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 1;
  35 }
  36 __setup("kprobe_event=", set_kprobe_boot_events);
  37
  38 static int trace_kprobe_create(int argc, const char **argv);
  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         mutex_lock(&module_mutex);
 128         ret = !!find_module(tk->symbol);
 129         mutex_unlock(&module_mutex);
 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         /* Will fail if probe is being used by ftrace or perf */
 547         if (unregister_kprobe_event(tk))
 548                 return -EBUSY;
 549
 550 unreg:
 551         __unregister_trace_kprobe(tk);
 552         dyn_event_remove(&tk->devent);
 553         trace_probe_unlink(&tk->tp);
 554
 555         return 0;
 556 }
 557
 558 static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
 559                                          struct trace_kprobe *comp)
 560 {
 561         struct trace_probe_event *tpe = orig->tp.event;
 562         struct trace_probe *pos;
 563         int i;
 564
 565         list_for_each_entry(pos, &tpe->probes, list) {
 566                 orig = container_of(pos, struct trace_kprobe, tp);
 567                 if (strcmp(trace_kprobe_symbol(orig),
 568                            trace_kprobe_symbol(comp)) ||
 569                     trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
 570                         continue;
 571
 572                 /*
 573                  * trace_probe_compare_arg_type() ensured that nr_args and
 574                  * each argument name and type are same. Let's compare comm.
 575                  */
 576                 for (i = 0; i < orig->tp.nr_args; i++) {
 577                         if (strcmp(orig->tp.args[i].comm,
 578                                    comp->tp.args[i].comm))
 579                                 break;
 580                 }
 581
 582                 if (i == orig->tp.nr_args)
 583                         return true;
 584         }
 585
 586         return false;
 587 }
 588
 589 static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
 590 {
 591         int ret;
 592
 593         ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
 594         if (ret) {
 595                 /* Note that argument starts index = 2 */
 596                 trace_probe_log_set_index(ret + 1);
 597                 trace_probe_log_err(0, DIFF_ARG_TYPE);
 598                 return -EEXIST;
 599         }
 600         if (trace_kprobe_has_same_kprobe(to, tk)) {
 601                 trace_probe_log_set_index(0);
 602                 trace_probe_log_err(0, SAME_PROBE);
 603                 return -EEXIST;
 604         }
 605
 606         /* Append to existing event */
 607         ret = trace_probe_append(&tk->tp, &to->tp);
 608         if (ret)
 609                 return ret;
 610
 611         /* Register k*probe */
 612         ret = __register_trace_kprobe(tk);
 613         if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
 614                 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 615                 ret = 0;
 616         }
 617
 618         if (ret)
 619                 trace_probe_unlink(&tk->tp);
 620         else
 621                 dyn_event_add(&tk->devent);
 622
 623         return ret;
 624 }
 625
 626 /* Register a trace_probe and probe_event */
 627 static int register_trace_kprobe(struct trace_kprobe *tk)
 628 {
 629         struct trace_kprobe *old_tk;
 630         int ret;
 631
 632         mutex_lock(&event_mutex);
 633
 634         old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
 635                                    trace_probe_group_name(&tk->tp));
 636         if (old_tk) {
 637                 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
 638                         trace_probe_log_set_index(0);
 639                         trace_probe_log_err(0, DIFF_PROBE_TYPE);
 640                         ret = -EEXIST;
 641                 } else {
 642                         ret = append_trace_kprobe(tk, old_tk);
 643                 }
 644                 goto end;
 645         }
 646
 647         /* Register new event */
 648         ret = register_kprobe_event(tk);
 649         if (ret) {
 650                 if (ret == -EEXIST) {
 651                         trace_probe_log_set_index(0);
 652                         trace_probe_log_err(0, EVENT_EXIST);
 653                 } else
 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);
 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 create_or_delete_trace_kprobe(int argc, char **argv)
 918 {
 919         int ret;
 920
 921         if (argv[0][0] == '-')
 922                 return dyn_event_release(argc, argv, &trace_kprobe_ops);
 923
 924         ret = trace_kprobe_create(argc, (const char **)argv);
 925         return ret == -ECANCELED ? -EINVAL : ret;
 926 }
 927
 928 static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
 929 {
 930         return trace_run_command(cmd->seq.buffer, create_or_delete_trace_kprobe);
 931 }
 932
 933 /**
 934  * kprobe_event_cmd_init - Initialize a kprobe event command object
 935  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 936  * @buf: A pointer to the buffer used to build the command
 937  * @maxlen: The length of the buffer passed in @buf
 938  *
 939  * Initialize a synthetic event command object.  Use this before
 940  * calling any of the other kprobe_event functions.
