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/security.h>
  11 #include <linux/module.h>
  12 #include <linux/uaccess.h>
  13 #include <linux/rculist.h>
  14 #include <linux/error-injection.h>
  15
  16 #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
  17
  18 #include "trace_dynevent.h"
  19 #include "trace_kprobe_selftest.h"
  20 #include "trace_probe.h"
  21 #include "trace_probe_tmpl.h"
  22
  23 #define KPROBE_EVENT_SYSTEM "kprobes"
  24 #define KRETPROBE_MAXACTIVE_MAX 4096
  25
  26 /* Kprobe early definition from command line */
  27 static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
  28
  29 static int __init set_kprobe_boot_events(char *str)
  30 {
  31         strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
  32         disable_tracing_selftest("running kprobe events");
  33
  34         return 0;
  35 }
  36 __setup("kprobe_event=", set_kprobe_boot_events);
  37
  38 static int trace_kprobe_create(const char *raw_command);
  39 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
  40 static int trace_kprobe_release(struct dyn_event *ev);
  41 static bool trace_kprobe_is_busy(struct dyn_event *ev);
  42 static bool trace_kprobe_match(const char *system, const char *event,
  43                         int argc, const char **argv, struct dyn_event *ev);
  44
  45 static struct dyn_event_operations trace_kprobe_ops = {
  46         .create = trace_kprobe_create,
  47         .show = trace_kprobe_show,
  48         .is_busy = trace_kprobe_is_busy,
  49         .free = trace_kprobe_release,
  50         .match = trace_kprobe_match,
  51 };
  52
  53 /*
  54  * Kprobe event core functions
  55  */
  56 struct trace_kprobe {
  57         struct dyn_event        devent;
  58         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
  59         unsigned long __percpu *nhit;
  60         const char              *symbol;        /* symbol name */
  61         struct trace_probe      tp;
  62 };
  63
  64 static bool is_trace_kprobe(struct dyn_event *ev)
  65 {
  66         return ev->ops == &trace_kprobe_ops;
  67 }
  68
  69 static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
  70 {
  71         return container_of(ev, struct trace_kprobe, devent);
  72 }
  73
  74 /**
  75  * for_each_trace_kprobe - iterate over the trace_kprobe list
  76  * @pos:        the struct trace_kprobe * for each entry
  77  * @dpos:       the struct dyn_event * to use as a loop cursor
  78  */
  79 #define for_each_trace_kprobe(pos, dpos)        \
  80         for_each_dyn_event(dpos)                \
  81                 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
  82
  83 #define SIZEOF_TRACE_KPROBE(n)                          \
  84         (offsetof(struct trace_kprobe, tp.args) +       \
  85         (sizeof(struct probe_arg) * (n)))
  86
  87 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
  88 {
  89         return tk->rp.handler != NULL;
  90 }
  91
  92 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
  93 {
  94         return tk->symbol ? tk->symbol : "unknown";
  95 }
  96
  97 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
  98 {
  99         return tk->rp.kp.offset;
 100 }
 101
 102 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
 103 {
 104         return !!(kprobe_gone(&tk->rp.kp));
 105 }
 106
 107 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
 108                                                  struct module *mod)
 109 {
 110         int len = strlen(module_name(mod));
 111         const char *name = trace_kprobe_symbol(tk);
 112
 113         return strncmp(module_name(mod), name, len) == 0 && name[len] == ':';
 114 }
 115
 116 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
 117 {
 118         char *p;
 119         bool ret;
 120
 121         if (!tk->symbol)
 122                 return false;
 123         p = strchr(tk->symbol, ':');
 124         if (!p)
 125                 return true;
 126         *p = '\0';
 127         rcu_read_lock_sched();
 128         ret = !!find_module(tk->symbol);
 129         rcu_read_unlock_sched();
 130         *p = ':';
 131
 132         return ret;
 133 }
 134
 135 static bool trace_kprobe_is_busy(struct dyn_event *ev)
 136 {
 137         struct trace_kprobe *tk = to_trace_kprobe(ev);
 138
 139         return trace_probe_is_enabled(&tk->tp);
 140 }
 141
 142 static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
 143                                             int argc, const char **argv)
 144 {
 145         char buf[MAX_ARGSTR_LEN + 1];
 146
 147         if (!argc)
 148                 return true;
 149
 150         if (!tk->symbol)
 151                 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
 152         else if (tk->rp.kp.offset)
 153                 snprintf(buf, sizeof(buf), "%s+%u",
 154                          trace_kprobe_symbol(tk), tk->rp.kp.offset);
 155         else
 156                 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
 157         if (strcmp(buf, argv[0]))
 158                 return false;
 159         argc--; argv++;
 160
 161         return trace_probe_match_command_args(&tk->tp, argc, argv);
 162 }
 163
 164 static bool trace_kprobe_match(const char *system, const char *event,
 165                         int argc, const char **argv, struct dyn_event *ev)
 166 {
 167         struct trace_kprobe *tk = to_trace_kprobe(ev);
 168
 169         return strcmp(trace_probe_name(&tk->tp), event) == 0 &&
 170             (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
 171             trace_kprobe_match_command_head(tk, argc, argv);
 172 }
 173
 174 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
 175 {
 176         unsigned long nhit = 0;
 177         int cpu;
 178
 179         for_each_possible_cpu(cpu)
 180                 nhit += *per_cpu_ptr(tk->nhit, cpu);
 181
 182         return nhit;
 183 }
 184
 185 static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk)
 186 {
 187         return !(list_empty(&tk->rp.kp.list) &&
 188                  hlist_unhashed(&tk->rp.kp.hlist));
 189 }
 190
 191 /* Return 0 if it fails to find the symbol address */
 192 static nokprobe_inline
 193 unsigned long trace_kprobe_address(struct trace_kprobe *tk)
 194 {
 195         unsigned long addr;
 196
 197         if (tk->symbol) {
 198                 addr = (unsigned long)
 199                         kallsyms_lookup_name(trace_kprobe_symbol(tk));
 200                 if (addr)
 201                         addr += tk->rp.kp.offset;
 202         } else {
 203                 addr = (unsigned long)tk->rp.kp.addr;
 204         }
 205         return addr;
 206 }
 207
 208 static nokprobe_inline struct trace_kprobe *
 209 trace_kprobe_primary_from_call(struct trace_event_call *call)
 210 {
 211         struct trace_probe *tp;
 212
 213         tp = trace_probe_primary_from_call(call);
 214         if (WARN_ON_ONCE(!tp))
 215                 return NULL;
 216
 217         return container_of(tp, struct trace_kprobe, tp);
 218 }
 219
 220 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
 221 {
 222         struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
 223
 224         return tk ? (kprobe_on_func_entry(tk->rp.kp.addr,
 225                         tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
 226                         tk->rp.kp.addr ? 0 : tk->rp.kp.offset) == 0) : false;
 227 }
 228
 229 bool trace_kprobe_error_injectable(struct trace_event_call *call)
 230 {
 231         struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
 232
 233         return tk ? within_error_injection_list(trace_kprobe_address(tk)) :
 234                false;
 235 }
 236
 237 static int register_kprobe_event(struct trace_kprobe *tk);
 238 static int unregister_kprobe_event(struct trace_kprobe *tk);
 239
 240 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 241 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 242                                 struct pt_regs *regs);
 243
 244 static void free_trace_kprobe(struct trace_kprobe *tk)
 245 {
 246         if (tk) {
 247                 trace_probe_cleanup(&tk->tp);
 248                 kfree(tk->symbol);
 249                 free_percpu(tk->nhit);
 250                 kfree(tk);
 251         }
 252 }
 253
 254 /*
 255  * Allocate new trace_probe and initialize it (including kprobes).
