Pileus Git - ~andy/linux/blob - tools/perf/util/probe-finder.c

   1 /*
   2  * probe-finder.c : C expression to kprobe event converter
   3  *
   4  * Written by Masami Hiramatsu <mhiramat@redhat.com>
   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 <dwarf-regs.h>
  34
  35 #include <linux/bitops.h>
  36 #include "event.h"
  37 #include "debug.h"
  38 #include "util.h"
  39 #include "symbol.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 /* Line number list operations */
  46
  47 /* Add a line to line number list */
  48 static int line_list__add_line(struct list_head *head, int line)
  49 {
  50         struct line_node *ln;
  51         struct list_head *p;
  52
  53         /* Reverse search, because new line will be the last one */
  54         list_for_each_entry_reverse(ln, head, list) {
  55                 if (ln->line < line) {
  56                         p = &ln->list;
  57                         goto found;
  58                 } else if (ln->line == line)    /* Already exist */
  59                         return 1;
  60         }
  61         /* List is empty, or the smallest entry */
  62         p = head;
  63 found:
  64         pr_debug("line list: add a line %u\n", line);
  65         ln = zalloc(sizeof(struct line_node));
  66         if (ln == NULL)
  67                 return -ENOMEM;
  68         ln->line = line;
  69         INIT_LIST_HEAD(&ln->list);
  70         list_add(&ln->list, p);
  71         return 0;
  72 }
  73
  74 /* Check if the line in line number list */
  75 static int line_list__has_line(struct list_head *head, int line)
  76 {
  77         struct line_node *ln;
  78
  79         /* Reverse search, because new line will be the last one */
  80         list_for_each_entry(ln, head, list)
  81                 if (ln->line == line)
  82                         return 1;
  83
  84         return 0;
  85 }
  86
  87 /* Init line number list */
  88 static void line_list__init(struct list_head *head)
  89 {
  90         INIT_LIST_HEAD(head);
  91 }
  92
  93 /* Free line number list */
  94 static void line_list__free(struct list_head *head)
  95 {
  96         struct line_node *ln;
  97         while (!list_empty(head)) {
  98                 ln = list_first_entry(head, struct line_node, list);
  99                 list_del(&ln->list);
 100                 free(ln);
 101         }
 102 }
 103
 104 /* Dwarf FL wrappers */
 105 static char *debuginfo_path;    /* Currently dummy */
 106
 107 static const Dwfl_Callbacks offline_callbacks = {
 108         .find_debuginfo = dwfl_standard_find_debuginfo,
 109         .debuginfo_path = &debuginfo_path,
 110
 111         .section_address = dwfl_offline_section_address,
 112
 113         /* We use this table for core files too.  */
 114         .find_elf = dwfl_build_id_find_elf,
 115 };
 116
 117 /* Get a Dwarf from offline image */
 118 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
 119                                          const char *path)
 120 {
 121         int fd;
 122
 123         fd = open(path, O_RDONLY);
 124         if (fd < 0)
 125                 return fd;
 126
 127         dbg->dwfl = dwfl_begin(&offline_callbacks);
 128         if (!dbg->dwfl)
 129                 goto error;
 130
 131         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
 132         if (!dbg->mod)
 133                 goto error;
 134
 135         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
 136         if (!dbg->dbg)
 137                 goto error;
 138
 139         return 0;
 140 error:
 141         if (dbg->dwfl)
 142                 dwfl_end(dbg->dwfl);
 143         else
 144                 close(fd);
 145         memset(dbg, 0, sizeof(*dbg));
 146
 147         return -ENOENT;
 148 }
 149
 150 #if _ELFUTILS_PREREQ(0, 148)
 151 /* This method is buggy if elfutils is older than 0.148 */
 152 static int __linux_kernel_find_elf(Dwfl_Module *mod,
 153                                    void **userdata,
 154                                    const char *module_name,
 155                                    Dwarf_Addr base,
 156                                    char **file_name, Elf **elfp)
 157 {
 158         int fd;
 159         const char *path = kernel_get_module_path(module_name);
 160
 161         pr_debug2("Use file %s for %s\n", path, module_name);
 162         if (path) {
 163                 fd = open(path, O_RDONLY);
 164                 if (fd >= 0) {
 165                         *file_name = strdup(path);
 166                         return fd;
 167                 }
 168         }
 169         /* If failed, try to call standard method */
 170         return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
 171                                           file_name, elfp);
 172 }
 173
 174 static const Dwfl_Callbacks kernel_callbacks = {
 175         .find_debuginfo = dwfl_standard_find_debuginfo,
 176         .debuginfo_path = &debuginfo_path,
 177
 178         .find_elf = __linux_kernel_find_elf,
 179         .section_address = dwfl_linux_kernel_module_section_address,
 180 };
 181
 182 /* Get a Dwarf from live kernel image */
 183 static int debuginfo__init_online_kernel_dwarf(struct debuginfo *dbg,
 184                                                Dwarf_Addr addr)
 185 {
 186         dbg->dwfl = dwfl_begin(&kernel_callbacks);
 187         if (!dbg->dwfl)
 188                 return -EINVAL;
 189
 190         /* Load the kernel dwarves: Don't care the result here */
 191         dwfl_linux_kernel_report_kernel(dbg->dwfl);
 192         dwfl_linux_kernel_report_modules(dbg->dwfl);
 193
 194         dbg->dbg = dwfl_addrdwarf(dbg->dwfl, addr, &dbg->bias);
 195         /* Here, check whether we could get a real dwarf */
 196         if (!dbg->dbg) {
 197                 pr_debug("Failed to find kernel dwarf at %lx\n",
 198                          (unsigned long)addr);
 199                 dwfl_end(dbg->dwfl);
 200                 memset(dbg, 0, sizeof(*dbg));
 201                 return -ENOENT;
 202         }
 203
 204         return 0;
 205 }
 206 #else
 207 /* With older elfutils, this just support kernel module... */
 208 static int debuginfo__init_online_kernel_dwarf(struct debuginfo *dbg,
 209                                                Dwarf_Addr addr __maybe_unused)
 210 {
 211         const char *path = kernel_get_module_path("kernel");
 212
 213         if (!path) {
 214                 pr_err("Failed to find vmlinux path\n");
 215                 return -ENOENT;
 216         }
 217
 218         pr_debug2("Use file %s for debuginfo\n", path);
 219         return debuginfo__init_offline_dwarf(dbg, path);
 220 }
 221 #endif
 222
 223 struct debuginfo *debuginfo__new(const char *path)
 224 {
 225         struct debuginfo *dbg = zalloc(sizeof(*dbg));
 226         if (!dbg)
 227                 return NULL;
 228
 229         if (debuginfo__init_offline_dwarf(dbg, path) < 0) {
 230                 free(dbg);
 231                 dbg = NULL;
 232         }
 233
 234         return dbg;
 235 }
 236
 237 struct debuginfo *debuginfo__new_online_kernel(unsigned long addr)
 238 {
 239         struct debuginfo *dbg = zalloc(sizeof(*dbg));
 240
 241         if (!dbg)
 242                 return NULL;
 243
 244         if (debuginfo__init_online_kernel_dwarf(dbg, (Dwarf_Addr)addr) < 0) {
 245                 free(dbg);
 246                 dbg = NULL;
 247         }
 248
 249         return dbg;
 250 }
 251
 252 void debuginfo__delete(struct debuginfo *dbg)
 253 {
 254         if (dbg) {
 255                 if (dbg->dwfl)
 256                         dwfl_end(dbg->dwfl);
 257                 free(dbg);
 258         }
 259 }
 260
 261 /*
 262  * Probe finder related functions
 263  */
 264
 265 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 266 {
 267         struct probe_trace_arg_ref *ref;
 268         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 269         if (ref != NULL)
 270                 ref->offset = offs;
 271         return ref;
 272 }
 273
 274 /*
 275  * Convert a location into trace_arg.
