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 int unregister_trace_probe(struct trace_probe *tp)
 840 {
 841         /* Enabled event can not be unregistered */
 842         if (trace_probe_is_enabled(tp))
 843                 return -EBUSY;
 844
 845         __unregister_trace_probe(tp);
 846         list_del(&tp->list);
 847         unregister_probe_event(tp);
 848
 849         return 0;
 850 }
 851
 852 /* Register a trace_probe and probe_event */
 853 static int register_trace_probe(struct trace_probe *tp)
 854 {
 855         struct trace_probe *old_tp;
 856         int ret;
 857
 858         mutex_lock(&probe_lock);
 859
 860         /* Delete old (same name) event if exist */
 861         old_tp = find_trace_probe(tp->call.name, tp->call.class->system);
 862         if (old_tp) {
 863                 ret = unregister_trace_probe(old_tp);
 864                 if (ret < 0)
 865                         goto end;
 866                 free_trace_probe(old_tp);
 867         }
 868
 869         /* Register new event */
 870         ret = register_probe_event(tp);
 871         if (ret) {
 872                 pr_warning("Failed to register probe event(%d)\n", ret);
 873                 goto end;
 874         }
 875
 876         /* Register k*probe */
 877         ret = __register_trace_probe(tp);
 878         if (ret < 0)
 879                 unregister_probe_event(tp);
 880         else
 881                 list_add_tail(&tp->list, &probe_list);
 882
 883 end:
 884         mutex_unlock(&probe_lock);
 885         return ret;
 886 }
 887
 888 /* Module notifier call back, checking event on the module */
 889 static int trace_probe_module_callback(struct notifier_block *nb,
 890                                        unsigned long val, void *data)
 891 {
 892         struct module *mod = data;
 893         struct trace_probe *tp;
 894         int ret;
 895
 896         if (val != MODULE_STATE_COMING)
 897                 return NOTIFY_DONE;
 898
 899         /* Update probes on coming module */
 900         mutex_lock(&probe_lock);
 901         list_for_each_entry(tp, &probe_list, list) {
 902                 if (trace_probe_within_module(tp, mod)) {
 903                         /* Don't need to check busy - this should have gone. */
 904                         __unregister_trace_probe(tp);
 905                         ret = __register_trace_probe(tp);
 906                         if (ret)
 907                                 pr_warning("Failed to re-register probe %s on"
 908                                            "%s: %d\n",
 909                                            tp->call.name, mod->name, ret);
 910                 }
 911         }
 912         mutex_unlock(&probe_lock);
 913
 914         return NOTIFY_DONE;
 915 }
 916
 917 static struct notifier_block trace_probe_module_nb = {
 918         .notifier_call = trace_probe_module_callback,
 919         .priority = 1   /* Invoked after kprobe module callback */
 920 };
 921
 922 /* Split symbol and offset. */
 923 static int split_symbol_offset(char *symbol, unsigned long *offset)
 924 {
 925         char *tmp;
 926         int ret;
 927
 928         if (!offset)
 929                 return -EINVAL;
 930
 931         tmp = strchr(symbol, '+');
 932         if (tmp) {
 933                 /* skip sign because strict_strtol doesn't accept '+' */
 934                 ret = strict_strtoul(tmp + 1, 0, offset);
 935                 if (ret)
 936                         return ret;
 937                 *tmp = '\0';
 938         } else
 939                 *offset = 0;
 940         return 0;
 941 }
 942
 943 #define PARAM_MAX_ARGS 16
 944 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 945
 946 static int parse_probe_vars(char *arg, const struct fetch_type *t,
 947                             struct fetch_param *f, int is_return)
 948 {
 949         int ret = 0;
 950         unsigned long param;
 951
 952         if (strcmp(arg, "retval") == 0) {
 953                 if (is_return)
 954                         f->fn = t->fetch[FETCH_MTD_retval];
 955                 else
 956                         ret = -EINVAL;
 957         } else if (strncmp(arg, "stack", 5) == 0) {
 958                 if (arg[5] == '\0') {
 959                         if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0)
 960                                 f->fn = fetch_stack_address;
 961                         else
 962                                 ret = -EINVAL;
 963                 } else if (isdigit(arg[5])) {
 964                         ret = strict_strtoul(arg + 5, 10, &param);
 965                         if (ret || param > PARAM_MAX_STACK)
 966                                 ret = -EINVAL;
 967                         else {
 968                                 f->fn = t->fetch[FETCH_MTD_stack];
 969                                 f->data = (void *)param;
 970                         }
 971                 } else
 972                         ret = -EINVAL;
 973         } else
 974                 ret = -EINVAL;
 975         return ret;
 976 }
 977
 978 /* Recursive argument parser */
 979 static int __parse_probe_arg(char *arg, const struct fetch_type *t,
 980                              struct fetch_param *f, int is_return)
 981 {
 982         int ret = 0;
 983         unsigned long param;
 984         long offset;
 985         char *tmp;
 986
 987         switch (arg[0]) {
 988         case '$':
 989                 ret = parse_probe_vars(arg + 1, t, f, is_return);
 990                 break;
 991         case '%':       /* named register */
 992                 ret = regs_query_register_offset(arg + 1);
 993                 if (ret >= 0) {
 994                         f->fn = t->fetch[FETCH_MTD_reg];
 995                         f->data = (void *)(unsigned long)ret;
 996                         ret = 0;
 997                 }
 998                 break;
 999         case '@':       /* memory or symbol */
1000                 if (isdigit(arg[1])) {
1001                         ret = strict_strtoul(arg + 1, 0, &param);