 256  */
 257 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
 258                                              const char *event,
 259                                              void *addr,
 260                                              const char *symbol,
 261                                              unsigned long offs,
 262                                              int maxactive,
 263                                              int nargs, bool is_return)
 264 {
 265         struct trace_kprobe *tk;
 266         int ret = -ENOMEM;
 267
 268         tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
 269         if (!tk)
 270                 return ERR_PTR(ret);
 271
 272         tk->nhit = alloc_percpu(unsigned long);
 273         if (!tk->nhit)
 274                 goto error;
 275
 276         if (symbol) {
 277                 tk->symbol = kstrdup(symbol, GFP_KERNEL);
 278                 if (!tk->symbol)
 279                         goto error;
 280                 tk->rp.kp.symbol_name = tk->symbol;
 281                 tk->rp.kp.offset = offs;
 282         } else
 283                 tk->rp.kp.addr = addr;
 284
 285         if (is_return)
 286                 tk->rp.handler = kretprobe_dispatcher;
 287         else
 288                 tk->rp.kp.pre_handler = kprobe_dispatcher;
 289
 290         tk->rp.maxactive = maxactive;
 291         INIT_HLIST_NODE(&tk->rp.kp.hlist);
 292         INIT_LIST_HEAD(&tk->rp.kp.list);
 293
 294         ret = trace_probe_init(&tk->tp, event, group, false);
 295         if (ret < 0)
 296                 goto error;
 297
 298         dyn_event_init(&tk->devent, &trace_kprobe_ops);
 299         return tk;
 300 error:
 301         free_trace_kprobe(tk);
 302         return ERR_PTR(ret);
 303 }
 304
 305 static struct trace_kprobe *find_trace_kprobe(const char *event,
 306                                               const char *group)
 307 {
 308         struct dyn_event *pos;
 309         struct trace_kprobe *tk;
 310
 311         for_each_trace_kprobe(tk, pos)
 312                 if (strcmp(trace_probe_name(&tk->tp), event) == 0 &&
 313                     strcmp(trace_probe_group_name(&tk->tp), group) == 0)
 314                         return tk;
 315         return NULL;
 316 }
 317
 318 static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
 319 {
 320         int ret = 0;
 321
 322         if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) {
 323                 if (trace_kprobe_is_return(tk))
 324                         ret = enable_kretprobe(&tk->rp);
 325                 else
 326                         ret = enable_kprobe(&tk->rp.kp);
 327         }
 328
 329         return ret;
 330 }
 331
 332 static void __disable_trace_kprobe(struct trace_probe *tp)
 333 {
 334         struct trace_probe *pos;
 335         struct trace_kprobe *tk;
 336
 337         list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
 338                 tk = container_of(pos, struct trace_kprobe, tp);
 339                 if (!trace_kprobe_is_registered(tk))
 340                         continue;
 341                 if (trace_kprobe_is_return(tk))
 342                         disable_kretprobe(&tk->rp);
 343                 else
 344                         disable_kprobe(&tk->rp.kp);
 345         }
 346 }
 347
 348 /*
 349  * Enable trace_probe
 350  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
 351  */
 352 static int enable_trace_kprobe(struct trace_event_call *call,
 353                                 struct trace_event_file *file)
 354 {
 355         struct trace_probe *pos, *tp;
 356         struct trace_kprobe *tk;
 357         bool enabled;
 358         int ret = 0;
 359
 360         tp = trace_probe_primary_from_call(call);
 361         if (WARN_ON_ONCE(!tp))
 362                 return -ENODEV;
 363         enabled = trace_probe_is_enabled(tp);
 364
 365         /* This also changes "enabled" state */
 366         if (file) {
 367                 ret = trace_probe_add_file(tp, file);
 368                 if (ret)
 369                         return ret;
 370         } else
 371                 trace_probe_set_flag(tp, TP_FLAG_PROFILE);
 372
 373         if (enabled)
 374                 return 0;
 375
 376         list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
 377                 tk = container_of(pos, struct trace_kprobe, tp);
 378                 if (trace_kprobe_has_gone(tk))
 379                         continue;
 380                 ret = __enable_trace_kprobe(tk);
 381                 if (ret)
 382                         break;
 383                 enabled = true;
 384         }
 385
 386         if (ret) {
 387                 /* Failed to enable one of them. Roll back all */
 388                 if (enabled)
 389                         __disable_trace_kprobe(tp);
 390                 if (file)
 391                         trace_probe_remove_file(tp, file);
 392                 else
 393                         trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
 394         }
 395
 396         return ret;
 397 }
 398
 399 /*
 400  * Disable trace_probe
 401  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
 402  */
 403 static int disable_trace_kprobe(struct trace_event_call *call,
 404                                 struct trace_event_file *file)
 405 {
 406         struct trace_probe *tp;
 407
 408         tp = trace_probe_primary_from_call(call);
 409         if (WARN_ON_ONCE(!tp))
 410                 return -ENODEV;
 411
 412         if (file) {
 413                 if (!trace_probe_get_file_link(tp, file))
 414                         return -ENOENT;
 415                 if (!trace_probe_has_single_file(tp))
 416                         goto out;
 417                 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
 418         } else
 419                 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
 420
 421         if (!trace_probe_is_enabled(tp))
 422                 __disable_trace_kprobe(tp);
 423
 424  out:
 425         if (file)
 426                 /*
 427                  * Synchronization is done in below function. For perf event,
 428                  * file == NULL and perf_trace_event_unreg() calls
 429                  * tracepoint_synchronize_unregister() to ensure synchronize
 430                  * event. We don't need to care about it.
 431                  */
 432                 trace_probe_remove_file(tp, file);
 433
 434         return 0;
 435 }
 436
 437 #if defined(CONFIG_DYNAMIC_FTRACE) && \
 438         !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
 439 static bool __within_notrace_func(unsigned long addr)
 440 {
 441         unsigned long offset, size;
 442
 443         if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
 444                 return false;
 445
 446         /* Get the entry address of the target function */
 447         addr -= offset;
 448
 449         /*
 450          * Since ftrace_location_range() does inclusive range check, we need
 451          * to subtract 1 byte from the end address.
 452          */
 453         return !ftrace_location_range(addr, addr + size - 1);
 454 }
 455
 456 static bool within_notrace_func(struct trace_kprobe *tk)
 457 {
 458         unsigned long addr = trace_kprobe_address(tk);
 459         char symname[KSYM_NAME_LEN], *p;
 460
 461         if (!__within_notrace_func(addr))
 462                 return false;
 463
 464         /* Check if the address is on a suffixed-symbol */
 465         if (!lookup_symbol_name(addr, symname)) {
 466                 p = strchr(symname, '.');
 467                 if (!p)
 468                         return true;
 469                 *p = '\0';
 470                 addr = (unsigned long)kprobe_lookup_name(symname, 0);
 471                 if (addr)
 472                         return __within_notrace_func(addr);
 473         }
 474
 475         return true;
 476 }
 477 #else
 478 #define within_notrace_func(tk) (false)
 479 #endif
 480
 481 /* Internal register function - just handle k*probes and flags */
 482 static int __register_trace_kprobe(struct trace_kprobe *tk)
 483 {
 484         int i, ret;
 485
 486         ret = security_locked_down(LOCKDOWN_KPROBES);
 487         if (ret)
 488                 return ret;
 489
 490         if (trace_kprobe_is_registered(tk))
 491                 return -EINVAL;
 492
 493         if (within_notrace_func(tk)) {
 494                 pr_warn("Could not probe notrace function %s\n",
 495                         trace_kprobe_symbol(tk));
 496                 return -EINVAL;
 497         }
 498
 499         for (i = 0; i < tk->tp.nr_args; i++) {
 500                 ret = traceprobe_update_arg(&tk->tp.args[i]);
 501                 if (ret)
 502                         return ret;
 503         }
 504
 505         /* Set/clear disabled flag according to tp->flag */
 506         if (trace_probe_is_enabled(&tk->tp))
 507                 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
 508         else
 509                 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 510
 511         if (trace_kprobe_is_return(tk))
 512                 ret = register_kretprobe(&tk->rp);
 513         else
 514                 ret = register_kprobe(&tk->rp.kp);
 515
 516         return ret;
 517 }
 518
 519 /* Internal unregister function - just handle k*probes and flags */
 520 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 521 {
 522         if (trace_kprobe_is_registered(tk)) {
 523                 if (trace_kprobe_is_return(tk))
 524                         unregister_kretprobe(&tk->rp);
 525                 else
 526                         unregister_kprobe(&tk->rp.kp);
 527                 /* Cleanup kprobe for reuse and mark it unregistered */
 528                 INIT_HLIST_NODE(&tk->rp.kp.hlist);
 529                 INIT_LIST_HEAD(&tk->rp.kp.list);
 530                 if (tk->rp.kp.symbol_name)
 531                         tk->rp.kp.addr = NULL;
 532         }
 533 }
 534
 535 /* Unregister a trace_probe and probe_event */
 536 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 537 {
 538         /* If other probes are on the event, just unregister kprobe */
 539         if (trace_probe_has_sibling(&tk->tp))
 540                 goto unreg;
 541
 542         /* Enabled event can not be unregistered */
 543         if (trace_probe_is_enabled(&tk->tp))
 544                 return -EBUSY;
 545
 546         /* If there's a reference to the dynamic event */
 547         if (trace_event_dyn_busy(trace_probe_event_call(&tk->tp)))
 548                 return -EBUSY;
 549
 550         /* Will fail if probe is being used by ftrace or perf */
 551         if (unregister_kprobe_event(tk))
 552                 return -EBUSY;
 553
 554 unreg:
 555         __unregister_trace_kprobe(tk);
 556         dyn_event_remove(&tk->devent);
 557         trace_probe_unlink(&tk->tp);
 558
 559         return 0;
 560 }
 561
 562 static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
 563                                          struct trace_kprobe *comp)
 564 {
 565         struct trace_probe_event *tpe = orig->tp.event;
 566         struct trace_probe *pos;
 567         int i;
 568
 569         list_for_each_entry(pos, &tpe->probes, list) {
 570                 orig = container_of(pos, struct trace_kprobe, tp);
 571                 if (strcmp(trace_kprobe_symbol(orig),
 572                            trace_kprobe_symbol(comp)) ||
 573                     trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
 574                         continue;
 575
 576                 /*
 577                  * trace_probe_compare_arg_type() ensured that nr_args and
 578                  * each argument name and type are same. Let's compare comm.
