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 <asm/bitsperlong.h>
  34
  35 #include "trace.h"
  36 #include "trace_output.h"
  37
  38 #define MAX_TRACE_ARGS 128
  39 #define MAX_ARGSTR_LEN 63
  40 #define MAX_EVENT_NAME_LEN 64
  41 #define KPROBE_EVENT_SYSTEM "kprobes"
  42
  43 /* Reserved field names */
  44 #define FIELD_STRING_IP "__probe_ip"
  45 #define FIELD_STRING_RETIP "__probe_ret_ip"
  46 #define FIELD_STRING_FUNC "__probe_func"
  47
  48 const char *reserved_field_names[] = {
  49         "common_type",
  50         "common_flags",
  51         "common_preempt_count",
  52         "common_pid",
  53         "common_tgid",
  54         "common_lock_depth",
  55         FIELD_STRING_IP,
  56         FIELD_STRING_RETIP,
  57         FIELD_STRING_FUNC,
  58 };
  59
  60 /* Printing function type */
  61 typedef int (*print_type_func_t)(struct trace_seq *, const char *, void *);
  62 #define PRINT_TYPE_FUNC_NAME(type)      print_type_##type
  63 #define PRINT_TYPE_FMT_NAME(type)       print_type_format_##type
  64
  65 /* Printing  in basic type function template */
  66 #define DEFINE_BASIC_PRINT_TYPE_FUNC(type, fmt, cast)                   \
  67 static __kprobes int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s,    \
  68                                                 const char *name, void *data)\
  69 {                                                                       \
  70         return trace_seq_printf(s, " %s=" fmt, name, (cast)*(type *)data);\
  71 }                                                                       \
  72 static const char PRINT_TYPE_FMT_NAME(type)[] = fmt;
  73
  74 DEFINE_BASIC_PRINT_TYPE_FUNC(u8, "%x", unsigned int)
  75 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, "%x", unsigned int)
  76 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, "%lx", unsigned long)
  77 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, "%llx", unsigned long long)
  78 DEFINE_BASIC_PRINT_TYPE_FUNC(s8, "%d", int)
  79 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, "%d", int)
  80 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, "%ld", long)
  81 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, "%lld", long long)
  82
  83 /* Data fetch function type */
  84 typedef void (*fetch_func_t)(struct pt_regs *, void *, void *);
  85
  86 struct fetch_param {
  87         fetch_func_t    fn;
  88         void *data;
  89 };
  90
  91 static __kprobes void call_fetch(struct fetch_param *fprm,
  92                                  struct pt_regs *regs, void *dest)
  93 {
  94         return fprm->fn(regs, fprm->data, dest);
  95 }
  96
  97 #define FETCH_FUNC_NAME(kind, type)     fetch_##kind##_##type
  98 /*
  99  * Define macro for basic types - we don't need to define s* types, because
 100  * we have to care only about bitwidth at recording time.
 101  */
 102 #define DEFINE_BASIC_FETCH_FUNCS(kind)  \
 103 DEFINE_FETCH_##kind(u8)                 \
 104 DEFINE_FETCH_##kind(u16)                \
 105 DEFINE_FETCH_##kind(u32)                \
 106 DEFINE_FETCH_##kind(u64)
 107
 108 #define CHECK_BASIC_FETCH_FUNCS(kind, fn)       \
 109         ((FETCH_FUNC_NAME(kind, u8) == fn) ||   \
 110          (FETCH_FUNC_NAME(kind, u16) == fn) ||  \
 111          (FETCH_FUNC_NAME(kind, u32) == fn) ||  \
 112          (FETCH_FUNC_NAME(kind, u64) == fn))
 113
 114 /* Data fetch function templates */
 115 #define DEFINE_FETCH_reg(type)                                          \
 116 static __kprobes void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs,  \
 117                                           void *offset, void *dest)     \
 118 {                                                                       \
 119         *(type *)dest = (type)regs_get_register(regs,                   \
 120                                 (unsigned int)((unsigned long)offset)); \
 121 }
 122 DEFINE_BASIC_FETCH_FUNCS(reg)
 123
 124 #define DEFINE_FETCH_stack(type)                                        \
 125 static __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,\
 126                                           void *offset, void *dest)     \
 127 {                                                                       \
 128         *(type *)dest = (type)regs_get_kernel_stack_nth(regs,           \
 129                                 (unsigned int)((unsigned long)offset)); \
 130 }
 131 DEFINE_BASIC_FETCH_FUNCS(stack)
 132
 133 #define DEFINE_FETCH_retval(type)                                       \
 134 static __kprobes void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs,\
 135                                           void *dummy, void *dest)      \
 136 {                                                                       \
 137         *(type *)dest = (type)regs_return_value(regs);                  \
 138 }
 139 DEFINE_BASIC_FETCH_FUNCS(retval)
 140
 141 #define DEFINE_FETCH_memory(type)                                       \
 142 static __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,\
 143                                           void *addr, void *dest)       \
 144 {                                                                       \
 145         type retval;                                                    \
 146         if (probe_kernel_address(addr, retval))                         \
 147                 *(type *)dest = 0;                                      \
 148         else                                                            \
 149                 *(type *)dest = retval;                                 \
 150 }
 151 DEFINE_BASIC_FETCH_FUNCS(memory)
 152
 153 /* Memory fetching by symbol */
 154 struct symbol_cache {
 155         char *symbol;
 156         long offset;
 157         unsigned long addr;
 158 };
 159
 160 static unsigned long update_symbol_cache(struct symbol_cache *sc)
 161 {
 162         sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
 163         if (sc->addr)
 164                 sc->addr += sc->offset;
 165         return sc->addr;
 166 }
 167
 168 static void free_symbol_cache(struct symbol_cache *sc)
 169 {
 170         kfree(sc->symbol);
 171         kfree(sc);
 172 }
 173
 174 static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
 175 {
 176         struct symbol_cache *sc;
 177
 178         if (!sym || strlen(sym) == 0)
 179                 return NULL;
 180         sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
 181         if (!sc)
 182                 return NULL;
 183
 184         sc->symbol = kstrdup(sym, GFP_KERNEL);
 185         if (!sc->symbol) {
 186                 kfree(sc);
 187                 return NULL;
 188         }
 189         sc->offset = offset;
 190
 191         update_symbol_cache(sc);
 192         return sc;
 193 }
 194
 195 #define DEFINE_FETCH_symbol(type)                                       \
 196 static __kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs,\
 197                                           void *data, void *dest)       \
 198 {                                                                       \
 199         struct symbol_cache *sc = data;                                 \