1002                         if (ret)
1003                                 break;
1004                         f->fn = t->fetch[FETCH_MTD_memory];
1005                         f->data = (void *)param;
1006                 } else {
1007                         ret = split_symbol_offset(arg + 1, &offset);
1008                         if (ret)
1009                                 break;
1010                         f->data = alloc_symbol_cache(arg + 1, offset);
1011                         if (f->data)
1012                                 f->fn = t->fetch[FETCH_MTD_symbol];
1013                 }
1014                 break;
1015         case '+':       /* deref memory */
1016                 arg++;  /* Skip '+', because strict_strtol() rejects it. */
1017         case '-':
1018                 tmp = strchr(arg, '(');
1019                 if (!tmp)
1020                         break;
1021                 *tmp = '\0';
1022                 ret = strict_strtol(arg, 0, &offset);
1023                 if (ret)
1024                         break;
1025                 arg = tmp + 1;
1026                 tmp = strrchr(arg, ')');
1027                 if (tmp) {
1028                         struct deref_fetch_param *dprm;
1029                         const struct fetch_type *t2 = find_fetch_type(NULL);
1030                         *tmp = '\0';
1031                         dprm = kzalloc(sizeof(struct deref_fetch_param),
1032                                        GFP_KERNEL);
1033                         if (!dprm)
1034                                 return -ENOMEM;
1035                         dprm->offset = offset;
1036                         ret = __parse_probe_arg(arg, t2, &dprm->orig,
1037                                                 is_return);
1038                         if (ret)
1039                                 kfree(dprm);
1040                         else {
1041                                 f->fn = t->fetch[FETCH_MTD_deref];
1042                                 f->data = (void *)dprm;
1043                         }
1044                 }
1045                 break;
1046         }
1047         if (!ret && !f->fn) {   /* Parsed, but do not find fetch method */
1048                 pr_info("%s type has no corresponding fetch method.\n",
1049                         t->name);
1050                 ret = -EINVAL;
1051         }
1052         return ret;
1053 }
1054
1055 #define BYTES_TO_BITS(nb)       ((BITS_PER_LONG * (nb)) / sizeof(long))
1056
1057 /* Bitfield type needs to be parsed into a fetch function */
1058 static int __parse_bitfield_probe_arg(const char *bf,
1059                                       const struct fetch_type *t,
1060                                       struct fetch_param *f)
1061 {
1062         struct bitfield_fetch_param *bprm;
1063         unsigned long bw, bo;
1064         char *tail;
1065
1066         if (*bf != 'b')
1067                 return 0;
1068
1069         bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
1070         if (!bprm)
1071                 return -ENOMEM;
1072         bprm->orig = *f;
1073         f->fn = t->fetch[FETCH_MTD_bitfield];
1074         f->data = (void *)bprm;
1075
1076         bw = simple_strtoul(bf + 1, &tail, 0);  /* Use simple one */
1077         if (bw == 0 || *tail != '@')
1078                 return -EINVAL;
1079
1080         bf = tail + 1;
1081         bo = simple_strtoul(bf, &tail, 0);
1082         if (tail == bf || *tail != '/')
1083                 return -EINVAL;
1084
1085         bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
1086         bprm->low_shift = bprm->hi_shift + bo;
1087         return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
1088 }
1089
1090 /* String length checking wrapper */
1091 static int parse_probe_arg(char *arg, struct trace_probe *tp,
1092                            struct probe_arg *parg, int is_return)
1093 {
1094         const char *t;
1095         int ret;
1096
1097         if (strlen(arg) > MAX_ARGSTR_LEN) {
1098                 pr_info("Argument is too long.: %s\n",  arg);
1099                 return -ENOSPC;
1100         }
1101         parg->comm = kstrdup(arg, GFP_KERNEL);
1102         if (!parg->comm) {
1103                 pr_info("Failed to allocate memory for command '%s'.\n", arg);
1104                 return -ENOMEM;
1105         }
1106         t = strchr(parg->comm, ':');
1107         if (t) {
1108                 arg[t - parg->comm] = '\0';
1109                 t++;
1110         }
1111         parg->type = find_fetch_type(t);
1112         if (!parg->type) {
1113                 pr_info("Unsupported type: %s\n", t);
1114                 return -EINVAL;
1115         }
1116         parg->offset = tp->size;
1117         tp->size += parg->type->size;
1118         ret = __parse_probe_arg(arg, parg->type, &parg->fetch, is_return);
1119         if (ret >= 0 && t != NULL)
1120                 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
1121         if (ret >= 0) {
1122                 parg->fetch_size.fn = get_fetch_size_function(parg->type,
1123                                                               parg->fetch.fn);
1124                 parg->fetch_size.data = parg->fetch.data;
1125         }
1126         return ret;
1127 }
1128
1129 /* Return 1 if name is reserved or already used by another argument */
1130 static int conflict_field_name(const char *name,
1131                                struct probe_arg *args, int narg)
1132 {
1133         int i;
1134         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
1135                 if (strcmp(reserved_field_names[i], name) == 0)
1136                         return 1;
1137         for (i = 0; i < narg; i++)
1138                 if (strcmp(args[i].name, name) == 0)
1139                         return 1;
1140         return 0;
1141 }
1142
1143 static int create_trace_probe(int argc, char **argv)
1144 {
1145         /*
1146          * Argument syntax:
1147          *  - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
1148          *  - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
