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         strscpy(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 #ifdef CONFIG_MODULES
 115 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
 116 {
 117         char *p;
 118         bool ret;
 119
 120         if (!tk->symbol)
 121                 return false;
 122         p = strchr(tk->symbol, ':');
 123         if (!p)
 124                 return true;
 125         *p = '\0';
 126         rcu_read_lock_sched();
 127         ret = !!find_module(tk->symbol);
 128         rcu_read_unlock_sched();
 129         *p = ':';
 130
 131         return ret;
 132 }
 133 #else
 134 static inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
 135 {
 136         return false;
 137 }
 138 #endif
 139
 140 static bool trace_kprobe_is_busy(struct dyn_event *ev)
 141 {
 142         struct trace_kprobe *tk = to_trace_kprobe(ev);
 143
 144         return trace_probe_is_enabled(&tk->tp);
 145 }
 146
 147 static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
 148                                             int argc, const char **argv)
 149 {
 150         char buf[MAX_ARGSTR_LEN + 1];
 151
 152         if (!argc)
 153                 return true;
 154
 155         if (!tk->symbol)
 156                 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
 157         else if (tk->rp.kp.offset)
 158                 snprintf(buf, sizeof(buf), "%s+%u",
 159                          trace_kprobe_symbol(tk), tk->rp.kp.offset);
 160         else
 161                 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
 162         if (strcmp(buf, argv[0]))
 163                 return false;
 164         argc--; argv++;
 165
 166         return trace_probe_match_command_args(&tk->tp, argc, argv);
 167 }
 168
 169 static bool trace_kprobe_match(const char *system, const char *event,
 170                         int argc, const char **argv, struct dyn_event *ev)
 171 {
 172         struct trace_kprobe *tk = to_trace_kprobe(ev);
 173
 174         return (event[0] == '\0' ||
 175                 strcmp(trace_probe_name(&tk->tp), event) == 0) &&
 176             (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
 177             trace_kprobe_match_command_head(tk, argc, argv);
 178 }
 179
 180 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
 181 {
 182         unsigned long nhit = 0;
 183         int cpu;
 184
 185         for_each_possible_cpu(cpu)
 186                 nhit += *per_cpu_ptr(tk->nhit, cpu);
 187
 188         return nhit;
 189 }
 190
 191 static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk)
 192 {
 193         return !(list_empty(&tk->rp.kp.list) &&
 194                  hlist_unhashed(&tk->rp.kp.hlist));
 195 }
 196
 197 /* Return 0 if it fails to find the symbol address */
 198 static nokprobe_inline
 199 unsigned long trace_kprobe_address(struct trace_kprobe *tk)
 200 {
 201         unsigned long addr;
 202
 203         if (tk->symbol) {
 204                 addr = (unsigned long)
 205                         kallsyms_lookup_name(trace_kprobe_symbol(tk));
 206                 if (addr)
 207                         addr += tk->rp.kp.offset;
 208         } else {
 209                 addr = (unsigned long)tk->rp.kp.addr;
 210         }
 211         return addr;
 212 }
 213
 214 static nokprobe_inline struct trace_kprobe *
 215 trace_kprobe_primary_from_call(struct trace_event_call *call)
 216 {
 217         struct trace_probe *tp;
 218
 219         tp = trace_probe_primary_from_call(call);
 220         if (WARN_ON_ONCE(!tp))
 221                 return NULL;
 222
 223         return container_of(tp, struct trace_kprobe, tp);
 224 }
 225
 226 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
 227 {
 228         struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
 229
 230         return tk ? (kprobe_on_func_entry(tk->rp.kp.addr,
 231                         tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
 232                         tk->rp.kp.addr ? 0 : tk->rp.kp.offset) == 0) : false;
 233 }
 234
 235 bool trace_kprobe_error_injectable(struct trace_event_call *call)
 236 {
 237         struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
 238
 239         return tk ? within_error_injection_list(trace_kprobe_address(tk)) :
 240                false;
 241 }
 242
 243 static int register_kprobe_event(struct trace_kprobe *tk);
 244 static int unregister_kprobe_event(struct trace_kprobe *tk);
 245
 246 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 247 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 248                                 struct pt_regs *regs);
 249
 250 static void free_trace_kprobe(struct trace_kprobe *tk)
 251 {
 252         if (tk) {
 253                 trace_probe_cleanup(&tk->tp);
 254                 kfree(tk->symbol);
 255                 free_percpu(tk->nhit);
 256                 kfree(tk);
 257         }
 258 }
 259
 260 /*
 261  * Allocate new trace_probe and initialize it (including kprobes).
 262  */
 263 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
 264                                              const char *event,
 265                                              void *addr,
 266                                              const char *symbol,
 267                                              unsigned long offs,
 268                                              int maxactive,
 269                                              int nargs, bool is_return)
 270 {
 271         struct trace_kprobe *tk;
 272         int ret = -ENOMEM;
 273
 274         tk = kzalloc(struct_size(tk, tp.args, nargs), GFP_KERNEL);
 275         if (!tk)
 276                 return ERR_PTR(ret);
 277
 278         tk->nhit = alloc_percpu(unsigned long);
 279         if (!tk->nhit)
 280                 goto error;
 281
 282         if (symbol) {
 283                 tk->symbol = kstrdup(symbol, GFP_KERNEL);
 284                 if (!tk->symbol)
 285                         goto error;
 286                 tk->rp.kp.symbol_name = tk->symbol;
 287                 tk->rp.kp.offset = offs;
 288         } else
 289                 tk->rp.kp.addr = addr;
 290
 291         if (is_return)
 292                 tk->rp.handler = kretprobe_dispatcher;
 293         else
 294                 tk->rp.kp.pre_handler = kprobe_dispatcher;
 295
 296         tk->rp.maxactive = maxactive;
 297         INIT_HLIST_NODE(&tk->rp.kp.hlist);
 298         INIT_LIST_HEAD(&tk->rp.kp.list);
 299
 300         ret = trace_probe_init(&tk->tp, event, group, false, nargs);
 301         if (ret < 0)
 302                 goto error;
 303
 304         dyn_event_init(&tk->devent, &trace_kprobe_ops);
 305         return tk;
 306 error:
 307         free_trace_kprobe(tk);
 308         return ERR_PTR(ret);
 309 }
 310
 311 static struct trace_kprobe *find_trace_kprobe(const char *event,
 312                                               const char *group)
 313 {
 314         struct dyn_event *pos;
 315         struct trace_kprobe *tk;
 316
 317         for_each_trace_kprobe(tk, pos)
 318                 if (strcmp(trace_probe_name(&tk->tp), event) == 0 &&
 319                     strcmp(trace_probe_group_name(&tk->tp), group) == 0)
 320                         return tk;
 321         return NULL;
 322 }
 323
 324 static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
 325 {
 326         int ret = 0;
 327
 328         if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) {
 329                 if (trace_kprobe_is_return(tk))
 330                         ret = enable_kretprobe(&tk->rp);
 331                 else
 332                         ret = enable_kprobe(&tk->rp.kp);
 333         }
 334
 335         return ret;
 336 }
 337
 338 static void __disable_trace_kprobe(struct trace_probe *tp)
 339 {
 340         struct trace_kprobe *tk;
 341
 342         list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) {
 343                 if (!trace_kprobe_is_registered(tk))
 344                         continue;
 345                 if (trace_kprobe_is_return(tk))
 346                         disable_kretprobe(&tk->rp);
 347                 else
 348                         disable_kprobe(&tk->rp.kp);
 349         }
 350 }
 351
 352 /*
 353  * Enable trace_probe
 354  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
 355  */
 356 static int enable_trace_kprobe(struct trace_event_call *call,
 357                                 struct trace_event_file *file)
 358 {
 359         struct trace_probe *tp;
 360         struct trace_kprobe *tk;
 361         bool enabled;
 362         int ret = 0;
 363
 364         tp = trace_probe_primary_from_call(call);
 365         if (WARN_ON_ONCE(!tp))
 366                 return -ENODEV;
 367         enabled = trace_probe_is_enabled(tp);
 368
 369         /* This also changes "enabled" state */
 370         if (file) {
 371                 ret = trace_probe_add_file(tp, file);
 372                 if (ret)
 373                         return ret;
 374         } else
 375                 trace_probe_set_flag(tp, TP_FLAG_PROFILE);
 376
 377         if (enabled)
 378                 return 0;
 379
 380         list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) {
 381                 if (trace_kprobe_has_gone(tk))
 382                         continue;
 383                 ret = __enable_trace_kprobe(tk);
 384                 if (ret)
 385                         break;
 386                 enabled = true;
 387         }
 388
 389         if (ret) {
 390                 /* Failed to enable one of them. Roll back all */
 391                 if (enabled)
 392                         __disable_trace_kprobe(tp);
 393                 if (file)
 394                         trace_probe_remove_file(tp, file);
 395                 else
 396                         trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
 397         }
 398
 399         return ret;
 400 }
 401
 402 /*
 403  * Disable trace_probe
 404  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
 405  */
 406 static int disable_trace_kprobe(struct trace_event_call *call,
 407                                 struct trace_event_file *file)
 408 {
 409         struct trace_probe *tp;
 410
 411         tp = trace_probe_primary_from_call(call);
 412         if (WARN_ON_ONCE(!tp))
 413                 return -ENODEV;
 414
 415         if (file) {
 416                 if (!trace_probe_get_file_link(tp, file))
 417                         return -ENOENT;
 418                 if (!trace_probe_has_single_file(tp))
 419                         goto out;
 420                 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
 421         } else
 422                 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
 423
 424         if (!trace_probe_is_enabled(tp))
 425                 __disable_trace_kprobe(tp);
 426
 427  out:
 428         if (file)
 429                 /*
 430                  * Synchronization is done in below function. For perf event,
 431                  * file == NULL and perf_trace_event_unreg() calls
 432                  * tracepoint_synchronize_unregister() to ensure synchronize
 433                  * event. We don't need to care about it.