 200         if (sc->addr)                                                   \
 201                 fetch_memory_##type(regs, (void *)sc->addr, dest);      \
 202         else                                                            \
 203                 *(type *)dest = 0;                                      \
 204 }
 205 DEFINE_BASIC_FETCH_FUNCS(symbol)
 206
 207 /* Dereference memory access function */
 208 struct deref_fetch_param {
 209         struct fetch_param orig;
 210         long offset;
 211 };
 212
 213 #define DEFINE_FETCH_deref(type)                                        \
 214 static __kprobes void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs,\
 215                                             void *data, void *dest)     \
 216 {                                                                       \
 217         struct deref_fetch_param *dprm = data;                          \
 218         unsigned long addr;                                             \
 219         call_fetch(&dprm->orig, regs, &addr);                           \
 220         if (addr) {                                                     \
 221                 addr += dprm->offset;                                   \
 222                 fetch_memory_##type(regs, (void *)addr, dest);          \
 223         } else                                                          \
 224                 *(type *)dest = 0;                                      \
 225 }
 226 DEFINE_BASIC_FETCH_FUNCS(deref)
 227
 228 static __kprobes void free_deref_fetch_param(struct deref_fetch_param *data)
 229 {
 230         if (CHECK_BASIC_FETCH_FUNCS(deref, data->orig.fn))
 231                 free_deref_fetch_param(data->orig.data);
 232         else if (CHECK_BASIC_FETCH_FUNCS(symbol, data->orig.fn))
 233                 free_symbol_cache(data->orig.data);
 234         kfree(data);
 235 }
 236
 237 /* Default (unsigned long) fetch type */
 238 #define __DEFAULT_FETCH_TYPE(t) u##t
 239 #define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
 240 #define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
 241 #define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
 242
 243 #define ASSIGN_FETCH_FUNC(kind, type)   \
 244         .kind = FETCH_FUNC_NAME(kind, type)
 245
 246 #define ASSIGN_FETCH_TYPE(ptype, ftype, sign)   \
 247         {.name = #ptype,                        \
 248          .size = sizeof(ftype),                 \
 249          .is_signed = sign,                     \
 250          .print = PRINT_TYPE_FUNC_NAME(ptype),  \
 251          .fmt = PRINT_TYPE_FMT_NAME(ptype),     \
 252 ASSIGN_FETCH_FUNC(reg, ftype),                  \
 253 ASSIGN_FETCH_FUNC(stack, ftype),                \
 254 ASSIGN_FETCH_FUNC(retval, ftype),               \
 255 ASSIGN_FETCH_FUNC(memory, ftype),               \
 256 ASSIGN_FETCH_FUNC(symbol, ftype),               \
 257 ASSIGN_FETCH_FUNC(deref, ftype),                \
 258         }
 259
 260 /* Fetch type information table */
 261 static const struct fetch_type {
 262         const char      *name;          /* Name of type */
 263         size_t          size;           /* Byte size of type */
 264         int             is_signed;      /* Signed flag */
 265         print_type_func_t       print;  /* Print functions */
 266         const char      *fmt;           /* Fromat string */
 267         /* Fetch functions */
 268         fetch_func_t    reg;
 269         fetch_func_t    stack;
 270         fetch_func_t    retval;
 271         fetch_func_t    memory;
 272         fetch_func_t    symbol;
 273         fetch_func_t    deref;
 274 } fetch_type_table[] = {
 275         ASSIGN_FETCH_TYPE(u8,  u8,  0),
 276         ASSIGN_FETCH_TYPE(u16, u16, 0),
 277         ASSIGN_FETCH_TYPE(u32, u32, 0),
 278         ASSIGN_FETCH_TYPE(u64, u64, 0),
 279         ASSIGN_FETCH_TYPE(s8,  u8,  1),
 280         ASSIGN_FETCH_TYPE(s16, u16, 1),
 281         ASSIGN_FETCH_TYPE(s32, u32, 1),
 282         ASSIGN_FETCH_TYPE(s64, u64, 1),
 283 };
 284
 285 static const struct fetch_type *find_fetch_type(const char *type)
 286 {
 287         int i;
 288
 289         if (!type)
 290                 type = DEFAULT_FETCH_TYPE_STR;
 291
 292         for (i = 0; i < ARRAY_SIZE(fetch_type_table); i++)
 293                 if (strcmp(type, fetch_type_table[i].name) == 0)
 294                         return &fetch_type_table[i];
 295         return NULL;
 296 }
 297
 298 /* Special function : only accept unsigned long */
 299 static __kprobes void fetch_stack_address(struct pt_regs *regs,
 300                                           void *dummy, void *dest)
 301 {
 302         *(unsigned long *)dest = kernel_stack_pointer(regs);
 303 }
 304
 305 /**
 306  * Kprobe event core functions
 307  */
 308
 309 struct probe_arg {
 310         struct fetch_param      fetch;
 311         unsigned int            offset; /* Offset from argument entry */
 312         const char              *name;  /* Name of this argument */
 313         const char              *comm;  /* Command of this argument */
 314         const struct fetch_type *type;  /* Type of this argument */
 315 };
 316
 317 /* Flags for trace_probe */
 318 #define TP_FLAG_TRACE   1
 319 #define TP_FLAG_PROFILE 2
 320
 321 struct trace_probe {
 322         struct list_head        list;
 323         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
 324         unsigned long           nhit;
 325         unsigned int            flags;  /* For TP_FLAG_* */
 326         const char              *symbol;        /* symbol name */
 327         struct ftrace_event_class       class;
 328         struct ftrace_event_call        call;
 329         ssize_t                 size;           /* trace entry size */
 330         unsigned int            nr_args;
 331         struct probe_arg        args[];
 332 };
 333
 334 #define SIZEOF_TRACE_PROBE(n)                   \
 335         (offsetof(struct trace_probe, args) +   \
 336         (sizeof(struct probe_arg) * (n)))
 337
 338
 339 static __kprobes int probe_is_return(struct trace_probe *tp)
 340 {
 341         return tp->rp.handler != NULL;
 342 }
 343
 344 static __kprobes const char *probe_symbol(struct trace_probe *tp)
 345 {
 346         return tp->symbol ? tp->symbol : "unknown";
 347 }
 348
 349 static int register_probe_event(struct trace_probe *tp);
 350 static void unregister_probe_event(struct trace_probe *tp);
 351
 352 static DEFINE_MUTEX(probe_lock);
 353 static LIST_HEAD(probe_list);
 354
 355 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 356 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 357                                 struct pt_regs *regs);
 358
 359 /* Check the name is good for event/group */
 360 static int check_event_name(const char *name)
 361 {
 362         if (!isalpha(*name) && *name != '_')
 363                 return 0;
 364         while (*++name != '\0') {
 365                 if (!isalpha(*name) && !isdigit(*name) && *name != '_')
 366                         return 0;
 367         }
 368         return 1;
 369 }
 370
 371 /*
 372  * Allocate new trace_probe and initialize it (including kprobes).
