kernel/trace/trace_kprobe.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Kprobes-based tracing events
   4  *
   5  * Created by Masami Hiramatsu <mhiramat@redhat.com>
   6  *
   7  */
   8 #define pr_fmt(fmt)     "trace_kprobe: " fmt
   9
  10 #include <linux/security.h>
  11 #include <linux/module.h>
  12 #include <linux/uaccess.h>
  13 #include <linux/rculist.h>
  14 #include <linux/error-injection.h>
  15
  16 #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
  17
  18 #include "trace_dynevent.h"
  19 #include "trace_kprobe_selftest.h"
  20 #include "trace_probe.h"
  21 #include "trace_probe_tmpl.h"
  22
  23 #define KPROBE_EVENT_SYSTEM "kprobes"
  24 #define KRETPROBE_MAXACTIVE_MAX 4096
  25 #define MAX_KPROBE_CMDLINE_SIZE 1024
  26
  27 /* Kprobe early definition from command line */
  28 static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
  29 static bool kprobe_boot_events_enabled __initdata;
  30
  31 static int __init set_kprobe_boot_events(char *str)
  32 {
  33         strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
  34         return 0;
  35 }
  36 __setup("kprobe_event=", set_kprobe_boot_events);
  37
  38 static int trace_kprobe_create(int argc, const char **argv);
  39 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
  40 static int trace_kprobe_release(struct dyn_event *ev);
  41 static bool trace_kprobe_is_busy(struct dyn_event *ev);
  42 static bool trace_kprobe_match(const char *system, const char *event,
  43                         int argc, const char **argv, struct dyn_event *ev);
  44
  45 static struct dyn_event_operations trace_kprobe_ops = {
  46         .create = trace_kprobe_create,
  47         .show = trace_kprobe_show,
  48         .is_busy = trace_kprobe_is_busy,
  49         .free = trace_kprobe_release,
  50         .match = trace_kprobe_match,
  51 };
  52
  53 /*
  54  * Kprobe event core functions
  55  */
  56 struct trace_kprobe {
  57         struct dyn_event        devent;
  58         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
  59         unsigned long __percpu *nhit;
  60         const char              *symbol;        /* symbol name */
  61         struct trace_probe      tp;
  62 };
  63
  64 static bool is_trace_kprobe(struct dyn_event *ev)
  65 {
  66         return ev->ops == &trace_kprobe_ops;
  67 }
  68
  69 static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
  70 {
  71         return container_of(ev, struct trace_kprobe, devent);
  72 }
  73
  74 /**
  75  * for_each_trace_kprobe - iterate over the trace_kprobe list
  76  * @pos:        the struct trace_kprobe * for each entry
  77  * @dpos:       the struct dyn_event * to use as a loop cursor
  78  */
  79 #define for_each_trace_kprobe(pos, dpos)        \
  80         for_each_dyn_event(dpos)                \
  81                 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
  82
  83 #define SIZEOF_TRACE_KPROBE(n)                          \
  84         (offsetof(struct trace_kprobe, tp.args) +       \
  85         (sizeof(struct probe_arg) * (n)))
  86
  87 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
  88 {
  89         return tk->rp.handler != NULL;
  90 }
  91
  92 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
  93 {
  94         return tk->symbol ? tk->symbol : "unknown";
  95 }
  96
  97 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
  98 {
  99         return tk->rp.kp.offset;
 100 }
 101
 102 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
 103 {
 104         return !!(kprobe_gone(&tk->rp.kp));
 105 }
 106
 107 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
 108                                                  struct module *mod)
 109 {
 110         int len = strlen(mod->name);
 111         const char *name = trace_kprobe_symbol(tk);
 112         return strncmp(mod->name, name, len) == 0 && name[len] == ':';
 113 }
 114
 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         mutex_lock(&module_mutex);
 127         ret = !!find_module(tk->symbol);
 128         mutex_unlock(&module_mutex);
 129         *p = ':';
 130
 131         return ret;
 132 }
 133
 134 static bool trace_kprobe_is_busy(struct dyn_event *ev)
 135 {
 136         struct trace_kprobe *tk = to_trace_kprobe(ev);
 137
 138         return trace_probe_is_enabled(&tk->tp);
 139 }
 140
 141 static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
 142                                             int argc, const char **argv)
 143 {
 144         char buf[MAX_ARGSTR_LEN + 1];
 145
 146         if (!argc)
 147                 return true;
 148
 149         if (!tk->symbol)
 150                 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
 151         else if (tk->rp.kp.offset)
 152                 snprintf(buf, sizeof(buf), "%s+%u",
 153                          trace_kprobe_symbol(tk), tk->rp.kp.offset);
 154         else
 155                 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
 156         if (strcmp(buf, argv[0]))
 157                 return false;
 158         argc--; argv++;
 159
 160         return trace_probe_match_command_args(&tk->tp, argc, argv);
 161 }
 162
 163 static bool trace_kprobe_match(const char *system, const char *event,
 164                         int argc, const char **argv, struct dyn_event *ev)
 165 {
 166         struct trace_kprobe *tk = to_trace_kprobe(ev);
 167
 168         return strcmp(trace_probe_name(&tk->tp), event) == 0 &&
 169             (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
 170             trace_kprobe_match_command_head(tk, argc, argv);
 171 }
 172
 173 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
 174 {
 175         unsigned long nhit = 0;
 176         int cpu;
 177
 178         for_each_possible_cpu(cpu)
 179                 nhit += *per_cpu_ptr(tk->nhit, cpu);
 180
 181         return nhit;
 182 }
 183
 184 static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk)
 185 {
 186         return !(list_empty(&tk->rp.kp.list) &&
 187                  hlist_unhashed(&tk->rp.kp.hlist));
 188 }
 189
 190 /* Return 0 if it fails to find the symbol address */
 191 static nokprobe_inline
 192 unsigned long trace_kprobe_address(struct trace_kprobe *tk)
 193 {
 194         unsigned long addr;
 195
 196         if (tk->symbol) {
 197                 addr = (unsigned long)
 198                         kallsyms_lookup_name(trace_kprobe_symbol(tk));
 199                 if (addr)
 200                         addr += tk->rp.kp.offset;
 201         } else {
 202                 addr = (unsigned long)tk->rp.kp.addr;
 203         }
 204         return addr;
 205 }
 206
 207 static nokprobe_inline struct trace_kprobe *
 208 trace_kprobe_primary_from_call(struct trace_event_call *call)
 209 {
 210         struct trace_probe *tp;
 211
 212         tp = trace_probe_primary_from_call(call);
 213         if (WARN_ON_ONCE(!tp))
 214                 return NULL;
 215
 216         return container_of(tp, struct trace_kprobe, tp);
 217 }
 218
 219 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
 220 {
 221         struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
 222
 223         return tk ? kprobe_on_func_entry(tk->rp.kp.addr,
 224                         tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
 225                         tk->rp.kp.addr ? 0 : tk->rp.kp.offset) : false;
 226 }
 227
 228 bool trace_kprobe_error_injectable(struct trace_event_call *call)
 229 {
 230         struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
 231
 232         return tk ? within_error_injection_list(trace_kprobe_address(tk)) :
 233                false;
 234 }
 235
 236 static int register_kprobe_event(struct trace_kprobe *tk);
 237 static int unregister_kprobe_event(struct trace_kprobe *tk);
 238
 239 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 240 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 241                                 struct pt_regs *regs);
 242
 243 static void free_trace_kprobe(struct trace_kprobe *tk)
 244 {
 245         if (tk) {
 246                 trace_probe_cleanup(&tk->tp);
 247                 kfree(tk->symbol);
 248                 free_percpu(tk->nhit);
 249                 kfree(tk);
 250         }
 251 }
 252
 253 /*
 254  * Allocate new trace_probe and initialize it (including kprobes).
