kernel/trace/trace_kprobe.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Kprobes-based tracing events
   4  *
   5  * Created by Masami Hiramatsu <[email protected]>
   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 static int validate_module_probe_symbol(const char *modname, const char *symbol);
 682
 683 static int register_module_trace_kprobe(struct module *mod, struct trace_kprobe *tk)
 684 {
 685         const char *p;
 686         int ret = 0;
 687
 688         p = strchr(trace_kprobe_symbol(tk), ':');
 689         if (p)
 690                 ret = validate_module_probe_symbol(module_name(mod), p + 1);
 691         if (!ret)
 692                 ret = __register_trace_kprobe(tk);
 693         return ret;
 694 }
 695
 696 /* Module notifier call back, checking event on the module */
 697 static int trace_kprobe_module_callback(struct notifier_block *nb,
 698                                        unsigned long val, void *data)
 699 {
 700         struct module *mod = data;
 701         struct dyn_event *pos;
 702         struct trace_kprobe *tk;
 703         int ret;
 704
 705         if (val != MODULE_STATE_COMING)
 706                 return NOTIFY_DONE;
 707
 708         /* Update probes on coming module */
 709         mutex_lock(&event_mutex);
 710         for_each_trace_kprobe(tk, pos) {
 711                 if (trace_kprobe_within_module(tk, mod)) {
 712                         /* Don't need to check busy - this should have gone. */
 713                         __unregister_trace_kprobe(tk);
 714                         ret = register_module_trace_kprobe(mod, tk);
 715                         if (ret)
 716                                 pr_warn("Failed to re-register probe %s on %s: %d\n",
 717                                         trace_probe_name(&tk->tp),
 718                                         module_name(mod), ret);
 719                 }
 720         }
 721         mutex_unlock(&event_mutex);
 722
 723         return NOTIFY_DONE;
 724 }
 725
 726 static struct notifier_block trace_kprobe_module_nb = {
 727         .notifier_call = trace_kprobe_module_callback,
 728         .priority = 2   /* Invoked after kprobe and jump_label module callback */
 729 };
 730 static int trace_kprobe_register_module_notifier(void)
 731 {
 732         return register_module_notifier(&trace_kprobe_module_nb);
 733 }
 734 #else
 735 static int trace_kprobe_register_module_notifier(void)
 736 {
 737         return 0;
 738 }
 739 #endif /* CONFIG_MODULES */
 740
 741 static int count_symbols(void *data, unsigned long unused)
 742 {
 743         unsigned int *count = data;
 744
 745         (*count)++;
 746
 747         return 0;
 748 }
 749
 750 struct sym_count_ctx {
 751         unsigned int count;
 752         const char *name;
 753 };
 754
 755 static int count_mod_symbols(void *data, const char *name, unsigned long unused)
 756 {
 757         struct sym_count_ctx *ctx = data;
 758
 759         if (strcmp(name, ctx->name) == 0)
 760                 ctx->count++;
 761
 762         return 0;
 763 }
 764
 765 static unsigned int number_of_same_symbols(const char *mod, const char *func_name)
 766 {
 767         struct sym_count_ctx ctx = { .count = 0, .name = func_name };
 768
 769         if (!mod)
 770                 kallsyms_on_each_match_symbol(count_symbols, func_name, &ctx.count);
 771
 772         module_kallsyms_on_each_symbol(mod, count_mod_symbols, &ctx);
 773
 774         return ctx.count;
 775 }
 776
 777 static int validate_module_probe_symbol(const char *modname, const char *symbol)
 778 {
 779         unsigned int count = number_of_same_symbols(modname, symbol);
 780
 781         if (count > 1) {
 782                 /*
 783                  * Users should use ADDR to remove the ambiguity of
 784                  * using KSYM only.
 785                  */
 786                 return -EADDRNOTAVAIL;
 787         } else if (count == 0) {
 788                 /*
 789                  * We can return ENOENT earlier than when register the
 790                  * kprobe.
 791                  */
 792                 return -ENOENT;
 793         }
 794         return 0;
 795 }
 796
 797 #ifdef CONFIG_MODULES
 798 /* Return NULL if the module is not loaded or under unloading. */
 799 static struct module *try_module_get_by_name(const char *name)
 800 {
 801         struct module *mod;
 802
 803         rcu_read_lock_sched();
 804         mod = find_module(name);
 805         if (mod && !try_module_get(mod))
 806                 mod = NULL;
 807         rcu_read_unlock_sched();
 808
 809         return mod;
 810 }
 811 #else
 812 #define try_module_get_by_name(name)    (NULL)
 813 #endif
 814
 815 static int validate_probe_symbol(char *symbol)
 816 {
 817         struct module *mod = NULL;
 818         char *modname = NULL, *p;
 819         int ret = 0;
 820
 821         p = strchr(symbol, ':');
 822         if (p) {
 823                 modname = symbol;
 824                 symbol = p + 1;
 825                 *p = '\0';
 826                 mod = try_module_get_by_name(modname);
 827                 if (!mod)
 828                         goto out;
 829         }
 830
 831         ret = validate_module_probe_symbol(modname, symbol);
 832 out:
 833         if (p)
 834                 *p = ':';
 835         if (mod)
 836                 module_put(mod);
 837         return ret;
 838 }
 839
 840 static int trace_kprobe_entry_handler(struct kretprobe_instance *ri,
 841                                       struct pt_regs *regs);
 842
 843 static int __trace_kprobe_create(int argc, const char *argv[])
 844 {
 845         /*
 846          * Argument syntax:
 847          *  - Add kprobe:
 848          *      p[:[GRP/][EVENT]] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 849          *  - Add kretprobe:
 850          *      r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]KSYM[+0] [FETCHARGS]
 851          *    Or
 852          *      p[:[GRP/][EVENT]] [MOD:]KSYM[+0]%return [FETCHARGS]
 853          *
 854          * Fetch args:
 855          *  $retval     : fetch return value
 856          *  $stack      : fetch stack address
 857          *  $stackN     : fetch Nth of stack (N:0-)
 858          *  $comm       : fetch current task comm
 859          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 860          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 861          *  %REG        : fetch register REG
 862          * Dereferencing memory fetch:
 863          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 864          * Alias name of args:
 865          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 866          * Type of args:
 867          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 868          */
