kernel/trace/trace_kprobe.c

   1 /*
   2  * Kprobes-based tracing events
   3  *
   4  * Created by Masami Hiramatsu <[email protected]>
   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_call        call;
 328         struct trace_event              event;
 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.name = kstrdup(event, GFP_KERNEL);
 408         if (!tp->call.name)
 409                 goto error;
 410
 411         if (!group || !check_event_name(group)) {
 412                 ret = -EINVAL;
 413                 goto error;
 414         }
 415
 416         tp->call.system = kstrdup(group, GFP_KERNEL);
 417         if (!tp->call.system)
 418                 goto error;
 419
 420         INIT_LIST_HEAD(&tp->list);
 421         return tp;
 422 error:
 423         kfree(tp->call.name);
 424         kfree(tp->symbol);
 425         kfree(tp);
 426         return ERR_PTR(ret);
 427 }
 428
 429 static void free_probe_arg(struct probe_arg *arg)
 430 {
 431         if (CHECK_BASIC_FETCH_FUNCS(deref, arg->fetch.fn))
 432                 free_deref_fetch_param(arg->fetch.data);
 433         else if (CHECK_BASIC_FETCH_FUNCS(symbol, arg->fetch.fn))
 434                 free_symbol_cache(arg->fetch.data);
 435         kfree(arg->name);
 436         kfree(arg->comm);
 437 }
 438
 439 static void free_trace_probe(struct trace_probe *tp)
 440 {
 441         int i;
 442
 443         for (i = 0; i < tp->nr_args; i++)
 444                 free_probe_arg(&tp->args[i]);
 445
 446         kfree(tp->call.system);
 447         kfree(tp->call.name);
 448         kfree(tp->symbol);
 449         kfree(tp);
 450 }
 451
 452 static struct trace_probe *find_probe_event(const char *event,
 453                                             const char *group)
 454 {
 455         struct trace_probe *tp;
 456
 457         list_for_each_entry(tp, &probe_list, list)
 458                 if (strcmp(tp->call.name, event) == 0 &&
 459                     strcmp(tp->call.system, group) == 0)
 460                         return tp;
 461         return NULL;
 462 }
 463
 464 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
 465 static void unregister_trace_probe(struct trace_probe *tp)
 466 {
 467         if (probe_is_return(tp))
 468                 unregister_kretprobe(&tp->rp);
 469         else
 470                 unregister_kprobe(&tp->rp.kp);
 471         list_del(&tp->list);
 472         unregister_probe_event(tp);
 473 }
 474
 475 /* Register a trace_probe and probe_event */
 476 static int register_trace_probe(struct trace_probe *tp)
 477 {
 478         struct trace_probe *old_tp;
 479         int ret;
 480
 481         mutex_lock(&probe_lock);
 482
 483         /* register as an event */
 484         old_tp = find_probe_event(tp->call.name, tp->call.system);
 485         if (old_tp) {
 486                 /* delete old event */
 487                 unregister_trace_probe(old_tp);
 488                 free_trace_probe(old_tp);
 489         }
 490         ret = register_probe_event(tp);
 491         if (ret) {
 492                 pr_warning("Faild to register probe event(%d)\n", ret);
 493                 goto end;
 494         }
 495
 496         tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 497         if (probe_is_return(tp))
 498                 ret = register_kretprobe(&tp->rp);
 499         else
 500                 ret = register_kprobe(&tp->rp.kp);
 501
 502         if (ret) {
 503                 pr_warning("Could not insert probe(%d)\n", ret);
 504                 if (ret == -EILSEQ) {
 505                         pr_warning("Probing address(0x%p) is not an "
 506                                    "instruction boundary.\n",
 507                                    tp->rp.kp.addr);
 508                         ret = -EINVAL;
 509                 }
 510                 unregister_probe_event(tp);
 511         } else
 512                 list_add_tail(&tp->list, &probe_list);
 513 end:
 514         mutex_unlock(&probe_lock);
 515         return ret;
 516 }
 517
 518 /* Split symbol and offset. */
 519 static int split_symbol_offset(char *symbol, unsigned long *offset)
 520 {
 521         char *tmp;
 522         int ret;
 523
 524         if (!offset)
 525                 return -EINVAL;
 526
 527         tmp = strchr(symbol, '+');
 528         if (tmp) {
 529                 /* skip sign because strict_strtol doesn't accept '+' */
 530                 ret = strict_strtoul(tmp + 1, 0, offset);
 531                 if (ret)
 532                         return ret;
 533                 *tmp = '\0';
 534         } else
 535                 *offset = 0;
 536         return 0;
 537 }
 538
 539 #define PARAM_MAX_ARGS 16
 540 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 541
 542 static int parse_probe_vars(char *arg, const struct fetch_type *t,
 543                             struct fetch_param *f, int is_return)
 544 {
 545         int ret = 0;
 546         unsigned long param;
 547
 548         if (strcmp(arg, "retval") == 0) {
 549                 if (is_return)
 550                         f->fn = t->retval;
 551                 else
 552                         ret = -EINVAL;
 553         } else if (strncmp(arg, "stack", 5) == 0) {
 554                 if (arg[5] == '\0') {
 555                         if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0)
 556                                 f->fn = fetch_stack_address;
 557                         else
 558                                 ret = -EINVAL;
