kernel/trace/trace_kprobe.c

   1 /*
   2  * Kprobes-based tracing events
   3  *
   4  * Created by Masami Hiramatsu <mhiramat@redhat.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/uaccess.h>
  22 #include <linux/kprobes.h>
  23 #include <linux/seq_file.h>
  24 #include <linux/slab.h>
  25 #include <linux/smp.h>
  26 #include <linux/debugfs.h>
  27 #include <linux/types.h>
  28 #include <linux/string.h>
  29 #include <linux/ctype.h>
  30 #include <linux/ptrace.h>
  31 #include <linux/perf_event.h>
  32 #include <linux/stringify.h>
  33 #include <linux/limits.h>
  34 #include <asm/bitsperlong.h>
  35
  36 #include "trace.h"
  37 #include "trace_output.h"
  38
  39 #define MAX_TRACE_ARGS 128
  40 #define MAX_ARGSTR_LEN 63
  41 #define MAX_EVENT_NAME_LEN 64
  42 #define MAX_STRING_SIZE PATH_MAX
  43 #define KPROBE_EVENT_SYSTEM "kprobes"
  44
  45 /* Reserved field names */
  46 #define FIELD_STRING_IP "__probe_ip"
  47 #define FIELD_STRING_RETIP "__probe_ret_ip"
  48 #define FIELD_STRING_FUNC "__probe_func"
  49
  50 const char *reserved_field_names[] = {
  51         "common_type",
  52         "common_flags",
  53         "common_preempt_count",
  54         "common_pid",
  55         "common_tgid",
  56         FIELD_STRING_IP,
  57         FIELD_STRING_RETIP,
  58         FIELD_STRING_FUNC,
  59 };
  60
  61 /* Printing function type */
  62 typedef int (*print_type_func_t)(struct trace_seq *, const char *, void *,
  63                                  void *);
  64 #define PRINT_TYPE_FUNC_NAME(type)      print_type_##type
  65 #define PRINT_TYPE_FMT_NAME(type)       print_type_format_##type
  66
  67 /* Printing  in basic type function template */
  68 #define DEFINE_BASIC_PRINT_TYPE_FUNC(type, fmt, cast)                   \
  69 static __kprobes int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s,    \
  70                                                 const char *name,       \
  71                                                 void *data, void *ent)\
  72 {                                                                       \
  73         return trace_seq_printf(s, " %s=" fmt, name, (cast)*(type *)data);\
  74 }                                                                       \
  75 static const char PRINT_TYPE_FMT_NAME(type)[] = fmt;
  76
  77 DEFINE_BASIC_PRINT_TYPE_FUNC(u8, "%x", unsigned int)
  78 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, "%x", unsigned int)
  79 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, "%lx", unsigned long)
  80 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, "%llx", unsigned long long)
  81 DEFINE_BASIC_PRINT_TYPE_FUNC(s8, "%d", int)
  82 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, "%d", int)
  83 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, "%ld", long)
  84 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, "%lld", long long)
  85
  86 /* data_rloc: data relative location, compatible with u32 */
  87 #define make_data_rloc(len, roffs)      \
  88         (((u32)(len) << 16) | ((u32)(roffs) & 0xffff))
  89 #define get_rloc_len(dl)        ((u32)(dl) >> 16)
  90 #define get_rloc_offs(dl)       ((u32)(dl) & 0xffff)
  91
  92 static inline void *get_rloc_data(u32 *dl)
  93 {
  94         return (u8 *)dl + get_rloc_offs(*dl);
  95 }
  96
  97 /* For data_loc conversion */
  98 static inline void *get_loc_data(u32 *dl, void *ent)
  99 {
 100         return (u8 *)ent + get_rloc_offs(*dl);
 101 }
 102
 103 /*
 104  * Convert data_rloc to data_loc:
 105  *  data_rloc stores the offset from data_rloc itself, but data_loc
 106  *  stores the offset from event entry.
 107  */
 108 #define convert_rloc_to_loc(dl, offs)   ((u32)(dl) + (offs))
 109
 110 /* For defining macros, define string/string_size types */
 111 typedef u32 string;
 112 typedef u32 string_size;
 113
 114 /* Print type function for string type */
 115 static __kprobes int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s,
 116                                                   const char *name,
 117                                                   void *data, void *ent)
 118 {
 119         int len = *(u32 *)data >> 16;
 120
 121         if (!len)
 122                 return trace_seq_printf(s, " %s=(fault)", name);
 123         else
 124                 return trace_seq_printf(s, " %s=\"%s\"", name,
 125                                         (const char *)get_loc_data(data, ent));
 126 }
 127 static const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
 128
 129 /* Data fetch function type */
 130 typedef void (*fetch_func_t)(struct pt_regs *, void *, void *);
 131
 132 struct fetch_param {
 133         fetch_func_t    fn;
 134         void *data;
 135 };
 136
 137 static __kprobes void call_fetch(struct fetch_param *fprm,
 138                                  struct pt_regs *regs, void *dest)
 139 {
 140         return fprm->fn(regs, fprm->data, dest);
 141 }
 142
 143 #define FETCH_FUNC_NAME(method, type)   fetch_##method##_##type
 144 /*
 145  * Define macro for basic types - we don't need to define s* types, because
 146  * we have to care only about bitwidth at recording time.
 147  */
 148 #define DEFINE_BASIC_FETCH_FUNCS(method) \
 149 DEFINE_FETCH_##method(u8)               \
 150 DEFINE_FETCH_##method(u16)              \
 151 DEFINE_FETCH_##method(u32)              \
 152 DEFINE_FETCH_##method(u64)
 153
 154 #define CHECK_FETCH_FUNCS(method, fn)                   \
 155         (((FETCH_FUNC_NAME(method, u8) == fn) ||        \
 156           (FETCH_FUNC_NAME(method, u16) == fn) ||       \
 157           (FETCH_FUNC_NAME(method, u32) == fn) ||       \
 158           (FETCH_FUNC_NAME(method, u64) == fn) ||       \
 159           (FETCH_FUNC_NAME(method, string) == fn) ||    \
 160           (FETCH_FUNC_NAME(method, string_size) == fn)) \
 161          && (fn != NULL))
 162
 163 /* Data fetch function templates */
 164 #define DEFINE_FETCH_reg(type)                                          \
 165 static __kprobes void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs,  \
 166                                         void *offset, void *dest)       \
 167 {                                                                       \
 168         *(type *)dest = (type)regs_get_register(regs,                   \
 169                                 (unsigned int)((unsigned long)offset)); \
 170 }
 171 DEFINE_BASIC_FETCH_FUNCS(reg)
 172 /* No string on the register */
 173 #define fetch_reg_string NULL
 174 #define fetch_reg_string_size NULL
 175
 176 #define DEFINE_FETCH_stack(type)                                        \
 177 static __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,\
 178                                           void *offset, void *dest)     \
 179 {                                                                       \
 180         *(type *)dest = (type)regs_get_kernel_stack_nth(regs,           \
 181                                 (unsigned int)((unsigned long)offset)); \
 182 }
 183 DEFINE_BASIC_FETCH_FUNCS(stack)
 184 /* No string on the stack entry */
 185 #define fetch_stack_string NULL
 186 #define fetch_stack_string_size NULL
 187
 188 #define DEFINE_FETCH_retval(type)                                       \
 189 static __kprobes void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs,\
 190                                           void *dummy, void *dest)      \
 191 {                                                                       \
 192         *(type *)dest = (type)regs_return_value(regs);                  \
 193 }
 194 DEFINE_BASIC_FETCH_FUNCS(retval)
 195 /* No string on the retval */
 196 #define fetch_retval_string NULL
 197 #define fetch_retval_string_size NULL
 198
 199 #define DEFINE_FETCH_memory(type)                                       \
 200 static __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,\
 201                                           void *addr, void *dest)       \
 202 {                                                                       \
 203         type retval;                                                    \
 204         if (probe_kernel_address(addr, retval))                         \
 205                 *(type *)dest = 0;                                      \
 206         else                                                            \
 207                 *(type *)dest = retval;                                 \
 208 }
 209 DEFINE_BASIC_FETCH_FUNCS(memory)
 210 /*
 211  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
 212  * length and relative data location.
 213  */
 214 static __kprobes void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
 215                                                       void *addr, void *dest)
 216 {
 217         long ret;
 218         int maxlen = get_rloc_len(*(u32 *)dest);
 219         u8 *dst = get_rloc_data(dest);
 220         u8 *src = addr;
 221         mm_segment_t old_fs = get_fs();
 222         if (!maxlen)
 223                 return;
 224         /*
 225          * Try to get string again, since the string can be changed while
 226          * probing.
