kernel/trace/trace_kprobe.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Kprobes-based tracing events
   4  *
   5  * Created by Masami Hiramatsu <mhiramat@redhat.com>
   6  *
   7  */
   8 #define pr_fmt(fmt)     "trace_kprobe: " fmt
   9
  10 #include <linux/module.h>
  11 #include <linux/uaccess.h>
  12 #include <linux/rculist.h>
  13 #include <linux/error-injection.h>
  14
  15 #include "trace_dynevent.h"
  16 #include "trace_kprobe_selftest.h"
  17 #include "trace_probe.h"
  18 #include "trace_probe_tmpl.h"
  19
  20 #define KPROBE_EVENT_SYSTEM "kprobes"
  21 #define KRETPROBE_MAXACTIVE_MAX 4096
  22
  23 static int trace_kprobe_create(int argc, const char **argv);
  24 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
  25 static int trace_kprobe_release(struct dyn_event *ev);
  26 static bool trace_kprobe_is_busy(struct dyn_event *ev);
  27 static bool trace_kprobe_match(const char *system, const char *event,
  28                                struct dyn_event *ev);
  29
  30 static struct dyn_event_operations trace_kprobe_ops = {
  31         .create = trace_kprobe_create,
  32         .show = trace_kprobe_show,
  33         .is_busy = trace_kprobe_is_busy,
  34         .free = trace_kprobe_release,
  35         .match = trace_kprobe_match,
  36 };
  37
  38 /**
  39  * Kprobe event core functions
  40  */
  41 struct trace_kprobe {
  42         struct dyn_event        devent;
  43         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
  44         unsigned long __percpu *nhit;
  45         const char              *symbol;        /* symbol name */
  46         struct trace_probe      tp;
  47 };
  48
  49 static bool is_trace_kprobe(struct dyn_event *ev)
  50 {
  51         return ev->ops == &trace_kprobe_ops;
  52 }
  53
  54 static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
  55 {
  56         return container_of(ev, struct trace_kprobe, devent);
  57 }
  58
  59 /**
  60  * for_each_trace_kprobe - iterate over the trace_kprobe list
  61  * @pos:        the struct trace_kprobe * for each entry
  62  * @dpos:       the struct dyn_event * to use as a loop cursor
  63  */
  64 #define for_each_trace_kprobe(pos, dpos)        \
  65         for_each_dyn_event(dpos)                \
  66                 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
  67
  68 #define SIZEOF_TRACE_KPROBE(n)                          \
  69         (offsetof(struct trace_kprobe, tp.args) +       \
  70         (sizeof(struct probe_arg) * (n)))
  71
  72 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
  73 {
  74         return tk->rp.handler != NULL;
  75 }
  76
  77 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
  78 {
  79         return tk->symbol ? tk->symbol : "unknown";
  80 }
  81
  82 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
  83 {
  84         return tk->rp.kp.offset;
  85 }
  86
  87 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
  88 {
  89         return !!(kprobe_gone(&tk->rp.kp));
  90 }
  91
  92 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
  93                                                  struct module *mod)
  94 {
  95         int len = strlen(mod->name);
  96         const char *name = trace_kprobe_symbol(tk);
  97         return strncmp(mod->name, name, len) == 0 && name[len] == ':';
  98 }
  99
 100 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
 101 {
 102         char *p;
 103         bool ret;
 104
 105         if (!tk->symbol)
 106                 return false;
 107         p = strchr(tk->symbol, ':');
 108         if (!p)
 109                 return true;
 110         *p = '\0';
 111         mutex_lock(&module_mutex);
 112         ret = !!find_module(tk->symbol);
 113         mutex_unlock(&module_mutex);
 114         *p = ':';
 115
 116         return ret;
 117 }
 118
 119 static bool trace_kprobe_is_busy(struct dyn_event *ev)
 120 {
 121         struct trace_kprobe *tk = to_trace_kprobe(ev);
 122
 123         return trace_probe_is_enabled(&tk->tp);
 124 }
 125
 126 static bool trace_kprobe_match(const char *system, const char *event,
 127                                struct dyn_event *ev)
 128 {
 129         struct trace_kprobe *tk = to_trace_kprobe(ev);
 130
 131         return strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
 132             (!system || strcmp(tk->tp.call.class->system, system) == 0);
 133 }
 134
 135 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
 136 {
 137         unsigned long nhit = 0;
 138         int cpu;
 139
 140         for_each_possible_cpu(cpu)
 141                 nhit += *per_cpu_ptr(tk->nhit, cpu);
 142
 143         return nhit;
 144 }
 145
 146 /* Return 0 if it fails to find the symbol address */
 147 static nokprobe_inline
 148 unsigned long trace_kprobe_address(struct trace_kprobe *tk)
 149 {
 150         unsigned long addr;
 151
 152         if (tk->symbol) {
 153                 addr = (unsigned long)
 154                         kallsyms_lookup_name(trace_kprobe_symbol(tk));
 155                 if (addr)
 156                         addr += tk->rp.kp.offset;
 157         } else {
 158                 addr = (unsigned long)tk->rp.kp.addr;
 159         }
 160         return addr;
 161 }
 162
 163 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
 164 {
 165         struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
 166
 167         return kprobe_on_func_entry(tk->rp.kp.addr,
 168                         tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
 169                         tk->rp.kp.addr ? 0 : tk->rp.kp.offset);
 170 }
 171
 172 bool trace_kprobe_error_injectable(struct trace_event_call *call)
 173 {
 174         struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
 175
 176         return within_error_injection_list(trace_kprobe_address(tk));
 177 }
 178
 179 static int register_kprobe_event(struct trace_kprobe *tk);
 180 static int unregister_kprobe_event(struct trace_kprobe *tk);
 181
 182 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 183 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 184                                 struct pt_regs *regs);
 185
 186 /*
 187  * Allocate new trace_probe and initialize it (including kprobes).
