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Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[cris-mirror.git] / tools / perf / util / probe-finder.c
bloba5731de0e5ebc73ed3fbc35dd1b334e664f20b69
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 <inttypes.h>
23 #include <sys/utsname.h>
24 #include <sys/types.h>
25 #include <sys/stat.h>
26 #include <fcntl.h>
27 #include <errno.h>
28 #include <stdio.h>
29 #include <unistd.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 "dso.h"
38 #include "debug.h"
39 #include "intlist.h"
40 #include "util.h"
41 #include "strlist.h"
42 #include "symbol.h"
43 #include "probe-finder.h"
44 #include "probe-file.h"
45 #include "string2.h"
46
47 /* Kprobe tracer basic type is up to u64 */
48 #define MAX_BASIC_TYPE_BITS 64
49
50 /* Dwarf FL wrappers */
51 static char *debuginfo_path; /* Currently dummy */
52
53 static const Dwfl_Callbacks offline_callbacks = {
54 .find_debuginfo = dwfl_standard_find_debuginfo,
55 .debuginfo_path = &debuginfo_path,
56
57 .section_address = dwfl_offline_section_address,
58
59 /* We use this table for core files too. */
60 .find_elf = dwfl_build_id_find_elf,
61 };
62
63 /* Get a Dwarf from offline image */
64 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
65 const char *path)
66 {
67 int fd;
68
69 fd = open(path, O_RDONLY);
70 if (fd < 0)
71 return fd;
72
73 dbg->dwfl = dwfl_begin(&offline_callbacks);
74 if (!dbg->dwfl)
75 goto error;
76
77 dwfl_report_begin(dbg->dwfl);
78 dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
79 if (!dbg->mod)
80 goto error;
81
82 dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
83 if (!dbg->dbg)
84 goto error;
85
86 dwfl_report_end(dbg->dwfl, NULL, NULL);
87
88 return 0;
89 error:
90 if (dbg->dwfl)
91 dwfl_end(dbg->dwfl);
92 else
93 close(fd);
94 memset(dbg, 0, sizeof(*dbg));
95
96 return -ENOENT;
97 }
98
99 static struct debuginfo *__debuginfo__new(const char *path)
100 {
101 struct debuginfo *dbg = zalloc(sizeof(*dbg));
102 if (!dbg)
103 return NULL;
104
105 if (debuginfo__init_offline_dwarf(dbg, path) < 0)
106 zfree(&dbg);
107 if (dbg)
108 pr_debug("Open Debuginfo file: %s\n", path);
109 return dbg;
110 }
111
112 enum dso_binary_type distro_dwarf_types[] = {
113 DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
114 DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
115 DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
116 DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
117 DSO_BINARY_TYPE__NOT_FOUND,
118 };
119
120 struct debuginfo *debuginfo__new(const char *path)
121 {
122 enum dso_binary_type *type;
123 char buf[PATH_MAX], nil = '\0';
124 struct dso *dso;
125 struct debuginfo *dinfo = NULL;
126
127 /* Try to open distro debuginfo files */
128 dso = dso__new(path);
129 if (!dso)
130 goto out;
131
132 for (type = distro_dwarf_types;
133 !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
134 type++) {
135 if (dso__read_binary_type_filename(dso, *type, &nil,
136 buf, PATH_MAX) < 0)
137 continue;
138 dinfo = __debuginfo__new(buf);
139 }
140 dso__put(dso);
141
142 out:
143 /* if failed to open all distro debuginfo, open given binary */
144 return dinfo ? : __debuginfo__new(path);
145 }
146
147 void debuginfo__delete(struct debuginfo *dbg)
148 {
149 if (dbg) {
150 if (dbg->dwfl)
151 dwfl_end(dbg->dwfl);
152 free(dbg);
153 }
154 }
155
156 /*
157 * Probe finder related functions
158 */
159
160 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
161 {
162 struct probe_trace_arg_ref *ref;
163 ref = zalloc(sizeof(struct probe_trace_arg_ref));
164 if (ref != NULL)
165 ref->offset = offs;
166 return ref;
167 }
168
169 /*
170 * Convert a location into trace_arg.
171 * If tvar == NULL, this just checks variable can be converted.
172 * If fentry == true and vr_die is a parameter, do huristic search
173 * for the location fuzzed by function entry mcount.