 227          */
 228         set_fs(KERNEL_DS);
 229         pagefault_disable();
 230         do
 231                 ret = __copy_from_user_inatomic(dst++, src++, 1);
 232         while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen);
 233         dst[-1] = '\0';
 234         pagefault_enable();
 235         set_fs(old_fs);
 236
 237         if (ret < 0) {  /* Failed to fetch string */
 238                 ((u8 *)get_rloc_data(dest))[0] = '\0';
 239                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
 240         } else
 241                 *(u32 *)dest = make_data_rloc(src - (u8 *)addr,
 242                                               get_rloc_offs(*(u32 *)dest));
 243 }
 244 /* Return the length of string -- including null terminal byte */
 245 static __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
 246                                                         void *addr, void *dest)
 247 {
 248         int ret, len = 0;
 249         u8 c;
 250         mm_segment_t old_fs = get_fs();
 251
 252         set_fs(KERNEL_DS);
 253         pagefault_disable();
 254         do {
 255                 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
 256                 len++;
 257         } while (c && ret == 0 && len < MAX_STRING_SIZE);
 258         pagefault_enable();
 259         set_fs(old_fs);
 260
 261         if (ret < 0)    /* Failed to check the length */
 262                 *(u32 *)dest = 0;
 263         else
 264                 *(u32 *)dest = len;
 265 }
 266
 267 /* Memory fetching by symbol */
 268 struct symbol_cache {
 269         char *symbol;
 270         long offset;
 271         unsigned long addr;
 272 };
 273
 274 static unsigned long update_symbol_cache(struct symbol_cache *sc)
 275 {
 276         sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
 277         if (sc->addr)
 278                 sc->addr += sc->offset;
 279         return sc->addr;
 280 }
 281
 282 static void free_symbol_cache(struct symbol_cache *sc)
 283 {
 284         kfree(sc->symbol);
 285         kfree(sc);
 286 }
 287
 288 static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
 289 {
 290         struct symbol_cache *sc;
 291
 292         if (!sym || strlen(sym) == 0)
 293                 return NULL;
 294         sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
 295         if (!sc)
 296                 return NULL;
 297
 298         sc->symbol = kstrdup(sym, GFP_KERNEL);
 299         if (!sc->symbol) {
 300                 kfree(sc);
 301                 return NULL;
 302         }
 303         sc->offset = offset;
 304
 305         update_symbol_cache(sc);
 306         return sc;
 307 }
 308
 309 #define DEFINE_FETCH_symbol(type)                                       \
 310 static __kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs,\
 311                                           void *data, void *dest)       \
 312 {                                                                       \
 313         struct symbol_cache *sc = data;                                 \
 314         if (sc->addr)                                                   \
 315                 fetch_memory_##type(regs, (void *)sc->addr, dest);      \
 316         else                                                            \
 317                 *(type *)dest = 0;                                      \
 318 }
 319 DEFINE_BASIC_FETCH_FUNCS(symbol)
 320 DEFINE_FETCH_symbol(string)
 321 DEFINE_FETCH_symbol(string_size)
 322
 323 /* Dereference memory access function */
 324 struct deref_fetch_param {
 325         struct fetch_param orig;
 326         long offset;
 327 };
 328
 329 #define DEFINE_FETCH_deref(type)                                        \
 330 static __kprobes void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs,\
 331                                             void *data, void *dest)     \
 332 {                                                                       \
 333         struct deref_fetch_param *dprm = data;                          \
 334         unsigned long addr;                                             \
 335         call_fetch(&dprm->orig, regs, &addr);                           \
 336         if (addr) {                                                     \
 337                 addr += dprm->offset;                                   \
 338                 fetch_memory_##type(regs, (void *)addr, dest);          \
 339         } else                                                          \
 340                 *(type *)dest = 0;                                      \
 341 }
 342 DEFINE_BASIC_FETCH_FUNCS(deref)
 343 DEFINE_FETCH_deref(string)
 344 DEFINE_FETCH_deref(string_size)
 345
 346 static __kprobes void update_deref_fetch_param(struct deref_fetch_param *data)
 347 {
 348         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
 349                 update_deref_fetch_param(data->orig.data);
 350         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
 351                 update_symbol_cache(data->orig.data);
 352 }
 353
 354 static __kprobes void free_deref_fetch_param(struct deref_fetch_param *data)
 355 {
 356         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
 357                 free_deref_fetch_param(data->orig.data);
 358         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
 359                 free_symbol_cache(data->orig.data);
 360         kfree(data);
 361 }
 362
 363 /* Bitfield fetch function */
 364 struct bitfield_fetch_param {
 365         struct fetch_param orig;
 366         unsigned char hi_shift;
 367         unsigned char low_shift;
 368 };
 369
 370 #define DEFINE_FETCH_bitfield(type)                                     \
 371 static __kprobes void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs,\
 372                                             void *data, void *dest)     \
 373 {                                                                       \
 374         struct bitfield_fetch_param *bprm = data;                       \
 375         type buf = 0;                                                   \
 376         call_fetch(&bprm->orig, regs, &buf);                            \
 377         if (buf) {                                                      \
 378                 buf <<= bprm->hi_shift;                                 \
 379                 buf >>= bprm->low_shift;                                \
 380         }                                                               \
 381         *(type *)dest = buf;                                            \
 382 }
 383 DEFINE_BASIC_FETCH_FUNCS(bitfield)
 384 #define fetch_bitfield_string NULL
 385 #define fetch_bitfield_string_size NULL
 386
 387 static __kprobes void
 388 update_bitfield_fetch_param(struct bitfield_fetch_param *data)
 389 {
 390         /*
 391          * Don't check the bitfield itself, because this must be the
 392          * last fetch function.
 393          */
 394         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
 395                 update_deref_fetch_param(data->orig.data);
 396         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
 397                 update_symbol_cache(data->orig.data);
 398 }
 399
 400 static __kprobes void
 401 free_bitfield_fetch_param(struct bitfield_fetch_param *data)
 402 {
 403         /*
 404          * Don't check the bitfield itself, because this must be the
 405          * last fetch function.
 406          */
 407         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
 408                 free_deref_fetch_param(data->orig.data);
 409         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
 410                 free_symbol_cache(data->orig.data);
 411         kfree(data);
 412 }
 413
 414 /* Default (unsigned long) fetch type */
 415 #define __DEFAULT_FETCH_TYPE(t) u##t
 416 #define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
 417 #define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
 418 #define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
 419
 420 /* Fetch types */
 421 enum {
 422         FETCH_MTD_reg = 0,
 423         FETCH_MTD_stack,
 424         FETCH_MTD_retval,
 425         FETCH_MTD_memory,
 426         FETCH_MTD_symbol,
 427         FETCH_MTD_deref,
 428         FETCH_MTD_bitfield,
 429         FETCH_MTD_END,
 430 };
 431
 432 #define ASSIGN_FETCH_FUNC(method, type) \
 433         [FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type)
 434
 435 #define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \
 436         {.name = _name,                         \
 437          .size = _size,                                 \
 438          .is_signed = sign,                             \
 439          .print = PRINT_TYPE_FUNC_NAME(ptype),          \
 440          .fmt = PRINT_TYPE_FMT_NAME(ptype),             \
 441          .fmttype = _fmttype,                           \
 442          .fetch = {                                     \
 443 ASSIGN_FETCH_FUNC(reg, ftype),                          \
 444 ASSIGN_FETCH_FUNC(stack, ftype),                        \
 445 ASSIGN_FETCH_FUNC(retval, ftype),                       \
 446 ASSIGN_FETCH_FUNC(memory, ftype),                       \
 447 ASSIGN_FETCH_FUNC(symbol, ftype),                       \
 448 ASSIGN_FETCH_FUNC(deref, ftype),                        \
 449 ASSIGN_FETCH_FUNC(bitfield, ftype),                     \
 450           }                                             \
 451         }
 452
 453 #define ASSIGN_FETCH_TYPE(ptype, ftype, sign)                   \
 454         __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
 455
 456 #define FETCH_TYPE_STRING 0
 457 #define FETCH_TYPE_STRSIZE 1
 458
 459 /* Fetch type information table */
 460 static const struct fetch_type {
 461         const char      *name;          /* Name of type */
 462         size_t          size;           /* Byte size of type */
 463         int             is_signed;      /* Signed flag */
 464         print_type_func_t       print;  /* Print functions */
 465         const char      *fmt;           /* Fromat string */
 466         const char      *fmttype;       /* Name in format file */
