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