 255  */
 256 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
 257                                              const char *event,
 258                                              void *addr,
 259                                              const char *symbol,
 260                                              unsigned long offs,
 261                                              int maxactive,
 262                                              int nargs, bool is_return)
 263 {
 264         struct trace_kprobe *tk;
 265         int ret = -ENOMEM;
 266
 267         tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
 268         if (!tk)
 269                 return ERR_PTR(ret);
 270
 271         tk->nhit = alloc_percpu(unsigned long);
 272         if (!tk->nhit)
 273                 goto error;
 274
 275         if (symbol) {
 276                 tk->symbol = kstrdup(symbol, GFP_KERNEL);
 277                 if (!tk->symbol)
 278                         goto error;
 279                 tk->rp.kp.symbol_name = tk->symbol;
 280                 tk->rp.kp.offset = offs;
 281         } else
 282                 tk->rp.kp.addr = addr;
 283
 284         if (is_return)
 285                 tk->rp.handler = kretprobe_dispatcher;
 286         else
 287                 tk->rp.kp.pre_handler = kprobe_dispatcher;
 288
 289         tk->rp.maxactive = maxactive;
 290         INIT_HLIST_NODE(&tk->rp.kp.hlist);
 291         INIT_LIST_HEAD(&tk->rp.kp.list);
 292
 293         ret = trace_probe_init(&tk->tp, event, group);
 294         if (ret < 0)
 295                 goto error;
 296
 297         dyn_event_init(&tk->devent, &trace_kprobe_ops);
 298         return tk;
 299 error:
 300         free_trace_kprobe(tk);
 301         return ERR_PTR(ret);
 302 }
 303
 304 static struct trace_kprobe *find_trace_kprobe(const char *event,
 305                                               const char *group)
 306 {
 307         struct dyn_event *pos;
 308         struct trace_kprobe *tk;
 309
 310         for_each_trace_kprobe(tk, pos)
 311                 if (strcmp(trace_probe_name(&tk->tp), event) == 0 &&
 312                     strcmp(trace_probe_group_name(&tk->tp), group) == 0)
 313                         return tk;
 314         return NULL;
 315 }
 316
 317 static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
 318 {
 319         int ret = 0;
 320
 321         if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) {
 322                 if (trace_kprobe_is_return(tk))
 323                         ret = enable_kretprobe(&tk->rp);
 324                 else
 325                         ret = enable_kprobe(&tk->rp.kp);
 326         }
 327
 328         return ret;
 329 }
 330
 331 static void __disable_trace_kprobe(struct trace_probe *tp)
 332 {
 333         struct trace_probe *pos;
 334         struct trace_kprobe *tk;
 335
 336         list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
 337                 tk = container_of(pos, struct trace_kprobe, tp);
 338                 if (!trace_kprobe_is_registered(tk))
 339                         continue;
 340                 if (trace_kprobe_is_return(tk))
 341                         disable_kretprobe(&tk->rp);
 342                 else
 343                         disable_kprobe(&tk->rp.kp);
 344         }
 345 }
 346
 347 /*
 348  * Enable trace_probe
 349  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
 350  */
 351 static int enable_trace_kprobe(struct trace_event_call *call,
 352                                 struct trace_event_file *file)
 353 {
 354         struct trace_probe *pos, *tp;
 355         struct trace_kprobe *tk;
 356         bool enabled;
 357         int ret = 0;
 358
 359         tp = trace_probe_primary_from_call(call);
 360         if (WARN_ON_ONCE(!tp))
 361                 return -ENODEV;
 362         enabled = trace_probe_is_enabled(tp);
 363
 364         /* This also changes "enabled" state */
 365         if (file) {
 366                 ret = trace_probe_add_file(tp, file);
 367                 if (ret)
 368                         return ret;
 369         } else
 370                 trace_probe_set_flag(tp, TP_FLAG_PROFILE);
 371
 372         if (enabled)
 373                 return 0;
 374
 375         list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
 376                 tk = container_of(pos, struct trace_kprobe, tp);
 377                 if (trace_kprobe_has_gone(tk))
 378                         continue;
 379                 ret = __enable_trace_kprobe(tk);
 380                 if (ret)
 381                         break;
 382                 enabled = true;
 383         }
 384
 385         if (ret) {
 386                 /* Failed to enable one of them. Roll back all */
 387                 if (enabled)
 388                         __disable_trace_kprobe(tp);
 389                 if (file)
 390                         trace_probe_remove_file(tp, file);
 391                 else
 392                         trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
 393         }
 394
 395         return ret;
 396 }
 397
 398 /*
 399  * Disable trace_probe
 400  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
 401  */
 402 static int disable_trace_kprobe(struct trace_event_call *call,
 403                                 struct trace_event_file *file)
 404 {
 405         struct trace_probe *tp;
 406
 407         tp = trace_probe_primary_from_call(call);
 408         if (WARN_ON_ONCE(!tp))
 409                 return -ENODEV;
 410
 411         if (file) {
 412                 if (!trace_probe_get_file_link(tp, file))
 413                         return -ENOENT;
 414                 if (!trace_probe_has_single_file(tp))
 415                         goto out;
 416                 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
 417         } else
 418                 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
 419
 420         if (!trace_probe_is_enabled(tp))
 421                 __disable_trace_kprobe(tp);
 422
 423  out:
 424         if (file)
 425                 /*
 426                  * Synchronization is done in below function. For perf event,
 427                  * file == NULL and perf_trace_event_unreg() calls
 428                  * tracepoint_synchronize_unregister() to ensure synchronize
 429                  * event. We don't need to care about it.
 430                  */
 431                 trace_probe_remove_file(tp, file);
 432
 433         return 0;
 434 }
 435
 436 #if defined(CONFIG_KPROBES_ON_FTRACE) && \
 437         !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
 438 static bool within_notrace_func(struct trace_kprobe *tk)
 439 {
 440         unsigned long offset, size, addr;
 441
 442         addr = trace_kprobe_address(tk);
 443         if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
 444                 return false;
 445
 446         /* Get the entry address of the target function */
 447         addr -= offset;
 448
 449         /*
 450          * Since ftrace_location_range() does inclusive range check, we need
 451          * to subtract 1 byte from the end address.
