tools/perf/util/probe-finder.c

   1 /*
   2  * probe-finder.c : C expression to kprobe event converter
   3  *
   4  * Written by Masami Hiramatsu <[email protected]>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  *
  20  */
  21
  22 #include <sys/utsname.h>
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <fcntl.h>
  26 #include <errno.h>
  27 #include <stdio.h>
  28 #include <unistd.h>
  29 #include <getopt.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <stdarg.h>
  33 #include <ctype.h>
  34 #include <dwarf-regs.h>
  35
  36 #include "string.h"
  37 #include "event.h"
  38 #include "debug.h"
  39 #include "util.h"
  40 #include "probe-finder.h"
  41
  42 /* Kprobe tracer basic type is up to u64 */
  43 #define MAX_BASIC_TYPE_BITS     64
  44
  45 /*
  46  * Compare the tail of two strings.
  47  * Return 0 if whole of either string is same as another's tail part.
  48  */
  49 static int strtailcmp(const char *s1, const char *s2)
  50 {
  51         int i1 = strlen(s1);
  52         int i2 = strlen(s2);
  53         while (--i1 >= 0 && --i2 >= 0) {
  54                 if (s1[i1] != s2[i2])
  55                         return s1[i1] - s2[i2];
  56         }
  57         return 0;
  58 }
  59
  60 /* Line number list operations */
  61
  62 /* Add a line to line number list */
  63 static int line_list__add_line(struct list_head *head, int line)
  64 {
  65         struct line_node *ln;
  66         struct list_head *p;
  67
  68         /* Reverse search, because new line will be the last one */
  69         list_for_each_entry_reverse(ln, head, list) {
  70                 if (ln->line < line) {
  71                         p = &ln->list;
  72                         goto found;
  73                 } else if (ln->line == line)    /* Already exist */
  74                         return 1;
  75         }
  76         /* List is empty, or the smallest entry */
  77         p = head;
  78 found:
  79         pr_debug("line list: add a line %u\n", line);
  80         ln = zalloc(sizeof(struct line_node));
  81         if (ln == NULL)
  82                 return -ENOMEM;
  83         ln->line = line;
  84         INIT_LIST_HEAD(&ln->list);
  85         list_add(&ln->list, p);
  86         return 0;
  87 }
  88
  89 /* Check if the line in line number list */
  90 static int line_list__has_line(struct list_head *head, int line)
  91 {
  92         struct line_node *ln;
  93
  94         /* Reverse search, because new line will be the last one */
  95         list_for_each_entry(ln, head, list)
  96                 if (ln->line == line)
  97                         return 1;
  98
  99         return 0;
 100 }
 101
 102 /* Init line number list */
 103 static void line_list__init(struct list_head *head)
 104 {
 105         INIT_LIST_HEAD(head);
 106 }
 107
 108 /* Free line number list */
 109 static void line_list__free(struct list_head *head)
 110 {
 111         struct line_node *ln;
 112         while (!list_empty(head)) {
 113                 ln = list_first_entry(head, struct line_node, list);
 114                 list_del(&ln->list);
 115                 free(ln);
 116         }
 117 }
 118
 119 /* Dwarf wrappers */
 120
 121 /* Find the realpath of the target file. */
 122 static const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
 123 {
 124         Dwarf_Files *files;
 125         size_t nfiles, i;
 126         const char *src = NULL;
 127         int ret;
 128
 129         if (!fname)
 130                 return NULL;
 131
 132         ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
 133         if (ret != 0)
 134                 return NULL;
 135
 136         for (i = 0; i < nfiles; i++) {
 137                 src = dwarf_filesrc(files, i, NULL, NULL);
 138                 if (strtailcmp(src, fname) == 0)
 139                         break;
 140         }
 141         if (i == nfiles)
 142                 return NULL;
 143         return src;
 144 }
 145
 146 /* Compare diename and tname */
 147 static bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
 148 {
 149         const char *name;
 150         name = dwarf_diename(dw_die);
 151         return name ? strcmp(tname, name) : -1;
 152 }
 153
 154 /* Get type die, but skip qualifiers and typedef */
 155 static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
 156 {
 157         Dwarf_Attribute attr;
 158         int tag;
 159
 160         do {
 161                 if (dwarf_attr(vr_die, DW_AT_type, &attr) == NULL ||
 162                     dwarf_formref_die(&attr, die_mem) == NULL)
 163                         return NULL;
 164
 165                 tag = dwarf_tag(die_mem);
 166                 vr_die = die_mem;
 167         } while (tag == DW_TAG_const_type ||
 168                  tag == DW_TAG_restrict_type ||
 169                  tag == DW_TAG_volatile_type ||
 170                  tag == DW_TAG_shared_type ||
 171                  tag == DW_TAG_typedef);
 172
 173         return die_mem;
 174 }
 175
 176 static bool die_is_signed_type(Dwarf_Die *tp_die)
 177 {
 178         Dwarf_Attribute attr;
 179         Dwarf_Word ret;
 180
 181         if (dwarf_attr(tp_die, DW_AT_encoding, &attr) == NULL ||
 182             dwarf_formudata(&attr, &ret) != 0)
 183                 return false;
 184
 185         return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
 186                 ret == DW_ATE_signed_fixed);
 187 }
 188
 189 static int die_get_byte_size(Dwarf_Die *tp_die)
 190 {
 191         Dwarf_Attribute attr;
 192         Dwarf_Word ret;
 193
 194         if (dwarf_attr(tp_die, DW_AT_byte_size, &attr) == NULL ||
 195             dwarf_formudata(&attr, &ret) != 0)
 196                 return 0;
 197
 198         return (int)ret;
 199 }
 200
 201 /* Get data_member_location offset */
 202 static int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
 203 {
 204         Dwarf_Attribute attr;
 205         Dwarf_Op *expr;
 206         size_t nexpr;
 207         int ret;
 208
 209         if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
 210                 return -ENOENT;
 211
 212         if (dwarf_formudata(&attr, offs) != 0) {
 213                 /* DW_AT_data_member_location should be DW_OP_plus_uconst */
 214                 ret = dwarf_getlocation(&attr, &expr, &nexpr);
 215                 if (ret < 0 || nexpr == 0)
 216                         return -ENOENT;
 217