 276  * If tvar == NULL, this just checks variable can be converted.
 277  * If fentry == true and vr_die is a parameter, do huristic search
 278  * for the location fuzzed by function entry mcount.
 279  */
 280 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 281                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
 282                                      struct probe_trace_arg *tvar)
 283 {
 284         Dwarf_Attribute attr;
 285         Dwarf_Addr tmp = 0;
 286         Dwarf_Op *op;
 287         size_t nops;
 288         unsigned int regn;
 289         Dwarf_Word offs = 0;
 290         bool ref = false;
 291         const char *regs;
 292         int ret;
 293
 294         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 295                 goto static_var;
 296
 297         /* TODO: handle more than 1 exprs */
 298         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 299                 return -EINVAL; /* Broken DIE ? */
 300         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 301                 ret = dwarf_entrypc(sp_die, &tmp);
 302                 if (ret || addr != tmp ||
 303                     dwarf_tag(vr_die) != DW_TAG_formal_parameter ||
 304                     dwarf_highpc(sp_die, &tmp))
 305                         return -ENOENT;
 306                 /*
 307                  * This is fuzzed by fentry mcount. We try to find the
 308                  * parameter location at the earliest address.
 309                  */
 310                 for (addr += 1; addr <= tmp; addr++) {
 311                         if (dwarf_getlocation_addr(&attr, addr, &op,
 312                                                    &nops, 1) > 0)
 313                                 goto found;
 314                 }
 315                 return -ENOENT;
 316         }
 317 found:
 318         if (nops == 0)
 319                 /* TODO: Support const_value */
 320                 return -ENOENT;
 321
 322         if (op->atom == DW_OP_addr) {
 323 static_var:
 324                 if (!tvar)
 325                         return 0;
 326                 /* Static variables on memory (not stack), make @varname */
 327                 ret = strlen(dwarf_diename(vr_die));
 328                 tvar->value = zalloc(ret + 2);
 329                 if (tvar->value == NULL)
 330                         return -ENOMEM;
 331                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 332                 tvar->ref = alloc_trace_arg_ref((long)offs);
 333                 if (tvar->ref == NULL)
 334                         return -ENOMEM;
 335                 return 0;
 336         }
 337
 338         /* If this is based on frame buffer, set the offset */
 339         if (op->atom == DW_OP_fbreg) {
 340                 if (fb_ops == NULL)
 341                         return -ENOTSUP;
 342                 ref = true;
 343                 offs = op->number;
 344                 op = &fb_ops[0];
 345         }
 346
 347         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 348                 regn = op->atom - DW_OP_breg0;
 349                 offs += op->number;
 350                 ref = true;
 351         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 352                 regn = op->atom - DW_OP_reg0;
 353         } else if (op->atom == DW_OP_bregx) {
 354                 regn = op->number;
 355                 offs += op->number2;
 356                 ref = true;
 357         } else if (op->atom == DW_OP_regx) {
 358                 regn = op->number;
 359         } else {
 360                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 361                 return -ENOTSUP;
 362         }
 363
 364         if (!tvar)
 365                 return 0;
 366
 367         regs = get_arch_regstr(regn);
 368         if (!regs) {
 369                 /* This should be a bug in DWARF or this tool */
 370                 pr_warning("Mapping for the register number %u "
 371                            "missing on this architecture.\n", regn);
 372                 return -ERANGE;
 373         }
 374
 375         tvar->value = strdup(regs);
 376         if (tvar->value == NULL)
 377                 return -ENOMEM;
 378
 379         if (ref) {
 380                 tvar->ref = alloc_trace_arg_ref((long)offs);
 381                 if (tvar->ref == NULL)
 382                         return -ENOMEM;
 383         }
 384         return 0;
 385 }
 386
 387 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 388
 389 static int convert_variable_type(Dwarf_Die *vr_die,
 390                                  struct probe_trace_arg *tvar,
 391                                  const char *cast)
 392 {
 393         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 394         Dwarf_Die type;
 395         char buf[16];
 396         int bsize, boffs, total;
 397         int ret;
 398
 399         /* TODO: check all types */
 400         if (cast && strcmp(cast, "string") != 0) {
 401                 /* Non string type is OK */
 402                 tvar->type = strdup(cast);
 403                 return (tvar->type == NULL) ? -ENOMEM : 0;
 404         }
 405
 406         bsize = dwarf_bitsize(vr_die);
 407         if (bsize > 0) {
 408                 /* This is a bitfield */
 409                 boffs = dwarf_bitoffset(vr_die);
 410                 total = dwarf_bytesize(vr_die);
 411                 if (boffs < 0 || total < 0)
 412                         return -ENOENT;
 413                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 414                                 BYTES_TO_BITS(total));
 415                 goto formatted;
 416         }
 417
 418         if (die_get_real_type(vr_die, &type) == NULL) {
 419                 pr_warning("Failed to get a type information of %s.\n",
 420                            dwarf_diename(vr_die));
 421                 return -ENOENT;
 422         }
 423
 424         pr_debug("%s type is %s.\n",
 425                  dwarf_diename(vr_die), dwarf_diename(&type));
 426
 427         if (cast && strcmp(cast, "string") == 0) {      /* String type */
 428                 ret = dwarf_tag(&type);
 429                 if (ret != DW_TAG_pointer_type &&
 430                     ret != DW_TAG_array_type) {
 431                         pr_warning("Failed to cast into string: "
 432                                    "%s(%s) is not a pointer nor array.\n",
 433                                    dwarf_diename(vr_die), dwarf_diename(&type));
 434                         return -EINVAL;
 435                 }
 436                 if (die_get_real_type(&type, &type) == NULL) {
 437                         pr_warning("Failed to get a type"
 438                                    " information.\n");
 439                         return -ENOENT;
 440                 }
 441                 if (ret == DW_TAG_pointer_type) {
 442                         while (*ref_ptr)
 443                                 ref_ptr = &(*ref_ptr)->next;
 444                         /* Add new reference with offset +0 */
 445                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 446                         if (*ref_ptr == NULL) {
 447                                 pr_warning("Out of memory error\n");
 448                                 return -ENOMEM;
 449                         }
 450                 }
 451                 if (!die_compare_name(&type, "char") &&
 452                     !die_compare_name(&type, "unsigned char")) {
 453                         pr_warning("Failed to cast into string: "
 454                                    "%s is not (unsigned) char *.\n",
 455                                    dwarf_diename(vr_die));
 456                         return -EINVAL;
 457                 }
 458                 tvar->type = strdup(cast);
 459                 return (tvar->type == NULL) ? -ENOMEM : 0;
 460         }
 461
 462         ret = dwarf_bytesize(&type);
 463         if (ret <= 0)
 464                 /* No size ... try to use default type */
 465                 return 0;
 466         ret = BYTES_TO_BITS(ret);
 467
 468         /* Check the bitwidth */