 559                 } else if (isdigit(arg[5])) {
 560                         ret = strict_strtoul(arg + 5, 10, &param);
 561                         if (ret || param > PARAM_MAX_STACK)
 562                                 ret = -EINVAL;
 563                         else {
 564                                 f->fn = t->stack;
 565                                 f->data = (void *)param;
 566                         }
 567                 } else
 568                         ret = -EINVAL;
 569         } else
 570                 ret = -EINVAL;
 571         return ret;
 572 }
 573
 574 /* Recursive argument parser */
 575 static int __parse_probe_arg(char *arg, const struct fetch_type *t,
 576                              struct fetch_param *f, int is_return)
 577 {
 578         int ret = 0;
 579         unsigned long param;
 580         long offset;
 581         char *tmp;
 582
 583         switch (arg[0]) {
 584         case '$':
 585                 ret = parse_probe_vars(arg + 1, t, f, is_return);
 586                 break;
 587         case '%':       /* named register */
 588                 ret = regs_query_register_offset(arg + 1);
 589                 if (ret >= 0) {
 590                         f->fn = t->reg;
 591                         f->data = (void *)(unsigned long)ret;
 592                         ret = 0;
 593                 }
 594                 break;
 595         case '@':       /* memory or symbol */
 596                 if (isdigit(arg[1])) {
 597                         ret = strict_strtoul(arg + 1, 0, &param);
 598                         if (ret)
 599                                 break;
 600                         f->fn = t->memory;
 601                         f->data = (void *)param;
 602                 } else {
 603                         ret = split_symbol_offset(arg + 1, &offset);
 604                         if (ret)
 605                                 break;
 606                         f->data = alloc_symbol_cache(arg + 1, offset);
 607                         if (f->data)
 608                                 f->fn = t->symbol;
 609                 }
 610                 break;
 611         case '+':       /* deref memory */
 612         case '-':
 613                 tmp = strchr(arg, '(');
 614                 if (!tmp)
 615                         break;
 616                 *tmp = '\0';
 617                 ret = strict_strtol(arg + 1, 0, &offset);
 618                 if (ret)
 619                         break;
 620                 if (arg[0] == '-')
 621                         offset = -offset;
 622                 arg = tmp + 1;
 623                 tmp = strrchr(arg, ')');
 624                 if (tmp) {
 625                         struct deref_fetch_param *dprm;
 626                         const struct fetch_type *t2 = find_fetch_type(NULL);
 627                         *tmp = '\0';
 628                         dprm = kzalloc(sizeof(struct deref_fetch_param),
 629                                        GFP_KERNEL);
 630                         if (!dprm)
 631                                 return -ENOMEM;
 632                         dprm->offset = offset;
 633                         ret = __parse_probe_arg(arg, t2, &dprm->orig,
 634                                                 is_return);
 635                         if (ret)
 636                                 kfree(dprm);
 637                         else {
 638                                 f->fn = t->deref;
 639                                 f->data = (void *)dprm;
 640                         }
 641                 }
 642                 break;
 643         }
 644         if (!ret && !f->fn)
 645                 ret = -EINVAL;
 646         return ret;
 647 }
 648
 649 /* String length checking wrapper */
 650 static int parse_probe_arg(char *arg, struct trace_probe *tp,
 651                            struct probe_arg *parg, int is_return)
 652 {
 653         const char *t;
 654
 655         if (strlen(arg) > MAX_ARGSTR_LEN) {
 656                 pr_info("Argument is too long.: %s\n",  arg);
 657                 return -ENOSPC;
 658         }
 659         parg->comm = kstrdup(arg, GFP_KERNEL);
 660         if (!parg->comm) {
 661                 pr_info("Failed to allocate memory for command '%s'.\n", arg);
 662                 return -ENOMEM;
 663         }
 664         t = strchr(parg->comm, ':');
 665         if (t) {
 666                 arg[t - parg->comm] = '\0';
 667                 t++;
 668         }
 669         parg->type = find_fetch_type(t);
 670         if (!parg->type) {
 671                 pr_info("Unsupported type: %s\n", t);
 672                 return -EINVAL;
 673         }
 674         parg->offset = tp->size;
 675         tp->size += parg->type->size;
 676         return __parse_probe_arg(arg, parg->type, &parg->fetch, is_return);
 677 }
 678
 679 /* Return 1 if name is reserved or already used by another argument */
 680 static int conflict_field_name(const char *name,
 681                                struct probe_arg *args, int narg)
 682 {
 683         int i;
 684         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
 685                 if (strcmp(reserved_field_names[i], name) == 0)
 686                         return 1;
 687         for (i = 0; i < narg; i++)
 688                 if (strcmp(args[i].name, name) == 0)
 689                         return 1;
 690         return 0;
 691 }
 692
 693 static int create_trace_probe(int argc, char **argv)