 434                  */
 435                 trace_probe_remove_file(tp, file);
 436
 437         return 0;
 438 }
 439
 440 #if defined(CONFIG_DYNAMIC_FTRACE) && \
 441         !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
 442 static bool __within_notrace_func(unsigned long addr)
 443 {
 444         unsigned long offset, size;
 445
 446         if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
 447                 return false;
 448
 449         /* Get the entry address of the target function */
 450         addr -= offset;
 451
 452         /*
 453          * Since ftrace_location_range() does inclusive range check, we need
 454          * to subtract 1 byte from the end address.
 455          */
 456         return !ftrace_location_range(addr, addr + size - 1);
 457 }
 458
 459 static bool within_notrace_func(struct trace_kprobe *tk)
 460 {
 461         unsigned long addr = trace_kprobe_address(tk);
 462         char symname[KSYM_NAME_LEN], *p;
 463
 464         if (!__within_notrace_func(addr))
 465                 return false;
 466
 467         /* Check if the address is on a suffixed-symbol */
 468         if (!lookup_symbol_name(addr, symname)) {
 469                 p = strchr(symname, '.');
 470                 if (!p)
 471                         return true;
 472                 *p = '\0';
 473                 addr = (unsigned long)kprobe_lookup_name(symname, 0);
 474                 if (addr)
 475                         return __within_notrace_func(addr);
 476         }
 477
 478         return true;
 479 }
 480 #else
 481 #define within_notrace_func(tk) (false)
 482 #endif
 483
 484 /* Internal register function - just handle k*probes and flags */
 485 static int __register_trace_kprobe(struct trace_kprobe *tk)
 486 {
 487         int i, ret;
 488
 489         ret = security_locked_down(LOCKDOWN_KPROBES);
 490         if (ret)
 491                 return ret;
 492
 493         if (trace_kprobe_is_registered(tk))
 494                 return -EINVAL;
 495
 496         if (within_notrace_func(tk)) {
 497                 pr_warn("Could not probe notrace function %ps\n",
 498                         (void *)trace_kprobe_address(tk));
 499                 return -EINVAL;
 500         }
 501
 502         for (i = 0; i < tk->tp.nr_args; i++) {
 503                 ret = traceprobe_update_arg(&tk->tp.args[i]);
 504                 if (ret)
 505                         return ret;
 506         }
 507
 508         /* Set/clear disabled flag according to tp->flag */
 509         if (trace_probe_is_enabled(&tk->tp))
 510                 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
 511         else
 512                 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 513
 514         if (trace_kprobe_is_return(tk))
 515                 ret = register_kretprobe(&tk->rp);
 516         else
 517                 ret = register_kprobe(&tk->rp.kp);
 518
 519         return ret;
 520 }
 521
 522 /* Internal unregister function - just handle k*probes and flags */
 523 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 524 {
 525         if (trace_kprobe_is_registered(tk)) {
 526                 if (trace_kprobe_is_return(tk))
 527                         unregister_kretprobe(&tk->rp);
 528                 else
 529                         unregister_kprobe(&tk->rp.kp);
 530                 /* Cleanup kprobe for reuse and mark it unregistered */
 531                 INIT_HLIST_NODE(&tk->rp.kp.hlist);
 532                 INIT_LIST_HEAD(&tk->rp.kp.list);
 533                 if (tk->rp.kp.symbol_name)
 534                         tk->rp.kp.addr = NULL;
 535         }
 536 }
 537
 538 /* Unregister a trace_probe and probe_event */
 539 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 540 {
 541         /* If other probes are on the event, just unregister kprobe */
 542         if (trace_probe_has_sibling(&tk->tp))
 543                 goto unreg;
 544
 545         /* Enabled event can not be unregistered */
 546         if (trace_probe_is_enabled(&tk->tp))
 547                 return -EBUSY;
 548
 549         /* If there's a reference to the dynamic event */
 550         if (trace_event_dyn_busy(trace_probe_event_call(&tk->tp)))
 551                 return -EBUSY;
 552
 553         /* Will fail if probe is being used by ftrace or perf */
 554         if (unregister_kprobe_event(tk))
 555                 return -EBUSY;
 556
 557 unreg:
 558         __unregister_trace_kprobe(tk);
 559         dyn_event_remove(&tk->devent);
 560         trace_probe_unlink(&tk->tp);
 561
 562         return 0;
 563 }
 564
 565 static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
 566                                          struct trace_kprobe *comp)
 567 {
 568         struct trace_probe_event *tpe = orig->tp.event;
 569         int i;
 570
 571         list_for_each_entry(orig, &tpe->probes, tp.list) {
 572                 if (strcmp(trace_kprobe_symbol(orig),
 573                            trace_kprobe_symbol(comp)) ||
 574                     trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
 575                         continue;
 576
 577                 /*
 578                  * trace_probe_compare_arg_type() ensured that nr_args and
 579                  * each argument name and type are same. Let's compare comm.