 469         if (ret > MAX_BASIC_TYPE_BITS) {
 470                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 471                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 472                 ret = MAX_BASIC_TYPE_BITS;
 473         }
 474         ret = snprintf(buf, 16, "%c%d",
 475                        die_is_signed_type(&type) ? 's' : 'u', ret);
 476
 477 formatted:
 478         if (ret < 0 || ret >= 16) {
 479                 if (ret >= 16)
 480                         ret = -E2BIG;
 481                 pr_warning("Failed to convert variable type: %s\n",
 482                            strerror(-ret));
 483                 return ret;
 484         }
 485         tvar->type = strdup(buf);
 486         if (tvar->type == NULL)
 487                 return -ENOMEM;
 488         return 0;
 489 }
 490
 491 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 492                                     struct perf_probe_arg_field *field,
 493                                     struct probe_trace_arg_ref **ref_ptr,
 494                                     Dwarf_Die *die_mem)
 495 {
 496         struct probe_trace_arg_ref *ref = *ref_ptr;
 497         Dwarf_Die type;
 498         Dwarf_Word offs;
 499         int ret, tag;
 500
 501         pr_debug("converting %s in %s\n", field->name, varname);
 502         if (die_get_real_type(vr_die, &type) == NULL) {
 503                 pr_warning("Failed to get the type of %s.\n", varname);
 504                 return -ENOENT;
 505         }
 506         pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
 507         tag = dwarf_tag(&type);
 508
 509         if (field->name[0] == '[' &&
 510             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 511                 if (field->next)
 512                         /* Save original type for next field */
 513                         memcpy(die_mem, &type, sizeof(*die_mem));
 514                 /* Get the type of this array */
 515                 if (die_get_real_type(&type, &type) == NULL) {
 516                         pr_warning("Failed to get the type of %s.\n", varname);
 517                         return -ENOENT;
 518                 }
 519                 pr_debug2("Array real type: (%x)\n",
 520                          (unsigned)dwarf_dieoffset(&type));
 521                 if (tag == DW_TAG_pointer_type) {
 522                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 523                         if (ref == NULL)
 524                                 return -ENOMEM;
 525                         if (*ref_ptr)
 526                                 (*ref_ptr)->next = ref;
 527                         else
 528                                 *ref_ptr = ref;
 529                 }
 530                 ref->offset += dwarf_bytesize(&type) * field->index;
 531                 if (!field->next)
 532                         /* Save vr_die for converting types */
 533                         memcpy(die_mem, vr_die, sizeof(*die_mem));
 534                 goto next;
 535         } else if (tag == DW_TAG_pointer_type) {
 536                 /* Check the pointer and dereference */
 537                 if (!field->ref) {
 538                         pr_err("Semantic error: %s must be referred by '->'\n",
 539                                field->name);
 540                         return -EINVAL;
 541                 }
 542                 /* Get the type pointed by this pointer */
 543                 if (die_get_real_type(&type, &type) == NULL) {
 544                         pr_warning("Failed to get the type of %s.\n", varname);
 545                         return -ENOENT;
 546                 }
 547                 /* Verify it is a data structure  */
 548                 tag = dwarf_tag(&type);
 549                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 550                         pr_warning("%s is not a data structure nor an union.\n",
 551                                    varname);
 552                         return -EINVAL;
 553                 }
 554
 555                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 556                 if (ref == NULL)
 557                         return -ENOMEM;
 558                 if (*ref_ptr)
 559                         (*ref_ptr)->next = ref;
 560                 else
 561                         *ref_ptr = ref;
 562         } else {
 563                 /* Verify it is a data structure  */
 564                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 565                         pr_warning("%s is not a data structure nor an union.\n",
 566                                    varname);
 567                         return -EINVAL;
 568                 }
 569                 if (field->name[0] == '[') {
 570                         pr_err("Semantic error: %s is not a pointor"
 571                                " nor array.\n", varname);
 572                         return -EINVAL;
 573                 }
 574                 if (field->ref) {
 575                         pr_err("Semantic error: %s must be referred by '.'\n",
 576                                field->name);
 577                         return -EINVAL;
 578                 }
 579                 if (!ref) {
 580                         pr_warning("Structure on a register is not "
 581                                    "supported yet.\n");
 582                         return -ENOTSUP;
 583                 }
 584         }
 585
 586         if (die_find_member(&type, field->name, die_mem) == NULL) {
 587                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 588                            dwarf_diename(&type), field->name);
 589                 return -EINVAL;
 590         }
 591
 592         /* Get the offset of the field */
 593         if (tag == DW_TAG_union_type) {
 594                 offs = 0;
 595         } else {
 596                 ret = die_get_data_member_location(die_mem, &offs);
 597                 if (ret < 0) {
 598                         pr_warning("Failed to get the offset of %s.\n",
 599                                    field->name);
 600                         return ret;
 601                 }
 602         }
 603         ref->offset += (long)offs;
 604
 605 next:
 606         /* Converting next field */
 607         if (field->next)
 608                 return convert_variable_fields(die_mem, field->name,
 609                                         field->next, &ref, die_mem);
 610         else
 611                 return 0;
 612 }
 613
 614 /* Show a variables in kprobe event format */
 615 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 616 {
 617         Dwarf_Die die_mem;
 618         int ret;
 619
 620         pr_debug("Converting variable %s into trace event.\n",
 621                  dwarf_diename(vr_die));
 622
 623         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 624                                         &pf->sp_die, pf->tvar);
 625         if (ret == -ENOENT)
 626                 pr_err("Failed to find the location of %s at this address.\n"
 627                        " Perhaps, it has been optimized out.\n", pf->pvar->var);
 628         else if (ret == -ENOTSUP)
 629                 pr_err("Sorry, we don't support this variable location yet.\n");
 630         else if (pf->pvar->field) {
 631                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 632                                               pf->pvar->field, &pf->tvar->ref,
 633                                               &die_mem);
 634                 vr_die = &die_mem;
 635         }
 636         if (ret == 0)
 637                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
 638         /* *expr will be cached in libdw. Don't free it. */
 639         return ret;
 640 }
 641
 642 /* Find a variable in a scope DIE */
 643 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 644 {
 645         Dwarf_Die vr_die;
 646         char buf[32], *ptr;
 647         int ret = 0;
 648
 649         if (!is_c_varname(pf->pvar->var)) {
 650                 /* Copy raw parameters */
 651                 pf->tvar->value = strdup(pf->pvar->var);
