tools/perf/util/probe-finder.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * probe-finder.c : C expression to kprobe event converter
   4  *
   5  * Written by Masami Hiramatsu <mhiramat@redhat.com>
   6  */
   7
   8 #include <inttypes.h>
   9 #include <sys/utsname.h>
  10 #include <sys/types.h>
  11 #include <sys/stat.h>
  12 #include <fcntl.h>
  13 #include <errno.h>
  14 #include <stdio.h>
  15 #include <unistd.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <stdarg.h>
  19 #include <dwarf-regs.h>
  20
  21 #include <linux/bitops.h>
  22 #include <linux/zalloc.h>
  23 #include "event.h"
  24 #include "dso.h"
  25 #include "debug.h"
  26 #include "intlist.h"
  27 #include "strbuf.h"
  28 #include "strlist.h"
  29 #include "symbol.h"
  30 #include "probe-finder.h"
  31 #include "probe-file.h"
  32 #include "string2.h"
  33
  34 /* Kprobe tracer basic type is up to u64 */
  35 #define MAX_BASIC_TYPE_BITS     64
  36
  37 /* Dwarf FL wrappers */
  38 static char *debuginfo_path;    /* Currently dummy */
  39
  40 static const Dwfl_Callbacks offline_callbacks = {
  41         .find_debuginfo = dwfl_standard_find_debuginfo,
  42         .debuginfo_path = &debuginfo_path,
  43
  44         .section_address = dwfl_offline_section_address,
  45
  46         /* We use this table for core files too.  */
  47         .find_elf = dwfl_build_id_find_elf,
  48 };
  49
  50 /* Get a Dwarf from offline image */
  51 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
  52                                          const char *path)
  53 {
  54         int fd;
  55
  56         fd = open(path, O_RDONLY);
  57         if (fd < 0)
  58                 return fd;
  59
  60         dbg->dwfl = dwfl_begin(&offline_callbacks);
  61         if (!dbg->dwfl)
  62                 goto error;
  63
  64         dwfl_report_begin(dbg->dwfl);
  65         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
  66         if (!dbg->mod)
  67                 goto error;
  68
  69         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
  70         if (!dbg->dbg)
  71                 goto error;
  72
  73         dwfl_report_end(dbg->dwfl, NULL, NULL);
  74
  75         return 0;
  76 error:
  77         if (dbg->dwfl)
  78                 dwfl_end(dbg->dwfl);
  79         else
  80                 close(fd);
  81         memset(dbg, 0, sizeof(*dbg));
  82
  83         return -ENOENT;
  84 }
  85
  86 static struct debuginfo *__debuginfo__new(const char *path)
  87 {
  88         struct debuginfo *dbg = zalloc(sizeof(*dbg));
  89         if (!dbg)
  90                 return NULL;
  91
  92         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
  93                 zfree(&dbg);
  94         if (dbg)
  95                 pr_debug("Open Debuginfo file: %s\n", path);
  96         return dbg;
  97 }
  98
  99 enum dso_binary_type distro_dwarf_types[] = {
 100         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
 101         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
 102         DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
 103         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
 104         DSO_BINARY_TYPE__NOT_FOUND,
 105 };
 106
 107 struct debuginfo *debuginfo__new(const char *path)
 108 {
 109         enum dso_binary_type *type;
 110         char buf[PATH_MAX], nil = '\0';
 111         struct dso *dso;
 112         struct debuginfo *dinfo = NULL;
 113
 114         /* Try to open distro debuginfo files */
 115         dso = dso__new(path);
 116         if (!dso)
 117                 goto out;
 118
 119         for (type = distro_dwarf_types;
 120              !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
 121              type++) {
 122                 if (dso__read_binary_type_filename(dso, *type, &nil,
 123                                                    buf, PATH_MAX) < 0)
 124                         continue;
 125                 dinfo = __debuginfo__new(buf);
 126         }
 127         dso__put(dso);
 128
 129 out:
 130         /* if failed to open all distro debuginfo, open given binary */
 131         return dinfo ? : __debuginfo__new(path);
 132 }
 133
 134 void debuginfo__delete(struct debuginfo *dbg)
 135 {
 136         if (dbg) {
 137                 if (dbg->dwfl)
 138                         dwfl_end(dbg->dwfl);
 139                 free(dbg);
 140         }
 141 }
 142
 143 /*
 144  * Probe finder related functions
 145  */
 146
 147 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 148 {
 149         struct probe_trace_arg_ref *ref;
 150         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 151         if (ref != NULL)
 152                 ref->offset = offs;
 153         return ref;
 154 }
 155
 156 /*
 157  * Convert a location into trace_arg.
 158  * If tvar == NULL, this just checks variable can be converted.
 159  * If fentry == true and vr_die is a parameter, do huristic search
 160  * for the location fuzzed by function entry mcount.
 161  */
 162 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 163                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
 164                                      unsigned int machine,
 165                                      struct probe_trace_arg *tvar)
 166 {
 167         Dwarf_Attribute attr;
 168         Dwarf_Addr tmp = 0;
 169         Dwarf_Op *op;
 170         size_t nops;
 171         unsigned int regn;
 172         Dwarf_Word offs = 0;
 173         bool ref = false;
 174         const char *regs;
 175         int ret, ret2 = 0;
 176
 177         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 178                 goto static_var;
 179
 180         /* TODO: handle more than 1 exprs */
 181         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 182                 return -EINVAL; /* Broken DIE ? */
 183         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 184                 ret = dwarf_entrypc(sp_die, &tmp);
 185                 if (ret)
 186                         return -ENOENT;
 187
 188                 if (probe_conf.show_location_range &&
 189                         (dwarf_tag(vr_die) == DW_TAG_variable)) {
 190                         ret2 = -ERANGE;
 191                 } else if (addr != tmp ||
 192                         dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
 193                         return -ENOENT;
 194                 }
 195
 196                 ret = dwarf_highpc(sp_die, &tmp);
 197                 if (ret)
 198                         return -ENOENT;
 199                 /*
 200                  * This is fuzzed by fentry mcount. We try to find the
 201                  * parameter location at the earliest address.