 452          */
 453         return !ftrace_location_range(addr, addr + size - 1);
 454 }
 455 #else
 456 #define within_notrace_func(tk) (false)
 457 #endif
 458
 459 /* Internal register function - just handle k*probes and flags */
 460 static int __register_trace_kprobe(struct trace_kprobe *tk)
 461 {
 462         int i, ret;
 463
 464         ret = security_locked_down(LOCKDOWN_KPROBES);
 465         if (ret)
 466                 return ret;
 467
 468         if (trace_kprobe_is_registered(tk))
 469                 return -EINVAL;
 470
 471         if (within_notrace_func(tk)) {
 472                 pr_warn("Could not probe notrace function %s\n",
 473                         trace_kprobe_symbol(tk));
 474                 return -EINVAL;
 475         }
 476
 477         for (i = 0; i < tk->tp.nr_args; i++) {
 478                 ret = traceprobe_update_arg(&tk->tp.args[i]);
 479                 if (ret)
 480                         return ret;
 481         }
 482
 483         /* Set/clear disabled flag according to tp->flag */
 484         if (trace_probe_is_enabled(&tk->tp))
 485                 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
 486         else
 487                 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 488
 489         if (trace_kprobe_is_return(tk))
 490                 ret = register_kretprobe(&tk->rp);
 491         else
 492                 ret = register_kprobe(&tk->rp.kp);
 493
 494         return ret;
 495 }
 496
 497 /* Internal unregister function - just handle k*probes and flags */
 498 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 499 {
 500         if (trace_kprobe_is_registered(tk)) {
 501                 if (trace_kprobe_is_return(tk))
 502                         unregister_kretprobe(&tk->rp);
 503                 else
 504                         unregister_kprobe(&tk->rp.kp);
 505                 /* Cleanup kprobe for reuse and mark it unregistered */
 506                 INIT_HLIST_NODE(&tk->rp.kp.hlist);
 507                 INIT_LIST_HEAD(&tk->rp.kp.list);
 508                 if (tk->rp.kp.symbol_name)
 509                         tk->rp.kp.addr = NULL;
 510         }
 511 }
 512
 513 /* Unregister a trace_probe and probe_event */
 514 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 515 {
 516         /* If other probes are on the event, just unregister kprobe */
 517         if (trace_probe_has_sibling(&tk->tp))
 518                 goto unreg;
 519
 520         /* Enabled event can not be unregistered */
 521         if (trace_probe_is_enabled(&tk->tp))
 522                 return -EBUSY;
 523
 524         /* Will fail if probe is being used by ftrace or perf */
 525         if (unregister_kprobe_event(tk))
 526                 return -EBUSY;
 527
 528 unreg:
 529         __unregister_trace_kprobe(tk);
 530         dyn_event_remove(&tk->devent);
 531         trace_probe_unlink(&tk->tp);
 532
 533         return 0;
 534 }
 535
 536 static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
 537                                          struct trace_kprobe *comp)
 538 {
 539         struct trace_probe_event *tpe = orig->tp.event;
 540         struct trace_probe *pos;
 541         int i;
 542
 543         list_for_each_entry(pos, &tpe->probes, list) {
 544                 orig = container_of(pos, struct trace_kprobe, tp);
 545                 if (strcmp(trace_kprobe_symbol(orig),
 546                            trace_kprobe_symbol(comp)) ||
 547                     trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
 548                         continue;
 549
 550                 /*
 551                  * trace_probe_compare_arg_type() ensured that nr_args and
 552                  * each argument name and type are same. Let's compare comm.
 553                  */
 554                 for (i = 0; i < orig->tp.nr_args; i++) {
 555                         if (strcmp(orig->tp.args[i].comm,
 556                                    comp->tp.args[i].comm))
 557                                 break;
 558                 }
 559
 560                 if (i == orig->tp.nr_args)
 561                         return true;
 562         }
 563
 564         return false;
 565 }
 566
 567 static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
 568 {
 569         int ret;
 570
 571         ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
 572         if (ret) {
 573                 /* Note that argument starts index = 2 */
 574                 trace_probe_log_set_index(ret + 1);
 575                 trace_probe_log_err(0, DIFF_ARG_TYPE);
 576                 return -EEXIST;
 577         }
 578         if (trace_kprobe_has_same_kprobe(to, tk)) {
 579                 trace_probe_log_set_index(0);
 580                 trace_probe_log_err(0, SAME_PROBE);
 581                 return -EEXIST;
 582         }
 583
 584         /* Append to existing event */
 585         ret = trace_probe_append(&tk->tp, &to->tp);
 586         if (ret)
 587                 return ret;
 588
 589         /* Register k*probe */
 590         ret = __register_trace_kprobe(tk);
 591         if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
 592                 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 593                 ret = 0;
 594         }
 595
 596         if (ret)
 597                 trace_probe_unlink(&tk->tp);
 598         else
 599                 dyn_event_add(&tk->devent);
 600
 601         return ret;
 602 }
 603
 604 /* Register a trace_probe and probe_event */
 605 static int register_trace_kprobe(struct trace_kprobe *tk)
 606 {
 607         struct trace_kprobe *old_tk;
 608         int ret;
 609
 610         mutex_lock(&event_mutex);
 611
 612         old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
 613                                    trace_probe_group_name(&tk->tp));
 614         if (old_tk) {
 615                 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
 616                         trace_probe_log_set_index(0);
 617                         trace_probe_log_err(0, DIFF_PROBE_TYPE);
 618                         ret = -EEXIST;
 619                 } else {
 620                         ret = append_trace_kprobe(tk, old_tk);
 621                 }
 622                 goto end;
 623         }
 624
 625         /* Register new event */
 626         ret = register_kprobe_event(tk);
 627         if (ret) {
 628                 pr_warn("Failed to register probe event(%d)\n", ret);
 629                 goto end;
 630         }
 631
 632         /* Register k*probe */
 633         ret = __register_trace_kprobe(tk);
 634         if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
 635                 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 636                 ret = 0;
 637         }
 638
 639         if (ret < 0)
 640                 unregister_kprobe_event(tk);
 641         else
 642                 dyn_event_add(&tk->devent);
 643
 644 end:
 645         mutex_unlock(&event_mutex);
 646         return ret;
 647 }
 648
 649 /* Module notifier call back, checking event on the module */
 650 static int trace_kprobe_module_callback(struct notifier_block *nb,
 651                                        unsigned long val, void *data)
 652 {
 653         struct module *mod = data;
 654         struct dyn_event *pos;
 655         struct trace_kprobe *tk;
 656         int ret;
 657
 658         if (val != MODULE_STATE_COMING)
 659                 return NOTIFY_DONE;
 660
 661         /* Update probes on coming module */
 662         mutex_lock(&event_mutex);
 663         for_each_trace_kprobe(tk, pos) {
 664                 if (trace_kprobe_within_module(tk, mod)) {
 665                         /* Don't need to check busy - this should have gone. */
 666                         __unregister_trace_kprobe(tk);
 667                         ret = __register_trace_kprobe(tk);
 668                         if (ret)
 669                                 pr_warn("Failed to re-register probe %s on %s: %d\n",
 670                                         trace_probe_name(&tk->tp),
 671                                         mod->name, ret);
 672                 }
 673         }
 674         mutex_unlock(&event_mutex);
 675
 676         return NOTIFY_DONE;
 677 }
 678
 679 static struct notifier_block trace_kprobe_module_nb = {
 680         .notifier_call = trace_kprobe_module_callback,
 681         .priority = 1   /* Invoked after kprobe module callback */
 682 };
 683
 684 /* Convert certain expected symbols into '_' when generating event names */
 685 static inline void sanitize_event_name(char *name)
 686 {
 687         while (*name++ != '\0')
 688                 if (*name == ':' || *name == '.')