 188  */
 189 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
 190                                              const char *event,
 191                                              void *addr,
 192                                              const char *symbol,
 193                                              unsigned long offs,
 194                                              int maxactive,
 195                                              int nargs, bool is_return)
 196 {
 197         struct trace_kprobe *tk;
 198         int ret = -ENOMEM;
 199
 200         tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
 201         if (!tk)
 202                 return ERR_PTR(ret);
 203
 204         tk->nhit = alloc_percpu(unsigned long);
 205         if (!tk->nhit)
 206                 goto error;
 207
 208         if (symbol) {
 209                 tk->symbol = kstrdup(symbol, GFP_KERNEL);
 210                 if (!tk->symbol)
 211                         goto error;
 212                 tk->rp.kp.symbol_name = tk->symbol;
 213                 tk->rp.kp.offset = offs;
 214         } else
 215                 tk->rp.kp.addr = addr;
 216
 217         if (is_return)
 218                 tk->rp.handler = kretprobe_dispatcher;
 219         else
 220                 tk->rp.kp.pre_handler = kprobe_dispatcher;
 221
 222         tk->rp.maxactive = maxactive;
 223
 224         if (!event || !is_good_name(event)) {
 225                 ret = -EINVAL;
 226                 goto error;
 227         }
 228
 229         tk->tp.call.class = &tk->tp.class;
 230         tk->tp.call.name = kstrdup(event, GFP_KERNEL);
 231         if (!tk->tp.call.name)
 232                 goto error;
 233
 234         if (!group || !is_good_name(group)) {
 235                 ret = -EINVAL;
 236                 goto error;
 237         }
 238
 239         tk->tp.class.system = kstrdup(group, GFP_KERNEL);
 240         if (!tk->tp.class.system)
 241                 goto error;
 242
 243         dyn_event_init(&tk->devent, &trace_kprobe_ops);
 244         INIT_LIST_HEAD(&tk->tp.files);
 245         return tk;
 246 error:
 247         kfree(tk->tp.call.name);
 248         kfree(tk->symbol);
 249         free_percpu(tk->nhit);
 250         kfree(tk);
 251         return ERR_PTR(ret);
 252 }
 253
 254 static void free_trace_kprobe(struct trace_kprobe *tk)
 255 {
 256         int i;
 257
 258         if (!tk)
 259                 return;
 260
 261         for (i = 0; i < tk->tp.nr_args; i++)
 262                 traceprobe_free_probe_arg(&tk->tp.args[i]);
 263
 264         kfree(tk->tp.call.class->system);
 265         kfree(tk->tp.call.name);
 266         kfree(tk->symbol);
 267         free_percpu(tk->nhit);
 268         kfree(tk);
 269 }
 270
 271 static struct trace_kprobe *find_trace_kprobe(const char *event,
 272                                               const char *group)
 273 {
 274         struct dyn_event *pos;
 275         struct trace_kprobe *tk;
 276
 277         for_each_trace_kprobe(tk, pos)
 278                 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
 279                     strcmp(tk->tp.call.class->system, group) == 0)
 280                         return tk;
 281         return NULL;
 282 }
 283
 284 static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
 285 {
 286         int ret = 0;
 287
 288         if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
 289                 if (trace_kprobe_is_return(tk))
 290                         ret = enable_kretprobe(&tk->rp);
 291                 else
 292                         ret = enable_kprobe(&tk->rp.kp);
 293         }
 294
 295         return ret;
 296 }
 297
 298 /*
 299  * Enable trace_probe
 300  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
 301  */
 302 static int
 303 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 304 {
 305         struct event_file_link *link;
 306         int ret = 0;
 307
 308         if (file) {
 309                 link = kmalloc(sizeof(*link), GFP_KERNEL);
 310                 if (!link) {
 311                         ret = -ENOMEM;
 312                         goto out;
 313                 }
 314
 315                 link->file = file;
 316                 list_add_tail_rcu(&link->list, &tk->tp.files);
 317
 318                 tk->tp.flags |= TP_FLAG_TRACE;
 319                 ret = __enable_trace_kprobe(tk);
 320                 if (ret) {
 321                         list_del_rcu(&link->list);
 322                         kfree(link);
 323                         tk->tp.flags &= ~TP_FLAG_TRACE;
 324                 }
 325
 326         } else {
 327                 tk->tp.flags |= TP_FLAG_PROFILE;
 328                 ret = __enable_trace_kprobe(tk);
 329                 if (ret)
 330                         tk->tp.flags &= ~TP_FLAG_PROFILE;
 331         }
 332  out:
 333         return ret;
 334 }
 335
 336 /*
 337  * Disable trace_probe
 338  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
 339  */
 340 static int
 341 disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 342 {
 343         struct event_file_link *link = NULL;
 344         int wait = 0;
 345         int ret = 0;
 346
 347         if (file) {
 348                 link = find_event_file_link(&tk->tp, file);
 349                 if (!link) {
 350                         ret = -EINVAL;
 351                         goto out;
 352                 }
 353
 354                 list_del_rcu(&link->list);
 355                 wait = 1;
 356                 if (!list_empty(&tk->tp.files))
 357                         goto out;
 358
 359                 tk->tp.flags &= ~TP_FLAG_TRACE;
 360         } else
 361                 tk->tp.flags &= ~TP_FLAG_PROFILE;
 362
 363         if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
 364                 if (trace_kprobe_is_return(tk))
 365                         disable_kretprobe(&tk->rp);
 366                 else
 367                         disable_kprobe(&tk->rp.kp);
 368                 wait = 1;
 369         }
 370
 371         /*
 372          * if tk is not added to any list, it must be a local trace_kprobe
 373          * created with perf_event_open. We don't need to wait for these
 374          * trace_kprobes
 375          */
 376         if (list_empty(&tk->devent.list))
 377                 wait = 0;
 378  out:
 379         if (wait) {
 380                 /*
 381                  * Synchronize with kprobe_trace_func/kretprobe_trace_func
 382                  * to ensure disabled (all running handlers are finished).
 383                  * This is not only for kfree(), but also the caller,
 384                  * trace_remove_event_call() supposes it for releasing
 385                  * event_call related objects, which will be accessed in
 386                  * the kprobe_trace_func/kretprobe_trace_func.
 387                  */
 388                 synchronize_rcu();
 389                 kfree(link);    /* Ignored if link == NULL */
 390         }
 391
 392         return ret;
 393 }
 394
 395 #if defined(CONFIG_KPROBES_ON_FTRACE) && \
 396         !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
 397 static bool within_notrace_func(struct trace_kprobe *tk)
 398 {
 399         unsigned long offset, size, addr;
 400
 401         addr = trace_kprobe_address(tk);
 402         if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
 403                 return false;
 404
 405         /* Get the entry address of the target function */
 406         addr -= offset;
 407
 408         /*
 409          * Since ftrace_location_range() does inclusive range check, we need
 410          * to subtract 1 byte from the end address.