 652                 if (pf->tvar->value == NULL)
 653                         return -ENOMEM;
 654                 if (pf->pvar->type) {
 655                         pf->tvar->type = strdup(pf->pvar->type);
 656                         if (pf->tvar->type == NULL)
 657                                 return -ENOMEM;
 658                 }
 659                 if (pf->pvar->name) {
 660                         pf->tvar->name = strdup(pf->pvar->name);
 661                         if (pf->tvar->name == NULL)
 662                                 return -ENOMEM;
 663                 } else
 664                         pf->tvar->name = NULL;
 665                 return 0;
 666         }
 667
 668         if (pf->pvar->name)
 669                 pf->tvar->name = strdup(pf->pvar->name);
 670         else {
 671                 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
 672                 if (ret < 0)
 673                         return ret;
 674                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 675                 if (ptr)
 676                         *ptr = '_';
 677                 pf->tvar->name = strdup(buf);
 678         }
 679         if (pf->tvar->name == NULL)
 680                 return -ENOMEM;
 681
 682         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 683         /* Search child die for local variables and parameters. */
 684         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 685                 /* Search again in global variables */
 686                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die))
 687                         ret = -ENOENT;
 688         }
 689         if (ret >= 0)
 690                 ret = convert_variable(&vr_die, pf);
 691
 692         if (ret < 0)
 693                 pr_warning("Failed to find '%s' in this function.\n",
 694                            pf->pvar->var);
 695         return ret;
 696 }
 697
 698 /* Convert subprogram DIE to trace point */
 699 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 700                                   Dwarf_Addr paddr, bool retprobe,
 701                                   struct probe_trace_point *tp)
 702 {
 703         Dwarf_Addr eaddr, highaddr;
 704         GElf_Sym sym;
 705         const char *symbol;
 706
 707         /* Verify the address is correct */
 708         if (dwarf_entrypc(sp_die, &eaddr) != 0) {
 709                 pr_warning("Failed to get entry address of %s\n",
 710                            dwarf_diename(sp_die));
 711                 return -ENOENT;
 712         }
 713         if (dwarf_highpc(sp_die, &highaddr) != 0) {
 714                 pr_warning("Failed to get end address of %s\n",
 715                            dwarf_diename(sp_die));
 716                 return -ENOENT;
 717         }
 718         if (paddr > highaddr) {
 719                 pr_warning("Offset specified is greater than size of %s\n",
 720                            dwarf_diename(sp_die));
 721                 return -EINVAL;
 722         }
 723
 724         /* Get an appropriate symbol from symtab */
 725         symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 726         if (!symbol) {
 727                 pr_warning("Failed to find symbol at 0x%lx\n",
 728                            (unsigned long)paddr);
 729                 return -ENOENT;
 730         }
 731         tp->offset = (unsigned long)(paddr - sym.st_value);
 732         tp->symbol = strdup(symbol);
 733         if (!tp->symbol)
 734                 return -ENOMEM;
 735
 736         /* Return probe must be on the head of a subprogram */
 737         if (retprobe) {
 738                 if (eaddr != paddr) {
 739                         pr_warning("Return probe must be on the head of"
 740                                    " a real function.\n");
 741                         return -EINVAL;
 742                 }
 743                 tp->retprobe = true;
 744         }
 745
 746         return 0;
 747 }
 748
 749 /* Call probe_finder callback with scope DIE */
 750 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 751 {
 752         Dwarf_Attribute fb_attr;
 753         size_t nops;
 754         int ret;
 755
 756         if (!sc_die) {
 757                 pr_err("Caller must pass a scope DIE. Program error.\n");
 758                 return -EINVAL;
 759         }
 760
 761         /* If not a real subprogram, find a real one */
 762         if (!die_is_func_def(sc_die)) {
 763                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 764                         pr_warning("Failed to find probe point in any "
 765                                    "functions.\n");
 766                         return -ENOENT;
 767                 }
 768         } else
 769                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 770
 771         /* Get the frame base attribute/ops from subprogram */
 772         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 773         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 774         if (ret <= 0 || nops == 0) {
 775                 pf->fb_ops = NULL;
 776 #if _ELFUTILS_PREREQ(0, 142)
 777         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 778                    pf->cfi != NULL) {
 779                 Dwarf_Frame *frame;
 780                 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
 781                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 782                         pr_warning("Failed to get call frame on 0x%jx\n",
 783                                    (uintmax_t)pf->addr);
 784                         return -ENOENT;
 785                 }
 786 #endif
 787         }
 788
 789         /* Call finder's callback handler */
 790         ret = pf->callback(sc_die, pf);
 791
 792         /* *pf->fb_ops will be cached in libdw. Don't free it. */
 793         pf->fb_ops = NULL;
 794
 795         return ret;
 796 }
 797
 798 struct find_scope_param {
 799         const char *function;
 800         const char *file;
 801         int line;
 802         int diff;
 803         Dwarf_Die *die_mem;
 804         bool found;
 805 };
 806
 807 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 808 {
 809         struct find_scope_param *fsp = data;
 810         const char *file;
 811         int lno;
 812
 813         /* Skip if declared file name does not match */
 814         if (fsp->file) {
 815                 file = dwarf_decl_file(fn_die);
 816                 if (!file || strcmp(fsp->file, file) != 0)
 817                         return 0;
 818         }
 819         /* If the function name is given, that's what user expects */
 820         if (fsp->function) {
 821                 if (die_compare_name(fn_die, fsp->function)) {
 822                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 823                         fsp->found = true;
 824                         return 1;
 825                 }
 826         } else {
 827                 /* With the line number, find the nearest declared DIE */
 828                 dwarf_decl_line(fn_die, &lno);
 829                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 830                         /* Keep a candidate and continue */
 831                         fsp->diff = fsp->line - lno;
 832                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 833                         fsp->found = true;
 834                 }
 835         }
 836         return 0;
 837 }
 838
 839 /* Find an appropriate scope fits to given conditions */
 840 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 841 {
 842         struct find_scope_param fsp = {
 843                 .function = pf->pev->point.function,
 844                 .file = pf->fname,
 845                 .line = pf->lno,
 846                 .diff = INT_MAX,
 847                 .die_mem = die_mem,
 848                 .found = false,
 849         };
 850
 851         cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
 852
 853         return fsp.found ? die_mem : NULL;
 854 }
 855
 856 static int probe_point_line_walker(const char *fname, int lineno,
 857                                    Dwarf_Addr addr, void *data)
 858 {