 373  */
 374 static struct trace_probe *alloc_trace_probe(const char *group,
 375                                              const char *event,
 376                                              void *addr,
 377                                              const char *symbol,
 378                                              unsigned long offs,
 379                                              int nargs, int is_return)
 380 {
 381         struct trace_probe *tp;
 382         int ret = -ENOMEM;
 383
 384         tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
 385         if (!tp)
 386                 return ERR_PTR(ret);
 387
 388         if (symbol) {
 389                 tp->symbol = kstrdup(symbol, GFP_KERNEL);
 390                 if (!tp->symbol)
 391                         goto error;
 392                 tp->rp.kp.symbol_name = tp->symbol;
 393                 tp->rp.kp.offset = offs;
 394         } else
 395                 tp->rp.kp.addr = addr;
 396
 397         if (is_return)
 398                 tp->rp.handler = kretprobe_dispatcher;
 399         else
 400                 tp->rp.kp.pre_handler = kprobe_dispatcher;
 401
 402         if (!event || !check_event_name(event)) {
 403                 ret = -EINVAL;
 404                 goto error;
 405         }
 406
 407         tp->call.class = &tp->class;
 408         tp->call.name = kstrdup(event, GFP_KERNEL);
 409         if (!tp->call.name)
 410                 goto error;
 411
 412         if (!group || !check_event_name(group)) {
 413                 ret = -EINVAL;
 414                 goto error;
 415         }
 416
 417         tp->class.system = kstrdup(group, GFP_KERNEL);
 418         if (!tp->class.system)
 419                 goto error;
 420
 421         INIT_LIST_HEAD(&tp->list);
 422         return tp;
 423 error:
 424         kfree(tp->call.name);
 425         kfree(tp->symbol);
 426         kfree(tp);
 427         return ERR_PTR(ret);
 428 }
 429
 430 static void free_probe_arg(struct probe_arg *arg)
 431 {
 432         if (CHECK_BASIC_FETCH_FUNCS(deref, arg->fetch.fn))
 433                 free_deref_fetch_param(arg->fetch.data);
 434         else if (CHECK_BASIC_FETCH_FUNCS(symbol, arg->fetch.fn))
 435                 free_symbol_cache(arg->fetch.data);
 436         kfree(arg->name);
 437         kfree(arg->comm);
 438 }
 439
 440 static void free_trace_probe(struct trace_probe *tp)
 441 {
 442         int i;
 443
 444         for (i = 0; i < tp->nr_args; i++)
 445                 free_probe_arg(&tp->args[i]);
 446
 447         kfree(tp->call.class->system);
 448         kfree(tp->call.name);
 449         kfree(tp->symbol);
 450         kfree(tp);
 451 }
 452
 453 static struct trace_probe *find_probe_event(const char *event,
 454                                             const char *group)
 455 {
 456         struct trace_probe *tp;
 457
 458         list_for_each_entry(tp, &probe_list, list)
 459                 if (strcmp(tp->call.name, event) == 0 &&
 460                     strcmp(tp->call.class->system, group) == 0)
 461                         return tp;
 462         return NULL;
 463 }
 464
 465 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
 466 static void unregister_trace_probe(struct trace_probe *tp)
 467 {
 468         if (probe_is_return(tp))
 469                 unregister_kretprobe(&tp->rp);
 470         else
 471                 unregister_kprobe(&tp->rp.kp);
 472         list_del(&tp->list);
 473         unregister_probe_event(tp);
 474 }
 475
 476 /* Register a trace_probe and probe_event */
 477 static int register_trace_probe(struct trace_probe *tp)
 478 {
 479         struct trace_probe *old_tp;
 480         int ret;
 481
 482         mutex_lock(&probe_lock);
 483
 484         /* register as an event */
 485         old_tp = find_probe_event(tp->call.name, tp->call.class->system);
 486         if (old_tp) {
 487                 /* delete old event */
 488                 unregister_trace_probe(old_tp);
 489                 free_trace_probe(old_tp);
 490         }
 491         ret = register_probe_event(tp);
 492         if (ret) {
 493                 pr_warning("Faild to register probe event(%d)\n", ret);
 494                 goto end;
 495         }
 496
 497         tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 498         if (probe_is_return(tp))
 499                 ret = register_kretprobe(&tp->rp);
 500         else
 501                 ret = register_kprobe(&tp->rp.kp);
 502
 503         if (ret) {
 504                 pr_warning("Could not insert probe(%d)\n", ret);
 505                 if (ret == -EILSEQ) {
 506                         pr_warning("Probing address(0x%p) is not an "
 507                                    "instruction boundary.\n",
 508                                    tp->rp.kp.addr);
 509                         ret = -EINVAL;
 510                 }
 511                 unregister_probe_event(tp);
 512         } else
 513                 list_add_tail(&tp->list, &probe_list);
 514 end:
 515         mutex_unlock(&probe_lock);
 516         return ret;
 517 }
 518
 519 /* Split symbol and offset. */
 520 static int split_symbol_offset(char *symbol, unsigned long *offset)
 521 {
 522         char *tmp;
 523         int ret;
 524
 525         if (!offset)
 526                 return -EINVAL;
 527
 528         tmp = strchr(symbol, '+');
 529         if (tmp) {
 530                 /* skip sign because strict_strtol doesn't accept '+' */
 531                 ret = strict_strtoul(tmp + 1, 0, offset);
 532                 if (ret)
 533                         return ret;
 534                 *tmp = '\0';
 535         } else
 536                 *offset = 0;
 537         return 0;
 538 }
 539
 540 #define PARAM_MAX_ARGS 16
 541 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 542
 543 static int parse_probe_vars(char *arg, const struct fetch_type *t,
 544                             struct fetch_param *f, int is_return)
 545 {
 546         int ret = 0;
 547         unsigned long param;
 548
 549         if (strcmp(arg, "retval") == 0) {
 550                 if (is_return)
 551                         f->fn = t->retval;
 552                 else
 553                         ret = -EINVAL;
 554         } else if (strncmp(arg, "stack", 5) == 0) {
 555                 if (arg[5] == '\0') {
 556                         if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0)
 557                                 f->fn = fetch_stack_address;
 558                         else
 559                                 ret = -EINVAL;
 560                 } else if (isdigit(arg[5])) {
 561                         ret = strict_strtoul(arg + 5, 10, &param);
 562                         if (ret || param > PARAM_MAX_STACK)
 563                                 ret = -EINVAL;
 564                         else {
 565                                 f->fn = t->stack;
 566                                 f->data = (void *)param;
 567                         }
 568                 } else
 569                         ret = -EINVAL;
 570         } else
 571                 ret = -EINVAL;
 572         return ret;
 573 }
 574
 575 /* Recursive argument parser */
 576 static int __parse_probe_arg(char *arg, const struct fetch_type *t,
 577                              struct fetch_param *f, int is_return)
 578 {
 579         int ret = 0;
 580         unsigned long param;
 581         long offset;
 582         char *tmp;
 583
 584         switch (arg[0]) {
 585         case '$':
 586                 ret = parse_probe_vars(arg + 1, t, f, is_return);
 587                 break;
 588         case '%':       /* named register */
 589                 ret = regs_query_register_offset(arg + 1);
 590                 if (ret >= 0) {