 941  */
 942 void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
 943 {
 944         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
 945                           trace_kprobe_run_command);
 946 }
 947 EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
 948
 949 /**
 950  * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
 951  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 952  * @kretprobe: Is this a return probe?
 953  * @name: The name of the kprobe event
 954  * @loc: The location of the kprobe event
 955  * @...: Variable number of arg (pairs), one pair for each field
 956  *
 957  * NOTE: Users normally won't want to call this function directly, but
 958  * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
 959  * adds a NULL to the end of the arg list.  If this function is used
 960  * directly, make sure the last arg in the variable arg list is NULL.
 961  *
 962  * Generate a kprobe event command to be executed by
 963  * kprobe_event_gen_cmd_end().  This function can be used to generate the
 964  * complete command or only the first part of it; in the latter case,
 965  * kprobe_event_add_fields() can be used to add more fields following this.
 966  *
 967  * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
 968  * returns -EINVAL if @loc == NULL.
 969  *
 970  * Return: 0 if successful, error otherwise.
 971  */
 972 int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
 973                                  const char *name, const char *loc, ...)
 974 {
 975         char buf[MAX_EVENT_NAME_LEN];
 976         struct dynevent_arg arg;
 977         va_list args;
 978         int ret;
 979
 980         if (cmd->type != DYNEVENT_TYPE_KPROBE)
 981                 return -EINVAL;
 982
 983         if (!loc)
 984                 return -EINVAL;
 985
 986         if (kretprobe)
 987                 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
 988         else
 989                 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
 990
 991         ret = dynevent_str_add(cmd, buf);
 992         if (ret)
 993                 return ret;
 994
 995         dynevent_arg_init(&arg, 0);
 996         arg.str = loc;
 997         ret = dynevent_arg_add(cmd, &arg, NULL);
 998         if (ret)
 999                 return ret;
1000
1001         va_start(args, loc);
1002         for (;;) {
1003                 const char *field;
1004
1005                 field = va_arg(args, const char *);
1006                 if (!field)
1007                         break;
1008
1009                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1010                         ret = -EINVAL;
1011                         break;
1012                 }
1013
1014                 arg.str = field;
1015                 ret = dynevent_arg_add(cmd, &arg, NULL);
1016                 if (ret)
1017                         break;
1018         }
1019         va_end(args);
1020
1021         return ret;
1022 }
1023 EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
1024
1025 /**
1026  * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
1027  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1028  * @...: Variable number of arg (pairs), one pair for each field
1029  *
1030  * NOTE: Users normally won't want to call this function directly, but
1031  * rather use the kprobe_event_add_fields() wrapper, which
1032  * automatically adds a NULL to the end of the arg list.  If this
1033  * function is used directly, make sure the last arg in the variable
1034  * arg list is NULL.
1035  *
1036  * Add probe fields to an existing kprobe command using a variable
1037  * list of args.  Fields are added in the same order they're listed.
1038  *
1039  * Return: 0 if successful, error otherwise.