 218                 if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
 219                         pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
 220                                  expr[0].atom, nexpr);
 221                         return -ENOTSUP;
 222                 }
 223                 *offs = (Dwarf_Word)expr[0].number;
 224         }
 225         return 0;
 226 }
 227
 228 /* Return values for die_find callbacks */
 229 enum {
 230         DIE_FIND_CB_FOUND = 0,          /* End of Search */
 231         DIE_FIND_CB_CHILD = 1,          /* Search only children */
 232         DIE_FIND_CB_SIBLING = 2,        /* Search only siblings */
 233         DIE_FIND_CB_CONTINUE = 3,       /* Search children and siblings */
 234 };
 235
 236 /* Search a child die */
 237 static Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
 238                                  int (*callback)(Dwarf_Die *, void *),
 239                                  void *data, Dwarf_Die *die_mem)
 240 {
 241         Dwarf_Die child_die;
 242         int ret;
 243
 244         ret = dwarf_child(rt_die, die_mem);
 245         if (ret != 0)
 246                 return NULL;
 247
 248         do {
 249                 ret = callback(die_mem, data);
 250                 if (ret == DIE_FIND_CB_FOUND)
 251                         return die_mem;
 252
 253                 if ((ret & DIE_FIND_CB_CHILD) &&
 254                     die_find_child(die_mem, callback, data, &child_die)) {
 255                         memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
 256                         return die_mem;
 257                 }
 258         } while ((ret & DIE_FIND_CB_SIBLING) &&
 259                  dwarf_siblingof(die_mem, die_mem) == 0);
 260
 261         return NULL;
 262 }
 263
 264 struct __addr_die_search_param {
 265         Dwarf_Addr      addr;
 266         Dwarf_Die       *die_mem;
 267 };
 268
 269 static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
 270 {
 271         struct __addr_die_search_param *ad = data;
 272
 273         if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
 274             dwarf_haspc(fn_die, ad->addr)) {
 275                 memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
 276                 return DWARF_CB_ABORT;
 277         }
 278         return DWARF_CB_OK;
 279 }
 280
 281 /* Search a real subprogram including this line, */
 282 static Dwarf_Die *die_find_real_subprogram(Dwarf_Die *cu_die, Dwarf_Addr addr,
 283                                            Dwarf_Die *die_mem)
 284 {
 285         struct __addr_die_search_param ad;
 286         ad.addr = addr;
 287         ad.die_mem = die_mem;
 288         /* dwarf_getscopes can't find subprogram. */
 289         if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
 290                 return NULL;
 291         else
 292                 return die_mem;
 293 }
 294
 295 /* die_find callback for inline function search */
 296 static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
 297 {
 298         Dwarf_Addr *addr = data;
 299
 300         if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
 301             dwarf_haspc(die_mem, *addr))
 302                 return DIE_FIND_CB_FOUND;
 303
 304         return DIE_FIND_CB_CONTINUE;
 305 }
 306
 307 /* Similar to dwarf_getfuncs, but returns inlined_subroutine if exists. */
 308 static Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
 309                                       Dwarf_Die *die_mem)
 310 {
 311         return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
 312 }
 313
 314 static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
 315 {
 316         const char *name = data;
 317         int tag;
 318
 319         tag = dwarf_tag(die_mem);
 320         if ((tag == DW_TAG_formal_parameter ||
 321              tag == DW_TAG_variable) &&
 322             (die_compare_name(die_mem, name) == 0))
 323                 return DIE_FIND_CB_FOUND;
 324
 325         return DIE_FIND_CB_CONTINUE;
 326 }
 327
 328 /* Find a variable called 'name' */
 329 static Dwarf_Die *die_find_variable(Dwarf_Die *sp_die, const char *name,
 330                                     Dwarf_Die *die_mem)
 331 {
 332         return die_find_child(sp_die, __die_find_variable_cb, (void *)name,
 333                               die_mem);
 334 }
 335
 336 static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
 337 {
 338         const char *name = data;
 339
 340         if ((dwarf_tag(die_mem) == DW_TAG_member) &&
 341             (die_compare_name(die_mem, name) == 0))
 342                 return DIE_FIND_CB_FOUND;
 343
 344         return DIE_FIND_CB_SIBLING;
 345 }
 346
 347 /* Find a member called 'name' */
 348 static Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
 349                                   Dwarf_Die *die_mem)
 350 {
 351         return die_find_child(st_die, __die_find_member_cb, (void *)name,
 352                               die_mem);
 353 }
 354
 355 /*
 356  * Probe finder related functions
 357  */
 358
 359 /* Show a location */
 360 static int convert_location(Dwarf_Op *op, struct probe_finder *pf)
 361 {
 362         unsigned int regn;
 363         Dwarf_Word offs = 0;
 364         bool ref = false;
 365         const char *regs;
 366         struct kprobe_trace_arg *tvar = pf->tvar;
 367
 368         /* If this is based on frame buffer, set the offset */
 369         if (op->atom == DW_OP_fbreg) {
 370                 if (pf->fb_ops == NULL) {
 371                         pr_warning("The attribute of frame base is not "
 372                                    "supported.\n");
 373                         return -ENOTSUP;
 374                 }
 375                 ref = true;
 376                 offs = op->number;
 377                 op = &pf->fb_ops[0];
 378         }
 379
 380         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 381                 regn = op->atom - DW_OP_breg0;
 382                 offs += op->number;
 383                 ref = true;
 384         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 385                 regn = op->atom - DW_OP_reg0;
 386         } else if (op->atom == DW_OP_bregx) {
 387                 regn = op->number;
 388                 offs += op->number2;
 389                 ref = true;
 390         } else if (op->atom == DW_OP_regx) {
 391                 regn = op->number;
 392         } else {