174 */
175 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
176 Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
177 unsigned int machine,
178 struct probe_trace_arg *tvar)
179 {
180 Dwarf_Attribute attr;
181 Dwarf_Addr tmp = 0;
182 Dwarf_Op *op;
183 size_t nops;
184 unsigned int regn;
185 Dwarf_Word offs = 0;
186 bool ref = false;
187 const char *regs;
188 int ret, ret2 = 0;
189
190 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
191 goto static_var;
192
193 /* TODO: handle more than 1 exprs */
194 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
195 return -EINVAL; /* Broken DIE ? */
196 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
197 ret = dwarf_entrypc(sp_die, &tmp);
198 if (ret)
199 return -ENOENT;
200
201 if (probe_conf.show_location_range &&
202 (dwarf_tag(vr_die) == DW_TAG_variable)) {
203 ret2 = -ERANGE;
204 } else if (addr != tmp ||
205 dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
206 return -ENOENT;
207 }
208
209 ret = dwarf_highpc(sp_die, &tmp);
210 if (ret)
211 return -ENOENT;
212 /*
213 * This is fuzzed by fentry mcount. We try to find the
214 * parameter location at the earliest address.
215 */
216 for (addr += 1; addr <= tmp; addr++) {
217 if (dwarf_getlocation_addr(&attr, addr, &op,
218 &nops, 1) > 0)
219 goto found;
220 }
221 return -ENOENT;
222 }
223 found:
224 if (nops == 0)
225 /* TODO: Support const_value */
226 return -ENOENT;
227
228 if (op->atom == DW_OP_addr) {
229 static_var:
230 if (!tvar)
231 return ret2;
232 /* Static variables on memory (not stack), make @varname */
233 ret = strlen(dwarf_diename(vr_die));
234 tvar->value = zalloc(ret + 2);
235 if (tvar->value == NULL)
236 return -ENOMEM;
237 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
238 tvar->ref = alloc_trace_arg_ref((long)offs);
239 if (tvar->ref == NULL)
240 return -ENOMEM;
241 return ret2;
242 }
243
244 /* If this is based on frame buffer, set the offset */
245 if (op->atom == DW_OP_fbreg) {
246 if (fb_ops == NULL)
247 return -ENOTSUP;
248 ref = true;
249 offs = op->number;
250 op = &fb_ops[0];
251 }
252
253 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
254 regn = op->atom - DW_OP_breg0;
255 offs += op->number;
256 ref = true;
257 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
258 regn = op->atom - DW_OP_reg0;
259 } else if (op->atom == DW_OP_bregx) {
260 regn = op->number;
261 offs += op->number2;
262 ref = true;
263 } else if (op->atom == DW_OP_regx) {
264 regn = op->number;
265 } else {
266 pr_debug("DW_OP %x is not supported.\n", op->atom);
267 return -ENOTSUP;
268 }
269
270 if (!tvar)
271 return ret2;
272
273 regs = get_dwarf_regstr(regn, machine);
274 if (!regs) {
275 /* This should be a bug in DWARF or this tool */
276 pr_warning("Mapping for the register number %u "
277 "missing on this architecture.\n", regn);
278 return -ENOTSUP;
279 }
280
281 tvar->value = strdup(regs);
282 if (tvar->value == NULL)
283 return -ENOMEM;
284
285 if (ref) {
286 tvar->ref = alloc_trace_arg_ref((long)offs);
287 if (tvar->ref == NULL)
288 return -ENOMEM;
289 }
290 return ret2;
291 }
292
293 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
294
295 static int convert_variable_type(Dwarf_Die *vr_die,
296 struct probe_trace_arg *tvar,
297 const char *cast)
298 {
299 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
300 Dwarf_Die type;
301 char buf[16];
302 char sbuf[STRERR_BUFSIZE];
303 int bsize, boffs, total;
304 int ret;
305 char prefix;
306
307 /* TODO: check all types */
308 if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
309 strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
310 /* Non string type is OK */
311 /* and respect signedness/hexadecimal cast */
312 tvar->type = strdup(cast);
313 return (tvar->type == NULL) ? -ENOMEM : 0;
314 }
315
316 bsize = dwarf_bitsize(vr_die);
317 if (bsize > 0) {
318 /* This is a bitfield */
319 boffs = dwarf_bitoffset(vr_die);
320 total = dwarf_bytesize(vr_die);
321 if (boffs < 0 || total < 0)
322 return -ENOENT;
323 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
324 BYTES_TO_BITS(total));
325 goto formatted;
326 }
327
328 if (die_get_real_type(vr_die, &type) == NULL) {