 467         /* Fetch functions */
 468         fetch_func_t    fetch[FETCH_MTD_END];
 469 } fetch_type_table[] = {
 470         /* Special types */
 471         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
 472                                         sizeof(u32), 1, "__data_loc char[]"),
 473         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
 474                                         string_size, sizeof(u32), 0, "u32"),
 475         /* Basic types */
 476         ASSIGN_FETCH_TYPE(u8,  u8,  0),
 477         ASSIGN_FETCH_TYPE(u16, u16, 0),
 478         ASSIGN_FETCH_TYPE(u32, u32, 0),
 479         ASSIGN_FETCH_TYPE(u64, u64, 0),
 480         ASSIGN_FETCH_TYPE(s8,  u8,  1),
 481         ASSIGN_FETCH_TYPE(s16, u16, 1),
 482         ASSIGN_FETCH_TYPE(s32, u32, 1),
 483         ASSIGN_FETCH_TYPE(s64, u64, 1),
 484 };
 485
 486 static const struct fetch_type *find_fetch_type(const char *type)
 487 {
 488         int i;
 489
 490         if (!type)
 491                 type = DEFAULT_FETCH_TYPE_STR;
 492
 493         /* Special case: bitfield */
 494         if (*type == 'b') {
 495                 unsigned long bs;
 496                 type = strchr(type, '/');
 497                 if (!type)
 498                         goto fail;
 499                 type++;
 500                 if (strict_strtoul(type, 0, &bs))
 501                         goto fail;
 502                 switch (bs) {
 503                 case 8:
 504                         return find_fetch_type("u8");
 505                 case 16:
 506                         return find_fetch_type("u16");
 507                 case 32:
 508                         return find_fetch_type("u32");
 509                 case 64:
 510                         return find_fetch_type("u64");
 511                 default:
 512                         goto fail;
 513                 }
 514         }
 515
 516         for (i = 0; i < ARRAY_SIZE(fetch_type_table); i++)
 517                 if (strcmp(type, fetch_type_table[i].name) == 0)
 518                         return &fetch_type_table[i];
 519 fail:
 520         return NULL;
 521 }
 522
 523 /* Special function : only accept unsigned long */
 524 static __kprobes void fetch_stack_address(struct pt_regs *regs,
 525                                           void *dummy, void *dest)
 526 {
 527         *(unsigned long *)dest = kernel_stack_pointer(regs);
 528 }
 529
 530 static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
 531                                             fetch_func_t orig_fn)
 532 {
 533         int i;
 534
 535         if (type != &fetch_type_table[FETCH_TYPE_STRING])
 536                 return NULL;    /* Only string type needs size function */
 537         for (i = 0; i < FETCH_MTD_END; i++)
 538                 if (type->fetch[i] == orig_fn)
 539                         return fetch_type_table[FETCH_TYPE_STRSIZE].fetch[i];
 540
 541         WARN_ON(1);     /* This should not happen */
 542         return NULL;
 543 }
 544
 545 /**
 546  * Kprobe event core functions
 547  */
 548
 549 struct probe_arg {
 550         struct fetch_param      fetch;
 551         struct fetch_param      fetch_size;
 552         unsigned int            offset; /* Offset from argument entry */
 553         const char              *name;  /* Name of this argument */
 554         const char              *comm;  /* Command of this argument */
 555         const struct fetch_type *type;  /* Type of this argument */
 556 };
 557
 558 /* Flags for trace_probe */
 559 #define TP_FLAG_TRACE   1
 560 #define TP_FLAG_PROFILE 2
 561 #define TP_FLAG_REGISTERED 4
 562
 563 struct trace_probe {
 564         struct list_head        list;
 565         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
 566         unsigned long           nhit;
 567         unsigned int            flags;  /* For TP_FLAG_* */
 568         const char              *symbol;        /* symbol name */
 569         struct ftrace_event_class       class;
 570         struct ftrace_event_call        call;
 571         ssize_t                 size;           /* trace entry size */
 572         unsigned int            nr_args;
 573         struct probe_arg        args[];
 574 };
 575
 576 #define SIZEOF_TRACE_PROBE(n)                   \
 577         (offsetof(struct trace_probe, args) +   \
 578         (sizeof(struct probe_arg) * (n)))
 579
 580
 581 static __kprobes int trace_probe_is_return(struct trace_probe *tp)
 582 {
 583         return tp->rp.handler != NULL;
 584 }
 585
 586 static __kprobes const char *trace_probe_symbol(struct trace_probe *tp)
 587 {
 588         return tp->symbol ? tp->symbol : "unknown";
 589 }
 590
 591 static __kprobes unsigned long trace_probe_offset(struct trace_probe *tp)
 592 {
 593         return tp->rp.kp.offset;
 594 }
 595
 596 static __kprobes bool trace_probe_is_enabled(struct trace_probe *tp)
 597 {
 598         return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE));
 599 }
 600
 601 static __kprobes bool trace_probe_is_registered(struct trace_probe *tp)
 602 {
 603         return !!(tp->flags & TP_FLAG_REGISTERED);
 604 }
 605
 606 static __kprobes bool trace_probe_has_gone(struct trace_probe *tp)
 607 {
 608         return !!(kprobe_gone(&tp->rp.kp));
 609 }
 610
 611 static __kprobes bool trace_probe_within_module(struct trace_probe *tp,
 612                                                 struct module *mod)
 613 {
 614         int len = strlen(mod->name);
 615         const char *name = trace_probe_symbol(tp);
 616         return strncmp(mod->name, name, len) == 0 && name[len] == ':';
 617 }
 618
 619 static __kprobes bool trace_probe_is_on_module(struct trace_probe *tp)
 620 {
 621         return !!strchr(trace_probe_symbol(tp), ':');
 622 }
 623
 624 static int register_probe_event(struct trace_probe *tp);
 625 static void unregister_probe_event(struct trace_probe *tp);
 626
 627 static DEFINE_MUTEX(probe_lock);
 628 static LIST_HEAD(probe_list);
 629
 630 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 631 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 632                                 struct pt_regs *regs);
 633
 634 /* Check the name is good for event/group/fields */
 635 static int is_good_name(const char *name)
 636 {
 637         if (!isalpha(*name) && *name != '_')
 638                 return 0;
 639         while (*++name != '\0') {
 640                 if (!isalpha(*name) && !isdigit(*name) && *name != '_')
 641                         return 0;
 642         }
 643         return 1;
 644 }
 645
 646 /*
 647  * Allocate new trace_probe and initialize it (including kprobes).
 648  */
 649 static struct trace_probe *alloc_trace_probe(const char *group,
 650                                              const char *event,
 651                                              void *addr,
 652                                              const char *symbol,
 653                                              unsigned long offs,
 654                                              int nargs, int is_return)
 655 {
 656         struct trace_probe *tp;
 657         int ret = -ENOMEM;
 658
 659         tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
 660         if (!tp)
 661                 return ERR_PTR(ret);
 662
 663         if (symbol) {
 664                 tp->symbol = kstrdup(symbol, GFP_KERNEL);
 665                 if (!tp->symbol)
 666                         goto error;
 667                 tp->rp.kp.symbol_name = tp->symbol;
 668                 tp->rp.kp.offset = offs;
 669         } else
 670                 tp->rp.kp.addr = addr;
 671
 672         if (is_return)
 673                 tp->rp.handler = kretprobe_dispatcher;
 674         else
 675                 tp->rp.kp.pre_handler = kprobe_dispatcher;
 676
 677         if (!event || !is_good_name(event)) {
 678                 ret = -EINVAL;
 679                 goto error;
 680         }
 681
 682         tp->call.class = &tp->class;
 683         tp->call.name = kstrdup(event, GFP_KERNEL);
 684         if (!tp->call.name)
 685                 goto error;
 686
 687         if (!group || !is_good_name(group)) {
 688                 ret = -EINVAL;
 689                 goto error;
 690         }
 691
 692         tp->class.system = kstrdup(group, GFP_KERNEL);
 693         if (!tp->class.system)
 694                 goto error;
 695
 696         INIT_LIST_HEAD(&tp->list);
 697         return tp;
 698 error:
 699         kfree(tp->call.name);
 700         kfree(tp->symbol);
 701         kfree(tp);
 702         return ERR_PTR(ret);
 703 }
 704
 705 static void update_probe_arg(struct probe_arg *arg)
 706 {
 707         if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
 708                 update_bitfield_fetch_param(arg->fetch.data);
 709         else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
 710                 update_deref_fetch_param(arg->fetch.data);
 711         else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
 712                 update_symbol_cache(arg->fetch.data);
 713 }
 714
 715 static void free_probe_arg(struct probe_arg *arg)
 716 {
 717         if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
 718                 free_bitfield_fetch_param(arg->fetch.data);
 719         else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
 720                 free_deref_fetch_param(arg->fetch.data);
 721         else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
 722                 free_symbol_cache(arg->fetch.data);
 723         kfree(arg->name);
 724         kfree(arg->comm);
 725 }
 726
 727 static void free_trace_probe(struct trace_probe *tp)
 728 {
 729         int i;
 730
 731         for (i = 0; i < tp->nr_args; i++)
 732                 free_probe_arg(&tp->args[i]);
 733
 734         kfree(tp->call.class->system);
 735         kfree(tp->call.name);
 736         kfree(tp->symbol);
 737         kfree(tp);
 738 }
 739
 740 static struct trace_probe *find_trace_probe(const char *event,
 741                                             const char *group)
 742 {
 743         struct trace_probe *tp;
 744
 745         list_for_each_entry(tp, &probe_list, list)
 746                 if (strcmp(tp->call.name, event) == 0 &&