 689                         *name = '_';
 690 }
 691
 692 static int trace_kprobe_create(int argc, const char *argv[])
 693 {
 694         /*
 695          * Argument syntax:
 696          *  - Add kprobe:
 697          *      p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 698          *  - Add kretprobe:
 699          *      r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
 700          * Fetch args:
 701          *  $retval     : fetch return value
 702          *  $stack      : fetch stack address
 703          *  $stackN     : fetch Nth of stack (N:0-)
 704          *  $comm       : fetch current task comm
 705          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 706          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 707          *  %REG        : fetch register REG
 708          * Dereferencing memory fetch:
 709          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 710          * Alias name of args:
 711          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 712          * Type of args:
 713          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 714          */
 715         struct trace_kprobe *tk = NULL;
 716         int i, len, ret = 0;
 717         bool is_return = false;
 718         char *symbol = NULL, *tmp = NULL;
 719         const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
 720         int maxactive = 0;
 721         long offset = 0;
 722         void *addr = NULL;
 723         char buf[MAX_EVENT_NAME_LEN];
 724         unsigned int flags = TPARG_FL_KERNEL;
 725
 726         switch (argv[0][0]) {
 727         case 'r':
 728                 is_return = true;
 729                 flags |= TPARG_FL_RETURN;
 730                 break;
 731         case 'p':
 732                 break;
 733         default:
 734                 return -ECANCELED;
 735         }
 736         if (argc < 2)
 737                 return -ECANCELED;
 738
 739         trace_probe_log_init("trace_kprobe", argc, argv);
 740
 741         event = strchr(&argv[0][1], ':');
 742         if (event)
 743                 event++;
 744
 745         if (isdigit(argv[0][1])) {
 746                 if (!is_return) {
 747                         trace_probe_log_err(1, MAXACT_NO_KPROBE);
 748                         goto parse_error;
 749                 }
 750                 if (event)
 751                         len = event - &argv[0][1] - 1;
 752                 else
 753                         len = strlen(&argv[0][1]);
 754                 if (len > MAX_EVENT_NAME_LEN - 1) {
 755                         trace_probe_log_err(1, BAD_MAXACT);
 756                         goto parse_error;
 757                 }
 758                 memcpy(buf, &argv[0][1], len);
 759                 buf[len] = '\0';
 760                 ret = kstrtouint(buf, 0, &maxactive);
 761                 if (ret || !maxactive) {
 762                         trace_probe_log_err(1, BAD_MAXACT);
 763                         goto parse_error;
 764                 }
 765                 /* kretprobes instances are iterated over via a list. The
 766                  * maximum should stay reasonable.
 767                  */
 768                 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
 769                         trace_probe_log_err(1, MAXACT_TOO_BIG);
 770                         goto parse_error;
 771                 }
 772         }
 773
 774         /* try to parse an address. if that fails, try to read the
 775          * input as a symbol. */
 776         if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
 777                 trace_probe_log_set_index(1);
 778                 /* Check whether uprobe event specified */
 779                 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
 780                         ret = -ECANCELED;
 781                         goto error;
 782                 }
 783                 /* a symbol specified */
 784                 symbol = kstrdup(argv[1], GFP_KERNEL);
 785                 if (!symbol)
 786                         return -ENOMEM;
 787                 /* TODO: support .init module functions */
 788                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 789                 if (ret || offset < 0 || offset > UINT_MAX) {
 790                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 791                         goto parse_error;
 792                 }
 793                 if (kprobe_on_func_entry(NULL, symbol, offset))
 794                         flags |= TPARG_FL_FENTRY;
 795                 if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {
 796                         trace_probe_log_err(0, BAD_RETPROBE);
 797                         goto parse_error;
 798                 }
 799         }
 800
 801         trace_probe_log_set_index(0);
 802         if (event) {
 803                 ret = traceprobe_parse_event_name(&event, &group, buf,
 804                                                   event - argv[0]);
 805                 if (ret)
 806                         goto parse_error;
 807         } else {
 808                 /* Make a new event name */
 809                 if (symbol)
 810                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 811                                  is_return ? 'r' : 'p', symbol, offset);
 812                 else
 813                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 814                                  is_return ? 'r' : 'p', addr);
 815                 sanitize_event_name(buf);
 816                 event = buf;
 817         }
 818
 819         /* setup a probe */
 820         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
 821                                argc - 2, is_return);
 822         if (IS_ERR(tk)) {
 823                 ret = PTR_ERR(tk);
 824                 /* This must return -ENOMEM, else there is a bug */
 825                 WARN_ON_ONCE(ret != -ENOMEM);
 826                 goto out;       /* We know tk is not allocated */
 827         }
 828         argc -= 2; argv += 2;
 829
 830         /* parse arguments */
 831         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 832                 tmp = kstrdup(argv[i], GFP_KERNEL);
 833                 if (!tmp) {
 834                         ret = -ENOMEM;
 835                         goto error;
 836                 }
 837
 838                 trace_probe_log_set_index(i + 2);
 839                 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
 840                 kfree(tmp);
 841                 if (ret)
 842                         goto error;     /* This can be -ENOMEM */
 843         }
 844
 845         ret = traceprobe_set_print_fmt(&tk->tp, is_return);
 846         if (ret < 0)
 847                 goto error;
 848
 849         ret = register_trace_kprobe(tk);
 850         if (ret) {
 851                 trace_probe_log_set_index(1);
 852                 if (ret == -EILSEQ)
 853                         trace_probe_log_err(0, BAD_INSN_BNDRY);
 854                 else if (ret == -ENOENT)
 855                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 856                 else if (ret != -ENOMEM && ret != -EEXIST)
 857                         trace_probe_log_err(0, FAIL_REG_PROBE);
 858                 goto error;
 859         }
 860
 861 out:
 862         trace_probe_log_clear();
 863         kfree(symbol);
 864         return ret;
 865
 866 parse_error:
 867         ret = -EINVAL;
 868 error:
 869         free_trace_kprobe(tk);
 870         goto out;
 871 }
 872
 873 static int create_or_delete_trace_kprobe(int argc, char **argv)
 874 {
 875         int ret;
 876
 877         if (argv[0][0] == '-')
 878                 return dyn_event_release(argc, argv, &trace_kprobe_ops);
 879
 880         ret = trace_kprobe_create(argc, (const char **)argv);
 881         return ret == -ECANCELED ? -EINVAL : ret;
 882 }
 883
 884 static int trace_kprobe_release(struct dyn_event *ev)
 885 {
 886         struct trace_kprobe *tk = to_trace_kprobe(ev);
 887         int ret = unregister_trace_kprobe(tk);
 888
 889         if (!ret)
