARE_BASIC_FETCH_FUNCS(retval);
 177 #define fetch_retval_string                     NULL
 178 #define fetch_retval_string_size                NULL
 179
 180 DECLARE_BASIC_FETCH_FUNCS(symbol);
 181 DECLARE_FETCH_FUNC(symbol, string);
 182 DECLARE_FETCH_FUNC(symbol, string_size);
 183
 184 DECLARE_BASIC_FETCH_FUNCS(deref);
 185 DECLARE_FETCH_FUNC(deref, string);
 186 DECLARE_FETCH_FUNC(deref, string_size);
 187
 188 DECLARE_BASIC_FETCH_FUNCS(bitfield);
 189 #define fetch_bitfield_string                   NULL
 190 #define fetch_bitfield_string_size              NULL
 191
 192 /* comm only makes sense as a string */
 193 #define fetch_comm_u8           NULL
 194 #define fetch_comm_u16          NULL
 195 #define fetch_comm_u32          NULL
 196 #define fetch_comm_u64          NULL
 197 DECLARE_FETCH_FUNC(comm, string);
 198 DECLARE_FETCH_FUNC(comm, string_size);
 199
 200 /*
 201  * Define macro for basic types - we don't need to define s* types, because
 202  * we have to care only about bitwidth at recording time.
 203  */
 204 #define DEFINE_BASIC_FETCH_FUNCS(method) \
 205 DEFINE_FETCH_##method(u8)               \
 206 DEFINE_FETCH_##method(u16)              \
 207 DEFINE_FETCH_##method(u32)              \
 208 DEFINE_FETCH_##method(u64)
 209
 210 /* Default (unsigned long) fetch type */
 211 #define __DEFAULT_FETCH_TYPE(t) x##t
 212 #define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
 213 #define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
 214 #define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
 215
 216 #define ASSIGN_FETCH_FUNC(method, type) \
 217         [FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type)
 218
 219 #define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \
 220         {.name = _name,                         \
 221          .size = _size,                                 \
 222          .is_signed = sign,                             \
 223          .print = PRINT_TYPE_FUNC_NAME(ptype),          \
 224          .fmt = PRINT_TYPE_FMT_NAME(ptype),             \
 225          .fmttype = _fmttype,                           \
 226          .fetch = {                                     \
 227 ASSIGN_FETCH_FUNC(reg, ftype),                          \
 228 ASSIGN_FETCH_FUNC(stack, ftype),                        \
 229 ASSIGN_FETCH_FUNC(retval, ftype),                       \
 230 ASSIGN_FETCH_FUNC(comm, ftype),                         \
 231 ASSIGN_FETCH_FUNC(memory, ftype),                       \
 232 ASSIGN_FETCH_FUNC(symbol, ftype),                       \
 233 ASSIGN_FETCH_FUNC(deref, ftype),                        \
 234 ASSIGN_FETCH_FUNC(bitfield, ftype),                     \
 235 ASSIGN_FETCH_FUNC(file_offset, ftype),                  \
 236           }                                             \
 237         }
 238
 239 #define ASSIGN_FETCH_TYPE(ptype, ftype, sign)                   \
 240         __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
 241
 242 /* If ptype is an alias of atype, use this macro (show atype in format) */
 243 #define ASSIGN_FETCH_TYPE_ALIAS(ptype, atype, ftype, sign)              \
 244         __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #atype)
 245
 246 #define ASSIGN_FETCH_TYPE_END {}
 247
 248 #define FETCH_TYPE_STRING       0
 249 #define FETCH_TYPE_STRSIZE      1
 250
 251 #ifdef CONFIG_KPROBE_EVENTS
 252 struct symbol_cache;
 253 unsigned long update_symbol_cache(struct symbol_cache *sc);
 254 void free_symbol_cache(struct symbol_cache *sc);
 255 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset);
 256 #else
 257 /* uprobes do not support symbol fetch methods */
 258 #define fetch_symbol_u8                 NULL
 259 #define fetch_symbol_u16                NULL
 260 #define fetch_symbol_u32                NULL
 261 #define fetch_symbol_u64                NULL
 262 #define fetch_symbol_string             NULL
 263 #define fetch_symbol_string_size        NULL
 264
 265 struct symbol_cache {
 266 };
 267 static inline unsigned long __used update_symbol_cache(struct symbol_cache *sc)
 268 {
 269         return 0;
 270 }
 271
 272 static inline void __used free_symbol_cache(struct symbol_cache *sc)
 273 {
 274 }
 275
 276 static inline struct symbol_cache * __used
 277 alloc_symbol_cache(const char *sym, long offset)
 278 {
 279         return NULL;
 280 }
 281 #endif /* CONFIG_KPROBE_EVENTS */
 282
 283 struct probe_arg {
 284         struct fetch_param      fetch;
 285         struct fetch_param      fetch_size;
 286         unsigned int            offset; /* Offset from argument entry */
 287         const char              *name;  /* Name of this argument */
 288         const char              *comm;  /* Command of this argument */
 289         const struct fetch_type *type;  /* Type of this argument */
 290 };
 291
 292 struct trace_probe {