 859         struct probe_finder *pf = data;
 860         Dwarf_Die *sc_die, die_mem;
 861         int ret;
 862
 863         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 864                 return 0;
 865
 866         pf->addr = addr;
 867         sc_die = find_best_scope(pf, &die_mem);
 868         if (!sc_die) {
 869                 pr_warning("Failed to find scope of probe point.\n");
 870                 return -ENOENT;
 871         }
 872
 873         ret = call_probe_finder(sc_die, pf);
 874
 875         /* Continue if no error, because the line will be in inline function */
 876         return ret < 0 ? ret : 0;
 877 }
 878
 879 /* Find probe point from its line number */
 880 static int find_probe_point_by_line(struct probe_finder *pf)
 881 {
 882         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 883 }
 884
 885 /* Find lines which match lazy pattern */
 886 static int find_lazy_match_lines(struct list_head *head,
 887                                  const char *fname, const char *pat)
 888 {
 889         FILE *fp;
 890         char *line = NULL;
 891         size_t line_len;
 892         ssize_t len;
 893         int count = 0, linenum = 1;
 894
 895         fp = fopen(fname, "r");
 896         if (!fp) {
 897                 pr_warning("Failed to open %s: %s\n", fname, strerror(errno));
 898                 return -errno;
 899         }
 900
 901         while ((len = getline(&line, &line_len, fp)) > 0) {
 902
 903                 if (line[len - 1] == '\n')
 904                         line[len - 1] = '\0';
 905
 906                 if (strlazymatch(line, pat)) {
 907                         line_list__add_line(head, linenum);
 908                         count++;
 909                 }
 910                 linenum++;
 911         }
 912
 913         if (ferror(fp))
 914                 count = -errno;
 915         free(line);
 916         fclose(fp);
 917
 918         if (count == 0)
 919                 pr_debug("No matched lines found in %s.\n", fname);
 920         return count;
 921 }
 922
 923 static int probe_point_lazy_walker(const char *fname, int lineno,
 924                                    Dwarf_Addr addr, void *data)
 925 {
 926         struct probe_finder *pf = data;
 927         Dwarf_Die *sc_die, die_mem;
 928         int ret;
 929
 930         if (!line_list__has_line(&pf->lcache, lineno) ||
 931             strtailcmp(fname, pf->fname) != 0)
 932                 return 0;
 933
 934         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 935                  lineno, (unsigned long long)addr);
 936         pf->addr = addr;
 937         pf->lno = lineno;
 938         sc_die = find_best_scope(pf, &die_mem);
 939         if (!sc_die) {
 940                 pr_warning("Failed to find scope of probe point.\n");
 941                 return -ENOENT;
 942         }
 943
 944         ret = call_probe_finder(sc_die, pf);
 945
 946         /*
 947          * Continue if no error, because the lazy pattern will match
 948          * to other lines
 949          */
 950         return ret < 0 ? ret : 0;
 951 }
 952
 953 /* Find probe points from lazy pattern  */
 954 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 955 {
 956         int ret = 0;
 957
 958         if (list_empty(&pf->lcache)) {
 959                 /* Matching lazy line pattern */
 960                 ret = find_lazy_match_lines(&pf->lcache, pf->fname,
 961                                             pf->pev->point.lazy_line);
 962                 if (ret <= 0)
 963                         return ret;
 964         }
 965
 966         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 967 }
 968
 969 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 970 {
 971         struct probe_finder *pf = data;
 972         struct perf_probe_point *pp = &pf->pev->point;
 973         Dwarf_Addr addr;
 974         int ret;
 975
 976         if (pp->lazy_line)
 977                 ret = find_probe_point_lazy(in_die, pf);
 978         else {
 979                 /* Get probe address */
 980                 if (dwarf_entrypc(in_die, &addr) != 0) {
 981                         pr_warning("Failed to get entry address of %s.\n",
 982                                    dwarf_diename(in_die));
 983                         return -ENOENT;
 984                 }
 985                 pf->addr = addr;
 986                 pf->addr += pp->offset;
 987                 pr_debug("found inline addr: 0x%jx\n",
 988                          (uintmax_t)pf->addr);
 989
 990                 ret = call_probe_finder(in_die, pf);
 991         }
 992
 993         return ret;
 994 }
 995
 996 /* Callback parameter with return value for libdw */
 997 struct dwarf_callback_param {
 998         void *data;
 999         int retval;
1000 };
1001
1002 /* Search function from function name */
1003 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
1004 {
1005         struct dwarf_callback_param *param = data;
1006         struct probe_finder *pf = param->data;
1007         struct perf_probe_point *pp = &pf->pev->point;
1008
1009         /* Check tag and diename */
1010         if (!die_is_func_def(sp_die) ||
1011             !die_compare_name(sp_die, pp->function))
1012                 return DWARF_CB_OK;
1013
1014         /* Check declared file */
1015         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
1016                 return DWARF_CB_OK;
1017
1018         pf->fname = dwarf_decl_file(sp_die);
1019         if (pp->line) { /* Function relative line */
1020                 dwarf_decl_line(sp_die, &pf->lno);
1021                 pf->lno += pp->line;
1022                 param->retval = find_probe_point_by_line(pf);
1023         } else if (!dwarf_func_inline(sp_die)) {
1024                 /* Real function */
1025                 if (pp->lazy_line)
1026                         param->retval = find_probe_point_lazy(sp_die, pf);
1027                 else {
1028                         if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
1029                                 pr_warning("Failed to get entry address of "
1030                                            "%s.\n", dwarf_diename(sp_die));
1031                                 param->retval = -ENOENT;
1032                                 return DWARF_CB_ABORT;
1033                         }
1034                         pf->addr += pp->offset;
1035                         /* TODO: Check the address in this function */
1036                         param->retval = call_probe_finder(sp_die, pf);
1037                 }
1038         } else
1039                 /* Inlined function: search instances */
1040                 param->retval = die_walk_instances(sp_die,
1041                                         probe_point_inline_cb, (void *)pf);
1042
1043         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1044 }
1045
1046 static int find_probe_point_by_func(struct probe_finder *pf)
1047 {
1048         struct dwarf_callback_param _param = {.data = (void *)pf,
1049                                               .retval = 0};
1050         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1051         return _param.retval;
1052 }
1053
1054 struct pubname_callback_param {
1055         char *function;
1056         char *file;
1057         Dwarf_Die *cu_die;
1058         Dwarf_Die *sp_die;
1059         int found;
1060 };
1061
1062 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1063 {
1064         struct pubname_callback_param *param = data;
1065
1066         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1067                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1068                         return DWARF_CB_OK;
1069
1070                 if (die_compare_name(param->sp_die, param->function)) {
1071                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1072                                 return DWARF_CB_OK;
1073
1074                         if (param->file &&
1075                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1076                                 return DWARF_CB_OK;
1077
1078                         param->found = 1;
1079                         return DWARF_CB_ABORT;
