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/module.h>
  11 #include <linux/uaccess.h>
  12 #include <linux/rculist.h>
  13 #include <linux/error-injection.h>
  14
  15 #include "trace_dynevent.h"
  16 #include "trace_kprobe_selftest.h"
  17 #include "trace_probe.h"
  18 #include "trace_probe_tmpl.h"
  19
  20 #define KPROBE_EVENT_SYSTEM "kprobes"
  21 #define KRETPROBE_MAXACTIVE_MAX 4096
  22
  23 static int trace_kprobe_create(int argc, const char **argv);
  24 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
  25 static int trace_kprobe_release(struct dyn_event *ev);
  26 static bool trace_kprobe_is_busy(struct dyn_event *ev);
  27 static bool trace_kprobe_match(const char *system, const char *event,
  28                                struct dyn_event *ev);
  29
  30 static struct dyn_event_operations trace_kprobe_ops = {
  31         .create = trace_kprobe_create,
  32         .show = trace_kprobe_show,
  33         .is_busy = trace_kprobe_is_busy,
  34         .free = trace_kprobe_release,
  35         .match = trace_kprobe_match,
  36 };
  37
  38 /*
  39  * Kprobe event core functions
  40  */
  41 struct trace_kprobe {
  42         struct dyn_event        devent;
  43         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
  44         unsigned long __percpu *nhit;
  45         const char              *symbol;        /* symbol name */
  46         struct trace_probe      tp;
  47 };
  48
  49 static bool is_trace_kprobe(struct dyn_event *ev)
  50 {
  51         return ev->ops == &trace_kprobe_ops;
  52 }
  53
  54 static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
  55 {
  56         return container_of(ev, struct trace_kprobe, devent);
  57 }
  58
  59 /**
  60  * for_each_trace_kprobe - iterate over the trace_kprobe list
  61  * @pos:        the struct trace_kprobe * for each entry
  62  * @dpos:       the struct dyn_event * to use as a loop cursor
  63  */
  64 #define for_each_trace_kprobe(pos, dpos)        \
  65         for_each_dyn_event(dpos)                \
  66                 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
  67
  68 #define SIZEOF_TRACE_KPROBE(n)                          \
  69         (offsetof(struct trace_kprobe, tp.args) +       \
  70         (sizeof(struct probe_arg) * (n)))
  71
  72 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
  73 {
  74         return tk->rp.handler != NULL;
  75 }
  76
  77 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
  78 {
  79         return tk->symbol ? tk->symbol : "unknown";
  80 }
  81
  82 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
  83 {
  84         return tk->rp.kp.offset;
  85 }
  86
  87 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
  88 {
  89         return !!(kprobe_gone(&tk->rp.kp));
  90 }
  91
  92 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
  93                                                  struct module *mod)
  94 {
  95         int len = strlen(mod->name);
  96         const char *name = trace_kprobe_symbol(tk);
  97         return strncmp(mod->name, name, len) == 0 && name[len] == ':';
  98 }
  99
 100 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
 101 {
 102         char *p;
 103         bool ret;
 104
 105         if (!tk->symbol)
 106                 return false;
 107         p = strchr(tk->symbol, ':');
 108         if (!p)
 109                 return true;
 110         *p = '\0';
 111         mutex_lock(&module_mutex);
 112         ret = !!find_module(tk->symbol);
 113         mutex_unlock(&module_mutex);
 114         *p = ':';
 115
 116         return ret;
 117 }
 118
 119 static bool trace_kprobe_is_busy(struct dyn_event *ev)
 120 {
 121         struct trace_kprobe *tk = to_trace_kprobe(ev);
 122
 123         return trace_probe_is_enabled(&tk->tp);
 124 }
 125
 126 static bool trace_kprobe_match(const char *system, const char *event,
 127                                struct dyn_event *ev)
 128 {
 129         struct trace_kprobe *tk = to_trace_kprobe(ev);
 130
 131         return strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
 132             (!system || strcmp(tk->tp.call.class->system, system) == 0);
 133 }
 134
 135 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
 136 {
 137         unsigned long nhit = 0;
 138         int cpu;
 139
 140         for_each_possible_cpu(cpu)
 141                 nhit += *per_cpu_ptr(tk->nhit, cpu);
 142
 143         return nhit;
 144 }
 145
 146 /* Return 0 if it fails to find the symbol address */
 147 static nokprobe_inline
 148 unsigned long trace_kprobe_address(struct trace_kprobe *tk)
 149 {
 150         unsigned long addr;
 151
 152         if (tk->symbol) {
 153                 addr = (unsigned long)
 154                         kallsyms_lookup_name(trace_kprobe_symbol(tk));
 155                 if (addr)
 156                         addr += tk->rp.kp.offset;
 157         } else {
 158                 addr = (unsigned long)tk->rp.kp.addr;
 159         }
 160         return addr;
 161 }
 162
 163 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
 164 {
 165         struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
 166
 167         return kprobe_on_func_entry(tk->rp.kp.addr,
 168                         tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
 169                         tk->rp.kp.addr ? 0 : tk->rp.kp.offset);
 170 }
 171
 172 bool trace_kprobe_error_injectable(struct trace_event_call *call)
 173 {
 174         struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
 175
 176         return within_error_injection_list(trace_kprobe_address(tk));
 177 }
 178
 179 static int register_kprobe_event(struct trace_kprobe *tk);
 180 static int unregister_kprobe_event(struct trace_kprobe *tk);
 181
 182 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 183 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 184                                 struct pt_regs *regs);
 185
 186 /*
 187  * Allocate new trace_probe and initialize it (including kprobes).