1040  */
1041 int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
1042 {
1043         struct dynevent_arg arg;
1044         va_list args;
1045         int ret = 0;
1046
1047         if (cmd->type != DYNEVENT_TYPE_KPROBE)
1048                 return -EINVAL;
1049
1050         dynevent_arg_init(&arg, 0);
1051
1052         va_start(args, cmd);
1053         for (;;) {
1054                 const char *field;
1055
1056                 field = va_arg(args, const char *);
1057                 if (!field)
1058                         break;
1059
1060                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1061                         ret = -EINVAL;
1062                         break;
1063                 }
1064
1065                 arg.str = field;
1066                 ret = dynevent_arg_add(cmd, &arg, NULL);
1067                 if (ret)
1068                         break;
1069         }
1070         va_end(args);
1071
1072         return ret;
1073 }
1074 EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
1075
1076 /**
1077  * kprobe_event_delete - Delete a kprobe event
1078  * @name: The name of the kprobe event to delete
1079  *
1080  * Delete a kprobe event with the give @name from kernel code rather
1081  * than directly from the command line.
1082  *
1083  * Return: 0 if successful, error otherwise.
1084  */
1085 int kprobe_event_delete(const char *name)
1086 {
1087         char buf[MAX_EVENT_NAME_LEN];
1088
1089         snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
1090
1091         return trace_run_command(buf, create_or_delete_trace_kprobe);
1092 }
1093 EXPORT_SYMBOL_GPL(kprobe_event_delete);
1094
1095 static int trace_kprobe_release(struct dyn_event *ev)
1096 {
1097         struct trace_kprobe *tk = to_trace_kprobe(ev);
1098         int ret = unregister_trace_kprobe(tk);
1099
1100         if (!ret)
1101                 free_trace_kprobe(tk);
1102         return ret;
1103 }
1104
1105 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
1106 {
1107         struct trace_kprobe *tk = to_trace_kprobe(ev);
1108         int i;
1109
1110         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
1111         if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
1112                 seq_printf(m, "%d", tk->rp.maxactive);
1113         seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
1114                                 trace_probe_name(&tk->tp));
1115
1116         if (!tk->symbol)
1117                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
1118         else if (tk->rp.kp.offset)
1119                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
1120                            tk->rp.kp.offset);
1121         else
1122                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
1123
1124         for (i = 0; i < tk->tp.nr_args; i++)
1125                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
1126         seq_putc(m, '\n');
1127
1128         return 0;
1129 }
1130
1131 static int probes_seq_show(struct seq_file *m, void *v)
1132 {
1133         struct dyn_event *ev = v;
1134
1135         if (!is_trace_kprobe(ev))
1136                 return 0;
1137
1138         return trace_kprobe_show(m, ev);
1139 }
1140
1141 static const struct seq_operations probes_seq_op = {
1142         .start  = dyn_event_seq_start,
1143         .next   = dyn_event_seq_next,
1144         .stop   = dyn_event_seq_stop,
1145         .show   = probes_seq_show
1146 };
1147
1148 static int probes_open(struct inode *inode, struct file *file)
1149 {
1150         int ret;
1151
1152         ret = security_locked_down(LOCKDOWN_TRACEFS);
1153         if (ret)
1154                 return ret;
1155
1156         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1157                 ret = dyn_events_release_all(&trace_kprobe_ops);
1158                 if (ret < 0)
1159                         return ret;
1160         }
1161
1162         return seq_open(file, &probes_seq_op);
1163 }
1164
1165 static ssize_t probes_write(struct file *file, const char __user *buffer,
1166                             size_t count, loff_t *ppos)
1167 {
1168         return trace_parse_run_command(file, buffer, count, ppos,
1169                                        create_or_delete_trace_kprobe);
1170 }
1171
1172 static const struct file_operations kprobe_events_ops = {
1173         .owner          = THIS_MODULE,
1174         .open           = probes_open,
1175         .read           = seq_read,
1176         .llseek         = seq_lseek,
1177         .release        = seq_release,
1178         .write          = probes_write,
1179 };
1180
1181 /* Probes profiling interfaces */
1182 static int probes_profile_seq_show(struct seq_file *m, void *v)
1183 {
1184         struct dyn_event *ev = v;
1185         struct trace_kprobe *tk;
1186         unsigned long nmissed;
1187
1188         if (!is_trace_kprobe(ev))
1189                 return 0;
1190
1191         tk = to_trace_kprobe(ev);
1192         nmissed = trace_kprobe_is_return(tk) ?