 293         unsigned int                    flags;  /* For TP_FLAG_* */
 294         struct trace_event_class        class;
 295         struct trace_event_call         call;
 296         struct list_head                files;
 297         ssize_t                         size;   /* trace entry size */
 298         unsigned int                    nr_args;
 299         struct probe_arg                args[];
 300 };
 301
 302 struct event_file_link {
 303         struct trace_event_file         *file;
 304         struct list_head                list;
 305 };
 306
 307 static inline bool trace_probe_is_enabled(struct trace_probe *tp)
 308 {
 309         return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE));
 310 }
 311
 312 static inline bool trace_probe_is_registered(struct trace_probe *tp)
 313 {
 314         return !!(tp->flags & TP_FLAG_REGISTERED);
 315 }
 316
 317 static nokprobe_inline void call_fetch(struct fetch_param *fprm,
 318                                  struct pt_regs *regs, void *dest)
 319 {
 320         return fprm->fn(regs, fprm->data, dest);
 321 }
 322
 323 /* Check the name is good for event/group/fields */
 324 static inline bool is_good_name(const char *name)
 325 {
 326         if (!isalpha(*name) && *name != '_')
 327                 return false;
 328         while (*++name != '\0') {
 329                 if (!isalpha(*name) && !isdigit(*name) && *name != '_')
 330                         return false;
 331         }
 332         return true;
 333 }
 334
 335 static inline struct event_file_link *
 336 find_event_file_link(struct trace_probe *tp, struct trace_event_file *file)
 337 {
 338         struct event_file_link *link;
 339
 340         list_for_each_entry(link, &tp->files, list)
 341                 if (link->file == file)
 342                         return link;
 343
 344         return NULL;
 345 }
 346
 347 extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
 348                    struct probe_arg *parg, bool is_return, bool is_kprobe,
 349                    const struct fetch_type *ftbl);
 350
 351 extern int traceprobe_conflict_field_name(const char *name,
 352                                struct probe_arg *args, int narg);
 353
 354 extern void traceprobe_update_arg(struct probe_arg *arg);
 355 extern void traceprobe_free_probe_arg(struct probe_arg *arg);
 356
 357 extern int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset);
 358
 359 extern ssize_t traceprobe_probes_write(struct file *file,
 360                 const char __user *buffer, size_t count, loff_t *ppos,
 361                 int (*createfn)(int, char**));
 362
 363 extern int traceprobe_command(const char *buf, int (*createfn)(int, char**));
 364
 365 /* Sum up total data length for dynamic arraies (strings) */
 366 static nokprobe_inline int
 367 __get_data_size(struct trace_probe *tp, struct pt_regs *regs)
 368 {
 369         int i, ret = 0;
 370         u32 len;
 371
 372         for (i = 0; i < tp->nr_args; i++)
 373                 if (unlikely(tp->args[i].fetch_size.fn)) {
 374                         call_fetch(&tp->args[i].fetch_size, regs, &len);
 375                         ret += len;
 376                 }
 377
 378         return ret;
 379 }
 380
 381 /* Store the value of each argument */
 382 static nokprobe_inline void
 383 store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs,
 384                  u8 *data, int maxlen)
 385 {
 386         int i;
 387         u32 end = tp->size;
 388         u32 *dl;        /* Data (relative) location */
 389
 390         for (i = 0; i < tp->nr_args; i++) {
 391                 if (unlikely(tp->args[i].fetch_size.fn)) {
 392                         /*
 393                          * First, we set the relative location and
 394                          * maximum data length to *dl
 395                          */
 396                         dl = (u32 *)(data + tp->args[i].offset);
 397                         *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
 398                         /* Then try to fetch string or dynamic array data */
 399                         call_fetch(&tp->args[i].fetch, regs, dl);
 400                         /* Reduce maximum length */
 401                         end += get_rloc_len(*dl);
 402                         maxlen -= get_rloc_len(*dl);
 403                         /* Trick here, convert data_rloc to data_loc */
 404                         *dl = convert_rloc_to_loc(*dl,
 405                                  ent_size + tp->args[i].offset);
 406                 } else
 407                         /* Just fetching data normally */
 408                         call_fetch(&tp->args[i].fetch, regs,
 409                                    data + tp->args[i].offset);
 410         }
 411 }
 412
 413 extern int set_print_fmt(struct trace_probe *tp, bool is_return);