 869         struct trace_kprobe *tk = NULL;
 870         int i, len, new_argc = 0, ret = 0;
 871         bool is_return = false;
 872         char *symbol = NULL, *tmp = NULL;
 873         const char **new_argv = NULL;
 874         const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
 875         enum probe_print_type ptype;
 876         int maxactive = 0;
 877         long offset = 0;
 878         void *addr = NULL;
 879         char buf[MAX_EVENT_NAME_LEN];
 880         char gbuf[MAX_EVENT_NAME_LEN];
 881         char abuf[MAX_BTF_ARGS_LEN];
 882         char *dbuf = NULL;
 883         struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL };
 884
 885         switch (argv[0][0]) {
 886         case 'r':
 887                 is_return = true;
 888                 break;
 889         case 'p':
 890                 break;
 891         default:
 892                 return -ECANCELED;
 893         }
 894         if (argc < 2)
 895                 return -ECANCELED;
 896
 897         trace_probe_log_init("trace_kprobe", argc, argv);
 898
 899         event = strchr(&argv[0][1], ':');
 900         if (event)
 901                 event++;
 902
 903         if (isdigit(argv[0][1])) {
 904                 if (!is_return) {
 905                         trace_probe_log_err(1, BAD_MAXACT_TYPE);
 906                         goto parse_error;
 907                 }
 908                 if (event)
 909                         len = event - &argv[0][1] - 1;
 910                 else
 911                         len = strlen(&argv[0][1]);
 912                 if (len > MAX_EVENT_NAME_LEN - 1) {
 913                         trace_probe_log_err(1, BAD_MAXACT);
 914                         goto parse_error;
 915                 }
 916                 memcpy(buf, &argv[0][1], len);
 917                 buf[len] = '\0';
 918                 ret = kstrtouint(buf, 0, &maxactive);
 919                 if (ret || !maxactive) {
 920                         trace_probe_log_err(1, BAD_MAXACT);
 921                         goto parse_error;
 922                 }
 923                 /* kretprobes instances are iterated over via a list. The
 924                  * maximum should stay reasonable.
 925                  */
 926                 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
 927                         trace_probe_log_err(1, MAXACT_TOO_BIG);
 928                         goto parse_error;
 929                 }
 930         }
 931
 932         /* try to parse an address. if that fails, try to read the
 933          * input as a symbol. */
 934         if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
 935                 trace_probe_log_set_index(1);
 936                 /* Check whether uprobe event specified */
 937                 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
 938                         ret = -ECANCELED;
 939                         goto error;
 940                 }
 941                 /* a symbol specified */
 942                 symbol = kstrdup(argv[1], GFP_KERNEL);
 943                 if (!symbol)
 944                         return -ENOMEM;
 945
 946                 tmp = strchr(symbol, '%');
 947                 if (tmp) {
 948                         if (!strcmp(tmp, "%return")) {
 949                                 *tmp = '\0';
 950                                 is_return = true;
 951                         } else {
 952                                 trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
 953                                 goto parse_error;
 954                         }
 955                 }
 956
 957                 /* TODO: support .init module functions */
 958                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 959                 if (ret || offset < 0 || offset > UINT_MAX) {
 960                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 961                         goto parse_error;
 962                 }
 963                 ret = validate_probe_symbol(symbol);
 964                 if (ret) {
 965                         if (ret == -EADDRNOTAVAIL)
 966                                 trace_probe_log_err(0, NON_UNIQ_SYMBOL);
 967                         else
 968                                 trace_probe_log_err(0, BAD_PROBE_ADDR);
 969                         goto parse_error;
 970                 }
 971                 if (is_return)
 972                         ctx.flags |= TPARG_FL_RETURN;
 973                 ret = kprobe_on_func_entry(NULL, symbol, offset);
 974                 if (ret == 0 && !is_return)
 975                         ctx.flags |= TPARG_FL_FENTRY;
 976                 /* Defer the ENOENT case until register kprobe */
 977                 if (ret == -EINVAL && is_return) {
 978                         trace_probe_log_err(0, BAD_RETPROBE);
 979                         goto parse_error;
 980                 }
 981         }
 982
 983         trace_probe_log_set_index(0);
 984         if (event) {
 985                 ret = traceprobe_parse_event_name(&event, &group, gbuf,
 986                                                   event - argv[0]);
 987                 if (ret)
 988                         goto parse_error;
 989         }
 990
 991         if (!event) {
 992                 /* Make a new event name */
 993                 if (symbol)
 994                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 995                                  is_return ? 'r' : 'p', symbol, offset);
 996                 else
 997                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 998                                  is_return ? 'r' : 'p', addr);
 999                 sanitize_event_name(buf);
1000                 event = buf;
1001         }
1002
1003         argc -= 2; argv += 2;
1004         ctx.funcname = symbol;
1005         new_argv = traceprobe_expand_meta_args(argc, argv, &new_argc,
1006                                                abuf, MAX_BTF_ARGS_LEN, &ctx);
1007         if (IS_ERR(new_argv)) {
1008                 ret = PTR_ERR(new_argv);
1009                 new_argv = NULL;
1010                 goto out;
1011         }
1012         if (new_argv) {
1013                 argc = new_argc;
1014                 argv = new_argv;
1015         }
1016         if (argc > MAX_TRACE_ARGS) {
1017                 ret = -E2BIG;
1018                 goto out;
1019         }
1020
1021         ret = traceprobe_expand_dentry_args(argc, argv, &dbuf);
1022         if (ret)
1023                 goto out;
1024
1025         /* setup a probe */
1026         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
1027                                 argc, is_return);
1028         if (IS_ERR(tk)) {