1193                 tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed;
1194         seq_printf(m, "  %-44s %15lu %15lu\n",
1195                    trace_probe_name(&tk->tp),
1196                    trace_kprobe_nhit(tk),
1197                    nmissed);
1198
1199         return 0;
1200 }
1201
1202 static const struct seq_operations profile_seq_op = {
1203         .start  = dyn_event_seq_start,
1204         .next   = dyn_event_seq_next,
1205         .stop   = dyn_event_seq_stop,
1206         .show   = probes_profile_seq_show
1207 };
1208
1209 static int profile_open(struct inode *inode, struct file *file)
1210 {
1211         int ret;
1212
1213         ret = security_locked_down(LOCKDOWN_TRACEFS);
1214         if (ret)
1215                 return ret;
1216
1217         return seq_open(file, &profile_seq_op);
1218 }
1219
1220 static const struct file_operations kprobe_profile_ops = {
1221         .owner          = THIS_MODULE,
1222         .open           = profile_open,
1223         .read           = seq_read,
1224         .llseek         = seq_lseek,
1225         .release        = seq_release,
1226 };
1227
1228 /* Kprobe specific fetch functions */
1229
1230 /* Return the length of string -- including null terminal byte */
1231 static nokprobe_inline int
1232 fetch_store_strlen_user(unsigned long addr)
1233 {
1234         const void __user *uaddr =  (__force const void __user *)addr;
1235
1236         return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);
1237 }
1238
1239 /* Return the length of string -- including null terminal byte */
1240 static nokprobe_inline int
1241 fetch_store_strlen(unsigned long addr)
1242 {
1243         int ret, len = 0;
1244         u8 c;
1245
1246 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1247         if (addr < TASK_SIZE)
1248                 return fetch_store_strlen_user(addr);
1249 #endif
1250
1251         do {
1252                 ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1);
1253                 len++;
1254         } while (c && ret == 0 && len < MAX_STRING_SIZE);
1255
1256         return (ret < 0) ? ret : len;
1257 }
1258
1259 /*
1260  * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
1261  * with max length and relative data location.
1262  */
1263 static nokprobe_inline int
1264 fetch_store_string_user(unsigned long addr, void *dest, void *base)
1265 {
1266         const void __user *uaddr =  (__force const void __user *)addr;
1267         int maxlen = get_loc_len(*(u32 *)dest);
1268         void *__dest;
1269         long ret;
1270
1271         if (unlikely(!maxlen))
1272                 return -ENOMEM;
1273
1274         __dest = get_loc_data(dest, base);
1275
1276         ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);
1277         if (ret >= 0)
1278                 *(u32 *)dest = make_data_loc(ret, __dest - base);
1279
1280         return ret;
1281 }
1282
1283 /*
1284  * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
1285  * length and relative data location.
1286  */
1287 static nokprobe_inline int
1288 fetch_store_string(unsigned long addr, void *dest, void *base)
1289 {
1290         int maxlen = get_loc_len(*(u32 *)dest);
1291         void *__dest;
1292         long ret;
1293
1294 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1295         if ((unsigned long)addr < TASK_SIZE)
1296                 return fetch_store_string_user(addr, dest, base);
1297 #endif
1298
1299         if (unlikely(!maxlen))
1300                 return -ENOMEM;
1301
1302         __dest = get_loc_data(dest, base);
1303
1304         /*
1305          * Try to get string again, since the string can be changed while
1306          * probing.