 694 {
 695         /*
 696          * Argument syntax:
 697          *  - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS]
 698          *  - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS]
 699          * Fetch args:
 700          *  $retval     : fetch return value
 701          *  $stack      : fetch stack address
 702          *  $stackN     : fetch Nth of stack (N:0-)
 703          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 704          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 705          *  %REG        : fetch register REG
 706          * Dereferencing memory fetch:
 707          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 708          * Alias name of args:
 709          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 710          * Type of args:
 711          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 712          */
 713         struct trace_probe *tp;
 714         int i, ret = 0;
 715         int is_return = 0, is_delete = 0;
 716         char *symbol = NULL, *event = NULL, *group = NULL;
 717         char *arg, *tmp;
 718         unsigned long offset = 0;
 719         void *addr = NULL;
 720         char buf[MAX_EVENT_NAME_LEN];
 721
 722         /* argc must be >= 1 */
 723         if (argv[0][0] == 'p')
 724                 is_return = 0;
 725         else if (argv[0][0] == 'r')
 726                 is_return = 1;
 727         else if (argv[0][0] == '-')
 728                 is_delete = 1;
 729         else {
 730                 pr_info("Probe definition must be started with 'p', 'r' or"
 731                         " '-'.\n");
 732                 return -EINVAL;
 733         }
 734
 735         if (argv[0][1] == ':') {
 736                 event = &argv[0][2];
 737                 if (strchr(event, '/')) {
 738                         group = event;
 739                         event = strchr(group, '/') + 1;
 740                         event[-1] = '\0';
 741                         if (strlen(group) == 0) {
 742                                 pr_info("Group name is not specified\n");
 743                                 return -EINVAL;
 744                         }
 745                 }
 746                 if (strlen(event) == 0) {
 747                         pr_info("Event name is not specified\n");
 748                         return -EINVAL;
 749                 }
 750         }
 751         if (!group)
 752                 group = KPROBE_EVENT_SYSTEM;
 753
 754         if (is_delete) {
 755                 if (!event) {
 756                         pr_info("Delete command needs an event name.\n");
 757                         return -EINVAL;
 758                 }
 759                 tp = find_probe_event(event, group);
 760                 if (!tp) {
 761                         pr_info("Event %s/%s doesn't exist.\n", group, event);
 762                         return -ENOENT;
 763                 }
 764                 /* delete an event */
 765                 unregister_trace_probe(tp);
 766                 free_trace_probe(tp);
 767                 return 0;
 768         }
 769
 770         if (argc < 2) {
 771                 pr_info("Probe point is not specified.\n");
 772                 return -EINVAL;
 773         }
 774         if (isdigit(argv[1][0])) {
 775                 if (is_return) {
 776                         pr_info("Return probe point must be a symbol.\n");
 777                         return -EINVAL;
 778                 }
 779                 /* an address specified */
 780                 ret = strict_strtoul(&argv[1][0], 0, (unsigned long *)&addr);
 781                 if (ret) {
 782                         pr_info("Failed to parse address.\n");
 783                         return ret;
 784                 }
 785         } else {
 786                 /* a symbol specified */
 787                 symbol = argv[1];
 788                 /* TODO: support .init module functions */
 789                 ret = split_symbol_offset(symbol, &offset);
 790                 if (ret) {
 791                         pr_info("Failed to parse symbol.\n");
 792                         return ret;
 793                 }
 794                 if (offset && is_return) {
 795                         pr_info("Return probe must be used without offset.\n");
 796                         return -EINVAL;
 797                 }
 798         }
 799         argc -= 2; argv += 2;
 800
 801         /* setup a probe */
 802         if (!event) {
 803                 /* Make a new event name */
 804                 if (symbol)
 805                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 806                                  is_return ? 'r' : 'p', symbol, offset);
 807                 else
 808                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 809                                  is_return ? 'r' : 'p', addr);
 810                 event = buf;
 811         }
 812         tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
 813                                is_return);
 814         if (IS_ERR(tp)) {
 815                 pr_info("Failed to allocate trace_probe.(%d)\n",
 816                         (int)PTR_ERR(tp));
 817                 return PTR_ERR(tp);
 818         }
 819
 820         /* parse arguments */
 821         ret = 0;
 822         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 823                 /* Parse argument name */
 824                 arg = strchr(argv[i], '=');