1080                 }
1081         }
1082
1083         return DWARF_CB_OK;
1084 }
1085
1086 /* Find probe points from debuginfo */
1087 static int debuginfo__find_probes(struct debuginfo *dbg,
1088                                   struct probe_finder *pf)
1089 {
1090         struct perf_probe_point *pp = &pf->pev->point;
1091         Dwarf_Off off, noff;
1092         size_t cuhl;
1093         Dwarf_Die *diep;
1094         int ret = 0;
1095
1096 #if _ELFUTILS_PREREQ(0, 142)
1097         /* Get the call frame information from this dwarf */
1098         pf->cfi = dwarf_getcfi(dbg->dbg);
1099 #endif
1100
1101         off = 0;
1102         line_list__init(&pf->lcache);
1103
1104         /* Fastpath: lookup by function name from .debug_pubnames section */
1105         if (pp->function) {
1106                 struct pubname_callback_param pubname_param = {
1107                         .function = pp->function,
1108                         .file     = pp->file,
1109                         .cu_die   = &pf->cu_die,
1110                         .sp_die   = &pf->sp_die,
1111                         .found    = 0,
1112                 };
1113                 struct dwarf_callback_param probe_param = {
1114                         .data = pf,
1115                 };
1116
1117                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1118                                   &pubname_param, 0);
1119                 if (pubname_param.found) {
1120                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1121                         if (ret)
1122                                 goto found;
1123                 }
1124         }
1125
1126         /* Loop on CUs (Compilation Unit) */
1127         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1128                 /* Get the DIE(Debugging Information Entry) of this CU */
1129                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1130                 if (!diep)
1131                         continue;
1132
1133                 /* Check if target file is included. */
1134                 if (pp->file)
1135                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1136                 else
1137                         pf->fname = NULL;
1138
1139                 if (!pp->file || pf->fname) {
1140                         if (pp->function)
1141                                 ret = find_probe_point_by_func(pf);
1142                         else if (pp->lazy_line)
1143                                 ret = find_probe_point_lazy(NULL, pf);
1144                         else {
1145                                 pf->lno = pp->line;
1146                                 ret = find_probe_point_by_line(pf);
1147                         }
1148                         if (ret < 0)
1149                                 break;
1150                 }
1151                 off = noff;
1152         }
1153
1154 found:
1155         line_list__free(&pf->lcache);
1156
1157         return ret;
1158 }
1159
1160 struct local_vars_finder {
1161         struct probe_finder *pf;
1162         struct perf_probe_arg *args;
1163         int max_args;
1164         int nargs;
1165         int ret;
1166 };
1167
1168 /* Collect available variables in this scope */
1169 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1170 {
1171         struct local_vars_finder *vf = data;
1172         struct probe_finder *pf = vf->pf;
1173         int tag;
1174
1175         tag = dwarf_tag(die_mem);
1176         if (tag == DW_TAG_formal_parameter ||
1177             tag == DW_TAG_variable) {
1178                 if (convert_variable_location(die_mem, vf->pf->addr,
1179                                               vf->pf->fb_ops, &pf->sp_die,
1180                                               NULL) == 0) {
1181                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1182                         if (vf->args[vf->nargs].var == NULL) {
1183                                 vf->ret = -ENOMEM;
1184                                 return DIE_FIND_CB_END;
1185                         }
1186                         pr_debug(" %s", vf->args[vf->nargs].var);
1187                         vf->nargs++;
1188                 }
1189         }
1190
1191         if (dwarf_haspc(die_mem, vf->pf->addr))
1192                 return DIE_FIND_CB_CONTINUE;
1193         else
1194                 return DIE_FIND_CB_SIBLING;
1195 }
1196
1197 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1198                              struct perf_probe_arg *args)
1199 {
1200         Dwarf_Die die_mem;
1201         int i;
1202         int n = 0;
1203         struct local_vars_finder vf = {.pf = pf, .args = args,
1204                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1205
1206         for (i = 0; i < pf->pev->nargs; i++) {
1207                 /* var never be NULL */
1208                 if (strcmp(pf->pev->args[i].var, "$vars") == 0) {
1209                         pr_debug("Expanding $vars into:");
1210                         vf.nargs = n;
1211                         /* Special local variables */
1212                         die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1213                                        &die_mem);
1214                         pr_debug(" (%d)\n", vf.nargs - n);
1215                         if (vf.ret < 0)
1216                                 return vf.ret;
1217                         n = vf.nargs;
1218                 } else {
1219                         /* Copy normal argument */
1220                         args[n] = pf->pev->args[i];
1221                         n++;
1222                 }
1223         }
1224         return n;
1225 }
1226
1227 /* Add a found probe point into trace event list */
1228 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1229 {
1230         struct trace_event_finder *tf =
1231                         container_of(pf, struct trace_event_finder, pf);
1232         struct probe_trace_event *tev;
1233         struct perf_probe_arg *args;
1234         int ret, i;
1235
1236         /* Check number of tevs */
1237         if (tf->ntevs == tf->max_tevs) {
1238                 pr_warning("Too many( > %d) probe point found.\n",
1239                            tf->max_tevs);
1240                 return -ERANGE;
1241         }
1242         tev = &tf->tevs[tf->ntevs++];
1243
1244         /* Trace point should be converted from subprogram DIE */
1245         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1246                                      pf->pev->point.retprobe, &tev->point);
1247         if (ret < 0)
1248                 return ret;
1249
1250         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1251                  tev->point.offset);
1252
1253         /* Expand special probe argument if exist */
1254         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1255         if (args == NULL)
1256                 return -ENOMEM;
1257
1258         ret = expand_probe_args(sc_die, pf, args);
1259         if (ret < 0)
1260                 goto end;
1261
1262         tev->nargs = ret;
1263         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1264         if (tev->args == NULL) {
1265                 ret = -ENOMEM;
1266                 goto end;
1267         }
1268
1269         /* Find each argument */
1270         for (i = 0; i < tev->nargs; i++) {
1271                 pf->pvar = &args[i];
1272                 pf->tvar = &tev->args[i];
1273                 /* Variable should be found from scope DIE */
1274                 ret = find_variable(sc_die, pf);
1275                 if (ret != 0)
1276                         break;
1277         }
1278
1279 end:
1280         free(args);
1281         return ret;
1282 }
1283
1284 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1285 int debuginfo__find_trace_events(struct debuginfo *dbg,
1286                                  struct perf_probe_event *pev,
1287                                  struct probe_trace_event **tevs, int max_tevs)
1288 {
1289         struct trace_event_finder tf = {
1290                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1291                         .mod = dbg->mod, .max_tevs = max_tevs};