 411          */
 412         return !ftrace_location_range(addr, addr + size - 1);
 413 }
 414 #else
 415 #define within_notrace_func(tk) (false)
 416 #endif
 417
 418 /* Internal register function - just handle k*probes and flags */
 419 static int __register_trace_kprobe(struct trace_kprobe *tk)
 420 {
 421         int i, ret;
 422
 423         if (trace_probe_is_registered(&tk->tp))
 424                 return -EINVAL;
 425
 426         if (within_notrace_func(tk)) {
 427                 pr_warn("Could not probe notrace function %s\n",
 428                         trace_kprobe_symbol(tk));
 429                 return -EINVAL;
 430         }
 431
 432         for (i = 0; i < tk->tp.nr_args; i++) {
 433                 ret = traceprobe_update_arg(&tk->tp.args[i]);
 434                 if (ret)
 435                         return ret;
 436         }
 437
 438         /* Set/clear disabled flag according to tp->flag */
 439         if (trace_probe_is_enabled(&tk->tp))
 440                 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
 441         else
 442                 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 443
 444         if (trace_kprobe_is_return(tk))
 445                 ret = register_kretprobe(&tk->rp);
 446         else
 447                 ret = register_kprobe(&tk->rp.kp);
 448
 449         if (ret == 0) {
 450                 tk->tp.flags |= TP_FLAG_REGISTERED;
 451         } else if (ret == -EILSEQ) {
 452                 pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
 453                         tk->rp.kp.addr);
 454                 ret = -EINVAL;
 455         }
 456         return ret;
 457 }
 458
 459 /* Internal unregister function - just handle k*probes and flags */
 460 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 461 {
 462         if (trace_probe_is_registered(&tk->tp)) {
 463                 if (trace_kprobe_is_return(tk))
 464                         unregister_kretprobe(&tk->rp);
 465                 else
 466                         unregister_kprobe(&tk->rp.kp);
 467                 tk->tp.flags &= ~TP_FLAG_REGISTERED;
 468                 /* Cleanup kprobe for reuse */
 469                 if (tk->rp.kp.symbol_name)
 470                         tk->rp.kp.addr = NULL;
 471         }
 472 }
 473
 474 /* Unregister a trace_probe and probe_event */
 475 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 476 {
 477         /* Enabled event can not be unregistered */
 478         if (trace_probe_is_enabled(&tk->tp))
 479                 return -EBUSY;
 480
 481         /* Will fail if probe is being used by ftrace or perf */
 482         if (unregister_kprobe_event(tk))
 483                 return -EBUSY;
 484
 485         __unregister_trace_kprobe(tk);
 486         dyn_event_remove(&tk->devent);
 487
 488         return 0;
 489 }
 490
 491 /* Register a trace_probe and probe_event */
 492 static int register_trace_kprobe(struct trace_kprobe *tk)
 493 {
 494         struct trace_kprobe *old_tk;
 495         int ret;
 496
 497         mutex_lock(&event_mutex);
 498
 499         /* Delete old (same name) event if exist */
 500         old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
 501                         tk->tp.call.class->system);
 502         if (old_tk) {
 503                 ret = unregister_trace_kprobe(old_tk);
 504                 if (ret < 0)
 505                         goto end;
 506                 free_trace_kprobe(old_tk);
 507         }
 508
 509         /* Register new event */
 510         ret = register_kprobe_event(tk);
 511         if (ret) {
 512                 pr_warn("Failed to register probe event(%d)\n", ret);
 513                 goto end;
 514         }
 515
 516         /* Register k*probe */
 517         ret = __register_trace_kprobe(tk);
 518         if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
 519                 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 520                 ret = 0;
 521         }
 522
 523         if (ret < 0)
 524                 unregister_kprobe_event(tk);
 525         else
 526                 dyn_event_add(&tk->devent);
 527
 528 end:
 529         mutex_unlock(&event_mutex);
 530         return ret;
 531 }
 532
 533 /* Module notifier call back, checking event on the module */
 534 static int trace_kprobe_module_callback(struct notifier_block *nb,
 535                                        unsigned long val, void *data)
 536 {
 537         struct module *mod = data;
 538         struct dyn_event *pos;
 539         struct trace_kprobe *tk;
 540         int ret;
 541
 542         if (val != MODULE_STATE_COMING)
 543                 return NOTIFY_DONE;
 544
 545         /* Update probes on coming module */
 546         mutex_lock(&event_mutex);
 547         for_each_trace_kprobe(tk, pos) {
 548                 if (trace_kprobe_within_module(tk, mod)) {
 549                         /* Don't need to check busy - this should have gone. */
 550                         __unregister_trace_kprobe(tk);
 551                         ret = __register_trace_kprobe(tk);
 552                         if (ret)
 553                                 pr_warn("Failed to re-register probe %s on %s: %d\n",
 554                                         trace_event_name(&tk->tp.call),
 555                                         mod->name, ret);
 556                 }
 557         }
 558         mutex_unlock(&event_mutex);
 559
 560         return NOTIFY_DONE;
 561 }
 562
 563 static struct notifier_block trace_kprobe_module_nb = {
 564         .notifier_call = trace_kprobe_module_callback,
 565         .priority = 1   /* Invoked after kprobe module callback */
 566 };
 567
 568 /* Convert certain expected symbols into '_' when generating event names */
 569 static inline void sanitize_event_name(char *name)
 570 {
 571         while (*name++ != '\0')
 572                 if (*name == ':' || *name == '.')
 573                         *name = '_';
 574 }
 575
 576 static int trace_kprobe_create(int argc, const char *argv[])
 577 {
 578         /*
 579          * Argument syntax:
 580          *  - Add kprobe:
 581          *      p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 582          *  - Add kretprobe:
 583          *      r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
 584          * Fetch args:
 585          *  $retval     : fetch return value
 586          *  $stack      : fetch stack address
 587          *  $stackN     : fetch Nth of stack (N:0-)
 588          *  $comm       : fetch current task comm
 589          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 590          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 591          *  %REG        : fetch register REG
 592          * Dereferencing memory fetch:
 593          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 594          * Alias name of args:
 595          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 596          * Type of args:
 597          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 598          */
 599         struct trace_kprobe *tk;
 600         int i, len, ret = 0;
 601         bool is_return = false;
 602         char *symbol = NULL, *tmp = NULL;
 603         const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
 604         int maxactive = 0;
 605         long offset = 0;
 606         void *addr = NULL;
 607         char buf[MAX_EVENT_NAME_LEN];
 608         unsigned int flags = TPARG_FL_KERNEL;
 609
 610         switch (argv[0][0]) {
 611         case 'r':
 612                 is_return = true;
 613                 flags |= TPARG_FL_RETURN;
 614                 break;
 615         case 'p':
 616                 break;
 617         default:
 618                 return -ECANCELED;
 619         }
 620         if (argc < 2)
 621                 return -ECANCELED;
 622
 623         event = strchr(&argv[0][1], ':');
 624         if (event)
 625                 event++;
 626
 627         if (is_return && isdigit(argv[0][1])) {
 628                 if (event)
 629                         len = event - &argv[0][1] - 1;
 630                 else
 631                         len = strlen(&argv[0][1]);
 632                 if (len > MAX_EVENT_NAME_LEN - 1)
 633                         return -E2BIG;
 634                 memcpy(buf, &argv[0][1], len);
 635                 buf[len] = '\0';
 636                 ret = kstrtouint(buf, 0, &maxactive);
 637                 if (ret) {
 638                         pr_info("Failed to parse maxactive.\n");
 639                         return ret;
 640                 }
 641                 /* kretprobes instances are iterated over via a list. The
 642                  * maximum should stay reasonable.