 747                     strcmp(tp->call.class->system, group) == 0)
 748                         return tp;
 749         return NULL;
 750 }
 751
 752 /* Enable trace_probe - @flag must be TP_FLAG_TRACE or TP_FLAG_PROFILE */
 753 static int enable_trace_probe(struct trace_probe *tp, int flag)
 754 {
 755         int ret = 0;
 756
 757         tp->flags |= flag;
 758         if (trace_probe_is_enabled(tp) && trace_probe_is_registered(tp) &&
 759             !trace_probe_has_gone(tp)) {
 760                 if (trace_probe_is_return(tp))
 761                         ret = enable_kretprobe(&tp->rp);
 762                 else
 763                         ret = enable_kprobe(&tp->rp.kp);
 764         }
 765
 766         return ret;
 767 }
 768
 769 /* Disable trace_probe - @flag must be TP_FLAG_TRACE or TP_FLAG_PROFILE */
 770 static void disable_trace_probe(struct trace_probe *tp, int flag)
 771 {
 772         tp->flags &= ~flag;
 773         if (!trace_probe_is_enabled(tp) && trace_probe_is_registered(tp)) {
 774                 if (trace_probe_is_return(tp))
 775                         disable_kretprobe(&tp->rp);
 776                 else
 777                         disable_kprobe(&tp->rp.kp);
 778         }
 779 }
 780
 781 /* Internal register function - just handle k*probes and flags */
 782 static int __register_trace_probe(struct trace_probe *tp)
 783 {
 784         int i, ret;
 785
 786         if (trace_probe_is_registered(tp))
 787                 return -EINVAL;
 788
 789         for (i = 0; i < tp->nr_args; i++)
 790                 update_probe_arg(&tp->args[i]);
 791
 792         /* Set/clear disabled flag according to tp->flag */
 793         if (trace_probe_is_enabled(tp))
 794                 tp->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
 795         else
 796                 tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 797
 798         if (trace_probe_is_return(tp))
 799                 ret = register_kretprobe(&tp->rp);
 800         else
 801                 ret = register_kprobe(&tp->rp.kp);
 802
 803         if (ret == 0)
 804                 tp->flags |= TP_FLAG_REGISTERED;
 805         else {
 806                 pr_warning("Could not insert probe at %s+%lu: %d\n",
 807                            trace_probe_symbol(tp), trace_probe_offset(tp), ret);
 808                 if (ret == -ENOENT && trace_probe_is_on_module(tp)) {
 809                         pr_warning("This probe might be able to register after"
 810                                    "target module is loaded. Continue.\n");
 811                         ret = 0;
 812                 } else if (ret == -EILSEQ) {
 813                         pr_warning("Probing address(0x%p) is not an "
 814                                    "instruction boundary.\n",
 815                                    tp->rp.kp.addr);
 816                         ret = -EINVAL;
 817                 }
 818         }
 819
 820         return ret;
 821 }
 822
 823 /* Internal unregister function - just handle k*probes and flags */
 824 static void __unregister_trace_probe(struct trace_probe *tp)
 825 {
 826         if (trace_probe_is_registered(tp)) {
 827                 if (trace_probe_is_return(tp))
 828                         unregister_kretprobe(&tp->rp);
 829                 else
 830                         unregister_kprobe(&tp->rp.kp);
 831                 tp->flags &= ~TP_FLAG_REGISTERED;
 832                 /* Cleanup kprobe for reuse */
 833                 if (tp->rp.kp.symbol_name)
 834                         tp->rp.kp.addr = NULL;
 835         }
 836 }
 837
 838 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
 839 static void unregister_trace_probe(struct trace_probe *tp)
 840 {
 841         __unregister_trace_probe(tp);
 842         list_del(&tp->list);
 843         unregister_probe_event(tp);
 844 }
 845
 846 /* Register a trace_probe and probe_event */
 847 static int register_trace_probe(struct trace_probe *tp)
 848 {
 849         struct trace_probe *old_tp;
 850         int ret;
 851
 852         mutex_lock(&probe_lock);
 853
 854         /* Delete old (same name) event if exist */
 855         old_tp = find_trace_probe(tp->call.name, tp->call.class->system);
 856         if (old_tp) {
 857                 unregister_trace_probe(old_tp);
 858                 free_trace_probe(old_tp);
 859         }
 860
 861         /* Register new event */
 862         ret = register_probe_event(tp);
 863         if (ret) {
 864                 pr_warning("Failed to register probe event(%d)\n", ret);
 865                 goto end;
 866         }
 867
 868         /* Register k*probe */
 869         ret = __register_trace_probe(tp);
 870         if (ret < 0)
 871                 unregister_probe_event(tp);
 872         else
 873                 list_add_tail(&tp->list, &probe_list);
 874
 875 end:
 876         mutex_unlock(&probe_lock);
 877         return ret;
 878 }
 879
 880 /* Module notifier call back, checking event on the module */
 881 static int trace_probe_module_callback(struct notifier_block *nb,
 882                                        unsigned long val, void *data)
 883 {
 884         struct module *mod = data;
 885         struct trace_probe *tp;
 886         int ret;
 887
 888         if (val != MODULE_STATE_COMING)
 889                 return NOTIFY_DONE;
 890
 891         /* Update probes on coming module */
 892         mutex_lock(&probe_lock);
 893         list_for_each_entry(tp, &probe_list, list) {
 894                 if (trace_probe_within_module(tp, mod)) {
 895                         __unregister_trace_probe(tp);
 896                         ret = __register_trace_probe(tp);
 897                         if (ret)
 898                                 pr_warning("Failed to re-register probe %s on"
 899                                            "%s: %d\n",
 900                                            tp->call.name, mod->name, ret);
 901                 }
 902         }
 903         mutex_unlock(&probe_lock);
 904
 905         return NOTIFY_DONE;
 906 }
 907
 908 static struct notifier_block trace_probe_module_nb = {
 909         .notifier_call = trace_probe_module_callback,
 910         .priority = 1   /* Invoked after kprobe module callback */
 911 };
 912
 913 /* Split symbol and offset. */
 914 static int split_symbol_offset(char *symbol, unsigned long *offset)
 915 {
 916         char *tmp;
 917         int ret;
 918
 919         if (!offset)
 920                 return -EINVAL;
 921
 922         tmp = strchr(symbol, '+');
 923         if (tmp) {
 924                 /* skip sign because strict_strtol doesn't accept '+' */
 925                 ret = strict_strtoul(tmp + 1, 0, offset);
 926                 if (ret)
 927                         return ret;
 928                 *tmp = '\0';
 929         } else
 930                 *offset = 0;
 931         return 0;
 932 }
 933
 934 #define PARAM_MAX_ARGS 16
 935 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 936
 937 static int parse_probe_vars(char *arg, const struct fetch_type *t,
 938                             struct fetch_param *f, int is_return)
 939 {
 940         int ret = 0;
 941         unsigned long param;
 942
 943         if (strcmp(arg, "retval") == 0) {
 944                 if (is_return)
 945                         f->fn = t->fetch[FETCH_MTD_retval];
 946                 else
 947                         ret = -EINVAL;
 948         } else if (strncmp(arg, "stack", 5) == 0) {
 949                 if (arg[5] == '\0') {
 950                         if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0)
 951                                 f->fn = fetch_stack_address;
 952                         else
 953                                 ret = -EINVAL;
 954                 } else if (isdigit(arg[5])) {
 955                         ret = strict_strtoul(arg + 5, 10, &param);
 956                         if (ret || param > PARAM_MAX_STACK)
 957                                 ret = -EINVAL;
 958                         else {
 959                                 f->fn = t->fetch[FETCH_MTD_stack];
 960                                 f->data = (void *)param;
 961                         }
 962                 } else
 963                         ret = -EINVAL;
 964         } else
 965                 ret = -EINVAL;
 966         return ret;
 967 }
 968
 969 /* Recursive argument parser */
 970 static int __parse_probe_arg(char *arg, const struct fetch_type *t,
 971                              struct fetch_param *f, int is_return)
 972 {
 973         int ret = 0;
 974         unsigned long param;
 975         long offset;
 976         char *tmp;
 977
 978         switch (arg[0]) {
 979         case '$':
 980                 ret = parse_probe_vars(arg + 1, t, f, is_return);
 981                 break;
 982         case '%':       /* named register */
 983                 ret = regs_query_register_offset(arg + 1);
 984                 if (ret >= 0) {
 985                         f->fn = t->fetch[FETCH_MTD_reg];
 986                         f->data = (void *)(unsigned long)ret;
 987                         ret = 0;
 988                 }
 989                 break;
 990         case '@':       /* memory or symbol */
 991                 if (isdigit(arg[1])) {
 992                         ret = strict_strtoul(arg + 1, 0, &param);
 993                         if (ret)
 994                                 break;
 995                         f->fn = t->fetch[FETCH_MTD_memory];
 996                         f->data = (void *)param;
 997                 } else {
 998                         ret = split_symbol_offset(arg + 1, &offset);
 999                         if (ret)
1000                                 break;
1001                         f->data = alloc_symbol_cache(arg + 1, offset);
1002                         if (f->data)
1003                                 f->fn = t->fetch[FETCH_MTD_symbol];
1004                 }
1005                 break;
1006         case '+':       /* deref memory */
1007                 arg++;  /* Skip '+', because strict_strtol() rejects it. */
1008         case '-':
1009                 tmp = strchr(arg, '(');
1010                 if (!tmp)
