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_memory,
 106         FETCH_MTD_symbol,
 107         FETCH_MTD_deref,
 108         FETCH_MTD_bitfield,
 109         FETCH_MTD_file_offset,
 110         FETCH_MTD_END,
 111 };
 112
 113 /* Fetch type information table */
 114 struct fetch_type {
 115         const char              *name;          /* Name of type */
 116         size_t                  size;           /* Byte size of type */
 117         int                     is_signed;      /* Signed flag */
 118         print_type_func_t       print;          /* Print functions */
 119         const char              *fmt;           /* Fromat string */
 120         const char              *fmttype;       /* Name in format file */
 121         /* Fetch functions */
 122         fetch_func_t            fetch[FETCH_MTD_END];
 123 };
 124
 125 struct fetch_param {
 126         fetch_func_t            fn;
 127         void                    *data;
 128 };
 129
 130 /* For defining macros, define string/string_size types */
 131 typedef u32 string;
 132 typedef u32 string_size;
 133
 134 #define PRINT_TYPE_FUNC_NAME(type)      print_type_##type
 135 #define PRINT_TYPE_FMT_NAME(type)       print_type_format_##type
 136
 137 /* Printing  in basic type function template */
 138 #define DECLARE_BASIC_PRINT_TYPE_FUNC(type)                             \
 139 int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name,   \
 140                                 void *data, void *ent);                 \
 141 extern const char PRINT_TYPE_FMT_NAME(type)[]
 142
 143 DECLARE_BASIC_PRINT_TYPE_FUNC(u8);
 144 DECLARE_BASIC_PRINT_TYPE_FUNC(u16);
 145 DECLARE_BASIC_PRINT_TYPE_FUNC(u32);
 146 DECLARE_BASIC_PRINT_TYPE_FUNC(u64);
 147 DECLARE_BASIC_PRINT_TYPE_FUNC(s8);
 148 DECLARE_BASIC_PRINT_TYPE_FUNC(s16);
 149 DECLARE_BASIC_PRINT_TYPE_FUNC(s32);
 150 DECLARE_BASIC_PRINT_TYPE_FUNC(s64);
 151 DECLARE_BASIC_PRINT_TYPE_FUNC(string);
 152
 153 #define FETCH_FUNC_NAME(method, type)   fetch_##method##_##type
 154
 155 /* Declare macro for basic types */
 156 #define DECLARE_FETCH_FUNC(method, type)                                \
 157 extern void FETCH_FUNC_NAME(method, type)(struct pt_regs *regs,         \
 158                                           void *data, void *dest)
 159
 160 #define DECLARE_BASIC_FETCH_FUNCS(method)       \
 161 DECLARE_FETCH_FUNC(method, u8);                 \
 162 DECLARE_FETCH_FUNC(method, u16);                \
 163 DECLARE_FETCH_FUNC(method, u32);                \
 164 DECLARE_FETCH_FUNC(method, u64)
 165
 166 DECLARE_BASIC_FETCH_FUNCS(reg);
 167 #define fetch_reg_string                        NULL
 168 #define fetch_reg_string_size                   NULL
 169
 170 DECLARE_BASIC_FETCH_FUNCS(retval);
 171 #define fetch_retval_string                     NULL
 172 #define fetch_retval_string_size                NULL
 173
 174 DECLARE_BASIC_FETCH_FUNCS(symbol);
 175 DECLARE_FETCH_FUNC(symbol, string);
 176 DECLARE_FETCH_FUNC(symbol, string_size);
 177
 178 DECLARE_BASIC_FETCH_FUNCS(deref);
 179 DECLARE_FETCH_FUNC(deref, string);
 180 DECLARE_FETCH_FUNC(deref, string_size);
 181
 182 DECLARE_BASIC_FETCH_FUNCS(bitfield);
 183 #define fetch_bitfield_string                   NULL
 184 #define fetch_bitfield_string_size              NULL
 185
 186 /*
 187  * Define macro for basic types - we don't need to define s* types, because
 188  * we have to care only about bitwidth at recording time.