329 pr_warning("Failed to get a type information of %s.\n",
330 dwarf_diename(vr_die));
331 return -ENOENT;
332 }
333
334 pr_debug("%s type is %s.\n",
335 dwarf_diename(vr_die), dwarf_diename(&type));
336
337 if (cast && strcmp(cast, "string") == 0) { /* String type */
338 ret = dwarf_tag(&type);
339 if (ret != DW_TAG_pointer_type &&
340 ret != DW_TAG_array_type) {
341 pr_warning("Failed to cast into string: "
342 "%s(%s) is not a pointer nor array.\n",
343 dwarf_diename(vr_die), dwarf_diename(&type));
344 return -EINVAL;
345 }
346 if (die_get_real_type(&type, &type) == NULL) {
347 pr_warning("Failed to get a type"
348 " information.\n");
349 return -ENOENT;
350 }
351 if (ret == DW_TAG_pointer_type) {
352 while (*ref_ptr)
353 ref_ptr = &(*ref_ptr)->next;
354 /* Add new reference with offset +0 */
355 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
356 if (*ref_ptr == NULL) {
357 pr_warning("Out of memory error\n");
358 return -ENOMEM;
359 }
360 }
361 if (!die_compare_name(&type, "char") &&
362 !die_compare_name(&type, "unsigned char")) {
363 pr_warning("Failed to cast into string: "
364 "%s is not (unsigned) char *.\n",
365 dwarf_diename(vr_die));
366 return -EINVAL;
367 }
368 tvar->type = strdup(cast);
369 return (tvar->type == NULL) ? -ENOMEM : 0;
370 }
371
372 if (cast && (strcmp(cast, "u") == 0))
373 prefix = 'u';
374 else if (cast && (strcmp(cast, "s") == 0))
375 prefix = 's';
376 else if (cast && (strcmp(cast, "x") == 0) &&
377 probe_type_is_available(PROBE_TYPE_X))
378 prefix = 'x';
379 else
380 prefix = die_is_signed_type(&type) ? 's' :
381 probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
382
383 ret = dwarf_bytesize(&type);
384 if (ret <= 0)
385 /* No size ... try to use default type */
386 return 0;
387 ret = BYTES_TO_BITS(ret);
388
389 /* Check the bitwidth */
390 if (ret > MAX_BASIC_TYPE_BITS) {
391 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
392 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
393 ret = MAX_BASIC_TYPE_BITS;
394 }
395 ret = snprintf(buf, 16, "%c%d", prefix, ret);
396
397 formatted:
398 if (ret < 0 || ret >= 16) {
399 if (ret >= 16)
400 ret = -E2BIG;
401 pr_warning("Failed to convert variable type: %s\n",
402 str_error_r(-ret, sbuf, sizeof(sbuf)));
403 return ret;
404 }
405 tvar->type = strdup(buf);
406 if (tvar->type == NULL)
407 return -ENOMEM;
408 return 0;
409 }
410
411 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
412 struct perf_probe_arg_field *field,
413 struct probe_trace_arg_ref **ref_ptr,
414 Dwarf_Die *die_mem)
415 {
416 struct probe_trace_arg_ref *ref = *ref_ptr;
417 Dwarf_Die type;
418 Dwarf_Word offs;
419 int ret, tag;
420
421 pr_debug("converting %s in %s\n", field->name, varname);
422 if (die_get_real_type(vr_die, &type) == NULL) {
423 pr_warning("Failed to get the type of %s.\n", varname);
424 return -ENOENT;
425 }
426 pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
427 tag = dwarf_tag(&type);
428
429 if (field->name[0] == '[' &&
430 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
431 if (field->next)
432 /* Save original type for next field */
433 memcpy(die_mem, &type, sizeof(*die_mem));
434 /* Get the type of this array */
435 if (die_get_real_type(&type, &type) == NULL) {
436 pr_warning("Failed to get the type of %s.\n", varname);
437 return -ENOENT;
438 }
439 pr_debug2("Array real type: (%x)\n",
440 (unsigned)dwarf_dieoffset(&type));
441 if (tag == DW_TAG_pointer_type) {
442 ref = zalloc(sizeof(struct probe_trace_arg_ref));
443 if (ref == NULL)
444 return -ENOMEM;
445 if (*ref_ptr)
446 (*ref_ptr)->next = ref;
447 else
448 *ref_ptr = ref;
449 }
450 ref->offset += dwarf_bytesize(&type) * field->index;
451 if (!field->next)
452 /* Save vr_die for converting types */
453 memcpy(die_mem, vr_die, sizeof(*die_mem));
454 goto next;
455 } else if (tag == DW_TAG_pointer_type) {
456 /* Check the pointer and dereference */
457 if (!field->ref) {
458 pr_err("Semantic error: %s must be referred by '->'\n",
459 field->name);
460 return -EINVAL;
461 }
462 /* Get the type pointed by this pointer */
463 if (die_get_real_type(&type, &type) == NULL) {
464 pr_warning("Failed to get the type of %s.\n", varname);
