kernel/trace/trace_probe.h

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Common header file for probe-based Dynamic events.
   4  *
   5  * This code was copied from kernel/trace/trace_kprobe.h written by
   6  * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
   7  *
   8  * Updates to make this generic:
   9  * Copyright (C) IBM Corporation, 2010-2011
  10  * Author:     Srikar Dronamraju
  11  */
  12
  13 #include <linux/seq_file.h>
  14 #include <linux/slab.h>
  15 #include <linux/smp.h>
  16 #include <linux/tracefs.h>
  17 #include <linux/types.h>
  18 #include <linux/string.h>
  19 #include <linux/ctype.h>
  20 #include <linux/ptrace.h>
  21 #include <linux/perf_event.h>
  22 #include <linux/kprobes.h>
  23 #include <linux/stringify.h>
  24 #include <linux/limits.h>
  25 #include <linux/uaccess.h>
  26 #include <asm/bitsperlong.h>
  27
  28 #include "trace.h"
  29 #include "trace_output.h"
  30
  31 #define MAX_TRACE_ARGS          128
  32 #define MAX_ARGSTR_LEN          63
  33 #define MAX_STRING_SIZE         PATH_MAX
  34
  35 /* Reserved field names */
  36 #define FIELD_STRING_IP         "__probe_ip"
  37 #define FIELD_STRING_RETIP      "__probe_ret_ip"
  38 #define FIELD_STRING_FUNC       "__probe_func"
  39
  40 #undef DEFINE_FIELD
  41 #define DEFINE_FIELD(type, item, name, is_signed)                       \
  42         do {                                                            \
  43                 ret = trace_define_field(event_call, #type, name,       \
  44                                          offsetof(typeof(field), item), \
  45                                          sizeof(field.item), is_signed, \
  46                                          FILTER_OTHER);                 \
  47                 if (ret)                                                \
  48                         return ret;                                     \
  49         } while (0)
  50
  51
  52 /* Flags for trace_probe */
  53 #define TP_FLAG_TRACE           1
  54 #define TP_FLAG_PROFILE         2
  55 #define TP_FLAG_REGISTERED      4
  56
  57
  58 /* data_rloc: data relative location, compatible with u32 */
  59 #define make_data_rloc(len, roffs)      \
  60         (((u32)(len) << 16) | ((u32)(roffs) & 0xffff))
  61 #define get_rloc_len(dl)                ((u32)(dl) >> 16)
  62 #define get_rloc_offs(dl)               ((u32)(dl) & 0xffff)
  63
  64 /*
  65  * Convert data_rloc to data_loc:
  66  *  data_rloc stores the offset from data_rloc itself, but data_loc
  67  *  stores the offset from event entry.
  68  */
  69 #define convert_rloc_to_loc(dl, offs)   ((u32)(dl) + (offs))
  70
  71 static nokprobe_inline void *get_rloc_data(u32 *dl)
  72 {
  73         return (u8 *)dl + get_rloc_offs(*dl);
  74 }
  75
  76 /* For data_loc conversion */
  77 static nokprobe_inline void *get_loc_data(u32 *dl, void *ent)
  78 {
  79         return (u8 *)ent + get_rloc_offs(*dl);
  80 }
  81
  82 /* Data fetch function type */
  83 typedef void (*fetch_func_t)(struct pt_regs *, void *, void *);
  84 /* Printing function type */
  85 typedef int (*print_type_func_t)(struct trace_seq *, const char *, void *, void *);
  86
  87 /* Fetch types */
  88 enum {
  89         FETCH_MTD_reg = 0,
  90         FETCH_MTD_stack,
  91         FETCH_MTD_retval,
  92         FETCH_MTD_comm,
  93         FETCH_MTD_memory,
  94         FETCH_MTD_symbol,
  95         FETCH_MTD_deref,
  96         FETCH_MTD_bitfield,
  97         FETCH_MTD_file_offset,
  98         FETCH_MTD_END,
  99 };
 100
 101 /* Fetch type information table */
 102 struct fetch_type {
 103         const char              *name;          /* Name of type */
 104         size_t                  size;           /* Byte size of type */
 105         int                     is_signed;      /* Signed flag */
 106         print_type_func_t       print;          /* Print functions */
 107         const char              *fmt;           /* Fromat string */
 108         const char              *fmttype;       /* Name in format file */
 109         /* Fetch functions */
 110         fetch_func_t            fetch[FETCH_MTD_END];
 111 };
 112
 113 struct fetch_param {
 114         fetch_func_t            fn;
 115         void                    *data;
 116 };
 117
 118 /* For defining macros, define string/string_size types */
 119 typedef u32 string;
 120 typedef u32 string_size;
 121
 122 #define PRINT_TYPE_FUNC_NAME(type)      print_type_##type
 123 #define PRINT_TYPE_FMT_NAME(type)       print_type_format_##type
 124
 125 /* Printing  in basic type function template */
 126 #define DECLARE_BASIC_PRINT_TYPE_FUNC(type)                             \
 127 int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name,   \
 128                                 void *data, void *ent);                 \