 188  */
 189 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
 190                                              const char *event,
 191                                              void *addr,
 192                                              const char *symbol,
 193                                              unsigned long offs,
 194                                              int maxactive,
 195                                              int nargs, bool is_return)
 196 {
 197         struct trace_kprobe *tk;
 198         int ret = -ENOMEM;
 199
 200         tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
 201         if (!tk)
 202                 return ERR_PTR(ret);
 203
 204         tk->nhit = alloc_percpu(unsigned long);
 205         if (!tk->nhit)
 206                 goto error;
 207
 208         if (symbol) {
 209                 tk->symbol = kstrdup(symbol, GFP_KERNEL);
 210                 if (!tk->symbol)
 211                         goto error;
 212                 tk->rp.kp.symbol_name = tk->symbol;
 213                 tk->rp.kp.offset = offs;
 214         } else
 215                 tk->rp.kp.addr = addr;
 216
 217         if (is_return)
 218                 tk->rp.handler = kretprobe_dispatcher;
 219         else
 220                 tk->rp.kp.pre_handler = kprobe_dispatcher;
 221
 222         tk->rp.maxactive = maxactive;
 223
 224         if (!event || !group) {
 225                 ret = -EINVAL;
 226                 goto error;
 227         }
 228
 229         tk->tp.call.class = &tk->tp.class;
 230         tk->tp.call.name = kstrdup(event, GFP_KERNEL);
 231         if (!tk->tp.call.name)
 232                 goto error;
 233
 234         tk->tp.class.system = kstrdup(group, GFP_KERNEL);
 235         if (!tk->tp.class.system)
 236                 goto error;
 237
 238         dyn_event_init(&tk->devent, &trace_kprobe_ops);
 239         INIT_LIST_HEAD(&tk->tp.files);
 240         return tk;
 241 error:
 242         kfree(tk->tp.call.name);
 243         kfree(tk->symbol);
 244         free_percpu(tk->nhit);
 245         kfree(tk);
 246         return ERR_PTR(ret);
 247 }
 248
 249 static void free_trace_kprobe(struct trace_kprobe *tk)
 250 {
 251         int i;
 252
 253         if (!tk)
 254                 return;
 255
 256         for (i = 0; i < tk->tp.nr_args; i++)
 257                 traceprobe_free_probe_arg(&tk->tp.args[i]);
 258
 259         kfree(tk->tp.call.class->system);
 260         kfree(tk->tp.call.name);
 261         kfree(tk->symbol);
 262         free_percpu(tk->nhit);
 263         kfree(tk);
 264 }
 265
 266 static struct trace_kprobe *find_trace_kprobe(const char *event,
 267                                               const char *group)
 268 {
 269         struct dyn_event *pos;
 270         struct trace_kprobe *tk;
 271
 272         for_each_trace_kprobe(tk, pos)
 273                 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
 274                     strcmp(tk->tp.call.class->system, group) == 0)
 275                         return tk;
 276         return NULL;
 277 }
 278
 279 static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
 280 {
 281         int ret = 0;
 282
 283         if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
 284                 if (trace_kprobe_is_return(tk))
 285                         ret = enable_kretprobe(&tk->rp);
 286                 else
 287                         ret = enable_kprobe(&tk->rp.kp);
 288         }
 289
 290         return ret;
 291 }
 292
 293 /*
 294  * Enable trace_probe
 295  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
 296  */
 297 static int
 298 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 299 {
 300         struct event_file_link *link;
 301         int ret = 0;
 302
 303         if (file) {
 304                 link = kmalloc(sizeof(*link), GFP_KERNEL);
 305                 if (!link) {
 306                         ret = -ENOMEM;
 307                         goto out;
 308                 }
 309
 310                 link->file = file;
 311                 list_add_tail_rcu(&link->list, &tk->tp.files);
 312
 313                 tk->tp.flags |= TP_FLAG_TRACE;
 314                 ret = __enable_trace_kprobe(tk);
 315                 if (ret) {
 316                         list_del_rcu(&link->list);
 317                         kfree(link);
 318                         tk->tp.flags &= ~TP_FLAG_TRACE;
 319                 }
 320
 321         } else {
 322                 tk->tp.flags |= TP_FLAG_PROFILE;
 323                 ret = __enable_trace_kprobe(tk);
 324                 if (ret)
 325                         tk->tp.flags &= ~TP_FLAG_PROFILE;
 326         }
 327  out:
 328         return ret;
 329 }
 330
 331 /*
 332  * Disable trace_probe
 333  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
 334  */
 335 static int
 336 disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 337 {
 338         struct event_file_link *link = NULL;
 339         int wait = 0;
 340         int ret = 0;
 341
 342         if (file) {
 343                 link = find_event_file_link(&tk->tp, file);
 344                 if (!link) {
 345                         ret = -EINVAL;
 346                         goto out;
 347                 }
 348
 349                 list_del_rcu(&link->list);
 350                 wait = 1;
 351                 if (!list_empty(&tk->tp.files))
 352                         goto out;
 353
 354                 tk->tp.flags &= ~TP_FLAG_TRACE;
 355         } else
 356                 tk->tp.flags &= ~TP_FLAG_PROFILE;
 357
 358         if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
 359                 if (trace_kprobe_is_return(tk))
 360                         disable_kretprobe(&tk->rp);
 361                 else
 362                         disable_kprobe(&tk->rp.kp);
 363                 wait = 1;
 364         }
 365
 366         /*
 367          * if tk is not added to any list, it must be a local trace_kprobe
 368          * created with perf_event_open. We don't need to wait for these
 369          * trace_kprobes
 370          */
 371         if (list_empty(&tk->devent.list))
 372                 wait = 0;
 373  out:
 374         if (wait) {
 375                 /*
 376                  * Synchronize with kprobe_trace_func/kretprobe_trace_func
 377                  * to ensure disabled (all running handlers are finished).
 378                  * This is not only for kfree(), but also the caller,
 379                  * trace_remove_event_call() supposes it for releasing
 380                  * event_call related objects, which will be accessed in
 381                  * the kprobe_trace_func/kretprobe_trace_func.
 382                  */
 383                 synchronize_rcu();
 384                 kfree(link);    /* Ignored if link == NULL */
 385         }
 386
 387         return ret;
 388 }
 389
 390 #if defined(CONFIG_KPROBES_ON_FTRACE) && \
 391         !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
 392 static bool within_notrace_func(struct trace_kprobe *tk)
 393 {
 394         unsigned long offset, size, addr;
 395
 396         addr = trace_kprobe_address(tk);
 397         if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
 398                 return false;
 399
 400         /* Get the entry address of the target function */
 401         addr -= offset;
 402
 403         /*
 404          * Since ftrace_location_range() does inclusive range check, we need
 405          * to subtract 1 byte from the end address.