 202                  */
 203                 for (addr += 1; addr <= tmp; addr++) {
 204                         if (dwarf_getlocation_addr(&attr, addr, &op,
 205                                                    &nops, 1) > 0)
 206                                 goto found;
 207                 }
 208                 return -ENOENT;
 209         }
 210 found:
 211         if (nops == 0)
 212                 /* TODO: Support const_value */
 213                 return -ENOENT;
 214
 215         if (op->atom == DW_OP_addr) {
 216 static_var:
 217                 if (!tvar)
 218                         return ret2;
 219                 /* Static variables on memory (not stack), make @varname */
 220                 ret = strlen(dwarf_diename(vr_die));
 221                 tvar->value = zalloc(ret + 2);
 222                 if (tvar->value == NULL)
 223                         return -ENOMEM;
 224                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 225                 tvar->ref = alloc_trace_arg_ref((long)offs);
 226                 if (tvar->ref == NULL)
 227                         return -ENOMEM;
 228                 return ret2;
 229         }
 230
 231         /* If this is based on frame buffer, set the offset */
 232         if (op->atom == DW_OP_fbreg) {
 233                 if (fb_ops == NULL)
 234                         return -ENOTSUP;
 235                 ref = true;
 236                 offs = op->number;
 237                 op = &fb_ops[0];
 238         }
 239
 240         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 241                 regn = op->atom - DW_OP_breg0;
 242                 offs += op->number;
 243                 ref = true;
 244         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 245                 regn = op->atom - DW_OP_reg0;
 246         } else if (op->atom == DW_OP_bregx) {
 247                 regn = op->number;
 248                 offs += op->number2;
 249                 ref = true;
 250         } else if (op->atom == DW_OP_regx) {
 251                 regn = op->number;
 252         } else {
 253                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 254                 return -ENOTSUP;
 255         }
 256
 257         if (!tvar)
 258                 return ret2;
 259
 260         regs = get_dwarf_regstr(regn, machine);
 261         if (!regs) {
 262                 /* This should be a bug in DWARF or this tool */
 263                 pr_warning("Mapping for the register number %u "
 264                            "missing on this architecture.\n", regn);
 265                 return -ENOTSUP;
 266         }
 267
 268         tvar->value = strdup(regs);
 269         if (tvar->value == NULL)
 270                 return -ENOMEM;
 271
 272         if (ref) {
 273                 tvar->ref = alloc_trace_arg_ref((long)offs);
 274                 if (tvar->ref == NULL)
 275                         return -ENOMEM;
 276         }
 277         return ret2;
 278 }
 279
 280 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 281
 282 static int convert_variable_type(Dwarf_Die *vr_die,
 283                                  struct probe_trace_arg *tvar,
 284                                  const char *cast, bool user_access)
 285 {
 286         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 287         Dwarf_Die type;
 288         char buf[16];
 289         char sbuf[STRERR_BUFSIZE];
 290         int bsize, boffs, total;
 291         int ret;
 292         char prefix;
 293
 294         /* TODO: check all types */
 295         if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
 296             strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
 297                 /* Non string type is OK */
 298                 /* and respect signedness/hexadecimal cast */
 299                 tvar->type = strdup(cast);
 300                 return (tvar->type == NULL) ? -ENOMEM : 0;
 301         }
 302
 303         bsize = dwarf_bitsize(vr_die);
 304         if (bsize > 0) {
 305                 /* This is a bitfield */
 306                 boffs = dwarf_bitoffset(vr_die);
 307                 total = dwarf_bytesize(vr_die);
 308                 if (boffs < 0 || total < 0)
 309                         return -ENOENT;
 310                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 311                                 BYTES_TO_BITS(total));
 312                 goto formatted;
 313         }
 314
 315         if (die_get_real_type(vr_die, &type) == NULL) {
 316                 pr_warning("Failed to get a type information of %s.\n",
 317                            dwarf_diename(vr_die));
 318                 return -ENOENT;
 319         }
 320
 321         pr_debug("%s type is %s.\n",
 322                  dwarf_diename(vr_die), dwarf_diename(&type));
 323
 324         if (cast && (!strcmp(cast, "string") || !strcmp(cast, "ustring"))) {
 325                 /* String type */
 326                 ret = dwarf_tag(&type);
 327                 if (ret != DW_TAG_pointer_type &&
 328                     ret != DW_TAG_array_type) {
 329                         pr_warning("Failed to cast into string: "
 330                                    "%s(%s) is not a pointer nor array.\n",
 331                                    dwarf_diename(vr_die), dwarf_diename(&type));
 332                         return -EINVAL;
 333                 }
 334                 if (die_get_real_type(&type, &type) == NULL) {
 335                         pr_warning("Failed to get a type"
 336                                    " information.\n");
 337                         return -ENOENT;
 338                 }
 339                 if (ret == DW_TAG_pointer_type) {
 340                         while (*ref_ptr)
 341                                 ref_ptr = &(*ref_ptr)->next;
 342                         /* Add new reference with offset +0 */
 343                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 344                         if (*ref_ptr == NULL) {
 345                                 pr_warning("Out of memory error\n");
 346                                 return -ENOMEM;
 347                         }
 348                         (*ref_ptr)->user_access = user_access;
 349                 }
 350                 if (!die_compare_name(&type, "char") &&
 351                     !die_compare_name(&type, "unsigned char")) {
 352                         pr_warning("Failed to cast into string: "
 353                                    "%s is not (unsigned) char *.\n",
 354                                    dwarf_diename(vr_die));
 355                         return -EINVAL;
 356                 }
 357                 tvar->type = strdup(cast);
 358                 return (tvar->type == NULL) ? -ENOMEM : 0;
 359         }
 360
 361         if (cast && (strcmp(cast, "u") == 0))
 362                 prefix = 'u';
 363         else if (cast && (strcmp(cast, "s") == 0))
 364                 prefix = 's';
 365         else if (cast && (strcmp(cast, "x") == 0) &&
 366                  probe_type_is_available(PROBE_TYPE_X))
 367                 prefix = 'x';
 368         else
 369                 prefix = die_is_signed_type(&type) ? 's' :
 370                          probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
 371
 372         ret = dwarf_bytesize(&type);
 373         if (ret <= 0)
 374                 /* No size ... try to use default type */
 375                 return 0;
 376         ret = BYTES_TO_BITS(ret);
 377
 378         /* Check the bitwidth */
 379         if (ret > MAX_BASIC_TYPE_BITS) {
 380                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 381                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 382                 ret = MAX_BASIC_TYPE_BITS;
 383         }
 384         ret = snprintf(buf, 16, "%c%d", prefix, ret);
 385
 386 formatted:
 387         if (ret < 0 || ret >= 16) {
 388                 if (ret >= 16)
 389                         ret = -E2BIG;
 390                 pr_warning("Failed to convert variable type: %s\n",
 391                            str_error_r(-ret, sbuf, sizeof(sbuf)));
 392                 return ret;
 393         }
 394         tvar->type = strdup(buf);
 395         if (tvar->type == NULL)
 396                 return -ENOMEM;
 397         return 0;
 398 }
 399
 400 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 401                                     struct perf_probe_arg_field *field,
 402                                     struct probe_trace_arg_ref **ref_ptr,
 403                                     Dwarf_Die *die_mem, bool user_access)
 404 {
 405         struct probe_trace_arg_ref *ref = *ref_ptr;
 406         Dwarf_Die type;
 407         Dwarf_Word offs;
 408         int ret, tag;
 409
 410         pr_debug("converting %s in %s\n", field->name, varname);
 411         if (die_get_real_type(vr_die, &type) == NULL) {
 412                 pr_warning("Failed to get the type of %s.\n", varname);
 413                 return -ENOENT;
 414         }
 415         pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type),
 416                   (unsigned)dwarf_dieoffset(&type));
 417         tag = dwarf_tag(&type);
 418
 419         if (field->name[0] == '[' &&
 420             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 421                 /* Save original type for next field or type */
 422                 memcpy(die_mem, &type, sizeof(*die_mem));
 423                 /* Get the type of this array */
 424                 if (die_get_real_type(&type, &type) == NULL) {
 425                         pr_warning("Failed to get the type of %s.\n", varname);
 426                         return -ENOENT;
 427                 }
 428                 pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type),
 429                          (unsigned)dwarf_dieoffset(&type));
 430                 if (tag == DW_TAG_pointer_type) {
 431                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 432                         if (ref == NULL)
 433                                 return -ENOMEM;
 434                         if (*ref_ptr)
 435                                 (*ref_ptr)->next = ref;