 579                  */
 580                 for (i = 0; i < orig->tp.nr_args; i++) {
 581                         if (strcmp(orig->tp.args[i].comm,
 582                                    comp->tp.args[i].comm))
 583                                 break;
 584                 }
 585
 586                 if (i == orig->tp.nr_args)
 587                         return true;
 588         }
 589
 590         return false;
 591 }
 592
 593 static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
 594 {
 595         int ret;
 596
 597         ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
 598         if (ret) {
 599                 /* Note that argument starts index = 2 */
 600                 trace_probe_log_set_index(ret + 1);
 601                 trace_probe_log_err(0, DIFF_ARG_TYPE);
 602                 return -EEXIST;
 603         }
 604         if (trace_kprobe_has_same_kprobe(to, tk)) {
 605                 trace_probe_log_set_index(0);
 606                 trace_probe_log_err(0, SAME_PROBE);
 607                 return -EEXIST;
 608         }
 609
 610         /* Append to existing event */
 611         ret = trace_probe_append(&tk->tp, &to->tp);
 612         if (ret)
 613                 return ret;
 614
 615         /* Register k*probe */
 616         ret = __register_trace_kprobe(tk);
 617         if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
 618                 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 619                 ret = 0;
 620         }
 621
 622         if (ret)
 623                 trace_probe_unlink(&tk->tp);
 624         else
 625                 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp));
 626
 627         return ret;
 628 }
 629
 630 /* Register a trace_probe and probe_event */
 631 static int register_trace_kprobe(struct trace_kprobe *tk)
 632 {
 633         struct trace_kprobe *old_tk;
 634         int ret;
 635
 636         mutex_lock(&event_mutex);
 637
 638         old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
 639                                    trace_probe_group_name(&tk->tp));
 640         if (old_tk) {
 641                 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
 642                         trace_probe_log_set_index(0);
 643                         trace_probe_log_err(0, DIFF_PROBE_TYPE);
 644                         ret = -EEXIST;
 645                 } else {
 646                         ret = append_trace_kprobe(tk, old_tk);
 647                 }
 648                 goto end;
 649         }
 650
 651         /* Register new event */
 652         ret = register_kprobe_event(tk);
 653         if (ret) {
 654                 pr_warn("Failed to register probe event(%d)\n", ret);
 655                 goto end;
 656         }
 657
 658         /* Register k*probe */
 659         ret = __register_trace_kprobe(tk);
 660         if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
 661                 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 662                 ret = 0;
 663         }
 664
 665         if (ret < 0)
 666                 unregister_kprobe_event(tk);
 667         else
 668                 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp));
 669
 670 end:
 671         mutex_unlock(&event_mutex);
 672         return ret;
 673 }
 674
 675 /* Module notifier call back, checking event on the module */
 676 static int trace_kprobe_module_callback(struct notifier_block *nb,
 677                                        unsigned long val, void *data)
 678 {
 679         struct module *mod = data;
 680         struct dyn_event *pos;
 681         struct trace_kprobe *tk;
 682         int ret;
 683
 684         if (val != MODULE_STATE_COMING)
 685                 return NOTIFY_DONE;
 686
 687         /* Update probes on coming module */
 688         mutex_lock(&event_mutex);
 689         for_each_trace_kprobe(tk, pos) {
 690                 if (trace_kprobe_within_module(tk, mod)) {
 691                         /* Don't need to check busy - this should have gone. */
 692                         __unregister_trace_kprobe(tk);
 693                         ret = __register_trace_kprobe(tk);
 694                         if (ret)
 695                                 pr_warn("Failed to re-register probe %s on %s: %d\n",
 696                                         trace_probe_name(&tk->tp),
 697                                         module_name(mod), ret);
 698                 }
 699         }
 700         mutex_unlock(&event_mutex);
 701
 702         return NOTIFY_DONE;
 703 }
 704
 705 static struct notifier_block trace_kprobe_module_nb = {
 706         .notifier_call = trace_kprobe_module_callback,
 707         .priority = 1   /* Invoked after kprobe module callback */
 708 };
 709
 710 /* Convert certain expected symbols into '_' when generating event names */
 711 static inline void sanitize_event_name(char *name)
 712 {
 713         while (*name++ != '\0')
 714                 if (*name == ':' || *name == '.')
 715                         *name = '_';
 716 }
 717
 718 static int __trace_kprobe_create(int argc, const char *argv[])
 719 {
 720         /*
 721          * Argument syntax:
 722          *  - Add kprobe:
 723          *      p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 724          *  - Add kretprobe:
 725          *      r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
 726          *    Or
 727          *      p:[GRP/]EVENT] [MOD:]KSYM[+0]%return [FETCHARGS]
 728          *
 729          * Fetch args:
 730          *  $retval     : fetch return value
 731          *  $stack      : fetch stack address
 732          *  $stackN     : fetch Nth of stack (N:0-)
 733          *  $comm       : fetch current task comm
 734          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 735          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 736          *  %REG        : fetch register REG
 737          * Dereferencing memory fetch:
 738          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 739          * Alias name of args:
 740          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 741          * Type of args:
 742          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 743          */
 744         struct trace_kprobe *tk = NULL;
 745         int i, len, ret = 0;
 746         bool is_return = false;
 747         char *symbol = NULL, *tmp = NULL;
 748         const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
 749         int maxactive = 0;
 750         long offset = 0;
 751         void *addr = NULL;
 752         char buf[MAX_EVENT_NAME_LEN];
 753         unsigned int flags = TPARG_FL_KERNEL;
 754
 755         switch (argv[0][0]) {
 756         case 'r':
 757                 is_return = true;
 758                 break;
 759         case 'p':
 760                 break;
 761         default:
 762                 return -ECANCELED;
 763         }
 764         if (argc < 2)
 765                 return -ECANCELED;
 766
 767         trace_probe_log_init("trace_kprobe", argc, argv);
 768
 769         event = strchr(&argv[0][1], ':');
 770         if (event)
 771                 event++;
 772
 773         if (isdigit(argv[0][1])) {
 774                 if (!is_return) {
 775                         trace_probe_log_err(1, MAXACT_NO_KPROBE);
 776                         goto parse_error;
 777                 }
 778                 if (event)
 779                         len = event - &argv[0][1] - 1;
 780                 else
 781                         len = strlen(&argv[0][1]);
 782                 if (len > MAX_EVENT_NAME_LEN - 1) {
 783                         trace_probe_log_err(1, BAD_MAXACT);
 784                         goto parse_error;
 785                 }
 786                 memcpy(buf, &argv[0][1], len);
 787                 buf[len] = '\0';
 788                 ret = kstrtouint(buf, 0, &maxactive);
 789                 if (ret || !maxactive) {
 790                         trace_probe_log_err(1, BAD_MAXACT);
 791                         goto parse_error;
 792                 }
 793                 /* kretprobes instances are iterated over via a list. The
 794                  * maximum should stay reasonable.