1307          */
1308         ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);
1309         if (ret >= 0)
1310                 *(u32 *)dest = make_data_loc(ret, __dest - base);
1311
1312         return ret;
1313 }
1314
1315 static nokprobe_inline int
1316 probe_mem_read_user(void *dest, void *src, size_t size)
1317 {
1318         const void __user *uaddr =  (__force const void __user *)src;
1319
1320         return copy_from_user_nofault(dest, uaddr, size);
1321 }
1322
1323 static nokprobe_inline int
1324 probe_mem_read(void *dest, void *src, size_t size)
1325 {
1326 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1327         if ((unsigned long)src < TASK_SIZE)
1328                 return probe_mem_read_user(dest, src, size);
1329 #endif
1330         return copy_from_kernel_nofault(dest, src, size);
1331 }
1332
1333 /* Note that we don't verify it, since the code does not come from user space */
1334 static int
1335 process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
1336                    void *base)
1337 {
1338         struct pt_regs *regs = rec;
1339         unsigned long val;
1340
1341 retry:
1342         /* 1st stage: get value from context */
1343         switch (code->op) {
1344         case FETCH_OP_REG:
1345                 val = regs_get_register(regs, code->param);
1346                 break;
1347         case FETCH_OP_STACK:
1348                 val = regs_get_kernel_stack_nth(regs, code->param);
1349                 break;
1350         case FETCH_OP_STACKP:
1351                 val = kernel_stack_pointer(regs);
1352                 break;
1353         case FETCH_OP_RETVAL:
1354                 val = regs_return_value(regs);
1355                 break;
1356         case FETCH_OP_IMM:
1357                 val = code->immediate;
1358                 break;
1359         case FETCH_OP_COMM:
1360                 val = (unsigned long)current->comm;
1361                 break;
1362         case FETCH_OP_DATA:
1363                 val = (unsigned long)code->data;
1364                 break;
1365 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1366         case FETCH_OP_ARG:
1367                 val = regs_get_kernel_argument(regs, code->param);
1368                 break;
1369 #endif
1370         case FETCH_NOP_SYMBOL:  /* Ignore a place holder */
1371                 code++;
1372                 goto retry;
1373         default:
1374                 return -EILSEQ;
1375         }
1376         code++;
1377
1378         return process_fetch_insn_bottom(code, val, dest, base);
1379 }
1380 NOKPROBE_SYMBOL(process_fetch_insn)
1381
1382 /* Kprobe handler */
1383 static nokprobe_inline void
1384 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1385                     struct trace_event_file *trace_file)
1386 {
1387         struct kprobe_trace_entry_head *entry;
1388         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1389         struct trace_event_buffer fbuffer;
1390         int dsize;
1391
1392         WARN_ON(call != trace_file->event_call);
1393
1394         if (trace_trigger_soft_disabled(trace_file))
1395                 return;
1396
1397         local_save_flags(fbuffer.flags);
1398         fbuffer.pc = preempt_count();
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.flags, fbuffer.pc);
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         local_save_flags(fbuffer.flags);
1446         fbuffer.pc = preempt_count();
1447         fbuffer.trace_file = trace_file;
1448
1449         dsize = __get_data_size(&tk->tp, regs);
1450         fbuffer.event =
1451                 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
1452                                         call->event.type,
1453                                         sizeof(*entry) + tk->tp.size + dsize,
1454                                         fbuffer.flags, fbuffer.pc);
1455         if (!fbuffer.event)
1456                 return;
1457
1458         fbuffer.regs = regs;
1459         entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
1460         entry->func = (unsigned long)tk->rp.kp.addr;
1461         entry->ret_ip = (unsigned long)ri->ret_addr;
1462         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1463
1464         trace_event_buffer_commit(&fbuffer);
1465 }
1466
1467 static void
1468 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1469                      struct pt_regs *regs)