 129 extern const char PRINT_TYPE_FMT_NAME(type)[]
 130
 131 DECLARE_BASIC_PRINT_TYPE_FUNC(u8);
 132 DECLARE_BASIC_PRINT_TYPE_FUNC(u16);
 133 DECLARE_BASIC_PRINT_TYPE_FUNC(u32);
 134 DECLARE_BASIC_PRINT_TYPE_FUNC(u64);
 135 DECLARE_BASIC_PRINT_TYPE_FUNC(s8);
 136 DECLARE_BASIC_PRINT_TYPE_FUNC(s16);
 137 DECLARE_BASIC_PRINT_TYPE_FUNC(s32);
 138 DECLARE_BASIC_PRINT_TYPE_FUNC(s64);
 139 DECLARE_BASIC_PRINT_TYPE_FUNC(x8);
 140 DECLARE_BASIC_PRINT_TYPE_FUNC(x16);
 141 DECLARE_BASIC_PRINT_TYPE_FUNC(x32);
 142 DECLARE_BASIC_PRINT_TYPE_FUNC(x64);
 143
 144 DECLARE_BASIC_PRINT_TYPE_FUNC(string);
 145
 146 #define FETCH_FUNC_NAME(method, type)   fetch_##method##_##type
 147
 148 /* Declare macro for basic types */
 149 #define DECLARE_FETCH_FUNC(method, type)                                \
 150 extern void FETCH_FUNC_NAME(method, type)(struct pt_regs *regs,         \
 151                                           void *data, void *dest)
 152
 153 #define DECLARE_BASIC_FETCH_FUNCS(method)       \
 154 DECLARE_FETCH_FUNC(method, u8);                 \
 155 DECLARE_FETCH_FUNC(method, u16);                \
 156 DECLARE_FETCH_FUNC(method, u32);                \
 157 DECLARE_FETCH_FUNC(method, u64)
 158
 159 DECLARE_BASIC_FETCH_FUNCS(reg);
 160 #define fetch_reg_string                        NULL
 161 #define fetch_reg_string_size                   NULL
 162
 163 DECLARE_BASIC_FETCH_FUNCS(retval);
 164 #define fetch_retval_string                     NULL
 165 #define fetch_retval_string_size                NULL
 166
 167 DECLARE_BASIC_FETCH_FUNCS(symbol);
 168 DECLARE_FETCH_FUNC(symbol, string);
 169 DECLARE_FETCH_FUNC(symbol, string_size);
 170
 171 DECLARE_BASIC_FETCH_FUNCS(deref);
 172 DECLARE_FETCH_FUNC(deref, string);
 173 DECLARE_FETCH_FUNC(deref, string_size);
 174
 175 DECLARE_BASIC_FETCH_FUNCS(bitfield);
 176 #define fetch_bitfield_string                   NULL
 177 #define fetch_bitfield_string_size              NULL
 178
 179 /* comm only makes sense as a string */
 180 #define fetch_comm_u8           NULL
 181 #define fetch_comm_u16          NULL
 182 #define fetch_comm_u32          NULL
 183 #define fetch_comm_u64          NULL
 184 DECLARE_FETCH_FUNC(comm, string);
 185 DECLARE_FETCH_FUNC(comm, string_size);
 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) x##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(comm, ftype),                         \
 218 ASSIGN_FETCH_FUNC(memory, ftype),                       \
 219 ASSIGN_FETCH_FUNC(symbol, ftype),                       \
 220 ASSIGN_FETCH_FUNC(deref, ftype),                        \
 221 ASSIGN_FETCH_FUNC(bitfield, ftype),                     \
 222 ASSIGN_FETCH_FUNC(file_offset, ftype),                  \
 223           }                                             \
 224         }
 225
 226 #define ASSIGN_FETCH_TYPE(ptype, ftype, sign)                   \
 227         __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
 228
 229 /* If ptype is an alias of atype, use this macro (show atype in format) */
 230 #define ASSIGN_FETCH_TYPE_ALIAS(ptype, atype, ftype, sign)              \
 231         __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #atype)
 232
 233 #define ASSIGN_FETCH_TYPE_END {}
 234
 235 #define FETCH_TYPE_STRING       0
 236 #define FETCH_TYPE_STRSIZE      1
 237
 238 #ifdef CONFIG_KPROBE_EVENTS
 239 struct symbol_cache;
 240 unsigned long update_symbol_cache(struct symbol_cache *sc);
 241 void free_symbol_cache(struct symbol_cache *sc);
 242 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset);
 243 bool trace_kprobe_on_func_entry(struct trace_event_call *call);
 244 bool trace_kprobe_error_injectable(struct trace_event_call *call);
 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
 271 static inline bool trace_kprobe_on_func_entry(struct trace_event_call *call)
 272 {
 273         return false;
 274 }
 275
 276 static inline bool trace_kprobe_error_injectable(struct trace_event_call *call)
 277 {
 278         return false;
 279 }
 280 #endif /* CONFIG_KPROBE_EVENTS */
 281
 282 struct probe_arg {
 283         struct fetch_param      fetch;
 284         struct fetch_param      fetch_size;
 285         unsigned int            offset; /* Offset from argument entry */
 286         const char              *name;  /* Name of this argument */
 287         const char              *comm;  /* Command of this argument */
 288         const struct fetch_type *type;  /* Type of this argument */
 289 };
 290
 291 struct trace_probe {
 292         unsigned int                    flags;  /* For TP_FLAG_* */
 293         struct trace_event_class        class;
 294         struct trace_event_call         call;
 295         struct list_head                files;