 393                 pr_warning("DW_OP %x is not supported.\n", op->atom);
 394                 return -ENOTSUP;
 395         }
 396
 397         regs = get_arch_regstr(regn);
 398         if (!regs) {
 399                 pr_warning("Mapping for DWARF register number %u missing on this architecture.", regn);
 400                 return -ERANGE;
 401         }
 402
 403         tvar->value = strdup(regs);
 404         if (tvar->value == NULL)
 405                 return -ENOMEM;
 406
 407         if (ref) {
 408                 tvar->ref = zalloc(sizeof(struct kprobe_trace_arg_ref));
 409                 if (tvar->ref == NULL)
 410                         return -ENOMEM;
 411                 tvar->ref->offset = (long)offs;
 412         }
 413         return 0;
 414 }
 415
 416 static int convert_variable_type(Dwarf_Die *vr_die,
 417                                  struct kprobe_trace_arg *targ)
 418 {
 419         Dwarf_Die type;
 420         char buf[16];
 421         int ret;
 422
 423         if (die_get_real_type(vr_die, &type) == NULL) {
 424                 pr_warning("Failed to get a type information of %s.\n",
 425                            dwarf_diename(vr_die));
 426                 return -ENOENT;
 427         }
 428
 429         ret = die_get_byte_size(&type) * 8;
 430         if (ret) {
 431                 /* Check the bitwidth */
 432                 if (ret > MAX_BASIC_TYPE_BITS) {
 433                         pr_info("%s exceeds max-bitwidth."
 434                                 " Cut down to %d bits.\n",
 435                                 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 436                         ret = MAX_BASIC_TYPE_BITS;
 437                 }
 438
 439                 ret = snprintf(buf, 16, "%c%d",
 440                                die_is_signed_type(&type) ? 's' : 'u', ret);
 441                 if (ret < 0 || ret >= 16) {
 442                         if (ret >= 16)
 443                                 ret = -E2BIG;
 444                         pr_warning("Failed to convert variable type: %s\n",
 445                                    strerror(-ret));
 446                         return ret;
 447                 }
 448                 targ->type = strdup(buf);
 449                 if (targ->type == NULL)
 450                         return -ENOMEM;
 451         }
 452         return 0;
 453 }
 454
 455 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 456                                     struct perf_probe_arg_field *field,
 457                                     struct kprobe_trace_arg_ref **ref_ptr,
 458                                     Dwarf_Die *die_mem)
 459 {
 460         struct kprobe_trace_arg_ref *ref = *ref_ptr;
 461         Dwarf_Die type;
 462         Dwarf_Word offs;
 463         int ret;
 464
 465         pr_debug("converting %s in %s\n", field->name, varname);
 466         if (die_get_real_type(vr_die, &type) == NULL) {
 467                 pr_warning("Failed to get the type of %s.\n", varname);
 468                 return -ENOENT;
 469         }
 470
 471         /* Check the pointer and dereference */
 472         if (dwarf_tag(&type) == DW_TAG_pointer_type) {
 473                 if (!field->ref) {
 474                         pr_err("Semantic error: %s must be referred by '->'\n",
 475                                field->name);
 476                         return -EINVAL;
 477                 }
 478                 /* Get the type pointed by this pointer */
 479                 if (die_get_real_type(&type, &type) == NULL) {
 480                         pr_warning("Failed to get the type of %s.\n", varname);
 481                         return -ENOENT;
 482                 }
 483                 /* Verify it is a data structure  */
 484                 if (dwarf_tag(&type) != DW_TAG_structure_type) {
 485                         pr_warning("%s is not a data structure.\n", varname);
 486                         return -EINVAL;
 487                 }
 488
 489                 ref = zalloc(sizeof(struct kprobe_trace_arg_ref));
 490                 if (ref == NULL)
 491                         return -ENOMEM;
 492                 if (*ref_ptr)
 493                         (*ref_ptr)->next = ref;
 494                 else
 495                         *ref_ptr = ref;
 496         } else {
 497                 /* Verify it is a data structure  */
 498                 if (dwarf_tag(&type) != DW_TAG_structure_type) {
 499                         pr_warning("%s is not a data structure.\n", varname);
 500                         return -EINVAL;
 501                 }
 502                 if (field->ref) {
 503                         pr_err("Semantic error: %s must be referred by '.'\n",
 504                                field->name);
 505                         return -EINVAL;
 506                 }
 507                 if (!ref) {
 508                         pr_warning("Structure on a register is not "
 509                                    "supported yet.\n");
 510                         return -ENOTSUP;
 511                 }
 512         }
 513
 514         if (die_find_member(&type, field->name, die_mem) == NULL) {
 515                 pr_warning("%s(tyep:%s) has no member %s.\n", varname,
 516                            dwarf_diename(&type), field->name);
 517                 return -EINVAL;
 518         }
 519
 520         /* Get the offset of the field */
 521         ret = die_get_data_member_location(die_mem, &offs);
 522         if (ret < 0) {
 523                 pr_warning("Failed to get the offset of %s.\n", field->name);
 524                 return ret;
 525         }
 526         ref->offset += (long)offs;
 527
 528         /* Converting next field */
 529         if (field->next)
 530                 return convert_variable_fields(die_mem, field->name,
 531                                         field->next, &ref, die_mem);
 532         else
 533                 return 0;
 534 }
 535
 536 /* Show a variables in kprobe event format */
 537 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 538 {
 539         Dwarf_Attribute attr;
 540         Dwarf_Die die_mem;
 541         Dwarf_Op *expr;
 542         size_t nexpr;
 543         int ret;
 544
 545         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 546                 goto error;
 547         /* TODO: handle more than 1 exprs */