1470 {
1471         struct event_file_link *link;
1472
1473         trace_probe_for_each_link_rcu(link, &tk->tp)
1474                 __kretprobe_trace_func(tk, ri, regs, link->file);
1475 }
1476 NOKPROBE_SYMBOL(kretprobe_trace_func);
1477
1478 /* Event entry printers */
1479 static enum print_line_t
1480 print_kprobe_event(struct trace_iterator *iter, int flags,
1481                    struct trace_event *event)
1482 {
1483         struct kprobe_trace_entry_head *field;
1484         struct trace_seq *s = &iter->seq;
1485         struct trace_probe *tp;
1486
1487         field = (struct kprobe_trace_entry_head *)iter->ent;
1488         tp = trace_probe_primary_from_call(
1489                 container_of(event, struct trace_event_call, event));
1490         if (WARN_ON_ONCE(!tp))
1491                 goto out;
1492
1493         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1494
1495         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1496                 goto out;
1497
1498         trace_seq_putc(s, ')');
1499
1500         if (print_probe_args(s, tp->args, tp->nr_args,
1501                              (u8 *)&field[1], field) < 0)
1502                 goto out;
1503
1504         trace_seq_putc(s, '\n');
1505  out:
1506         return trace_handle_return(s);
1507 }
1508
1509 static enum print_line_t
1510 print_kretprobe_event(struct trace_iterator *iter, int flags,
1511                       struct trace_event *event)
1512 {
1513         struct kretprobe_trace_entry_head *field;
1514         struct trace_seq *s = &iter->seq;
1515         struct trace_probe *tp;
1516
1517         field = (struct kretprobe_trace_entry_head *)iter->ent;
1518         tp = trace_probe_primary_from_call(
1519                 container_of(event, struct trace_event_call, event));
1520         if (WARN_ON_ONCE(!tp))
1521                 goto out;
1522
1523         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1524
1525         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1526                 goto out;
1527
1528         trace_seq_puts(s, " <- ");
1529
1530         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1531                 goto out;
1532
1533         trace_seq_putc(s, ')');
1534
1535         if (print_probe_args(s, tp->args, tp->nr_args,
1536                              (u8 *)&field[1], field) < 0)
1537                 goto out;
1538
1539         trace_seq_putc(s, '\n');
1540
1541  out:
1542         return trace_handle_return(s);
1543 }
1544
1545
1546 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1547 {
1548         int ret;
1549         struct kprobe_trace_entry_head field;
1550         struct trace_probe *tp;
1551
1552         tp = trace_probe_primary_from_call(event_call);
1553         if (WARN_ON_ONCE(!tp))
1554                 return -ENOENT;
1555
1556         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1557
1558         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1559 }
1560
1561 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1562 {
1563         int ret;
1564         struct kretprobe_trace_entry_head field;
1565         struct trace_probe *tp;
1566
1567         tp = trace_probe_primary_from_call(event_call);
1568         if (WARN_ON_ONCE(!tp))
1569                 return -ENOENT;
1570
1571         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1572         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1573
1574         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1575 }
1576
1577 #ifdef CONFIG_PERF_EVENTS
1578
1579 /* Kprobe profile handler */
1580 static int
1581 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1582 {
1583         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1584         struct kprobe_trace_entry_head *entry;
1585         struct hlist_head *head;
1586         int size, __size, dsize;
1587         int rctx;
1588
1589         if (bpf_prog_array_valid(call)) {
1590                 unsigned long orig_ip = instruction_pointer(regs);
1591                 int ret;
1592
1593                 ret = trace_call_bpf(call, regs);
1594
1595                 /*
1596                  * We need to check and see if we modified the pc of the
1597                  * pt_regs, and if so return 1 so that we don't do the
1598                  * single stepping.