1149          * Fetch args:
1150          *  $retval     : fetch return value
1151          *  $stack      : fetch stack address
1152          *  $stackN     : fetch Nth of stack (N:0-)
1153          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
1154          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
1155          *  %REG        : fetch register REG
1156          * Dereferencing memory fetch:
1157          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
1158          * Alias name of args:
1159          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
1160          * Type of args:
1161          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
1162          */
1163         struct trace_probe *tp;
1164         int i, ret = 0;
1165         int is_return = 0, is_delete = 0;
1166         char *symbol = NULL, *event = NULL, *group = NULL;
1167         char *arg;
1168         unsigned long offset = 0;
1169         void *addr = NULL;
1170         char buf[MAX_EVENT_NAME_LEN];
1171
1172         /* argc must be >= 1 */
1173         if (argv[0][0] == 'p')
1174                 is_return = 0;
1175         else if (argv[0][0] == 'r')
1176                 is_return = 1;
1177         else if (argv[0][0] == '-')
1178                 is_delete = 1;
1179         else {
1180                 pr_info("Probe definition must be started with 'p', 'r' or"
1181                         " '-'.\n");
1182                 return -EINVAL;
1183         }
1184
1185         if (argv[0][1] == ':') {
1186                 event = &argv[0][2];
1187                 if (strchr(event, '/')) {
1188                         group = event;
1189                         event = strchr(group, '/') + 1;
1190                         event[-1] = '\0';
1191                         if (strlen(group) == 0) {
1192                                 pr_info("Group name is not specified\n");
1193                                 return -EINVAL;
1194                         }
1195                 }
1196                 if (strlen(event) == 0) {
1197                         pr_info("Event name is not specified\n");
1198                         return -EINVAL;
1199                 }
1200         }
1201         if (!group)
1202                 group = KPROBE_EVENT_SYSTEM;
1203
1204         if (is_delete) {
1205                 if (!event) {
1206                         pr_info("Delete command needs an event name.\n");
1207                         return -EINVAL;
1208                 }
1209                 mutex_lock(&probe_lock);
1210                 tp = find_trace_probe(event, group);
1211                 if (!tp) {
1212                         mutex_unlock(&probe_lock);
1213                         pr_info("Event %s/%s doesn't exist.\n", group, event);
1214                         return -ENOENT;
1215                 }
1216                 /* delete an event */
1217                 ret = unregister_trace_probe(tp);
1218                 if (ret == 0)
1219                         free_trace_probe(tp);
1220                 mutex_unlock(&probe_lock);
1221                 return ret;
1222         }
1223
1224         if (argc < 2) {
1225                 pr_info("Probe point is not specified.\n");
1226                 return -EINVAL;
1227         }
1228
1229         /* try to parse an address. if that fails, try to read the
1230          * input as a symbol. */
1231         if (!strict_strtoul(argv[1], 0, (unsigned long *)&addr)) {
1232                 if (is_return) {
1233                         pr_info("Return probe point must be a symbol.\n");
1234                         return -EINVAL;
1235                 }
1236         } else {
1237                 /* a symbol specified */
1238                 symbol = argv[1];
1239                 /* TODO: support .init module functions */
1240                 ret = split_symbol_offset(symbol, &offset);
1241                 if (ret) {
1242                         pr_info("Failed to parse either an address or a symbol.\n");
1243                         return ret;
1244                 }
1245                 if (offset && is_return) {
1246                         pr_info("Return probe must be used without offset.\n");
1247                         return -EINVAL;
1248                 }
1249         }
1250         argc -= 2; argv += 2;
1251
1252         /* setup a probe */
1253         if (!event) {
1254                 /* Make a new event name */
1255                 if (symbol)
1256                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
1257                                  is_return ? 'r' : 'p', symbol, offset);
1258                 else
1259                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
1260                                  is_return ? 'r' : 'p', addr);
1261                 event = buf;
1262         }
1263         tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
1264                                is_return);
1265         if (IS_ERR(tp)) {
1266                 pr_info("Failed to allocate trace_probe.(%d)\n",
1267                         (int)PTR_ERR(tp));
1268                 return PTR_ERR(tp);
1269         }
1270
1271         /* parse arguments */
1272         ret = 0;
1273         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
1274                 /* Increment count for freeing args in error case */
1275                 tp->nr_args++;
1276
1277                 /* Parse argument name */
1278                 arg = strchr(argv[i], '=');
1279                 if (arg) {
1280                         *arg++ = '\0';
1281                         tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
1282                 } else {
1283                         arg = argv[i];
1284                         /* If argument name is omitted, set "argN" */
1285                         snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
1286                         tp->args[i].name = kstrdup(buf, GFP_KERNEL);
1287                 }
1288
1289                 if (!tp->args[i].name) {