 189  */
 190 #define DEFINE_BASIC_FETCH_FUNCS(method) \
 191 DEFINE_FETCH_##method(u8)               \
 192 DEFINE_FETCH_##method(u16)              \
 193 DEFINE_FETCH_##method(u32)              \
 194 DEFINE_FETCH_##method(u64)
 195
 196 /* Default (unsigned long) fetch type */
 197 #define __DEFAULT_FETCH_TYPE(t) u##t
 198 #define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
 199 #define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
 200 #define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
 201
 202 #define ASSIGN_FETCH_FUNC(method, type) \
 203         [FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type)
 204
 205 #define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \
 206         {.name = _name,                         \
 207          .size = _size,                                 \
 208          .is_signed = sign,                             \
 209          .print = PRINT_TYPE_FUNC_NAME(ptype),          \
 210          .fmt = PRINT_TYPE_FMT_NAME(ptype),             \
 211          .fmttype = _fmttype,                           \
 212          .fetch = {                                     \
 213 ASSIGN_FETCH_FUNC(reg, ftype),                          \
 214 ASSIGN_FETCH_FUNC(stack, ftype),                        \
 215 ASSIGN_FETCH_FUNC(retval, ftype),                       \
 216 ASSIGN_FETCH_FUNC(memory, ftype),                       \
 217 ASSIGN_FETCH_FUNC(symbol, ftype),                       \
 218 ASSIGN_FETCH_FUNC(deref, ftype),                        \
 219 ASSIGN_FETCH_FUNC(bitfield, ftype),                     \
 220 ASSIGN_FETCH_FUNC(file_offset, ftype),                  \
 221           }                                             \
 222         }
 223
 224 #define ASSIGN_FETCH_TYPE(ptype, ftype, sign)                   \
 225         __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
 226
 227 #define ASSIGN_FETCH_TYPE_END {}
 228
 229 #define FETCH_TYPE_STRING       0
 230 #define FETCH_TYPE_STRSIZE      1
 231
 232 #ifdef CONFIG_KPROBE_EVENT
 233 struct symbol_cache;
 234 unsigned long update_symbol_cache(struct symbol_cache *sc);
 235 void free_symbol_cache(struct symbol_cache *sc);
 236 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset);
 237 #else
 238 /* uprobes do not support symbol fetch methods */
 239 #define fetch_symbol_u8                 NULL
 240 #define fetch_symbol_u16                NULL
 241 #define fetch_symbol_u32                NULL
 242 #define fetch_symbol_u64                NULL
 243 #define fetch_symbol_string             NULL
 244 #define fetch_symbol_string_size        NULL
 245
 246 struct symbol_cache {
 247 };
 248 static inline unsigned long __used update_symbol_cache(struct symbol_cache *sc)
 249 {
 250         return 0;
 251 }
 252
 253 static inline void __used free_symbol_cache(struct symbol_cache *sc)
 254 {
 255 }
 256
 257 static inline struct symbol_cache * __used
 258 alloc_symbol_cache(const char *sym, long offset)
 259 {
 260         return NULL;
 261 }
 262 #endif /* CONFIG_KPROBE_EVENT */
 263
 264 struct probe_arg {
 265         struct fetch_param      fetch;
 266         struct fetch_param      fetch_size;
 267         unsigned int            offset; /* Offset from argument entry */
 268         const char              *name;  /* Name of this argument */
 269         const char              *comm;  /* Command of this argument */
 270         const struct fetch_type *type;  /* Type of this argument */
 271 };
 272
 273 struct trace_probe {
 274         unsigned int                    flags;  /* For TP_FLAG_* */
 275         struct ftrace_event_class       class;
 276         struct ftrace_event_call        call;
 277         struct list_head                files;
 278         ssize_t                         size;   /* trace entry size */
 279         unsigned int                    nr_args;
 280         struct probe_arg                args[];
 281 };
 282
 283 struct event_file_link {
 284         struct ftrace_event_file        *file;
 285         struct list_head                list;
 286 };
 287
 288 static inline bool trace_probe_is_enabled(struct trace_probe *tp)
 289 {