 548         ret = dwarf_getlocation_addr(&attr, pf->addr, &expr, &nexpr, 1);
 549         if (ret <= 0 || nexpr == 0)
 550                 goto error;
 551
 552         ret = convert_location(expr, pf);
 553         if (ret == 0 && pf->pvar->field) {
 554                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 555                                               pf->pvar->field, &pf->tvar->ref,
 556                                               &die_mem);
 557                 vr_die = &die_mem;
 558         }
 559         if (ret == 0) {
 560                 if (pf->pvar->type) {
 561                         pf->tvar->type = strdup(pf->pvar->type);
 562                         if (pf->tvar->type == NULL)
 563                                 ret = -ENOMEM;
 564                 } else
 565                         ret = convert_variable_type(vr_die, pf->tvar);
 566         }
 567         /* *expr will be cached in libdw. Don't free it. */
 568         return ret;
 569 error:
 570         /* TODO: Support const_value */
 571         pr_err("Failed to find the location of %s at this address.\n"
 572                " Perhaps, it has been optimized out.\n", pf->pvar->var);
 573         return -ENOENT;
 574 }
 575
 576 /* Find a variable in a subprogram die */
 577 static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 578 {
 579         Dwarf_Die vr_die;
 580         char buf[32], *ptr;
 581         int ret;
 582
 583         /* TODO: Support arrays */
 584         if (pf->pvar->name)
 585                 pf->tvar->name = strdup(pf->pvar->name);
 586         else {
 587                 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
 588                 if (ret < 0)
 589                         return ret;
 590                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 591                 if (ptr)
 592                         *ptr = '_';
 593                 pf->tvar->name = strdup(buf);
 594         }
 595         if (pf->tvar->name == NULL)
 596                 return -ENOMEM;
 597
 598         if (!is_c_varname(pf->pvar->var)) {
 599                 /* Copy raw parameters */
 600                 pf->tvar->value = strdup(pf->pvar->var);
 601                 if (pf->tvar->value == NULL)
 602                         return -ENOMEM;
 603                 else
 604                         return 0;
 605         }
 606
 607         pr_debug("Searching '%s' variable in context.\n",
 608                  pf->pvar->var);
 609         /* Search child die for local variables and parameters. */
 610         if (!die_find_variable(sp_die, pf->pvar->var, &vr_die)) {
 611                 pr_warning("Failed to find '%s' in this function.\n",
 612                            pf->pvar->var);
 613                 return -ENOENT;
 614         }
 615         return convert_variable(&vr_die, pf);
 616 }
 617
 618 /* Show a probe point to output buffer */
 619 static int convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
 620 {
 621         struct kprobe_trace_event *tev;
 622         Dwarf_Addr eaddr;
 623         Dwarf_Die die_mem;
 624         const char *name;
 625         int ret, i;
 626         Dwarf_Attribute fb_attr;
 627         size_t nops;
 628
 629         if (pf->ntevs == pf->max_tevs) {
 630                 pr_warning("Too many( > %d) probe point found.\n",
 631                            pf->max_tevs);
 632                 return -ERANGE;
 633         }
 634         tev = &pf->tevs[pf->ntevs++];
 635
 636         /* If no real subprogram, find a real one */
 637         if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
 638                 sp_die = die_find_real_subprogram(&pf->cu_die,
 639                                                  pf->addr, &die_mem);
 640                 if (!sp_die) {
 641                         pr_warning("Failed to find probe point in any "
 642                                    "functions.\n");
 643                         return -ENOENT;
 644                 }
 645         }
 646
 647         /* Copy the name of probe point */
 648         name = dwarf_diename(sp_die);
 649         if (name) {
 650                 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
 651                         pr_warning("Failed to get entry pc of %s\n",
 652                                    dwarf_diename(sp_die));
 653                         return -ENOENT;
 654                 }
 655                 tev->point.symbol = strdup(name);
 656                 if (tev->point.symbol == NULL)
 657                         return -ENOMEM;
 658                 tev->point.offset = (unsigned long)(pf->addr - eaddr);
 659         } else
 660                 /* This function has no name. */
 661                 tev->point.offset = (unsigned long)pf->addr;
 662
 663         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
 664                  tev->point.offset);
 665
 666         /* Get the frame base attribute/ops */
 667         dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
 668         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 669         if (ret <= 0 || nops == 0) {
 670                 pf->fb_ops = NULL;
 671 #if _ELFUTILS_PREREQ(0, 142)
 672         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 673                    pf->cfi != NULL) {
 674                 Dwarf_Frame *frame;
 675                 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
 676                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 677                         pr_warning("Failed to get CFA on 0x%jx\n",
 678                                    (uintmax_t)pf->addr);
 679                         return -ENOENT;
 680                 }
 681 #endif
 682         }
 683
 684         /* Find each argument */
 685         tev->nargs = pf->pev->nargs;
 686         tev->args = zalloc(sizeof(struct kprobe_trace_arg) * tev->nargs);
 687         if (tev->args == NULL)
 688                 return -ENOMEM;
 689         for (i = 0; i < pf->pev->nargs; i++) {
 690                 pf->pvar = &pf->pev->args[i];
 691                 pf->tvar = &tev->args[i];
 692                 ret = find_variable(sp_die, pf);
 693                 if (ret != 0)
 694                         return ret;
 695         }
 696
 697         /* *pf->fb_ops will be cached in libdw. Don't free it. */
 698         pf->fb_ops = NULL;
 699         return 0;
 700 }
 701