 580                  */
 581                 for (i = 0; i < orig->tp.nr_args; i++) {
 582                         if (strcmp(orig->tp.args[i].comm,
 583                                    comp->tp.args[i].comm))
 584                                 break;
 585                 }
 586
 587                 if (i == orig->tp.nr_args)
 588                         return true;
 589         }
 590
 591         return false;
 592 }
 593
 594 static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
 595 {
 596         int ret;
 597
 598         ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
 599         if (ret) {
 600                 /* Note that argument starts index = 2 */
 601                 trace_probe_log_set_index(ret + 1);
 602                 trace_probe_log_err(0, DIFF_ARG_TYPE);
 603                 return -EEXIST;
 604         }
 605         if (trace_kprobe_has_same_kprobe(to, tk)) {
 606                 trace_probe_log_set_index(0);
 607                 trace_probe_log_err(0, SAME_PROBE);
 608                 return -EEXIST;
 609         }
 610
 611         /* Append to existing event */
 612         ret = trace_probe_append(&tk->tp, &to->tp);
 613         if (ret)
 614                 return ret;
 615
 616         /* Register k*probe */
 617         ret = __register_trace_kprobe(tk);
 618         if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
 619                 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 620                 ret = 0;
 621         }
 622
 623         if (ret)
 624                 trace_probe_unlink(&tk->tp);
 625         else
 626                 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp));
 627
 628         return ret;
 629 }
 630
 631 /* Register a trace_probe and probe_event */
 632 static int register_trace_kprobe(struct trace_kprobe *tk)
 633 {
 634         struct trace_kprobe *old_tk;
 635         int ret;
 636
 637         mutex_lock(&event_mutex);
 638
 639         old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
 640                                    trace_probe_group_name(&tk->tp));
 641         if (old_tk) {
 642                 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
 643                         trace_probe_log_set_index(0);
 644                         trace_probe_log_err(0, DIFF_PROBE_TYPE);
 645                         ret = -EEXIST;
 646                 } else {
 647                         ret = append_trace_kprobe(tk, old_tk);
 648                 }
 649                 goto end;
 650         }
 651
 652         /* Register new event */
 653         ret = register_kprobe_event(tk);
 654         if (ret) {
 655                 if (ret == -EEXIST) {
 656                         trace_probe_log_set_index(0);
 657                         trace_probe_log_err(0, EVENT_EXIST);
 658                 } else
 659                         pr_warn("Failed to register probe event(%d)\n", ret);
 660                 goto end;
 661         }
 662
 663         /* Register k*probe */
 664         ret = __register_trace_kprobe(tk);
 665         if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
 666                 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 667                 ret = 0;
 668         }
 669
 670         if (ret < 0)
 671                 unregister_kprobe_event(tk);
 672         else
 673                 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp));
 674
 675 end:
 676         mutex_unlock(&event_mutex);
 677         return ret;
 678 }
 679
 680 #ifdef CONFIG_MODULES
 681 /* Module notifier call back, checking event on the module */
 682 static int trace_kprobe_module_callback(struct notifier_block *nb,
 683                                        unsigned long val, void *data)
 684 {
 685         struct module *mod = data;
 686         struct dyn_event *pos;
 687         struct trace_kprobe *tk;
 688         int ret;
 689
 690         if (val != MODULE_STATE_COMING)
 691                 return NOTIFY_DONE;
 692
 693         /* Update probes on coming module */
 694         mutex_lock(&event_mutex);
 695         for_each_trace_kprobe(tk, pos) {
 696                 if (trace_kprobe_within_module(tk, mod)) {
 697                         /* Don't need to check busy - this should have gone. */
 698                         __unregister_trace_kprobe(tk);
 699                         ret = __register_trace_kprobe(tk);
 700                         if (ret)
 701                                 pr_warn("Failed to re-register probe %s on %s: %d\n",
 702                                         trace_probe_name(&tk->tp),
 703                                         module_name(mod), ret);
 704                 }
 705         }
 706         mutex_unlock(&event_mutex);
 707
 708         return NOTIFY_DONE;
 709 }
 710
 711 static struct notifier_block trace_kprobe_module_nb = {
 712         .notifier_call = trace_kprobe_module_callback,
 713         .priority = 1   /* Invoked after kprobe module callback */
 714 };
 715 static int trace_kprobe_register_module_notifier(void)
 716 {
 717         return register_module_notifier(&trace_kprobe_module_nb);
 718 }
 719 #else
 720 static int trace_kprobe_register_module_notifier(void)
 721 {
 722         return 0;
 723 }
 724 #endif /* CONFIG_MODULES */
 725
 726 static int count_symbols(void *data, unsigned long unused)
 727 {
 728         unsigned int *count = data;
 729
 730         (*count)++;
 731
 732         return 0;
 733 }
 734
 735 struct sym_count_ctx {
 736         unsigned int count;
 737         const char *name;
 738 };
 739
 740 static int count_mod_symbols(void *data, const char *name, unsigned long unused)
 741 {
 742         struct sym_count_ctx *ctx = data;
 743
 744         if (strcmp(name, ctx->name) == 0)
 745                 ctx->count++;
 746
 747         return 0;
 748 }
 749
 750 static unsigned int number_of_same_symbols(char *func_name)
 751 {
 752         struct sym_count_ctx ctx = { .count = 0, .name = func_name };
 753
 754         kallsyms_on_each_match_symbol(count_symbols, func_name, &ctx.count);
 755
 756         module_kallsyms_on_each_symbol(NULL, count_mod_symbols, &ctx);
 757
 758         return ctx.count;
 759 }
 760
 761 static int trace_kprobe_entry_handler(struct kretprobe_instance *ri,
 762                                       struct pt_regs *regs);
 763
 764 static int __trace_kprobe_create(int argc, const char *argv[])
 765 {
 766         /*
 767          * Argument syntax:
 768          *  - Add kprobe:
 769          *      p[:[GRP/][EVENT]] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 770          *  - Add kretprobe:
 771          *      r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]KSYM[+0] [FETCHARGS]
 772          *    Or
 773          *      p[:[GRP/][EVENT]] [MOD:]KSYM[+0]%return [FETCHARGS]
 774          *
 775          * Fetch args:
 776          *  $retval     : fetch return value
 777          *  $stack      : fetch stack address
 778          *  $stackN     : fetch Nth of stack (N:0-)
 779          *  $comm       : fetch current task comm
 780          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 781          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 782          *  %REG        : fetch register REG
 783          * Dereferencing memory fetch:
 784          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 785          * Alias name of args:
 786          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 787          * Type of args:
 788          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 789          */
 790         struct trace_kprobe *tk = NULL;
 791         int i, len, new_argc = 0, ret = 0;
 792         bool is_return = false;
 793         char *symbol = NULL, *tmp = NULL;
 794         const char **new_argv = NULL;
 795         const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
 796         enum probe_print_type ptype;
 797         int maxactive = 0;
 798         long offset = 0;
 799         void *addr = NULL;
 800         char buf[MAX_EVENT_NAME_LEN];
 801         char gbuf[MAX_EVENT_NAME_LEN];
 802         char abuf[MAX_BTF_ARGS_LEN];
 803         char *dbuf = NULL;
 804         struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL };
 805
 806         switch (argv[0][0]) {
 807         case 'r':
 808                 is_return = true;
 809                 break;
 810         case 'p':
 811                 break;
 812         default:
 813                 return -ECANCELED;
 814         }
 815         if (argc < 2)
 816                 return -ECANCELED;
 817
 818         trace_probe_log_init("trace_kprobe", argc, argv);
 819
 820         event = strchr(&argv[0][1], ':');
 821         if (event)
 822                 event++;
 823
 824         if (isdigit(argv[0][1])) {
 825                 if (!is_return) {
 826                         trace_probe_log_err(1, BAD_MAXACT_TYPE);
 827                         goto parse_error;
 828                 }
 829                 if (event)
 830                         len = event - &argv[0][1] - 1;
 831                 else
 832                         len = strlen(&argv[0][1]);
 833                 if (len > MAX_EVENT_NAME_LEN - 1) {
 834                         trace_probe_log_err(1, BAD_MAXACT);
 835                         goto parse_error;
 836                 }
 837                 memcpy(buf, &argv[0][1], len);
 838                 buf[len] = '\0';
 839                 ret = kstrtouint(buf, 0, &maxactive);
 840                 if (ret || !maxactive) {
 841                         trace_probe_log_err(1, BAD_MAXACT);
 842                         goto parse_error;
 843                 }
 844                 /* kretprobes instances are iterated over via a list. The
 845                  * maximum should stay reasonable.