1011                         break;
1012                 *tmp = '\0';
1013                 ret = strict_strtol(arg, 0, &offset);
1014                 if (ret)
1015                         break;
1016                 arg = tmp + 1;
1017                 tmp = strrchr(arg, ')');
1018                 if (tmp) {
1019                         struct deref_fetch_param *dprm;
1020                         const struct fetch_type *t2 = find_fetch_type(NULL);
1021                         *tmp = '\0';
1022                         dprm = kzalloc(sizeof(struct deref_fetch_param),
1023                                        GFP_KERNEL);
1024                         if (!dprm)
1025                                 return -ENOMEM;
1026                         dprm->offset = offset;
1027                         ret = __parse_probe_arg(arg, t2, &dprm->orig,
1028                                                 is_return);
1029                         if (ret)
1030                                 kfree(dprm);
1031                         else {
1032                                 f->fn = t->fetch[FETCH_MTD_deref];
1033                                 f->data = (void *)dprm;
1034                         }
1035                 }
1036                 break;
1037         }
1038         if (!ret && !f->fn) {   /* Parsed, but do not find fetch method */
1039                 pr_info("%s type has no corresponding fetch method.\n",
1040                         t->name);
1041                 ret = -EINVAL;
1042         }
1043         return ret;
1044 }
1045
1046 #define BYTES_TO_BITS(nb)       ((BITS_PER_LONG * (nb)) / sizeof(long))
1047
1048 /* Bitfield type needs to be parsed into a fetch function */
1049 static int __parse_bitfield_probe_arg(const char *bf,
1050                                       const struct fetch_type *t,
1051                                       struct fetch_param *f)
1052 {
1053         struct bitfield_fetch_param *bprm;
1054         unsigned long bw, bo;
1055         char *tail;
1056
1057         if (*bf != 'b')
1058                 return 0;
1059
1060         bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
1061         if (!bprm)
1062                 return -ENOMEM;
1063         bprm->orig = *f;
1064         f->fn = t->fetch[FETCH_MTD_bitfield];
1065         f->data = (void *)bprm;
1066
1067         bw = simple_strtoul(bf + 1, &tail, 0);  /* Use simple one */
1068         if (bw == 0 || *tail != '@')
1069                 return -EINVAL;
1070
1071         bf = tail + 1;
1072         bo = simple_strtoul(bf, &tail, 0);
1073         if (tail == bf || *tail != '/')
1074                 return -EINVAL;
1075
1076         bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
1077         bprm->low_shift = bprm->hi_shift + bo;
1078         return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
1079 }
1080
1081 /* String length checking wrapper */
1082 static int parse_probe_arg(char *arg, struct trace_probe *tp,
1083                            struct probe_arg *parg, int is_return)
1084 {
1085         const char *t;
1086         int ret;
1087
1088         if (strlen(arg) > MAX_ARGSTR_LEN) {
1089                 pr_info("Argument is too long.: %s\n",  arg);
1090                 return -ENOSPC;
1091         }
1092         parg->comm = kstrdup(arg, GFP_KERNEL);
1093         if (!parg->comm) {
1094                 pr_info("Failed to allocate memory for command '%s'.\n", arg);
1095                 return -ENOMEM;
1096         }
1097         t = strchr(parg->comm, ':');
1098         if (t) {
1099                 arg[t - parg->comm] = '\0';
1100                 t++;
1101         }
1102         parg->type = find_fetch_type(t);
1103         if (!parg->type) {
1104                 pr_info("Unsupported type: %s\n", t);
1105                 return -EINVAL;
1106         }
1107         parg->offset = tp->size;
1108         tp->size += parg->type->size;
1109         ret = __parse_probe_arg(arg, parg->type, &parg->fetch, is_return);
1110         if (ret >= 0 && t != NULL)
1111                 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
1112         if (ret >= 0) {
1113                 parg->fetch_size.fn = get_fetch_size_function(parg->type,
1114                                                               parg->fetch.fn);
1115                 parg->fetch_size.data = parg->fetch.data;
1116         }
1117         return ret;
1118 }
1119
1120 /* Return 1 if name is reserved or already used by another argument */
1121 static int conflict_field_name(const char *name,
1122                                struct probe_arg *args, int narg)
1123 {
1124         int i;
1125         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
1126                 if (strcmp(reserved_field_names[i], name) == 0)
1127                         return 1;
1128         for (i = 0; i < narg; i++)
1129                 if (strcmp(args[i].name, name) == 0)
1130                         return 1;
1131         return 0;
1132 }
1133
1134 static int create_trace_probe(int argc, char **argv)
1135 {
1136         /*
1137          * Argument syntax:
1138          *  - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
1139          *  - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
1140          * Fetch args:
1141          *  $retval     : fetch return value
1142          *  $stack      : fetch stack address
1143          *  $stackN     : fetch Nth of stack (N:0-)
1144          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
1145          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
1146          *  %REG        : fetch register REG
1147          * Dereferencing memory fetch:
1148          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
1149          * Alias name of args:
1150          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
1151          * Type of args:
1152          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
1153          */
1154         struct trace_probe *tp;
1155         int i, ret = 0;
1156         int is_return = 0, is_delete = 0;
1157         char *symbol = NULL, *event = NULL, *group = NULL;
1158         char *arg;
1159         unsigned long offset = 0;
1160         void *addr = NULL;
1161         char buf[MAX_EVENT_NAME_LEN];
1162
1163         /* argc must be >= 1 */
1164         if (argv[0][0] == 'p')
1165                 is_return = 0;
1166         else if (argv[0][0] == 'r')
1167                 is_return = 1;
1168         else if (argv[0][0] == '-')
1169                 is_delete = 1;
1170         else {
1171                 pr_info("Probe definition must be started with 'p', 'r' or"
1172                         " '-'.\n");
1173                 return -EINVAL;
1174         }
1175
1176         if (argv[0][1] == ':') {
1177                 event = &argv[0][2];
1178                 if (strchr(event, '/')) {
1179                         group = event;
1180                         event = strchr(group, '/') + 1;
1181                         event[-1] = '\0';
1182                         if (strlen(group) == 0) {
1183                                 pr_info("Group name is not specified\n");
1184                                 return -EINVAL;
1185                         }
1186                 }
1187                 if (strlen(event) == 0) {
1188                         pr_info("Event name is not specified\n");
1189                         return -EINVAL;
1190                 }
1191         }
1192         if (!group)
1193                 group = KPROBE_EVENT_SYSTEM;
1194
1195         if (is_delete) {
1196                 if (!event) {
1197                         pr_info("Delete command needs an event name.\n");
1198                         return -EINVAL;
1199                 }
1200                 mutex_lock(&probe_lock);
1201                 tp = find_trace_probe(event, group);
1202                 if (!tp) {
1203                         mutex_unlock(&probe_lock);
1204                         pr_info("Event %s/%s doesn't exist.\n", group, event);
1205                         return -ENOENT;
1206                 }
1207                 /* delete an event */
1208                 unregister_trace_probe(tp);
1209                 free_trace_probe(tp);
1210                 mutex_unlock(&probe_lock);
1211                 return 0;
1212         }
1213
1214         if (argc < 2) {
1215                 pr_info("Probe point is not specified.\n");
1216                 return -EINVAL;
1217         }
1218         if (isdigit(argv[1][0])) {
1219                 if (is_return) {
1220                         pr_info("Return probe point must be a symbol.\n");
1221                         return -EINVAL;
1222                 }
1223                 /* an address specified */
1224                 ret = strict_strtoul(&argv[1][0], 0, (unsigned long *)&addr);
1225                 if (ret) {
1226                         pr_info("Failed to parse address.\n");
1227                         return ret;
1228                 }
1229         } else {
1230                 /* a symbol specified */
1231                 symbol = argv[1];
1232                 /* TODO: support .init module functions */
1233                 ret = split_symbol_offset(symbol, &offset);
1234                 if (ret) {
1235                         pr_info("Failed to parse symbol.\n");
1236                         return ret;
1237                 }
1238                 if (offset && is_return) {
1239                         pr_info("Return probe must be used without offset.\n");
1240                         return -EINVAL;
1241                 }
1242         }
1243         argc -= 2; argv += 2;
1244
1245         /* setup a probe */
1246         if (!event) {
1247                 /* Make a new event name */
1248                 if (symbol)
1249                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
1250                                  is_return ? 'r' : 'p', symbol, offset);
1251                 else
1252                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
1253                                  is_return ? 'r' : 'p', addr);
1254                 event = buf;
1255         }
1256         tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
1257                                is_return);