 702 /* Find probe point from its line number */
 703 static int find_probe_point_by_line(struct probe_finder *pf)
 704 {
 705         Dwarf_Lines *lines;
 706         Dwarf_Line *line;
 707         size_t nlines, i;
 708         Dwarf_Addr addr;
 709         int lineno;
 710         int ret = 0;
 711
 712         if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
 713                 pr_warning("No source lines found in this CU.\n");
 714                 return -ENOENT;
 715         }
 716
 717         for (i = 0; i < nlines && ret == 0; i++) {
 718                 line = dwarf_onesrcline(lines, i);
 719                 if (dwarf_lineno(line, &lineno) != 0 ||
 720                     lineno != pf->lno)
 721                         continue;
 722
 723                 /* TODO: Get fileno from line, but how? */
 724                 if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
 725                         continue;
 726
 727                 if (dwarf_lineaddr(line, &addr) != 0) {
 728                         pr_warning("Failed to get the address of the line.\n");
 729                         return -ENOENT;
 730                 }
 731                 pr_debug("Probe line found: line[%d]:%d addr:0x%jx\n",
 732                          (int)i, lineno, (uintmax_t)addr);
 733                 pf->addr = addr;
 734
 735                 ret = convert_probe_point(NULL, pf);
 736                 /* Continuing, because target line might be inlined. */
 737         }
 738         return ret;
 739 }
 740
 741 /* Find lines which match lazy pattern */
 742 static int find_lazy_match_lines(struct list_head *head,
 743                                  const char *fname, const char *pat)
 744 {
 745         char *fbuf, *p1, *p2;
 746         int fd, ret, line, nlines = 0;
 747         struct stat st;
 748
 749         fd = open(fname, O_RDONLY);
 750         if (fd < 0) {
 751                 pr_warning("Failed to open %s: %s\n", fname, strerror(-fd));
 752                 return fd;
 753         }
 754
 755         ret = fstat(fd, &st);
 756         if (ret < 0) {
 757                 pr_warning("Failed to get the size of %s: %s\n",
 758                            fname, strerror(errno));
 759                 return ret;
 760         }
 761         fbuf = xmalloc(st.st_size + 2);
 762         ret = read(fd, fbuf, st.st_size);
 763         if (ret < 0) {
 764                 pr_warning("Failed to read %s: %s\n", fname, strerror(errno));
 765                 return ret;
 766         }
 767         close(fd);
 768         fbuf[st.st_size] = '\n';        /* Dummy line */
 769         fbuf[st.st_size + 1] = '\0';
 770         p1 = fbuf;
 771         line = 1;
 772         while ((p2 = strchr(p1, '\n')) != NULL) {
 773                 *p2 = '\0';
 774                 if (strlazymatch(p1, pat)) {
 775                         line_list__add_line(head, line);
 776                         nlines++;
 777                 }
 778                 line++;
 779                 p1 = p2 + 1;
 780         }
 781         free(fbuf);
 782         return nlines;
 783 }
 784
 785 /* Find probe points from lazy pattern  */
 786 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 787 {
 788         Dwarf_Lines *lines;
 789         Dwarf_Line *line;
 790         size_t nlines, i;
 791         Dwarf_Addr addr;
 792         Dwarf_Die die_mem;
 793         int lineno;
 794         int ret = 0;
 795
 796         if (list_empty(&pf->lcache)) {
 797                 /* Matching lazy line pattern */
 798                 ret = find_lazy_match_lines(&pf->lcache, pf->fname,
 799                                             pf->pev->point.lazy_line);
 800                 if (ret == 0) {
 801                         pr_debug("No matched lines found in %s.\n", pf->fname);
 802                         return 0;
 803                 } else if (ret < 0)
 804                         return ret;
 805         }
 806
 807         if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
 808                 pr_warning("No source lines found in this CU.\n");
 809                 return -ENOENT;
 810         }
 811
 812         for (i = 0; i < nlines && ret >= 0; i++) {
 813                 line = dwarf_onesrcline(lines, i);
 814
 815                 if (dwarf_lineno(line, &lineno) != 0 ||
 816                     !line_list__has_line(&pf->lcache, lineno))
 817                         continue;
 818
 819                 /* TODO: Get fileno from line, but how? */
 820                 if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
 821                         continue;
 822
 823                 if (dwarf_lineaddr(line, &addr) != 0) {
 824                         pr_debug("Failed to get the address of line %d.\n",
 825                                  lineno);
 826                         continue;
 827                 }
 828                 if (sp_die) {
 829                         /* Address filtering 1: does sp_die include addr? */
 830                         if (!dwarf_haspc(sp_die, addr))
 831                                 continue;
 832                         /* Address filtering 2: No child include addr? */
 833                         if (die_find_inlinefunc(sp_die, addr, &die_mem))
 834                                 continue;
 835                 }
 836
 837                 pr_debug("Probe line found: line[%d]:%d addr:0x%llx\n",
 838                          (int)i, lineno, (unsigned long long)addr);
 839                 pf->addr = addr;
 840
 841                 ret = convert_probe_point(sp_die, pf);
 842                 /* Continuing, because target line might be inlined. */
 843         }
 844         /* TODO: deallocate lines, but how? */
 845         return ret;
 846 }
 847
 848 /* Callback parameter with return value */
 849 struct dwarf_callback_param {
 850         void *data;
 851         int retval;
 852 };
 853
 854 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 855 {
 856         struct dwarf_callback_param *param = data;
 857         struct probe_finder *pf = param->data;
 858         struct perf_probe_point *pp = &pf->pev->point;
 859         Dwarf_Addr addr;
 860
 861         if (pp->lazy_line)
 862                 param->retval = find_probe_point_lazy(in_die, pf);
 863         else {
 864                 /* Get probe address */
 865                 if (dwarf_entrypc(in_die, &addr) != 0) {
 866                         pr_warning("Failed to get entry pc of %s.\n",