465 return -ENOENT;
466 }
467 /* Verify it is a data structure */
468 tag = dwarf_tag(&type);
469 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
470 pr_warning("%s is not a data structure nor a union.\n",
471 varname);
472 return -EINVAL;
473 }
474
475 ref = zalloc(sizeof(struct probe_trace_arg_ref));
476 if (ref == NULL)
477 return -ENOMEM;
478 if (*ref_ptr)
479 (*ref_ptr)->next = ref;
480 else
481 *ref_ptr = ref;
482 } else {
483 /* Verify it is a data structure */
484 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
485 pr_warning("%s is not a data structure nor a union.\n",
486 varname);
487 return -EINVAL;
488 }
489 if (field->name[0] == '[') {
490 pr_err("Semantic error: %s is not a pointer"
491 " nor array.\n", varname);
492 return -EINVAL;
493 }
494 /* While prcessing unnamed field, we don't care about this */
495 if (field->ref && dwarf_diename(vr_die)) {
496 pr_err("Semantic error: %s must be referred by '.'\n",
497 field->name);
498 return -EINVAL;
499 }
500 if (!ref) {
501 pr_warning("Structure on a register is not "
502 "supported yet.\n");
503 return -ENOTSUP;
504 }
505 }
506
507 if (die_find_member(&type, field->name, die_mem) == NULL) {
508 pr_warning("%s(type:%s) has no member %s.\n", varname,
509 dwarf_diename(&type), field->name);
510 return -EINVAL;
511 }
512
513 /* Get the offset of the field */
514 if (tag == DW_TAG_union_type) {
515 offs = 0;
516 } else {
517 ret = die_get_data_member_location(die_mem, &offs);
518 if (ret < 0) {
519 pr_warning("Failed to get the offset of %s.\n",
520 field->name);
521 return ret;
522 }
523 }
524 ref->offset += (long)offs;
525
526 /* If this member is unnamed, we need to reuse this field */
527 if (!dwarf_diename(die_mem))
528 return convert_variable_fields(die_mem, varname, field,
529 &ref, die_mem);
530
531 next:
532 /* Converting next field */
533 if (field->next)
534 return convert_variable_fields(die_mem, field->name,
535 field->next, &ref, die_mem);
536 else
537 return 0;
538 }
539
540 /* Show a variables in kprobe event format */
541 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
542 {
543 Dwarf_Die die_mem;
544 int ret;
545
546 pr_debug("Converting variable %s into trace event.\n",
547 dwarf_diename(vr_die));
548
549 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
550 &pf->sp_die, pf->machine, pf->tvar);
551 if (ret == -ENOENT || ret == -EINVAL) {
552 pr_err("Failed to find the location of the '%s' variable at this address.\n"
553 " Perhaps it has been optimized out.\n"
554 " Use -V with the --range option to show '%s' location range.\n",
555 pf->pvar->var, pf->pvar->var);
556 } else if (ret == -ENOTSUP)
557 pr_err("Sorry, we don't support this variable location yet.\n");
558 else if (ret == 0 && pf->pvar->field) {
559 ret = convert_variable_fields(vr_die, pf->pvar->var,
560 pf->pvar->field, &pf->tvar->ref,
561 &die_mem);
562 vr_die = &die_mem;
563 }
564 if (ret == 0)
565 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
566 /* *expr will be cached in libdw. Don't free it. */
567 return ret;
568 }
569
570 /* Find a variable in a scope DIE */
571 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
572 {
573 Dwarf_Die vr_die;
574 char *buf, *ptr;
575 int ret = 0;
576
577 /* Copy raw parameters */
578 if (!is_c_varname(pf->pvar->var))
579 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
580
581 if (pf->pvar->name)
582 pf->tvar->name = strdup(pf->pvar->name);
583 else {
584 buf = synthesize_perf_probe_arg(pf->pvar);
585 if (!buf)
586 return -ENOMEM;
587 ptr = strchr(buf, ':'); /* Change type separator to _ */
588 if (ptr)
589 *ptr = '_';
590 pf->tvar->name = buf;
591 }
592 if (pf->tvar->name == NULL)
593 return -ENOMEM;
594
595 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
596 /* Search child die for local variables and parameters. */
597 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
598 /* Search again in global variables */
599 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
600 0, &vr_die)) {
601 pr_warning("Failed to find '%s' in this function.\n",
602 pf->pvar->var);
603 ret = -ENOENT;
604 }
605 }
606 if (ret >= 0)