 406          */
 407         return !ftrace_location_range(addr, addr + size - 1);
 408 }
 409 #else
 410 #define within_notrace_func(tk) (false)
 411 #endif
 412
 413 /* Internal register function - just handle k*probes and flags */
 414 static int __register_trace_kprobe(struct trace_kprobe *tk)
 415 {
 416         int i, ret;
 417
 418         if (trace_probe_is_registered(&tk->tp))
 419                 return -EINVAL;
 420
 421         if (within_notrace_func(tk)) {
 422                 pr_warn("Could not probe notrace function %s\n",
 423                         trace_kprobe_symbol(tk));
 424                 return -EINVAL;
 425         }
 426
 427         for (i = 0; i < tk->tp.nr_args; i++) {
 428                 ret = traceprobe_update_arg(&tk->tp.args[i]);
 429                 if (ret)
 430                         return ret;
 431         }
 432
 433         /* Set/clear disabled flag according to tp->flag */
 434         if (trace_probe_is_enabled(&tk->tp))
 435                 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
 436         else
 437                 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 438
 439         if (trace_kprobe_is_return(tk))
 440                 ret = register_kretprobe(&tk->rp);
 441         else
 442                 ret = register_kprobe(&tk->rp.kp);
 443
 444         if (ret == 0)
 445                 tk->tp.flags |= TP_FLAG_REGISTERED;
 446         return ret;
 447 }
 448
 449 /* Internal unregister function - just handle k*probes and flags */
 450 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 451 {
 452         if (trace_probe_is_registered(&tk->tp)) {
 453                 if (trace_kprobe_is_return(tk))
 454                         unregister_kretprobe(&tk->rp);
 455                 else
 456                         unregister_kprobe(&tk->rp.kp);
 457                 tk->tp.flags &= ~TP_FLAG_REGISTERED;
 458                 /* Cleanup kprobe for reuse */
 459                 if (tk->rp.kp.symbol_name)
 460                         tk->rp.kp.addr = NULL;
 461         }
 462 }
 463
 464 /* Unregister a trace_probe and probe_event */
 465 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 466 {
 467         /* Enabled event can not be unregistered */
 468         if (trace_probe_is_enabled(&tk->tp))
 469                 return -EBUSY;
 470
 471         /* Will fail if probe is being used by ftrace or perf */
 472         if (unregister_kprobe_event(tk))
 473                 return -EBUSY;
 474
 475         __unregister_trace_kprobe(tk);
 476         dyn_event_remove(&tk->devent);
 477
 478         return 0;
 479 }
 480
 481 /* Register a trace_probe and probe_event */
 482 static int register_trace_kprobe(struct trace_kprobe *tk)
 483 {
 484         struct trace_kprobe *old_tk;
 485         int ret;
 486
 487         mutex_lock(&event_mutex);
 488
 489         /* Delete old (same name) event if exist */
 490         old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
 491                         tk->tp.call.class->system);
 492         if (old_tk) {
 493                 ret = unregister_trace_kprobe(old_tk);
 494                 if (ret < 0)
 495                         goto end;
 496                 free_trace_kprobe(old_tk);
 497         }
 498
 499         /* Register new event */
 500         ret = register_kprobe_event(tk);
 501         if (ret) {
 502                 pr_warn("Failed to register probe event(%d)\n", ret);
 503                 goto end;
 504         }
 505
 506         /* Register k*probe */
 507         ret = __register_trace_kprobe(tk);
 508         if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
 509                 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 510                 ret = 0;
 511         }
 512
 513         if (ret < 0)
 514                 unregister_kprobe_event(tk);
 515         else
 516                 dyn_event_add(&tk->devent);
 517
 518 end:
 519         mutex_unlock(&event_mutex);
 520         return ret;
 521 }
 522
 523 /* Module notifier call back, checking event on the module */
 524 static int trace_kprobe_module_callback(struct notifier_block *nb,
 525                                        unsigned long val, void *data)
 526 {
 527         struct module *mod = data;
 528         struct dyn_event *pos;
 529         struct trace_kprobe *tk;
 530         int ret;
 531
 532         if (val != MODULE_STATE_COMING)
 533                 return NOTIFY_DONE;
 534
 535         /* Update probes on coming module */
 536         mutex_lock(&event_mutex);
 537         for_each_trace_kprobe(tk, pos) {
 538                 if (trace_kprobe_within_module(tk, mod)) {
 539                         /* Don't need to check busy - this should have gone. */
 540                         __unregister_trace_kprobe(tk);
 541                         ret = __register_trace_kprobe(tk);
 542                         if (ret)
 543                                 pr_warn("Failed to re-register probe %s on %s: %d\n",
 544                                         trace_event_name(&tk->tp.call),
 545                                         mod->name, ret);
 546                 }
 547         }
 548         mutex_unlock(&event_mutex);
 549
 550         return NOTIFY_DONE;
 551 }
 552
 553 static struct notifier_block trace_kprobe_module_nb = {
 554         .notifier_call = trace_kprobe_module_callback,
 555         .priority = 1   /* Invoked after kprobe module callback */
 556 };
 557
 558 /* Convert certain expected symbols into '_' when generating event names */
 559 static inline void sanitize_event_name(char *name)
 560 {
 561         while (*name++ != '\0')
 562                 if (*name == ':' || *name == '.')
 563                         *name = '_';
 564 }
 565
 566 static int trace_kprobe_create(int argc, const char *argv[])
 567 {
 568         /*
 569          * Argument syntax:
 570          *  - Add kprobe:
 571          *      p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 572          *  - Add kretprobe:
 573          *      r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
 574          * Fetch args:
 575          *  $retval     : fetch return value
 576          *  $stack      : fetch stack address
 577          *  $stackN     : fetch Nth of stack (N:0-)
 578          *  $comm       : fetch current task comm
 579          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 580          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 581          *  %REG        : fetch register REG
 582          * Dereferencing memory fetch:
 583          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 584          * Alias name of args:
 585          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 586          * Type of args:
 587          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 588          */
 589         struct trace_kprobe *tk = NULL;
 590         int i, len, ret = 0;
 591         bool is_return = false;
 592         char *symbol = NULL, *tmp = NULL;
 593         const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
 594         int maxactive = 0;
 595         long offset = 0;
 596         void *addr = NULL;
 597         char buf[MAX_EVENT_NAME_LEN];
 598         unsigned int flags = TPARG_FL_KERNEL;
 599
 600         switch (argv[0][0]) {
 601         case 'r':
 602                 is_return = true;
 603                 flags |= TPARG_FL_RETURN;
 604                 break;
 605         case 'p':
 606                 break;
 607         default:
 608                 return -ECANCELED;
 609         }
 610         if (argc < 2)
 611                 return -ECANCELED;
 612
 613         trace_probe_log_init("trace_kprobe", argc, argv);
 614
 615         event = strchr(&argv[0][1], ':');
 616         if (event)
 617                 event++;
 618
 619         if (isdigit(argv[0][1])) {
 620                 if (!is_return) {
 621                         trace_probe_log_err(1, MAXACT_NO_KPROBE);
 622                         goto parse_error;
 623                 }
 624                 if (event)
 625                         len = event - &argv[0][1] - 1;
 626                 else
 627                         len = strlen(&argv[0][1]);
 628                 if (len > MAX_EVENT_NAME_LEN - 1) {
 629                         trace_probe_log_err(1, BAD_MAXACT);
 630                         goto parse_error;
 631                 }
 632                 memcpy(buf, &argv[0][1], len);
 633                 buf[len] = '\0';
 634                 ret = kstrtouint(buf, 0, &maxactive);
 635                 if (ret || !maxactive) {
 636                         trace_probe_log_err(1, BAD_MAXACT);
 637                         goto parse_error;
 638                 }
 639                 /* kretprobes instances are iterated over via a list. The
 640                  * maximum should stay reasonable.