 867                                    dwarf_diename(in_die));
 868                         param->retval = -ENOENT;
 869                         return DWARF_CB_ABORT;
 870                 }
 871                 pf->addr = addr;
 872                 pf->addr += pp->offset;
 873                 pr_debug("found inline addr: 0x%jx\n",
 874                          (uintmax_t)pf->addr);
 875
 876                 param->retval = convert_probe_point(in_die, pf);
 877                 if (param->retval < 0)
 878                         return DWARF_CB_ABORT;
 879         }
 880
 881         return DWARF_CB_OK;
 882 }
 883
 884 /* Search function from function name */
 885 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 886 {
 887         struct dwarf_callback_param *param = data;
 888         struct probe_finder *pf = param->data;
 889         struct perf_probe_point *pp = &pf->pev->point;
 890
 891         /* Check tag and diename */
 892         if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
 893             die_compare_name(sp_die, pp->function) != 0)
 894                 return DWARF_CB_OK;
 895
 896         pf->fname = dwarf_decl_file(sp_die);
 897         if (pp->line) { /* Function relative line */
 898                 dwarf_decl_line(sp_die, &pf->lno);
 899                 pf->lno += pp->line;
 900                 param->retval = find_probe_point_by_line(pf);
 901         } else if (!dwarf_func_inline(sp_die)) {
 902                 /* Real function */
 903                 if (pp->lazy_line)
 904                         param->retval = find_probe_point_lazy(sp_die, pf);
 905                 else {
 906                         if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
 907                                 pr_warning("Failed to get entry pc of %s.\n",
 908                                            dwarf_diename(sp_die));
 909                                 param->retval = -ENOENT;
 910                                 return DWARF_CB_ABORT;
 911                         }
 912                         pf->addr += pp->offset;
 913                         /* TODO: Check the address in this function */
 914                         param->retval = convert_probe_point(sp_die, pf);
 915                 }
 916         } else {
 917                 struct dwarf_callback_param _param = {.data = (void *)pf,
 918                                                       .retval = 0};
 919                 /* Inlined function: search instances */
 920                 dwarf_func_inline_instances(sp_die, probe_point_inline_cb,
 921                                             &_param);
 922                 param->retval = _param.retval;
 923         }
 924
 925         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
 926 }
 927
 928 static int find_probe_point_by_func(struct probe_finder *pf)
 929 {
 930         struct dwarf_callback_param _param = {.data = (void *)pf,
 931                                               .retval = 0};
 932         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
 933         return _param.retval;
 934 }
 935
 936 /* Find kprobe_trace_events specified by perf_probe_event from debuginfo */
 937 int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
 938                              struct kprobe_trace_event **tevs, int max_tevs)
 939 {
 940         struct probe_finder pf = {.pev = pev, .max_tevs = max_tevs};
 941         struct perf_probe_point *pp = &pev->point;
 942         Dwarf_Off off, noff;
 943         size_t cuhl;
 944         Dwarf_Die *diep;
 945         Dwarf *dbg;
 946         int ret = 0;
 947
 948         pf.tevs = zalloc(sizeof(struct kprobe_trace_event) * max_tevs);
 949         if (pf.tevs == NULL)
 950                 return -ENOMEM;
 951         *tevs = pf.tevs;
 952         pf.ntevs = 0;
 953
 954         dbg = dwarf_begin(fd, DWARF_C_READ);
 955         if (!dbg) {
 956                 pr_warning("No dwarf info found in the vmlinux - "
 957                         "please rebuild with CONFIG_DEBUG_INFO=y.\n");
 958                 return -EBADF;
 959         }
 960
 961 #if _ELFUTILS_PREREQ(0, 142)
 962         /* Get the call frame information from this dwarf */
 963         pf.cfi = dwarf_getcfi(dbg);
 964 #endif
 965
 966         off = 0;
 967         line_list__init(&pf.lcache);
 968         /* Loop on CUs (Compilation Unit) */
 969         while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) &&
 970                ret >= 0) {
 971                 /* Get the DIE(Debugging Information Entry) of this CU */
 972                 diep = dwarf_offdie(dbg, off + cuhl, &pf.cu_die);
 973                 if (!diep)
 974                         continue;
 975
 976                 /* Check if target file is included. */
 977                 if (pp->file)
 978                         pf.fname = cu_find_realpath(&pf.cu_die, pp->file);
 979                 else
 980                         pf.fname = NULL;
 981
 982                 if (!pp->file || pf.fname) {
 983                         if (pp->function)
 984                                 ret = find_probe_point_by_func(&pf);
 985                         else if (pp->lazy_line)
 986                                 ret = find_probe_point_lazy(NULL, &pf);
 987                         else {
 988                                 pf.lno = pp->line;
 989                                 ret = find_probe_point_by_line(&pf);
 990                         }
 991                 }
 992                 off = noff;
 993         }
 994         line_list__free(&pf.lcache);
 995         dwarf_end(dbg);
 996
 997         return (ret < 0) ? ret : pf.ntevs;
 998 }
 999
1000 /* Reverse search */
1001 int find_perf_probe_point(int fd, unsigned long addr,
1002                           struct perf_probe_point *ppt)
1003 {
1004         Dwarf_Die cudie, spdie, indie;
1005         Dwarf *dbg;
1006         Dwarf_Line *line;
1007         Dwarf_Addr laddr, eaddr;
1008         const char *tmp;
1009         int lineno, ret = 0;
1010         bool found = false;
1011
1012         dbg = dwarf_begin(fd, DWARF_C_READ);
1013         if (!dbg)
1014                 return -EBADF;
1015
1016         /* Find cu die */
1017         if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr, &cudie)) {
1018                 ret = -EINVAL;
1019                 goto end;
1020         }
1021