1290                         pr_info("Failed to allocate argument[%d] name.\n", i);
1291                         ret = -ENOMEM;
1292                         goto error;
1293                 }
1294
1295                 if (!is_good_name(tp->args[i].name)) {
1296                         pr_info("Invalid argument[%d] name: %s\n",
1297                                 i, tp->args[i].name);
1298                         ret = -EINVAL;
1299                         goto error;
1300                 }
1301
1302                 if (conflict_field_name(tp->args[i].name, tp->args, i)) {
1303                         pr_info("Argument[%d] name '%s' conflicts with "
1304                                 "another field.\n", i, argv[i]);
1305                         ret = -EINVAL;
1306                         goto error;
1307                 }
1308
1309                 /* Parse fetch argument */
1310                 ret = parse_probe_arg(arg, tp, &tp->args[i], is_return);
1311                 if (ret) {
1312                         pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
1313                         goto error;
1314                 }
1315         }
1316
1317         ret = register_trace_probe(tp);
1318         if (ret)
1319                 goto error;
1320         return 0;
1321
1322 error:
1323         free_trace_probe(tp);
1324         return ret;
1325 }
1326
1327 static int release_all_trace_probes(void)
1328 {
1329         struct trace_probe *tp;
1330         int ret = 0;
1331
1332         mutex_lock(&probe_lock);
1333         /* Ensure no probe is in use. */
1334         list_for_each_entry(tp, &probe_list, list)
1335                 if (trace_probe_is_enabled(tp)) {
1336                         ret = -EBUSY;
1337                         goto end;
1338                 }
1339         /* TODO: Use batch unregistration */
1340         while (!list_empty(&probe_list)) {
1341                 tp = list_entry(probe_list.next, struct trace_probe, list);
1342                 unregister_trace_probe(tp);
1343                 free_trace_probe(tp);
1344         }
1345
1346 end:
1347         mutex_unlock(&probe_lock);
1348
1349         return ret;
1350 }
1351
1352 /* Probes listing interfaces */
1353 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
1354 {
1355         mutex_lock(&probe_lock);
1356         return seq_list_start(&probe_list, *pos);
1357 }
1358
1359 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
1360 {
1361         return seq_list_next(v, &probe_list, pos);
1362 }
1363
1364 static void probes_seq_stop(struct seq_file *m, void *v)
1365 {
1366         mutex_unlock(&probe_lock);
1367 }
1368
1369 static int probes_seq_show(struct seq_file *m, void *v)
1370 {
1371         struct trace_probe *tp = v;
1372         int i;
1373
1374         seq_printf(m, "%c", trace_probe_is_return(tp) ? 'r' : 'p');
1375         seq_printf(m, ":%s/%s", tp->call.class->system, tp->call.name);
1376
1377         if (!tp->symbol)
1378                 seq_printf(m, " 0x%p", tp->rp.kp.addr);
1379         else if (tp->rp.kp.offset)
1380                 seq_printf(m, " %s+%u", trace_probe_symbol(tp),
1381                            tp->rp.kp.offset);
1382         else
1383                 seq_printf(m, " %s", trace_probe_symbol(tp));
1384
1385         for (i = 0; i < tp->nr_args; i++)
1386                 seq_printf(m, " %s=%s", tp->args[i].name, tp->args[i].comm);
1387         seq_printf(m, "\n");
1388
1389         return 0;
1390 }
1391
1392 static const struct seq_operations probes_seq_op = {
1393         .start  = probes_seq_start,
1394         .next   = probes_seq_next,
1395         .stop   = probes_seq_stop,
1396         .show   = probes_seq_show
1397 };
1398
1399 static int probes_open(struct inode *inode, struct file *file)
1400 {
1401         int ret;
1402
1403         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1404                 ret = release_all_trace_probes();
1405                 if (ret < 0)
1406                         return ret;
1407         }
1408
1409         return seq_open(file, &probes_seq_op);
1410 }
1411
1412 static int command_trace_probe(const char *buf)
1413 {
1414         char **argv;
1415         int argc = 0, ret = 0;
1416
1417         argv = argv_split(GFP_KERNEL, buf, &argc);
1418         if (!argv)
1419                 return -ENOMEM;
1420
1421         if (argc)
1422                 ret = create_trace_probe(argc, argv);
1423
1424         argv_free(argv);
1425         return ret;
1426 }
1427
1428 #define WRITE_BUFSIZE 4096
1429
1430 static ssize_t probes_write(struct file *file, const char __user *buffer,
1431                             size_t count, loff_t *ppos)
1432 {
1433         char *kbuf, *tmp;
1434         int ret;
1435         size_t done;
1436         size_t size;
1437
1438         kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
1439         if (!kbuf)
1440                 return -ENOMEM;
1441
1442         ret = done = 0;
1443         while (done < count) {
1444                 size = count - done;
1445                 if (size >= WRITE_BUFSIZE)
1446                         size = WRITE_BUFSIZE - 1;
1447                 if (copy_from_user(kbuf, buffer + done, size)) {
1448                         ret = -EFAULT;
1449                         goto out;
1450                 }
1451                 kbuf[size] = '\0';
1452                 tmp = strchr(kbuf, '\n');
1453                 if (tmp) {
1454                         *tmp = '\0';
1455                         size = tmp - kbuf + 1;
1456                 } else if (done + size < count) {
1457                         pr_warning("Line length is too long: "
1458                                    "Should be less than %d.", WRITE_BUFSIZE);
1459                         ret = -EINVAL;
1460                         goto out;
1461                 }
1462                 done += size;
1463                 /* Remove comments */
1464                 tmp = strchr(kbuf, '#');
1465                 if (tmp)
1466                         *tmp = '\0';
1467
1468                 ret = command_trace_probe(kbuf);