 795                  */
 796                 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
 797                         trace_probe_log_err(1, MAXACT_TOO_BIG);
 798                         goto parse_error;
 799                 }
 800         }
 801
 802         /* try to parse an address. if that fails, try to read the
 803          * input as a symbol. */
 804         if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
 805                 trace_probe_log_set_index(1);
 806                 /* Check whether uprobe event specified */
 807                 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
 808                         ret = -ECANCELED;
 809                         goto error;
 810                 }
 811                 /* a symbol specified */
 812                 symbol = kstrdup(argv[1], GFP_KERNEL);
 813                 if (!symbol)
 814                         return -ENOMEM;
 815
 816                 tmp = strchr(symbol, '%');
 817                 if (tmp) {
 818                         if (!strcmp(tmp, "%return")) {
 819                                 *tmp = '\0';
 820                                 is_return = true;
 821                         } else {
 822                                 trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
 823                                 goto parse_error;
 824                         }
 825                 }
 826
 827                 /* TODO: support .init module functions */
 828                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 829                 if (ret || offset < 0 || offset > UINT_MAX) {
 830                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 831                         goto parse_error;
 832                 }
 833                 if (is_return)
 834                         flags |= TPARG_FL_RETURN;
 835                 ret = kprobe_on_func_entry(NULL, symbol, offset);
 836                 if (ret == 0)
 837                         flags |= TPARG_FL_FENTRY;
 838                 /* Defer the ENOENT case until register kprobe */
 839                 if (ret == -EINVAL && is_return) {
 840                         trace_probe_log_err(0, BAD_RETPROBE);
 841                         goto parse_error;
 842                 }
 843         }
 844
 845         trace_probe_log_set_index(0);
 846         if (event) {
 847                 ret = traceprobe_parse_event_name(&event, &group, buf,
 848                                                   event - argv[0]);
 849                 if (ret)
 850                         goto parse_error;
 851         } else {
 852                 /* Make a new event name */
 853                 if (symbol)
 854                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 855                                  is_return ? 'r' : 'p', symbol, offset);
 856                 else
 857                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 858                                  is_return ? 'r' : 'p', addr);
 859                 sanitize_event_name(buf);
 860                 event = buf;
 861         }
 862
 863         /* setup a probe */
 864         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
 865                                argc - 2, is_return);
 866         if (IS_ERR(tk)) {
 867                 ret = PTR_ERR(tk);
 868                 /* This must return -ENOMEM, else there is a bug */
 869                 WARN_ON_ONCE(ret != -ENOMEM);
 870                 goto out;       /* We know tk is not allocated */
 871         }
 872         argc -= 2; argv += 2;
 873
 874         /* parse arguments */
 875         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 876                 tmp = kstrdup(argv[i], GFP_KERNEL);
 877                 if (!tmp) {
 878                         ret = -ENOMEM;
 879                         goto error;
 880                 }
 881
 882                 trace_probe_log_set_index(i + 2);
 883                 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
 884                 kfree(tmp);
 885                 if (ret)
 886                         goto error;     /* This can be -ENOMEM */
 887         }
 888
 889         ret = traceprobe_set_print_fmt(&tk->tp, is_return);
 890         if (ret < 0)
 891                 goto error;
 892
 893         ret = register_trace_kprobe(tk);
 894         if (ret) {
 895                 trace_probe_log_set_index(1);
 896                 if (ret == -EILSEQ)
 897                         trace_probe_log_err(0, BAD_INSN_BNDRY);
 898                 else if (ret == -ENOENT)
 899                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 900                 else if (ret != -ENOMEM && ret != -EEXIST)
 901                         trace_probe_log_err(0, FAIL_REG_PROBE);
 902                 goto error;
 903         }
 904
 905 out:
 906         trace_probe_log_clear();
 907         kfree(symbol);
 908         return ret;
 909
 910 parse_error:
 911         ret = -EINVAL;
 912 error:
 913         free_trace_kprobe(tk);
 914         goto out;
 915 }
 916
 917 static int trace_kprobe_create(const char *raw_command)
 918 {
 919         return trace_probe_create(raw_command, __trace_kprobe_create);
 920 }
 921
 922 static int create_or_delete_trace_kprobe(const char *raw_command)
 923 {
 924         int ret;
 925
 926         if (raw_command[0] == '-')
 927                 return dyn_event_release(raw_command, &trace_kprobe_ops);
 928
 929         ret = trace_kprobe_create(raw_command);
 930         return ret == -ECANCELED ? -EINVAL : ret;
 931 }
 932
 933 static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
 934 {
 935         return create_or_delete_trace_kprobe(cmd->seq.buffer);
 936 }
 937
 938 /**
 939  * kprobe_event_cmd_init - Initialize a kprobe event command object
 940  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 941  * @buf: A pointer to the buffer used to build the command
 942  * @maxlen: The length of the buffer passed in @buf
 943  *
 944  * Initialize a synthetic event command object.  Use this before
 945  * calling any of the other kprobe_event functions.
 946  */
 947 void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
 948 {
 949         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
 950                           trace_kprobe_run_command);
 951 }
 952 EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
 953
 954 /**
 955  * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
 956  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 957  * @name: The name of the kprobe event
 958  * @loc: The location of the kprobe event
 959  * @kretprobe: Is this a return probe?
 960  * @args: Variable number of arg (pairs), one pair for each field
 961  *
 962  * NOTE: Users normally won't want to call this function directly, but
 963  * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
 964  * adds a NULL to the end of the arg list.  If this function is used
 965  * directly, make sure the last arg in the variable arg list is NULL.
 966  *
 967  * Generate a kprobe event command to be executed by
 968  * kprobe_event_gen_cmd_end().  This function can be used to generate the
 969  * complete command or only the first part of it; in the latter case,
 970  * kprobe_event_add_fields() can be used to add more fields following this.
 971  *
 972  * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
 973  * returns -EINVAL if @loc == NULL.
 974  *
 975  * Return: 0 if successful, error otherwise.
 976  */
 977 int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
 978                                  const char *name, const char *loc, ...)
 979 {
 980         char buf[MAX_EVENT_NAME_LEN];
 981         struct dynevent_arg arg;
 982         va_list args;
 983         int ret;
 984
 985         if (cmd->type != DYNEVENT_TYPE_KPROBE)
 986                 return -EINVAL;
 987
 988         if (!loc)
 989                 return -EINVAL;
 990
 991         if (kretprobe)
 992                 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
 993         else
 994                 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
 995
 996         ret = dynevent_str_add(cmd, buf);
 997         if (ret)
 998                 return ret;
 999
1000         dynevent_arg_init(&arg, 0);
1001         arg.str = loc;
1002         ret = dynevent_arg_add(cmd, &arg, NULL);
1003         if (ret)
1004                 return ret;
1005
1006         va_start(args, loc);
1007         for (;;) {
1008                 const char *field;
1009
1010                 field = va_arg(args, const char *);
1011                 if (!field)
1012                         break;
1013
1014                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1015                         ret = -EINVAL;
1016                         break;
1017                 }
1018
1019                 arg.str = field;
1020                 ret = dynevent_arg_add(cmd, &arg, NULL);
1021                 if (ret)
1022                         break;
1023         }
1024         va_end(args);
1025
1026         return ret;
1027 }
1028 EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
1029
1030 /**
1031  * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
1032  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1033  * @args: Variable number of arg (pairs), one pair for each field
1034  *
1035  * NOTE: Users normally won't want to call this function directly, but
1036  * rather use the kprobe_event_add_fields() wrapper, which
1037  * automatically adds a NULL to the end of the arg list.  If this
1038  * function is used directly, make sure the last arg in the variable
1039  * arg list is NULL.
1040  *
1041  * Add probe fields to an existing kprobe command using a variable
1042  * list of args.  Fields are added in the same order they're listed.
1043  *
1044  * Return: 0 if successful, error otherwise.