1029                 ret = PTR_ERR(tk);
1030                 /* This must return -ENOMEM, else there is a bug */
1031                 WARN_ON_ONCE(ret != -ENOMEM);
1032                 goto out;       /* We know tk is not allocated */
1033         }
1034
1035         /* parse arguments */
1036         for (i = 0; i < argc; i++) {
1037                 trace_probe_log_set_index(i + 2);
1038                 ctx.offset = 0;
1039                 ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], &ctx);
1040                 if (ret)
1041                         goto error;     /* This can be -ENOMEM */
1042         }
1043         /* entry handler for kretprobe */
1044         if (is_return && tk->tp.entry_arg) {
1045                 tk->rp.entry_handler = trace_kprobe_entry_handler;
1046                 tk->rp.data_size = traceprobe_get_entry_data_size(&tk->tp);
1047         }
1048
1049         ptype = is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
1050         ret = traceprobe_set_print_fmt(&tk->tp, ptype);
1051         if (ret < 0)
1052                 goto error;
1053
1054         ret = register_trace_kprobe(tk);
1055         if (ret) {
1056                 trace_probe_log_set_index(1);
1057                 if (ret == -EILSEQ)
1058                         trace_probe_log_err(0, BAD_INSN_BNDRY);
1059                 else if (ret == -ENOENT)
1060                         trace_probe_log_err(0, BAD_PROBE_ADDR);
1061                 else if (ret != -ENOMEM && ret != -EEXIST)
1062                         trace_probe_log_err(0, FAIL_REG_PROBE);
1063                 goto error;
1064         }
1065
1066 out:
1067         traceprobe_finish_parse(&ctx);
1068         trace_probe_log_clear();
1069         kfree(new_argv);
1070         kfree(symbol);
1071         kfree(dbuf);
1072         return ret;
1073
1074 parse_error:
1075         ret = -EINVAL;
1076 error:
1077         free_trace_kprobe(tk);
1078         goto out;
1079 }
1080
1081 static int trace_kprobe_create(const char *raw_command)
1082 {
1083         return trace_probe_create(raw_command, __trace_kprobe_create);
1084 }
1085
1086 static int create_or_delete_trace_kprobe(const char *raw_command)
1087 {
1088         int ret;
1089
1090         if (raw_command[0] == '-')
1091                 return dyn_event_release(raw_command, &trace_kprobe_ops);
1092
1093         ret = trace_kprobe_create(raw_command);
1094         return ret == -ECANCELED ? -EINVAL : ret;
1095 }
1096
1097 static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
1098 {
1099         return create_or_delete_trace_kprobe(cmd->seq.buffer);
1100 }
1101
1102 /**
1103  * kprobe_event_cmd_init - Initialize a kprobe event command object
1104  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1105  * @buf: A pointer to the buffer used to build the command
1106  * @maxlen: The length of the buffer passed in @buf
1107  *
1108  * Initialize a synthetic event command object.  Use this before
1109  * calling any of the other kprobe_event functions.
1110  */
1111 void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1112 {
1113         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
1114                           trace_kprobe_run_command);
1115 }
1116 EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
1117
1118 /**
1119  * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
1120  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1121  * @kretprobe: Is this a return probe?
1122  * @name: The name of the kprobe event
1123  * @loc: The location of the kprobe event
1124  * @...: Variable number of arg (pairs), one pair for each field
1125  *
1126  * NOTE: Users normally won't want to call this function directly, but
1127  * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
1128  * adds a NULL to the end of the arg list.  If this function is used
1129  * directly, make sure the last arg in the variable arg list is NULL.
1130  *
1131  * Generate a kprobe event command to be executed by
1132  * kprobe_event_gen_cmd_end().  This function can be used to generate the
1133  * complete command or only the first part of it; in the latter case,
1134  * kprobe_event_add_fields() can be used to add more fields following this.
1135  *
1136  * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
1137  * returns -EINVAL if @loc == NULL.
1138  *
1139  * Return: 0 if successful, error otherwise.
1140  */
1141 int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
1142                                  const char *name, const char *loc, ...)
1143 {
1144         char buf[MAX_EVENT_NAME_LEN];
1145         struct dynevent_arg arg;
1146         va_list args;
1147         int ret;
1148
1149         if (cmd->type != DYNEVENT_TYPE_KPROBE)
1150                 return -EINVAL;
1151
1152         if (!loc)
1153                 return -EINVAL;
1154
1155         if (kretprobe)
1156                 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
1157         else
1158                 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
1159
1160         ret = dynevent_str_add(cmd, buf);
1161         if (ret)
1162                 return ret;
1163
1164         dynevent_arg_init(&arg, 0);
1165         arg.str = loc;
1166         ret = dynevent_arg_add(cmd, &arg, NULL);
1167         if (ret)
1168                 return ret;
1169
1170         va_start(args, loc);
1171         for (;;) {
1172                 const char *field;
1173
1174                 field = va_arg(args, const char *);
1175                 if (!field)
1176                         break;
1177
1178                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1179                         ret = -EINVAL;
1180                         break;
1181                 }
1182
1183                 arg.str = field;
1184                 ret = dynevent_arg_add(cmd, &arg, NULL);
1185                 if (ret)
1186                         break;
1187         }
1188         va_end(args);
1189
1190         return ret;
1191 }
1192 EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
1193
1194 /**
1195  * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
1196  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1197  * @...: Variable number of arg (pairs), one pair for each field
1198  *
1199  * NOTE: Users normally won't want to call this function directly, but
1200  * rather use the kprobe_event_add_fields() wrapper, which
1201  * automatically adds a NULL to the end of the arg list.  If this
1202  * function is used directly, make sure the last arg in the variable
1203  * arg list is NULL.
1204  *
1205  * Add probe fields to an existing kprobe command using a variable
1206  * list of args.  Fields are added in the same order they're listed.
1207  *
1208  * Return: 0 if successful, error otherwise.