1599                  */
1600                 if (orig_ip != instruction_pointer(regs))
1601                         return 1;
1602                 if (!ret)
1603                         return 0;
1604         }
1605
1606         head = this_cpu_ptr(call->perf_events);
1607         if (hlist_empty(head))
1608                 return 0;
1609
1610         dsize = __get_data_size(&tk->tp, regs);
1611         __size = sizeof(*entry) + tk->tp.size + dsize;
1612         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1613         size -= sizeof(u32);
1614
1615         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1616         if (!entry)
1617                 return 0;
1618
1619         entry->ip = (unsigned long)tk->rp.kp.addr;
1620         memset(&entry[1], 0, dsize);
1621         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1622         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1623                               head, NULL);
1624         return 0;
1625 }
1626 NOKPROBE_SYMBOL(kprobe_perf_func);
1627
1628 /* Kretprobe profile handler */
1629 static void
1630 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1631                     struct pt_regs *regs)
1632 {
1633         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1634         struct kretprobe_trace_entry_head *entry;
1635         struct hlist_head *head;
1636         int size, __size, dsize;
1637         int rctx;
1638
1639         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1640                 return;
1641
1642         head = this_cpu_ptr(call->perf_events);
1643         if (hlist_empty(head))
1644                 return;
1645
1646         dsize = __get_data_size(&tk->tp, regs);
1647         __size = sizeof(*entry) + tk->tp.size + dsize;
1648         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1649         size -= sizeof(u32);
1650
1651         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1652         if (!entry)
1653                 return;
1654
1655         entry->func = (unsigned long)tk->rp.kp.addr;
1656         entry->ret_ip = (unsigned long)ri->ret_addr;
1657         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1658         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1659                               head, NULL);
1660 }
1661 NOKPROBE_SYMBOL(kretprobe_perf_func);
1662
1663 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1664                         const char **symbol, u64 *probe_offset,
1665                         u64 *probe_addr, bool perf_type_tracepoint)
1666 {
1667         const char *pevent = trace_event_name(event->tp_event);
1668         const char *group = event->tp_event->class->system;
1669         struct trace_kprobe *tk;
1670
1671         if (perf_type_tracepoint)
1672                 tk = find_trace_kprobe(pevent, group);
1673         else
1674                 tk = trace_kprobe_primary_from_call(event->tp_event);
1675         if (!tk)
1676                 return -EINVAL;
1677
1678         *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1679                                               : BPF_FD_TYPE_KPROBE;
1680         if (tk->symbol) {
1681                 *symbol = tk->symbol;
1682                 *probe_offset = tk->rp.kp.offset;
1683                 *probe_addr = 0;
1684         } else {
1685                 *symbol = NULL;
1686                 *probe_offset = 0;
1687                 *probe_addr = (unsigned long)tk->rp.kp.addr;
1688         }
1689         return 0;
1690 }
1691 #endif  /* CONFIG_PERF_EVENTS */
1692
1693 /*
1694  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1695  *
1696  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1697  * lockless, but we can't race with this __init function.
1698  */
1699 static int kprobe_register(struct trace_event_call *event,
1700                            enum trace_reg type, void *data)
1701 {
1702         struct trace_event_file *file = data;
1703
1704         switch (type) {
1705         case TRACE_REG_REGISTER:
1706                 return enable_trace_kprobe(event, file);
1707         case TRACE_REG_UNREGISTER:
1708                 return disable_trace_kprobe(event, file);
1709
1710 #ifdef CONFIG_PERF_EVENTS
1711         case TRACE_REG_PERF_REGISTER:
1712                 return enable_trace_kprobe(event, NULL);
1713         case TRACE_REG_PERF_UNREGISTER:
1714                 return disable_trace_kprobe(event, NULL);
1715         case TRACE_REG_PERF_OPEN:
1716         case TRACE_REG_PERF_CLOSE:
1717         case TRACE_REG_PERF_ADD:
1718         case TRACE_REG_PERF_DEL:
1719                 return 0;
1720 #endif
1721         }
1722         return 0;
1723 }
1724
1725 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1726 {
1727         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1728         int ret = 0;
1729
1730         raw_cpu_inc(*tk->nhit);
1731
1732         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1733                 kprobe_trace_func(tk, regs);
1734 #ifdef CONFIG_PERF_EVENTS
1735         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1736                 ret = kprobe_perf_func(tk, regs);
1737 #endif
1738         return ret;
1739 }
1740 NOKPROBE_SYMBOL(kprobe_dispatcher);
1741
1742 static int
1743 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1744 {
1745         struct trace_kprobe *tk = container_of(ri->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 tweek 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 = trace_run_command(cmd, create_or_delete_trace_kprobe);