 890                 free_trace_kprobe(tk);
 891         return ret;
 892 }
 893
 894 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
 895 {
 896         struct trace_kprobe *tk = to_trace_kprobe(ev);
 897         int i;
 898
 899         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
 900         seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
 901                                 trace_probe_name(&tk->tp));
 902
 903         if (!tk->symbol)
 904                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
 905         else if (tk->rp.kp.offset)
 906                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
 907                            tk->rp.kp.offset);
 908         else
 909                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
 910
 911         for (i = 0; i < tk->tp.nr_args; i++)
 912                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
 913         seq_putc(m, '\n');
 914
 915         return 0;
 916 }
 917
 918 static int probes_seq_show(struct seq_file *m, void *v)
 919 {
 920         struct dyn_event *ev = v;
 921
 922         if (!is_trace_kprobe(ev))
 923                 return 0;
 924
 925         return trace_kprobe_show(m, ev);
 926 }
 927
 928 static const struct seq_operations probes_seq_op = {
 929         .start  = dyn_event_seq_start,
 930         .next   = dyn_event_seq_next,
 931         .stop   = dyn_event_seq_stop,
 932         .show   = probes_seq_show
 933 };
 934
 935 static int probes_open(struct inode *inode, struct file *file)
 936 {
 937         int ret;
 938
 939         ret = security_locked_down(LOCKDOWN_TRACEFS);
 940         if (ret)
 941                 return ret;
 942
 943         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 944                 ret = dyn_events_release_all(&trace_kprobe_ops);
 945                 if (ret < 0)
 946                         return ret;
 947         }
 948
 949         return seq_open(file, &probes_seq_op);
 950 }
 951
 952 static ssize_t probes_write(struct file *file, const char __user *buffer,
 953                             size_t count, loff_t *ppos)
 954 {
 955         return trace_parse_run_command(file, buffer, count, ppos,
 956                                        create_or_delete_trace_kprobe);
 957 }
 958
 959 static const struct file_operations kprobe_events_ops = {
 960         .owner          = THIS_MODULE,
 961         .open           = probes_open,
 962         .read           = seq_read,
 963         .llseek         = seq_lseek,
 964         .release        = seq_release,
 965         .write          = probes_write,
 966 };
 967
 968 /* Probes profiling interfaces */
 969 static int probes_profile_seq_show(struct seq_file *m, void *v)
 970 {
 971         struct dyn_event *ev = v;
 972         struct trace_kprobe *tk;
 973
 974         if (!is_trace_kprobe(ev))
 975                 return 0;
 976
 977         tk = to_trace_kprobe(ev);
 978         seq_printf(m, "  %-44s %15lu %15lu\n",
 979                    trace_probe_name(&tk->tp),
 980                    trace_kprobe_nhit(tk),
 981                    tk->rp.kp.nmissed);
 982
 983         return 0;
 984 }
 985
 986 static const struct seq_operations profile_seq_op = {
 987         .start  = dyn_event_seq_start,
 988         .next   = dyn_event_seq_next,
 989         .stop   = dyn_event_seq_stop,
 990         .show   = probes_profile_seq_show
 991 };
 992
 993 static int profile_open(struct inode *inode, struct file *file)
 994 {
 995         int ret;
 996
 997         ret = security_locked_down(LOCKDOWN_TRACEFS);
 998         if (ret)
 999                 return ret;
1000
1001         return seq_open(file, &profile_seq_op);
1002 }
1003
1004 static const struct file_operations kprobe_profile_ops = {
1005         .owner          = THIS_MODULE,
1006         .open           = profile_open,
1007         .read           = seq_read,
1008         .llseek         = seq_lseek,
1009         .release        = seq_release,
1010 };
1011
1012 /* Kprobe specific fetch functions */
1013
1014 /* Return the length of string -- including null terminal byte */
1015 static nokprobe_inline int
1016 fetch_store_strlen(unsigned long addr)
1017 {
1018         int ret, len = 0;
1019         u8 c;
1020
1021         do {
1022                 ret = probe_kernel_read(&c, (u8 *)addr + len, 1);
1023                 len++;
1024         } while (c && ret == 0 && len < MAX_STRING_SIZE);
1025
1026         return (ret < 0) ? ret : len;
1027 }
1028
1029 /* Return the length of string -- including null terminal byte */
1030 static nokprobe_inline int
1031 fetch_store_strlen_user(unsigned long addr)
1032 {
1033         const void __user *uaddr =  (__force const void __user *)addr;
1034
1035         return strnlen_unsafe_user(uaddr, MAX_STRING_SIZE);
1036 }
1037
1038 /*
1039  * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
1040  * length and relative data location.
1041  */
1042 static nokprobe_inline int
1043 fetch_store_string(unsigned long addr, void *dest, void *base)
1044 {
1045         int maxlen = get_loc_len(*(u32 *)dest);
1046         void *__dest;
1047         long ret;
1048
1049         if (unlikely(!maxlen))
1050                 return -ENOMEM;
1051
1052         __dest = get_loc_data(dest, base);
1053
1054         /*
1055          * Try to get string again, since the string can be changed while
1056          * probing.
1057          */
1058         ret = strncpy_from_unsafe(__dest, (void *)addr, maxlen);
1059         if (ret >= 0)
1060                 *(u32 *)dest = make_data_loc(ret, __dest - base);
1061
1062         return ret;
1063 }
1064
1065 /*
1066  * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
1067  * with max length and relative data location.
1068  */
1069 static nokprobe_inline int
1070 fetch_store_string_user(unsigned long addr, void *dest, void *base)
1071 {
1072         const void __user *uaddr =  (__force const void __user *)addr;
1073         int maxlen = get_loc_len(*(u32 *)dest);
1074         void *__dest;
1075         long ret;
1076
1077         if (unlikely(!maxlen))
1078                 return -ENOMEM;
1079
1080         __dest = get_loc_data(dest, base);
1081
1082         ret = strncpy_from_unsafe_user(__dest, uaddr, maxlen);
1083         if (ret >= 0)
1084                 *(u32 *)dest = make_data_loc(ret, __dest - base);
1085
1086         return ret;
1087 }
1088
1089 static nokprobe_inline int
1090 probe_mem_read(void *dest, void *src, size_t size)
1091 {
1092         return probe_kernel_read(dest, src, size);
1093 }
1094
1095 static nokprobe_inline int
1096 probe_mem_read_user(void *dest, void *src, size_t size)
1097 {
1098         const void __user *uaddr =  (__force const void __user *)src;
1099
1100         return probe_user_read(dest, uaddr, size);
1101 }
1102
1103 /* Note that we don't verify it, since the code does not come from user space */
1104 static int
1105 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
1106                    void *base)
1107 {
1108         unsigned long val;
1109
1110 retry:
1111         /* 1st stage: get value from context */
1112         switch (code->op) {
1113         case FETCH_OP_REG:
1114                 val = regs_get_register(regs, code->param);
1115                 break;
1116         case FETCH_OP_STACK:
1117                 val = regs_get_kernel_stack_nth(regs, code->param);
1118                 break;
1119         case FETCH_OP_STACKP:
1120                 val = kernel_stack_pointer(regs);
1121                 break;
1122         case FETCH_OP_RETVAL:
1123                 val = regs_return_value(regs);
1124                 break;
1125         case FETCH_OP_IMM:
1126                 val = code->immediate;
1127                 break;
1128         case FETCH_OP_COMM:
1129                 val = (unsigned long)current->comm;
1130                 break;
1131         case FETCH_OP_DATA:
1132                 val = (unsigned long)code->data;
1133                 break;
1134 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1135         case FETCH_OP_ARG:
1136                 val = regs_get_kernel_argument(regs, code->param);