607 ret = convert_variable(&vr_die, pf);
608
609 return ret;
610 }
611
612 /* Convert subprogram DIE to trace point */
613 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
614 Dwarf_Addr paddr, bool retprobe,
615 const char *function,
616 struct probe_trace_point *tp)
617 {
618 Dwarf_Addr eaddr, highaddr;
619 GElf_Sym sym;
620 const char *symbol;
621
622 /* Verify the address is correct */
623 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
624 pr_warning("Failed to get entry address of %s\n",
625 dwarf_diename(sp_die));
626 return -ENOENT;
627 }
628 if (dwarf_highpc(sp_die, &highaddr) != 0) {
629 pr_warning("Failed to get end address of %s\n",
630 dwarf_diename(sp_die));
631 return -ENOENT;
632 }
633 if (paddr > highaddr) {
634 pr_warning("Offset specified is greater than size of %s\n",
635 dwarf_diename(sp_die));
636 return -EINVAL;
637 }
638
639 symbol = dwarf_diename(sp_die);
640 if (!symbol) {
641 /* Try to get the symbol name from symtab */
642 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
643 if (!symbol) {
644 pr_warning("Failed to find symbol at 0x%lx\n",
645 (unsigned long)paddr);
646 return -ENOENT;
647 }
648 eaddr = sym.st_value;
649 }
650 tp->offset = (unsigned long)(paddr - eaddr);
651 tp->address = (unsigned long)paddr;
652 tp->symbol = strdup(symbol);
653 if (!tp->symbol)
654 return -ENOMEM;
655
656 /* Return probe must be on the head of a subprogram */
657 if (retprobe) {
658 if (eaddr != paddr) {
659 pr_warning("Failed to find \"%s%%return\",\n"
660 " because %s is an inlined function and"
661 " has no return point.\n", function,
662 function);
663 return -EINVAL;
664 }
665 tp->retprobe = true;
666 }
667
668 return 0;
669 }
670
671 /* Call probe_finder callback with scope DIE */
672 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
673 {
674 Dwarf_Attribute fb_attr;
675 Dwarf_Frame *frame = NULL;
676 size_t nops;
677 int ret;
678
679 if (!sc_die) {
680 pr_err("Caller must pass a scope DIE. Program error.\n");
681 return -EINVAL;
682 }
683
684 /* If not a real subprogram, find a real one */
685 if (!die_is_func_def(sc_die)) {
686 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
687 if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
688 pr_warning("Ignoring tail call from %s\n",
689 dwarf_diename(&pf->sp_die));
690 return 0;
691 } else {
692 pr_warning("Failed to find probe point in any "
693 "functions.\n");
694 return -ENOENT;
695 }
696 }
697 } else
698 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
699
700 /* Get the frame base attribute/ops from subprogram */
701 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
702 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
703 if (ret <= 0 || nops == 0) {
704 pf->fb_ops = NULL;
705 #if _ELFUTILS_PREREQ(0, 142)
706 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
707 (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
708 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
709 (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
710 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
711 pr_warning("Failed to get call frame on 0x%jx\n",
712 (uintmax_t)pf->addr);
713 free(frame);
714 return -ENOENT;
715 }
716 #endif
717 }
718
719 /* Call finder's callback handler */
720 ret = pf->callback(sc_die, pf);
721
722 /* Since *pf->fb_ops can be a part of frame. we should free it here. */
723 free(frame);
724 pf->fb_ops = NULL;
725
726 return ret;
727 }
728
729 struct find_scope_param {
730 const char *function;
731 const char *file;
732 int line;
733 int diff;
734 Dwarf_Die *die_mem;
735 bool found;
736 };
737
738 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
739 {
740 struct find_scope_param *fsp = data;
741 const char *file;
742 int lno;
743
744 /* Skip if declared file name does not match */
745 if (fsp->file) {
746 file = dwarf_decl_file(fn_die);
747 if (!file || strcmp(fsp->file, file) != 0)
748 return 0;
749 }
750 /* If the function name is given, that's what user expects */
751 if (fsp->function) {
752 if (die_match_name(fn_die, fsp->function)) {
753 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
754 fsp->found = true;
755 return 1;
756 }
757 } else {