 436                         else
 437                                 *ref_ptr = ref;
 438                 }
 439                 ref->offset += dwarf_bytesize(&type) * field->index;
 440                 ref->user_access = user_access;
 441                 goto next;
 442         } else if (tag == DW_TAG_pointer_type) {
 443                 /* Check the pointer and dereference */
 444                 if (!field->ref) {
 445                         pr_err("Semantic error: %s must be referred by '->'\n",
 446                                field->name);
 447                         return -EINVAL;
 448                 }
 449                 /* Get the type pointed by this pointer */
 450                 if (die_get_real_type(&type, &type) == NULL) {
 451                         pr_warning("Failed to get the type of %s.\n", varname);
 452                         return -ENOENT;
 453                 }
 454                 /* Verify it is a data structure  */
 455                 tag = dwarf_tag(&type);
 456                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 457                         pr_warning("%s is not a data structure nor a union.\n",
 458                                    varname);
 459                         return -EINVAL;
 460                 }
 461
 462                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 463                 if (ref == NULL)
 464                         return -ENOMEM;
 465                 if (*ref_ptr)
 466                         (*ref_ptr)->next = ref;
 467                 else
 468                         *ref_ptr = ref;
 469         } else {
 470                 /* Verify it is a data structure  */
 471                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 472                         pr_warning("%s is not a data structure nor a union.\n",
 473                                    varname);
 474                         return -EINVAL;
 475                 }
 476                 if (field->name[0] == '[') {
 477                         pr_err("Semantic error: %s is not a pointer"
 478                                " nor array.\n", varname);
 479                         return -EINVAL;
 480                 }
 481                 /* While prcessing unnamed field, we don't care about this */
 482                 if (field->ref && dwarf_diename(vr_die)) {
 483                         pr_err("Semantic error: %s must be referred by '.'\n",
 484                                field->name);
 485                         return -EINVAL;
 486                 }
 487                 if (!ref) {
 488                         pr_warning("Structure on a register is not "
 489                                    "supported yet.\n");
 490                         return -ENOTSUP;
 491                 }
 492         }
 493
 494         if (die_find_member(&type, field->name, die_mem) == NULL) {
 495                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 496                            dwarf_diename(&type), field->name);
 497                 return -EINVAL;
 498         }
 499
 500         /* Get the offset of the field */
 501         if (tag == DW_TAG_union_type) {
 502                 offs = 0;
 503         } else {
 504                 ret = die_get_data_member_location(die_mem, &offs);
 505                 if (ret < 0) {
 506                         pr_warning("Failed to get the offset of %s.\n",
 507                                    field->name);
 508                         return ret;
 509                 }
 510         }
 511         ref->offset += (long)offs;
 512         ref->user_access = user_access;
 513
 514         /* If this member is unnamed, we need to reuse this field */
 515         if (!dwarf_diename(die_mem))
 516                 return convert_variable_fields(die_mem, varname, field,
 517                                                 &ref, die_mem, user_access);
 518
 519 next:
 520         /* Converting next field */
 521         if (field->next)
 522                 return convert_variable_fields(die_mem, field->name,
 523                                 field->next, &ref, die_mem, user_access);
 524         else
 525                 return 0;
 526 }
 527
 528 /* Show a variables in kprobe event format */
 529 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 530 {
 531         Dwarf_Die die_mem;
 532         int ret;
 533
 534         pr_debug("Converting variable %s into trace event.\n",
 535                  dwarf_diename(vr_die));
 536
 537         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 538                                         &pf->sp_die, pf->machine, pf->tvar);
 539         if (ret == -ENOENT || ret == -EINVAL) {
 540                 pr_err("Failed to find the location of the '%s' variable at this address.\n"
 541                        " Perhaps it has been optimized out.\n"
 542                        " Use -V with the --range option to show '%s' location range.\n",
 543                        pf->pvar->var, pf->pvar->var);
 544         } else if (ret == -ENOTSUP)
 545                 pr_err("Sorry, we don't support this variable location yet.\n");
 546         else if (ret == 0 && pf->pvar->field) {
 547                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 548                                               pf->pvar->field, &pf->tvar->ref,
 549                                               &die_mem, pf->pvar->user_access);
 550                 vr_die = &die_mem;
 551         }
 552         if (ret == 0)
 553                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type,
 554                                             pf->pvar->user_access);
 555         /* *expr will be cached in libdw. Don't free it. */
 556         return ret;
 557 }
 558
 559 /* Find a variable in a scope DIE */
 560 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 561 {
 562         Dwarf_Die vr_die;
 563         char *buf, *ptr;
 564         int ret = 0;
 565
 566         /* Copy raw parameters */
 567         if (!is_c_varname(pf->pvar->var))
 568                 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
 569
 570         if (pf->pvar->name)
 571                 pf->tvar->name = strdup(pf->pvar->name);
 572         else {
 573                 buf = synthesize_perf_probe_arg(pf->pvar);
 574                 if (!buf)
 575                         return -ENOMEM;
 576                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 577                 if (ptr)
 578                         *ptr = '_';
 579                 pf->tvar->name = buf;
 580         }
 581         if (pf->tvar->name == NULL)
 582                 return -ENOMEM;
 583
 584         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 585         /* Search child die for local variables and parameters. */
 586         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 587                 /* Search again in global variables */
 588                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
 589                                                 0, &vr_die)) {
 590                         pr_warning("Failed to find '%s' in this function.\n",
 591                                    pf->pvar->var);
 592                         ret = -ENOENT;
 593                 }
 594         }
 595         if (ret >= 0)
 596                 ret = convert_variable(&vr_die, pf);
 597
 598         return ret;
 599 }
 600
 601 /* Convert subprogram DIE to trace point */
 602 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 603                                   Dwarf_Addr paddr, bool retprobe,
 604                                   const char *function,
 605                                   struct probe_trace_point *tp)
 606 {
 607         Dwarf_Addr eaddr, highaddr;
 608         GElf_Sym sym;
 609         const char *symbol;
 610
 611         /* Verify the address is correct */
 612         if (dwarf_entrypc(sp_die, &eaddr) != 0) {
 613                 pr_warning("Failed to get entry address of %s\n",
 614                            dwarf_diename(sp_die));
 615                 return -ENOENT;
 616         }
 617         if (dwarf_highpc(sp_die, &highaddr) != 0) {
 618                 pr_warning("Failed to get end address of %s\n",
 619                            dwarf_diename(sp_die));
 620                 return -ENOENT;
 621         }
 622         if (paddr > highaddr) {
 623                 pr_warning("Offset specified is greater than size of %s\n",
 624                            dwarf_diename(sp_die));
 625                 return -EINVAL;
 626         }
 627
 628         symbol = dwarf_diename(sp_die);
 629         if (!symbol) {
 630                 /* Try to get the symbol name from symtab */
 631                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 632                 if (!symbol) {
 633                         pr_warning("Failed to find symbol at 0x%lx\n",
 634                                    (unsigned long)paddr);
 635                         return -ENOENT;
 636                 }
 637                 eaddr = sym.st_value;
 638         }
 639         tp->offset = (unsigned long)(paddr - eaddr);
 640         tp->address = (unsigned long)paddr;
 641         tp->symbol = strdup(symbol);
 642         if (!tp->symbol)
 643                 return -ENOMEM;
 644
 645         /* Return probe must be on the head of a subprogram */
 646         if (retprobe) {
 647                 if (eaddr != paddr) {
 648                         pr_warning("Failed to find \"%s%%return\",\n"
 649                                    " because %s is an inlined function and"
 650                                    " has no return point.\n", function,
 651                                    function);
 652                         return -EINVAL;
 653                 }
 654                 tp->retprobe = true;
 655         }
 656
 657         return 0;
 658 }
 659
 660 /* Call probe_finder callback with scope DIE */
 661 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 662 {
 663         Dwarf_Attribute fb_attr;
 664         Dwarf_Frame *frame = NULL;
 665         size_t nops;
 666         int ret;