1137                 break;
1138 #endif
1139         case FETCH_NOP_SYMBOL:  /* Ignore a place holder */
1140                 code++;
1141                 goto retry;
1142         default:
1143                 return -EILSEQ;
1144         }
1145         code++;
1146
1147         return process_fetch_insn_bottom(code, val, dest, base);
1148 }
1149 NOKPROBE_SYMBOL(process_fetch_insn)
1150
1151 /* Kprobe handler */
1152 static nokprobe_inline void
1153 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1154                     struct trace_event_file *trace_file)
1155 {
1156         struct kprobe_trace_entry_head *entry;
1157         struct ring_buffer_event *event;
1158         struct ring_buffer *buffer;
1159         int size, dsize, pc;
1160         unsigned long irq_flags;
1161         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1162
1163         WARN_ON(call != trace_file->event_call);
1164
1165         if (trace_trigger_soft_disabled(trace_file))
1166                 return;
1167
1168         local_save_flags(irq_flags);
1169         pc = preempt_count();
1170
1171         dsize = __get_data_size(&tk->tp, regs);
1172         size = sizeof(*entry) + tk->tp.size + dsize;
1173
1174         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1175                                                 call->event.type,
1176                                                 size, irq_flags, pc);
1177         if (!event)
1178                 return;
1179
1180         entry = ring_buffer_event_data(event);
1181         entry->ip = (unsigned long)tk->rp.kp.addr;
1182         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1183
1184         event_trigger_unlock_commit_regs(trace_file, buffer, event,
1185                                          entry, irq_flags, pc, regs);
1186 }
1187
1188 static void
1189 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1190 {
1191         struct event_file_link *link;
1192
1193         trace_probe_for_each_link_rcu(link, &tk->tp)
1194                 __kprobe_trace_func(tk, regs, link->file);
1195 }
1196 NOKPROBE_SYMBOL(kprobe_trace_func);
1197
1198 /* Kretprobe handler */
1199 static nokprobe_inline void
1200 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1201                        struct pt_regs *regs,
1202                        struct trace_event_file *trace_file)
1203 {
1204         struct kretprobe_trace_entry_head *entry;
1205         struct ring_buffer_event *event;
1206         struct ring_buffer *buffer;
1207         int size, pc, dsize;
1208         unsigned long irq_flags;
1209         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1210
1211         WARN_ON(call != trace_file->event_call);
1212
1213         if (trace_trigger_soft_disabled(trace_file))
1214                 return;
1215
1216         local_save_flags(irq_flags);
1217         pc = preempt_count();
1218
1219         dsize = __get_data_size(&tk->tp, regs);
1220         size = sizeof(*entry) + tk->tp.size + dsize;
1221
1222         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1223                                                 call->event.type,
1224                                                 size, irq_flags, pc);
1225         if (!event)
1226                 return;
1227
1228         entry = ring_buffer_event_data(event);
1229         entry->func = (unsigned long)tk->rp.kp.addr;
1230         entry->ret_ip = (unsigned long)ri->ret_addr;
1231         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1232
1233         event_trigger_unlock_commit_regs(trace_file, buffer, event,
1234                                          entry, irq_flags, pc, regs);
1235 }
1236
1237 static void
1238 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1239                      struct pt_regs *regs)
1240 {
1241         struct event_file_link *link;
1242
1243         trace_probe_for_each_link_rcu(link, &tk->tp)
1244                 __kretprobe_trace_func(tk, ri, regs, link->file);
1245 }
1246 NOKPROBE_SYMBOL(kretprobe_trace_func);
1247
1248 /* Event entry printers */
1249 static enum print_line_t
1250 print_kprobe_event(struct trace_iterator *iter, int flags,
1251                    struct trace_event *event)
1252 {
1253         struct kprobe_trace_entry_head *field;
1254         struct trace_seq *s = &iter->seq;
1255         struct trace_probe *tp;
1256
1257         field = (struct kprobe_trace_entry_head *)iter->ent;
1258         tp = trace_probe_primary_from_call(
1259                 container_of(event, struct trace_event_call, event));
1260         if (WARN_ON_ONCE(!tp))
1261                 goto out;
1262
1263         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1264
1265         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1266                 goto out;
1267
1268         trace_seq_putc(s, ')');
1269
1270         if (print_probe_args(s, tp->args, tp->nr_args,
1271                              (u8 *)&field[1], field) < 0)
1272                 goto out;
1273
1274         trace_seq_putc(s, '\n');
1275  out:
1276         return trace_handle_return(s);
1277 }
1278
1279 static enum print_line_t
1280 print_kretprobe_event(struct trace_iterator *iter, int flags,
1281                       struct trace_event *event)
1282 {
1283         struct kretprobe_trace_entry_head *field;
1284         struct trace_seq *s = &iter->seq;
1285         struct trace_probe *tp;
1286
1287         field = (struct kretprobe_trace_entry_head *)iter->ent;
1288         tp = trace_probe_primary_from_call(
1289                 container_of(event, struct trace_event_call, event));
1290         if (WARN_ON_ONCE(!tp))
1291                 goto out;
1292
1293         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1294
1295         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1296                 goto out;
1297
1298         trace_seq_puts(s, " <- ");
1299
1300         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1301                 goto out;
1302
1303         trace_seq_putc(s, ')');
1304
1305         if (print_probe_args(s, tp->args, tp->nr_args,
1306                              (u8 *)&field[1], field) < 0)
1307                 goto out;
1308
1309         trace_seq_putc(s, '\n');
1310
1311  out:
1312         return trace_handle_return(s);
1313 }
1314
1315
1316 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1317 {
1318         int ret;
1319         struct kprobe_trace_entry_head field;
1320         struct trace_probe *tp;
1321
1322         tp = trace_probe_primary_from_call(event_call);
1323         if (WARN_ON_ONCE(!tp))
1324                 return -ENOENT;
1325
1326         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1327
1328         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1329 }
1330
1331 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1332 {
1333         int ret;
1334         struct kretprobe_trace_entry_head field;
1335         struct trace_probe *tp;
1336
1337         tp = trace_probe_primary_from_call(event_call);
1338         if (WARN_ON_ONCE(!tp))
1339                 return -ENOENT;
1340
1341         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1342         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1343
1344         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1345 }
1346
1347 #ifdef CONFIG_PERF_EVENTS
1348
1349 /* Kprobe profile handler */
1350 static int
1351 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1352 {
1353         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1354         struct kprobe_trace_entry_head *entry;
1355         struct hlist_head *head;
1356         int size, __size, dsize;
1357         int rctx;
1358
1359         if (bpf_prog_array_valid(call)) {
1360                 unsigned long orig_ip = instruction_pointer(regs);
1361                 int ret;
1362
1363                 ret = trace_call_bpf(call, regs);
1364
1365                 /*
1366                  * We need to check and see if we modified the pc of the
1367                  * pt_regs, and if so return 1 so that we don't do the
1368                  * single stepping.