758 /* With the line number, find the nearest declared DIE */
759 dwarf_decl_line(fn_die, &lno);
760 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
761 /* Keep a candidate and continue */
762 fsp->diff = fsp->line - lno;
763 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
764 fsp->found = true;
765 }
766 }
767 return 0;
768 }
769
770 /* Find an appropriate scope fits to given conditions */
771 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
772 {
773 struct find_scope_param fsp = {
774 .function = pf->pev->point.function,
775 .file = pf->fname,
776 .line = pf->lno,
777 .diff = INT_MAX,
778 .die_mem = die_mem,
779 .found = false,
780 };
781
782 cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
783
784 return fsp.found ? die_mem : NULL;
785 }
786
787 static int probe_point_line_walker(const char *fname, int lineno,
788 Dwarf_Addr addr, void *data)
789 {
790 struct probe_finder *pf = data;
791 Dwarf_Die *sc_die, die_mem;
792 int ret;
793
794 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
795 return 0;
796
797 pf->addr = addr;
798 sc_die = find_best_scope(pf, &die_mem);
799 if (!sc_die) {
800 pr_warning("Failed to find scope of probe point.\n");
801 return -ENOENT;
802 }
803
804 ret = call_probe_finder(sc_die, pf);
805
806 /* Continue if no error, because the line will be in inline function */
807 return ret < 0 ? ret : 0;
808 }
809
810 /* Find probe point from its line number */
811 static int find_probe_point_by_line(struct probe_finder *pf)
812 {
813 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
814 }
815
816 /* Find lines which match lazy pattern */
817 static int find_lazy_match_lines(struct intlist *list,
818 const char *fname, const char *pat)
819 {
820 FILE *fp;
821 char *line = NULL;
822 size_t line_len;
823 ssize_t len;
824 int count = 0, linenum = 1;
825 char sbuf[STRERR_BUFSIZE];
826
827 fp = fopen(fname, "r");
828 if (!fp) {
829 pr_warning("Failed to open %s: %s\n", fname,
830 str_error_r(errno, sbuf, sizeof(sbuf)));
831 return -errno;
832 }
833
834 while ((len = getline(&line, &line_len, fp)) > 0) {
835
836 if (line[len - 1] == '\n')
837 line[len - 1] = '\0';
838
839 if (strlazymatch(line, pat)) {
840 intlist__add(list, linenum);
841 count++;
842 }
843 linenum++;
844 }
845
846 if (ferror(fp))
847 count = -errno;
848 free(line);
849 fclose(fp);
850
851 if (count == 0)
852 pr_debug("No matched lines found in %s.\n", fname);
853 return count;
854 }
855
856 static int probe_point_lazy_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 (!intlist__has_entry(pf->lcache, lineno) ||
864 strtailcmp(fname, pf->fname) != 0)
865 return 0;
866
867 pr_debug("Probe line found: line:%d addr:0x%llx\n",
868 lineno, (unsigned long long)addr);
869 pf->addr = addr;
870 pf->lno = lineno;
871 sc_die = find_best_scope(pf, &die_mem);
872 if (!sc_die) {
873 pr_warning("Failed to find scope of probe point.\n");
874 return -ENOENT;
875 }
876
877 ret = call_probe_finder(sc_die, pf);
878
879 /*
880 * Continue if no error, because the lazy pattern will match
881 * to other lines
882 */
883 return ret < 0 ? ret : 0;
884 }
885
886 /* Find probe points from lazy pattern */
887 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
888 {
889 int ret = 0;
890 char *fpath;
891
892 if (intlist__empty(pf->lcache)) {
893 const char *comp_dir;
894
895 comp_dir = cu_get_comp_dir(&pf->cu_die);
896 ret = get_real_path(pf->fname, comp_dir, &fpath);
897 if (ret < 0) {
898 pr_warning("Failed to find source file path.\n");
899 return ret;
900 }
901
902 /* Matching lazy line pattern */
903 ret = find_lazy_match_lines(pf->lcache, fpath,
904 pf->pev->point.lazy_line);
905 free(fpath);
906 if (ret <= 0)
907 return ret;
908 }
909
910 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
911 }
912
913 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
914 {
915 struct perf_probe_point *pp = &pf->pev->point;
916
917 /* Not uprobe? */
918 if (!pf->pev->uprobes)
919 return;
920
921 /* Compiled with optimization? */
922 if (die_is_optimized_target(&pf->cu_die))
923 return;
924
925 /* Don't know entrypc? */
926 if (!pf->addr)
927 return;
928
929 /* Only FUNC and FUNC@SRC are eligible. */
