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