1209  */
1210 int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
1211 {
1212         struct dynevent_arg arg;
1213         va_list args;
1214         int ret = 0;
1215
1216         if (cmd->type != DYNEVENT_TYPE_KPROBE)
1217                 return -EINVAL;
1218
1219         dynevent_arg_init(&arg, 0);
1220
1221         va_start(args, cmd);
1222         for (;;) {
1223                 const char *field;
1224
1225                 field = va_arg(args, const char *);
1226                 if (!field)
1227                         break;
1228
1229                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1230                         ret = -EINVAL;
1231                         break;
1232                 }
1233
1234                 arg.str = field;
1235                 ret = dynevent_arg_add(cmd, &arg, NULL);
1236                 if (ret)
1237                         break;
1238         }
1239         va_end(args);
1240
1241         return ret;
1242 }
1243 EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
1244
1245 /**
1246  * kprobe_event_delete - Delete a kprobe event
1247  * @name: The name of the kprobe event to delete
1248  *
1249  * Delete a kprobe event with the give @name from kernel code rather
1250  * than directly from the command line.
1251  *
1252  * Return: 0 if successful, error otherwise.
1253  */
1254 int kprobe_event_delete(const char *name)
1255 {
1256         char buf[MAX_EVENT_NAME_LEN];
1257
1258         snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
1259
1260         return create_or_delete_trace_kprobe(buf);
1261 }
1262 EXPORT_SYMBOL_GPL(kprobe_event_delete);
1263
1264 static int trace_kprobe_release(struct dyn_event *ev)
1265 {
1266         struct trace_kprobe *tk = to_trace_kprobe(ev);
1267         int ret = unregister_trace_kprobe(tk);
1268
1269         if (!ret)
1270                 free_trace_kprobe(tk);
1271         return ret;
1272 }
1273
1274 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
1275 {
1276         struct trace_kprobe *tk = to_trace_kprobe(ev);
1277         int i;
1278
1279         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
1280         if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
1281                 seq_printf(m, "%d", tk->rp.maxactive);
1282         seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
1283                                 trace_probe_name(&tk->tp));
1284
1285         if (!tk->symbol)
1286                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
1287         else if (tk->rp.kp.offset)
1288                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
1289                            tk->rp.kp.offset);
1290         else
1291                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
1292
1293         for (i = 0; i < tk->tp.nr_args; i++)
1294                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
1295         seq_putc(m, '\n');
1296
1297         return 0;
1298 }
1299
1300 static int probes_seq_show(struct seq_file *m, void *v)
1301 {
1302         struct dyn_event *ev = v;
1303
1304         if (!is_trace_kprobe(ev))
1305                 return 0;
1306
1307         return trace_kprobe_show(m, ev);
1308 }
1309
1310 static const struct seq_operations probes_seq_op = {
1311         .start  = dyn_event_seq_start,
1312         .next   = dyn_event_seq_next,
1313         .stop   = dyn_event_seq_stop,
1314         .show   = probes_seq_show
1315 };
1316
1317 static int probes_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         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1326                 ret = dyn_events_release_all(&trace_kprobe_ops);
1327                 if (ret < 0)
1328                         return ret;
1329         }
1330
1331         return seq_open(file, &probes_seq_op);
1332 }
1333
1334 static ssize_t probes_write(struct file *file, const char __user *buffer,
1335                             size_t count, loff_t *ppos)
1336 {
1337         return trace_parse_run_command(file, buffer, count, ppos,
1338                                        create_or_delete_trace_kprobe);
1339 }
1340
1341 static const struct file_operations kprobe_events_ops = {
1342         .owner          = THIS_MODULE,
1343         .open           = probes_open,
1344         .read           = seq_read,
1345         .llseek         = seq_lseek,
1346         .release        = seq_release,
1347         .write          = probes_write,
1348 };
1349
1350 static unsigned long trace_kprobe_missed(struct trace_kprobe *tk)
1351 {
1352         return trace_kprobe_is_return(tk) ?
1353                 tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed;
1354 }
1355
1356 /* Probes profiling interfaces */
1357 static int probes_profile_seq_show(struct seq_file *m, void *v)
1358 {
1359         struct dyn_event *ev = v;
1360         struct trace_kprobe *tk;
1361         unsigned long nmissed;
1362
1363         if (!is_trace_kprobe(ev))
1364                 return 0;
1365
1366         tk = to_trace_kprobe(ev);
1367         nmissed = trace_kprobe_missed(tk);
1368         seq_printf(m, "  %-44s %15lu %15lu\n",
1369                    trace_probe_name(&tk->tp),
1370                    trace_kprobe_nhit(tk),
1371                    nmissed);
1372
1373         return 0;
1374 }
1375
1376 static const struct seq_operations profile_seq_op = {
1377         .start  = dyn_event_seq_start,
1378         .next   = dyn_event_seq_next,
1379         .stop   = dyn_event_seq_stop,
1380         .show   = probes_profile_seq_show
1381 };
1382
1383 static int profile_open(struct inode *inode, struct file *file)
1384 {
1385         int ret;
1386
1387         ret = security_locked_down(LOCKDOWN_TRACEFS);
1388         if (ret)
1389                 return ret;
1390
1391         return seq_open(file, &profile_seq_op);
1392 }
1393
1394 static const struct file_operations kprobe_profile_ops = {
1395         .owner          = THIS_MODULE,
1396         .open           = profile_open,
1397         .read           = seq_read,
1398         .llseek         = seq_lseek,
1399         .release        = seq_release,
1400 };
1401
1402 /* Note that we don't verify it, since the code does not come from user space */
1403 static int
1404 process_fetch_insn(struct fetch_insn *code, void *rec, void *edata,
1405                    void *dest, void *base)
1406 {
1407         struct pt_regs *regs = rec;
1408         unsigned long val;
1409         int ret;
1410
1411 retry:
1412         /* 1st stage: get value from context */
1413         switch (code->op) {
1414         case FETCH_OP_REG:
1415                 val = regs_get_register(regs, code->param);
1416                 break;
1417         case FETCH_OP_STACK:
1418                 val = regs_get_kernel_stack_nth(regs, code->param);
1419                 break;
1420         case FETCH_OP_STACKP:
1421                 val = kernel_stack_pointer(regs);
1422                 break;
1423         case FETCH_OP_RETVAL:
1424                 val = regs_return_value(regs);
1425                 break;
1426 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1427         case FETCH_OP_ARG:
1428                 val = regs_get_kernel_argument(regs, code->param);
1429                 break;
1430         case FETCH_OP_EDATA:
1431                 val = *(unsigned long *)((unsigned long)edata + code->offset);
1432                 break;
1433 #endif
1434         case FETCH_NOP_SYMBOL:  /* Ignore a place holder */
1435                 code++;
1436                 goto retry;
1437         default:
1438                 ret = process_common_fetch_insn(code, &val);
1439                 if (ret < 0)
1440                         return ret;
1441         }
1442         code++;
1443
1444         return process_fetch_insn_bottom(code, val, dest, base);
1445 }
1446 NOKPROBE_SYMBOL(process_fetch_insn)