930 if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
931 pp->offset || pp->abs_address)
932 return;
933
934 /* Not interested in func parameter? */
935 if (!perf_probe_with_var(pf->pev))
936 return;
937
938 pr_info("Target program is compiled without optimization. Skipping prologue.\n"
939 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
940 pf->addr);
941
942 die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
943 }
944
945 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
946 {
947 struct probe_finder *pf = data;
948 struct perf_probe_point *pp = &pf->pev->point;
949 Dwarf_Addr addr;
950 int ret;
951
952 if (pp->lazy_line)
953 ret = find_probe_point_lazy(in_die, pf);
954 else {
955 /* Get probe address */
956 if (dwarf_entrypc(in_die, &addr) != 0) {
957 pr_warning("Failed to get entry address of %s.\n",
958 dwarf_diename(in_die));
959 return -ENOENT;
960 }
961 if (addr == 0) {
962 pr_debug("%s has no valid entry address. skipped.\n",
963 dwarf_diename(in_die));
964 return -ENOENT;
965 }
966 pf->addr = addr;
967 pf->addr += pp->offset;
968 pr_debug("found inline addr: 0x%jx\n",
969 (uintmax_t)pf->addr);
970
971 ret = call_probe_finder(in_die, pf);
972 }
973
974 return ret;
975 }
976
977 /* Callback parameter with return value for libdw */
978 struct dwarf_callback_param {
979 void *data;
980 int retval;
981 };
982
983 /* Search function from function name */
984 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
985 {
986 struct dwarf_callback_param *param = data;
987 struct probe_finder *pf = param->data;
988 struct perf_probe_point *pp = &pf->pev->point;
989
990 /* Check tag and diename */
991 if (!die_is_func_def(sp_die) ||
992 !die_match_name(sp_die, pp->function))
993 return DWARF_CB_OK;
994
995 /* Check declared file */
996 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
997 return DWARF_CB_OK;
998
999 pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
1000 (unsigned long)dwarf_dieoffset(sp_die));
1001 pf->fname = dwarf_decl_file(sp_die);
1002 if (pp->line) { /* Function relative line */
1003 dwarf_decl_line(sp_die, &pf->lno);
1004 pf->lno += pp->line;
1005 param->retval = find_probe_point_by_line(pf);
1006 } else if (die_is_func_instance(sp_die)) {
1007 /* Instances always have the entry address */
1008 dwarf_entrypc(sp_die, &pf->addr);
1009 /* But in some case the entry address is 0 */
1010 if (pf->addr == 0) {
1011 pr_debug("%s has no entry PC. Skipped\n",
1012 dwarf_diename(sp_die));
1013 param->retval = 0;
1014 /* Real function */
1015 } else if (pp->lazy_line)
1016 param->retval = find_probe_point_lazy(sp_die, pf);
1017 else {
1018 skip_prologue(sp_die, pf);
1019 pf->addr += pp->offset;
1020 /* TODO: Check the address in this function */
1021 param->retval = call_probe_finder(sp_die, pf);
1022 }
1023 } else if (!probe_conf.no_inlines) {
1024 /* Inlined function: search instances */
1025 param->retval = die_walk_instances(sp_die,
1026 probe_point_inline_cb, (void *)pf);
1027 /* This could be a non-existed inline definition */
1028 if (param->retval == -ENOENT)
1029 param->retval = 0;
1030 }
1031
1032 /* We need to find other candidates */
1033 if (strisglob(pp->function) && param->retval >= 0) {
1034 param->retval = 0; /* We have to clear the result */
1035 return DWARF_CB_OK;
1036 }
1037
1038 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1039 }
1040
1041 static int find_probe_point_by_func(struct probe_finder *pf)
1042 {
1043 struct dwarf_callback_param _param = {.data = (void *)pf,
1044 .retval = 0};
1045 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1046 return _param.retval;
1047 }
1048
1049 struct pubname_callback_param {
1050 char *function;
1051 char *file;
1052 Dwarf_Die *cu_die;
1053 Dwarf_Die *sp_die;
1054 int found;
1055 };
1056
1057 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1058 {
1059 struct pubname_callback_param *param = data;
1060
1061 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1062 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1063 return DWARF_CB_OK;
1064
1065 if (die_match_name(param->sp_die, param->function)) {
1066 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1067 return DWARF_CB_OK;