1258         if (IS_ERR(tp)) {
1259                 pr_info("Failed to allocate trace_probe.(%d)\n",
1260                         (int)PTR_ERR(tp));
1261                 return PTR_ERR(tp);
1262         }
1263
1264         /* parse arguments */
1265         ret = 0;
1266         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
1267                 /* Increment count for freeing args in error case */
1268                 tp->nr_args++;
1269
1270                 /* Parse argument name */
1271                 arg = strchr(argv[i], '=');
1272                 if (arg) {
1273                         *arg++ = '\0';
1274                         tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
1275                 } else {
1276                         arg = argv[i];
1277                         /* If argument name is omitted, set "argN" */
1278                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
1279                         tp->args[i].name = kstrdup(buf, GFP_KERNEL);
1280                 }
1281
1282                 if (!tp->args[i].name) {
1283                         pr_info("Failed to allocate argument[%d] name.\n", i);
1284                         ret = -ENOMEM;
1285                         goto error;
1286                 }
1287
1288                 if (!is_good_name(tp->args[i].name)) {
1289                         pr_info("Invalid argument[%d] name: %s\n",
1290                                 i, tp->args[i].name);
1291                         ret = -EINVAL;
1292                         goto error;
1293                 }
1294
1295                 if (conflict_field_name(tp->args[i].name, tp->args, i)) {
1296                         pr_info("Argument[%d] name '%s' conflicts with "
1297                                 "another field.\n", i, argv[i]);
1298                         ret = -EINVAL;
1299                         goto error;
1300                 }
1301
1302                 /* Parse fetch argument */
1303                 ret = parse_probe_arg(arg, tp, &tp->args[i], is_return);
1304                 if (ret) {
1305                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
1306                         goto error;
1307                 }
1308         }
1309
1310         ret = register_trace_probe(tp);
1311         if (ret)
1312                 goto error;
1313         return 0;
1314
1315 error:
1316         free_trace_probe(tp);
1317         return ret;
1318 }
1319
1320 static void release_all_trace_probes(void)
1321 {
1322         struct trace_probe *tp;
1323
1324         mutex_lock(&probe_lock);
1325         /* TODO: Use batch unregistration */
1326         while (!list_empty(&probe_list)) {
1327                 tp = list_entry(probe_list.next, struct trace_probe, list);
1328                 unregister_trace_probe(tp);
1329                 free_trace_probe(tp);
1330         }
1331         mutex_unlock(&probe_lock);
1332 }
1333
1334 /* Probes listing interfaces */
1335 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
1336 {
1337         mutex_lock(&probe_lock);
1338         return seq_list_start(&probe_list, *pos);
1339 }
1340
1341 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
1342 {
1343         return seq_list_next(v, &probe_list, pos);
1344 }
1345
1346 static void probes_seq_stop(struct seq_file *m, void *v)
1347 {
1348         mutex_unlock(&probe_lock);
1349 }
1350
1351 static int probes_seq_show(struct seq_file *m, void *v)
1352 {
1353         struct trace_probe *tp = v;
1354         int i;
1355
1356         seq_printf(m, "%c", trace_probe_is_return(tp) ? 'r' : 'p');
1357         seq_printf(m, ":%s/%s", tp->call.class->system, tp->call.name);
1358
1359         if (!tp->symbol)
1360                 seq_printf(m, " 0x%p", tp->rp.kp.addr);
1361         else if (tp->rp.kp.offset)
1362                 seq_printf(m, " %s+%u", trace_probe_symbol(tp),
1363                            tp->rp.kp.offset);
1364         else
1365                 seq_printf(m, " %s", trace_probe_symbol(tp));
1366
1367         for (i = 0; i < tp->nr_args; i++)
1368                 seq_printf(m, " %s=%s", tp->args[i].name, tp->args[i].comm);
1369         seq_printf(m, "\n");
1370
1371         return 0;
1372 }
1373
1374 static const struct seq_operations probes_seq_op = {
1375         .start  = probes_seq_start,
1376         .next   = probes_seq_next,
1377         .stop   = probes_seq_stop,
1378         .show   = probes_seq_show
1379 };
1380
1381 static int probes_open(struct inode *inode, struct file *file)
1382 {
1383         if ((file->f_mode & FMODE_WRITE) &&
1384             (file->f_flags & O_TRUNC))
1385                 release_all_trace_probes();
1386
1387         return seq_open(file, &probes_seq_op);
1388 }
1389
1390 static int command_trace_probe(const char *buf)
1391 {
1392         char **argv;
1393         int argc = 0, ret = 0;
1394
1395         argv = argv_split(GFP_KERNEL, buf, &argc);
1396         if (!argv)
1397                 return -ENOMEM;
1398
1399         if (argc)
1400                 ret = create_trace_probe(argc, argv);
1401
1402         argv_free(argv);
1403         return ret;
1404 }
1405
1406 #define WRITE_BUFSIZE 4096
1407
1408 static ssize_t probes_write(struct file *file, const char __user *buffer,
1409                             size_t count, loff_t *ppos)
1410 {
1411         char *kbuf, *tmp;
1412         int ret;
1413         size_t done;
1414         size_t size;
1415
1416         kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
1417         if (!kbuf)
1418                 return -ENOMEM;
1419
1420         ret = done = 0;
1421         while (done < count) {
1422                 size = count - done;
1423                 if (size >= WRITE_BUFSIZE)
1424                         size = WRITE_BUFSIZE - 1;
1425                 if (copy_from_user(kbuf, buffer + done, size)) {
1426                         ret = -EFAULT;
1427                         goto out;
1428                 }
1429                 kbuf[size] = '\0';
1430                 tmp = strchr(kbuf, '\n');
1431                 if (tmp) {
1432                         *tmp = '\0';
1433                         size = tmp - kbuf + 1;
1434                 } else if (done + size < count) {
1435                         pr_warning("Line length is too long: "
1436                                    "Should be less than %d.", WRITE_BUFSIZE);
1437                         ret = -EINVAL;
1438                         goto out;
1439                 }
1440                 done += size;
1441                 /* Remove comments */
1442                 tmp = strchr(kbuf, '#');
1443                 if (tmp)
1444                         *tmp = '\0';
1445
1446                 ret = command_trace_probe(kbuf);
1447                 if (ret)
1448                         goto out;
1449         }
1450         ret = done;
1451 out:
1452         kfree(kbuf);
1453         return ret;
1454 }
1455
1456 static const struct file_operations kprobe_events_ops = {
1457         .owner          = THIS_MODULE,
1458         .open           = probes_open,
1459         .read           = seq_read,
1460         .llseek         = seq_lseek,
1461         .release        = seq_release,
1462         .write          = probes_write,
1463 };
1464
1465 /* Probes profiling interfaces */
1466 static int probes_profile_seq_show(struct seq_file *m, void *v)
1467 {
1468         struct trace_probe *tp = v;
1469
1470         seq_printf(m, "  %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
1471                    tp->rp.kp.nmissed);
1472
1473         return 0;
1474 }
1475
1476 static const struct seq_operations profile_seq_op = {
1477         .start  = probes_seq_start,
1478         .next   = probes_seq_next,
1479         .stop   = probes_seq_stop,
1480         .show   = probes_profile_seq_show
1481 };
1482
1483 static int profile_open(struct inode *inode, struct file *file)
1484 {
1485         return seq_open(file, &profile_seq_op);
1486 }
1487
1488 static const struct file_operations kprobe_profile_ops = {
1489         .owner          = THIS_MODULE,
1490         .open           = profile_open,
1491         .read           = seq_read,
1492         .llseek         = seq_lseek,
1493         .release        = seq_release,
1494 };
1495
1496 /* Sum up total data length for dynamic arraies (strings) */
1497 static __kprobes int __get_data_size(struct trace_probe *tp,
1498                                      struct pt_regs *regs)
1499 {
1500         int i, ret = 0;
1501         u32 len;
1502
1503         for (i = 0; i < tp->nr_args; i++)
1504                 if (unlikely(tp->args[i].fetch_size.fn)) {
1505                         call_fetch(&tp->args[i].fetch_size, regs, &len);
1506                         ret += len;
1507                 }
1508
1509         return ret;
1510 }
1511
1512 /* Store the value of each argument */
1513 static __kprobes void store_trace_args(int ent_size, struct trace_probe *tp,
1514                                        struct pt_regs *regs,
1515                                        u8 *data, int maxlen)
1516 {
1517         int i;
1518         u32 end = tp->size;
1519         u32 *dl;        /* Data (relative) location */
1520
1521         for (i = 0; i < tp->nr_args; i++) {
1522                 if (unlikely(tp->args[i].fetch_size.fn)) {
1523                         /*
1524                          * First, we set the relative location and
1525                          * maximum data length to *dl
1526                          */
1527                         dl = (u32 *)(data + tp->args[i].offset);
1528                         *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
1529                         /* Then try to fetch string or dynamic array data */
1530                         call_fetch(&tp->args[i].fetch, regs, dl);
1531                         /* Reduce maximum length */
1532                         end += get_rloc_len(*dl);
1533                         maxlen -= get_rloc_len(*dl);
1534                         /* Trick here, convert data_rloc to data_loc */
1535                         *dl = convert_rloc_to_loc(*dl,
1536                                  ent_size + tp->args[i].offset);
1537                 } else
1538                         /* Just fetching data normally */