 667
 668         if (!sc_die) {
 669                 pr_err("Caller must pass a scope DIE. Program error.\n");
 670                 return -EINVAL;
 671         }
 672
 673         /* If not a real subprogram, find a real one */
 674         if (!die_is_func_def(sc_die)) {
 675                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 676                         if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 677                                 pr_warning("Ignoring tail call from %s\n",
 678                                                 dwarf_diename(&pf->sp_die));
 679                                 return 0;
 680                         } else {
 681                                 pr_warning("Failed to find probe point in any "
 682                                            "functions.\n");
 683                                 return -ENOENT;
 684                         }
 685                 }
 686         } else
 687                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 688
 689         /* Get the frame base attribute/ops from subprogram */
 690         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 691         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 692         if (ret <= 0 || nops == 0) {
 693                 pf->fb_ops = NULL;
 694 #if _ELFUTILS_PREREQ(0, 142)
 695         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 696                    (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
 697                 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
 698                      (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
 699                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 700                         pr_warning("Failed to get call frame on 0x%jx\n",
 701                                    (uintmax_t)pf->addr);
 702                         free(frame);
 703                         return -ENOENT;
 704                 }
 705 #endif
 706         }
 707
 708         /* Call finder's callback handler */
 709         ret = pf->callback(sc_die, pf);
 710
 711         /* Since *pf->fb_ops can be a part of frame. we should free it here. */
 712         free(frame);
 713         pf->fb_ops = NULL;
 714
 715         return ret;
 716 }
 717
 718 struct find_scope_param {
 719         const char *function;
 720         const char *file;
 721         int line;
 722         int diff;
 723         Dwarf_Die *die_mem;
 724         bool found;
 725 };
 726
 727 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 728 {
 729         struct find_scope_param *fsp = data;
 730         const char *file;
 731         int lno;
 732
 733         /* Skip if declared file name does not match */
 734         if (fsp->file) {
 735                 file = dwarf_decl_file(fn_die);
 736                 if (!file || strcmp(fsp->file, file) != 0)
 737                         return 0;
 738         }
 739         /* If the function name is given, that's what user expects */
 740         if (fsp->function) {
 741                 if (die_match_name(fn_die, fsp->function)) {
 742                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 743                         fsp->found = true;
 744                         return 1;
 745                 }
 746         } else {
 747                 /* With the line number, find the nearest declared DIE */
 748                 dwarf_decl_line(fn_die, &lno);
 749                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 750                         /* Keep a candidate and continue */
 751                         fsp->diff = fsp->line - lno;
 752                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 753                         fsp->found = true;
 754                 }
 755         }
 756         return 0;
 757 }
 758
 759 /* Return innermost DIE */
 760 static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data)
 761 {
 762         struct find_scope_param *fsp = data;
 763
 764         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 765         fsp->found = true;
 766         return 1;
 767 }
 768
 769 /* Find an appropriate scope fits to given conditions */
 770 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 771 {
 772         struct find_scope_param fsp = {
 773                 .function = pf->pev->point.function,
 774                 .file = pf->fname,
 775                 .line = pf->lno,
 776                 .diff = INT_MAX,
 777                 .die_mem = die_mem,
 778                 .found = false,
 779         };
 780         int ret;
 781
 782         ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb,
 783                                    &fsp);
 784         if (!ret && !fsp.found)
 785                 cu_walk_functions_at(&pf->cu_die, pf->addr,
 786                                      find_inner_scope_cb, &fsp);
 787
 788         return fsp.found ? die_mem : NULL;
 789 }
 790
 791 static int probe_point_line_walker(const char *fname, int lineno,
 792                                    Dwarf_Addr addr, void *data)
 793 {
 794         struct probe_finder *pf = data;
 795         Dwarf_Die *sc_die, die_mem;
 796         int ret;
 797
 798         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 799                 return 0;
 800
 801         pf->addr = addr;
 802         sc_die = find_best_scope(pf, &die_mem);
 803         if (!sc_die) {
 804                 pr_warning("Failed to find scope of probe point.\n");
 805                 return -ENOENT;
 806         }
 807
 808         ret = call_probe_finder(sc_die, pf);
 809
 810         /* Continue if no error, because the line will be in inline function */
 811         return ret < 0 ? ret : 0;
 812 }
 813
 814 /* Find probe point from its line number */
 815 static int find_probe_point_by_line(struct probe_finder *pf)
 816 {
 817         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 818 }
 819
 820 /* Find lines which match lazy pattern */
 821 static int find_lazy_match_lines(struct intlist *list,
 822                                  const char *fname, const char *pat)
 823 {
 824         FILE *fp;
 825         char *line = NULL;
 826         size_t line_len;
 827         ssize_t len;
 828         int count = 0, linenum = 1;
 829         char sbuf[STRERR_BUFSIZE];
 830
 831         fp = fopen(fname, "r");
 832         if (!fp) {
 833                 pr_warning("Failed to open %s: %s\n", fname,
 834                            str_error_r(errno, sbuf, sizeof(sbuf)));
 835                 return -errno;
 836         }
 837
 838         while ((len = getline(&line, &line_len, fp)) > 0) {
 839
 840                 if (line[len - 1] == '\n')
 841                         line[len - 1] = '\0';
 842
 843                 if (strlazymatch(line, pat)) {
 844                         intlist__add(list, linenum);
 845                         count++;
 846                 }
 847                 linenum++;
 848         }
 849
 850         if (ferror(fp))
 851                 count = -errno;
 852         free(line);
 853         fclose(fp);
 854
 855         if (count == 0)
 856                 pr_debug("No matched lines found in %s.\n", fname);
 857         return count;
 858 }
 859
 860 static int probe_point_lazy_walker(const char *fname, int lineno,
 861                                    Dwarf_Addr addr, void *data)
 862 {
 863         struct probe_finder *pf = data;
 864         Dwarf_Die *sc_die, die_mem;
 865         int ret;
 866
 867         if (!intlist__has_entry(pf->lcache, lineno) ||
 868             strtailcmp(fname, pf->fname) != 0)
 869                 return 0;
 870
 871         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 872                  lineno, (unsigned long long)addr);
 873         pf->addr = addr;
 874         pf->lno = lineno;
 875         sc_die = find_best_scope(pf, &die_mem);
 876         if (!sc_die) {
 877                 pr_warning("Failed to find scope of probe point.\n");
 878                 return -ENOENT;
 879         }
 880
 881         ret = call_probe_finder(sc_die, pf);
 882
 883         /*
 884          * Continue if no error, because the lazy pattern will match
 885          * to other lines
 886          */
 887         return ret < 0 ? ret : 0;
 888 }
 889
 890 /* Find probe points from lazy pattern  */
 891 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 892 {
 893         int ret = 0;
 894         char *fpath;
 895
 896         if (intlist__empty(pf->lcache)) {
 897                 const char *comp_dir;
 898
 899                 comp_dir = cu_get_comp_dir(&pf->cu_die);
 900                 ret = get_real_path(pf->fname, comp_dir, &fpath);
 901                 if (ret < 0) {
 902                         pr_warning("Failed to find source file path.\n");
 903                         return ret;
 904                 }
 905
 906                 /* Matching lazy line pattern */
 907                 ret = find_lazy_match_lines(pf->lcache, fpath,
 908                                             pf->pev->point.lazy_line);
 909                 free(fpath);
 910                 if (ret <= 0)
 911                         return ret;
 912         }
 913
 914         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 915 }
 916
 917 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
 918 {
 919         struct perf_probe_point *pp = &pf->pev->point;
 920
 921         /* Not uprobe? */
 922         if (!pf->pev->uprobes)
 923                 return;
 924
 925         /* Compiled with optimization? */
 926         if (die_is_optimized_target(&pf->cu_die))
 927                 return;
 928
 929         /* Don't know entrypc? */
 930         if (!pf->addr)
 931                 return;
 932
 933         /* Only FUNC and FUNC@SRC are eligible. */
 934         if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
 935             pp->offset || pp->abs_address)
 936                 return;
 937
 938         /* Not interested in func parameter? */
 939         if (!perf_probe_with_var(pf->pev))
 940                 return;
 941
 942         pr_info("Target program is compiled without optimization. Skipping prologue.\n"