1022         /* Find a corresponding line */
1023         line = dwarf_getsrc_die(&cudie, (Dwarf_Addr)addr);
1024         if (line) {
1025                 if (dwarf_lineaddr(line, &laddr) == 0 &&
1026                     (Dwarf_Addr)addr == laddr &&
1027                     dwarf_lineno(line, &lineno) == 0) {
1028                         tmp = dwarf_linesrc(line, NULL, NULL);
1029                         if (tmp) {
1030                                 ppt->line = lineno;
1031                                 ppt->file = strdup(tmp);
1032                                 if (ppt->file == NULL) {
1033                                         ret = -ENOMEM;
1034                                         goto end;
1035                                 }
1036                                 found = true;
1037                         }
1038                 }
1039         }
1040
1041         /* Find a corresponding function */
1042         if (die_find_real_subprogram(&cudie, (Dwarf_Addr)addr, &spdie)) {
1043                 tmp = dwarf_diename(&spdie);
1044                 if (!tmp || dwarf_entrypc(&spdie, &eaddr) != 0)
1045                         goto end;
1046
1047                 if (ppt->line) {
1048                         if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr,
1049                                                 &indie)) {
1050                                 /* addr in an inline function */
1051                                 tmp = dwarf_diename(&indie);
1052                                 if (!tmp)
1053                                         goto end;
1054                                 ret = dwarf_decl_line(&indie, &lineno);
1055                         } else {
1056                                 if (eaddr == addr) {    /* Function entry */
1057                                         lineno = ppt->line;
1058                                         ret = 0;
1059                                 } else
1060                                         ret = dwarf_decl_line(&spdie, &lineno);
1061                         }
1062                         if (ret == 0) {
1063                                 /* Make a relative line number */
1064                                 ppt->line -= lineno;
1065                                 goto found;
1066                         }
1067                 }
1068                 /* We don't have a line number, let's use offset */
1069                 ppt->offset = addr - (unsigned long)eaddr;
1070 found:
1071                 ppt->function = strdup(tmp);
1072                 if (ppt->function == NULL) {
1073                         ret = -ENOMEM;
1074                         goto end;
1075                 }
1076                 found = true;
1077         }
1078
1079 end:
1080         dwarf_end(dbg);
1081         if (ret >= 0)
1082                 ret = found ? 1 : 0;
1083         return ret;
1084 }
1085
1086 /* Add a line and store the src path */
1087 static int line_range_add_line(const char *src, unsigned int lineno,
1088                                struct line_range *lr)
1089 {
1090         /* Copy real path */
1091         if (!lr->path) {
1092                 lr->path = strdup(src);
1093                 if (lr->path == NULL)
1094                         return -ENOMEM;
1095         }
1096         return line_list__add_line(&lr->line_list, lineno);
1097 }
1098
1099 /* Search function declaration lines */
1100 static int line_range_funcdecl_cb(Dwarf_Die *sp_die, void *data)
1101 {
1102         struct dwarf_callback_param *param = data;
1103         struct line_finder *lf = param->data;
1104         const char *src;
1105         int lineno;
1106
1107         src = dwarf_decl_file(sp_die);
1108         if (src && strtailcmp(src, lf->fname) != 0)
1109                 return DWARF_CB_OK;
1110
1111         if (dwarf_decl_line(sp_die, &lineno) != 0 ||
1112             (lf->lno_s > lineno || lf->lno_e < lineno))
1113                 return DWARF_CB_OK;
1114
1115         param->retval = line_range_add_line(src, lineno, lf->lr);
1116         if (param->retval < 0)
1117                 return DWARF_CB_ABORT;
1118         return DWARF_CB_OK;
1119 }
1120
1121 static int find_line_range_func_decl_lines(struct line_finder *lf)
1122 {
1123         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1124         dwarf_getfuncs(&lf->cu_die, line_range_funcdecl_cb, &param, 0);
1125         return param.retval;
1126 }
1127
1128 /* Find line range from its line number */
1129 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1130 {
1131         Dwarf_Lines *lines;
1132         Dwarf_Line *line;
1133         size_t nlines, i;
1134         Dwarf_Addr addr;
1135         int lineno, ret = 0;
1136         const char *src;
1137         Dwarf_Die die_mem;
1138
1139         line_list__init(&lf->lr->line_list);
1140         if (dwarf_getsrclines(&lf->cu_die, &lines, &nlines) != 0) {
1141                 pr_warning("No source lines found in this CU.\n");
1142                 return -ENOENT;
1143         }
1144
1145         /* Search probable lines on lines list */
1146         for (i = 0; i < nlines; i++) {
1147                 line = dwarf_onesrcline(lines, i);
1148                 if (dwarf_lineno(line, &lineno) != 0 ||
1149                     (lf->lno_s > lineno || lf->lno_e < lineno))
1150                         continue;
1151
1152                 if (sp_die) {
1153                         /* Address filtering 1: does sp_die include addr? */
1154                         if (dwarf_lineaddr(line, &addr) != 0 ||
1155                             !dwarf_haspc(sp_die, addr))
1156                                 continue;
1157
1158                         /* Address filtering 2: No child include addr? */
1159                         if (die_find_inlinefunc(sp_die, addr, &die_mem))
1160                                 continue;
1161                 }
1162
1163                 /* TODO: Get fileno from line, but how? */
1164                 src = dwarf_linesrc(line, NULL, NULL);
1165                 if (strtailcmp(src, lf->fname) != 0)
1166                         continue;
1167
1168                 ret = line_range_add_line(src, lineno, lf->lr);
1169                 if (ret < 0)
1170                         return ret;
1171         }
1172
1173         /*
1174          * Dwarf lines doesn't include function declarations. We have to
1175          * check functions list or given function.