 591                         f->fn = t->reg;
 592                         f->data = (void *)(unsigned long)ret;
 593                         ret = 0;
 594                 }
 595                 break;
 596         case '@':       /* memory or symbol */
 597                 if (isdigit(arg[1])) {
 598                         ret = strict_strtoul(arg + 1, 0, &param);
 599                         if (ret)
 600                                 break;
 601                         f->fn = t->memory;
 602                         f->data = (void *)param;
 603                 } else {
 604                         ret = split_symbol_offset(arg + 1, &offset);
 605                         if (ret)
 606                                 break;
 607                         f->data = alloc_symbol_cache(arg + 1, offset);
 608                         if (f->data)
 609                                 f->fn = t->symbol;
 610                 }
 611                 break;
 612         case '+':       /* deref memory */
 613         case '-':
 614                 tmp = strchr(arg, '(');
 615                 if (!tmp)
 616                         break;
 617                 *tmp = '\0';
 618                 ret = strict_strtol(arg + 1, 0, &offset);
 619                 if (ret)
 620                         break;
 621                 if (arg[0] == '-')
 622                         offset = -offset;
 623                 arg = tmp + 1;
 624                 tmp = strrchr(arg, ')');
 625                 if (tmp) {
 626                         struct deref_fetch_param *dprm;
 627                         const struct fetch_type *t2 = find_fetch_type(NULL);
 628                         *tmp = '\0';
 629                         dprm = kzalloc(sizeof(struct deref_fetch_param),
 630                                        GFP_KERNEL);
 631                         if (!dprm)
 632                                 return -ENOMEM;
 633                         dprm->offset = offset;
 634                         ret = __parse_probe_arg(arg, t2, &dprm->orig,
 635                                                 is_return);
 636                         if (ret)
 637                                 kfree(dprm);
 638                         else {
 639                                 f->fn = t->deref;
 640                                 f->data = (void *)dprm;
 641                         }
 642                 }
 643                 break;
 644         }
 645         if (!ret && !f->fn)
 646                 ret = -EINVAL;
 647         return ret;
 648 }
 649
 650 /* String length checking wrapper */
 651 static int parse_probe_arg(char *arg, struct trace_probe *tp,
 652                            struct probe_arg *parg, int is_return)
 653 {
 654         const char *t;
 655
 656         if (strlen(arg) > MAX_ARGSTR_LEN) {
 657                 pr_info("Argument is too long.: %s\n",  arg);
 658                 return -ENOSPC;
 659         }
 660         parg->comm = kstrdup(arg, GFP_KERNEL);
 661         if (!parg->comm) {
 662                 pr_info("Failed to allocate memory for command '%s'.\n", arg);
 663                 return -ENOMEM;
 664         }
 665         t = strchr(parg->comm, ':');
 666         if (t) {
 667                 arg[t - parg->comm] = '\0';
 668                 t++;
 669         }
 670         parg->type = find_fetch_type(t);
 671         if (!parg->type) {
 672                 pr_info("Unsupported type: %s\n", t);
 673                 return -EINVAL;
 674         }
 675         parg->offset = tp->size;
 676         tp->size += parg->type->size;
 677         return __parse_probe_arg(arg, parg->type, &parg->fetch, is_return);
 678 }
 679
 680 /* Return 1 if name is reserved or already used by another argument */
 681 static int conflict_field_name(const char *name,
 682                                struct probe_arg *args, int narg)
 683 {
 684         int i;
 685         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
 686                 if (strcmp(reserved_field_names[i], name) == 0)
 687                         return 1;
 688         for (i = 0; i < narg; i++)
 689                 if (strcmp(args[i].name, name) == 0)
 690                         return 1;
 691         return 0;
 692 }
 693
 694 static int create_trace_probe(int argc, char **argv)
 695 {
 696         /*
 697          * Argument syntax:
 698          *  - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS]
 699          *  - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS]
 700          * Fetch args:
 701          *  $retval     : fetch return value
 702          *  $stack      : fetch stack address
 703          *  $stackN     : fetch Nth of stack (N:0-)
 704          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 705          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 706          *  %REG        : fetch register REG
 707          * Dereferencing memory fetch:
 708          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 709          * Alias name of args:
 710          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 711          * Type of args:
 712          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 713          */
 714         struct trace_probe *tp;
 715         int i, ret = 0;
 716         int is_return = 0, is_delete = 0;
 717         char *symbol = NULL, *event = NULL, *group = NULL;
 718         char *arg, *tmp;
 719         unsigned long offset = 0;
 720         void *addr = NULL;
 721         char buf[MAX_EVENT_NAME_LEN];
 722
 723         /* argc must be >= 1 */
 724         if (argv[0][0] == 'p')
 725                 is_return = 0;
 726         else if (argv[0][0] == 'r')
 727                 is_return = 1;
 728         else if (argv[0][0] == '-')
 729                 is_delete = 1;
 730         else {
 731                 pr_info("Probe definition must be started with 'p', 'r' or"
 732                         " '-'.\n");
 733                 return -EINVAL;
 734         }
 735
 736         if (argv[0][1] == ':') {
 737                 event = &argv[0][2];
 738                 if (strchr(event, '/')) {
 739                         group = event;
 740                         event = strchr(group, '/') + 1;
 741                         event[-1] = '\0';
 742                         if (strlen(group) == 0) {
 743                                 pr_info("Group name is not specified\n");
 744                                 return -EINVAL;
 745                         }
 746                 }
 747                 if (strlen(event) == 0) {
 748                         pr_info("Event name is not specified\n");
 749                         return -EINVAL;
 750                 }
 751         }
 752         if (!group)
 753                 group = KPROBE_EVENT_SYSTEM;
 754
 755         if (is_delete) {
 756                 if (!event) {
 757                         pr_info("Delete command needs an event name.\n");
 758                         return -EINVAL;
 759                 }
 760                 tp = find_probe_event(event, group);
 761                 if (!tp) {
 762                         pr_info("Event %s/%s doesn't exist.\n", group, event);
 763                         return -ENOENT;
 764                 }
 765                 /* delete an event */
 766                 unregister_trace_probe(tp);
 767                 free_trace_probe(tp);
 768                 return 0;
 769         }
 770
 771         if (argc < 2) {
 772                 pr_info("Probe point is not specified.\n");
 773                 return -EINVAL;
 774         }
 775         if (isdigit(argv[1][0])) {
 776                 if (is_return) {
 777                         pr_info("Return probe point must be a symbol.\n");