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 = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)",
1993                                 create_or_delete_trace_kprobe);
1994         if (WARN_ON_ONCE(ret)) {
1995                 pr_warn("error on probing function entry.\n");
1996                 warn++;
1997         } else {
1998                 /* Enable trace point */
1999                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2000                 if (WARN_ON_ONCE(tk == NULL)) {
2001                         pr_warn("error on getting new probe.\n");
2002                         warn++;
2003                 } else {
2004                         file = find_trace_probe_file(tk, top_trace_array());
2005                         if (WARN_ON_ONCE(file == NULL)) {
2006                                 pr_warn("error on getting probe file.\n");
2007                                 warn++;
2008                         } else
2009                                 enable_trace_kprobe(
2010                                         trace_probe_event_call(&tk->tp), file);
2011                 }
2012         }
2013
2014         ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval",
2015                                 create_or_delete_trace_kprobe);
2016         if (WARN_ON_ONCE(ret)) {
2017                 pr_warn("error on probing function return.\n");
2018                 warn++;
2019         } else {
2020                 /* Enable trace point */
2021                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2022                 if (WARN_ON_ONCE(tk == NULL)) {
2023                         pr_warn("error on getting 2nd new probe.\n");
2024                         warn++;
2025                 } else {
2026                         file = find_trace_probe_file(tk, top_trace_array());
2027                         if (WARN_ON_ONCE(file == NULL)) {
2028                                 pr_warn("error on getting probe file.\n");
2029                                 warn++;
2030                         } else
2031                                 enable_trace_kprobe(
2032                                         trace_probe_event_call(&tk->tp), file);
2033                 }
2034         }
2035
2036         if (warn)
2037                 goto end;
2038
2039         ret = target(1, 2, 3, 4, 5, 6);
2040
2041         /*
2042          * Not expecting an error here, the check is only to prevent the
2043          * optimizer from removing the call to target() as otherwise there
2044          * are no side-effects and the call is never performed.
2045          */
2046         if (ret != 21)
2047                 warn++;
2048
2049         /* Disable trace points before removing it */
2050         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2051         if (WARN_ON_ONCE(tk == NULL)) {
2052                 pr_warn("error on getting test probe.\n");
2053                 warn++;
2054         } else {
2055                 if (trace_kprobe_nhit(tk) != 1) {
2056                         pr_warn("incorrect number of testprobe hits\n");
2057                         warn++;
2058                 }
2059
2060                 file = find_trace_probe_file(tk, top_trace_array());
2061                 if (WARN_ON_ONCE(file == NULL)) {
2062                         pr_warn("error on getting probe file.\n");
2063                         warn++;
2064                 } else
2065                         disable_trace_kprobe(
2066                                 trace_probe_event_call(&tk->tp), file);
2067         }
2068
2069         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2070         if (WARN_ON_ONCE(tk == NULL)) {
2071                 pr_warn("error on getting 2nd test probe.\n");
2072                 warn++;
2073         } else {
2074                 if (trace_kprobe_nhit(tk) != 1) {
2075                         pr_warn("incorrect number of testprobe2 hits\n");
2076                         warn++;
2077                 }
2078
2079                 file = find_trace_probe_file(tk, top_trace_array());
2080                 if (WARN_ON_ONCE(file == NULL)) {
2081                         pr_warn("error on getting probe file.\n");
2082                         warn++;
2083                 } else
2084                         disable_trace_kprobe(
2085                                 trace_probe_event_call(&tk->tp), file);
2086         }
2087
2088         ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe);
2089         if (WARN_ON_ONCE(ret)) {
2090                 pr_warn("error on deleting a probe.\n");
2091                 warn++;
2092         }
2093
2094         ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe);
2095         if (WARN_ON_ONCE(ret)) {
2096                 pr_warn("error on deleting a probe.\n");
2097                 warn++;
2098         }
2099
2100 end:
2101         ret = dyn_events_release_all(&trace_kprobe_ops);
2102         if (WARN_ON_ONCE(ret)) {
2103                 pr_warn("error on cleaning up probes.\n");
2104                 warn++;
2105         }
2106         /*
2107          * Wait for the optimizer work to finish. Otherwise it might fiddle
2108          * with probes in already freed __init text.
2109          */
2110         wait_for_kprobe_optimizer();
2111         if (warn)
2112                 pr_cont("NG: Some tests are failed. Please check them.\n");
2113         else
2114                 pr_cont("OK\n");
2115         return 0;
2116 }
2117
2118 late_initcall(kprobe_trace_self_tests_init);
2119
2120 #endif