1539                         call_fetch(&tp->args[i].fetch, regs,
1540                                    data + tp->args[i].offset);
1541         }
1542 }
1543
1544 /* Kprobe handler */
1545 static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
1546 {
1547         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1548         struct kprobe_trace_entry_head *entry;
1549         struct ring_buffer_event *event;
1550         struct ring_buffer *buffer;
1551         int size, dsize, pc;
1552         unsigned long irq_flags;
1553         struct ftrace_event_call *call = &tp->call;
1554
1555         tp->nhit++;
1556
1557         local_save_flags(irq_flags);
1558         pc = preempt_count();
1559
1560         dsize = __get_data_size(tp, regs);
1561         size = sizeof(*entry) + tp->size + dsize;
1562
1563         event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1564                                                   size, irq_flags, pc);
1565         if (!event)
1566                 return;
1567
1568         entry = ring_buffer_event_data(event);
1569         entry->ip = (unsigned long)kp->addr;
1570         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1571
1572         if (!filter_current_check_discard(buffer, call, entry, event))
1573                 trace_nowake_buffer_unlock_commit_regs(buffer, event,
1574                                                        irq_flags, pc, regs);
1575 }
1576
1577 /* Kretprobe handler */
1578 static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
1579                                           struct pt_regs *regs)
1580 {
1581         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1582         struct kretprobe_trace_entry_head *entry;
1583         struct ring_buffer_event *event;
1584         struct ring_buffer *buffer;
1585         int size, pc, dsize;
1586         unsigned long irq_flags;
1587         struct ftrace_event_call *call = &tp->call;
1588
1589         local_save_flags(irq_flags);
1590         pc = preempt_count();
1591
1592         dsize = __get_data_size(tp, regs);
1593         size = sizeof(*entry) + tp->size + dsize;
1594
1595         event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1596                                                   size, irq_flags, pc);
1597         if (!event)
1598                 return;
1599
1600         entry = ring_buffer_event_data(event);
1601         entry->func = (unsigned long)tp->rp.kp.addr;
1602         entry->ret_ip = (unsigned long)ri->ret_addr;
1603         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1604
1605         if (!filter_current_check_discard(buffer, call, entry, event))
1606                 trace_nowake_buffer_unlock_commit_regs(buffer, event,
1607                                                        irq_flags, pc, regs);
1608 }
1609
1610 /* Event entry printers */
1611 enum print_line_t
1612 print_kprobe_event(struct trace_iterator *iter, int flags,
1613                    struct trace_event *event)
1614 {
1615         struct kprobe_trace_entry_head *field;
1616         struct trace_seq *s = &iter->seq;
1617         struct trace_probe *tp;
1618         u8 *data;
1619         int i;
1620
1621         field = (struct kprobe_trace_entry_head *)iter->ent;
1622         tp = container_of(event, struct trace_probe, call.event);
1623
1624         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1625                 goto partial;
1626
1627         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1628                 goto partial;
1629
1630         if (!trace_seq_puts(s, ")"))
1631                 goto partial;
1632
1633         data = (u8 *)&field[1];
1634         for (i = 0; i < tp->nr_args; i++)
1635                 if (!tp->args[i].type->print(s, tp->args[i].name,
1636                                              data + tp->args[i].offset, field))
1637                         goto partial;
1638
1639         if (!trace_seq_puts(s, "\n"))
1640                 goto partial;
1641
1642         return TRACE_TYPE_HANDLED;
1643 partial:
1644         return TRACE_TYPE_PARTIAL_LINE;
1645 }
1646
1647 enum print_line_t
1648 print_kretprobe_event(struct trace_iterator *iter, int flags,
1649                       struct trace_event *event)
1650 {
1651         struct kretprobe_trace_entry_head *field;
1652         struct trace_seq *s = &iter->seq;
1653         struct trace_probe *tp;
1654         u8 *data;
1655         int i;
1656
1657         field = (struct kretprobe_trace_entry_head *)iter->ent;
1658         tp = container_of(event, struct trace_probe, call.event);
1659
1660         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1661                 goto partial;
1662
1663         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1664                 goto partial;
1665
1666         if (!trace_seq_puts(s, " <- "))
1667                 goto partial;
1668
1669         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1670                 goto partial;
1671
1672         if (!trace_seq_puts(s, ")"))
1673                 goto partial;
1674
1675         data = (u8 *)&field[1];
1676         for (i = 0; i < tp->nr_args; i++)
1677                 if (!tp->args[i].type->print(s, tp->args[i].name,
1678                                              data + tp->args[i].offset, field))
1679                         goto partial;
1680
1681         if (!trace_seq_puts(s, "\n"))
1682                 goto partial;
1683
1684         return TRACE_TYPE_HANDLED;
1685 partial:
1686         return TRACE_TYPE_PARTIAL_LINE;
1687 }
1688
1689 #undef DEFINE_FIELD
1690 #define DEFINE_FIELD(type, item, name, is_signed)                       \
1691         do {                                                            \
1692                 ret = trace_define_field(event_call, #type, name,       \
1693                                          offsetof(typeof(field), item), \
1694                                          sizeof(field.item), is_signed, \
1695                                          FILTER_OTHER);                 \
1696                 if (ret)                                                \
1697                         return ret;                                     \
1698         } while (0)
1699
1700 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1701 {
1702         int ret, i;
1703         struct kprobe_trace_entry_head field;
1704         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1705
1706         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1707         /* Set argument names as fields */
1708         for (i = 0; i < tp->nr_args; i++) {
1709                 ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1710                                          tp->args[i].name,
1711                                          sizeof(field) + tp->args[i].offset,
1712                                          tp->args[i].type->size,
1713                                          tp->args[i].type->is_signed,
1714                                          FILTER_OTHER);
1715                 if (ret)
1716                         return ret;
1717         }
1718         return 0;
1719 }
1720
1721 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1722 {
1723         int ret, i;
1724         struct kretprobe_trace_entry_head field;
1725         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1726
1727         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1728         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1729         /* Set argument names as fields */
1730         for (i = 0; i < tp->nr_args; i++) {
1731                 ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1732                                          tp->args[i].name,
1733                                          sizeof(field) + tp->args[i].offset,
1734                                          tp->args[i].type->size,
1735                                          tp->args[i].type->is_signed,
1736                                          FILTER_OTHER);
1737                 if (ret)
1738                         return ret;
1739         }
1740         return 0;
1741 }
1742
1743 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len)
1744 {
1745         int i;
1746         int pos = 0;
1747
1748         const char *fmt, *arg;
1749
1750         if (!trace_probe_is_return(tp)) {
1751                 fmt = "(%lx)";
1752                 arg = "REC->" FIELD_STRING_IP;
1753         } else {
1754                 fmt = "(%lx <- %lx)";
1755                 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1756         }
1757
1758         /* When len=0, we just calculate the needed length */
1759 #define LEN_OR_ZERO (len ? len - pos : 0)
1760
1761         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1762
1763         for (i = 0; i < tp->nr_args; i++) {
1764                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
1765                                 tp->args[i].name, tp->args[i].type->fmt);
1766         }
1767
1768         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
1769
1770         for (i = 0; i < tp->nr_args; i++) {
1771                 if (strcmp(tp->args[i].type->name, "string") == 0)
1772                         pos += snprintf(buf + pos, LEN_OR_ZERO,
1773                                         ", __get_str(%s)",
1774                                         tp->args[i].name);
1775                 else
1776                         pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
1777                                         tp->args[i].name);
1778         }
1779
1780 #undef LEN_OR_ZERO
1781
1782         /* return the length of print_fmt */
1783         return pos;
1784 }
1785
1786 static int set_print_fmt(struct trace_probe *tp)
1787 {
1788         int len;
1789         char *print_fmt;
1790
1791         /* First: called with 0 length to calculate the needed length */
1792         len = __set_print_fmt(tp, NULL, 0);
1793         print_fmt = kmalloc(len + 1, GFP_KERNEL);
1794         if (!print_fmt)
1795                 return -ENOMEM;
1796
1797         /* Second: actually write the @print_fmt */
1798         __set_print_fmt(tp, print_fmt, len + 1);
1799         tp->call.print_fmt = print_fmt;