 641                  */
 642                 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
 643                         trace_probe_log_err(1, MAXACT_TOO_BIG);
 644                         goto parse_error;
 645                 }
 646         }
 647
 648         /* try to parse an address. if that fails, try to read the
 649          * input as a symbol. */
 650         if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
 651                 trace_probe_log_set_index(1);
 652                 /* Check whether uprobe event specified */
 653                 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
 654                         ret = -ECANCELED;
 655                         goto error;
 656                 }
 657                 /* a symbol specified */
 658                 symbol = kstrdup(argv[1], GFP_KERNEL);
 659                 if (!symbol)
 660                         return -ENOMEM;
 661                 /* TODO: support .init module functions */
 662                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 663                 if (ret || offset < 0 || offset > UINT_MAX) {
 664                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 665                         goto parse_error;
 666                 }
 667                 if (kprobe_on_func_entry(NULL, symbol, offset))
 668                         flags |= TPARG_FL_FENTRY;
 669                 if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {
 670                         trace_probe_log_err(0, BAD_RETPROBE);
 671                         goto parse_error;
 672                 }
 673         }
 674
 675         trace_probe_log_set_index(0);
 676         if (event) {
 677                 ret = traceprobe_parse_event_name(&event, &group, buf,
 678                                                   event - argv[0]);
 679                 if (ret)
 680                         goto parse_error;
 681         } else {
 682                 /* Make a new event name */
 683                 if (symbol)
 684                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 685                                  is_return ? 'r' : 'p', symbol, offset);
 686                 else
 687                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 688                                  is_return ? 'r' : 'p', addr);
 689                 sanitize_event_name(buf);
 690                 event = buf;
 691         }
 692
 693         /* setup a probe */
 694         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
 695                                argc - 2, is_return);
 696         if (IS_ERR(tk)) {
 697                 ret = PTR_ERR(tk);
 698                 /* This must return -ENOMEM, else there is a bug */
 699                 WARN_ON_ONCE(ret != -ENOMEM);
 700                 goto out;       /* We know tk is not allocated */
 701         }
 702         argc -= 2; argv += 2;
 703
 704         /* parse arguments */
 705         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 706                 tmp = kstrdup(argv[i], GFP_KERNEL);
 707                 if (!tmp) {
 708                         ret = -ENOMEM;
 709                         goto error;
 710                 }
 711
 712                 trace_probe_log_set_index(i + 2);
 713                 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
 714                 kfree(tmp);
 715                 if (ret)
 716                         goto error;     /* This can be -ENOMEM */
 717         }
 718
 719         ret = register_trace_kprobe(tk);
 720         if (ret) {
 721                 trace_probe_log_set_index(1);
 722                 if (ret == -EILSEQ)
 723                         trace_probe_log_err(0, BAD_INSN_BNDRY);
 724                 else if (ret == -ENOENT)
 725                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 726                 else if (ret != -ENOMEM)
 727                         trace_probe_log_err(0, FAIL_REG_PROBE);
 728                 goto error;
 729         }
 730
 731 out:
 732         trace_probe_log_clear();
 733         kfree(symbol);
 734         return ret;
 735
 736 parse_error:
 737         ret = -EINVAL;
 738 error:
 739         free_trace_kprobe(tk);
 740         goto out;
 741 }
 742
 743 static int create_or_delete_trace_kprobe(int argc, char **argv)
 744 {
 745         int ret;
 746
 747         if (argv[0][0] == '-')
 748                 return dyn_event_release(argc, argv, &trace_kprobe_ops);
 749
 750         ret = trace_kprobe_create(argc, (const char **)argv);
 751         return ret == -ECANCELED ? -EINVAL : ret;
 752 }
 753
 754 static int trace_kprobe_release(struct dyn_event *ev)
 755 {
 756         struct trace_kprobe *tk = to_trace_kprobe(ev);
 757         int ret = unregister_trace_kprobe(tk);
 758
 759         if (!ret)
 760                 free_trace_kprobe(tk);
 761         return ret;
 762 }
 763
 764 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
 765 {
 766         struct trace_kprobe *tk = to_trace_kprobe(ev);
 767         int i;
 768
 769         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
 770         seq_printf(m, ":%s/%s", tk->tp.call.class->system,
 771                         trace_event_name(&tk->tp.call));
 772
 773         if (!tk->symbol)
 774                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
 775         else if (tk->rp.kp.offset)
 776                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
 777                            tk->rp.kp.offset);
 778         else
 779                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
 780
 781         for (i = 0; i < tk->tp.nr_args; i++)
 782                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
 783         seq_putc(m, '\n');
 784
 785         return 0;
 786 }
 787
 788 static int probes_seq_show(struct seq_file *m, void *v)
 789 {
 790         struct dyn_event *ev = v;
 791
 792         if (!is_trace_kprobe(ev))
 793                 return 0;
 794
 795         return trace_kprobe_show(m, ev);
 796 }
 797
 798 static const struct seq_operations probes_seq_op = {
 799         .start  = dyn_event_seq_start,
 800         .next   = dyn_event_seq_next,
 801         .stop   = dyn_event_seq_stop,
 802         .show   = probes_seq_show
 803 };
 804
 805 static int probes_open(struct inode *inode, struct file *file)
 806 {
 807         int ret;
 808
 809         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 810                 ret = dyn_events_release_all(&trace_kprobe_ops);
 811                 if (ret < 0)
 812                         return ret;
 813         }
 814
 815         return seq_open(file, &probes_seq_op);
 816 }
 817
 818 static ssize_t probes_write(struct file *file, const char __user *buffer,
 819                             size_t count, loff_t *ppos)
 820 {
 821         return trace_parse_run_command(file, buffer, count, ppos,
 822                                        create_or_delete_trace_kprobe);
 823 }
 824
 825 static const struct file_operations kprobe_events_ops = {
 826         .owner          = THIS_MODULE,
 827         .open           = probes_open,
 828         .read           = seq_read,
 829         .llseek         = seq_lseek,
 830         .release        = seq_release,
 831         .write          = probes_write,
 832 };
 833
 834 /* Probes profiling interfaces */
 835 static int probes_profile_seq_show(struct seq_file *m, void *v)
 836 {
 837         struct dyn_event *ev = v;
 838         struct trace_kprobe *tk;
 839