 778                         return -EINVAL;
 779                 }
 780                 /* an address specified */
 781                 ret = strict_strtoul(&argv[1][0], 0, (unsigned long *)&addr);
 782                 if (ret) {
 783                         pr_info("Failed to parse address.\n");
 784                         return ret;
 785                 }
 786         } else {
 787                 /* a symbol specified */
 788                 symbol = argv[1];
 789                 /* TODO: support .init module functions */
 790                 ret = split_symbol_offset(symbol, &offset);
 791                 if (ret) {
 792                         pr_info("Failed to parse symbol.\n");
 793                         return ret;
 794                 }
 795                 if (offset && is_return) {
 796                         pr_info("Return probe must be used without offset.\n");
 797                         return -EINVAL;
 798                 }
 799         }
 800         argc -= 2; argv += 2;
 801
 802         /* setup a probe */
 803         if (!event) {
 804                 /* Make a new event name */
 805                 if (symbol)
 806                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 807                                  is_return ? 'r' : 'p', symbol, offset);
 808                 else
 809                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 810                                  is_return ? 'r' : 'p', addr);
 811                 event = buf;
 812         }
 813         tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
 814                                is_return);
 815         if (IS_ERR(tp)) {
 816                 pr_info("Failed to allocate trace_probe.(%d)\n",
 817                         (int)PTR_ERR(tp));
 818                 return PTR_ERR(tp);
 819         }
 820
 821         /* parse arguments */
 822         ret = 0;
 823         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 824                 /* Parse argument name */
 825                 arg = strchr(argv[i], '=');
 826                 if (arg)
 827                         *arg++ = '\0';
 828                 else
 829                         arg = argv[i];
 830
 831                 tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
 832                 if (!tp->args[i].name) {
 833                         pr_info("Failed to allocate argument%d name '%s'.\n",
 834                                 i, argv[i]);
 835                         ret = -ENOMEM;
 836                         goto error;
 837                 }
 838                 tmp = strchr(tp->args[i].name, ':');
 839                 if (tmp)
 840                         *tmp = '_';     /* convert : to _ */
 841
 842                 if (conflict_field_name(tp->args[i].name, tp->args, i)) {
 843                         pr_info("Argument%d name '%s' conflicts with "
 844                                 "another field.\n", i, argv[i]);
 845                         ret = -EINVAL;
 846                         goto error;
 847                 }
 848
 849                 /* Parse fetch argument */
 850                 ret = parse_probe_arg(arg, tp, &tp->args[i], is_return);
 851                 if (ret) {
 852                         pr_info("Parse error at argument%d. (%d)\n", i, ret);
 853                         kfree(tp->args[i].name);
 854                         goto error;
 855                 }
 856
 857                 tp->nr_args++;
 858         }
 859
 860         ret = register_trace_probe(tp);
 861         if (ret)
 862                 goto error;
 863         return 0;
 864
 865 error:
 866         free_trace_probe(tp);
 867         return ret;
 868 }
 869
 870 static void cleanup_all_probes(void)
 871 {
 872         struct trace_probe *tp;
 873
 874         mutex_lock(&probe_lock);
 875         /* TODO: Use batch unregistration */
 876         while (!list_empty(&probe_list)) {
 877                 tp = list_entry(probe_list.next, struct trace_probe, list);
 878                 unregister_trace_probe(tp);
 879                 free_trace_probe(tp);
 880         }
 881         mutex_unlock(&probe_lock);
 882 }
 883
 884
 885 /* Probes listing interfaces */
 886 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 887 {
 888         mutex_lock(&probe_lock);
 889         return seq_list_start(&probe_list, *pos);
 890 }
 891
 892 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 893 {
 894         return seq_list_next(v, &probe_list, pos);
 895 }
 896
 897 static void probes_seq_stop(struct seq_file *m, void *v)
 898 {
 899         mutex_unlock(&probe_lock);
 900 }
 901
 902 static int probes_seq_show(struct seq_file *m, void *v)
 903 {
 904         struct trace_probe *tp = v;
 905         int i;
 906
 907         seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p');
 908         seq_printf(m, ":%s/%s", tp->call.class->system, tp->call.name);
 909
 910         if (!tp->symbol)
 911                 seq_printf(m, " 0x%p", tp->rp.kp.addr);
 912         else if (tp->rp.kp.offset)
 913                 seq_printf(m, " %s+%u", probe_symbol(tp), tp->rp.kp.offset);
 914         else
 915                 seq_printf(m, " %s", probe_symbol(tp));
 916
 917         for (i = 0; i < tp->nr_args; i++)
 918                 seq_printf(m, " %s=%s", tp->args[i].name, tp->args[i].comm);
 919         seq_printf(m, "\n");
 920
 921         return 0;
 922 }
 923
 924 static const struct seq_operations probes_seq_op = {
 925         .start  = probes_seq_start,
 926         .next   = probes_seq_next,
 927         .stop   = probes_seq_stop,
 928         .show   = probes_seq_show
 929 };
 930
 931 static int probes_open(struct inode *inode, struct file *file)
 932 {
 933         if ((file->f_mode & FMODE_WRITE) &&
 934             (file->f_flags & O_TRUNC))
 935                 cleanup_all_probes();
 936
 937         return seq_open(file, &probes_seq_op);
 938 }
 939
 940 static int command_trace_probe(const char *buf)
 941 {
 942         char **argv;
 943         int argc = 0, ret = 0;
 944
 945         argv = argv_split(GFP_KERNEL, buf, &argc);
 946         if (!argv)
 947                 return -ENOMEM;
 948
 949         if (argc)
 950                 ret = create_trace_probe(argc, argv);
 951
 952         argv_free(argv);
 953         return ret;
 954 }
 955
 956 #define WRITE_BUFSIZE 128
 957
 958 static ssize_t probes_write(struct file *file, const char __user *buffer,
 959                             size_t count, loff_t *ppos)
 960 {
 961         char *kbuf, *tmp;
 962         int ret;
 963         size_t done;
 964         size_t size;
 965
 966         kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
 967         if (!kbuf)
 968                 return -ENOMEM;
 969
 970         ret = done = 0;
 971         while (done < count) {
 972                 size = count - done;
 973                 if (size >= WRITE_BUFSIZE)
 974                         size = WRITE_BUFSIZE - 1;
 975                 if (copy_from_user(kbuf, buffer + done, size)) {
 976                         ret = -EFAULT;
 977                         goto out;
 978                 }
 979                 kbuf[size] = '\0';
 980                 tmp = strchr(kbuf, '\n');
 981                 if (tmp) {
 982                         *tmp = '\0';
 983                         size = tmp - kbuf + 1;
 984                 } else if (done + size < count) {
 985                         pr_warning("Line length is too long: "
 986                                    "Should be less than %d.", WRITE_BUFSIZE);
 987                         ret = -EINVAL;
 988                         goto out;
 989                 }
 990                 done += size;
 991                 /* Remove comments */
 992                 tmp = strchr(kbuf, '#');