 290         return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE));
 291 }
 292
 293 static inline bool trace_probe_is_registered(struct trace_probe *tp)
 294 {
 295         return !!(tp->flags & TP_FLAG_REGISTERED);
 296 }
 297
 298 static nokprobe_inline void call_fetch(struct fetch_param *fprm,
 299                                  struct pt_regs *regs, void *dest)
 300 {
 301         return fprm->fn(regs, fprm->data, dest);
 302 }
 303
 304 /* Check the name is good for event/group/fields */
 305 static inline int is_good_name(const char *name)
 306 {
 307         if (!isalpha(*name) && *name != '_')
 308                 return 0;
 309         while (*++name != '\0') {
 310                 if (!isalpha(*name) && !isdigit(*name) && *name != '_')
 311                         return 0;
 312         }
 313         return 1;
 314 }
 315
 316 static inline struct event_file_link *
 317 find_event_file_link(struct trace_probe *tp, struct ftrace_event_file *file)
 318 {
 319         struct event_file_link *link;
 320
 321         list_for_each_entry(link, &tp->files, list)
 322                 if (link->file == file)
 323                         return link;
 324
 325         return NULL;
 326 }
 327
 328 extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
 329                    struct probe_arg *parg, bool is_return, bool is_kprobe,
 330                    const struct fetch_type *ftbl);
 331
 332 extern int traceprobe_conflict_field_name(const char *name,
 333                                struct probe_arg *args, int narg);
 334
 335 extern void traceprobe_update_arg(struct probe_arg *arg);
 336 extern void traceprobe_free_probe_arg(struct probe_arg *arg);
 337
 338 extern int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset);
 339
 340 extern ssize_t traceprobe_probes_write(struct file *file,
 341                 const char __user *buffer, size_t count, loff_t *ppos,
 342                 int (*createfn)(int, char**));
 343
 344 extern int traceprobe_command(const char *buf, int (*createfn)(int, char**));
 345
 346 /* Sum up total data length for dynamic arraies (strings) */
 347 static nokprobe_inline int
 348 __get_data_size(struct trace_probe *tp, struct pt_regs *regs)
 349 {
 350         int i, ret = 0;
 351         u32 len;
 352
 353         for (i = 0; i < tp->nr_args; i++)
 354                 if (unlikely(tp->args[i].fetch_size.fn)) {
 355                         call_fetch(&tp->args[i].fetch_size, regs, &len);
 356                         ret += len;
 357                 }
 358
 359         return ret;
 360 }
 361
 362 /* Store the value of each argument */
 363 static nokprobe_inline void
 364 store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs,
 365                  u8 *data, int maxlen)
 366 {
 367         int i;
 368         u32 end = tp->size;
 369         u32 *dl;        /* Data (relative) location */
 370
 371         for (i = 0; i < tp->nr_args; i++) {
 372                 if (unlikely(tp->args[i].fetch_size.fn)) {
 373                         /*
 374                          * First, we set the relative location and
 375                          * maximum data length to *dl
 376                          */
 377                         dl = (u32 *)(data + tp->args[i].offset);
 378                         *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
 379                         /* Then try to fetch string or dynamic array data */
 380                         call_fetch(&tp->args[i].fetch, regs, dl);
 381                         /* Reduce maximum length */
 382                         end += get_rloc_len(*dl);
 383                         maxlen -= get_rloc_len(*dl);
 384                         /* Trick here, convert data_rloc to data_loc */
 385                         *dl = convert_rloc_to_loc(*dl,
 386                                  ent_size + tp->args[i].offset);
 387                 } else
 388                         /* Just fetching data normally */
 389                         call_fetch(&tp->args[i].fetch, regs,
 390                                    data + tp->args[i].offset);
 391         }
 392 }
 393
 394 extern int set_print_fmt(struct trace_probe *tp, bool is_return);