 840         if (!is_trace_kprobe(ev))
 841                 return 0;
 842
 843         tk = to_trace_kprobe(ev);
 844         seq_printf(m, "  %-44s %15lu %15lu\n",
 845                    trace_event_name(&tk->tp.call),
 846                    trace_kprobe_nhit(tk),
 847                    tk->rp.kp.nmissed);
 848
 849         return 0;
 850 }
 851
 852 static const struct seq_operations profile_seq_op = {
 853         .start  = dyn_event_seq_start,
 854         .next   = dyn_event_seq_next,
 855         .stop   = dyn_event_seq_stop,
 856         .show   = probes_profile_seq_show
 857 };
 858
 859 static int profile_open(struct inode *inode, struct file *file)
 860 {
 861         return seq_open(file, &profile_seq_op);
 862 }
 863
 864 static const struct file_operations kprobe_profile_ops = {
 865         .owner          = THIS_MODULE,
 866         .open           = profile_open,
 867         .read           = seq_read,
 868         .llseek         = seq_lseek,
 869         .release        = seq_release,
 870 };
 871
 872 /* Kprobe specific fetch functions */
 873
 874 /* Return the length of string -- including null terminal byte */
 875 static nokprobe_inline int
 876 fetch_store_strlen(unsigned long addr)
 877 {
 878         int ret, len = 0;
 879         u8 c;
 880
 881         do {
 882                 ret = probe_kernel_read(&c, (u8 *)addr + len, 1);
 883                 len++;
 884         } while (c && ret == 0 && len < MAX_STRING_SIZE);
 885
 886         return (ret < 0) ? ret : len;
 887 }
 888
 889 /*
 890  * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
 891  * length and relative data location.
 892  */
 893 static nokprobe_inline int
 894 fetch_store_string(unsigned long addr, void *dest, void *base)
 895 {
 896         int maxlen = get_loc_len(*(u32 *)dest);
 897         u8 *dst = get_loc_data(dest, base);
 898         long ret;
 899
 900         if (unlikely(!maxlen))
 901                 return -ENOMEM;
 902         /*
 903          * Try to get string again, since the string can be changed while
 904          * probing.
 905          */
 906         ret = strncpy_from_unsafe(dst, (void *)addr, maxlen);
 907
 908         if (ret >= 0)
 909                 *(u32 *)dest = make_data_loc(ret, (void *)dst - base);
 910         return ret;
 911 }
 912
 913 static nokprobe_inline int
 914 probe_mem_read(void *dest, void *src, size_t size)
 915 {
 916         return probe_kernel_read(dest, src, size);
 917 }
 918
 919 /* Note that we don't verify it, since the code does not come from user space */
 920 static int
 921 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
 922                    void *base)
 923 {
 924         unsigned long val;
 925
 926 retry:
 927         /* 1st stage: get value from context */
 928         switch (code->op) {
 929         case FETCH_OP_REG:
 930                 val = regs_get_register(regs, code->param);
 931                 break;
 932         case FETCH_OP_STACK:
 933                 val = regs_get_kernel_stack_nth(regs, code->param);
 934                 break;
 935         case FETCH_OP_STACKP:
 936                 val = kernel_stack_pointer(regs);
 937                 break;
 938         case FETCH_OP_RETVAL:
 939                 val = regs_return_value(regs);
 940                 break;
 941         case FETCH_OP_IMM:
 942                 val = code->immediate;
 943                 break;
 944         case FETCH_OP_COMM:
 945                 val = (unsigned long)current->comm;
 946                 break;
 947 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
 948         case FETCH_OP_ARG:
 949                 val = regs_get_kernel_argument(regs, code->param);
 950                 break;
 951 #endif
 952         case FETCH_NOP_SYMBOL:  /* Ignore a place holder */
 953                 code++;
 954                 goto retry;
 955         default:
 956                 return -EILSEQ;
 957         }
 958         code++;
 959
 960         return process_fetch_insn_bottom(code, val, dest, base);
 961 }
 962 NOKPROBE_SYMBOL(process_fetch_insn)
 963
 964 /* Kprobe handler */
 965 static nokprobe_inline void
 966 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
 967                     struct trace_event_file *trace_file)
 968 {
 969         struct kprobe_trace_entry_head *entry;
 970         struct ring_buffer_event *event;
 971         struct ring_buffer *buffer;
 972         int size, dsize, pc;
 973         unsigned long irq_flags;
 974         struct trace_event_call *call = &tk->tp.call;
 975
 976         WARN_ON(call != trace_file->event_call);
 977
 978         if (trace_trigger_soft_disabled(trace_file))
 979                 return;
 980
 981         local_save_flags(irq_flags);
 982         pc = preempt_count();
 983
 984         dsize = __get_data_size(&tk->tp, regs);
 985         size = sizeof(*entry) + tk->tp.size + dsize;
 986
 987         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
 988                                                 call->event.type,
 989                                                 size, irq_flags, pc);
 990         if (!event)
 991                 return;
 992
 993         entry = ring_buffer_event_data(event);
 994         entry->ip = (unsigned long)tk->rp.kp.addr;
 995         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
 996
 997         event_trigger_unlock_commit_regs(trace_file, buffer, event,
 998                                          entry, irq_flags, pc, regs);
 999 }
1000
1001 static void
1002 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1003 {
1004         struct event_file_link *link;
1005
1006         list_for_each_entry_rcu(link, &tk->tp.files, list)
1007                 __kprobe_trace_func(tk, regs, link->file);
1008 }
1009 NOKPROBE_SYMBOL(kprobe_trace_func);
1010
1011 /* Kretprobe handler */
1012 static nokprobe_inline void
1013 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1014                        struct pt_regs *regs,
1015                        struct trace_event_file *trace_file)
1016 {
1017         struct kretprobe_trace_entry_head *entry;
1018         struct ring_buffer_event *event;
1019         struct ring_buffer *buffer;
1020         int size, pc, dsize;
1021         unsigned long irq_flags;
1022         struct trace_event_call *call = &tk->tp.call;
1023
1024         WARN_ON(call != trace_file->event_call);
1025
1026         if (trace_trigger_soft_disabled(trace_file))
1027                 return;
1028
1029         local_save_flags(irq_flags);
1030         pc = preempt_count();
1031
1032         dsize = __get_data_size(&tk->tp, regs);
1033         size = sizeof(*entry) + tk->tp.size + dsize;
1034
1035         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1036                                                 call->event.type,
1037                                                 size, irq_flags, pc);
1038         if (!event)
1039                 return;
1040
1041         entry = ring_buffer_event_data(event);
1042         entry->func = (unsigned long)tk->rp.kp.addr;
1043         entry->ret_ip = (unsigned long)ri->ret_addr;
1044         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1045
1046         event_trigger_unlock_commit_regs(trace_file, buffer, event,
1047                                          entry, irq_flags, pc, regs);
1048 }
1049
1050 static void
1051 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1052                      struct pt_regs *regs)
1053 {
1054         struct event_file_link *link;
1055