1469                 if (ret)
1470                         goto out;
1471         }
1472         ret = done;
1473 out:
1474         kfree(kbuf);
1475         return ret;
1476 }
1477
1478 static const struct file_operations kprobe_events_ops = {
1479         .owner          = THIS_MODULE,
1480         .open           = probes_open,
1481         .read           = seq_read,
1482         .llseek         = seq_lseek,
1483         .release        = seq_release,
1484         .write          = probes_write,
1485 };
1486
1487 /* Probes profiling interfaces */
1488 static int probes_profile_seq_show(struct seq_file *m, void *v)
1489 {
1490         struct trace_probe *tp = v;
1491
1492         seq_printf(m, "  %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
1493                    tp->rp.kp.nmissed);
1494
1495         return 0;
1496 }
1497
1498 static const struct seq_operations profile_seq_op = {
1499         .start  = probes_seq_start,
1500         .next   = probes_seq_next,
1501         .stop   = probes_seq_stop,
1502         .show   = probes_profile_seq_show
1503 };
1504
1505 static int profile_open(struct inode *inode, struct file *file)
1506 {
1507         return seq_open(file, &profile_seq_op);
1508 }
1509
1510 static const struct file_operations kprobe_profile_ops = {
1511         .owner          = THIS_MODULE,
1512         .open           = profile_open,
1513         .read           = seq_read,
1514         .llseek         = seq_lseek,
1515         .release        = seq_release,
1516 };
1517
1518 /* Sum up total data length for dynamic arraies (strings) */
1519 static __kprobes int __get_data_size(struct trace_probe *tp,
1520                                      struct pt_regs *regs)
1521 {
1522         int i, ret = 0;
1523         u32 len;
1524
1525         for (i = 0; i < tp->nr_args; i++)
1526                 if (unlikely(tp->args[i].fetch_size.fn)) {
1527                         call_fetch(&tp->args[i].fetch_size, regs, &len);
1528                         ret += len;
1529                 }
1530
1531         return ret;
1532 }
1533
1534 /* Store the value of each argument */
1535 static __kprobes void store_trace_args(int ent_size, struct trace_probe *tp,
1536                                        struct pt_regs *regs,
1537                                        u8 *data, int maxlen)
1538 {
1539         int i;
1540         u32 end = tp->size;
1541         u32 *dl;        /* Data (relative) location */
1542
1543         for (i = 0; i < tp->nr_args; i++) {
1544                 if (unlikely(tp->args[i].fetch_size.fn)) {
1545                         /*
1546                          * First, we set the relative location and
1547                          * maximum data length to *dl
1548                          */
1549                         dl = (u32 *)(data + tp->args[i].offset);
1550                         *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
1551                         /* Then try to fetch string or dynamic array data */
1552                         call_fetch(&tp->args[i].fetch, regs, dl);
1553                         /* Reduce maximum length */
1554                         end += get_rloc_len(*dl);
1555                         maxlen -= get_rloc_len(*dl);
1556                         /* Trick here, convert data_rloc to data_loc */
1557                         *dl = convert_rloc_to_loc(*dl,
1558                                  ent_size + tp->args[i].offset);
1559                 } else
1560                         /* Just fetching data normally */
1561                         call_fetch(&tp->args[i].fetch, regs,
1562                                    data + tp->args[i].offset);
1563         }
1564 }
1565
1566 /* Kprobe handler */
1567 static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
1568 {
1569         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1570         struct kprobe_trace_entry_head *entry;
1571         struct ring_buffer_event *event;
1572         struct ring_buffer *buffer;
1573         int size, dsize, pc;
1574         unsigned long irq_flags;
1575         struct ftrace_event_call *call = &tp->call;
1576
1577         tp->nhit++;
1578
1579         local_save_flags(irq_flags);
1580         pc = preempt_count();
1581
1582         dsize = __get_data_size(tp, regs);
1583         size = sizeof(*entry) + tp->size + dsize;
1584
1585         event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1586                                                   size, irq_flags, pc);
1587         if (!event)
1588                 return;
1589
1590         entry = ring_buffer_event_data(event);
1591         entry->ip = (unsigned long)kp->addr;
1592         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1593
1594         if (!filter_current_check_discard(buffer, call, entry, event))
1595                 trace_nowake_buffer_unlock_commit_regs(buffer, event,
1596                                                        irq_flags, pc, regs);
1597 }
1598
1599 /* Kretprobe handler */
1600 static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
1601                                           struct pt_regs *regs)
1602 {
1603         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1604         struct kretprobe_trace_entry_head *entry;
1605         struct ring_buffer_event *event;
1606         struct ring_buffer *buffer;
1607         int size, pc, dsize;
1608         unsigned long irq_flags;
1609         struct ftrace_event_call *call = &tp->call;
1610
1611         local_save_flags(irq_flags);
1612         pc = preempt_count();
1613
1614         dsize = __get_data_size(tp, regs);
1615         size = sizeof(*entry) + tp->size + dsize;
1616
1617         event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1618                                                   size, irq_flags, pc);
1619         if (!event)
1620                 return;
1621
1622         entry = ring_buffer_event_data(event);
1623         entry->func = (unsigned long)tp->rp.kp.addr;
1624         entry->ret_ip = (unsigned long)ri->ret_addr;