1447
1448 /* Kprobe handler */
1449 static nokprobe_inline void
1450 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1451                     struct trace_event_file *trace_file)
1452 {
1453         struct kprobe_trace_entry_head *entry;
1454         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1455         struct trace_event_buffer fbuffer;
1456         int dsize;
1457
1458         WARN_ON(call != trace_file->event_call);
1459
1460         if (trace_trigger_soft_disabled(trace_file))
1461                 return;
1462
1463         dsize = __get_data_size(&tk->tp, regs, NULL);
1464
1465         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1466                                            sizeof(*entry) + tk->tp.size + dsize);
1467         if (!entry)
1468                 return;
1469
1470         fbuffer.regs = regs;
1471         entry->ip = (unsigned long)tk->rp.kp.addr;
1472         store_trace_args(&entry[1], &tk->tp, regs, NULL, sizeof(*entry), dsize);
1473
1474         trace_event_buffer_commit(&fbuffer);
1475 }
1476
1477 static void
1478 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1479 {
1480         struct event_file_link *link;
1481
1482         trace_probe_for_each_link_rcu(link, &tk->tp)
1483                 __kprobe_trace_func(tk, regs, link->file);
1484 }
1485 NOKPROBE_SYMBOL(kprobe_trace_func);
1486
1487 /* Kretprobe handler */
1488
1489 static int trace_kprobe_entry_handler(struct kretprobe_instance *ri,
1490                                       struct pt_regs *regs)
1491 {
1492         struct kretprobe *rp = get_kretprobe(ri);
1493         struct trace_kprobe *tk;
1494
1495         /*
1496          * There is a small chance that get_kretprobe(ri) returns NULL when
1497          * the kretprobe is unregister on another CPU between kretprobe's
1498          * trampoline_handler and this function.
1499          */
1500         if (unlikely(!rp))
1501                 return -ENOENT;
1502
1503         tk = container_of(rp, struct trace_kprobe, rp);
1504
1505         /* store argument values into ri->data as entry data */
1506         if (tk->tp.entry_arg)
1507                 store_trace_entry_data(ri->data, &tk->tp, regs);
1508
1509         return 0;
1510 }
1511
1512
1513 static nokprobe_inline void
1514 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1515                        struct pt_regs *regs,
1516                        struct trace_event_file *trace_file)
1517 {
1518         struct kretprobe_trace_entry_head *entry;
1519         struct trace_event_buffer fbuffer;
1520         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1521         int dsize;
1522
1523         WARN_ON(call != trace_file->event_call);
1524
1525         if (trace_trigger_soft_disabled(trace_file))
1526                 return;
1527
1528         dsize = __get_data_size(&tk->tp, regs, ri->data);
1529
1530         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1531                                            sizeof(*entry) + tk->tp.size + dsize);
1532         if (!entry)
1533                 return;
1534
1535         fbuffer.regs = regs;
1536         entry->func = (unsigned long)tk->rp.kp.addr;
1537         entry->ret_ip = get_kretprobe_retaddr(ri);
1538         store_trace_args(&entry[1], &tk->tp, regs, ri->data, sizeof(*entry), dsize);
1539
1540         trace_event_buffer_commit(&fbuffer);
1541 }
1542
1543 static void
1544 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1545                      struct pt_regs *regs)
1546 {
1547         struct event_file_link *link;
1548
1549         trace_probe_for_each_link_rcu(link, &tk->tp)
1550                 __kretprobe_trace_func(tk, ri, regs, link->file);
1551 }
1552 NOKPROBE_SYMBOL(kretprobe_trace_func);
1553
1554 /* Event entry printers */
1555 static enum print_line_t
1556 print_kprobe_event(struct trace_iterator *iter, int flags,
1557                    struct trace_event *event)
1558 {
1559         struct kprobe_trace_entry_head *field;
1560         struct trace_seq *s = &iter->seq;
1561         struct trace_probe *tp;
1562
1563         field = (struct kprobe_trace_entry_head *)iter->ent;
1564         tp = trace_probe_primary_from_call(
1565                 container_of(event, struct trace_event_call, event));
1566         if (WARN_ON_ONCE(!tp))
1567                 goto out;
1568
1569         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1570
1571         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1572                 goto out;
1573
1574         trace_seq_putc(s, ')');
1575
1576         if (trace_probe_print_args(s, tp->args, tp->nr_args,
1577                              (u8 *)&field[1], field) < 0)
1578                 goto out;
1579
1580         trace_seq_putc(s, '\n');
1581  out:
1582         return trace_handle_return(s);
1583 }
1584
1585 static enum print_line_t
1586 print_kretprobe_event(struct trace_iterator *iter, int flags,
1587                       struct trace_event *event)
1588 {
1589         struct kretprobe_trace_entry_head *field;
1590         struct trace_seq *s = &iter->seq;
1591         struct trace_probe *tp;
1592
1593         field = (struct kretprobe_trace_entry_head *)iter->ent;
1594         tp = trace_probe_primary_from_call(
1595                 container_of(event, struct trace_event_call, event));
1596         if (WARN_ON_ONCE(!tp))
1597                 goto out;
1598
1599         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1600
1601         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1602                 goto out;
1603
1604         trace_seq_puts(s, " <- ");
1605
1606         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1607                 goto out;
1608
1609         trace_seq_putc(s, ')');
1610
1611         if (trace_probe_print_args(s, tp->args, tp->nr_args,
1612                              (u8 *)&field[1], field) < 0)
1613                 goto out;
1614
1615         trace_seq_putc(s, '\n');
1616
1617  out:
1618         return trace_handle_return(s);
1619 }
1620
1621
1622 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1623 {
1624         int ret;
1625         struct kprobe_trace_entry_head field;
1626         struct trace_probe *tp;
1627
1628         tp = trace_probe_primary_from_call(event_call);
1629         if (WARN_ON_ONCE(!tp))
1630                 return -ENOENT;
1631
1632         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1633
1634         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1635 }
1636
1637 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1638 {
1639         int ret;
1640         struct kretprobe_trace_entry_head field;
1641         struct trace_probe *tp;
1642
1643         tp = trace_probe_primary_from_call(event_call);
1644         if (WARN_ON_ONCE(!tp))
1645                 return -ENOENT;
1646
1647         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1648         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1649
1650         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1651 }
1652
1653 #ifdef CONFIG_PERF_EVENTS
1654
1655 /* Kprobe profile handler */
1656 static int
1657 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1658 {
1659         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1660         struct kprobe_trace_entry_head *entry;
1661         struct hlist_head *head;
1662         int size, __size, dsize;
1663         int rctx;
1664
1665         if (bpf_prog_array_valid(call)) {
1666                 unsigned long orig_ip = instruction_pointer(regs);
1667                 int ret;
1668
1669                 ret = trace_call_bpf(call, regs);
1670
1671                 /*
1672                  * We need to check and see if we modified the pc of the
1673                  * pt_regs, and if so return 1 so that we don't do the
1674                  * single stepping.