1045  */
1046 int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
1047 {
1048         struct dynevent_arg arg;
1049         va_list args;
1050         int ret = 0;
1051
1052         if (cmd->type != DYNEVENT_TYPE_KPROBE)
1053                 return -EINVAL;
1054
1055         dynevent_arg_init(&arg, 0);
1056
1057         va_start(args, cmd);
1058         for (;;) {
1059                 const char *field;
1060
1061                 field = va_arg(args, const char *);
1062                 if (!field)
1063                         break;
1064
1065                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1066                         ret = -EINVAL;
1067                         break;
1068                 }
1069
1070                 arg.str = field;
1071                 ret = dynevent_arg_add(cmd, &arg, NULL);
1072                 if (ret)
1073                         break;
1074         }
1075         va_end(args);
1076
1077         return ret;
1078 }
1079 EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
1080
1081 /**
1082  * kprobe_event_delete - Delete a kprobe event
1083  * @name: The name of the kprobe event to delete
1084  *
1085  * Delete a kprobe event with the give @name from kernel code rather
1086  * than directly from the command line.
1087  *
1088  * Return: 0 if successful, error otherwise.
1089  */
1090 int kprobe_event_delete(const char *name)
1091 {
1092         char buf[MAX_EVENT_NAME_LEN];
1093
1094         snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
1095
1096         return create_or_delete_trace_kprobe(buf);
1097 }
1098 EXPORT_SYMBOL_GPL(kprobe_event_delete);
1099
1100 static int trace_kprobe_release(struct dyn_event *ev)
1101 {
1102         struct trace_kprobe *tk = to_trace_kprobe(ev);
1103         int ret = unregister_trace_kprobe(tk);
1104
1105         if (!ret)
1106                 free_trace_kprobe(tk);
1107         return ret;
1108 }
1109
1110 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
1111 {
1112         struct trace_kprobe *tk = to_trace_kprobe(ev);
1113         int i;
1114
1115         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
1116         if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
1117                 seq_printf(m, "%d", tk->rp.maxactive);
1118         seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
1119                                 trace_probe_name(&tk->tp));
1120
1121         if (!tk->symbol)
1122                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
1123         else if (tk->rp.kp.offset)
1124                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
1125                            tk->rp.kp.offset);
1126         else
1127                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
1128
1129         for (i = 0; i < tk->tp.nr_args; i++)
1130                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
1131         seq_putc(m, '\n');
1132
1133         return 0;
1134 }
1135
1136 static int probes_seq_show(struct seq_file *m, void *v)
1137 {
1138         struct dyn_event *ev = v;
1139
1140         if (!is_trace_kprobe(ev))
1141                 return 0;
1142
1143         return trace_kprobe_show(m, ev);
1144 }
1145
1146 static const struct seq_operations probes_seq_op = {
1147         .start  = dyn_event_seq_start,
1148         .next   = dyn_event_seq_next,
1149         .stop   = dyn_event_seq_stop,
1150         .show   = probes_seq_show
1151 };
1152
1153 static int probes_open(struct inode *inode, struct file *file)
1154 {
1155         int ret;
1156
1157         ret = security_locked_down(LOCKDOWN_TRACEFS);
1158         if (ret)
1159                 return ret;
1160
1161         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1162                 ret = dyn_events_release_all(&trace_kprobe_ops);
1163                 if (ret < 0)
1164                         return ret;
1165         }
1166
1167         return seq_open(file, &probes_seq_op);
1168 }
1169
1170 static ssize_t probes_write(struct file *file, const char __user *buffer,
1171                             size_t count, loff_t *ppos)
1172 {
1173         return trace_parse_run_command(file, buffer, count, ppos,
1174                                        create_or_delete_trace_kprobe);
1175 }
1176
1177 static const struct file_operations kprobe_events_ops = {
1178         .owner          = THIS_MODULE,
1179         .open           = probes_open,
1180         .read           = seq_read,
1181         .llseek         = seq_lseek,
1182         .release        = seq_release,
1183         .write          = probes_write,
1184 };
1185
1186 /* Probes profiling interfaces */
1187 static int probes_profile_seq_show(struct seq_file *m, void *v)
1188 {
1189         struct dyn_event *ev = v;
1190         struct trace_kprobe *tk;
1191
1192         if (!is_trace_kprobe(ev))
1193                 return 0;
1194
1195         tk = to_trace_kprobe(ev);
1196         seq_printf(m, "  %-44s %15lu %15lu\n",
1197                    trace_probe_name(&tk->tp),
1198                    trace_kprobe_nhit(tk),
1199                    tk->rp.kp.nmissed);
1200
1201         return 0;
1202 }
1203
1204 static const struct seq_operations profile_seq_op = {
1205         .start  = dyn_event_seq_start,
1206         .next   = dyn_event_seq_next,
1207         .stop   = dyn_event_seq_stop,
1208         .show   = probes_profile_seq_show
1209 };
1210
1211 static int profile_open(struct inode *inode, struct file *file)
1212 {
1213         int ret;
1214
1215         ret = security_locked_down(LOCKDOWN_TRACEFS);
1216         if (ret)
1217                 return ret;
1218
1219         return seq_open(file, &profile_seq_op);
1220 }
1221
1222 static const struct file_operations kprobe_profile_ops = {
1223         .owner          = THIS_MODULE,
1224         .open           = profile_open,
1225         .read           = seq_read,
1226         .llseek         = seq_lseek,
1227         .release        = seq_release,
1228 };
1229
1230 /* Kprobe specific fetch functions */
1231
1232 /* Return the length of string -- including null terminal byte */
1233 static nokprobe_inline int
1234 fetch_store_strlen_user(unsigned long addr)
1235 {
1236         const void __user *uaddr =  (__force const void __user *)addr;
1237
1238         return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);
1239 }
1240
1241 /* Return the length of string -- including null terminal byte */
1242 static nokprobe_inline int
1243 fetch_store_strlen(unsigned long addr)
1244 {
1245         int ret, len = 0;
1246         u8 c;
1247
1248 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1249         if (addr < TASK_SIZE)
1250                 return fetch_store_strlen_user(addr);
1251 #endif
1252
1253         do {
1254                 ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1);
1255                 len++;
1256         } while (c && ret == 0 && len < MAX_STRING_SIZE);
1257
1258         return (ret < 0) ? ret : len;
1259 }
1260
1261 /*
1262  * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
1263  * with max length and relative data location.
1264  */
1265 static nokprobe_inline int
1266 fetch_store_string_user(unsigned long addr, void *dest, void *base)
1267 {
1268         const void __user *uaddr =  (__force const void __user *)addr;
1269         int maxlen = get_loc_len(*(u32 *)dest);
1270         void *__dest;
1271         long ret;
1272
1273         if (unlikely(!maxlen))
1274                 return -ENOMEM;
1275
1276         __dest = get_loc_data(dest, base);
1277
1278         ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);
1279         if (ret >= 0)
1280                 *(u32 *)dest = make_data_loc(ret, __dest - base);
1281
1282         return ret;
1283 }
1284
1285 /*
1286  * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
1287  * length and relative data location.
1288  */
1289 static nokprobe_inline int
1290 fetch_store_string(unsigned long addr, void *dest, void *base)
1291 {
1292         int maxlen = get_loc_len(*(u32 *)dest);
1293         void *__dest;
1294         long ret;
1295
1296 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1297         if ((unsigned long)addr < TASK_SIZE)
1298                 return fetch_store_string_user(addr, dest, base);
1299 #endif
1300
1301         if (unlikely(!maxlen))
1302                 return -ENOMEM;
1303
1304         __dest = get_loc_data(dest, base);
1305
1306         /*
1307          * Try to get string again, since the string can be changed while
1308          * probing.