 643                  */
 644                 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
 645                         pr_info("Maxactive is too big (%d > %d).\n",
 646                                 maxactive, KRETPROBE_MAXACTIVE_MAX);
 647                         return -E2BIG;
 648                 }
 649         }
 650
 651         /* try to parse an address. if that fails, try to read the
 652          * input as a symbol. */
 653         if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
 654                 /* Check whether uprobe event specified */
 655                 if (strchr(argv[1], '/') && strchr(argv[1], ':'))
 656                         return -ECANCELED;
 657                 /* a symbol specified */
 658                 symbol = kstrdup(argv[1], GFP_KERNEL);
 659                 if (!symbol)
 660                         return -ENOMEM;
 661                 /* TODO: support .init module functions */
 662                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 663                 if (ret || offset < 0 || offset > UINT_MAX) {
 664                         pr_info("Failed to parse either an address or a symbol.\n");
 665                         goto out;
 666                 }
 667                 if (kprobe_on_func_entry(NULL, symbol, offset))
 668                         flags |= TPARG_FL_FENTRY;
 669                 if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {
 670                         pr_info("Given offset is not valid for return probe.\n");
 671                         ret = -EINVAL;
 672                         goto out;
 673                 }
 674         }
 675         argc -= 2; argv += 2;
 676
 677         if (event) {
 678                 ret = traceprobe_parse_event_name(&event, &group, buf);
 679                 if (ret)
 680                         goto out;
 681         } else {
 682                 /* Make a new event name */
 683                 if (symbol)
 684                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 685                                  is_return ? 'r' : 'p', symbol, offset);
 686                 else
 687                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 688                                  is_return ? 'r' : 'p', addr);
 689                 sanitize_event_name(buf);
 690                 event = buf;
 691         }
 692
 693         /* setup a probe */
 694         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
 695                                argc, is_return);
 696         if (IS_ERR(tk)) {
 697                 pr_info("Failed to allocate trace_probe.(%d)\n",
 698                         (int)PTR_ERR(tk));
 699                 ret = PTR_ERR(tk);
 700                 goto out;
 701         }
 702
 703         /* parse arguments */
 704         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 705                 tmp = kstrdup(argv[i], GFP_KERNEL);
 706                 if (!tmp) {
 707                         ret = -ENOMEM;
 708                         goto error;
 709                 }
 710
 711                 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
 712                 kfree(tmp);
 713                 if (ret)
 714                         goto error;
 715         }
 716
 717         ret = register_trace_kprobe(tk);
 718         if (ret)
 719                 goto error;
 720 out:
 721         kfree(symbol);
 722         return ret;
 723
 724 error:
 725         free_trace_kprobe(tk);
 726         goto out;
 727 }
 728
 729 static int create_or_delete_trace_kprobe(int argc, char **argv)
 730 {
 731         int ret;
 732
 733         if (argv[0][0] == '-')
 734                 return dyn_event_release(argc, argv, &trace_kprobe_ops);
 735
 736         ret = trace_kprobe_create(argc, (const char **)argv);
 737         return ret == -ECANCELED ? -EINVAL : ret;
 738 }
 739
 740 static int trace_kprobe_release(struct dyn_event *ev)
 741 {
 742         struct trace_kprobe *tk = to_trace_kprobe(ev);
 743         int ret = unregister_trace_kprobe(tk);
 744
 745         if (!ret)
 746                 free_trace_kprobe(tk);
 747         return ret;
 748 }
 749
 750 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
 751 {
 752         struct trace_kprobe *tk = to_trace_kprobe(ev);
 753         int i;
 754
 755         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
 756         seq_printf(m, ":%s/%s", tk->tp.call.class->system,
 757                         trace_event_name(&tk->tp.call));
 758
 759         if (!tk->symbol)
 760                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
 761         else if (tk->rp.kp.offset)
 762                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
 763                            tk->rp.kp.offset);
 764         else
 765                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
 766
 767         for (i = 0; i < tk->tp.nr_args; i++)
 768                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
 769         seq_putc(m, '\n');
 770
 771         return 0;
 772 }
 773
 774 static int probes_seq_show(struct seq_file *m, void *v)
 775 {
 776         struct dyn_event *ev = v;
 777
 778         if (!is_trace_kprobe(ev))
 779                 return 0;
 780
 781         return trace_kprobe_show(m, ev);
 782 }
 783
 784 static const struct seq_operations probes_seq_op = {
 785         .start  = dyn_event_seq_start,
 786         .next   = dyn_event_seq_next,
 787         .stop   = dyn_event_seq_stop,
 788         .show   = probes_seq_show
 789 };
 790
 791 static int probes_open(struct inode *inode, struct file *file)
 792 {
 793         int ret;
 794
 795         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 796                 ret = dyn_events_release_all(&trace_kprobe_ops);
 797                 if (ret < 0)
 798                         return ret;
 799         }
 800
 801         return seq_open(file, &probes_seq_op);
 802 }
 803
 804 static ssize_t probes_write(struct file *file, const char __user *buffer,
 805                             size_t count, loff_t *ppos)
 806 {
 807         return trace_parse_run_command(file, buffer, count, ppos,
 808                                        create_or_delete_trace_kprobe);
 809 }
 810
 811 static const struct file_operations kprobe_events_ops = {
 812         .owner          = THIS_MODULE,
 813         .open           = probes_open,
 814         .read           = seq_read,
 815         .llseek         = seq_lseek,
 816         .release        = seq_release,
 817         .write          = probes_write,
 818 };
 819
 820 /* Probes profiling interfaces */
 821 static int probes_profile_seq_show(struct seq_file *m, void *v)
 822 {
 823         struct dyn_event *ev = v;
 824         struct trace_kprobe *tk;
 825
 826         if (!is_trace_kprobe(ev))
 827                 return 0;
 828
 829         tk = to_trace_kprobe(ev);
 830         seq_printf(m, "  %-44s %15lu %15lu\n",
 831                    trace_event_name(&tk->tp.call),
 832                    trace_kprobe_nhit(tk),
 833                    tk->rp.kp.nmissed);
 834
 835         return 0;
 836 }
 837
 838 static const struct seq_operations profile_seq_op = {
 839         .start  = dyn_event_seq_start,
 840         .next   = dyn_event_seq_next,