 993                 if (tmp)
 994                         *tmp = '\0';
 995
 996                 ret = command_trace_probe(kbuf);
 997                 if (ret)
 998                         goto out;
 999         }
1000         ret = done;
1001 out:
1002         kfree(kbuf);
1003         return ret;
1004 }
1005
1006 static const struct file_operations kprobe_events_ops = {
1007         .owner          = THIS_MODULE,
1008         .open           = probes_open,
1009         .read           = seq_read,
1010         .llseek         = seq_lseek,
1011         .release        = seq_release,
1012         .write          = probes_write,
1013 };
1014
1015 /* Probes profiling interfaces */
1016 static int probes_profile_seq_show(struct seq_file *m, void *v)
1017 {
1018         struct trace_probe *tp = v;
1019
1020         seq_printf(m, "  %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
1021                    tp->rp.kp.nmissed);
1022
1023         return 0;
1024 }
1025
1026 static const struct seq_operations profile_seq_op = {
1027         .start  = probes_seq_start,
1028         .next   = probes_seq_next,
1029         .stop   = probes_seq_stop,
1030         .show   = probes_profile_seq_show
1031 };
1032
1033 static int profile_open(struct inode *inode, struct file *file)
1034 {
1035         return seq_open(file, &profile_seq_op);
1036 }
1037
1038 static const struct file_operations kprobe_profile_ops = {
1039         .owner          = THIS_MODULE,
1040         .open           = profile_open,
1041         .read           = seq_read,
1042         .llseek         = seq_lseek,
1043         .release        = seq_release,
1044 };
1045
1046 /* Kprobe handler */
1047 static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
1048 {
1049         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1050         struct kprobe_trace_entry_head *entry;
1051         struct ring_buffer_event *event;
1052         struct ring_buffer *buffer;
1053         u8 *data;
1054         int size, i, pc;
1055         unsigned long irq_flags;
1056         struct ftrace_event_call *call = &tp->call;
1057
1058         tp->nhit++;
1059
1060         local_save_flags(irq_flags);
1061         pc = preempt_count();
1062
1063         size = sizeof(*entry) + tp->size;
1064
1065         event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1066                                                   size, irq_flags, pc);
1067         if (!event)
1068                 return;
1069
1070         entry = ring_buffer_event_data(event);
1071         entry->ip = (unsigned long)kp->addr;
1072         data = (u8 *)&entry[1];
1073         for (i = 0; i < tp->nr_args; i++)
1074                 call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);
1075
1076         if (!filter_current_check_discard(buffer, call, entry, event))
1077                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
1078 }
1079
1080 /* Kretprobe handler */
1081 static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
1082                                           struct pt_regs *regs)
1083 {
1084         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1085         struct kretprobe_trace_entry_head *entry;
1086         struct ring_buffer_event *event;
1087         struct ring_buffer *buffer;
1088         u8 *data;
1089         int size, i, pc;
1090         unsigned long irq_flags;
1091         struct ftrace_event_call *call = &tp->call;
1092
1093         local_save_flags(irq_flags);
1094         pc = preempt_count();
1095
1096         size = sizeof(*entry) + tp->size;
1097
1098         event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1099                                                   size, irq_flags, pc);
1100         if (!event)
1101                 return;
1102
1103         entry = ring_buffer_event_data(event);
1104         entry->func = (unsigned long)tp->rp.kp.addr;
1105         entry->ret_ip = (unsigned long)ri->ret_addr;
1106         data = (u8 *)&entry[1];
1107         for (i = 0; i < tp->nr_args; i++)
1108                 call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);
1109
1110         if (!filter_current_check_discard(buffer, call, entry, event))
1111                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
1112 }
1113
1114 /* Event entry printers */
1115 enum print_line_t
1116 print_kprobe_event(struct trace_iterator *iter, int flags,
1117                    struct trace_event *event)
1118 {
1119         struct kprobe_trace_entry_head *field;
1120         struct trace_seq *s = &iter->seq;
1121         struct trace_probe *tp;
1122         u8 *data;
1123         int i;
1124
1125         field = (struct kprobe_trace_entry_head *)iter->ent;
1126         tp = container_of(event, struct trace_probe, call.event);
1127
1128         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1129                 goto partial;
1130
1131         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1132                 goto partial;
1133
1134         if (!trace_seq_puts(s, ")"))
1135                 goto partial;
1136
1137         data = (u8 *)&field[1];
1138         for (i = 0; i < tp->nr_args; i++)
1139                 if (!tp->args[i].type->print(s, tp->args[i].name,
1140                                              data + tp->args[i].offset))
1141                         goto partial;
1142
1143         if (!trace_seq_puts(s, "\n"))
1144                 goto partial;
1145
1146         return TRACE_TYPE_HANDLED;
1147 partial:
1148         return TRACE_TYPE_PARTIAL_LINE;
1149 }
1150
1151 enum print_line_t
1152 print_kretprobe_event(struct trace_iterator *iter, int flags,
1153                       struct trace_event *event)
1154 {
1155         struct kretprobe_trace_entry_head *field;
1156         struct trace_seq *s = &iter->seq;
1157         struct trace_probe *tp;
1158         u8 *data;
1159         int i;
1160
1161         field = (struct kretprobe_trace_entry_head *)iter->ent;
1162         tp = container_of(event, struct trace_probe, call.event);
1163
1164         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1165                 goto partial;
1166
1167         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1168                 goto partial;
1169
1170         if (!trace_seq_puts(s, " <- "))
1171                 goto partial;
1172
1173         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1174                 goto partial;
1175
1176         if (!trace_seq_puts(s, ")"))
1177                 goto partial;
1178
1179         data = (u8 *)&field[1];
1180         for (i = 0; i < tp->nr_args; i++)
1181                 if (!tp->args[i].type->print(s, tp->args[i].name,
1182                                              data + tp->args[i].offset))
1183                         goto partial;
1184
1185         if (!trace_seq_puts(s, "\n"))
1186                 goto partial;
1187
1188         return TRACE_TYPE_HANDLED;
1189 partial:
1190         return TRACE_TYPE_PARTIAL_LINE;
1191 }
1192
1193 static int probe_event_enable(struct ftrace_event_call *call)
1194 {
1195         struct trace_probe *tp = (struct trace_probe *)call->data;
1196
1197         tp->flags |= TP_FLAG_TRACE;
1198         if (probe_is_return(tp))
1199                 return enable_kretprobe(&tp->rp);
1200         else
1201                 return enable_kprobe(&tp->rp.kp);
1202 }
1203
1204 static void probe_event_disable(struct ftrace_event_call *call)
1205 {
1206         struct trace_probe *tp = (struct trace_probe *)call->data;
1207
1208         tp->flags &= ~TP_FLAG_TRACE;
1209         if (!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE))) {
1210                 if (probe_is_return(tp))
1211                         disable_kretprobe(&tp->rp);
1212                 else