 846                  */
 847                 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
 848                         trace_probe_log_err(1, MAXACT_TOO_BIG);
 849                         goto parse_error;
 850                 }
 851         }
 852
 853         /* try to parse an address. if that fails, try to read the
 854          * input as a symbol. */
 855         if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
 856                 trace_probe_log_set_index(1);
 857                 /* Check whether uprobe event specified */
 858                 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
 859                         ret = -ECANCELED;
 860                         goto error;
 861                 }
 862                 /* a symbol specified */
 863                 symbol = kstrdup(argv[1], GFP_KERNEL);
 864                 if (!symbol)
 865                         return -ENOMEM;
 866
 867                 tmp = strchr(symbol, '%');
 868                 if (tmp) {
 869                         if (!strcmp(tmp, "%return")) {
 870                                 *tmp = '\0';
 871                                 is_return = true;
 872                         } else {
 873                                 trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
 874                                 goto parse_error;
 875                         }
 876                 }
 877
 878                 /* TODO: support .init module functions */
 879                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 880                 if (ret || offset < 0 || offset > UINT_MAX) {
 881                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 882                         goto parse_error;
 883                 }
 884                 if (is_return)
 885                         ctx.flags |= TPARG_FL_RETURN;
 886                 ret = kprobe_on_func_entry(NULL, symbol, offset);
 887                 if (ret == 0 && !is_return)
 888                         ctx.flags |= TPARG_FL_FENTRY;
 889                 /* Defer the ENOENT case until register kprobe */
 890                 if (ret == -EINVAL && is_return) {
 891                         trace_probe_log_err(0, BAD_RETPROBE);
 892                         goto parse_error;
 893                 }
 894         }
 895
 896         if (symbol && !strchr(symbol, ':')) {
 897                 unsigned int count;
 898
 899                 count = number_of_same_symbols(symbol);
 900                 if (count > 1) {
 901                         /*
 902                          * Users should use ADDR to remove the ambiguity of
 903                          * using KSYM only.
 904                          */
 905                         trace_probe_log_err(0, NON_UNIQ_SYMBOL);
 906                         ret = -EADDRNOTAVAIL;
 907
 908                         goto error;
 909                 } else if (count == 0) {
 910                         /*
 911                          * We can return ENOENT earlier than when register the
 912                          * kprobe.
 913                          */
 914                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 915                         ret = -ENOENT;
 916
 917                         goto error;
 918                 }
 919         }
 920
 921         trace_probe_log_set_index(0);
 922         if (event) {
 923                 ret = traceprobe_parse_event_name(&event, &group, gbuf,
 924                                                   event - argv[0]);
 925                 if (ret)
 926                         goto parse_error;
 927         }
 928
 929         if (!event) {
 930                 /* Make a new event name */
 931                 if (symbol)
 932                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 933                                  is_return ? 'r' : 'p', symbol, offset);
 934                 else
 935                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 936                                  is_return ? 'r' : 'p', addr);
 937                 sanitize_event_name(buf);
 938                 event = buf;
 939         }
 940
 941         argc -= 2; argv += 2;
 942         ctx.funcname = symbol;
 943         new_argv = traceprobe_expand_meta_args(argc, argv, &new_argc,
 944                                                abuf, MAX_BTF_ARGS_LEN, &ctx);
 945         if (IS_ERR(new_argv)) {
 946                 ret = PTR_ERR(new_argv);
 947                 new_argv = NULL;
 948                 goto out;
 949         }
 950         if (new_argv) {
 951                 argc = new_argc;
 952                 argv = new_argv;
 953         }
 954
 955         ret = traceprobe_expand_dentry_args(argc, argv, &dbuf);
 956         if (ret)
 957                 goto out;
 958
 959         /* setup a probe */
 960         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
 961                                 argc, is_return);
 962         if (IS_ERR(tk)) {
 963                 ret = PTR_ERR(tk);
 964                 /* This must return -ENOMEM, else there is a bug */
 965                 WARN_ON_ONCE(ret != -ENOMEM);
 966                 goto out;       /* We know tk is not allocated */
 967         }
 968
 969         /* parse arguments */
 970         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 971                 trace_probe_log_set_index(i + 2);
 972                 ctx.offset = 0;
 973                 ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], &ctx);
 974                 if (ret)
 975                         goto error;     /* This can be -ENOMEM */
 976         }
 977         /* entry handler for kretprobe */
 978         if (is_return && tk->tp.entry_arg) {
 979                 tk->rp.entry_handler = trace_kprobe_entry_handler;
 980                 tk->rp.data_size = traceprobe_get_entry_data_size(&tk->tp);
 981         }
 982
 983         ptype = is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
 984         ret = traceprobe_set_print_fmt(&tk->tp, ptype);
 985         if (ret < 0)
 986                 goto error;
 987
 988         ret = register_trace_kprobe(tk);
 989         if (ret) {
 990                 trace_probe_log_set_index(1);
 991                 if (ret == -EILSEQ)
 992                         trace_probe_log_err(0, BAD_INSN_BNDRY);
 993                 else if (ret == -ENOENT)
 994                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 995                 else if (ret != -ENOMEM && ret != -EEXIST)
 996                         trace_probe_log_err(0, FAIL_REG_PROBE);
 997                 goto error;
 998         }
 999
1000 out:
1001         traceprobe_finish_parse(&ctx);
1002         trace_probe_log_clear();
1003         kfree(new_argv);
1004         kfree(symbol);
1005         kfree(dbuf);
1006         return ret;
1007
1008 parse_error:
1009         ret = -EINVAL;
1010 error:
1011         free_trace_kprobe(tk);
1012         goto out;
1013 }
1014
1015 static int trace_kprobe_create(const char *raw_command)
1016 {
1017         return trace_probe_create(raw_command, __trace_kprobe_create);
1018 }
1019
1020 static int create_or_delete_trace_kprobe(const char *raw_command)
1021 {
1022         int ret;
1023
1024         if (raw_command[0] == '-')
1025                 return dyn_event_release(raw_command, &trace_kprobe_ops);
1026
1027         ret = trace_kprobe_create(raw_command);
1028         return ret == -ECANCELED ? -EINVAL : ret;
1029 }
1030
1031 static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
1032 {
1033         return create_or_delete_trace_kprobe(cmd->seq.buffer);
1034 }
1035
1036 /**
1037  * kprobe_event_cmd_init - Initialize a kprobe event command object
1038  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1039  * @buf: A pointer to the buffer used to build the command
1040  * @maxlen: The length of the buffer passed in @buf
1041  *
1042  * Initialize a synthetic event command object.  Use this before
1043  * calling any of the other kprobe_event functions.
1044  */
1045 void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1046 {
1047         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
1048                           trace_kprobe_run_command);
1049 }
1050 EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
1051
1052 /**
1053  * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
1054  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1055  * @kretprobe: Is this a return probe?
1056  * @name: The name of the kprobe event
1057  * @loc: The location of the kprobe event
1058  * @...: Variable number of arg (pairs), one pair for each field
1059  *
1060  * NOTE: Users normally won't want to call this function directly, but
1061  * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
1062  * adds a NULL to the end of the arg list.  If this function is used
1063  * directly, make sure the last arg in the variable arg list is NULL.
1064  *
1065  * Generate a kprobe event command to be executed by
1066  * kprobe_event_gen_cmd_end().  This function can be used to generate the
1067  * complete command or only the first part of it; in the latter case,
1068  * kprobe_event_add_fields() can be used to add more fields following this.
1069  *
1070  * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
1071  * returns -EINVAL if @loc == NULL.
1072  *
1073  * Return: 0 if successful, error otherwise.
1074  */
1075 int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
1076                                  const char *name, const char *loc, ...)
1077 {
1078         char buf[MAX_EVENT_NAME_LEN];
1079         struct dynevent_arg arg;
1080         va_list args;
1081         int ret;
1082
1083         if (cmd->type != DYNEVENT_TYPE_KPROBE)
1084                 return -EINVAL;
1085
1086         if (!loc)
1087                 return -EINVAL;
1088
1089         if (kretprobe)
1090                 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
1091         else
1092                 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
1093
1094         ret = dynevent_str_add(cmd, buf);
1095         if (ret)
1096                 return ret;
1097
1098         dynevent_arg_init(&arg, 0);
1099         arg.str = loc;
1100         ret = dynevent_arg_add(cmd, &arg, NULL);
1101         if (ret)
1102                 return ret;
1103
1104         va_start(args, loc);
1105         for (;;) {
1106                 const char *field;
1107
1108                 field = va_arg(args, const char *);
1109                 if (!field)
1110                         break;
1111
1112                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1113                         ret = -EINVAL;
1114                         break;
1115                 }
1116
1117                 arg.str = field;
1118                 ret = dynevent_arg_add(cmd, &arg, NULL);
1119                 if (ret)
1120                         break;
1121         }
1122         va_end(args);
1123
1124         return ret;
1125 }
1126 EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
1127
1128 /**
1129  * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
1130  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1131  * @...: Variable number of arg (pairs), one pair for each field
1132  *
1133  * NOTE: Users normally won't want to call this function directly, but
1134  * rather use the kprobe_event_add_fields() wrapper, which
1135  * automatically adds a NULL to the end of the arg list.  If this
1136  * function is used directly, make sure the last arg in the variable
1137  * arg list is NULL.