1625         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1626
1627         if (!filter_current_check_discard(buffer, call, entry, event))
1628                 trace_nowake_buffer_unlock_commit_regs(buffer, event,
1629                                                        irq_flags, pc, regs);
1630 }
1631
1632 /* Event entry printers */
1633 enum print_line_t
1634 print_kprobe_event(struct trace_iterator *iter, int flags,
1635                    struct trace_event *event)
1636 {
1637         struct kprobe_trace_entry_head *field;
1638         struct trace_seq *s = &iter->seq;
1639         struct trace_probe *tp;
1640         u8 *data;
1641         int i;
1642
1643         field = (struct kprobe_trace_entry_head *)iter->ent;
1644         tp = container_of(event, struct trace_probe, call.event);
1645
1646         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1647                 goto partial;
1648
1649         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1650                 goto partial;
1651
1652         if (!trace_seq_puts(s, ")"))
1653                 goto partial;
1654
1655         data = (u8 *)&field[1];
1656         for (i = 0; i < tp->nr_args; i++)
1657                 if (!tp->args[i].type->print(s, tp->args[i].name,
1658                                              data + tp->args[i].offset, field))
1659                         goto partial;
1660
1661         if (!trace_seq_puts(s, "\n"))
1662                 goto partial;
1663
1664         return TRACE_TYPE_HANDLED;
1665 partial:
1666         return TRACE_TYPE_PARTIAL_LINE;
1667 }
1668
1669 enum print_line_t
1670 print_kretprobe_event(struct trace_iterator *iter, int flags,
1671                       struct trace_event *event)
1672 {
1673         struct kretprobe_trace_entry_head *field;
1674         struct trace_seq *s = &iter->seq;
1675         struct trace_probe *tp;
1676         u8 *data;
1677         int i;
1678
1679         field = (struct kretprobe_trace_entry_head *)iter->ent;
1680         tp = container_of(event, struct trace_probe, call.event);
1681
1682         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1683                 goto partial;
1684
1685         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1686                 goto partial;
1687
1688         if (!trace_seq_puts(s, " <- "))
1689                 goto partial;
1690
1691         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1692                 goto partial;
1693
1694         if (!trace_seq_puts(s, ")"))
1695                 goto partial;
1696
1697         data = (u8 *)&field[1];
1698         for (i = 0; i < tp->nr_args; i++)
1699                 if (!tp->args[i].type->print(s, tp->args[i].name,
1700                                              data + tp->args[i].offset, field))
1701                         goto partial;
1702
1703         if (!trace_seq_puts(s, "\n"))
1704                 goto partial;
1705
1706         return TRACE_TYPE_HANDLED;
1707 partial:
1708         return TRACE_TYPE_PARTIAL_LINE;
1709 }
1710
1711 #undef DEFINE_FIELD
1712 #define DEFINE_FIELD(type, item, name, is_signed)                       \
1713         do {                                                            \
1714                 ret = trace_define_field(event_call, #type, name,       \
1715                                          offsetof(typeof(field), item), \
1716                                          sizeof(field.item), is_signed, \
1717                                          FILTER_OTHER);                 \
1718                 if (ret)                                                \
1719                         return ret;                                     \
1720         } while (0)
1721
1722 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1723 {
1724         int ret, i;
1725         struct kprobe_trace_entry_head field;
1726         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1727
1728         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 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 kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1744 {
1745         int ret, i;
1746         struct kretprobe_trace_entry_head field;
1747         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1748
1749         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1750         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1751         /* Set argument names as fields */
1752         for (i = 0; i < tp->nr_args; i++) {
1753                 ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1754                                          tp->args[i].name,
1755                                          sizeof(field) + tp->args[i].offset,
1756                                          tp->args[i].type->size,
1757                                          tp->args[i].type->is_signed,
1758                                          FILTER_OTHER);
1759                 if (ret)
1760                         return ret;
1761         }
1762         return 0;
1763 }
1764
1765 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len)
1766 {
1767         int i;
1768         int pos = 0;
1769
1770         const char *fmt, *arg;
1771
1772         if (!trace_probe_is_return(tp)) {
1773                 fmt = "(%lx)";
1774                 arg = "REC->" FIELD_STRING_IP;
1775         } else {
1776                 fmt = "(%lx <- %lx)";
1777                 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1778         }
1779
1780         /* When len=0, we just calculate the needed length */
1781 #define LEN_OR_ZERO (len ? len - pos : 0)
1782
1783         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1784
1785         for (i = 0; i < tp->nr_args; i++) {
1786                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
1787                                 tp->args[i].name, tp->args[i].type->fmt);
1788         }
1789
1790         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
1791
1792         for (i = 0; i < tp->nr_args; i++) {
1793                 if (strcmp(tp->args[i].type->name, "string") == 0)