1213                         disable_kprobe(&tp->rp.kp);
1214         }
1215 }
1216
1217 static int probe_event_raw_init(struct ftrace_event_call *event_call)
1218 {
1219         return 0;
1220 }
1221
1222 #undef DEFINE_FIELD
1223 #define DEFINE_FIELD(type, item, name, is_signed)                       \
1224         do {                                                            \
1225                 ret = trace_define_field(event_call, #type, name,       \
1226                                          offsetof(typeof(field), item), \
1227                                          sizeof(field.item), is_signed, \
1228                                          FILTER_OTHER);                 \
1229                 if (ret)                                                \
1230                         return ret;                                     \
1231         } while (0)
1232
1233 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1234 {
1235         int ret, i;
1236         struct kprobe_trace_entry_head field;
1237         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1238
1239         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1240         /* Set argument names as fields */
1241         for (i = 0; i < tp->nr_args; i++) {
1242                 ret = trace_define_field(event_call, tp->args[i].type->name,
1243                                          tp->args[i].name,
1244                                          sizeof(field) + tp->args[i].offset,
1245                                          tp->args[i].type->size,
1246                                          tp->args[i].type->is_signed,
1247                                          FILTER_OTHER);
1248                 if (ret)
1249                         return ret;
1250         }
1251         return 0;
1252 }
1253
1254 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1255 {
1256         int ret, i;
1257         struct kretprobe_trace_entry_head field;
1258         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1259
1260         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1261         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1262         /* Set argument names as fields */
1263         for (i = 0; i < tp->nr_args; i++) {
1264                 ret = trace_define_field(event_call, tp->args[i].type->name,
1265                                          tp->args[i].name,
1266                                          sizeof(field) + tp->args[i].offset,
1267                                          tp->args[i].type->size,
1268                                          tp->args[i].type->is_signed,
1269                                          FILTER_OTHER);
1270                 if (ret)
1271                         return ret;
1272         }
1273         return 0;
1274 }
1275
1276 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len)
1277 {
1278         int i;
1279         int pos = 0;
1280
1281         const char *fmt, *arg;
1282
1283         if (!probe_is_return(tp)) {
1284                 fmt = "(%lx)";
1285                 arg = "REC->" FIELD_STRING_IP;
1286         } else {
1287                 fmt = "(%lx <- %lx)";
1288                 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1289         }
1290
1291         /* When len=0, we just calculate the needed length */
1292 #define LEN_OR_ZERO (len ? len - pos : 0)
1293
1294         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1295
1296         for (i = 0; i < tp->nr_args; i++) {
1297                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
1298                                 tp->args[i].name, tp->args[i].type->fmt);
1299         }
1300
1301         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
1302
1303         for (i = 0; i < tp->nr_args; i++) {
1304                 pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
1305                                 tp->args[i].name);
1306         }
1307
1308 #undef LEN_OR_ZERO
1309
1310         /* return the length of print_fmt */
1311         return pos;
1312 }
1313
1314 static int set_print_fmt(struct trace_probe *tp)
1315 {
1316         int len;
1317         char *print_fmt;
1318
1319         /* First: called with 0 length to calculate the needed length */
1320         len = __set_print_fmt(tp, NULL, 0);
1321         print_fmt = kmalloc(len + 1, GFP_KERNEL);
1322         if (!print_fmt)
1323                 return -ENOMEM;
1324
1325         /* Second: actually write the @print_fmt */
1326         __set_print_fmt(tp, print_fmt, len + 1);
1327         tp->call.print_fmt = print_fmt;
1328
1329         return 0;
1330 }
1331
1332 #ifdef CONFIG_PERF_EVENTS
1333
1334 /* Kprobe profile handler */
1335 static __kprobes void kprobe_perf_func(struct kprobe *kp,
1336                                          struct pt_regs *regs)
1337 {
1338         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1339         struct ftrace_event_call *call = &tp->call;
1340         struct kprobe_trace_entry_head *entry;
1341         struct hlist_head *head;
1342         u8 *data;
1343         int size, __size, i;
1344         int rctx;
1345
1346         __size = sizeof(*entry) + tp->size;
1347         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1348         size -= sizeof(u32);
1349         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1350                      "profile buffer not large enough"))
1351                 return;
1352
1353         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1354         if (!entry)
1355                 return;
1356
1357         entry->ip = (unsigned long)kp->addr;
1358         data = (u8 *)&entry[1];
1359         for (i = 0; i < tp->nr_args; i++)
1360                 call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);
1361
1362         head = this_cpu_ptr(call->perf_events);
1363         perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
1364 }
1365
1366 /* Kretprobe profile handler */
1367 static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
1368                                             struct pt_regs *regs)
1369 {
1370         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1371         struct ftrace_event_call *call = &tp->call;
1372         struct kretprobe_trace_entry_head *entry;
1373         struct hlist_head *head;
1374         u8 *data;
1375         int size, __size, i;
1376         int rctx;
1377
1378         __size = sizeof(*entry) + tp->size;
1379         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1380         size -= sizeof(u32);
1381         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1382                      "profile buffer not large enough"))
1383                 return;
1384
1385         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1386         if (!entry)
1387                 return;
1388
1389         entry->func = (unsigned long)tp->rp.kp.addr;
1390         entry->ret_ip = (unsigned long)ri->ret_addr;
1391         data = (u8 *)&entry[1];
1392         for (i = 0; i < tp->nr_args; i++)
1393                 call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);
1394
1395         head = this_cpu_ptr(call->perf_events);
1396         perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1, regs, head);
1397 }
1398
1399 static int probe_perf_enable(struct ftrace_event_call *call)
1400 {
1401         struct trace_probe *tp = (struct trace_probe *)call->data;
1402
1403         tp->flags |= TP_FLAG_PROFILE;
1404
1405         if (probe_is_return(tp))
1406                 return enable_kretprobe(&tp->rp);
1407         else
1408                 return enable_kprobe(&tp->rp.kp);
1409 }
1410
1411 static void probe_perf_disable(struct ftrace_event_call *call)
1412 {
1413         struct trace_probe *tp = (struct trace_probe *)call->data;