1176          */
1177         if (sp_die) {
1178                 src = dwarf_decl_file(sp_die);
1179                 if (src && dwarf_decl_line(sp_die, &lineno) == 0 &&
1180                     (lf->lno_s <= lineno && lf->lno_e >= lineno))
1181                         ret = line_range_add_line(src, lineno, lf->lr);
1182         } else
1183                 ret = find_line_range_func_decl_lines(lf);
1184
1185         /* Update status */
1186         if (ret >= 0)
1187                 if (!list_empty(&lf->lr->line_list))
1188                         ret = lf->found = 1;
1189                 else
1190                         ret = 0;        /* Lines are not found */
1191         else {
1192                 free(lf->lr->path);
1193                 lf->lr->path = NULL;
1194         }
1195         return ret;
1196 }
1197
1198 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1199 {
1200         struct dwarf_callback_param *param = data;
1201
1202         param->retval = find_line_range_by_line(in_die, param->data);
1203         return DWARF_CB_ABORT;  /* No need to find other instances */
1204 }
1205
1206 /* Search function from function name */
1207 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1208 {
1209         struct dwarf_callback_param *param = data;
1210         struct line_finder *lf = param->data;
1211         struct line_range *lr = lf->lr;
1212
1213         if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
1214             die_compare_name(sp_die, lr->function) == 0) {
1215                 lf->fname = dwarf_decl_file(sp_die);
1216                 dwarf_decl_line(sp_die, &lr->offset);
1217                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1218                 lf->lno_s = lr->offset + lr->start;
1219                 if (lf->lno_s < 0)      /* Overflow */
1220                         lf->lno_s = INT_MAX;
1221                 lf->lno_e = lr->offset + lr->end;
1222                 if (lf->lno_e < 0)      /* Overflow */
1223                         lf->lno_e = INT_MAX;
1224                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1225                 lr->start = lf->lno_s;
1226                 lr->end = lf->lno_e;
1227                 if (dwarf_func_inline(sp_die)) {
1228                         struct dwarf_callback_param _param;
1229                         _param.data = (void *)lf;
1230                         _param.retval = 0;
1231                         dwarf_func_inline_instances(sp_die,
1232                                                     line_range_inline_cb,
1233                                                     &_param);
1234                         param->retval = _param.retval;
1235                 } else
1236                         param->retval = find_line_range_by_line(sp_die, lf);
1237                 return DWARF_CB_ABORT;
1238         }
1239         return DWARF_CB_OK;
1240 }
1241
1242 static int find_line_range_by_func(struct line_finder *lf)
1243 {
1244         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1245         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1246         return param.retval;
1247 }
1248
1249 int find_line_range(int fd, struct line_range *lr)
1250 {
1251         struct line_finder lf = {.lr = lr, .found = 0};
1252         int ret = 0;
1253         Dwarf_Off off = 0, noff;
1254         size_t cuhl;
1255         Dwarf_Die *diep;
1256         Dwarf *dbg;
1257
1258         dbg = dwarf_begin(fd, DWARF_C_READ);
1259         if (!dbg) {
1260                 pr_warning("No dwarf info found in the vmlinux - "
1261                         "please rebuild with CONFIG_DEBUG_INFO=y.\n");
1262                 return -EBADF;
1263         }
1264
1265         /* Loop on CUs (Compilation Unit) */
1266         while (!lf.found && ret >= 0) {
1267                 if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
1268                         break;
1269
1270                 /* Get the DIE(Debugging Information Entry) of this CU */
1271                 diep = dwarf_offdie(dbg, off + cuhl, &lf.cu_die);
1272                 if (!diep)
1273                         continue;
1274
1275                 /* Check if target file is included. */
1276                 if (lr->file)
1277                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1278                 else
1279                         lf.fname = 0;
1280
1281                 if (!lr->file || lf.fname) {
1282                         if (lr->function)
1283                                 ret = find_line_range_by_func(&lf);
1284                         else {
1285                                 lf.lno_s = lr->start;
1286                                 lf.lno_e = lr->end;
1287                                 ret = find_line_range_by_line(NULL, &lf);
1288                         }
1289                 }
1290                 off = noff;
1291         }
1292         pr_debug("path: %lx\n", (unsigned long)lr->path);
1293         dwarf_end(dbg);
1294
1295         return (ret < 0) ? ret : lf.found;
1296 }
1297