1292         int ret;
1293
1294         /* Allocate result tevs array */
1295         *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
1296         if (*tevs == NULL)
1297                 return -ENOMEM;
1298
1299         tf.tevs = *tevs;
1300         tf.ntevs = 0;
1301
1302         ret = debuginfo__find_probes(dbg, &tf.pf);
1303         if (ret < 0) {
1304                 free(*tevs);
1305                 *tevs = NULL;
1306                 return ret;
1307         }
1308
1309         return (ret < 0) ? ret : tf.ntevs;
1310 }
1311
1312 #define MAX_VAR_LEN 64
1313
1314 /* Collect available variables in this scope */
1315 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1316 {
1317         struct available_var_finder *af = data;
1318         struct variable_list *vl;
1319         char buf[MAX_VAR_LEN];
1320         int tag, ret;
1321
1322         vl = &af->vls[af->nvls - 1];
1323
1324         tag = dwarf_tag(die_mem);
1325         if (tag == DW_TAG_formal_parameter ||
1326             tag == DW_TAG_variable) {
1327                 ret = convert_variable_location(die_mem, af->pf.addr,
1328                                                 af->pf.fb_ops, &af->pf.sp_die,
1329                                                 NULL);
1330                 if (ret == 0) {
1331                         ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1332                         pr_debug2("Add new var: %s\n", buf);
1333                         if (ret > 0)
1334                                 strlist__add(vl->vars, buf);
1335                 }
1336         }
1337
1338         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1339                 return DIE_FIND_CB_CONTINUE;
1340         else
1341                 return DIE_FIND_CB_SIBLING;
1342 }
1343
1344 /* Add a found vars into available variables list */
1345 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1346 {
1347         struct available_var_finder *af =
1348                         container_of(pf, struct available_var_finder, pf);
1349         struct variable_list *vl;
1350         Dwarf_Die die_mem;
1351         int ret;
1352
1353         /* Check number of tevs */
1354         if (af->nvls == af->max_vls) {
1355                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1356                 return -ERANGE;
1357         }
1358         vl = &af->vls[af->nvls++];
1359
1360         /* Trace point should be converted from subprogram DIE */
1361         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1362                                      pf->pev->point.retprobe, &vl->point);
1363         if (ret < 0)
1364                 return ret;
1365
1366         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1367                  vl->point.offset);
1368
1369         /* Find local variables */
1370         vl->vars = strlist__new(true, NULL);
1371         if (vl->vars == NULL)
1372                 return -ENOMEM;
1373         af->child = true;
1374         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1375
1376         /* Find external variables */
1377         if (!af->externs)
1378                 goto out;
1379         /* Don't need to search child DIE for externs. */
1380         af->child = false;
1381         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1382
1383 out:
1384         if (strlist__empty(vl->vars)) {
1385                 strlist__delete(vl->vars);
1386                 vl->vars = NULL;
1387         }
1388
1389         return ret;
1390 }
1391
1392 /* Find available variables at given probe point */
1393 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1394                                       struct perf_probe_event *pev,
1395                                       struct variable_list **vls,
1396                                       int max_vls, bool externs)
1397 {
1398         struct available_var_finder af = {
1399                         .pf = {.pev = pev, .callback = add_available_vars},
1400                         .mod = dbg->mod,
1401                         .max_vls = max_vls, .externs = externs};
1402         int ret;
1403
1404         /* Allocate result vls array */
1405         *vls = zalloc(sizeof(struct variable_list) * max_vls);
1406         if (*vls == NULL)
1407                 return -ENOMEM;
1408
1409         af.vls = *vls;
1410         af.nvls = 0;
1411
1412         ret = debuginfo__find_probes(dbg, &af.pf);
1413         if (ret < 0) {
1414                 /* Free vlist for error */
1415                 while (af.nvls--) {
1416                         if (af.vls[af.nvls].point.symbol)
1417                                 free(af.vls[af.nvls].point.symbol);
1418                         if (af.vls[af.nvls].vars)
1419                                 strlist__delete(af.vls[af.nvls].vars);
1420                 }
1421                 free(af.vls);
1422                 *vls = NULL;
1423                 return ret;
1424         }
1425
1426         return (ret < 0) ? ret : af.nvls;
1427 }
1428
1429 /* Reverse search */
1430 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1431                                 struct perf_probe_point *ppt)
1432 {
1433         Dwarf_Die cudie, spdie, indie;
1434         Dwarf_Addr _addr = 0, baseaddr = 0;
1435         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1436         int baseline = 0, lineno = 0, ret = 0;
1437
1438         /* Adjust address with bias */
1439         addr += dbg->bias;
1440
1441         /* Find cu die */
1442         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr - dbg->bias, &cudie)) {
1443                 pr_warning("Failed to find debug information for address %lx\n",
1444                            addr);
1445                 ret = -EINVAL;
1446                 goto end;
1447         }
1448
1449         /* Find a corresponding line (filename and lineno) */
1450         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1451         /* Don't care whether it failed or not */
1452
1453         /* Find a corresponding function (name, baseline and baseaddr) */
1454         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1455                 /* Get function entry information */
1456                 func = basefunc = dwarf_diename(&spdie);
1457                 if (!func ||
1458                     dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1459                     dwarf_decl_line(&spdie, &baseline) != 0) {
1460                         lineno = 0;
1461                         goto post;
1462                 }
1463
1464                 fname = dwarf_decl_file(&spdie);
1465                 if (addr == (unsigned long)baseaddr) {
1466                         /* Function entry - Relative line number is 0 */
1467                         lineno = baseline;
1468                         goto post;
1469                 }
1470
1471                 /* Track down the inline functions step by step */
1472                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1473                                                 &indie)) {
1474                         /* There is an inline function */
1475                         if (dwarf_entrypc(&indie, &_addr) == 0 &&
1476                             _addr == addr) {
1477                                 /*
1478                                  * addr is at an inline function entry.
1479                                  * In this case, lineno should be the call-site
1480                                  * line number. (overwrite lineinfo)
1481                                  */
1482                                 lineno = die_get_call_lineno(&indie);
1483                                 fname = die_get_call_file(&indie);
1484                                 break;
1485                         } else {
1486                                 /*
1487                                  * addr is in an inline function body.
1488                                  * Since lineno points one of the lines
1489                                  * of the inline function, baseline should
1490                                  * be the entry line of the inline function.