1675                  */
1676                 if (orig_ip != instruction_pointer(regs))
1677                         return 1;
1678                 if (!ret)
1679                         return 0;
1680         }
1681
1682         head = this_cpu_ptr(call->perf_events);
1683         if (hlist_empty(head))
1684                 return 0;
1685
1686         dsize = __get_data_size(&tk->tp, regs, NULL);
1687         __size = sizeof(*entry) + tk->tp.size + dsize;
1688         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1689         size -= sizeof(u32);
1690
1691         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1692         if (!entry)
1693                 return 0;
1694
1695         entry->ip = (unsigned long)tk->rp.kp.addr;
1696         memset(&entry[1], 0, dsize);
1697         store_trace_args(&entry[1], &tk->tp, regs, NULL, sizeof(*entry), dsize);
1698         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1699                               head, NULL);
1700         return 0;
1701 }
1702 NOKPROBE_SYMBOL(kprobe_perf_func);
1703
1704 /* Kretprobe profile handler */
1705 static void
1706 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1707                     struct pt_regs *regs)
1708 {
1709         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1710         struct kretprobe_trace_entry_head *entry;
1711         struct hlist_head *head;
1712         int size, __size, dsize;
1713         int rctx;
1714
1715         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1716                 return;
1717
1718         head = this_cpu_ptr(call->perf_events);
1719         if (hlist_empty(head))
1720                 return;
1721
1722         dsize = __get_data_size(&tk->tp, regs, ri->data);
1723         __size = sizeof(*entry) + tk->tp.size + dsize;
1724         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1725         size -= sizeof(u32);
1726
1727         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1728         if (!entry)
1729                 return;
1730
1731         entry->func = (unsigned long)tk->rp.kp.addr;
1732         entry->ret_ip = get_kretprobe_retaddr(ri);
1733         store_trace_args(&entry[1], &tk->tp, regs, ri->data, sizeof(*entry), dsize);
1734         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1735                               head, NULL);
1736 }
1737 NOKPROBE_SYMBOL(kretprobe_perf_func);
1738
1739 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1740                         const char **symbol, u64 *probe_offset,
1741                         u64 *probe_addr, unsigned long *missed,
1742                         bool perf_type_tracepoint)
1743 {
1744         const char *pevent = trace_event_name(event->tp_event);
1745         const char *group = event->tp_event->class->system;
1746         struct trace_kprobe *tk;
1747
1748         if (perf_type_tracepoint)
1749                 tk = find_trace_kprobe(pevent, group);
1750         else
1751                 tk = trace_kprobe_primary_from_call(event->tp_event);
1752         if (!tk)
1753                 return -EINVAL;
1754
1755         *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1756                                               : BPF_FD_TYPE_KPROBE;
1757         *probe_offset = tk->rp.kp.offset;
1758         *probe_addr = kallsyms_show_value(current_cred()) ?
1759                       (unsigned long)tk->rp.kp.addr : 0;
1760         *symbol = tk->symbol;
1761         if (missed)
1762                 *missed = trace_kprobe_missed(tk);
1763         return 0;
1764 }
1765 #endif  /* CONFIG_PERF_EVENTS */
1766
1767 /*
1768  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1769  *
1770  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1771  * lockless, but we can't race with this __init function.
1772  */
1773 static int kprobe_register(struct trace_event_call *event,
1774                            enum trace_reg type, void *data)
1775 {
1776         struct trace_event_file *file = data;
1777
1778         switch (type) {
1779         case TRACE_REG_REGISTER:
1780                 return enable_trace_kprobe(event, file);
1781         case TRACE_REG_UNREGISTER:
1782                 return disable_trace_kprobe(event, file);
1783
1784 #ifdef CONFIG_PERF_EVENTS
1785         case TRACE_REG_PERF_REGISTER:
1786                 return enable_trace_kprobe(event, NULL);
1787         case TRACE_REG_PERF_UNREGISTER:
1788                 return disable_trace_kprobe(event, NULL);
1789         case TRACE_REG_PERF_OPEN:
1790         case TRACE_REG_PERF_CLOSE:
1791         case TRACE_REG_PERF_ADD:
1792         case TRACE_REG_PERF_DEL:
1793                 return 0;
1794 #endif
1795         }
1796         return 0;
1797 }
1798
1799 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1800 {
1801         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1802         int ret = 0;
1803
1804         raw_cpu_inc(*tk->nhit);
1805
1806         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1807                 kprobe_trace_func(tk, regs);
1808 #ifdef CONFIG_PERF_EVENTS
1809         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1810                 ret = kprobe_perf_func(tk, regs);
1811 #endif
1812         return ret;
1813 }
1814 NOKPROBE_SYMBOL(kprobe_dispatcher);
1815
1816 static int
1817 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1818 {
1819         struct kretprobe *rp = get_kretprobe(ri);
1820         struct trace_kprobe *tk;
1821
1822         /*
1823          * There is a small chance that get_kretprobe(ri) returns NULL when
1824          * the kretprobe is unregister on another CPU between kretprobe's
1825          * trampoline_handler and this function.