1138  *
1139  * Add probe fields to an existing kprobe command using a variable
1140  * list of args.  Fields are added in the same order they're listed.
1141  *
1142  * Return: 0 if successful, error otherwise.
1143  */
1144 int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
1145 {
1146         struct dynevent_arg arg;
1147         va_list args;
1148         int ret = 0;
1149
1150         if (cmd->type != DYNEVENT_TYPE_KPROBE)
1151                 return -EINVAL;
1152
1153         dynevent_arg_init(&arg, 0);
1154
1155         va_start(args, cmd);
1156         for (;;) {
1157                 const char *field;
1158
1159                 field = va_arg(args, const char *);
1160                 if (!field)
1161                         break;
1162
1163                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1164                         ret = -EINVAL;
1165                         break;
1166                 }
1167
1168                 arg.str = field;
1169                 ret = dynevent_arg_add(cmd, &arg, NULL);
1170                 if (ret)
1171                         break;
1172         }
1173         va_end(args);
1174
1175         return ret;
1176 }
1177 EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
1178
1179 /**
1180  * kprobe_event_delete - Delete a kprobe event
1181  * @name: The name of the kprobe event to delete
1182  *
1183  * Delete a kprobe event with the give @name from kernel code rather
1184  * than directly from the command line.
1185  *
1186  * Return: 0 if successful, error otherwise.
1187  */
1188 int kprobe_event_delete(const char *name)
1189 {
1190         char buf[MAX_EVENT_NAME_LEN];
1191
1192         snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
1193
1194         return create_or_delete_trace_kprobe(buf);
1195 }
1196 EXPORT_SYMBOL_GPL(kprobe_event_delete);
1197
1198 static int trace_kprobe_release(struct dyn_event *ev)
1199 {
1200         struct trace_kprobe *tk = to_trace_kprobe(ev);
1201         int ret = unregister_trace_kprobe(tk);
1202
1203         if (!ret)
1204                 free_trace_kprobe(tk);
1205         return ret;
1206 }
1207
1208 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
1209 {
1210         struct trace_kprobe *tk = to_trace_kprobe(ev);
1211         int i;
1212
1213         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
1214         if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
1215                 seq_printf(m, "%d", tk->rp.maxactive);
1216         seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
1217                                 trace_probe_name(&tk->tp));
1218
1219         if (!tk->symbol)
1220                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
1221         else if (tk->rp.kp.offset)
1222                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
1223                            tk->rp.kp.offset);
1224         else
1225                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
1226
1227         for (i = 0; i < tk->tp.nr_args; i++)
1228                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
1229         seq_putc(m, '\n');
1230
1231         return 0;
1232 }
1233
1234 static int probes_seq_show(struct seq_file *m, void *v)
1235 {
1236         struct dyn_event *ev = v;
1237
1238         if (!is_trace_kprobe(ev))
1239                 return 0;
1240
1241         return trace_kprobe_show(m, ev);
1242 }
1243
1244 static const struct seq_operations probes_seq_op = {
1245         .start  = dyn_event_seq_start,
1246         .next   = dyn_event_seq_next,
1247         .stop   = dyn_event_seq_stop,
1248         .show   = probes_seq_show
1249 };
1250
1251 static int probes_open(struct inode *inode, struct file *file)
1252 {
1253         int ret;
1254
1255         ret = security_locked_down(LOCKDOWN_TRACEFS);
1256         if (ret)
1257                 return ret;
1258
1259         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1260                 ret = dyn_events_release_all(&trace_kprobe_ops);
1261                 if (ret < 0)
1262                         return ret;
1263         }
1264
1265         return seq_open(file, &probes_seq_op);
1266 }
1267
1268 static ssize_t probes_write(struct file *file, const char __user *buffer,
1269                             size_t count, loff_t *ppos)
1270 {
1271         return trace_parse_run_command(file, buffer, count, ppos,
1272                                        create_or_delete_trace_kprobe);
1273 }
1274
1275 static const struct file_operations kprobe_events_ops = {
1276         .owner          = THIS_MODULE,
1277         .open           = probes_open,
1278         .read           = seq_read,
1279         .llseek         = seq_lseek,
1280         .release        = seq_release,
1281         .write          = probes_write,
1282 };
1283
1284 static unsigned long trace_kprobe_missed(struct trace_kprobe *tk)
1285 {
1286         return trace_kprobe_is_return(tk) ?
1287                 tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed;
1288 }
1289
1290 /* Probes profiling interfaces */
1291 static int probes_profile_seq_show(struct seq_file *m, void *v)
1292 {
1293         struct dyn_event *ev = v;
1294         struct trace_kprobe *tk;
1295         unsigned long nmissed;
1296
1297         if (!is_trace_kprobe(ev))
1298                 return 0;
1299
1300         tk = to_trace_kprobe(ev);
1301         nmissed = trace_kprobe_missed(tk);
1302         seq_printf(m, "  %-44s %15lu %15lu\n",
1303                    trace_probe_name(&tk->tp),
1304                    trace_kprobe_nhit(tk),
1305                    nmissed);
1306
1307         return 0;
1308 }
1309
1310 static const struct seq_operations profile_seq_op = {
1311         .start  = dyn_event_seq_start,
1312         .next   = dyn_event_seq_next,
1313         .stop   = dyn_event_seq_stop,
1314         .show   = probes_profile_seq_show
1315 };
1316
1317 static int profile_open(struct inode *inode, struct file *file)
1318 {
1319         int ret;
1320
1321         ret = security_locked_down(LOCKDOWN_TRACEFS);
1322         if (ret)
1323                 return ret;
1324
1325         return seq_open(file, &profile_seq_op);
1326 }
1327
1328 static const struct file_operations kprobe_profile_ops = {
1329         .owner          = THIS_MODULE,
1330         .open           = profile_open,
1331         .read           = seq_read,
1332         .llseek         = seq_lseek,
1333         .release        = seq_release,
1334 };
1335
1336 /* Note that we don't verify it, since the code does not come from user space */
1337 static int
1338 process_fetch_insn(struct fetch_insn *code, void *rec, void *edata,
1339                    void *dest, void *base)
1340 {
1341         struct pt_regs *regs = rec;
1342         unsigned long val;
1343         int ret;
1344
1345 retry:
1346         /* 1st stage: get value from context */
1347         switch (code->op) {
1348         case FETCH_OP_REG:
1349                 val = regs_get_register(regs, code->param);
1350                 break;
1351         case FETCH_OP_STACK:
1352                 val = regs_get_kernel_stack_nth(regs, code->param);
1353                 break;
1354         case FETCH_OP_STACKP:
1355                 val = kernel_stack_pointer(regs);
1356                 break;
1357         case FETCH_OP_RETVAL:
1358                 val = regs_return_value(regs);
1359                 break;
1360 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1361         case FETCH_OP_ARG:
1362                 val = regs_get_kernel_argument(regs, code->param);
1363                 break;
1364         case FETCH_OP_EDATA:
1365                 val = *(unsigned long *)((unsigned long)edata + code->offset);
1366                 break;
1367 #endif
1368         case FETCH_NOP_SYMBOL:  /* Ignore a place holder */
1369                 code++;
1370                 goto retry;
1371         default:
1372                 ret = process_common_fetch_insn(code, &val);
1373                 if (ret < 0)
1374                         return ret;
1375         }
1376         code++;
1377
1378         return process_fetch_insn_bottom(code, val, dest, base);
1379 }
1380 NOKPROBE_SYMBOL(process_fetch_insn)
1381
1382 /* Kprobe handler */
1383 static nokprobe_inline void
1384 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1385                     struct trace_event_file *trace_file)
1386 {
1387         struct kprobe_trace_entry_head *entry;
1388         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1389         struct trace_event_buffer fbuffer;
1390         int dsize;
1391
1392         WARN_ON(call != trace_file->event_call);
1393
1394         if (trace_trigger_soft_disabled(trace_file))
1395                 return;
1396
1397         dsize = __get_data_size(&tk->tp, regs, NULL);
1398
1399         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1400                                            sizeof(*entry) + tk->tp.size + dsize);
1401         if (!entry)
1402                 return;
1403
1404         fbuffer.regs = regs;
1405         entry->ip = (unsigned long)tk->rp.kp.addr;
1406         store_trace_args(&entry[1], &tk->tp, regs, NULL, sizeof(*entry), dsize);
1407
1408         trace_event_buffer_commit(&fbuffer);
1409 }
1410
1411 static void
1412 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1413 {
1414         struct event_file_link *link;
1415
1416         trace_probe_for_each_link_rcu(link, &tk->tp)
1417                 __kprobe_trace_func(tk, regs, link->file);
1418 }
1419 NOKPROBE_SYMBOL(kprobe_trace_func);
1420
1421 /* Kretprobe handler */
1422
1423 static int trace_kprobe_entry_handler(struct kretprobe_instance *ri,
1424                                       struct pt_regs *regs)
1425 {
1426         struct kretprobe *rp = get_kretprobe(ri);
1427         struct trace_kprobe *tk;
1428
1429         /*
1430          * There is a small chance that get_kretprobe(ri) returns NULL when
1431          * the kretprobe is unregister on another CPU between kretprobe's
1432          * trampoline_handler and this function.