1309          */
1310         ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);
1311         if (ret >= 0)
1312                 *(u32 *)dest = make_data_loc(ret, __dest - base);
1313
1314         return ret;
1315 }
1316
1317 static nokprobe_inline int
1318 probe_mem_read_user(void *dest, void *src, size_t size)
1319 {
1320         const void __user *uaddr =  (__force const void __user *)src;
1321
1322         return copy_from_user_nofault(dest, uaddr, size);
1323 }
1324
1325 static nokprobe_inline int
1326 probe_mem_read(void *dest, void *src, size_t size)
1327 {
1328 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1329         if ((unsigned long)src < TASK_SIZE)
1330                 return probe_mem_read_user(dest, src, size);
1331 #endif
1332         return copy_from_kernel_nofault(dest, src, size);
1333 }
1334
1335 /* Note that we don't verify it, since the code does not come from user space */
1336 static int
1337 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
1338                    void *base)
1339 {
1340         unsigned long val;
1341
1342 retry:
1343         /* 1st stage: get value from context */
1344         switch (code->op) {
1345         case FETCH_OP_REG:
1346                 val = regs_get_register(regs, code->param);
1347                 break;
1348         case FETCH_OP_STACK:
1349                 val = regs_get_kernel_stack_nth(regs, code->param);
1350                 break;
1351         case FETCH_OP_STACKP:
1352                 val = kernel_stack_pointer(regs);
1353                 break;
1354         case FETCH_OP_RETVAL:
1355                 val = regs_return_value(regs);
1356                 break;
1357         case FETCH_OP_IMM:
1358                 val = code->immediate;
1359                 break;
1360         case FETCH_OP_COMM:
1361                 val = (unsigned long)current->comm;
1362                 break;
1363         case FETCH_OP_DATA:
1364                 val = (unsigned long)code->data;
1365                 break;
1366 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1367         case FETCH_OP_ARG:
1368                 val = regs_get_kernel_argument(regs, code->param);
1369                 break;
1370 #endif
1371         case FETCH_NOP_SYMBOL:  /* Ignore a place holder */
1372                 code++;
1373                 goto retry;
1374         default:
1375                 return -EILSEQ;
1376         }
1377         code++;
1378
1379         return process_fetch_insn_bottom(code, val, dest, base);
1380 }
1381 NOKPROBE_SYMBOL(process_fetch_insn)
1382
1383 /* Kprobe handler */
1384 static nokprobe_inline void
1385 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1386                     struct trace_event_file *trace_file)
1387 {
1388         struct kprobe_trace_entry_head *entry;
1389         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1390         struct trace_event_buffer fbuffer;
1391         int dsize;
1392
1393         WARN_ON(call != trace_file->event_call);
1394
1395         if (trace_trigger_soft_disabled(trace_file))
1396                 return;
1397
1398         fbuffer.trace_ctx = tracing_gen_ctx();
1399         fbuffer.trace_file = trace_file;
1400
1401         dsize = __get_data_size(&tk->tp, regs);
1402
1403         fbuffer.event =
1404                 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
1405                                         call->event.type,
1406                                         sizeof(*entry) + tk->tp.size + dsize,
1407                                         fbuffer.trace_ctx);
1408         if (!fbuffer.event)
1409                 return;
1410
1411         fbuffer.regs = regs;
1412         entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
1413         entry->ip = (unsigned long)tk->rp.kp.addr;
1414         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1415
1416         trace_event_buffer_commit(&fbuffer);
1417 }
1418
1419 static void
1420 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1421 {
1422         struct event_file_link *link;
1423
1424         trace_probe_for_each_link_rcu(link, &tk->tp)
1425                 __kprobe_trace_func(tk, regs, link->file);
1426 }
1427 NOKPROBE_SYMBOL(kprobe_trace_func);
1428
1429 /* Kretprobe handler */
1430 static nokprobe_inline void
1431 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1432                        struct pt_regs *regs,
1433                        struct trace_event_file *trace_file)
1434 {
1435         struct kretprobe_trace_entry_head *entry;
1436         struct trace_event_buffer fbuffer;
1437         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1438         int dsize;
1439
1440         WARN_ON(call != trace_file->event_call);
1441
1442         if (trace_trigger_soft_disabled(trace_file))
1443                 return;
1444
1445         fbuffer.trace_ctx = tracing_gen_ctx();
1446         fbuffer.trace_file = trace_file;
1447
1448         dsize = __get_data_size(&tk->tp, regs);
1449         fbuffer.event =
1450                 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
1451                                         call->event.type,
1452                                         sizeof(*entry) + tk->tp.size + dsize,
1453                                         fbuffer.trace_ctx);
1454         if (!fbuffer.event)
1455                 return;
1456
1457         fbuffer.regs = regs;
1458         entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
1459         entry->func = (unsigned long)tk->rp.kp.addr;
1460         entry->ret_ip = (unsigned long)ri->ret_addr;
1461         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1462
1463         trace_event_buffer_commit(&fbuffer);
1464 }
1465
1466 static void
1467 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1468                      struct pt_regs *regs)
1469 {
1470         struct event_file_link *link;
1471
1472         trace_probe_for_each_link_rcu(link, &tk->tp)
1473                 __kretprobe_trace_func(tk, ri, regs, link->file);
1474 }
1475 NOKPROBE_SYMBOL(kretprobe_trace_func);
1476
1477 /* Event entry printers */
1478 static enum print_line_t
1479 print_kprobe_event(struct trace_iterator *iter, int flags,
1480                    struct trace_event *event)
1481 {
1482         struct kprobe_trace_entry_head *field;
1483         struct trace_seq *s = &iter->seq;
1484         struct trace_probe *tp;
1485
1486         field = (struct kprobe_trace_entry_head *)iter->ent;
1487         tp = trace_probe_primary_from_call(
1488                 container_of(event, struct trace_event_call, event));
1489         if (WARN_ON_ONCE(!tp))
1490                 goto out;
1491
1492         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1493
1494         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1495                 goto out;
1496
1497         trace_seq_putc(s, ')');
1498
1499         if (print_probe_args(s, tp->args, tp->nr_args,
1500                              (u8 *)&field[1], field) < 0)
1501                 goto out;
1502
1503         trace_seq_putc(s, '\n');
1504  out:
1505         return trace_handle_return(s);
1506 }
1507
1508 static enum print_line_t
1509 print_kretprobe_event(struct trace_iterator *iter, int flags,
1510                       struct trace_event *event)
1511 {
1512         struct kretprobe_trace_entry_head *field;
1513         struct trace_seq *s = &iter->seq;
1514         struct trace_probe *tp;
1515
1516         field = (struct kretprobe_trace_entry_head *)iter->ent;
1517         tp = trace_probe_primary_from_call(
1518                 container_of(event, struct trace_event_call, event));
1519         if (WARN_ON_ONCE(!tp))
1520                 goto out;
1521
1522         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1523
1524         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1525                 goto out;
1526
1527         trace_seq_puts(s, " <- ");
1528
1529         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1530                 goto out;
1531
1532         trace_seq_putc(s, ')');
1533
1534         if (print_probe_args(s, tp->args, tp->nr_args,
1535                              (u8 *)&field[1], field) < 0)
1536                 goto out;
1537
1538         trace_seq_putc(s, '\n');
1539
1540  out:
1541         return trace_handle_return(s);
1542 }
1543
1544
1545 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1546 {
1547         int ret;
1548         struct kprobe_trace_entry_head field;
1549         struct trace_probe *tp;
1550
1551         tp = trace_probe_primary_from_call(event_call);
1552         if (WARN_ON_ONCE(!tp))
1553                 return -ENOENT;
1554
1555         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1556
1557         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1558 }
1559
1560 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1561 {
1562         int ret;
1563         struct kretprobe_trace_entry_head field;
1564         struct trace_probe *tp;
1565
1566         tp = trace_probe_primary_from_call(event_call);
1567         if (WARN_ON_ONCE(!tp))
1568                 return -ENOENT;
1569
1570         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1571         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1572
1573         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1574 }
1575
1576 #ifdef CONFIG_PERF_EVENTS
1577
1578 /* Kprobe profile handler */
1579 static int
1580 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1581 {
1582         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1583         struct kprobe_trace_entry_head *entry;
1584         struct hlist_head *head;
1585         int size, __size, dsize;
1586         int rctx;
1587
1588         if (bpf_prog_array_valid(call)) {
1589                 unsigned long orig_ip = instruction_pointer(regs);
1590                 int ret;
1591
1592                 ret = trace_call_bpf(call, regs);
1593
1594                 /*
1595                  * We need to check and see if we modified the pc of the
1596                  * pt_regs, and if so return 1 so that we don't do the
1597                  * single stepping.