 296         ssize_t                         size;   /* trace entry size */
 297         unsigned int                    nr_args;
 298         struct probe_arg                args[];
 299 };
 300
 301 struct event_file_link {
 302         struct trace_event_file         *file;
 303         struct list_head                list;
 304 };
 305
 306 static inline bool trace_probe_is_enabled(struct trace_probe *tp)
 307 {
 308         return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE));
 309 }
 310
 311 static inline bool trace_probe_is_registered(struct trace_probe *tp)
 312 {
 313         return !!(tp->flags & TP_FLAG_REGISTERED);
 314 }
 315
 316 static nokprobe_inline void call_fetch(struct fetch_param *fprm,
 317                                  struct pt_regs *regs, void *dest)
 318 {
 319         return fprm->fn(regs, fprm->data, dest);
 320 }
 321
 322 /* Check the name is good for event/group/fields */
 323 static inline bool is_good_name(const char *name)
 324 {
 325         if (!isalpha(*name) && *name != '_')
 326                 return false;
 327         while (*++name != '\0') {
 328                 if (!isalpha(*name) && !isdigit(*name) && *name != '_')
 329                         return false;
 330         }
 331         return true;
 332 }
 333
 334 static inline struct event_file_link *
 335 find_event_file_link(struct trace_probe *tp, struct trace_event_file *file)
 336 {
 337         struct event_file_link *link;
 338
 339         list_for_each_entry(link, &tp->files, list)
 340                 if (link->file == file)
 341                         return link;
 342
 343         return NULL;
 344 }
 345
 346 extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
 347                    struct probe_arg *parg, bool is_return, bool is_kprobe,
 348                    const struct fetch_type *ftbl);
 349
 350 extern int traceprobe_conflict_field_name(const char *name,
 351                                struct probe_arg *args, int narg);
 352
 353 extern void traceprobe_update_arg(struct probe_arg *arg);
 354 extern void traceprobe_free_probe_arg(struct probe_arg *arg);
 355
 356 extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
 357
 358 /* Sum up total data length for dynamic arraies (strings) */
 359 static nokprobe_inline int
 360 __get_data_size(struct trace_probe *tp, struct pt_regs *regs)
 361 {
 362         int i, ret = 0;
 363         u32 len;
 364
 365         for (i = 0; i < tp->nr_args; i++)
 366                 if (unlikely(tp->args[i].fetch_size.fn)) {
 367                         call_fetch(&tp->args[i].fetch_size, regs, &len);
 368                         ret += len;
 369                 }
 370
 371         return ret;
 372 }
 373
 374 /* Store the value of each argument */
 375 static nokprobe_inline void
 376 store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs,
 377                  u8 *data, int maxlen)
 378 {
 379         int i;
 380         u32 end = tp->size;
 381         u32 *dl;        /* Data (relative) location */
 382
 383         for (i = 0; i < tp->nr_args; i++) {
 384                 if (unlikely(tp->args[i].fetch_size.fn)) {
 385                         /*
 386                          * First, we set the relative location and
 387                          * maximum data length to *dl
 388                          */
 389                         dl = (u32 *)(data + tp->args[i].offset);
 390                         *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
 391                         /* Then try to fetch string or dynamic array data */
 392                         call_fetch(&tp->args[i].fetch, regs, dl);
 393                         /* Reduce maximum length */
 394                         end += get_rloc_len(*dl);
 395                         maxlen -= get_rloc_len(*dl);
 396                         /* Trick here, convert data_rloc to data_loc */
 397                         *dl = convert_rloc_to_loc(*dl,
 398                                  ent_size + tp->args[i].offset);
 399                 } else
 400                         /* Just fetching data normally */
 401                         call_fetch(&tp->args[i].fetch, regs,
 402                                    data + tp->args[i].offset);
 403         }
 404 }
 405
 406 extern int set_print_fmt(struct trace_probe *tp, bool is_return);
 407
 408 #ifdef CONFIG_PERF_EVENTS
 409 extern struct trace_event_call *
 410 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
 411                           bool is_return);
 412 extern void destroy_local_trace_kprobe(struct trace_event_call *event_call);
 413
 414 extern struct trace_event_call *
 415 create_local_trace_uprobe(char *name, unsigned long offs, bool is_return);
 416 extern void destroy_local_trace_uprobe(struct trace_event_call *event_call);
 417 #endif