1433          */
1434         if (unlikely(!rp))
1435                 return -ENOENT;
1436
1437         tk = container_of(rp, struct trace_kprobe, rp);
1438
1439         /* store argument values into ri->data as entry data */
1440         if (tk->tp.entry_arg)
1441                 store_trace_entry_data(ri->data, &tk->tp, regs);
1442
1443         return 0;
1444 }
1445
1446
1447 static nokprobe_inline void
1448 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1449                        struct pt_regs *regs,
1450                        struct trace_event_file *trace_file)
1451 {
1452         struct kretprobe_trace_entry_head *entry;
1453         struct trace_event_buffer fbuffer;
1454         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1455         int dsize;
1456
1457         WARN_ON(call != trace_file->event_call);
1458
1459         if (trace_trigger_soft_disabled(trace_file))
1460                 return;
1461
1462         dsize = __get_data_size(&tk->tp, regs, ri->data);
1463
1464         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1465                                            sizeof(*entry) + tk->tp.size + dsize);
1466         if (!entry)
1467                 return;
1468
1469         fbuffer.regs = regs;
1470         entry->func = (unsigned long)tk->rp.kp.addr;
1471         entry->ret_ip = get_kretprobe_retaddr(ri);
1472         store_trace_args(&entry[1], &tk->tp, regs, ri->data, sizeof(*entry), dsize);
1473
1474         trace_event_buffer_commit(&fbuffer);
1475 }
1476
1477 static void
1478 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1479                      struct pt_regs *regs)
1480 {
1481         struct event_file_link *link;
1482
1483         trace_probe_for_each_link_rcu(link, &tk->tp)
1484                 __kretprobe_trace_func(tk, ri, regs, link->file);
1485 }
1486 NOKPROBE_SYMBOL(kretprobe_trace_func);
1487
1488 /* Event entry printers */
1489 static enum print_line_t
1490 print_kprobe_event(struct trace_iterator *iter, int flags,
1491                    struct trace_event *event)
1492 {
1493         struct kprobe_trace_entry_head *field;
1494         struct trace_seq *s = &iter->seq;
1495         struct trace_probe *tp;
1496
1497         field = (struct kprobe_trace_entry_head *)iter->ent;
1498         tp = trace_probe_primary_from_call(
1499                 container_of(event, struct trace_event_call, event));
1500         if (WARN_ON_ONCE(!tp))
1501                 goto out;
1502
1503         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1504
1505         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1506                 goto out;
1507
1508         trace_seq_putc(s, ')');
1509
1510         if (trace_probe_print_args(s, tp->args, tp->nr_args,
1511                              (u8 *)&field[1], field) < 0)
1512                 goto out;
1513
1514         trace_seq_putc(s, '\n');
1515  out:
1516         return trace_handle_return(s);
1517 }
1518
1519 static enum print_line_t
1520 print_kretprobe_event(struct trace_iterator *iter, int flags,
1521                       struct trace_event *event)
1522 {
1523         struct kretprobe_trace_entry_head *field;
1524         struct trace_seq *s = &iter->seq;
1525         struct trace_probe *tp;
1526
1527         field = (struct kretprobe_trace_entry_head *)iter->ent;
1528         tp = trace_probe_primary_from_call(
1529                 container_of(event, struct trace_event_call, event));
1530         if (WARN_ON_ONCE(!tp))
1531                 goto out;
1532
1533         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1534
1535         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1536                 goto out;
1537
1538         trace_seq_puts(s, " <- ");
1539
1540         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1541                 goto out;
1542
1543         trace_seq_putc(s, ')');
1544
1545         if (trace_probe_print_args(s, tp->args, tp->nr_args,
1546                              (u8 *)&field[1], field) < 0)
1547                 goto out;
1548
1549         trace_seq_putc(s, '\n');
1550
1551  out:
1552         return trace_handle_return(s);
1553 }
1554
1555
1556 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1557 {
1558         int ret;
1559         struct kprobe_trace_entry_head field;
1560         struct trace_probe *tp;
1561
1562         tp = trace_probe_primary_from_call(event_call);
1563         if (WARN_ON_ONCE(!tp))
1564                 return -ENOENT;
1565
1566         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1567
1568         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1569 }
1570
1571 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1572 {
1573         int ret;
1574         struct kretprobe_trace_entry_head field;
1575         struct trace_probe *tp;
1576
1577         tp = trace_probe_primary_from_call(event_call);
1578         if (WARN_ON_ONCE(!tp))
1579                 return -ENOENT;
1580
1581         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1582         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1583
1584         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1585 }
1586
1587 #ifdef CONFIG_PERF_EVENTS
1588
1589 /* Kprobe profile handler */
1590 static int
1591 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1592 {
1593         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1594         struct kprobe_trace_entry_head *entry;
1595         struct hlist_head *head;
1596         int size, __size, dsize;
1597         int rctx;
1598
1599         if (bpf_prog_array_valid(call)) {
1600                 unsigned long orig_ip = instruction_pointer(regs);
1601                 int ret;
1602
1603                 ret = trace_call_bpf(call, regs);
1604
1605                 /*
1606                  * We need to check and see if we modified the pc of the
1607                  * pt_regs, and if so return 1 so that we don't do the
1608                  * single stepping.
1609                  */
1610                 if (orig_ip != instruction_pointer(regs))
1611                         return 1;
1612                 if (!ret)
1613                         return 0;
1614         }
1615
1616         head = this_cpu_ptr(call->perf_events);
1617         if (hlist_empty(head))
1618                 return 0;
1619
1620         dsize = __get_data_size(&tk->tp, regs, NULL);
1621         __size = sizeof(*entry) + tk->tp.size + dsize;
1622         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1623         size -= sizeof(u32);
1624
1625         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1626         if (!entry)
1627                 return 0;
1628
1629         entry->ip = (unsigned long)tk->rp.kp.addr;
1630         memset(&entry[1], 0, dsize);
1631         store_trace_args(&entry[1], &tk->tp, regs, NULL, sizeof(*entry), dsize);
1632         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1633                               head, NULL);
1634         return 0;
1635 }
1636 NOKPROBE_SYMBOL(kprobe_perf_func);
1637
1638 /* Kretprobe profile handler */
1639 static void
1640 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1641                     struct pt_regs *regs)
1642 {
1643         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1644         struct kretprobe_trace_entry_head *entry;
1645         struct hlist_head *head;
1646         int size, __size, dsize;
1647         int rctx;
1648
1649         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1650                 return;
1651
1652         head = this_cpu_ptr(call->perf_events);
1653         if (hlist_empty(head))
1654                 return;
1655
1656         dsize = __get_data_size(&tk->tp, regs, ri->data);
1657         __size = sizeof(*entry) + tk->tp.size + dsize;
1658         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1659         size -= sizeof(u32);
1660
1661         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1662         if (!entry)
1663                 return;
1664
1665         entry->func = (unsigned long)tk->rp.kp.addr;
1666         entry->ret_ip = get_kretprobe_retaddr(ri);
1667         store_trace_args(&entry[1], &tk->tp, regs, ri->data, sizeof(*entry), dsize);
1668         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1669                               head, NULL);
1670 }
1671 NOKPROBE_SYMBOL(kretprobe_perf_func);
1672
1673 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1674                         const char **symbol, u64 *probe_offset,
1675                         u64 *probe_addr, unsigned long *missed,
1676                         bool perf_type_tracepoint)
1677 {
1678         const char *pevent = trace_event_name(event->tp_event);
1679         const char *group = event->tp_event->class->system;
1680         struct trace_kprobe *tk;
1681
1682         if (perf_type_tracepoint)
1683                 tk = find_trace_kprobe(pevent, group);
1684         else
1685                 tk = trace_kprobe_primary_from_call(event->tp_event);
1686         if (!tk)
1687                 return -EINVAL;
1688
1689         *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1690                                               : BPF_FD_TYPE_KPROBE;
1691         *probe_offset = tk->rp.kp.offset;
1692         *probe_addr = kallsyms_show_value(current_cred()) ?