1598                  */
1599                 if (orig_ip != instruction_pointer(regs))
1600                         return 1;
1601                 if (!ret)
1602                         return 0;
1603         }
1604
1605         head = this_cpu_ptr(call->perf_events);
1606         if (hlist_empty(head))
1607                 return 0;
1608
1609         dsize = __get_data_size(&tk->tp, regs);
1610         __size = sizeof(*entry) + tk->tp.size + dsize;
1611         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1612         size -= sizeof(u32);
1613
1614         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1615         if (!entry)
1616                 return 0;
1617
1618         entry->ip = (unsigned long)tk->rp.kp.addr;
1619         memset(&entry[1], 0, dsize);
1620         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1621         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1622                               head, NULL);
1623         return 0;
1624 }
1625 NOKPROBE_SYMBOL(kprobe_perf_func);
1626
1627 /* Kretprobe profile handler */
1628 static void
1629 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1630                     struct pt_regs *regs)
1631 {
1632         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1633         struct kretprobe_trace_entry_head *entry;
1634         struct hlist_head *head;
1635         int size, __size, dsize;
1636         int rctx;
1637
1638         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1639                 return;
1640
1641         head = this_cpu_ptr(call->perf_events);
1642         if (hlist_empty(head))
1643                 return;
1644
1645         dsize = __get_data_size(&tk->tp, regs);
1646         __size = sizeof(*entry) + tk->tp.size + dsize;
1647         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1648         size -= sizeof(u32);
1649
1650         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1651         if (!entry)
1652                 return;
1653
1654         entry->func = (unsigned long)tk->rp.kp.addr;
1655         entry->ret_ip = (unsigned long)ri->ret_addr;
1656         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1657         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1658                               head, NULL);
1659 }
1660 NOKPROBE_SYMBOL(kretprobe_perf_func);
1661
1662 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1663                         const char **symbol, u64 *probe_offset,
1664                         u64 *probe_addr, bool perf_type_tracepoint)
1665 {
1666         const char *pevent = trace_event_name(event->tp_event);
1667         const char *group = event->tp_event->class->system;
1668         struct trace_kprobe *tk;
1669
1670         if (perf_type_tracepoint)
1671                 tk = find_trace_kprobe(pevent, group);
1672         else
1673                 tk = trace_kprobe_primary_from_call(event->tp_event);
1674         if (!tk)
1675                 return -EINVAL;
1676
1677         *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1678                                               : BPF_FD_TYPE_KPROBE;
1679         if (tk->symbol) {
1680                 *symbol = tk->symbol;
1681                 *probe_offset = tk->rp.kp.offset;
1682                 *probe_addr = 0;
1683         } else {
1684                 *symbol = NULL;
1685                 *probe_offset = 0;
1686                 *probe_addr = (unsigned long)tk->rp.kp.addr;
1687         }
1688         return 0;
1689 }
1690 #endif  /* CONFIG_PERF_EVENTS */
1691
1692 /*
1693  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1694  *
1695  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1696  * lockless, but we can't race with this __init function.
1697  */
1698 static int kprobe_register(struct trace_event_call *event,
1699                            enum trace_reg type, void *data)
1700 {
1701         struct trace_event_file *file = data;
1702
1703         switch (type) {
1704         case TRACE_REG_REGISTER:
1705                 return enable_trace_kprobe(event, file);
1706         case TRACE_REG_UNREGISTER:
1707                 return disable_trace_kprobe(event, file);
1708
1709 #ifdef CONFIG_PERF_EVENTS
1710         case TRACE_REG_PERF_REGISTER:
1711                 return enable_trace_kprobe(event, NULL);
1712         case TRACE_REG_PERF_UNREGISTER:
1713                 return disable_trace_kprobe(event, NULL);
1714         case TRACE_REG_PERF_OPEN:
1715         case TRACE_REG_PERF_CLOSE:
1716         case TRACE_REG_PERF_ADD:
1717         case TRACE_REG_PERF_DEL:
1718                 return 0;
1719 #endif
1720         }
1721         return 0;
1722 }
1723
1724 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1725 {
1726         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1727         int ret = 0;
1728
1729         raw_cpu_inc(*tk->nhit);
1730
1731         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1732                 kprobe_trace_func(tk, regs);
1733 #ifdef CONFIG_PERF_EVENTS
1734         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1735                 ret = kprobe_perf_func(tk, regs);
1736 #endif
1737         return ret;
1738 }
1739 NOKPROBE_SYMBOL(kprobe_dispatcher);
1740
1741 static int
1742 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1743 {
1744         struct kretprobe *rp = get_kretprobe(ri);
1745         struct trace_kprobe *tk = container_of(rp, struct trace_kprobe, rp);
1746
1747         raw_cpu_inc(*tk->nhit);
1748
1749         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1750                 kretprobe_trace_func(tk, ri, regs);
1751 #ifdef CONFIG_PERF_EVENTS
1752         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1753                 kretprobe_perf_func(tk, ri, regs);
1754 #endif
1755         return 0;       /* We don't tweak kernel, so just return 0 */
1756 }
1757 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1758
1759 static struct trace_event_functions kretprobe_funcs = {
1760         .trace          = print_kretprobe_event
1761 };
1762
1763 static struct trace_event_functions kprobe_funcs = {
1764         .trace          = print_kprobe_event
1765 };
1766
1767 static struct trace_event_fields kretprobe_fields_array[] = {
1768         { .type = TRACE_FUNCTION_TYPE,
1769           .define_fields = kretprobe_event_define_fields },
1770         {}
1771 };
1772
1773 static struct trace_event_fields kprobe_fields_array[] = {
1774         { .type = TRACE_FUNCTION_TYPE,
1775           .define_fields = kprobe_event_define_fields },
1776         {}
1777 };
1778
1779 static inline void init_trace_event_call(struct trace_kprobe *tk)
1780 {
1781         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1782
1783         if (trace_kprobe_is_return(tk)) {
1784                 call->event.funcs = &kretprobe_funcs;
1785                 call->class->fields_array = kretprobe_fields_array;
1786         } else {
1787                 call->event.funcs = &kprobe_funcs;
1788                 call->class->fields_array = kprobe_fields_array;
1789         }
1790
1791         call->flags = TRACE_EVENT_FL_KPROBE;
1792         call->class->reg = kprobe_register;
1793 }
1794
1795 static int register_kprobe_event(struct trace_kprobe *tk)
1796 {
1797         init_trace_event_call(tk);
1798
1799         return trace_probe_register_event_call(&tk->tp);
1800 }
1801
1802 static int unregister_kprobe_event(struct trace_kprobe *tk)
1803 {
1804         return trace_probe_unregister_event_call(&tk->tp);
1805 }
1806
1807 #ifdef CONFIG_PERF_EVENTS
1808 /* create a trace_kprobe, but don't add it to global lists */
1809 struct trace_event_call *
1810 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1811                           bool is_return)
1812 {
1813         struct trace_kprobe *tk;
1814         int ret;
1815         char *event;
1816
1817         /*
1818          * local trace_kprobes are not added to dyn_event, so they are never
1819          * searched in find_trace_kprobe(). Therefore, there is no concern of
1820          * duplicated name here.