1794                         pos += snprintf(buf + pos, LEN_OR_ZERO,
1795                                         ", __get_str(%s)",
1796                                         tp->args[i].name);
1797                 else
1798                         pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
1799                                         tp->args[i].name);
1800         }
1801
1802 #undef LEN_OR_ZERO
1803
1804         /* return the length of print_fmt */
1805         return pos;
1806 }
1807
1808 static int set_print_fmt(struct trace_probe *tp)
1809 {
1810         int len;
1811         char *print_fmt;
1812
1813         /* First: called with 0 length to calculate the needed length */
1814         len = __set_print_fmt(tp, NULL, 0);
1815         print_fmt = kmalloc(len + 1, GFP_KERNEL);
1816         if (!print_fmt)
1817                 return -ENOMEM;
1818
1819         /* Second: actually write the @print_fmt */
1820         __set_print_fmt(tp, print_fmt, len + 1);
1821         tp->call.print_fmt = print_fmt;
1822
1823         return 0;
1824 }
1825
1826 #ifdef CONFIG_PERF_EVENTS
1827
1828 /* Kprobe profile handler */
1829 static __kprobes void kprobe_perf_func(struct kprobe *kp,
1830                                          struct pt_regs *regs)
1831 {
1832         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1833         struct ftrace_event_call *call = &tp->call;
1834         struct kprobe_trace_entry_head *entry;
1835         struct hlist_head *head;
1836         int size, __size, dsize;
1837         int rctx;
1838
1839         dsize = __get_data_size(tp, regs);
1840         __size = sizeof(*entry) + tp->size + dsize;
1841         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1842         size -= sizeof(u32);
1843         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1844                      "profile buffer not large enough"))
1845                 return;
1846
1847         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1848         if (!entry)
1849                 return;
1850
1851         entry->ip = (unsigned long)kp->addr;
1852         memset(&entry[1], 0, dsize);
1853         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1854
1855         head = this_cpu_ptr(call->perf_events);
1856         perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
1857 }
1858
1859 /* Kretprobe profile handler */
1860 static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
1861                                             struct pt_regs *regs)
1862 {
1863         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1864         struct ftrace_event_call *call = &tp->call;
1865         struct kretprobe_trace_entry_head *entry;
1866         struct hlist_head *head;
1867         int size, __size, dsize;
1868         int rctx;
1869
1870         dsize = __get_data_size(tp, regs);
1871         __size = sizeof(*entry) + tp->size + dsize;
1872         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1873         size -= sizeof(u32);
1874         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1875                      "profile buffer not large enough"))
1876                 return;
1877
1878         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1879         if (!entry)
1880                 return;
1881
1882         entry->func = (unsigned long)tp->rp.kp.addr;
1883         entry->ret_ip = (unsigned long)ri->ret_addr;
1884         store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1885
1886         head = this_cpu_ptr(call->perf_events);
1887         perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1, regs, head);
1888 }
1889 #endif  /* CONFIG_PERF_EVENTS */
1890
1891 static __kprobes
1892 int kprobe_register(struct ftrace_event_call *event, enum trace_reg type)
1893 {
1894         struct trace_probe *tp = (struct trace_probe *)event->data;
1895
1896         switch (type) {
1897         case TRACE_REG_REGISTER:
1898                 return enable_trace_probe(tp, TP_FLAG_TRACE);
1899         case TRACE_REG_UNREGISTER:
1900                 disable_trace_probe(tp, TP_FLAG_TRACE);
1901                 return 0;
1902
1903 #ifdef CONFIG_PERF_EVENTS
1904         case TRACE_REG_PERF_REGISTER:
1905                 return enable_trace_probe(tp, TP_FLAG_PROFILE);
1906         case TRACE_REG_PERF_UNREGISTER:
1907                 disable_trace_probe(tp, TP_FLAG_PROFILE);
1908                 return 0;
1909 #endif
1910         }
1911         return 0;
1912 }
1913
1914 static __kprobes
1915 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1916 {
1917         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1918
1919         if (tp->flags & TP_FLAG_TRACE)
1920                 kprobe_trace_func(kp, regs);
1921 #ifdef CONFIG_PERF_EVENTS
1922         if (tp->flags & TP_FLAG_PROFILE)
1923                 kprobe_perf_func(kp, regs);
1924 #endif
1925         return 0;       /* We don't tweek kernel, so just return 0 */
1926 }
1927
1928 static __kprobes
1929 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1930 {
1931         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1932
1933         if (tp->flags & TP_FLAG_TRACE)
1934                 kretprobe_trace_func(ri, regs);
1935 #ifdef CONFIG_PERF_EVENTS
1936         if (tp->flags & TP_FLAG_PROFILE)
1937                 kretprobe_perf_func(ri, regs);
1938 #endif
1939         return 0;       /* We don't tweek kernel, so just return 0 */
1940 }
1941
1942 static struct trace_event_functions kretprobe_funcs = {
1943         .trace          = print_kretprobe_event
1944 };
1945
1946 static struct trace_event_functions kprobe_funcs = {
1947         .trace          = print_kprobe_event
1948 };
1949
1950 static int register_probe_event(struct trace_probe *tp)
1951 {
1952         struct ftrace_event_call *call = &tp->call;
1953         int ret;
1954
1955         /* Initialize ftrace_event_call */
1956         INIT_LIST_HEAD(&call->class->fields);
1957         if (trace_probe_is_return(tp)) {
1958                 call->event.funcs = &kretprobe_funcs;