1693                       (unsigned long)tk->rp.kp.addr : 0;
1694         *symbol = tk->symbol;
1695         if (missed)
1696                 *missed = trace_kprobe_missed(tk);
1697         return 0;
1698 }
1699 #endif  /* CONFIG_PERF_EVENTS */
1700
1701 /*
1702  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1703  *
1704  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1705  * lockless, but we can't race with this __init function.
1706  */
1707 static int kprobe_register(struct trace_event_call *event,
1708                            enum trace_reg type, void *data)
1709 {
1710         struct trace_event_file *file = data;
1711
1712         switch (type) {
1713         case TRACE_REG_REGISTER:
1714                 return enable_trace_kprobe(event, file);
1715         case TRACE_REG_UNREGISTER:
1716                 return disable_trace_kprobe(event, file);
1717
1718 #ifdef CONFIG_PERF_EVENTS
1719         case TRACE_REG_PERF_REGISTER:
1720                 return enable_trace_kprobe(event, NULL);
1721         case TRACE_REG_PERF_UNREGISTER:
1722                 return disable_trace_kprobe(event, NULL);
1723         case TRACE_REG_PERF_OPEN:
1724         case TRACE_REG_PERF_CLOSE:
1725         case TRACE_REG_PERF_ADD:
1726         case TRACE_REG_PERF_DEL:
1727                 return 0;
1728 #endif
1729         }
1730         return 0;
1731 }
1732
1733 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1734 {
1735         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1736         int ret = 0;
1737
1738         raw_cpu_inc(*tk->nhit);
1739
1740         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1741                 kprobe_trace_func(tk, regs);
1742 #ifdef CONFIG_PERF_EVENTS
1743         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1744                 ret = kprobe_perf_func(tk, regs);
1745 #endif
1746         return ret;
1747 }
1748 NOKPROBE_SYMBOL(kprobe_dispatcher);
1749
1750 static int
1751 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1752 {
1753         struct kretprobe *rp = get_kretprobe(ri);
1754         struct trace_kprobe *tk;
1755
1756         /*
1757          * There is a small chance that get_kretprobe(ri) returns NULL when
1758          * the kretprobe is unregister on another CPU between kretprobe's
1759          * trampoline_handler and this function.
1760          */
1761         if (unlikely(!rp))
1762                 return 0;
1763
1764         tk = container_of(rp, struct trace_kprobe, rp);
1765         raw_cpu_inc(*tk->nhit);
1766
1767         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1768                 kretprobe_trace_func(tk, ri, regs);
1769 #ifdef CONFIG_PERF_EVENTS
1770         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1771                 kretprobe_perf_func(tk, ri, regs);
1772 #endif
1773         return 0;       /* We don't tweak kernel, so just return 0 */
1774 }
1775 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1776
1777 static struct trace_event_functions kretprobe_funcs = {
1778         .trace          = print_kretprobe_event
1779 };
1780
1781 static struct trace_event_functions kprobe_funcs = {
1782         .trace          = print_kprobe_event
1783 };
1784
1785 static struct trace_event_fields kretprobe_fields_array[] = {
1786         { .type = TRACE_FUNCTION_TYPE,
1787           .define_fields = kretprobe_event_define_fields },
1788         {}
1789 };
1790
1791 static struct trace_event_fields kprobe_fields_array[] = {
1792         { .type = TRACE_FUNCTION_TYPE,
1793           .define_fields = kprobe_event_define_fields },
1794         {}
1795 };
1796
1797 static inline void init_trace_event_call(struct trace_kprobe *tk)
1798 {
1799         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1800
1801         if (trace_kprobe_is_return(tk)) {
1802                 call->event.funcs = &kretprobe_funcs;
1803                 call->class->fields_array = kretprobe_fields_array;
1804         } else {
1805                 call->event.funcs = &kprobe_funcs;
1806                 call->class->fields_array = kprobe_fields_array;
1807         }
1808
1809         call->flags = TRACE_EVENT_FL_KPROBE;
1810         call->class->reg = kprobe_register;
1811 }
1812
1813 static int register_kprobe_event(struct trace_kprobe *tk)
1814 {
1815         init_trace_event_call(tk);
1816
1817         return trace_probe_register_event_call(&tk->tp);
1818 }
1819
1820 static int unregister_kprobe_event(struct trace_kprobe *tk)
1821 {
1822         return trace_probe_unregister_event_call(&tk->tp);
1823 }
1824
1825 #ifdef CONFIG_PERF_EVENTS
1826
1827 /* create a trace_kprobe, but don't add it to global lists */
1828 struct trace_event_call *
1829 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1830                           bool is_return)
1831 {
1832         enum probe_print_type ptype;
1833         struct trace_kprobe *tk;
1834         int ret;
1835         char *event;
1836
1837         if (func) {
1838                 unsigned int count;
1839
1840                 count = number_of_same_symbols(func);
1841                 if (count > 1)
1842                         /*
1843                          * Users should use addr to remove the ambiguity of
1844                          * using func only.
1845                          */
1846                         return ERR_PTR(-EADDRNOTAVAIL);
1847                 else if (count == 0)
1848                         /*
1849                          * We can return ENOENT earlier than when register the
1850                          * kprobe.
1851                          */
1852                         return ERR_PTR(-ENOENT);
1853         }
1854
1855         /*
1856          * local trace_kprobes are not added to dyn_event, so they are never
1857          * searched in find_trace_kprobe(). Therefore, there is no concern of
1858          * duplicated name here.
1859          */
1860         event = func ? func : "DUMMY_EVENT";
1861
1862         tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1863                                 offs, 0 /* maxactive */, 0 /* nargs */,
1864                                 is_return);
1865
1866         if (IS_ERR(tk)) {
1867                 pr_info("Failed to allocate trace_probe.(%d)\n",
1868                         (int)PTR_ERR(tk));
1869                 return ERR_CAST(tk);
1870         }
1871
1872         init_trace_event_call(tk);
1873
1874         ptype = trace_kprobe_is_return(tk) ?