1056         list_for_each_entry_rcu(link, &tk->tp.files, list)
1057                 __kretprobe_trace_func(tk, ri, regs, link->file);
1058 }
1059 NOKPROBE_SYMBOL(kretprobe_trace_func);
1060
1061 /* Event entry printers */
1062 static enum print_line_t
1063 print_kprobe_event(struct trace_iterator *iter, int flags,
1064                    struct trace_event *event)
1065 {
1066         struct kprobe_trace_entry_head *field;
1067         struct trace_seq *s = &iter->seq;
1068         struct trace_probe *tp;
1069
1070         field = (struct kprobe_trace_entry_head *)iter->ent;
1071         tp = container_of(event, struct trace_probe, call.event);
1072
1073         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1074
1075         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1076                 goto out;
1077
1078         trace_seq_putc(s, ')');
1079
1080         if (print_probe_args(s, tp->args, tp->nr_args,
1081                              (u8 *)&field[1], field) < 0)
1082                 goto out;
1083
1084         trace_seq_putc(s, '\n');
1085  out:
1086         return trace_handle_return(s);
1087 }
1088
1089 static enum print_line_t
1090 print_kretprobe_event(struct trace_iterator *iter, int flags,
1091                       struct trace_event *event)
1092 {
1093         struct kretprobe_trace_entry_head *field;
1094         struct trace_seq *s = &iter->seq;
1095         struct trace_probe *tp;
1096
1097         field = (struct kretprobe_trace_entry_head *)iter->ent;
1098         tp = container_of(event, struct trace_probe, call.event);
1099
1100         trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1101
1102         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1103                 goto out;
1104
1105         trace_seq_puts(s, " <- ");
1106
1107         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1108                 goto out;
1109
1110         trace_seq_putc(s, ')');
1111
1112         if (print_probe_args(s, tp->args, tp->nr_args,
1113                              (u8 *)&field[1], field) < 0)
1114                 goto out;
1115
1116         trace_seq_putc(s, '\n');
1117
1118  out:
1119         return trace_handle_return(s);
1120 }
1121
1122
1123 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1124 {
1125         int ret;
1126         struct kprobe_trace_entry_head field;
1127         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1128
1129         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1130
1131         return traceprobe_define_arg_fields(event_call, sizeof(field), &tk->tp);
1132 }
1133
1134 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1135 {
1136         int ret;
1137         struct kretprobe_trace_entry_head field;
1138         struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1139
1140         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1141         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1142
1143         return traceprobe_define_arg_fields(event_call, sizeof(field), &tk->tp);
1144 }
1145
1146 #ifdef CONFIG_PERF_EVENTS
1147
1148 /* Kprobe profile handler */
1149 static int
1150 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1151 {
1152         struct trace_event_call *call = &tk->tp.call;
1153         struct kprobe_trace_entry_head *entry;
1154         struct hlist_head *head;
1155         int size, __size, dsize;
1156         int rctx;
1157
1158         if (bpf_prog_array_valid(call)) {
1159                 unsigned long orig_ip = instruction_pointer(regs);
1160                 int ret;
1161
1162                 ret = trace_call_bpf(call, regs);
1163
1164                 /*
1165                  * We need to check and see if we modified the pc of the
1166                  * pt_regs, and if so return 1 so that we don't do the
1167                  * single stepping.
1168                  */
1169                 if (orig_ip != instruction_pointer(regs))
1170                         return 1;
1171                 if (!ret)
1172                         return 0;
1173         }
1174
1175         head = this_cpu_ptr(call->perf_events);
1176         if (hlist_empty(head))
1177                 return 0;
1178
1179         dsize = __get_data_size(&tk->tp, regs);
1180         __size = sizeof(*entry) + tk->tp.size + dsize;
1181         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1182         size -= sizeof(u32);
1183
1184         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1185         if (!entry)
1186                 return 0;
1187
1188         entry->ip = (unsigned long)tk->rp.kp.addr;
1189         memset(&entry[1], 0, dsize);
1190         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1191         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1192                               head, NULL);
1193         return 0;
1194 }
1195 NOKPROBE_SYMBOL(kprobe_perf_func);
1196
1197 /* Kretprobe profile handler */
1198 static void
1199 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1200                     struct pt_regs *regs)
1201 {
1202         struct trace_event_call *call = &tk->tp.call;
1203         struct kretprobe_trace_entry_head *entry;
1204         struct hlist_head *head;
1205         int size, __size, dsize;
1206         int rctx;
1207
1208         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1209                 return;
1210
1211         head = this_cpu_ptr(call->perf_events);
1212         if (hlist_empty(head))
1213                 return;
1214
1215         dsize = __get_data_size(&tk->tp, regs);
1216         __size = sizeof(*entry) + tk->tp.size + dsize;
1217         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1218         size -= sizeof(u32);
1219
1220         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1221         if (!entry)
1222                 return;
1223
1224         entry->func = (unsigned long)tk->rp.kp.addr;
1225         entry->ret_ip = (unsigned long)ri->ret_addr;
1226         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1227         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1228                               head, NULL);
1229 }
1230 NOKPROBE_SYMBOL(kretprobe_perf_func);
1231
1232 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1233                         const char **symbol, u64 *probe_offset,
1234                         u64 *probe_addr, bool perf_type_tracepoint)
1235 {
1236         const char *pevent = trace_event_name(event->tp_event);
1237         const char *group = event->tp_event->class->system;
1238         struct trace_kprobe *tk;
1239
1240         if (perf_type_tracepoint)
1241                 tk = find_trace_kprobe(pevent, group);
1242         else
1243                 tk = event->tp_event->data;
1244         if (!tk)
1245                 return -EINVAL;
1246
1247         *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1248                                               : BPF_FD_TYPE_KPROBE;
1249         if (tk->symbol) {
1250                 *symbol = tk->symbol;
1251                 *probe_offset = tk->rp.kp.offset;
1252                 *probe_addr = 0;
1253         } else {
1254                 *symbol = NULL;
1255                 *probe_offset = 0;
1256                 *probe_addr = (unsigned long)tk->rp.kp.addr;
1257         }
1258         return 0;
1259 }
1260 #endif  /* CONFIG_PERF_EVENTS */
1261
1262 /*
1263  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1264  *
1265  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1266  * lockless, but we can't race with this __init function.