1959                 call->class->define_fields = kretprobe_event_define_fields;
1960         } else {
1961                 call->event.funcs = &kprobe_funcs;
1962                 call->class->define_fields = kprobe_event_define_fields;
1963         }
1964         if (set_print_fmt(tp) < 0)
1965                 return -ENOMEM;
1966         ret = register_ftrace_event(&call->event);
1967         if (!ret) {
1968                 kfree(call->print_fmt);
1969                 return -ENODEV;
1970         }
1971         call->flags = 0;
1972         call->class->reg = kprobe_register;
1973         call->data = tp;
1974         ret = trace_add_event_call(call);
1975         if (ret) {
1976                 pr_info("Failed to register kprobe event: %s\n", call->name);
1977                 kfree(call->print_fmt);
1978                 unregister_ftrace_event(&call->event);
1979         }
1980         return ret;
1981 }
1982
1983 static void unregister_probe_event(struct trace_probe *tp)
1984 {
1985         /* tp->event is unregistered in trace_remove_event_call() */
1986         trace_remove_event_call(&tp->call);
1987         kfree(tp->call.print_fmt);
1988 }
1989
1990 /* Make a debugfs interface for controlling probe points */
1991 static __init int init_kprobe_trace(void)
1992 {
1993         struct dentry *d_tracer;
1994         struct dentry *entry;
1995
1996         if (register_module_notifier(&trace_probe_module_nb))
1997                 return -EINVAL;
1998
1999         d_tracer = tracing_init_dentry();
2000         if (!d_tracer)
2001                 return 0;
2002
2003         entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
2004                                     NULL, &kprobe_events_ops);
2005
2006         /* Event list interface */
2007         if (!entry)
2008                 pr_warning("Could not create debugfs "
2009                            "'kprobe_events' entry\n");
2010
2011         /* Profile interface */
2012         entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
2013                                     NULL, &kprobe_profile_ops);
2014
2015         if (!entry)
2016                 pr_warning("Could not create debugfs "
2017                            "'kprobe_profile' entry\n");
2018         return 0;
2019 }
2020 fs_initcall(init_kprobe_trace);
2021
2022
2023 #ifdef CONFIG_FTRACE_STARTUP_TEST
2024
2025 /*
2026  * The "__used" keeps gcc from removing the function symbol
2027  * from the kallsyms table.
2028  */
2029 static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
2030                                                int a4, int a5, int a6)
2031 {
2032         return a1 + a2 + a3 + a4 + a5 + a6;
2033 }
2034
2035 static __init int kprobe_trace_self_tests_init(void)
2036 {
2037         int ret, warn = 0;
2038         int (*target)(int, int, int, int, int, int);
2039         struct trace_probe *tp;
2040
2041         target = kprobe_trace_selftest_target;
2042
2043         pr_info("Testing kprobe tracing: ");
2044
2045         ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
2046                                   "$stack $stack0 +0($stack)");
2047         if (WARN_ON_ONCE(ret)) {
2048                 pr_warning("error on probing function entry.\n");
2049                 warn++;
2050         } else {
2051                 /* Enable trace point */
2052                 tp = find_trace_probe("testprobe", KPROBE_EVENT_SYSTEM);
2053                 if (WARN_ON_ONCE(tp == NULL)) {
2054                         pr_warning("error on getting new probe.\n");
2055                         warn++;
2056                 } else
2057                         enable_trace_probe(tp, TP_FLAG_TRACE);
2058         }
2059
2060         ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
2061                                   "$retval");
2062         if (WARN_ON_ONCE(ret)) {
2063                 pr_warning("error on probing function return.\n");
2064                 warn++;
2065         } else {
2066                 /* Enable trace point */
2067                 tp = find_trace_probe("testprobe2", KPROBE_EVENT_SYSTEM);
2068                 if (WARN_ON_ONCE(tp == NULL)) {
2069                         pr_warning("error on getting new probe.\n");
2070                         warn++;
2071                 } else
2072                         enable_trace_probe(tp, TP_FLAG_TRACE);
2073         }
2074
2075         if (warn)
2076                 goto end;
2077
2078         ret = target(1, 2, 3, 4, 5, 6);
2079
2080         /* Disable trace points before removing it */
2081         tp = find_trace_probe("testprobe", KPROBE_EVENT_SYSTEM);
2082         if (WARN_ON_ONCE(tp == NULL)) {
2083                 pr_warning("error on getting test probe.\n");
2084                 warn++;
2085         } else
2086                 disable_trace_probe(tp, TP_FLAG_TRACE);
2087
2088         tp = find_trace_probe("testprobe2", KPROBE_EVENT_SYSTEM);
2089         if (WARN_ON_ONCE(tp == NULL)) {
2090                 pr_warning("error on getting 2nd test probe.\n");
2091                 warn++;
2092         } else
2093                 disable_trace_probe(tp, TP_FLAG_TRACE);
2094
2095         ret = command_trace_probe("-:testprobe");
2096         if (WARN_ON_ONCE(ret)) {
2097                 pr_warning("error on deleting a probe.\n");
2098                 warn++;
2099         }
2100
2101         ret = command_trace_probe("-:testprobe2");
2102         if (WARN_ON_ONCE(ret)) {
2103                 pr_warning("error on deleting a probe.\n");
2104                 warn++;
2105         }
2106
2107 end:
2108         release_all_trace_probes();
2109         /*
2110          * Wait for the optimizer work to finish. Otherwise it might fiddle
2111          * with probes in already freed __init text.
2112          */
2113         wait_for_kprobe_optimizer();
2114         if (warn)
2115                 pr_cont("NG: Some tests are failed. Please check them.\n");
2116         else
2117                 pr_cont("OK\n");
2118         return 0;
2119 }
2120
2121 late_initcall(kprobe_trace_self_tests_init);
2122
2123 #endif