1875                 PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
1876         if (traceprobe_set_print_fmt(&tk->tp, ptype) < 0) {
1877                 ret = -ENOMEM;
1878                 goto error;
1879         }
1880
1881         ret = __register_trace_kprobe(tk);
1882         if (ret < 0)
1883                 goto error;
1884
1885         return trace_probe_event_call(&tk->tp);
1886 error:
1887         free_trace_kprobe(tk);
1888         return ERR_PTR(ret);
1889 }
1890
1891 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1892 {
1893         struct trace_kprobe *tk;
1894
1895         tk = trace_kprobe_primary_from_call(event_call);
1896         if (unlikely(!tk))
1897                 return;
1898
1899         if (trace_probe_is_enabled(&tk->tp)) {
1900                 WARN_ON(1);
1901                 return;
1902         }
1903
1904         __unregister_trace_kprobe(tk);
1905
1906         free_trace_kprobe(tk);
1907 }
1908 #endif /* CONFIG_PERF_EVENTS */
1909
1910 static __init void enable_boot_kprobe_events(void)
1911 {
1912         struct trace_array *tr = top_trace_array();
1913         struct trace_event_file *file;
1914         struct trace_kprobe *tk;
1915         struct dyn_event *pos;
1916
1917         mutex_lock(&event_mutex);
1918         for_each_trace_kprobe(tk, pos) {
1919                 list_for_each_entry(file, &tr->events, list)
1920                         if (file->event_call == trace_probe_event_call(&tk->tp))
1921                                 trace_event_enable_disable(file, 1, 0);
1922         }
1923         mutex_unlock(&event_mutex);
1924 }
1925
1926 static __init void setup_boot_kprobe_events(void)
1927 {
1928         char *p, *cmd = kprobe_boot_events_buf;
1929         int ret;
1930
1931         strreplace(kprobe_boot_events_buf, ',', ' ');
1932
1933         while (cmd && *cmd != '\0') {
1934                 p = strchr(cmd, ';');
1935                 if (p)
1936                         *p++ = '\0';
1937
1938                 ret = create_or_delete_trace_kprobe(cmd);
1939                 if (ret)
1940                         pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1941
1942                 cmd = p;
1943         }
1944
1945         enable_boot_kprobe_events();
1946 }
1947
1948 /*
1949  * Register dynevent at core_initcall. This allows kernel to setup kprobe
1950  * events in postcore_initcall without tracefs.
1951  */
1952 static __init int init_kprobe_trace_early(void)
1953 {
1954         int ret;
1955
1956         ret = dyn_event_register(&trace_kprobe_ops);
1957         if (ret)
1958                 return ret;
1959
1960         if (trace_kprobe_register_module_notifier())
1961                 return -EINVAL;
1962
1963         return 0;
1964 }
1965 core_initcall(init_kprobe_trace_early);
1966
1967 /* Make a tracefs interface for controlling probe points */
1968 static __init int init_kprobe_trace(void)
1969 {
1970         int ret;
1971
1972         ret = tracing_init_dentry();
1973         if (ret)
1974                 return 0;
1975
1976         /* Event list interface */
1977         trace_create_file("kprobe_events", TRACE_MODE_WRITE,
1978                           NULL, NULL, &kprobe_events_ops);
1979
1980         /* Profile interface */
1981         trace_create_file("kprobe_profile", TRACE_MODE_READ,
1982                           NULL, NULL, &kprobe_profile_ops);
1983
1984         setup_boot_kprobe_events();
1985
1986         return 0;
1987 }
1988 fs_initcall(init_kprobe_trace);
1989
1990
1991 #ifdef CONFIG_FTRACE_STARTUP_TEST
1992 static __init struct trace_event_file *
1993 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1994 {
1995         struct trace_event_file *file;
1996
1997         list_for_each_entry(file, &tr->events, list)
1998                 if (file->event_call == trace_probe_event_call(&tk->tp))
1999                         return file;
2000
2001         return NULL;
2002 }
2003
2004 /*
2005  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
2006  * stage, we can do this lockless.
2007  */
2008 static __init int kprobe_trace_self_tests_init(void)
2009 {
2010         int ret, warn = 0;
2011         int (*target)(int, int, int, int, int, int);
2012         struct trace_kprobe *tk;
2013         struct trace_event_file *file;
2014
2015         if (tracing_is_disabled())
2016                 return -ENODEV;
2017
2018         if (tracing_selftest_disabled)
2019                 return 0;
2020
2021         target = kprobe_trace_selftest_target;
2022
2023         pr_info("Testing kprobe tracing: ");
2024
2025         ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
2026         if (WARN_ON_ONCE(ret)) {
2027                 pr_warn("error on probing function entry.\n");
2028                 warn++;
2029         } else {
2030                 /* Enable trace point */
2031                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2032                 if (WARN_ON_ONCE(tk == NULL)) {
2033                         pr_warn("error on getting new probe.\n");
2034                         warn++;
2035                 } else {
2036                         file = find_trace_probe_file(tk, top_trace_array());
2037                         if (WARN_ON_ONCE(file == NULL)) {
2038                                 pr_warn("error on getting probe file.\n");
2039                                 warn++;
2040                         } else
2041                                 enable_trace_kprobe(
2042                                         trace_probe_event_call(&tk->tp), file);
2043                 }
2044         }
2045
2046         ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
2047         if (WARN_ON_ONCE(ret)) {
2048                 pr_warn("error on probing function return.\n");
2049                 warn++;
2050         } else {
2051                 /* Enable trace point */
2052                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2053                 if (WARN_ON_ONCE(tk == NULL)) {
2054                         pr_warn("error on getting 2nd new probe.\n");
2055                         warn++;
2056                 } else {
2057                         file = find_trace_probe_file(tk, top_trace_array());
2058                         if (WARN_ON_ONCE(file == NULL)) {
2059                                 pr_warn("error on getting probe file.\n");
2060                                 warn++;
2061                         } else
2062                                 enable_trace_kprobe(
2063                                         trace_probe_event_call(&tk->tp), file);
2064                 }
2065         }
2066
2067         if (warn)
2068                 goto end;
2069
2070         ret = target(1, 2, 3, 4, 5, 6);
2071
2072         /*
2073          * Not expecting an error here, the check is only to prevent the
2074          * optimizer from removing the call to target() as otherwise there
2075          * are no side-effects and the call is never performed.
2076          */
2077         if (ret != 21)
2078                 warn++;
2079
2080         /* Disable trace points before removing it */
2081         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2082         if (WARN_ON_ONCE(tk == NULL)) {
2083                 pr_warn("error on getting test probe.\n");
2084                 warn++;
2085         } else {
2086                 if (trace_kprobe_nhit(tk) != 1) {
2087                         pr_warn("incorrect number of testprobe hits\n");
2088                         warn++;
2089                 }
2090
2091                 file = find_trace_probe_file(tk, top_trace_array());
2092                 if (WARN_ON_ONCE(file == NULL)) {
2093                         pr_warn("error on getting probe file.\n");
2094                         warn++;
2095                 } else
2096                         disable_trace_kprobe(
2097                                 trace_probe_event_call(&tk->tp), file);
2098         }
2099
2100         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2101         if (WARN_ON_ONCE(tk == NULL)) {
2102                 pr_warn("error on getting 2nd test probe.\n");
2103                 warn++;
2104         } else {
2105                 if (trace_kprobe_nhit(tk) != 1) {
2106                         pr_warn("incorrect number of testprobe2 hits\n");
2107                         warn++;
2108                 }
2109
2110                 file = find_trace_probe_file(tk, top_trace_array());
2111                 if (WARN_ON_ONCE(file == NULL)) {
2112                         pr_warn("error on getting probe file.\n");
2113                         warn++;
2114                 } else
2115                         disable_trace_kprobe(
2116                                 trace_probe_event_call(&tk->tp), file);
2117         }
2118
2119         ret = create_or_delete_trace_kprobe("-:testprobe");
2120         if (WARN_ON_ONCE(ret)) {
2121                 pr_warn("error on deleting a probe.\n");
2122                 warn++;
2123         }
2124
2125         ret = create_or_delete_trace_kprobe("-:testprobe2");
2126         if (WARN_ON_ONCE(ret)) {
2127                 pr_warn("error on deleting a probe.\n");
2128                 warn++;
2129         }
2130
2131 end:
2132         ret = dyn_events_release_all(&trace_kprobe_ops);
2133         if (WARN_ON_ONCE(ret)) {
2134                 pr_warn("error on cleaning up probes.\n");
2135                 warn++;
2136         }
2137         /*
2138          * Wait for the optimizer work to finish. Otherwise it might fiddle
2139          * with probes in already freed __init text.
2140          */
2141         wait_for_kprobe_optimizer();
2142         if (warn)
2143                 pr_cont("NG: Some tests are failed. Please check them.\n");
2144         else
2145                 pr_cont("OK\n");
2146         return 0;
2147 }
2148
2149 late_initcall(kprobe_trace_self_tests_init);
2150
2151 #endif