1267  */
1268 static int kprobe_register(struct trace_event_call *event,
1269                            enum trace_reg type, void *data)
1270 {
1271         struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1272         struct trace_event_file *file = data;
1273
1274         switch (type) {
1275         case TRACE_REG_REGISTER:
1276                 return enable_trace_kprobe(tk, file);
1277         case TRACE_REG_UNREGISTER:
1278                 return disable_trace_kprobe(tk, file);
1279
1280 #ifdef CONFIG_PERF_EVENTS
1281         case TRACE_REG_PERF_REGISTER:
1282                 return enable_trace_kprobe(tk, NULL);
1283         case TRACE_REG_PERF_UNREGISTER:
1284                 return disable_trace_kprobe(tk, NULL);
1285         case TRACE_REG_PERF_OPEN:
1286         case TRACE_REG_PERF_CLOSE:
1287         case TRACE_REG_PERF_ADD:
1288         case TRACE_REG_PERF_DEL:
1289                 return 0;
1290 #endif
1291         }
1292         return 0;
1293 }
1294
1295 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1296 {
1297         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1298         int ret = 0;
1299
1300         raw_cpu_inc(*tk->nhit);
1301
1302         if (tk->tp.flags & TP_FLAG_TRACE)
1303                 kprobe_trace_func(tk, regs);
1304 #ifdef CONFIG_PERF_EVENTS
1305         if (tk->tp.flags & TP_FLAG_PROFILE)
1306                 ret = kprobe_perf_func(tk, regs);
1307 #endif
1308         return ret;
1309 }
1310 NOKPROBE_SYMBOL(kprobe_dispatcher);
1311
1312 static int
1313 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1314 {
1315         struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1316
1317         raw_cpu_inc(*tk->nhit);
1318
1319         if (tk->tp.flags & TP_FLAG_TRACE)
1320                 kretprobe_trace_func(tk, ri, regs);
1321 #ifdef CONFIG_PERF_EVENTS
1322         if (tk->tp.flags & TP_FLAG_PROFILE)
1323                 kretprobe_perf_func(tk, ri, regs);
1324 #endif
1325         return 0;       /* We don't tweek kernel, so just return 0 */
1326 }
1327 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1328
1329 static struct trace_event_functions kretprobe_funcs = {
1330         .trace          = print_kretprobe_event
1331 };
1332
1333 static struct trace_event_functions kprobe_funcs = {
1334         .trace          = print_kprobe_event
1335 };
1336
1337 static inline void init_trace_event_call(struct trace_kprobe *tk,
1338                                          struct trace_event_call *call)
1339 {
1340         INIT_LIST_HEAD(&call->class->fields);
1341         if (trace_kprobe_is_return(tk)) {
1342                 call->event.funcs = &kretprobe_funcs;
1343                 call->class->define_fields = kretprobe_event_define_fields;
1344         } else {
1345                 call->event.funcs = &kprobe_funcs;
1346                 call->class->define_fields = kprobe_event_define_fields;
1347         }
1348
1349         call->flags = TRACE_EVENT_FL_KPROBE;
1350         call->class->reg = kprobe_register;
1351         call->data = tk;
1352 }
1353
1354 static int register_kprobe_event(struct trace_kprobe *tk)
1355 {
1356         struct trace_event_call *call = &tk->tp.call;
1357         int ret = 0;
1358
1359         init_trace_event_call(tk, call);
1360
1361         if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1362                 return -ENOMEM;
1363         ret = register_trace_event(&call->event);
1364         if (!ret) {
1365                 kfree(call->print_fmt);
1366                 return -ENODEV;
1367         }
1368         ret = trace_add_event_call(call);
1369         if (ret) {
1370                 pr_info("Failed to register kprobe event: %s\n",
1371                         trace_event_name(call));
1372                 kfree(call->print_fmt);
1373                 unregister_trace_event(&call->event);
1374         }
1375         return ret;
1376 }
1377
1378 static int unregister_kprobe_event(struct trace_kprobe *tk)
1379 {
1380         int ret;
1381
1382         /* tp->event is unregistered in trace_remove_event_call() */
1383         ret = trace_remove_event_call(&tk->tp.call);
1384         if (!ret)
1385                 kfree(tk->tp.call.print_fmt);
1386         return ret;
1387 }
1388
1389 #ifdef CONFIG_PERF_EVENTS
1390 /* create a trace_kprobe, but don't add it to global lists */
1391 struct trace_event_call *
1392 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1393                           bool is_return)
1394 {
1395         struct trace_kprobe *tk;
1396         int ret;
1397         char *event;
1398
1399         /*
1400          * local trace_kprobes are not added to dyn_event, so they are never
1401          * searched in find_trace_kprobe(). Therefore, there is no concern of
1402          * duplicated name here.
