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