1826          */
1827         if (unlikely(!rp))
1828                 return 0;
1829
1830         tk = container_of(rp, struct trace_kprobe, rp);
1831         raw_cpu_inc(*tk->nhit);
1832
1833         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1834                 kretprobe_trace_func(tk, ri, regs);
1835 #ifdef CONFIG_PERF_EVENTS
1836         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1837                 kretprobe_perf_func(tk, ri, regs);
1838 #endif
1839         return 0;       /* We don't tweak kernel, so just return 0 */
1840 }
1841 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1842
1843 static struct trace_event_functions kretprobe_funcs = {
1844         .trace          = print_kretprobe_event
1845 };
1846
1847 static struct trace_event_functions kprobe_funcs = {
1848         .trace          = print_kprobe_event
1849 };
1850
1851 static struct trace_event_fields kretprobe_fields_array[] = {
1852         { .type = TRACE_FUNCTION_TYPE,
1853           .define_fields = kretprobe_event_define_fields },
1854         {}
1855 };
1856
1857 static struct trace_event_fields kprobe_fields_array[] = {
1858         { .type = TRACE_FUNCTION_TYPE,
1859           .define_fields = kprobe_event_define_fields },
1860         {}
1861 };
1862
1863 static inline void init_trace_event_call(struct trace_kprobe *tk)
1864 {
1865         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1866
1867         if (trace_kprobe_is_return(tk)) {
1868                 call->event.funcs = &kretprobe_funcs;
1869                 call->class->fields_array = kretprobe_fields_array;
1870         } else {
1871                 call->event.funcs = &kprobe_funcs;
1872                 call->class->fields_array = kprobe_fields_array;
1873         }
1874
1875         call->flags = TRACE_EVENT_FL_KPROBE;
1876         call->class->reg = kprobe_register;
1877 }
1878
1879 static int register_kprobe_event(struct trace_kprobe *tk)
1880 {
1881         init_trace_event_call(tk);
1882
1883         return trace_probe_register_event_call(&tk->tp);
1884 }
1885
1886 static int unregister_kprobe_event(struct trace_kprobe *tk)
1887 {
1888         return trace_probe_unregister_event_call(&tk->tp);
1889 }
1890
1891 #ifdef CONFIG_PERF_EVENTS
1892
1893 /* create a trace_kprobe, but don't add it to global lists */
1894 struct trace_event_call *
1895 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1896                           bool is_return)
1897 {
1898         enum probe_print_type ptype;
1899         struct trace_kprobe *tk;
1900         int ret;
1901         char *event;
1902
1903         if (func) {
1904                 ret = validate_probe_symbol(func);
1905                 if (ret)
1906                         return ERR_PTR(ret);
1907         }
1908
1909         /*
1910          * local trace_kprobes are not added to dyn_event, so they are never
1911          * searched in find_trace_kprobe(). Therefore, there is no concern of
1912          * duplicated name here.
1913          */
1914         event = func ? func : "DUMMY_EVENT";
1915
1916         tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1917                                 offs, 0 /* maxactive */, 0 /* nargs */,
1918                                 is_return);
1919
1920         if (IS_ERR(tk)) {
1921                 pr_info("Failed to allocate trace_probe.(%d)\n",
1922                         (int)PTR_ERR(tk));
1923                 return ERR_CAST(tk);
1924         }
1925
1926         init_trace_event_call(tk);
1927
1928         ptype = trace_kprobe_is_return(tk) ?
1929                 PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
1930         if (traceprobe_set_print_fmt(&tk->tp, ptype) < 0) {
1931                 ret = -ENOMEM;
1932                 goto error;
1933         }
1934
1935         ret = __register_trace_kprobe(tk);
1936         if (ret < 0)
1937                 goto error;
1938
1939         return trace_probe_event_call(&tk->tp);
1940 error:
1941         free_trace_kprobe(tk);
1942         return ERR_PTR(ret);
1943 }
1944
1945 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1946 {
1947         struct trace_kprobe *tk;
1948
1949         tk = trace_kprobe_primary_from_call(event_call);
1950         if (unlikely(!tk))
1951                 return;
1952
1953         if (trace_probe_is_enabled(&tk->tp)) {
1954                 WARN_ON(1);
1955                 return;
1956         }
1957
1958         __unregister_trace_kprobe(tk);
1959
1960         free_trace_kprobe(tk);
1961 }
1962 #endif /* CONFIG_PERF_EVENTS */
1963
1964 static __init void enable_boot_kprobe_events(void)
1965 {
1966         struct trace_array *tr = top_trace_array();
1967         struct trace_event_file *file;
1968         struct trace_kprobe *tk;
1969         struct dyn_event *pos;
1970
1971         mutex_lock(&event_mutex);
1972         for_each_trace_kprobe(tk, pos) {
1973                 list_for_each_entry(file, &tr->events, list)
1974                         if (file->event_call == trace_probe_event_call(&tk->tp))
1975                                 trace_event_enable_disable(file, 1, 0);
1976         }
1977         mutex_unlock(&event_mutex);
1978 }
1979
1980 static __init void setup_boot_kprobe_events(void)
1981 {
1982         char *p, *cmd = kprobe_boot_events_buf;
1983         int ret;
1984
1985         strreplace(kprobe_boot_events_buf, ',', ' ');
1986
1987         while (cmd && *cmd != '\0') {
1988                 p = strchr(cmd, ';');
1989                 if (p)
1990                         *p++ = '\0';
1991
1992                 ret = create_or_delete_trace_kprobe(cmd);
1993                 if (ret)
1994                         pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1995
1996                 cmd = p;
1997         }
1998
1999         enable_boot_kprobe_events();
2000 }
2001
2002 /*
2003  * Register dynevent at core_initcall. This allows kernel to setup kprobe
2004  * events in postcore_initcall without tracefs.