 825                 if (arg)
 826                         *arg++ = '\0';
 827                 else
 828                         arg = argv[i];
 829
 830                 tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
 831                 if (!tp->args[i].name) {
 832                         pr_info("Failed to allocate argument%d name '%s'.\n",
 833                                 i, argv[i]);
 834                         ret = -ENOMEM;
 835                         goto error;
 836                 }
 837                 tmp = strchr(tp->args[i].name, ':');
 838                 if (tmp)
 839                         *tmp = '_';     /* convert : to _ */
 840
 841                 if (conflict_field_name(tp->args[i].name, tp->args, i)) {
 842                         pr_info("Argument%d name '%s' conflicts with "
 843                                 "another field.\n", i, argv[i]);
 844                         ret = -EINVAL;
 845                         goto error;
 846                 }
 847
 848                 /* Parse fetch argument */
 849                 ret = parse_probe_arg(arg, tp, &tp->args[i], is_return);
 850                 if (ret) {
 851                         pr_info("Parse error at argument%d. (%d)\n", i, ret);
 852                         kfree(tp->args[i].name);
 853                         goto error;
 854                 }
 855
 856                 tp->nr_args++;
 857         }
 858
 859         ret = register_trace_probe(tp);
 860         if (ret)
 861                 goto error;
 862         return 0;
 863
 864 error:
 865         free_trace_probe(tp);
 866         return ret;
 867 }
 868
 869 static void cleanup_all_probes(void)
 870 {
 871         struct trace_probe *tp;
 872
 873         mutex_lock(&probe_lock);
 874         /* TODO: Use batch unregistration */
 875         while (!list_empty(&probe_list)) {
 876                 tp = list_entry(probe_list.next, struct trace_probe, list);
 877                 unregister_trace_probe(tp);
 878                 free_trace_probe(tp);
 879         }
 880         mutex_unlock(&probe_lock);
 881 }
 882
 883
 884 /* Probes listing interfaces */
 885 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
 886 {
 887         mutex_lock(&probe_lock);
 888         return seq_list_start(&probe_list, *pos);
 889 }
 890
 891 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
 892 {
 893         return seq_list_next(v, &probe_list, pos);
 894 }
 895
 896 static void probes_seq_stop(struct seq_file *m, void *v)
 897 {
 898         mutex_unlock(&probe_lock);
 899 }
 900
 901 static int probes_seq_show(struct seq_file *m, void *v)
 902 {
 903         struct trace_probe *tp = v;
 904         int i;
 905
 906         seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p');
 907         seq_printf(m, ":%s/%s", tp->call.system, tp->call.name);
 908
 909         if (!tp->symbol)
 910                 seq_printf(m, " 0x%p", tp->rp.kp.addr);
 911         else if (tp->rp.kp.offset)
 912                 seq_printf(m, " %s+%u", probe_symbol(tp), tp->rp.kp.offset);
 913         else
 914                 seq_printf(m, " %s", probe_symbol(tp));
 915
 916         for (i = 0; i < tp->nr_args; i++)
 917                 seq_printf(m, " %s=%s", tp->args[i].name, tp->args[i].comm);
 918         seq_printf(m, "\n");
 919
 920         return 0;
 921 }
 922
 923 static const struct seq_operations probes_seq_op = {
 924         .start  = probes_seq_start,
 925         .next   = probes_seq_next,
 926         .stop   = probes_seq_stop,
 927         .show   = probes_seq_show
 928 };
 929
 930 static int probes_open(struct inode *inode, struct file *file)
 931 {
 932         if ((file->f_mode & FMODE_WRITE) &&
 933             (file->f_flags & O_TRUNC))
 934                 cleanup_all_probes();
 935
 936         return seq_open(file, &probes_seq_op);
 937 }
 938
 939 static int command_trace_probe(const char *buf)
 940 {
 941         char **argv;
 942         int argc = 0, ret = 0;
 943
 944         argv = argv_split(GFP_KERNEL, buf, &argc);
 945         if (!argv)
 946                 return -ENOMEM;
 947
 948         if (argc)
 949                 ret = create_trace_probe(argc, argv);
 950
 951         argv_free(argv);
 952         return ret;
 953 }
 954
 955 #define WRITE_BUFSIZE 128
 956
 957 static ssize_t probes_write(struct file *file, const char __user *buffer,
 958                             size_t count, loff_t *ppos)
 959 {
 960         char *kbuf, *tmp;
 961         int ret;
 962         size_t done;
 963         size_t size;
 964
 965         kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
 966         if (!kbuf)
 967                 return -ENOMEM;
 968
 969         ret = done = 0;
 970         while (done < count) {
 971                 size = count - done;
 972                 if (size >= WRITE_BUFSIZE)
 973                         size = WRITE_BUFSIZE - 1;
 974                 if (copy_from_user(kbuf, buffer + done, size)) {
 975                         ret = -EFAULT;
 976                         goto out;
 977                 }
 978                 kbuf[size] = '\0';
 979                 tmp = strchr(kbuf, '\n');
 980                 if (tmp) {
 981                         *tmp = '\0';
 982                         size = tmp - kbuf + 1;
 983                 } else if (done + size < count) {
 984                         pr_warning("Line length is too long: "
 985                                    "Should be less than %d.", WRITE_BUFSIZE);