1369                  */
1370                 if (orig_ip != instruction_pointer(regs))
1371                         return 1;
1372                 if (!ret)
1373                         return 0;
1374         }
1375
1376         head = this_cpu_ptr(call->perf_events);
1377         if (hlist_empty(head))
1378                 return 0;
1379
1380         dsize = __get_data_size(&tk->tp, regs);
1381         __size = sizeof(*entry) + tk->tp.size + dsize;
1382         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1383         size -= sizeof(u32);
1384
1385         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1386         if (!entry)
1387                 return 0;
1388
1389         entry->ip = (unsigned long)tk->rp.kp.addr;
1390         memset(&entry[1], 0, dsize);
1391         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1392         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1393                               head, NULL);
1394         return 0;
1395 }
1396 NOKPROBE_SYMBOL(kprobe_perf_func);
1397
1398 /* Kretprobe profile handler */
1399 static void
1400 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1401                     struct pt_regs *regs)
1402 {
1403         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1404         struct kretprobe_trace_entry_head *entry;
1405         struct hlist_head *head;
1406         int size, __size, dsize;
1407         int rctx;
1408
1409         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1410                 return;
1411
1412         head = this_cpu_ptr(call->perf_events);
1413         if (hlist_empty(head))
1414                 return;
1415
1416         dsize = __get_data_size(&tk->tp, regs);
1417         __size = sizeof(*entry) + tk->tp.size + dsize;
1418         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1419         size -= sizeof(u32);
1420
1421         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1422         if (!entry)
1423                 return;
1424
1425         entry->func = (unsigned long)tk->rp.kp.addr;
1426         entry->ret_ip = (unsigned long)ri->ret_addr;
1427         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1428         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1429                               head, NULL);
1430 }
1431 NOKPROBE_SYMBOL(kretprobe_perf_func);
1432
1433 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1434                         const char **symbol, u64 *probe_offset,
1435                         u64 *probe_addr, bool perf_type_tracepoint)
1436 {
1437         const char *pevent = trace_event_name(event->tp_event);
1438         const char *group = event->tp_event->class->system;
1439         struct trace_kprobe *tk;
1440
1441         if (perf_type_tracepoint)
1442                 tk = find_trace_kprobe(pevent, group);
1443         else
1444                 tk = event->tp_event->data;
1445         if (!tk)
1446                 return -EINVAL;
1447
1448         *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1449                                               : BPF_FD_TYPE_KPROBE;
1450         if (tk->symbol) {
1451                 *symbol = tk->symbol;
1452                 *probe_offset = tk->rp.kp.offset;
1453                 *probe_addr = 0;
1454         } else {
1455                 *symbol = NULL;
1456                 *probe_offset = 0;
1457                 *probe_addr = (unsigned long)tk->rp.kp.addr;
1458         }
1459         return 0;
1460 }
1461 #endif  /* CONFIG_PERF_EVENTS */
1462
1463 /*
1464  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1465  *
1466  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1467  * lockless, but we can't race with this __init function.
1468  */
1469 static int kprobe_register(struct trace_event_call *event,
1470                            enum trace_reg type, void *data)
1471 {
1472         struct trace_event_file *file = data;
1473
1474         switch (type) {
1475         case TRACE_REG_REGISTER:
1476                 return enable_trace_kprobe(event, file);
1477         case TRACE_REG_UNREGISTER:
1478                 return disable_trace_kprobe(event, file);
1479
1480 #ifdef CONFIG_PERF_EVENTS
1481         case TRACE_REG_PERF_REGISTER:
1482                 return enable_trace_kprobe(event, NULL);
1483         case TRACE_REG_PERF_UNREGISTER:
1484                 return disable_trace_kprobe(event, NULL);
1485         case TRACE_REG_PERF_OPEN:
1486         case TRACE_REG_PERF_CLOSE:
1487         case TRACE_REG_PERF_ADD:
1488         case TRACE_REG_PERF_DEL:
1489                 return 0;
1490 #endif
1491         }
1492         return 0;
1493 }
1494
1495 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1496 {
1497         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1498         int ret = 0;
1499
1500         raw_cpu_inc(*tk->nhit);
1501
1502         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1503                 kprobe_trace_func(tk, regs);
1504 #ifdef CONFIG_PERF_EVENTS
1505         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1506                 ret = kprobe_perf_func(tk, regs);
1507 #endif
1508         return ret;
1509 }
1510 NOKPROBE_SYMBOL(kprobe_dispatcher);
1511
1512 static int
1513 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1514 {
1515         struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1516
1517         raw_cpu_inc(*tk->nhit);
1518
1519         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1520                 kretprobe_trace_func(tk, ri, regs);
1521 #ifdef CONFIG_PERF_EVENTS
1522         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1523                 kretprobe_perf_func(tk, ri, regs);
1524 #endif
1525         return 0;       /* We don't tweek kernel, so just return 0 */
1526 }
1527 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1528
1529 static struct trace_event_functions kretprobe_funcs = {
1530         .trace          = print_kretprobe_event
1531 };
1532
1533 static struct trace_event_functions kprobe_funcs = {
1534         .trace          = print_kprobe_event
1535 };
1536
1537 static inline void init_trace_event_call(struct trace_kprobe *tk)
1538 {
1539         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1540
1541         if (trace_kprobe_is_return(tk)) {
1542                 call->event.funcs = &kretprobe_funcs;
1543                 call->class->define_fields = kretprobe_event_define_fields;
1544         } else {
1545                 call->event.funcs = &kprobe_funcs;
1546                 call->class->define_fields = kprobe_event_define_fields;
1547         }
1548
1549         call->flags = TRACE_EVENT_FL_KPROBE;
1550         call->class->reg = kprobe_register;
1551 }
1552
1553 static int register_kprobe_event(struct trace_kprobe *tk)
1554 {
1555         init_trace_event_call(tk);
1556
1557         return trace_probe_register_event_call(&tk->tp);
1558 }
1559
1560 static int unregister_kprobe_event(struct trace_kprobe *tk)
1561 {
1562         return trace_probe_unregister_event_call(&tk->tp);
1563 }
1564
1565 #ifdef CONFIG_PERF_EVENTS
1566 /* create a trace_kprobe, but don't add it to global lists */
1567 struct trace_event_call *
1568 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1569                           bool is_return)
1570 {
1571         struct trace_kprobe *tk;
1572         int ret;
1573         char *event;
1574
1575         /*
1576          * local trace_kprobes are not added to dyn_event, so they are never
1577          * searched in find_trace_kprobe(). Therefore, there is no concern of
1578          * duplicated name here.