 943                 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
 944                 pf->addr);
 945
 946         die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
 947 }
 948
 949 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 950 {
 951         struct probe_finder *pf = data;
 952         struct perf_probe_point *pp = &pf->pev->point;
 953         Dwarf_Addr addr;
 954         int ret;
 955
 956         if (pp->lazy_line)
 957                 ret = find_probe_point_lazy(in_die, pf);
 958         else {
 959                 /* Get probe address */
 960                 if (die_entrypc(in_die, &addr) != 0) {
 961                         pr_warning("Failed to get entry address of %s.\n",
 962                                    dwarf_diename(in_die));
 963                         return -ENOENT;
 964                 }
 965                 if (addr == 0) {
 966                         pr_debug("%s has no valid entry address. skipped.\n",
 967                                  dwarf_diename(in_die));
 968                         return -ENOENT;
 969                 }
 970                 pf->addr = addr;
 971                 pf->addr += pp->offset;
 972                 pr_debug("found inline addr: 0x%jx\n",
 973                          (uintmax_t)pf->addr);
 974
 975                 ret = call_probe_finder(in_die, pf);
 976         }
 977
 978         return ret;
 979 }
 980
 981 /* Callback parameter with return value for libdw */
 982 struct dwarf_callback_param {
 983         void *data;
 984         int retval;
 985 };
 986
 987 /* Search function from function name */
 988 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 989 {
 990         struct dwarf_callback_param *param = data;
 991         struct probe_finder *pf = param->data;
 992         struct perf_probe_point *pp = &pf->pev->point;
 993
 994         /* Check tag and diename */
 995         if (!die_is_func_def(sp_die) ||
 996             !die_match_name(sp_die, pp->function))
 997                 return DWARF_CB_OK;
 998
 999         /* Check declared file */
1000         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
1001                 return DWARF_CB_OK;
1002
1003         pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
1004                  (unsigned long)dwarf_dieoffset(sp_die));
1005         pf->fname = dwarf_decl_file(sp_die);
1006         if (pp->line) { /* Function relative line */
1007                 dwarf_decl_line(sp_die, &pf->lno);
1008                 pf->lno += pp->line;
1009                 param->retval = find_probe_point_by_line(pf);
1010         } else if (die_is_func_instance(sp_die)) {
1011                 /* Instances always have the entry address */
1012                 die_entrypc(sp_die, &pf->addr);
1013                 /* But in some case the entry address is 0 */
1014                 if (pf->addr == 0) {
1015                         pr_debug("%s has no entry PC. Skipped\n",
1016                                  dwarf_diename(sp_die));
1017                         param->retval = 0;
1018                 /* Real function */
1019                 } else if (pp->lazy_line)
1020                         param->retval = find_probe_point_lazy(sp_die, pf);
1021                 else {
1022                         skip_prologue(sp_die, pf);
1023                         pf->addr += pp->offset;
1024                         /* TODO: Check the address in this function */
1025                         param->retval = call_probe_finder(sp_die, pf);
1026                 }
1027         } else if (!probe_conf.no_inlines) {
1028                 /* Inlined function: search instances */
1029                 param->retval = die_walk_instances(sp_die,
1030                                         probe_point_inline_cb, (void *)pf);
1031                 /* This could be a non-existed inline definition */
1032                 if (param->retval == -ENOENT)
1033                         param->retval = 0;
1034         }
1035
1036         /* We need to find other candidates */
1037         if (strisglob(pp->function) && param->retval >= 0) {
1038                 param->retval = 0;      /* We have to clear the result */
1039                 return DWARF_CB_OK;
1040         }
1041
1042         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1043 }
1044
1045 static int find_probe_point_by_func(struct probe_finder *pf)
1046 {
1047         struct dwarf_callback_param _param = {.data = (void *)pf,
1048                                               .retval = 0};
1049         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1050         return _param.retval;
1051 }
1052
1053 struct pubname_callback_param {
1054         char *function;
1055         char *file;
1056         Dwarf_Die *cu_die;
1057         Dwarf_Die *sp_die;
1058         int found;
1059 };
1060
1061 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1062 {
1063         struct pubname_callback_param *param = data;
1064
1065         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1066                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1067                         return DWARF_CB_OK;
1068
1069                 if (die_match_name(param->sp_die, param->function)) {
1070                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1071                                 return DWARF_CB_OK;
1072
1073                         if (param->file &&
1074                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1075                                 return DWARF_CB_OK;
1076
1077                         param->found = 1;
1078                         return DWARF_CB_ABORT;
1079                 }
1080         }
1081
1082         return DWARF_CB_OK;
1083 }
1084
1085 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1086                                   struct probe_finder *pf)
1087 {
1088         struct perf_probe_point *pp = &pf->pev->point;
1089         Dwarf_Off off, noff;
1090         size_t cuhl;
1091         Dwarf_Die *diep;
1092         int ret = 0;
1093
1094         off = 0;
1095         pf->lcache = intlist__new(NULL);
1096         if (!pf->lcache)
1097                 return -ENOMEM;
1098
1099         /* Fastpath: lookup by function name from .debug_pubnames section */
1100         if (pp->function && !strisglob(pp->function)) {
1101                 struct pubname_callback_param pubname_param = {
1102                         .function = pp->function,
1103                         .file     = pp->file,
1104                         .cu_die   = &pf->cu_die,
1105                         .sp_die   = &pf->sp_die,
1106                         .found    = 0,
1107                 };
1108                 struct dwarf_callback_param probe_param = {
1109                         .data = pf,
1110                 };
1111
1112                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1113                                   &pubname_param, 0);
1114                 if (pubname_param.found) {
1115                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1116                         if (ret)
1117                                 goto found;
1118                 }
1119         }
1120
1121         /* Loop on CUs (Compilation Unit) */
1122         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1123                 /* Get the DIE(Debugging Information Entry) of this CU */
1124                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1125                 if (!diep)
1126                         continue;
1127
1128                 /* Check if target file is included. */
1129                 if (pp->file)
1130                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1131                 else
1132                         pf->fname = NULL;
1133
1134                 if (!pp->file || pf->fname) {
1135                         if (pp->function)
1136                                 ret = find_probe_point_by_func(pf);
1137                         else if (pp->lazy_line)
1138                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1139                         else {
1140                                 pf->lno = pp->line;
1141                                 ret = find_probe_point_by_line(pf);
1142                         }
1143                         if (ret < 0)
1144                                 break;
1145                 }
1146                 off = noff;
1147         }
1148
1149 found:
1150         intlist__delete(pf->lcache);
1151         pf->lcache = NULL;
1152
1153         return ret;
1154 }
1155
1156 /* Find probe points from debuginfo */
1157 static int debuginfo__find_probes(struct debuginfo *dbg,
1158                                   struct probe_finder *pf)
1159 {
1160         int ret = 0;
1161         Elf *elf;
1162         GElf_Ehdr ehdr;
1163
1164         if (pf->cfi_eh || pf->cfi_dbg)
1165                 return debuginfo__find_probe_location(dbg, pf);
1166
1167         /* Get the call frame information from this dwarf */
1168         elf = dwarf_getelf(dbg->dbg);
1169         if (elf == NULL)
1170                 return -EINVAL;
1171
1172         if (gelf_getehdr(elf, &ehdr) == NULL)
1173                 return -EINVAL;
1174
1175         pf->machine = ehdr.e_machine;
1176
1177 #if _ELFUTILS_PREREQ(0, 142)
1178         do {
1179                 GElf_Shdr shdr;
1180
1181                 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1182                     shdr.sh_type == SHT_PROGBITS)
1183                         pf->cfi_eh = dwarf_getcfi_elf(elf);
1184
1185                 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1186         } while (0);
1187 #endif
1188
1189         ret = debuginfo__find_probe_location(dbg, pf);
1190         return ret;
1191 }
1192
1193 struct local_vars_finder {
1194         struct probe_finder *pf;
1195         struct perf_probe_arg *args;
1196         bool vars;
1197         int max_args;
1198         int nargs;
1199         int ret;
1200 };
1201
1202 /* Collect available variables in this scope */
1203 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1204 {
1205         struct local_vars_finder *vf = data;
1206         struct probe_finder *pf = vf->pf;
1207         int tag;