 986                         ret = -EINVAL;
 987                         goto out;
 988                 }
 989                 done += size;
 990                 /* Remove comments */
 991                 tmp = strchr(kbuf, '#');
 992                 if (tmp)
 993                         *tmp = '\0';
 994
 995                 ret = command_trace_probe(kbuf);
 996                 if (ret)
 997                         goto out;
 998         }
 999         ret = done;
1000 out:
1001         kfree(kbuf);
1002         return ret;
1003 }
1004
1005 static const struct file_operations kprobe_events_ops = {
1006         .owner          = THIS_MODULE,
1007         .open           = probes_open,
1008         .read           = seq_read,
1009         .llseek         = seq_lseek,
1010         .release        = seq_release,
1011         .write          = probes_write,
1012 };
1013
1014 /* Probes profiling interfaces */
1015 static int probes_profile_seq_show(struct seq_file *m, void *v)
1016 {
1017         struct trace_probe *tp = v;
1018
1019         seq_printf(m, "  %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
1020                    tp->rp.kp.nmissed);
1021
1022         return 0;
1023 }
1024
1025 static const struct seq_operations profile_seq_op = {
1026         .start  = probes_seq_start,
1027         .next   = probes_seq_next,
1028         .stop   = probes_seq_stop,
1029         .show   = probes_profile_seq_show
1030 };
1031
1032 static int profile_open(struct inode *inode, struct file *file)
1033 {
1034         return seq_open(file, &profile_seq_op);
1035 }
1036
1037 static const struct file_operations kprobe_profile_ops = {
1038         .owner          = THIS_MODULE,
1039         .open           = profile_open,
1040         .read           = seq_read,
1041         .llseek         = seq_lseek,
1042         .release        = seq_release,
1043 };
1044
1045 /* Kprobe handler */
1046 static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
1047 {
1048         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1049         struct kprobe_trace_entry_head *entry;
1050         struct ring_buffer_event *event;
1051         struct ring_buffer *buffer;
1052         u8 *data;
1053         int size, i, pc;
1054         unsigned long irq_flags;
1055         struct ftrace_event_call *call = &tp->call;
1056
1057         tp->nhit++;
1058
1059         local_save_flags(irq_flags);
1060         pc = preempt_count();
1061
1062         size = sizeof(*entry) + tp->size;
1063
1064         event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
1065                                                   irq_flags, pc);
1066         if (!event)
1067                 return;
1068
1069         entry = ring_buffer_event_data(event);
1070         entry->ip = (unsigned long)kp->addr;
1071         data = (u8 *)&entry[1];
1072         for (i = 0; i < tp->nr_args; i++)
1073                 call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);
1074
1075         if (!filter_current_check_discard(buffer, call, entry, event))
1076                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
1077 }
1078
1079 /* Kretprobe handler */
1080 static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
1081                                           struct pt_regs *regs)
1082 {
1083         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1084         struct kretprobe_trace_entry_head *entry;
1085         struct ring_buffer_event *event;
1086         struct ring_buffer *buffer;
1087         u8 *data;
1088         int size, i, pc;
1089         unsigned long irq_flags;
1090         struct ftrace_event_call *call = &tp->call;
1091
1092         local_save_flags(irq_flags);
1093         pc = preempt_count();
1094
1095         size = sizeof(*entry) + tp->size;
1096
1097         event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
1098                                                   irq_flags, pc);
1099         if (!event)
1100                 return;
1101
1102         entry = ring_buffer_event_data(event);
1103         entry->func = (unsigned long)tp->rp.kp.addr;
1104         entry->ret_ip = (unsigned long)ri->ret_addr;
1105         data = (u8 *)&entry[1];
1106         for (i = 0; i < tp->nr_args; i++)
1107                 call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);
1108
1109         if (!filter_current_check_discard(buffer, call, entry, event))
1110                 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
1111 }
1112
1113 /* Event entry printers */
1114 enum print_line_t
1115 print_kprobe_event(struct trace_iterator *iter, int flags)
1116 {
1117         struct kprobe_trace_entry_head *field;
1118         struct trace_seq *s = &iter->seq;
1119         struct trace_event *event;
1120         struct trace_probe *tp;
1121         u8 *data;
1122         int i;
1123
1124         field = (struct kprobe_trace_entry_head *)iter->ent;
1125         event = ftrace_find_event(field->ent.type);
1126         tp = container_of(event, struct trace_probe, 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 {
1154         struct kretprobe_trace_entry_head *field;
1155         struct trace_seq *s = &iter->seq;
1156         struct trace_event *event;
1157         struct trace_probe *tp;
1158         u8 *data;
1159         int i;
1160
1161         field = (struct kretprobe_trace_entry_head *)iter->ent;
1162         event = ftrace_find_event(field->ent.type);
1163         tp = container_of(event, struct trace_probe, event);
1164