1579          */
1580         event = func ? func : "DUMMY_EVENT";
1581
1582         tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1583                                 offs, 0 /* maxactive */, 0 /* nargs */,
1584                                 is_return);
1585
1586         if (IS_ERR(tk)) {
1587                 pr_info("Failed to allocate trace_probe.(%d)\n",
1588                         (int)PTR_ERR(tk));
1589                 return ERR_CAST(tk);
1590         }
1591
1592         init_trace_event_call(tk);
1593
1594         if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1595                 ret = -ENOMEM;
1596                 goto error;
1597         }
1598
1599         ret = __register_trace_kprobe(tk);
1600         if (ret < 0)
1601                 goto error;
1602
1603         return trace_probe_event_call(&tk->tp);
1604 error:
1605         free_trace_kprobe(tk);
1606         return ERR_PTR(ret);
1607 }
1608
1609 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1610 {
1611         struct trace_kprobe *tk;
1612
1613         tk = trace_kprobe_primary_from_call(event_call);
1614         if (unlikely(!tk))
1615                 return;
1616
1617         if (trace_probe_is_enabled(&tk->tp)) {
1618                 WARN_ON(1);
1619                 return;
1620         }
1621
1622         __unregister_trace_kprobe(tk);
1623
1624         free_trace_kprobe(tk);
1625 }
1626 #endif /* CONFIG_PERF_EVENTS */
1627
1628 static __init void enable_boot_kprobe_events(void)
1629 {
1630         struct trace_array *tr = top_trace_array();
1631         struct trace_event_file *file;
1632         struct trace_kprobe *tk;
1633         struct dyn_event *pos;
1634
1635         mutex_lock(&event_mutex);
1636         for_each_trace_kprobe(tk, pos) {
1637                 list_for_each_entry(file, &tr->events, list)
1638                         if (file->event_call == trace_probe_event_call(&tk->tp))
1639                                 trace_event_enable_disable(file, 1, 0);
1640         }
1641         mutex_unlock(&event_mutex);
1642 }
1643
1644 static __init void setup_boot_kprobe_events(void)
1645 {
1646         char *p, *cmd = kprobe_boot_events_buf;
1647         int ret;
1648
1649         strreplace(kprobe_boot_events_buf, ',', ' ');
1650
1651         while (cmd && *cmd != '\0') {
1652                 p = strchr(cmd, ';');
1653                 if (p)
1654                         *p++ = '\0';
1655
1656                 ret = trace_run_command(cmd, create_or_delete_trace_kprobe);
1657                 if (ret)
1658                         pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1659                 else
1660                         kprobe_boot_events_enabled = true;
1661
1662                 cmd = p;
1663         }
1664
1665         enable_boot_kprobe_events();
1666 }
1667
1668 /* Make a tracefs interface for controlling probe points */
1669 static __init int init_kprobe_trace(void)
1670 {
1671         struct dentry *d_tracer;
1672         struct dentry *entry;
1673         int ret;
1674
1675         ret = dyn_event_register(&trace_kprobe_ops);
1676         if (ret)
1677                 return ret;
1678
1679         if (register_module_notifier(&trace_kprobe_module_nb))
1680                 return -EINVAL;
1681
1682         d_tracer = tracing_init_dentry();
1683         if (IS_ERR(d_tracer))
1684                 return 0;
1685
1686         entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1687                                     NULL, &kprobe_events_ops);
1688
1689         /* Event list interface */
1690         if (!entry)
1691                 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1692
1693         /* Profile interface */
1694         entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1695                                     NULL, &kprobe_profile_ops);
1696
1697         if (!entry)
1698                 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1699
1700         setup_boot_kprobe_events();
1701
1702         return 0;
1703 }
1704 fs_initcall(init_kprobe_trace);
1705
1706
1707 #ifdef CONFIG_FTRACE_STARTUP_TEST
1708 static __init struct trace_event_file *
1709 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1710 {
1711         struct trace_event_file *file;
1712
1713         list_for_each_entry(file, &tr->events, list)
1714                 if (file->event_call == trace_probe_event_call(&tk->tp))
1715                         return file;
1716
1717         return NULL;
1718 }
1719
1720 /*
1721  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1722  * stage, we can do this lockless.
1723  */
1724 static __init int kprobe_trace_self_tests_init(void)
1725 {
1726         int ret, warn = 0;
1727         int (*target)(int, int, int, int, int, int);
1728         struct trace_kprobe *tk;
1729         struct trace_event_file *file;
1730
1731         if (tracing_is_disabled())
1732                 return -ENODEV;
1733
1734         if (kprobe_boot_events_enabled) {
1735                 pr_info("Skipping kprobe tests due to kprobe_event on cmdline\n");
1736                 return 0;
1737         }
1738
1739         target = kprobe_trace_selftest_target;
1740
1741         pr_info("Testing kprobe tracing: ");
1742
1743         ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)",
1744                                 create_or_delete_trace_kprobe);
1745         if (WARN_ON_ONCE(ret)) {
1746                 pr_warn("error on probing function entry.\n");
1747                 warn++;
1748         } else {
1749                 /* Enable trace point */
1750                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1751                 if (WARN_ON_ONCE(tk == NULL)) {
1752                         pr_warn("error on getting new probe.\n");
1753                         warn++;
1754                 } else {
1755                         file = find_trace_probe_file(tk, top_trace_array());
1756                         if (WARN_ON_ONCE(file == NULL)) {
1757                                 pr_warn("error on getting probe file.\n");
1758                                 warn++;
1759                         } else
1760                                 enable_trace_kprobe(
1761                                         trace_probe_event_call(&tk->tp), file);
1762                 }
1763         }
1764
1765         ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval",
1766                                 create_or_delete_trace_kprobe);
1767         if (WARN_ON_ONCE(ret)) {
1768                 pr_warn("error on probing function return.\n");
1769                 warn++;
1770         } else {
1771                 /* Enable trace point */
1772                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1773                 if (WARN_ON_ONCE(tk == NULL)) {
1774                         pr_warn("error on getting 2nd new probe.\n");
1775                         warn++;
1776                 } else {
1777                         file = find_trace_probe_file(tk, top_trace_array());
1778                         if (WARN_ON_ONCE(file == NULL)) {
1779                                 pr_warn("error on getting probe file.\n");
1780                                 warn++;
1781                         } else
1782                                 enable_trace_kprobe(
1783                                         trace_probe_event_call(&tk->tp), file);
1784                 }
1785         }
1786
1787         if (warn)
1788                 goto end;
1789
1790         ret = target(1, 2, 3, 4, 5, 6);
1791
1792         /*
1793          * Not expecting an error here, the check is only to prevent the
1794          * optimizer from removing the call to target() as otherwise there
1795          * are no side-effects and the call is never performed.
1796          */
1797         if (ret != 21)
1798                 warn++;
1799
1800         /* Disable trace points before removing it */
1801         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1802         if (WARN_ON_ONCE(tk == NULL)) {
1803                 pr_warn("error on getting test probe.\n");
1804                 warn++;
1805         } else {
1806                 if (trace_kprobe_nhit(tk) != 1) {
1807                         pr_warn("incorrect number of testprobe hits\n");
1808                         warn++;
1809                 }
1810
1811                 file = find_trace_probe_file(tk, top_trace_array());
1812                 if (WARN_ON_ONCE(file == NULL)) {
1813                         pr_warn("error on getting probe file.\n");
1814                         warn++;
1815                 } else
1816                         disable_trace_kprobe(
1817                                 trace_probe_event_call(&tk->tp), file);
1818         }
1819
1820         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1821         if (WARN_ON_ONCE(tk == NULL)) {
1822                 pr_warn("error on getting 2nd test probe.\n");
1823                 warn++;
1824         } else {
1825                 if (trace_kprobe_nhit(tk) != 1) {
1826                         pr_warn("incorrect number of testprobe2 hits\n");
1827                         warn++;
1828                 }
1829
1830                 file = find_trace_probe_file(tk, top_trace_array());
1831                 if (WARN_ON_ONCE(file == NULL)) {
1832                         pr_warn("error on getting probe file.\n");
1833                         warn++;
1834                 } else
1835                         disable_trace_kprobe(
1836                                 trace_probe_event_call(&tk->tp), file);
1837         }
1838
1839         ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe);
1840         if (WARN_ON_ONCE(ret)) {
1841                 pr_warn("error on deleting a probe.\n");
1842                 warn++;
1843         }
1844
1845         ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe);
1846         if (WARN_ON_ONCE(ret)) {
1847                 pr_warn("error on deleting a probe.\n");
1848                 warn++;
1849         }
1850
1851 end:
1852         ret = dyn_events_release_all(&trace_kprobe_ops);
1853         if (WARN_ON_ONCE(ret)) {
1854                 pr_warn("error on cleaning up probes.\n");
1855                 warn++;
1856         }
1857         /*
1858          * Wait for the optimizer work to finish. Otherwise it might fiddle
1859          * with probes in already freed __init text.
1860          */
1861         wait_for_kprobe_optimizer();
1862         if (warn)
1863                 pr_cont("NG: Some tests are failed. Please check them.\n");
1864         else
1865                 pr_cont("OK\n");
1866         return 0;
1867 }
1868
1869 late_initcall(kprobe_trace_self_tests_init);
1870
1871 #endif