1208
1209         tag = dwarf_tag(die_mem);
1210         if (tag == DW_TAG_formal_parameter ||
1211             (tag == DW_TAG_variable && vf->vars)) {
1212                 if (convert_variable_location(die_mem, vf->pf->addr,
1213                                               vf->pf->fb_ops, &pf->sp_die,
1214                                               pf->machine, NULL) == 0) {
1215                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1216                         if (vf->args[vf->nargs].var == NULL) {
1217                                 vf->ret = -ENOMEM;
1218                                 return DIE_FIND_CB_END;
1219                         }
1220                         pr_debug(" %s", vf->args[vf->nargs].var);
1221                         vf->nargs++;
1222                 }
1223         }
1224
1225         if (dwarf_haspc(die_mem, vf->pf->addr))
1226                 return DIE_FIND_CB_CONTINUE;
1227         else
1228                 return DIE_FIND_CB_SIBLING;
1229 }
1230
1231 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1232                              struct perf_probe_arg *args)
1233 {
1234         Dwarf_Die die_mem;
1235         int i;
1236         int n = 0;
1237         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1238                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1239
1240         for (i = 0; i < pf->pev->nargs; i++) {
1241                 /* var never be NULL */
1242                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1243                         vf.vars = true;
1244                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1245                         /* Copy normal argument */
1246                         args[n] = pf->pev->args[i];
1247                         n++;
1248                         continue;
1249                 }
1250                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1251                 vf.nargs = n;
1252                 /* Special local variables */
1253                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1254                                &die_mem);
1255                 pr_debug(" (%d)\n", vf.nargs - n);
1256                 if (vf.ret < 0)
1257                         return vf.ret;
1258                 n = vf.nargs;
1259         }
1260         return n;
1261 }
1262
1263 static bool trace_event_finder_overlap(struct trace_event_finder *tf)
1264 {
1265         int i;
1266
1267         for (i = 0; i < tf->ntevs; i++) {
1268                 if (tf->pf.addr == tf->tevs[i].point.address)
1269                         return true;
1270         }
1271         return false;
1272 }
1273
1274 /* Add a found probe point into trace event list */
1275 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1276 {
1277         struct trace_event_finder *tf =
1278                         container_of(pf, struct trace_event_finder, pf);
1279         struct perf_probe_point *pp = &pf->pev->point;
1280         struct probe_trace_event *tev;
1281         struct perf_probe_arg *args = NULL;
1282         int ret, i;
1283
1284         /*
1285          * For some reason (e.g. different column assigned to same address)
1286          * This callback can be called with the address which already passed.
1287          * Ignore it first.
1288          */
1289         if (trace_event_finder_overlap(tf))
1290                 return 0;
1291
1292         /* Check number of tevs */
1293         if (tf->ntevs == tf->max_tevs) {
1294                 pr_warning("Too many( > %d) probe point found.\n",
1295                            tf->max_tevs);
1296                 return -ERANGE;
1297         }
1298         tev = &tf->tevs[tf->ntevs++];
1299
1300         /* Trace point should be converted from subprogram DIE */
1301         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1302                                      pp->retprobe, pp->function, &tev->point);
1303         if (ret < 0)
1304                 goto end;
1305
1306         tev->point.realname = strdup(dwarf_diename(sc_die));
1307         if (!tev->point.realname) {
1308                 ret = -ENOMEM;
1309                 goto end;
1310         }
1311
1312         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1313                  tev->point.offset);
1314
1315         /* Expand special probe argument if exist */
1316         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1317         if (args == NULL) {
1318                 ret = -ENOMEM;
1319                 goto end;
1320         }
1321
1322         ret = expand_probe_args(sc_die, pf, args);
1323         if (ret < 0)
1324                 goto end;
1325
1326         tev->nargs = ret;
1327         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1328         if (tev->args == NULL) {
1329                 ret = -ENOMEM;
1330                 goto end;
1331         }
1332
1333         /* Find each argument */
1334         for (i = 0; i < tev->nargs; i++) {
1335                 pf->pvar = &args[i];
1336                 pf->tvar = &tev->args[i];
1337                 /* Variable should be found from scope DIE */
1338                 ret = find_variable(sc_die, pf);
1339                 if (ret != 0)
1340                         break;
1341         }
1342
1343 end:
1344         if (ret) {
1345                 clear_probe_trace_event(tev);
1346                 tf->ntevs--;
1347         }
1348         free(args);
1349         return ret;
1350 }
1351
1352 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1353 int debuginfo__find_trace_events(struct debuginfo *dbg,
1354                                  struct perf_probe_event *pev,
1355                                  struct probe_trace_event **tevs)
1356 {
1357         struct trace_event_finder tf = {
1358                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1359                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1360         int ret, i;
1361
1362         /* Allocate result tevs array */
1363         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1364         if (*tevs == NULL)
1365                 return -ENOMEM;
1366
1367         tf.tevs = *tevs;
1368         tf.ntevs = 0;
1369
1370         ret = debuginfo__find_probes(dbg, &tf.pf);
1371         if (ret < 0) {
1372                 for (i = 0; i < tf.ntevs; i++)
1373                         clear_probe_trace_event(&tf.tevs[i]);
1374                 zfree(tevs);
1375                 return ret;
1376         }
1377
1378         return (ret < 0) ? ret : tf.ntevs;
1379 }
1380
1381 /* Collect available variables in this scope */
1382 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1383 {
1384         struct available_var_finder *af = data;
1385         struct variable_list *vl;
1386         struct strbuf buf = STRBUF_INIT;
1387         int tag, ret;
1388
1389         vl = &af->vls[af->nvls - 1];
1390
1391         tag = dwarf_tag(die_mem);
1392         if (tag == DW_TAG_formal_parameter ||
1393             tag == DW_TAG_variable) {
1394                 ret = convert_variable_location(die_mem, af->pf.addr,
1395                                                 af->pf.fb_ops, &af->pf.sp_die,
1396                                                 af->pf.machine, NULL);
1397                 if (ret == 0 || ret == -ERANGE) {
1398                         int ret2;
1399                         bool externs = !af->child;
1400
1401                         if (strbuf_init(&buf, 64) < 0)
1402                                 goto error;
1403
1404                         if (probe_conf.show_location_range) {
1405                                 if (!externs)
1406                                         ret2 = strbuf_add(&buf,
1407                                                 ret ? "[INV]\t" : "[VAL]\t", 6);
1408                                 else
1409                                         ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1410                                 if (ret2)
1411                                         goto error;
1412                         }
1413
1414                         ret2 = die_get_varname(die_mem, &buf);
1415
1416                         if (!ret2 && probe_conf.show_location_range &&
1417                                 !externs) {
1418                                 if (strbuf_addch(&buf, '\t') < 0)
1419                                         goto error;
1420                                 ret2 = die_get_var_range(&af->pf.sp_die,
1421                                                         die_mem, &buf);
1422                         }
1423
1424                         pr_debug("Add new var: %s\n", buf.buf);
1425                         if (ret2 == 0) {
1426                                 strlist__add(vl->vars,
1427                                         strbuf_detach(&buf, NULL));
1428                         }
1429                         strbuf_release(&buf);
1430                 }
1431         }
1432
1433         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1434                 return DIE_FIND_CB_CONTINUE;
1435         else
1436                 return DIE_FIND_CB_SIBLING;
1437 error:
1438         strbuf_release(&buf);
1439         pr_debug("Error in strbuf\n");
1440         return DIE_FIND_CB_END;
1441 }
1442
1443 static bool available_var_finder_overlap(struct available_var_finder *af)
1444 {
1445         int i;
1446
1447         for (i = 0; i < af->nvls; i++) {
1448                 if (af->pf.addr == af->vls[i].point.address)
1449                         return true;
1450         }
1451         return false;
1452
1453 }
1454
1455 /* Add a found vars into available variables list */
1456 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1457 {
1458         struct available_var_finder *af =
1459                         container_of(pf, struct available_var_finder, pf);
1460         struct perf_probe_point *pp = &pf->pev->point;
1461         struct variable_list *vl;
1462         Dwarf_Die die_mem;
1463         int ret;
1464
1465         /*
1466          * For some reason (e.g. different column assigned to same address),
1467          * this callback can be called with the address which already passed.
