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