1165         if (!trace_seq_printf(s, "%s: (", tp->call.name))
1166                 goto partial;
1167
1168         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1169                 goto partial;
1170
1171         if (!trace_seq_puts(s, " <- "))
1172                 goto partial;
1173
1174         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1175                 goto partial;
1176
1177         if (!trace_seq_puts(s, ")"))
1178                 goto partial;
1179
1180         data = (u8 *)&field[1];
1181         for (i = 0; i < tp->nr_args; i++)
1182                 if (!tp->args[i].type->print(s, tp->args[i].name,
1183                                              data + tp->args[i].offset))
1184                         goto partial;
1185
1186         if (!trace_seq_puts(s, "\n"))
1187                 goto partial;
1188
1189         return TRACE_TYPE_HANDLED;
1190 partial:
1191         return TRACE_TYPE_PARTIAL_LINE;
1192 }
1193
1194 static int probe_event_enable(struct ftrace_event_call *call)
1195 {
1196         struct trace_probe *tp = (struct trace_probe *)call->data;
1197
1198         tp->flags |= TP_FLAG_TRACE;
1199         if (probe_is_return(tp))
1200                 return enable_kretprobe(&tp->rp);
1201         else
1202                 return enable_kprobe(&tp->rp.kp);
1203 }
1204
1205 static void probe_event_disable(struct ftrace_event_call *call)
1206 {
1207         struct trace_probe *tp = (struct trace_probe *)call->data;
1208
1209         tp->flags &= ~TP_FLAG_TRACE;
1210         if (!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE))) {
1211                 if (probe_is_return(tp))
1212                         disable_kretprobe(&tp->rp);
1213                 else
1214                         disable_kprobe(&tp->rp.kp);
1215         }
1216 }
1217
1218 static int probe_event_raw_init(struct ftrace_event_call *event_call)
1219 {
1220         INIT_LIST_HEAD(&event_call->fields);
1221
1222         return 0;
1223 }
1224
1225 #undef DEFINE_FIELD
1226 #define DEFINE_FIELD(type, item, name, is_signed)                       \
1227         do {                                                            \
1228                 ret = trace_define_field(event_call, #type, name,       \
1229                                          offsetof(typeof(field), item), \
1230                                          sizeof(field.item), is_signed, \
1231                                          FILTER_OTHER);                 \
1232                 if (ret)                                                \
1233                         return ret;                                     \
1234         } while (0)
1235
1236 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1237 {
1238         int ret, i;
1239         struct kprobe_trace_entry_head field;
1240         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1241
1242         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1243         /* Set argument names as fields */
1244         for (i = 0; i < tp->nr_args; i++) {
1245                 ret = trace_define_field(event_call, tp->args[i].type->name,
1246                                          tp->args[i].name,
1247                                          sizeof(field) + tp->args[i].offset,
1248                                          tp->args[i].type->size,
1249                                          tp->args[i].type->is_signed,
1250                                          FILTER_OTHER);
1251                 if (ret)
1252                         return ret;
1253         }
1254         return 0;
1255 }
1256
1257 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1258 {
1259         int ret, i;
1260         struct kretprobe_trace_entry_head field;
1261         struct trace_probe *tp = (struct trace_probe *)event_call->data;
1262
1263         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1264         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1265         /* Set argument names as fields */
1266         for (i = 0; i < tp->nr_args; i++) {
1267                 ret = trace_define_field(event_call, tp->args[i].type->name,
1268                                          tp->args[i].name,
1269                                          sizeof(field) + tp->args[i].offset,
1270                                          tp->args[i].type->size,
1271                                          tp->args[i].type->is_signed,
1272                                          FILTER_OTHER);
1273                 if (ret)
1274                         return ret;
1275         }
1276         return 0;
1277 }
1278
1279 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len)
1280 {
1281         int i;
1282         int pos = 0;
1283
1284         const char *fmt, *arg;
1285
1286         if (!probe_is_return(tp)) {
1287                 fmt = "(%lx)";
1288                 arg = "REC->" FIELD_STRING_IP;
1289         } else {
1290                 fmt = "(%lx <- %lx)";
1291                 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1292         }
1293
1294         /* When len=0, we just calculate the needed length */
1295 #define LEN_OR_ZERO (len ? len - pos : 0)
1296
1297         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1298
1299         for (i = 0; i < tp->nr_args; i++) {
1300                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
1301                                 tp->args[i].name, tp->args[i].type->fmt);
1302         }
1303
1304         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