 841         .stop   = dyn_event_seq_stop,
 842         .show   = probes_profile_seq_show
 843 };
 844
 845 static int profile_open(struct inode *inode, struct file *file)
 846 {
 847         return seq_open(file, &profile_seq_op);
 848 }
 849
 850 static const struct file_operations kprobe_profile_ops = {
 851         .owner          = THIS_MODULE,
 852         .open           = profile_open,
 853         .read           = seq_read,
 854         .llseek         = seq_lseek,
 855         .release        = seq_release,
 856 };
 857
 858 /* Kprobe specific fetch functions */
 859
 860 /* Return the length of string -- including null terminal byte */
 861 static nokprobe_inline int
 862 fetch_store_strlen(unsigned long addr)
 863 {
 864         int ret, len = 0;
 865         u8 c;
 866
 867         do {
 868                 ret = probe_kernel_read(&c, (u8 *)addr + len, 1);
 869                 len++;
 870         } while (c && ret == 0 && len < MAX_STRING_SIZE);
 871
 872         return (ret < 0) ? ret : len;
 873 }
 874
 875 /*
 876  * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
 877  * length and relative data location.
 878  */
 879 static nokprobe_inline int
 880 fetch_store_string(unsigned long addr, void *dest, void *base)
 881 {
 882         int maxlen = get_loc_len(*(u32 *)dest);
 883         u8 *dst = get_loc_data(dest, base);
 884         long ret;
 885
 886         if (unlikely(!maxlen))
 887                 return -ENOMEM;
 888         /*
 889          * Try to get string again, since the string can be changed while
 890          * probing.
 891          */
 892         ret = strncpy_from_unsafe(dst, (void *)addr, maxlen);
 893
 894         if (ret >= 0)
 895                 *(u32 *)dest = make_data_loc(ret, (void *)dst - base);
 896         return ret;
 897 }
 898
 899 static nokprobe_inline int
 900 probe_mem_read(void *dest, void *src, size_t size)
 901 {
 902         return probe_kernel_read(dest, src, size);
 903 }
 904
 905 /* Note that we don't verify it, since the code does not come from user space */
 906 static int
 907 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
 908                    void *base)
 909 {
 910         unsigned long val;
 911
 912 retry:
 913         /* 1st stage: get value from context */
 914         switch (code->op) {
 915         case FETCH_OP_REG:
 916                 val = regs_get_register(regs, code->param);
 917                 break;
 918         case FETCH_OP_STACK:
 919                 val = regs_get_kernel_stack_nth(regs, code->param);
 920                 break;
 921         case FETCH_OP_STACKP:
 922                 val = kernel_stack_pointer(regs);
 923                 break;
 924         case FETCH_OP_RETVAL:
 925                 val = regs_return_value(regs);
 926                 break;
 927         case FETCH_OP_IMM:
 928                 val = code->immediate;
 929                 break;
 930         case FETCH_OP_COMM:
 931                 val = (unsigned long)current->comm;
 932                 break;
 933 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
 934         case FETCH_OP_ARG:
 935                 val = regs_get_kernel_argument(regs, code->param);
 936                 break;
 937 #endif
 938         case FETCH_NOP_SYMBOL:  /* Ignore a place holder */
 939                 code++;
 940                 goto retry;
 941         default:
 942                 return -EILSEQ;
 943         }
 944         code++;
 945
 946         return process_fetch_insn_bottom(code, val, dest, base);
 947 }
 948 NOKPROBE_SYMBOL(process_fetch_insn)
 949
 950 /* Kprobe handler */
 951 static nokprobe_inline void
 952 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
 953                     struct trace_event_file *trace_file)
 954 {
 955         struct kprobe_trace_entry_head *entry;
 956         struct ring_buffer_event *event;
 957         struct ring_buffer *buffer;
 958         int size, dsize, pc;
 959         unsigned long irq_flags;
 960         struct trace_event_call *call = &tk->tp.call;
 961
 962         WARN_ON(call != trace_file->event_call);
 963
 964         if (trace_trigger_soft_disabled(trace_file))
 965                 return;
 966
 967         local_save_flags(irq_flags);
 968         pc = preempt_count();
 969
 970         dsize = __get_data_size(&tk->tp, regs);
 971         size = sizeof(*entry) + tk->tp.size + dsize;
 972
 973         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
 974                                                 call->event.type,
 975                                                 size, irq_flags, pc);
 976         if (!event)
 977                 return;
 978
 979         entry = ring_buffer_event_data(event);
 980         entry->ip = (unsigned long)tk->rp.kp.addr;
 981         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
 982
 983         event_trigger_unlock_commit_regs(trace_file, buffer, event,
 984                                          entry, irq_flags, pc, regs);
 985 }
 986
 987 static void
 988 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
 989 {
 990         struct event_file_link *link;
 991
 992         list_for_each_entry_rcu(link, &tk->tp.files, list)
 993                 __kprobe_trace_func(tk, regs, link->file);
 994 }
 995 NOKPROBE_SYMBOL(kprobe_trace_func);
 996
 997 /* Kretprobe handler */
 998 static nokprobe_inline void
 999 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1000                        struct pt_regs *regs,
1001                        struct trace_event_file *trace_file)
1002 {
1003         struct kretprobe_trace_entry_head *entry;
1004         struct ring_buffer_event *event;
1005         struct ring_buffer *buffer;
1006         int size, pc, dsize;
1007         unsigned long irq_flags;
1008         struct trace_event_call *call = &tk->tp.call;
1009
1010         WARN_ON(call != trace_file->event_call);
1011
1012         if (trace_trigger_soft_disabled(trace_file))
1013                 return;
1014
1015         local_save_flags(irq_flags);
1016         pc = preempt_count();
1017
1018         dsize = __get_data_size(&tk->tp, regs);
1019         size = sizeof(*entry) + tk->tp.size + dsize;
1020
1021         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1022                                                 call->event.type,
1023                                                 size, irq_flags, pc);
1024         if (!event)
1025                 return;
1026
1027         entry = ring_buffer_event_data(event);
1028         entry->func = (unsigned long)tk->rp.kp.addr;
1029         entry->ret_ip = (unsigned long)ri->ret_addr;
1030         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1031
1032         event_trigger_unlock_commit_regs(trace_file, buffer, event,
1033                                          entry, irq_flags, pc, regs);
1034 }
1035
1036 static void
1037 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1038                      struct pt_regs *regs)
1039 {
1040         struct event_file_link *link;
1041
1042         list_for_each_entry_rcu(link, &tk->tp.files, list)
1043                 __kretprobe_trace_func(tk, ri, regs, link->file);
1044 }
1045 NOKPROBE_SYMBOL(kretprobe_trace_func);
1046
1047 /* Event entry printers */
1048 static enum print_line_t