2005  */
2006 static __init int init_kprobe_trace_early(void)
2007 {
2008         int ret;
2009
2010         ret = dyn_event_register(&trace_kprobe_ops);
2011         if (ret)
2012                 return ret;
2013
2014         if (trace_kprobe_register_module_notifier())
2015                 return -EINVAL;
2016
2017         return 0;
2018 }
2019 core_initcall(init_kprobe_trace_early);
2020
2021 /* Make a tracefs interface for controlling probe points */
2022 static __init int init_kprobe_trace(void)
2023 {
2024         int ret;
2025
2026         ret = tracing_init_dentry();
2027         if (ret)
2028                 return 0;
2029
2030         /* Event list interface */
2031         trace_create_file("kprobe_events", TRACE_MODE_WRITE,
2032                           NULL, NULL, &kprobe_events_ops);
2033
2034         /* Profile interface */
2035         trace_create_file("kprobe_profile", TRACE_MODE_READ,
2036                           NULL, NULL, &kprobe_profile_ops);
2037
2038         setup_boot_kprobe_events();
2039
2040         return 0;
2041 }
2042 fs_initcall(init_kprobe_trace);
2043
2044
2045 #ifdef CONFIG_FTRACE_STARTUP_TEST
2046 static __init struct trace_event_file *
2047 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
2048 {
2049         struct trace_event_file *file;
2050
2051         list_for_each_entry(file, &tr->events, list)
2052                 if (file->event_call == trace_probe_event_call(&tk->tp))
2053                         return file;
2054
2055         return NULL;
2056 }
2057
2058 /*
2059  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
2060  * stage, we can do this lockless.
2061  */
2062 static __init int kprobe_trace_self_tests_init(void)
2063 {
2064         int ret, warn = 0;
2065         int (*target)(int, int, int, int, int, int);
2066         struct trace_kprobe *tk;
2067         struct trace_event_file *file;
2068
2069         if (tracing_is_disabled())
2070                 return -ENODEV;
2071
2072         if (tracing_selftest_disabled)
2073                 return 0;
2074
2075         target = kprobe_trace_selftest_target;
2076
2077         pr_info("Testing kprobe tracing: ");
2078
2079         ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
2080         if (WARN_ONCE(ret, "error on probing function entry.")) {
2081                 warn++;
2082         } else {
2083                 /* Enable trace point */
2084                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2085                 if (WARN_ONCE(tk == NULL, "error on probing function entry.")) {
2086                         warn++;
2087                 } else {
2088                         file = find_trace_probe_file(tk, top_trace_array());
2089                         if (WARN_ONCE(file == NULL, "error on getting probe file.")) {
2090                                 warn++;
2091                         } else
2092                                 enable_trace_kprobe(
2093                                         trace_probe_event_call(&tk->tp), file);
2094                 }
2095         }
2096
2097         ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
2098         if (WARN_ONCE(ret, "error on probing function return.")) {
2099                 warn++;
2100         } else {
2101                 /* Enable trace point */
2102                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2103                 if (WARN_ONCE(tk == NULL, "error on getting 2nd new probe.")) {
2104                         warn++;
2105                 } else {
2106                         file = find_trace_probe_file(tk, top_trace_array());
2107                         if (WARN_ONCE(file == NULL, "error on getting probe file.")) {
2108                                 warn++;
2109                         } else
2110                                 enable_trace_kprobe(
2111                                         trace_probe_event_call(&tk->tp), file);
2112                 }
2113         }
2114
2115         if (warn)
2116                 goto end;
2117
2118         ret = target(1, 2, 3, 4, 5, 6);
2119
2120         /*
2121          * Not expecting an error here, the check is only to prevent the
2122          * optimizer from removing the call to target() as otherwise there
2123          * are no side-effects and the call is never performed.
2124          */
2125         if (ret != 21)
2126                 warn++;
2127
2128         /* Disable trace points before removing it */
2129         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2130         if (WARN_ONCE(tk == NULL, "error on getting test probe.")) {
2131                 warn++;
2132         } else {
2133                 if (WARN_ONCE(trace_kprobe_nhit(tk) != 1,
2134                                  "incorrect number of testprobe hits."))
2135                         warn++;
2136
2137                 file = find_trace_probe_file(tk, top_trace_array());
2138                 if (WARN_ONCE(file == NULL, "error on getting probe file.")) {
2139                         warn++;
2140                 } else
2141                         disable_trace_kprobe(
2142                                 trace_probe_event_call(&tk->tp), file);
2143         }
2144
2145         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2146         if (WARN_ONCE(tk == NULL, "error on getting 2nd test probe.")) {
2147                 warn++;
2148         } else {
2149                 if (WARN_ONCE(trace_kprobe_nhit(tk) != 1,
2150                                  "incorrect number of testprobe2 hits."))
2151                         warn++;
2152
2153                 file = find_trace_probe_file(tk, top_trace_array());
2154                 if (WARN_ONCE(file == NULL, "error on getting probe file.")) {
2155                         warn++;
2156                 } else
2157                         disable_trace_kprobe(
2158                                 trace_probe_event_call(&tk->tp), file);
2159         }
2160
2161         ret = create_or_delete_trace_kprobe("-:testprobe");
2162         if (WARN_ONCE(ret, "error on deleting a probe."))
2163                 warn++;
2164
2165         ret = create_or_delete_trace_kprobe("-:testprobe2");
2166         if (WARN_ONCE(ret, "error on deleting a probe."))
2167                 warn++;
2168
2169
2170 end:
2171         /*
2172          * Wait for the optimizer work to finish. Otherwise it might fiddle
2173          * with probes in already freed __init text.
2174          */
2175         wait_for_kprobe_optimizer();
2176         if (warn)
2177                 pr_cont("NG: Some tests are failed. Please check them.\n");
2178         else
2179                 pr_cont("OK\n");
2180         return 0;
2181 }
2182
2183 late_initcall(kprobe_trace_self_tests_init);
2184
2185 #endif