1305
1306         for (i = 0; i < tp->nr_args; i++) {
1307                 pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
1308                                 tp->args[i].name);
1309         }
1310
1311 #undef LEN_OR_ZERO
1312
1313         /* return the length of print_fmt */
1314         return pos;
1315 }
1316
1317 static int set_print_fmt(struct trace_probe *tp)
1318 {
1319         int len;
1320         char *print_fmt;
1321
1322         /* First: called with 0 length to calculate the needed length */
1323         len = __set_print_fmt(tp, NULL, 0);
1324         print_fmt = kmalloc(len + 1, GFP_KERNEL);
1325         if (!print_fmt)
1326                 return -ENOMEM;
1327
1328         /* Second: actually write the @print_fmt */
1329         __set_print_fmt(tp, print_fmt, len + 1);
1330         tp->call.print_fmt = print_fmt;
1331
1332         return 0;
1333 }
1334
1335 #ifdef CONFIG_PERF_EVENTS
1336
1337 /* Kprobe profile handler */
1338 static __kprobes void kprobe_perf_func(struct kprobe *kp,
1339                                          struct pt_regs *regs)
1340 {
1341         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1342         struct ftrace_event_call *call = &tp->call;
1343         struct kprobe_trace_entry_head *entry;
1344         u8 *data;
1345         int size, __size, i;
1346         unsigned long irq_flags;
1347         int rctx;
1348
1349         __size = sizeof(*entry) + tp->size;
1350         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1351         size -= sizeof(u32);
1352         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1353                      "profile buffer not large enough"))
1354                 return;
1355
1356         entry = perf_trace_buf_prepare(size, call->id, &rctx, &irq_flags);
1357         if (!entry)
1358                 return;
1359
1360         entry->ip = (unsigned long)kp->addr;
1361         data = (u8 *)&entry[1];
1362         for (i = 0; i < tp->nr_args; i++)
1363                 call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);
1364
1365         perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, irq_flags, regs);
1366 }
1367
1368 /* Kretprobe profile handler */
1369 static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
1370                                             struct pt_regs *regs)
1371 {
1372         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1373         struct ftrace_event_call *call = &tp->call;
1374         struct kretprobe_trace_entry_head *entry;
1375         u8 *data;
1376         int size, __size, i;
1377         unsigned long irq_flags;
1378         int rctx;
1379
1380         __size = sizeof(*entry) + tp->size;
1381         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1382         size -= sizeof(u32);
1383         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1384                      "profile buffer not large enough"))
1385                 return;
1386
1387         entry = perf_trace_buf_prepare(size, call->id, &rctx, &irq_flags);
1388         if (!entry)
1389                 return;
1390
1391         entry->func = (unsigned long)tp->rp.kp.addr;
1392         entry->ret_ip = (unsigned long)ri->ret_addr;
1393         data = (u8 *)&entry[1];
1394         for (i = 0; i < tp->nr_args; i++)
1395                 call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);
1396
1397         perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1,
1398                                irq_flags, regs);
1399 }
1400
1401 static int probe_perf_enable(struct ftrace_event_call *call)
1402 {
1403         struct trace_probe *tp = (struct trace_probe *)call->data;
1404
1405         tp->flags |= TP_FLAG_PROFILE;
1406
1407         if (probe_is_return(tp))
1408                 return enable_kretprobe(&tp->rp);
1409         else
1410                 return enable_kprobe(&tp->rp.kp);
1411 }
1412
1413 static void probe_perf_disable(struct ftrace_event_call *call)
1414 {
1415         struct trace_probe *tp = (struct trace_probe *)call->data;
1416
1417         tp->flags &= ~TP_FLAG_PROFILE;
1418
1419         if (!(tp->flags & TP_FLAG_TRACE)) {
1420                 if (probe_is_return(tp))
1421                         disable_kretprobe(&tp->rp);
1422                 else
1423                         disable_kprobe(&tp->rp.kp);
1424         }
1425 }
1426 #endif  /* CONFIG_PERF_EVENTS */
1427
1428
1429 static __kprobes
1430 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1431 {
1432         struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1433
1434         if (tp->flags & TP_FLAG_TRACE)
1435                 kprobe_trace_func(kp, regs);
1436 #ifdef CONFIG_PERF_EVENTS
1437         if (tp->flags & TP_FLAG_PROFILE)
1438                 kprobe_perf_func(kp, regs);
1439 #endif
1440         return 0;       /* We don't tweek kernel, so just return 0 */
1441 }
1442
1443 static __kprobes
1444 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1445 {
1446         struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1447
1448         if (tp->flags & TP_FLAG_TRACE)
1449                 kretprobe_trace_func(ri, regs);
1450 #ifdef CONFIG_PERF_EVENTS
1451         if (tp->flags & TP_FLAG_PROFILE)
1452                 kretprobe_perf_func(ri, regs);
1453 #endif
1454         return 0;       /* We don't tweek kernel, so just return 0 */
1455 }
1456
1457 static int register_probe_event(struct trace_probe *tp)
1458 {
1459         struct ftrace_event_call *call = &tp->call;