1049 print_kprobe_event(struct trace_iterator *iter, int flags,
1050                    struct trace_event *event)
1051 {
1052         struct kprobe_trace_entry_head *field;
1053         struct trace_seq *s = &iter->seq;
1054         struct trace_probe *tp;
1055
1056         field = (struct kprobe_trace_entry_head *)iter->ent;
1057         tp = container_of(event, struct trace_probe, call.event);
1058
1059         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1060
1061         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1062                 goto out;
1063
1064         trace_seq_putc(s, ')');
1065
1066         if (print_probe_args(s, tp->args, tp->nr_args,
1067                              (u8 *)&field[1], field) < 0)
1068                 goto out;
1069
1070         trace_seq_putc(s, '\n');
1071  out:
1072         return trace_handle_return(s);
1073 }
1074
1075 static enum print_line_t
1076 print_kretprobe_event(struct trace_iterator *iter, int flags,
1077                       struct trace_event *event)
1078 {
1079         struct kretprobe_trace_entry_head *field;
1080         struct trace_seq *s = &iter->seq;
1081         struct trace_probe *tp;
1082
1083         field = (struct kretprobe_trace_entry_head *)iter->ent;
1084         tp = container_of(event, struct trace_probe, call.event);
1085
1086         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1087
1088         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1089                 goto out;
1090
1091         trace_seq_puts(s, " <- ");
1092
1093         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1094                 goto out;
1095
1096         trace_seq_putc(s, ')');
1097
1098         if (print_probe_args(s, tp->args, tp->nr_args,
1099                              (u8 *)&field[1], field) < 0)
1100                 goto out;
1101
1102         trace_seq_putc(s, '\n');
1103
1104  out:
1105         return trace_handle_return(s);
1106 }
1107
1108
1109 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1110 {
1111         int ret;
1112         struct kprobe_trace_entry_head field;
1113         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1114
1115         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1116
1117         return traceprobe_define_arg_fields(event_call, sizeof(field), &tk->tp);
1118 }
1119
1120 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1121 {
1122         int ret;
1123         struct kretprobe_trace_entry_head field;
1124         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1125
1126         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1127         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1128
1129         return traceprobe_define_arg_fields(event_call, sizeof(field), &tk->tp);
1130 }
1131
1132 #ifdef CONFIG_PERF_EVENTS
1133
1134 /* Kprobe profile handler */
1135 static int
1136 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1137 {
1138         struct trace_event_call *call = &tk->tp.call;
1139         struct kprobe_trace_entry_head *entry;
1140         struct hlist_head *head;
1141         int size, __size, dsize;
1142         int rctx;
1143
1144         if (bpf_prog_array_valid(call)) {
1145                 unsigned long orig_ip = instruction_pointer(regs);
1146                 int ret;
1147
1148                 ret = trace_call_bpf(call, regs);
1149
1150                 /*
1151                  * We need to check and see if we modified the pc of the
1152                  * pt_regs, and if so return 1 so that we don't do the
1153                  * single stepping.
1154                  */
1155                 if (orig_ip != instruction_pointer(regs))
1156                         return 1;
1157                 if (!ret)
1158                         return 0;
1159         }
1160
1161         head = this_cpu_ptr(call->perf_events);
1162         if (hlist_empty(head))
1163                 return 0;
1164
1165         dsize = __get_data_size(&tk->tp, regs);
1166         __size = sizeof(*entry) + tk->tp.size + dsize;
1167         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1168         size -= sizeof(u32);
1169
1170         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1171         if (!entry)
1172                 return 0;
1173
1174         entry->ip = (unsigned long)tk->rp.kp.addr;
1175         memset(&entry[1], 0, dsize);
1176         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1177         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1178                               head, NULL);
1179         return 0;
1180 }
1181 NOKPROBE_SYMBOL(kprobe_perf_func);
1182
1183 /* Kretprobe profile handler */
1184 static void
1185 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1186                     struct pt_regs *regs)
1187 {
1188         struct trace_event_call *call = &tk->tp.call;
1189         struct kretprobe_trace_entry_head *entry;
1190         struct hlist_head *head;
1191         int size, __size, dsize;
1192         int rctx;
1193
1194         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1195                 return;
1196
1197         head = this_cpu_ptr(call->perf_events);
1198         if (hlist_empty(head))
1199                 return;
1200
1201         dsize = __get_data_size(&tk->tp, regs);
1202         __size = sizeof(*entry) + tk->tp.size + dsize;
1203         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1204         size -= sizeof(u32);
1205
1206         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1207         if (!entry)
1208                 return;
1209
1210         entry->func = (unsigned long)tk->rp.kp.addr;
1211         entry->ret_ip = (unsigned long)ri->ret_addr;
1212         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1213         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1214                               head, NULL);
1215 }
1216 NOKPROBE_SYMBOL(kretprobe_perf_func);
1217
1218 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1219                         const char **symbol, u64 *probe_offset,
1220                         u64 *probe_addr, bool perf_type_tracepoint)
1221 {
1222         const char *pevent = trace_event_name(event->tp_event);
1223         const char *group = event->tp_event->class->system;
1224         struct trace_kprobe *tk;
1225
1226         if (perf_type_tracepoint)
1227                 tk = find_trace_kprobe(pevent, group);
1228         else
1229                 tk = event->tp_event->data;
1230         if (!tk)
1231                 return -EINVAL;
1232
1233         *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1234                                               : BPF_FD_TYPE_KPROBE;
1235         if (tk->symbol) {
1236                 *symbol = tk->symbol;
1237                 *probe_offset = tk->rp.kp.offset;
1238                 *probe_addr = 0;
1239         } else {
1240                 *symbol = NULL;
1241                 *probe_offset = 0;
1242                 *probe_addr = (unsigned long)tk->rp.kp.addr;
1243         }
1244         return 0;
1245 }
1246 #endif  /* CONFIG_PERF_EVENTS */
1247
1248 /*
1249  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1250  *
1251  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1252  * lockless, but we can't race with this __init function.