1491                                  */
1492                                 tmp = dwarf_diename(&indie);
1493                                 if (!tmp ||
1494                                     dwarf_decl_line(&indie, &baseline) != 0)
1495                                         break;
1496                                 func = tmp;
1497                                 spdie = indie;
1498                         }
1499                 }
1500                 /* Verify the lineno and baseline are in a same file */
1501                 tmp = dwarf_decl_file(&spdie);
1502                 if (!tmp || strcmp(tmp, fname) != 0)
1503                         lineno = 0;
1504         }
1505
1506 post:
1507         /* Make a relative line number or an offset */
1508         if (lineno)
1509                 ppt->line = lineno - baseline;
1510         else if (basefunc) {
1511                 ppt->offset = addr - (unsigned long)baseaddr;
1512                 func = basefunc;
1513         }
1514
1515         /* Duplicate strings */
1516         if (func) {
1517                 ppt->function = strdup(func);
1518                 if (ppt->function == NULL) {
1519                         ret = -ENOMEM;
1520                         goto end;
1521                 }
1522         }
1523         if (fname) {
1524                 ppt->file = strdup(fname);
1525                 if (ppt->file == NULL) {
1526                         if (ppt->function) {
1527                                 free(ppt->function);
1528                                 ppt->function = NULL;
1529                         }
1530                         ret = -ENOMEM;
1531                         goto end;
1532                 }
1533         }
1534 end:
1535         if (ret == 0 && (fname || func))
1536                 ret = 1;        /* Found a point */
1537         return ret;
1538 }
1539
1540 /* Add a line and store the src path */
1541 static int line_range_add_line(const char *src, unsigned int lineno,
1542                                struct line_range *lr)
1543 {
1544         /* Copy source path */
1545         if (!lr->path) {
1546                 lr->path = strdup(src);
1547                 if (lr->path == NULL)
1548                         return -ENOMEM;
1549         }
1550         return line_list__add_line(&lr->line_list, lineno);
1551 }
1552
1553 static int line_range_walk_cb(const char *fname, int lineno,
1554                               Dwarf_Addr addr __maybe_unused,
1555                               void *data)
1556 {
1557         struct line_finder *lf = data;
1558
1559         if ((strtailcmp(fname, lf->fname) != 0) ||
1560             (lf->lno_s > lineno || lf->lno_e < lineno))
1561                 return 0;
1562
1563         if (line_range_add_line(fname, lineno, lf->lr) < 0)
1564                 return -EINVAL;
1565
1566         return 0;
1567 }
1568
1569 /* Find line range from its line number */
1570 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1571 {
1572         int ret;
1573
1574         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1575
1576         /* Update status */
1577         if (ret >= 0)
1578                 if (!list_empty(&lf->lr->line_list))
1579                         ret = lf->found = 1;
1580                 else
1581                         ret = 0;        /* Lines are not found */
1582         else {
1583                 free(lf->lr->path);
1584                 lf->lr->path = NULL;
1585         }
1586         return ret;
1587 }
1588
1589 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1590 {
1591         find_line_range_by_line(in_die, data);
1592
1593         /*
1594          * We have to check all instances of inlined function, because
1595          * some execution paths can be optimized out depends on the
1596          * function argument of instances
1597          */
1598         return 0;
1599 }
1600
1601 /* Search function definition from function name */
1602 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1603 {
1604         struct dwarf_callback_param *param = data;
1605         struct line_finder *lf = param->data;
1606         struct line_range *lr = lf->lr;
1607
1608         /* Check declared file */
1609         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1610                 return DWARF_CB_OK;
1611
1612         if (die_is_func_def(sp_die) &&
1613             die_compare_name(sp_die, lr->function)) {
1614                 lf->fname = dwarf_decl_file(sp_die);
1615                 dwarf_decl_line(sp_die, &lr->offset);
1616                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1617                 lf->lno_s = lr->offset + lr->start;
1618                 if (lf->lno_s < 0)      /* Overflow */
1619                         lf->lno_s = INT_MAX;
1620                 lf->lno_e = lr->offset + lr->end;
1621                 if (lf->lno_e < 0)      /* Overflow */
1622                         lf->lno_e = INT_MAX;
1623                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1624                 lr->start = lf->lno_s;
1625                 lr->end = lf->lno_e;
1626                 if (dwarf_func_inline(sp_die))
1627                         param->retval = die_walk_instances(sp_die,
1628                                                 line_range_inline_cb, lf);
1629                 else
1630                         param->retval = find_line_range_by_line(sp_die, lf);
1631                 return DWARF_CB_ABORT;
1632         }
1633         return DWARF_CB_OK;
1634 }
1635
1636 static int find_line_range_by_func(struct line_finder *lf)
1637 {
1638         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1639         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1640         return param.retval;
1641 }
1642
1643 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1644 {
1645         struct line_finder lf = {.lr = lr, .found = 0};
1646         int ret = 0;
1647         Dwarf_Off off = 0, noff;
1648         size_t cuhl;
1649         Dwarf_Die *diep;
1650         const char *comp_dir;
1651
1652         /* Fastpath: lookup by function name from .debug_pubnames section */
1653         if (lr->function) {
1654                 struct pubname_callback_param pubname_param = {
1655                         .function = lr->function, .file = lr->file,
1656                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1657                 struct dwarf_callback_param line_range_param = {
1658                         .data = (void *)&lf, .retval = 0};
1659
1660                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1661                                   &pubname_param, 0);
1662                 if (pubname_param.found) {
1663                         line_range_search_cb(&lf.sp_die, &line_range_param);
1664                         if (lf.found)
1665                                 goto found;
1666                 }
1667         }
1668
1669         /* Loop on CUs (Compilation Unit) */
1670         while (!lf.found && ret >= 0) {
1671                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1672                                  NULL, NULL, NULL) != 0)
1673                         break;
1674
1675                 /* Get the DIE(Debugging Information Entry) of this CU */
1676                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1677                 if (!diep)
1678                         continue;
1679
1680                 /* Check if target file is included. */
1681                 if (lr->file)
1682                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1683                 else
1684                         lf.fname = 0;
1685
1686                 if (!lr->file || lf.fname) {
1687                         if (lr->function)
1688                                 ret = find_line_range_by_func(&lf);
1689                         else {
1690                                 lf.lno_s = lr->start;
1691                                 lf.lno_e = lr->end;
1692                                 ret = find_line_range_by_line(NULL, &lf);
1693                         }
1694                 }
1695                 off = noff;
1696         }
1697
1698 found:
1699         /* Store comp_dir */
1700         if (lf.found) {
1701                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1702                 if (comp_dir) {
1703                         lr->comp_dir = strdup(comp_dir);
1704                         if (!lr->comp_dir)
1705                                 ret = -ENOMEM;
1706                 }
1707         }
1708
1709         pr_debug("path: %s\n", lr->path);
1710         return (ret < 0) ? ret : lf.found;
1711 }
1712