1821          */
1822         event = func ? func : "DUMMY_EVENT";
1823
1824         tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1825                                 offs, 0 /* maxactive */, 0 /* nargs */,
1826                                 is_return);
1827
1828         if (IS_ERR(tk)) {
1829                 pr_info("Failed to allocate trace_probe.(%d)\n",
1830                         (int)PTR_ERR(tk));
1831                 return ERR_CAST(tk);
1832         }
1833
1834         init_trace_event_call(tk);
1835
1836         if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1837                 ret = -ENOMEM;
1838                 goto error;
1839         }
1840
1841         ret = __register_trace_kprobe(tk);
1842         if (ret < 0)
1843                 goto error;
1844
1845         return trace_probe_event_call(&tk->tp);
1846 error:
1847         free_trace_kprobe(tk);
1848         return ERR_PTR(ret);
1849 }
1850
1851 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1852 {
1853         struct trace_kprobe *tk;
1854
1855         tk = trace_kprobe_primary_from_call(event_call);
1856         if (unlikely(!tk))
1857                 return;
1858
1859         if (trace_probe_is_enabled(&tk->tp)) {
1860                 WARN_ON(1);
1861                 return;
1862         }
1863
1864         __unregister_trace_kprobe(tk);
1865
1866         free_trace_kprobe(tk);
1867 }
1868 #endif /* CONFIG_PERF_EVENTS */
1869
1870 static __init void enable_boot_kprobe_events(void)
1871 {
1872         struct trace_array *tr = top_trace_array();
1873         struct trace_event_file *file;
1874         struct trace_kprobe *tk;
1875         struct dyn_event *pos;
1876
1877         mutex_lock(&event_mutex);
1878         for_each_trace_kprobe(tk, pos) {
1879                 list_for_each_entry(file, &tr->events, list)
1880                         if (file->event_call == trace_probe_event_call(&tk->tp))
1881                                 trace_event_enable_disable(file, 1, 0);
1882         }
1883         mutex_unlock(&event_mutex);
1884 }
1885
1886 static __init void setup_boot_kprobe_events(void)
1887 {
1888         char *p, *cmd = kprobe_boot_events_buf;
1889         int ret;
1890
1891         strreplace(kprobe_boot_events_buf, ',', ' ');
1892
1893         while (cmd && *cmd != '\0') {
1894                 p = strchr(cmd, ';');
1895                 if (p)
1896                         *p++ = '\0';
1897
1898                 ret = create_or_delete_trace_kprobe(cmd);
1899                 if (ret)
1900                         pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1901
1902                 cmd = p;
1903         }
1904
1905         enable_boot_kprobe_events();
1906 }
1907
1908 /*
1909  * Register dynevent at core_initcall. This allows kernel to setup kprobe
1910  * events in postcore_initcall without tracefs.
1911  */
1912 static __init int init_kprobe_trace_early(void)
1913 {
1914         int ret;
1915
1916         ret = dyn_event_register(&trace_kprobe_ops);
1917         if (ret)
1918                 return ret;
1919
1920         if (register_module_notifier(&trace_kprobe_module_nb))
1921                 return -EINVAL;
1922
1923         return 0;
1924 }
1925 core_initcall(init_kprobe_trace_early);
1926
1927 /* Make a tracefs interface for controlling probe points */
1928 static __init int init_kprobe_trace(void)
1929 {
1930         int ret;
1931         struct dentry *entry;
1932
1933         ret = tracing_init_dentry();
1934         if (ret)
1935                 return 0;
1936
1937         entry = tracefs_create_file("kprobe_events", 0644, NULL,
1938                                     NULL, &kprobe_events_ops);
1939
1940         /* Event list interface */
1941         if (!entry)
1942                 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1943
1944         /* Profile interface */
1945         entry = tracefs_create_file("kprobe_profile", 0444, NULL,
1946                                     NULL, &kprobe_profile_ops);
1947
1948         if (!entry)
1949                 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1950
1951         setup_boot_kprobe_events();
1952
1953         return 0;
1954 }
1955 fs_initcall(init_kprobe_trace);
1956
1957
1958 #ifdef CONFIG_FTRACE_STARTUP_TEST
1959 static __init struct trace_event_file *
1960 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1961 {
1962         struct trace_event_file *file;
1963
1964         list_for_each_entry(file, &tr->events, list)
1965                 if (file->event_call == trace_probe_event_call(&tk->tp))
1966                         return file;
1967
1968         return NULL;
1969 }
1970
1971 /*
1972  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1973  * stage, we can do this lockless.
1974  */
1975 static __init int kprobe_trace_self_tests_init(void)
1976 {
1977         int ret, warn = 0;
1978         int (*target)(int, int, int, int, int, int);
1979         struct trace_kprobe *tk;
1980         struct trace_event_file *file;
1981
1982         if (tracing_is_disabled())
1983                 return -ENODEV;
1984
1985         if (tracing_selftest_disabled)
1986                 return 0;
1987
1988         target = kprobe_trace_selftest_target;
1989
1990         pr_info("Testing kprobe tracing: ");
1991
1992         ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
1993         if (WARN_ON_ONCE(ret)) {
1994                 pr_warn("error on probing function entry.\n");
1995                 warn++;
1996         } else {
1997                 /* Enable trace point */
1998                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1999                 if (WARN_ON_ONCE(tk == NULL)) {
2000                         pr_warn("error on getting new probe.\n");
2001                         warn++;
2002                 } else {
2003                         file = find_trace_probe_file(tk, top_trace_array());
2004                         if (WARN_ON_ONCE(file == NULL)) {
2005                                 pr_warn("error on getting probe file.\n");
2006                                 warn++;
2007                         } else
2008                                 enable_trace_kprobe(
2009                                         trace_probe_event_call(&tk->tp), file);
2010                 }
2011         }
2012
2013         ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
2014         if (WARN_ON_ONCE(ret)) {
2015                 pr_warn("error on probing function return.\n");
2016                 warn++;
2017         } else {
2018                 /* Enable trace point */
2019                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2020                 if (WARN_ON_ONCE(tk == NULL)) {
2021                         pr_warn("error on getting 2nd new probe.\n");
2022                         warn++;
2023                 } else {
2024                         file = find_trace_probe_file(tk, top_trace_array());
2025                         if (WARN_ON_ONCE(file == NULL)) {
2026                                 pr_warn("error on getting probe file.\n");
2027                                 warn++;
2028                         } else
2029                                 enable_trace_kprobe(
2030                                         trace_probe_event_call(&tk->tp), file);
2031                 }
2032         }
2033
2034         if (warn)
2035                 goto end;
2036
2037         ret = target(1, 2, 3, 4, 5, 6);
2038
2039         /*
2040          * Not expecting an error here, the check is only to prevent the
2041          * optimizer from removing the call to target() as otherwise there
2042          * are no side-effects and the call is never performed.
2043          */
2044         if (ret != 21)
2045                 warn++;
2046
2047         /* Disable trace points before removing it */
2048         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2049         if (WARN_ON_ONCE(tk == NULL)) {
2050                 pr_warn("error on getting test probe.\n");
2051                 warn++;
2052         } else {
2053                 if (trace_kprobe_nhit(tk) != 1) {
2054                         pr_warn("incorrect number of testprobe hits\n");
2055                         warn++;
2056                 }
2057
2058                 file = find_trace_probe_file(tk, top_trace_array());
2059                 if (WARN_ON_ONCE(file == NULL)) {
2060                         pr_warn("error on getting probe file.\n");
2061                         warn++;
2062                 } else
2063                         disable_trace_kprobe(
2064                                 trace_probe_event_call(&tk->tp), file);
2065         }
2066
2067         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2068         if (WARN_ON_ONCE(tk == NULL)) {
2069                 pr_warn("error on getting 2nd test probe.\n");
2070                 warn++;
2071         } else {
2072                 if (trace_kprobe_nhit(tk) != 1) {
2073                         pr_warn("incorrect number of testprobe2 hits\n");
2074                         warn++;
2075                 }
2076
2077                 file = find_trace_probe_file(tk, top_trace_array());
2078                 if (WARN_ON_ONCE(file == NULL)) {
2079                         pr_warn("error on getting probe file.\n");
2080                         warn++;
2081                 } else
2082                         disable_trace_kprobe(
2083                                 trace_probe_event_call(&tk->tp), file);
2084         }
2085
2086         ret = create_or_delete_trace_kprobe("-:testprobe");
2087         if (WARN_ON_ONCE(ret)) {
2088                 pr_warn("error on deleting a probe.\n");
2089                 warn++;
2090         }
2091
2092         ret = create_or_delete_trace_kprobe("-:testprobe2");
2093         if (WARN_ON_ONCE(ret)) {
2094                 pr_warn("error on deleting a probe.\n");
2095                 warn++;
2096         }
2097
2098 end:
2099         ret = dyn_events_release_all(&trace_kprobe_ops);
2100         if (WARN_ON_ONCE(ret)) {
2101                 pr_warn("error on cleaning up probes.\n");
2102                 warn++;
2103         }
2104         /*
2105          * Wait for the optimizer work to finish. Otherwise it might fiddle
2106          * with probes in already freed __init text.
2107          */
2108         wait_for_kprobe_optimizer();
2109         if (warn)
2110                 pr_cont("NG: Some tests are failed. Please check them.\n");
2111         else
2112                 pr_cont("OK\n");
2113         return 0;
2114 }
2115
2116 late_initcall(kprobe_trace_self_tests_init);
2117
2118 #endif