1253  */
1254 static int kprobe_register(struct trace_event_call *event,
1255                            enum trace_reg type, void *data)
1256 {
1257         struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1258         struct trace_event_file *file = data;
1259
1260         switch (type) {
1261         case TRACE_REG_REGISTER:
1262                 return enable_trace_kprobe(tk, file);
1263         case TRACE_REG_UNREGISTER:
1264                 return disable_trace_kprobe(tk, file);
1265
1266 #ifdef CONFIG_PERF_EVENTS
1267         case TRACE_REG_PERF_REGISTER:
1268                 return enable_trace_kprobe(tk, NULL);
1269         case TRACE_REG_PERF_UNREGISTER:
1270                 return disable_trace_kprobe(tk, NULL);
1271         case TRACE_REG_PERF_OPEN:
1272         case TRACE_REG_PERF_CLOSE:
1273         case TRACE_REG_PERF_ADD:
1274         case TRACE_REG_PERF_DEL:
1275                 return 0;
1276 #endif
1277         }
1278         return 0;
1279 }
1280
1281 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1282 {
1283         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1284         int ret = 0;
1285
1286         raw_cpu_inc(*tk->nhit);
1287
1288         if (tk->tp.flags & TP_FLAG_TRACE)
1289                 kprobe_trace_func(tk, regs);
1290 #ifdef CONFIG_PERF_EVENTS
1291         if (tk->tp.flags & TP_FLAG_PROFILE)
1292                 ret = kprobe_perf_func(tk, regs);
1293 #endif
1294         return ret;
1295 }
1296 NOKPROBE_SYMBOL(kprobe_dispatcher);
1297
1298 static int
1299 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1300 {
1301         struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1302
1303         raw_cpu_inc(*tk->nhit);
1304
1305         if (tk->tp.flags & TP_FLAG_TRACE)
1306                 kretprobe_trace_func(tk, ri, regs);
1307 #ifdef CONFIG_PERF_EVENTS
1308         if (tk->tp.flags & TP_FLAG_PROFILE)
1309                 kretprobe_perf_func(tk, ri, regs);
1310 #endif
1311         return 0;       /* We don't tweek kernel, so just return 0 */
1312 }
1313 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1314
1315 static struct trace_event_functions kretprobe_funcs = {
1316         .trace          = print_kretprobe_event
1317 };
1318
1319 static struct trace_event_functions kprobe_funcs = {
1320         .trace          = print_kprobe_event
1321 };
1322
1323 static inline void init_trace_event_call(struct trace_kprobe *tk,
1324                                          struct trace_event_call *call)
1325 {
1326         INIT_LIST_HEAD(&call->class->fields);
1327         if (trace_kprobe_is_return(tk)) {
1328                 call->event.funcs = &kretprobe_funcs;
1329                 call->class->define_fields = kretprobe_event_define_fields;
1330         } else {
1331                 call->event.funcs = &kprobe_funcs;
1332                 call->class->define_fields = kprobe_event_define_fields;
1333         }
1334
1335         call->flags = TRACE_EVENT_FL_KPROBE;
1336         call->class->reg = kprobe_register;
1337         call->data = tk;
1338 }
1339
1340 static int register_kprobe_event(struct trace_kprobe *tk)
1341 {
1342         struct trace_event_call *call = &tk->tp.call;
1343         int ret = 0;
1344
1345         init_trace_event_call(tk, call);
1346
1347         if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1348                 return -ENOMEM;
1349         ret = register_trace_event(&call->event);
1350         if (!ret) {
1351                 kfree(call->print_fmt);
1352                 return -ENODEV;
1353         }
1354         ret = trace_add_event_call(call);
1355         if (ret) {
1356                 pr_info("Failed to register kprobe event: %s\n",
1357                         trace_event_name(call));
1358                 kfree(call->print_fmt);
1359                 unregister_trace_event(&call->event);
1360         }
1361         return ret;
1362 }
1363
1364 static int unregister_kprobe_event(struct trace_kprobe *tk)
1365 {
1366         int ret;
1367
1368         /* tp->event is unregistered in trace_remove_event_call() */
1369         ret = trace_remove_event_call(&tk->tp.call);
1370         if (!ret)
1371                 kfree(tk->tp.call.print_fmt);
1372         return ret;
1373 }
1374
1375 #ifdef CONFIG_PERF_EVENTS
1376 /* create a trace_kprobe, but don't add it to global lists */
1377 struct trace_event_call *
1378 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1379                           bool is_return)
1380 {
1381         struct trace_kprobe *tk;
1382         int ret;
1383         char *event;
1384
1385         /*
1386          * local trace_kprobes are not added to dyn_event, so they are never
1387          * searched in find_trace_kprobe(). Therefore, there is no concern of
1388          * duplicated name here.