1468          * Ignore it first.
1469          */
1470         if (available_var_finder_overlap(af))
1471                 return 0;
1472
1473         /* Check number of tevs */
1474         if (af->nvls == af->max_vls) {
1475                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1476                 return -ERANGE;
1477         }
1478         vl = &af->vls[af->nvls++];
1479
1480         /* Trace point should be converted from subprogram DIE */
1481         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1482                                      pp->retprobe, pp->function, &vl->point);
1483         if (ret < 0)
1484                 return ret;
1485
1486         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1487                  vl->point.offset);
1488
1489         /* Find local variables */
1490         vl->vars = strlist__new(NULL, NULL);
1491         if (vl->vars == NULL)
1492                 return -ENOMEM;
1493         af->child = true;
1494         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1495
1496         /* Find external variables */
1497         if (!probe_conf.show_ext_vars)
1498                 goto out;
1499         /* Don't need to search child DIE for external vars. */
1500         af->child = false;
1501         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1502
1503 out:
1504         if (strlist__empty(vl->vars)) {
1505                 strlist__delete(vl->vars);
1506                 vl->vars = NULL;
1507         }
1508
1509         return ret;
1510 }
1511
1512 /*
1513  * Find available variables at given probe point
1514  * Return the number of found probe points. Return 0 if there is no
1515  * matched probe point. Return <0 if an error occurs.
1516  */
1517 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1518                                       struct perf_probe_event *pev,
1519                                       struct variable_list **vls)
1520 {
1521         struct available_var_finder af = {
1522                         .pf = {.pev = pev, .callback = add_available_vars},
1523                         .mod = dbg->mod,
1524                         .max_vls = probe_conf.max_probes};
1525         int ret;
1526
1527         /* Allocate result vls array */
1528         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1529         if (*vls == NULL)
1530                 return -ENOMEM;
1531
1532         af.vls = *vls;
1533         af.nvls = 0;
1534
1535         ret = debuginfo__find_probes(dbg, &af.pf);
1536         if (ret < 0) {
1537                 /* Free vlist for error */
1538                 while (af.nvls--) {
1539                         zfree(&af.vls[af.nvls].point.symbol);
1540                         strlist__delete(af.vls[af.nvls].vars);
1541                 }
1542                 zfree(vls);
1543                 return ret;
1544         }
1545
1546         return (ret < 0) ? ret : af.nvls;
1547 }
1548
1549 /* For the kernel module, we need a special code to get a DIE */
1550 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1551                                 bool adjust_offset)
1552 {
1553         int n, i;
1554         Elf32_Word shndx;
1555         Elf_Scn *scn;
1556         Elf *elf;
1557         GElf_Shdr mem, *shdr;
1558         const char *p;
1559
1560         elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1561         if (!elf)
1562                 return -EINVAL;
1563
1564         /* Get the number of relocations */
1565         n = dwfl_module_relocations(dbg->mod);
1566         if (n < 0)
1567                 return -ENOENT;
1568         /* Search the relocation related .text section */
1569         for (i = 0; i < n; i++) {
1570                 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1571                 if (strcmp(p, ".text") == 0) {
1572                         /* OK, get the section header */
1573                         scn = elf_getscn(elf, shndx);
1574                         if (!scn)
1575                                 return -ENOENT;
1576                         shdr = gelf_getshdr(scn, &mem);
1577                         if (!shdr)
1578                                 return -ENOENT;
1579                         *offs = shdr->sh_addr;
1580                         if (adjust_offset)
1581                                 *offs -= shdr->sh_offset;
1582                 }
1583         }
1584         return 0;
1585 }
1586
1587 /* Reverse search */
1588 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1589                                 struct perf_probe_point *ppt)
1590 {
1591         Dwarf_Die cudie, spdie, indie;
1592         Dwarf_Addr _addr = 0, baseaddr = 0;
1593         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1594         int baseline = 0, lineno = 0, ret = 0;
1595
1596         /* We always need to relocate the address for aranges */
1597         if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1598                 addr += baseaddr;
1599         /* Find cu die */
1600         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1601                 pr_warning("Failed to find debug information for address %lx\n",
1602                            addr);
1603                 ret = -EINVAL;
1604                 goto end;
1605         }
1606
1607         /* Find a corresponding line (filename and lineno) */
1608         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1609         /* Don't care whether it failed or not */
1610
1611         /* Find a corresponding function (name, baseline and baseaddr) */
1612         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1613                 /* Get function entry information */
1614                 func = basefunc = dwarf_diename(&spdie);
1615                 if (!func ||
1616                     die_entrypc(&spdie, &baseaddr) != 0 ||
1617                     dwarf_decl_line(&spdie, &baseline) != 0) {
1618                         lineno = 0;
1619                         goto post;
1620                 }
1621
1622                 fname = dwarf_decl_file(&spdie);
1623                 if (addr == (unsigned long)baseaddr) {
1624                         /* Function entry - Relative line number is 0 */
1625                         lineno = baseline;
1626                         goto post;
1627                 }
1628
1629                 /* Track down the inline functions step by step */
1630                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1631                                                 &indie)) {
1632                         /* There is an inline function */
1633                         if (die_entrypc(&indie, &_addr) == 0 &&
1634                             _addr == addr) {
1635                                 /*
1636                                  * addr is at an inline function entry.
1637                                  * In this case, lineno should be the call-site
1638                                  * line number. (overwrite lineinfo)
1639                                  */
1640                                 lineno = die_get_call_lineno(&indie);
1641                                 fname = die_get_call_file(&indie);
1642                                 break;
1643                         } else {
1644                                 /*
1645                                  * addr is in an inline function body.
1646                                  * Since lineno points one of the lines
1647                                  * of the inline function, baseline should
1648                                  * be the entry line of the inline function.