1414
1415         tp->flags &= ~TP_FLAG_PROFILE;
1416
1417         if (!(tp->flags & TP_FLAG_TRACE)) {
1418                 if (probe_is_return(tp))
1419                         disable_kretprobe(&tp->rp);
1420                 else
1421                         disable_kprobe(&tp->rp.kp);
1422         }
1423 }
1424 #endif  /* CONFIG_PERF_EVENTS */
1425
1426 static __kprobes
1427 int kprobe_register(struct ftrace_event_call *event, enum trace_reg type)
1428 {
1429         switch (type) {
1430         case TRACE_REG_REGISTER:
1431                 return probe_event_enable(event);
1432         case TRACE_REG_UNREGISTER:
1433                 probe_event_disable(event);
1434                 return 0;
1435
1436 #ifdef CONFIG_PERF_EVENTS
1437         case TRACE_REG_PERF_REGISTER:
1438                 return probe_perf_enable(event);
1439         case TRACE_REG_PERF_UNREGISTER:
1440                 probe_perf_disable(event);
1441                 return 0;
1442 #endif
1443         }
1444         return 0;
1445 }
1446
1447 static __kprobes
1448 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1449 {
1450         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1451
1452         if (tp->flags & TP_FLAG_TRACE)
1453                 kprobe_trace_func(kp, regs);
1454 #ifdef CONFIG_PERF_EVENTS
1455         if (tp->flags & TP_FLAG_PROFILE)
1456                 kprobe_perf_func(kp, regs);
1457 #endif
1458         return 0;       /* We don't tweek kernel, so just return 0 */
1459 }
1460
1461 static __kprobes
1462 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1463 {
1464         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1465
1466         if (tp->flags & TP_FLAG_TRACE)
1467                 kretprobe_trace_func(ri, regs);
1468 #ifdef CONFIG_PERF_EVENTS
1469         if (tp->flags & TP_FLAG_PROFILE)
1470                 kretprobe_perf_func(ri, regs);
1471 #endif
1472         return 0;       /* We don't tweek kernel, so just return 0 */
1473 }
1474
1475 static struct trace_event_functions kretprobe_funcs = {
1476         .trace          = print_kretprobe_event
1477 };
1478
1479 static struct trace_event_functions kprobe_funcs = {
1480         .trace          = print_kprobe_event
1481 };
1482
1483 static int register_probe_event(struct trace_probe *tp)
1484 {
1485         struct ftrace_event_call *call = &tp->call;
1486         int ret;
1487
1488         /* Initialize ftrace_event_call */
1489         if (probe_is_return(tp)) {
1490                 INIT_LIST_HEAD(&call->class->fields);
1491                 call->event.funcs = &kretprobe_funcs;
1492                 call->class->raw_init = probe_event_raw_init;
1493                 call->class->define_fields = kretprobe_event_define_fields;
1494         } else {
1495                 INIT_LIST_HEAD(&call->class->fields);
1496                 call->event.funcs = &kprobe_funcs;
1497                 call->class->raw_init = probe_event_raw_init;
1498                 call->class->define_fields = kprobe_event_define_fields;
1499         }
1500         if (set_print_fmt(tp) < 0)
1501                 return -ENOMEM;
1502         ret = register_ftrace_event(&call->event);
1503         if (!ret) {
1504                 kfree(call->print_fmt);
1505                 return -ENODEV;
1506         }
1507         call->flags = 0;
1508         call->class->reg = kprobe_register;
1509         call->data = tp;
1510         ret = trace_add_event_call(call);
1511         if (ret) {
1512                 pr_info("Failed to register kprobe event: %s\n", call->name);
1513                 kfree(call->print_fmt);
1514                 unregister_ftrace_event(&call->event);
1515         }
1516         return ret;
1517 }
1518
1519 static void unregister_probe_event(struct trace_probe *tp)
1520 {
1521         /* tp->event is unregistered in trace_remove_event_call() */
1522         trace_remove_event_call(&tp->call);
1523         kfree(tp->call.print_fmt);
1524 }
1525
1526 /* Make a debugfs interface for controling probe points */
1527 static __init int init_kprobe_trace(void)
1528 {
1529         struct dentry *d_tracer;
1530         struct dentry *entry;
1531
1532         d_tracer = tracing_init_dentry();
1533         if (!d_tracer)
1534                 return 0;
1535
1536         entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1537                                     NULL, &kprobe_events_ops);
1538
1539         /* Event list interface */
1540         if (!entry)
1541                 pr_warning("Could not create debugfs "
1542                            "'kprobe_events' entry\n");
1543
1544         /* Profile interface */
1545         entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1546                                     NULL, &kprobe_profile_ops);
1547
1548         if (!entry)
1549                 pr_warning("Could not create debugfs "
1550                            "'kprobe_profile' entry\n");
1551         return 0;
1552 }
1553 fs_initcall(init_kprobe_trace);
1554
1555
1556 #ifdef CONFIG_FTRACE_STARTUP_TEST
1557
1558 static int kprobe_trace_selftest_target(int a1, int a2, int a3,
1559                                         int a4, int a5, int a6)
1560 {
1561         return a1 + a2 + a3 + a4 + a5 + a6;
1562 }
1563
1564 static __init int kprobe_trace_self_tests_init(void)
1565 {
1566         int ret, warn = 0;
1567         int (*target)(int, int, int, int, int, int);
1568         struct trace_probe *tp;
1569
1570         target = kprobe_trace_selftest_target;
1571
1572         pr_info("Testing kprobe tracing: ");
1573
1574         ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
1575                                   "$stack $stack0 +0($stack)");
1576         if (WARN_ON_ONCE(ret)) {
1577                 pr_warning("error on probing function entry.\n");
1578                 warn++;
1579         } else {
1580                 /* Enable trace point */
1581                 tp = find_probe_event("testprobe", KPROBE_EVENT_SYSTEM);
1582                 if (WARN_ON_ONCE(tp == NULL)) {
1583                         pr_warning("error on getting new probe.\n");
1584                         warn++;
1585                 } else
1586                         probe_event_enable(&tp->call);
1587         }
1588
1589         ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
1590                                   "$retval");
1591         if (WARN_ON_ONCE(ret)) {
1592                 pr_warning("error on probing function return.\n");
1593                 warn++;
1594         } else {
1595                 /* Enable trace point */
1596                 tp = find_probe_event("testprobe2", KPROBE_EVENT_SYSTEM);
1597                 if (WARN_ON_ONCE(tp == NULL)) {
1598                         pr_warning("error on getting new probe.\n");
1599                         warn++;
1600                 } else
1601                         probe_event_enable(&tp->call);
1602         }
1603
1604         if (warn)
1605                 goto end;
1606
1607         ret = target(1, 2, 3, 4, 5, 6);
1608
1609         ret = command_trace_probe("-:testprobe");
1610         if (WARN_ON_ONCE(ret)) {
1611                 pr_warning("error on deleting a probe.\n");
1612                 warn++;
1613         }
1614
1615         ret = command_trace_probe("-:testprobe2");
1616         if (WARN_ON_ONCE(ret)) {
1617                 pr_warning("error on deleting a probe.\n");
1618                 warn++;
1619         }
1620
1621 end:
1622         cleanup_all_probes();
1623         if (warn)
1624                 pr_cont("NG: Some tests are failed. Please check them.\n");
1625         else
1626                 pr_cont("OK\n");
1627         return 0;
1628 }
1629
1630 late_initcall(kprobe_trace_self_tests_init);
1631
1632 #endif