1389          */
1390         event = func ? func : "DUMMY_EVENT";
1391
1392         tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1393                                 offs, 0 /* maxactive */, 0 /* nargs */,
1394                                 is_return);
1395
1396         if (IS_ERR(tk)) {
1397                 pr_info("Failed to allocate trace_probe.(%d)\n",
1398                         (int)PTR_ERR(tk));
1399                 return ERR_CAST(tk);
1400         }
1401
1402         init_trace_event_call(tk, &tk->tp.call);
1403
1404         if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1405                 ret = -ENOMEM;
1406                 goto error;
1407         }
1408
1409         ret = __register_trace_kprobe(tk);
1410         if (ret < 0) {
1411                 kfree(tk->tp.call.print_fmt);
1412                 goto error;
1413         }
1414
1415         return &tk->tp.call;
1416 error:
1417         free_trace_kprobe(tk);
1418         return ERR_PTR(ret);
1419 }
1420
1421 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1422 {
1423         struct trace_kprobe *tk;
1424
1425         tk = container_of(event_call, struct trace_kprobe, tp.call);
1426
1427         if (trace_probe_is_enabled(&tk->tp)) {
1428                 WARN_ON(1);
1429                 return;
1430         }
1431
1432         __unregister_trace_kprobe(tk);
1433
1434         kfree(tk->tp.call.print_fmt);
1435         free_trace_kprobe(tk);
1436 }
1437 #endif /* CONFIG_PERF_EVENTS */
1438
1439 /* Make a tracefs interface for controlling probe points */
1440 static __init int init_kprobe_trace(void)
1441 {
1442         struct dentry *d_tracer;
1443         struct dentry *entry;
1444         int ret;
1445
1446         ret = dyn_event_register(&trace_kprobe_ops);
1447         if (ret)
1448                 return ret;
1449
1450         if (register_module_notifier(&trace_kprobe_module_nb))
1451                 return -EINVAL;
1452
1453         d_tracer = tracing_init_dentry();
1454         if (IS_ERR(d_tracer))
1455                 return 0;
1456
1457         entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1458                                     NULL, &kprobe_events_ops);
1459
1460         /* Event list interface */
1461         if (!entry)
1462                 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1463
1464         /* Profile interface */
1465         entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1466                                     NULL, &kprobe_profile_ops);
1467
1468         if (!entry)
1469                 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1470         return 0;
1471 }
1472 fs_initcall(init_kprobe_trace);
1473
1474
1475 #ifdef CONFIG_FTRACE_STARTUP_TEST
1476 static __init struct trace_event_file *
1477 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1478 {
1479         struct trace_event_file *file;
1480
1481         list_for_each_entry(file, &tr->events, list)
1482                 if (file->event_call == &tk->tp.call)
1483                         return file;
1484
1485         return NULL;
1486 }
1487
1488 /*
1489  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1490  * stage, we can do this lockless.
1491  */
1492 static __init int kprobe_trace_self_tests_init(void)
1493 {
1494         int ret, warn = 0;
1495         int (*target)(int, int, int, int, int, int);
1496         struct trace_kprobe *tk;
1497         struct trace_event_file *file;
1498
1499         if (tracing_is_disabled())
1500                 return -ENODEV;
1501
1502         target = kprobe_trace_selftest_target;
1503
1504         pr_info("Testing kprobe tracing: ");
1505
1506         ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)",
1507                                 create_or_delete_trace_kprobe);
1508         if (WARN_ON_ONCE(ret)) {
1509                 pr_warn("error on probing function entry.\n");
1510                 warn++;
1511         } else {
1512                 /* Enable trace point */
1513                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1514                 if (WARN_ON_ONCE(tk == NULL)) {
1515                         pr_warn("error on getting new probe.\n");
1516                         warn++;
1517                 } else {
1518                         file = find_trace_probe_file(tk, top_trace_array());
1519                         if (WARN_ON_ONCE(file == NULL)) {
1520                                 pr_warn("error on getting probe file.\n");
1521                                 warn++;
1522                         } else
1523                                 enable_trace_kprobe(tk, file);
1524                 }
1525         }
1526
1527         ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval",
1528                                 create_or_delete_trace_kprobe);
1529         if (WARN_ON_ONCE(ret)) {
1530                 pr_warn("error on probing function return.\n");
1531                 warn++;
1532         } else {
1533                 /* Enable trace point */
1534                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1535                 if (WARN_ON_ONCE(tk == NULL)) {
1536                         pr_warn("error on getting 2nd new probe.\n");
1537                         warn++;
1538                 } else {
1539                         file = find_trace_probe_file(tk, top_trace_array());
1540                         if (WARN_ON_ONCE(file == NULL)) {
1541                                 pr_warn("error on getting probe file.\n");
1542                                 warn++;
1543                         } else
1544                                 enable_trace_kprobe(tk, file);
1545                 }
1546         }
1547
1548         if (warn)
1549                 goto end;
1550
1551         ret = target(1, 2, 3, 4, 5, 6);
1552
1553         /*
1554          * Not expecting an error here, the check is only to prevent the
1555          * optimizer from removing the call to target() as otherwise there
1556          * are no side-effects and the call is never performed.
1557          */
1558         if (ret != 21)
1559                 warn++;
1560
1561         /* Disable trace points before removing it */
1562         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1563         if (WARN_ON_ONCE(tk == NULL)) {
1564                 pr_warn("error on getting test probe.\n");
1565                 warn++;
1566         } else {
1567                 if (trace_kprobe_nhit(tk) != 1) {
1568                         pr_warn("incorrect number of testprobe hits\n");
1569                         warn++;
1570                 }
1571
1572                 file = find_trace_probe_file(tk, top_trace_array());
1573                 if (WARN_ON_ONCE(file == NULL)) {
1574                         pr_warn("error on getting probe file.\n");
1575                         warn++;
1576                 } else
1577                         disable_trace_kprobe(tk, file);
1578         }
1579
1580         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1581         if (WARN_ON_ONCE(tk == NULL)) {
1582                 pr_warn("error on getting 2nd test probe.\n");
1583                 warn++;
1584         } else {
1585                 if (trace_kprobe_nhit(tk) != 1) {
1586                         pr_warn("incorrect number of testprobe2 hits\n");
1587                         warn++;
1588                 }
1589
1590                 file = find_trace_probe_file(tk, top_trace_array());
1591                 if (WARN_ON_ONCE(file == NULL)) {
1592                         pr_warn("error on getting probe file.\n");
1593                         warn++;
1594                 } else
1595                         disable_trace_kprobe(tk, file);
1596         }
1597
1598         ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe);
1599         if (WARN_ON_ONCE(ret)) {
1600                 pr_warn("error on deleting a probe.\n");
1601                 warn++;
1602         }
1603
1604         ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe);
1605         if (WARN_ON_ONCE(ret)) {
1606                 pr_warn("error on deleting a probe.\n");
1607                 warn++;
1608         }
1609
1610 end:
1611         ret = dyn_events_release_all(&trace_kprobe_ops);
1612         if (WARN_ON_ONCE(ret)) {
1613                 pr_warn("error on cleaning up probes.\n");
1614                 warn++;
1615         }
1616         /*
1617          * Wait for the optimizer work to finish. Otherwise it might fiddle
1618          * with probes in already freed __init text.
1619          */
1620         wait_for_kprobe_optimizer();
1621         if (warn)
1622                 pr_cont("NG: Some tests are failed. Please check them.\n");
1623         else
1624                 pr_cont("OK\n");
1625         return 0;
1626 }
1627
1628 late_initcall(kprobe_trace_self_tests_init);
1629
1630 #endif