1403          */
1404         event = func ? func : "DUMMY_EVENT";
1405
1406         tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1407                                 offs, 0 /* maxactive */, 0 /* nargs */,
1408                                 is_return);
1409
1410         if (IS_ERR(tk)) {
1411                 pr_info("Failed to allocate trace_probe.(%d)\n",
1412                         (int)PTR_ERR(tk));
1413                 return ERR_CAST(tk);
1414         }
1415
1416         init_trace_event_call(tk, &tk->tp.call);
1417
1418         if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1419                 ret = -ENOMEM;
1420                 goto error;
1421         }
1422
1423         ret = __register_trace_kprobe(tk);
1424         if (ret < 0) {
1425                 kfree(tk->tp.call.print_fmt);
1426                 goto error;
1427         }
1428
1429         return &tk->tp.call;
1430 error:
1431         free_trace_kprobe(tk);
1432         return ERR_PTR(ret);
1433 }
1434
1435 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1436 {
1437         struct trace_kprobe *tk;
1438
1439         tk = container_of(event_call, struct trace_kprobe, tp.call);
1440
1441         if (trace_probe_is_enabled(&tk->tp)) {
1442                 WARN_ON(1);
1443                 return;
1444         }
1445
1446         __unregister_trace_kprobe(tk);
1447
1448         kfree(tk->tp.call.print_fmt);
1449         free_trace_kprobe(tk);
1450 }
1451 #endif /* CONFIG_PERF_EVENTS */
1452
1453 /* Make a tracefs interface for controlling probe points */
1454 static __init int init_kprobe_trace(void)
1455 {
1456         struct dentry *d_tracer;
1457         struct dentry *entry;
1458         int ret;
1459
1460         ret = dyn_event_register(&trace_kprobe_ops);
1461         if (ret)
1462                 return ret;
1463
1464         if (register_module_notifier(&trace_kprobe_module_nb))
1465                 return -EINVAL;
1466
1467         d_tracer = tracing_init_dentry();
1468         if (IS_ERR(d_tracer))
1469                 return 0;
1470
1471         entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1472                                     NULL, &kprobe_events_ops);
1473
1474         /* Event list interface */
1475         if (!entry)
1476                 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1477
1478         /* Profile interface */
1479         entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1480                                     NULL, &kprobe_profile_ops);
1481
1482         if (!entry)
1483                 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1484         return 0;
1485 }
1486 fs_initcall(init_kprobe_trace);
1487
1488
1489 #ifdef CONFIG_FTRACE_STARTUP_TEST
1490 static __init struct trace_event_file *
1491 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1492 {
1493         struct trace_event_file *file;
1494
1495         list_for_each_entry(file, &tr->events, list)
1496                 if (file->event_call == &tk->tp.call)
1497                         return file;
1498
1499         return NULL;
1500 }
1501
1502 /*
1503  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1504  * stage, we can do this lockless.
1505  */
1506 static __init int kprobe_trace_self_tests_init(void)
1507 {
1508         int ret, warn = 0;
1509         int (*target)(int, int, int, int, int, int);
1510         struct trace_kprobe *tk;
1511         struct trace_event_file *file;
1512
1513         if (tracing_is_disabled())
1514                 return -ENODEV;
1515
1516         target = kprobe_trace_selftest_target;
1517
1518         pr_info("Testing kprobe tracing: ");
1519
1520         ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)",
1521                                 create_or_delete_trace_kprobe);
1522         if (WARN_ON_ONCE(ret)) {
1523                 pr_warn("error on probing function entry.\n");
1524                 warn++;
1525         } else {
1526                 /* Enable trace point */
1527                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1528                 if (WARN_ON_ONCE(tk == NULL)) {
1529                         pr_warn("error on getting new probe.\n");
1530                         warn++;
1531                 } else {
1532                         file = find_trace_probe_file(tk, top_trace_array());
1533                         if (WARN_ON_ONCE(file == NULL)) {
1534                                 pr_warn("error on getting probe file.\n");
1535                                 warn++;
1536                         } else
1537                                 enable_trace_kprobe(tk, file);
1538                 }
1539         }
1540
1541         ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval",
1542                                 create_or_delete_trace_kprobe);
1543         if (WARN_ON_ONCE(ret)) {
1544                 pr_warn("error on probing function return.\n");
1545                 warn++;
1546         } else {
1547                 /* Enable trace point */
1548                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1549                 if (WARN_ON_ONCE(tk == NULL)) {
1550                         pr_warn("error on getting 2nd new probe.\n");
1551                         warn++;
1552                 } else {
1553                         file = find_trace_probe_file(tk, top_trace_array());
1554                         if (WARN_ON_ONCE(file == NULL)) {
1555                                 pr_warn("error on getting probe file.\n");
1556                                 warn++;
1557                         } else
1558                                 enable_trace_kprobe(tk, file);
1559                 }
1560         }
1561
1562         if (warn)
1563                 goto end;
1564
1565         ret = target(1, 2, 3, 4, 5, 6);
1566
1567         /*
1568          * Not expecting an error here, the check is only to prevent the
1569          * optimizer from removing the call to target() as otherwise there
1570          * are no side-effects and the call is never performed.
1571          */
1572         if (ret != 21)
1573                 warn++;
1574
1575         /* Disable trace points before removing it */
1576         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1577         if (WARN_ON_ONCE(tk == NULL)) {
1578                 pr_warn("error on getting test probe.\n");
1579                 warn++;
1580         } else {
1581                 if (trace_kprobe_nhit(tk) != 1) {
1582                         pr_warn("incorrect number of testprobe hits\n");
1583                         warn++;
1584                 }
1585
1586                 file = find_trace_probe_file(tk, top_trace_array());
1587                 if (WARN_ON_ONCE(file == NULL)) {
1588                         pr_warn("error on getting probe file.\n");
1589                         warn++;
1590                 } else
1591                         disable_trace_kprobe(tk, file);
1592         }
1593
1594         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1595         if (WARN_ON_ONCE(tk == NULL)) {
1596                 pr_warn("error on getting 2nd test probe.\n");
1597                 warn++;
1598         } else {
1599                 if (trace_kprobe_nhit(tk) != 1) {
1600                         pr_warn("incorrect number of testprobe2 hits\n");
1601                         warn++;
1602                 }
1603
1604                 file = find_trace_probe_file(tk, top_trace_array());
1605                 if (WARN_ON_ONCE(file == NULL)) {
1606                         pr_warn("error on getting probe file.\n");
1607                         warn++;
1608                 } else
1609                         disable_trace_kprobe(tk, file);
1610         }
1611
1612         ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe);
1613         if (WARN_ON_ONCE(ret)) {
1614                 pr_warn("error on deleting a probe.\n");
1615                 warn++;
1616         }
1617
1618         ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe);
1619         if (WARN_ON_ONCE(ret)) {
1620                 pr_warn("error on deleting a probe.\n");
1621                 warn++;
1622         }
1623
1624 end:
1625         ret = dyn_events_release_all(&trace_kprobe_ops);
1626         if (WARN_ON_ONCE(ret)) {
1627                 pr_warn("error on cleaning up probes.\n");
1628                 warn++;
1629         }
1630         /*
1631          * Wait for the optimizer work to finish. Otherwise it might fiddle
1632          * with probes in already freed __init text.
1633          */
1634         wait_for_kprobe_optimizer();
1635         if (warn)
1636                 pr_cont("NG: Some tests are failed. Please check them.\n");
1637         else
1638                 pr_cont("OK\n");
1639         return 0;
1640 }
1641
1642 late_initcall(kprobe_trace_self_tests_init);
1643
1644 #endif