1800
1801         return 0;
1802 }
1803
1804 #ifdef CONFIG_PERF_EVENTS
1805
1806 /* Kprobe profile handler */
1807 static __kprobes void kprobe_perf_func(struct kprobe *kp,
1808                                          struct pt_regs *regs)
1809 {
1810         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1811         struct ftrace_event_call *call = &tp->call;
1812         struct kprobe_trace_entry_head *entry;
1813         struct hlist_head *head;
1814         int size, __size, dsize;
1815         int rctx;
1816
1817         dsize = __get_data_size(tp, regs);
1818         __size = sizeof(*entry) + tp->size + dsize;
1819         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1820         size -= sizeof(u32);
1821         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1822                      "profile buffer not large enough"))
1823                 return;
1824
1825         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1826         if (!entry)
1827                 return;
1828
1829         entry->ip = (unsigned long)kp->addr;
1830         memset(&entry[1], 0, dsize);
1831         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1832
1833         head = this_cpu_ptr(call->perf_events);
1834         perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
1835 }
1836
1837 /* Kretprobe profile handler */
1838 static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
1839                                             struct pt_regs *regs)
1840 {
1841         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1842         struct ftrace_event_call *call = &tp->call;
1843         struct kretprobe_trace_entry_head *entry;
1844         struct hlist_head *head;
1845         int size, __size, dsize;
1846         int rctx;
1847
1848         dsize = __get_data_size(tp, regs);
1849         __size = sizeof(*entry) + tp->size + dsize;
1850         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1851         size -= sizeof(u32);
1852         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1853                      "profile buffer not large enough"))
1854                 return;
1855
1856         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1857         if (!entry)
1858                 return;
1859
1860         entry->func = (unsigned long)tp->rp.kp.addr;
1861         entry->ret_ip = (unsigned long)ri->ret_addr;
1862         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1863
1864         head = this_cpu_ptr(call->perf_events);
1865         perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1, regs, head);
1866 }
1867 #endif  /* CONFIG_PERF_EVENTS */
1868
1869 static __kprobes
1870 int kprobe_register(struct ftrace_event_call *event, enum trace_reg type)
1871 {
1872         struct trace_probe *tp = (struct trace_probe *)event->data;
1873
1874         switch (type) {
1875         case TRACE_REG_REGISTER:
1876                 return enable_trace_probe(tp, TP_FLAG_TRACE);
1877         case TRACE_REG_UNREGISTER:
1878                 disable_trace_probe(tp, TP_FLAG_TRACE);
1879                 return 0;
1880
1881 #ifdef CONFIG_PERF_EVENTS
1882         case TRACE_REG_PERF_REGISTER:
1883                 return enable_trace_probe(tp, TP_FLAG_PROFILE);
1884         case TRACE_REG_PERF_UNREGISTER:
1885                 disable_trace_probe(tp, TP_FLAG_PROFILE);
1886                 return 0;
1887 #endif
1888         }
1889         return 0;
1890 }
1891
1892 static __kprobes
1893 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1894 {
1895         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1896
1897         if (tp->flags & TP_FLAG_TRACE)
1898                 kprobe_trace_func(kp, regs);
1899 #ifdef CONFIG_PERF_EVENTS
1900         if (tp->flags & TP_FLAG_PROFILE)
1901                 kprobe_perf_func(kp, regs);
1902 #endif
1903         return 0;       /* We don't tweek kernel, so just return 0 */
1904 }
1905
1906 static __kprobes
1907 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1908 {
1909         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1910
1911         if (tp->flags & TP_FLAG_TRACE)
1912                 kretprobe_trace_func(ri, regs);
1913 #ifdef CONFIG_PERF_EVENTS
1914         if (tp->flags & TP_FLAG_PROFILE)
1915                 kretprobe_perf_func(ri, regs);
1916 #endif
1917         return 0;       /* We don't tweek kernel, so just return 0 */
1918 }
1919
1920 static struct trace_event_functions kretprobe_funcs = {
1921         .trace          = print_kretprobe_event
1922 };
1923
1924 static struct trace_event_functions kprobe_funcs = {
1925         .trace          = print_kprobe_event
1926 };
1927
1928 static int register_probe_event(struct trace_probe *tp)
1929 {
1930         struct ftrace_event_call *call = &tp->call;
1931         int ret;
1932
1933         /* Initialize ftrace_event_call */
1934         INIT_LIST_HEAD(&call->class->fields);
1935         if (trace_probe_is_return(tp)) {
1936                 call->event.funcs = &kretprobe_funcs;
1937                 call->class->define_fields = kretprobe_event_define_fields;
1938         } else {
1939                 call->event.funcs = &kprobe_funcs;
1940                 call->class->define_fields = kprobe_event_define_fields;
1941         }
1942         if (set_print_fmt(tp) < 0)
1943                 return -ENOMEM;
1944         ret = register_ftrace_event(&call->event);
1945         if (!ret) {
1946                 kfree(call->print_fmt);
1947                 return -ENODEV;
1948         }
1949         call->flags = 0;
1950         call->class->reg = kprobe_register;
1951         call->data = tp;
1952         ret = trace_add_event_call(call);
1953         if (ret) {
1954                 pr_info("Failed to register kprobe event: %s\n", call->name);
1955                 kfree(call->print_fmt);
1956                 unregister_ftrace_event(&call->event);
1957         }
1958         return ret;
1959 }
1960
1961 static void unregister_probe_event(struct trace_probe *tp)
1962 {
1963         /* tp->event is unregistered in trace_remove_event_call() */
1964         trace_remove_event_call(&tp->call);
1965         kfree(tp->call.print_fmt);
1966 }
1967
1968 /* Make a debugfs interface for controlling probe points */
1969 static __init int init_kprobe_trace(void)
1970 {
1971         struct dentry *d_tracer;
1972         struct dentry *entry;
1973
1974         if (register_module_notifier(&trace_probe_module_nb))
1975                 return -EINVAL;
1976
1977         d_tracer = tracing_init_dentry();
1978         if (!d_tracer)
1979                 return 0;
1980
1981         entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1982                                     NULL, &kprobe_events_ops);
1983
1984         /* Event list interface */
1985         if (!entry)
1986                 pr_warning("Could not create debugfs "
1987                            "'kprobe_events' entry\n");
1988
1989         /* Profile interface */
1990         entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1991                                     NULL, &kprobe_profile_ops);
1992
1993         if (!entry)
1994                 pr_warning("Could not create debugfs "
1995                            "'kprobe_profile' entry\n");
1996         return 0;
1997 }
1998 fs_initcall(init_kprobe_trace);
1999
2000
2001 #ifdef CONFIG_FTRACE_STARTUP_TEST
2002
2003 /*
2004  * The "__used" keeps gcc from removing the function symbol
2005  * from the kallsyms table.
2006  */
2007 static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
2008                                                int a4, int a5, int a6)
2009 {
2010         return a1 + a2 + a3 + a4 + a5 + a6;
2011 }
2012
2013 static __init int kprobe_trace_self_tests_init(void)
2014 {
2015         int ret, warn = 0;
2016         int (*target)(int, int, int, int, int, int);
2017         struct trace_probe *tp;
2018
2019         target = kprobe_trace_selftest_target;
2020
2021         pr_info("Testing kprobe tracing: ");
2022
2023         ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
2024                                   "$stack $stack0 +0($stack)");
2025         if (WARN_ON_ONCE(ret)) {
2026                 pr_warning("error on probing function entry.\n");
2027                 warn++;
2028         } else {
2029                 /* Enable trace point */
2030                 tp = find_trace_probe("testprobe", KPROBE_EVENT_SYSTEM);
2031                 if (WARN_ON_ONCE(tp == NULL)) {
2032                         pr_warning("error on getting new probe.\n");
2033                         warn++;
2034                 } else
2035                         enable_trace_probe(tp, TP_FLAG_TRACE);
2036         }
2037
2038         ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
2039                                   "$retval");
2040         if (WARN_ON_ONCE(ret)) {
2041                 pr_warning("error on probing function return.\n");
2042                 warn++;
2043         } else {
2044                 /* Enable trace point */
2045                 tp = find_trace_probe("testprobe2", KPROBE_EVENT_SYSTEM);
2046                 if (WARN_ON_ONCE(tp == NULL)) {
2047                         pr_warning("error on getting new probe.\n");
2048                         warn++;
2049                 } else
2050                         enable_trace_probe(tp, TP_FLAG_TRACE);
2051         }
2052
2053         if (warn)
2054                 goto end;
2055
2056         ret = target(1, 2, 3, 4, 5, 6);
2057
2058         ret = command_trace_probe("-:testprobe");
2059         if (WARN_ON_ONCE(ret)) {
2060                 pr_warning("error on deleting a probe.\n");
2061                 warn++;
2062         }
2063
2064         ret = command_trace_probe("-:testprobe2");
2065         if (WARN_ON_ONCE(ret)) {
2066                 pr_warning("error on deleting a probe.\n");
2067                 warn++;
2068         }
2069
2070 end:
2071         release_all_trace_probes();
2072         if (warn)
2073                 pr_cont("NG: Some tests are failed. Please check them.\n");
2074         else
2075                 pr_cont("OK\n");
2076         return 0;
2077 }
2078
2079 late_initcall(kprobe_trace_self_tests_init);
2080
2081 #endif