1460         int ret;
1461
1462         /* Initialize ftrace_event_call */
1463         if (probe_is_return(tp)) {
1464                 tp->event.trace = print_kretprobe_event;
1465                 call->raw_init = probe_event_raw_init;
1466                 call->define_fields = kretprobe_event_define_fields;
1467         } else {
1468                 tp->event.trace = print_kprobe_event;
1469                 call->raw_init = probe_event_raw_init;
1470                 call->define_fields = kprobe_event_define_fields;
1471         }
1472         if (set_print_fmt(tp) < 0)
1473                 return -ENOMEM;
1474         call->event = &tp->event;
1475         call->id = register_ftrace_event(&tp->event);
1476         if (!call->id) {
1477                 kfree(call->print_fmt);
1478                 return -ENODEV;
1479         }
1480         call->enabled = 0;
1481         call->regfunc = probe_event_enable;
1482         call->unregfunc = probe_event_disable;
1483
1484 #ifdef CONFIG_PERF_EVENTS
1485         call->perf_event_enable = probe_perf_enable;
1486         call->perf_event_disable = probe_perf_disable;
1487 #endif
1488         call->data = tp;
1489         ret = trace_add_event_call(call);
1490         if (ret) {
1491                 pr_info("Failed to register kprobe event: %s\n", call->name);
1492                 kfree(call->print_fmt);
1493                 unregister_ftrace_event(&tp->event);
1494         }
1495         return ret;
1496 }
1497
1498 static void unregister_probe_event(struct trace_probe *tp)
1499 {
1500         /* tp->event is unregistered in trace_remove_event_call() */
1501         trace_remove_event_call(&tp->call);
1502         kfree(tp->call.print_fmt);
1503 }
1504
1505 /* Make a debugfs interface for controling probe points */
1506 static __init int init_kprobe_trace(void)
1507 {
1508         struct dentry *d_tracer;
1509         struct dentry *entry;
1510
1511         d_tracer = tracing_init_dentry();
1512         if (!d_tracer)
1513                 return 0;
1514
1515         entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1516                                     NULL, &kprobe_events_ops);
1517
1518         /* Event list interface */
1519         if (!entry)
1520                 pr_warning("Could not create debugfs "
1521                            "'kprobe_events' entry\n");
1522
1523         /* Profile interface */
1524         entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1525                                     NULL, &kprobe_profile_ops);
1526
1527         if (!entry)
1528                 pr_warning("Could not create debugfs "
1529                            "'kprobe_profile' entry\n");
1530         return 0;
1531 }
1532 fs_initcall(init_kprobe_trace);
1533
1534
1535 #ifdef CONFIG_FTRACE_STARTUP_TEST
1536
1537 static int kprobe_trace_selftest_target(int a1, int a2, int a3,
1538                                         int a4, int a5, int a6)
1539 {
1540         return a1 + a2 + a3 + a4 + a5 + a6;
1541 }
1542
1543 static __init int kprobe_trace_self_tests_init(void)
1544 {
1545         int ret, warn = 0;
1546         int (*target)(int, int, int, int, int, int);
1547         struct trace_probe *tp;
1548
1549         target = kprobe_trace_selftest_target;
1550
1551         pr_info("Testing kprobe tracing: ");
1552
1553         ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
1554                                   "$stack $stack0 +0($stack)");
1555         if (WARN_ON_ONCE(ret)) {
1556                 pr_warning("error on probing function entry.\n");
1557                 warn++;
1558         } else {
1559                 /* Enable trace point */
1560                 tp = find_probe_event("testprobe", KPROBE_EVENT_SYSTEM);
1561                 if (WARN_ON_ONCE(tp == NULL)) {
1562                         pr_warning("error on getting new probe.\n");
1563                         warn++;
1564                 } else
1565                         probe_event_enable(&tp->call);
1566         }
1567
1568         ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
1569                                   "$retval");
1570         if (WARN_ON_ONCE(ret)) {
1571                 pr_warning("error on probing function return.\n");
1572                 warn++;
1573         } else {
1574                 /* Enable trace point */
1575                 tp = find_probe_event("testprobe2", KPROBE_EVENT_SYSTEM);
1576                 if (WARN_ON_ONCE(tp == NULL)) {
1577                         pr_warning("error on getting new probe.\n");
1578                         warn++;
1579                 } else
1580                         probe_event_enable(&tp->call);
1581         }
1582
1583         if (warn)
1584                 goto end;
1585
1586         ret = target(1, 2, 3, 4, 5, 6);
1587
1588         ret = command_trace_probe("-:testprobe");
1589         if (WARN_ON_ONCE(ret)) {
1590                 pr_warning("error on deleting a probe.\n");
1591                 warn++;
1592         }
1593
1594         ret = command_trace_probe("-:testprobe2");
1595         if (WARN_ON_ONCE(ret)) {
1596                 pr_warning("error on deleting a probe.\n");
1597                 warn++;
1598         }
1599
1600 end:
1601         cleanup_all_probes();
1602         if (warn)
1603                 pr_cont("NG: Some tests are failed. Please check them.\n");
1604         else
1605                 pr_cont("OK\n");
1606         return 0;
1607 }
1608
1609 late_initcall(kprobe_trace_self_tests_init);
1610
1611 #endif