1649                                  */
1650                                 tmp = dwarf_diename(&indie);
1651                                 if (!tmp ||
1652                                     dwarf_decl_line(&indie, &baseline) != 0)
1653                                         break;
1654                                 func = tmp;
1655                                 spdie = indie;
1656                         }
1657                 }
1658                 /* Verify the lineno and baseline are in a same file */
1659                 tmp = dwarf_decl_file(&spdie);
1660                 if (!tmp || strcmp(tmp, fname) != 0)
1661                         lineno = 0;
1662         }
1663
1664 post:
1665         /* Make a relative line number or an offset */
1666         if (lineno)
1667                 ppt->line = lineno - baseline;
1668         else if (basefunc) {
1669                 ppt->offset = addr - (unsigned long)baseaddr;
1670                 func = basefunc;
1671         }
1672
1673         /* Duplicate strings */
1674         if (func) {
1675                 ppt->function = strdup(func);
1676                 if (ppt->function == NULL) {
1677                         ret = -ENOMEM;
1678                         goto end;
1679                 }
1680         }
1681         if (fname) {
1682                 ppt->file = strdup(fname);
1683                 if (ppt->file == NULL) {
1684                         zfree(&ppt->function);
1685                         ret = -ENOMEM;
1686                         goto end;
1687                 }
1688         }
1689 end:
1690         if (ret == 0 && (fname || func))
1691                 ret = 1;        /* Found a point */
1692         return ret;
1693 }
1694
1695 /* Add a line and store the src path */
1696 static int line_range_add_line(const char *src, unsigned int lineno,
1697                                struct line_range *lr)
1698 {
1699         /* Copy source path */
1700         if (!lr->path) {
1701                 lr->path = strdup(src);
1702                 if (lr->path == NULL)
1703                         return -ENOMEM;
1704         }
1705         return intlist__add(lr->line_list, lineno);
1706 }
1707
1708 static int line_range_walk_cb(const char *fname, int lineno,
1709                               Dwarf_Addr addr __maybe_unused,
1710                               void *data)
1711 {
1712         struct line_finder *lf = data;
1713         int err;
1714
1715         if ((strtailcmp(fname, lf->fname) != 0) ||
1716             (lf->lno_s > lineno || lf->lno_e < lineno))
1717                 return 0;
1718
1719         err = line_range_add_line(fname, lineno, lf->lr);
1720         if (err < 0 && err != -EEXIST)
1721                 return err;
1722
1723         return 0;
1724 }
1725
1726 /* Find line range from its line number */
1727 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1728 {
1729         int ret;
1730
1731         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1732
1733         /* Update status */
1734         if (ret >= 0)
1735                 if (!intlist__empty(lf->lr->line_list))
1736                         ret = lf->found = 1;
1737                 else
1738                         ret = 0;        /* Lines are not found */
1739         else {
1740                 zfree(&lf->lr->path);
1741         }
1742         return ret;
1743 }
1744
1745 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1746 {
1747         int ret = find_line_range_by_line(in_die, data);
1748
1749         /*
1750          * We have to check all instances of inlined function, because
1751          * some execution paths can be optimized out depends on the
1752          * function argument of instances. However, if an error occurs,
1753          * it should be handled by the caller.
1754          */
1755         return ret < 0 ? ret : 0;
1756 }
1757
1758 /* Search function definition from function name */
1759 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1760 {
1761         struct dwarf_callback_param *param = data;
1762         struct line_finder *lf = param->data;
1763         struct line_range *lr = lf->lr;
1764
1765         /* Check declared file */
1766         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1767                 return DWARF_CB_OK;
1768
1769         if (die_is_func_def(sp_die) &&
1770             die_match_name(sp_die, lr->function)) {
1771                 lf->fname = dwarf_decl_file(sp_die);
1772                 dwarf_decl_line(sp_die, &lr->offset);
1773                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1774                 lf->lno_s = lr->offset + lr->start;
1775                 if (lf->lno_s < 0)      /* Overflow */
1776                         lf->lno_s = INT_MAX;
1777                 lf->lno_e = lr->offset + lr->end;
1778                 if (lf->lno_e < 0)      /* Overflow */
1779                         lf->lno_e = INT_MAX;
1780                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1781                 lr->start = lf->lno_s;
1782                 lr->end = lf->lno_e;
1783                 if (!die_is_func_instance(sp_die))
1784                         param->retval = die_walk_instances(sp_die,
1785                                                 line_range_inline_cb, lf);
1786                 else
1787                         param->retval = find_line_range_by_line(sp_die, lf);
1788                 return DWARF_CB_ABORT;
1789         }
1790         return DWARF_CB_OK;
1791 }
1792
1793 static int find_line_range_by_func(struct line_finder *lf)
1794 {
1795         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1796         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1797         return param.retval;
1798 }
1799
1800 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1801 {
1802         struct line_finder lf = {.lr = lr, .found = 0};
1803         int ret = 0;
1804         Dwarf_Off off = 0, noff;
1805         size_t cuhl;
1806         Dwarf_Die *diep;
1807         const char *comp_dir;
1808
1809         /* Fastpath: lookup by function name from .debug_pubnames section */
1810         if (lr->function) {
1811                 struct pubname_callback_param pubname_param = {
1812                         .function = lr->function, .file = lr->file,
1813                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1814                 struct dwarf_callback_param line_range_param = {
1815                         .data = (void *)&lf, .retval = 0};
1816
1817                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1818                                   &pubname_param, 0);
1819                 if (pubname_param.found) {
1820                         line_range_search_cb(&lf.sp_die, &line_range_param);
1821                         if (lf.found)
1822                                 goto found;
1823                 }
1824         }
1825
1826         /* Loop on CUs (Compilation Unit) */
1827         while (!lf.found && ret >= 0) {
1828                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1829                                  NULL, NULL, NULL) != 0)
1830                         break;
1831
1832                 /* Get the DIE(Debugging Information Entry) of this CU */
1833                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1834                 if (!diep)
1835                         continue;
1836
1837                 /* Check if target file is included. */
1838                 if (lr->file)
1839                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1840                 else
1841                         lf.fname = 0;
1842
1843                 if (!lr->file || lf.fname) {
1844                         if (lr->function)
1845                                 ret = find_line_range_by_func(&lf);
1846                         else {
1847                                 lf.lno_s = lr->start;
1848                                 lf.lno_e = lr->end;
1849                                 ret = find_line_range_by_line(NULL, &lf);
1850                         }
1851                 }
1852                 off = noff;
1853         }
1854
1855 found:
1856         /* Store comp_dir */
1857         if (lf.found) {
1858                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1859                 if (comp_dir) {
1860                         lr->comp_dir = strdup(comp_dir);
1861                         if (!lr->comp_dir)
1862                                 ret = -ENOMEM;
1863                 }
1864         }
1865
1866         pr_debug("path: %s\n", lr->path);
1867         return (ret < 0) ? ret : lf.found;
1868 }
1869
1870 /*
1871  * Find a src file from a DWARF tag path. Prepend optional source path prefix
1872  * and chop off leading directories that do not exist. Result is passed back as
1873  * a newly allocated path on success.
1874  * Return 0 if file was found and readable, -errno otherwise.
1875  */
1876 int get_real_path(const char *raw_path, const char *comp_dir,
1877                          char **new_path)
1878 {
1879         const char *prefix = symbol_conf.source_prefix;
1880
1881         if (!prefix) {
1882                 if (raw_path[0] != '/' && comp_dir)
1883                         /* If not an absolute path, try to use comp_dir */
1884                         prefix = comp_dir;
1885                 else {
1886                         if (access(raw_path, R_OK) == 0) {
1887                                 *new_path = strdup(raw_path);
1888                                 return *new_path ? 0 : -ENOMEM;
1889                         } else
1890                                 return -errno;
1891                 }
1892         }
1893
1894         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1895         if (!*new_path)
1896                 return -ENOMEM;
1897
1898         for (;;) {
1899                 sprintf(*new_path, "%s/%s", prefix, raw_path);
1900
1901                 if (access(*new_path, R_OK) == 0)
1902                         return 0;
1903
1904                 if (!symbol_conf.source_prefix) {
1905                         /* In case of searching comp_dir, don't retry */
1906                         zfree(new_path);
1907                         return -errno;
1908                 }
1909
1910                 switch (errno) {
1911                 case ENAMETOOLONG:
1912                 case ENOENT:
1913                 case EROFS:
1914                 case EFAULT:
1915                         raw_path = strchr(++raw_path, '/');
1916                         if (!raw_path) {
1917                                 zfree(new_path);
1918                                 return -ENOENT;
1919                         }
1920                         continue;
1921
1922                 default:
1923                         zfree(new_path);
1924                         return -errno;
1925                 }
1926         }
1927 }