1068
1069 if (param->file &&
1070 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1071 return DWARF_CB_OK;
1072
1073 param->found = 1;
1074 return DWARF_CB_ABORT;
1075 }
1076 }
1077
1078 return DWARF_CB_OK;
1079 }
1080
1081 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1082 struct probe_finder *pf)
1083 {
1084 struct perf_probe_point *pp = &pf->pev->point;
1085 Dwarf_Off off, noff;
1086 size_t cuhl;
1087 Dwarf_Die *diep;
1088 int ret = 0;
1089
1090 off = 0;
1091 pf->lcache = intlist__new(NULL);
1092 if (!pf->lcache)
1093 return -ENOMEM;
1094
1095 /* Fastpath: lookup by function name from .debug_pubnames section */
1096 if (pp->function && !strisglob(pp->function)) {
1097 struct pubname_callback_param pubname_param = {
1098 .function = pp->function,
1099 .file = pp->file,
1100 .cu_die = &pf->cu_die,
1101 .sp_die = &pf->sp_die,
1102 .found = 0,
1103 };
1104 struct dwarf_callback_param probe_param = {
1105 .data = pf,
1106 };
1107
1108 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1109 &pubname_param, 0);
1110 if (pubname_param.found) {
1111 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1112 if (ret)
1113 goto found;
1114 }
1115 }
1116
1117 /* Loop on CUs (Compilation Unit) */
1118 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1119 /* Get the DIE(Debugging Information Entry) of this CU */
1120 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1121 if (!diep)
1122 continue;
1123
1124 /* Check if target file is included. */
1125 if (pp->file)
1126 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1127 else
1128 pf->fname = NULL;
1129
1130 if (!pp->file || pf->fname) {
1131 if (pp->function)
1132 ret = find_probe_point_by_func(pf);
1133 else if (pp->lazy_line)
1134 ret = find_probe_point_lazy(&pf->cu_die, pf);
1135 else {
1136 pf->lno = pp->line;
1137 ret = find_probe_point_by_line(pf);
1138 }
1139 if (ret < 0)
1140 break;
1141 }
1142 off = noff;
1143 }
1144
1145 found:
1146 intlist__delete(pf->lcache);
1147 pf->lcache = NULL;
1148
1149 return ret;
1150 }
1151
1152 /* Find probe points from debuginfo */
1153 static int debuginfo__find_probes(struct debuginfo *dbg,
1154 struct probe_finder *pf)
1155 {
1156 int ret = 0;
1157 Elf *elf;
1158 GElf_Ehdr ehdr;
1159
1160 if (pf->cfi_eh || pf->cfi_dbg)
1161 return debuginfo__find_probe_location(dbg, pf);
1162
1163 /* Get the call frame information from this dwarf */
1164 elf = dwarf_getelf(dbg->dbg);
1165 if (elf == NULL)
1166 return -EINVAL;
1167
1168 if (gelf_getehdr(elf, &ehdr) == NULL)
1169 return -EINVAL;
1170
1171 pf->machine = ehdr.e_machine;
1172
1173 #if _ELFUTILS_PREREQ(0, 142)
1174 do {
1175 GElf_Shdr shdr;
1176
1177 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1178 shdr.sh_type == SHT_PROGBITS)
1179 pf->cfi_eh = dwarf_getcfi_elf(elf);
1180
1181 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1182 } while (0);
1183 #endif
1184
1185 ret = debuginfo__find_probe_location(dbg, pf);
1186 return ret;
1187 }
1188
1189 struct local_vars_finder {
1190 struct probe_finder *pf;
1191 struct perf_probe_arg *args;
1192 bool vars;
1193 int max_args;
1194 int nargs;
1195 int ret;
1196 };
1197
1198 /* Collect available variables in this scope */
1199 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1200 {
1201 struct local_vars_finder *vf = data;
1202 struct probe_finder *pf = vf->pf;
1203 int tag;
1204
1205 tag = dwarf_tag(die_mem);
1206 if (tag == DW_TAG_formal_parameter ||
1207 (tag == DW_TAG_variable && vf->vars)) {
1208 if (convert_variable_location(die_mem, vf->pf->addr,
1209 vf->pf->fb_ops, &pf->sp_die,
1210 pf->machine, NULL) == 0) {
1211 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1212 if (vf->args[vf->nargs].var == NULL) {
1213 vf->ret = -ENOMEM;
1214 return DIE_FIND_CB_END;
1215 }
1216 pr_debug(" %s", vf->args[vf->nargs].var);
1217 vf->nargs++;
1218 }
1219 }
1220
1221 if (dwarf_haspc(die_mem, vf->pf->addr))
1222 return DIE_FIND_CB_CONTINUE;
1223 else
1224 return DIE_FIND_CB_SIBLING;
1225 }
1226
1227 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1228 struct perf_probe_arg *args)
1229 {
1230 Dwarf_Die die_mem;
1231 int i;
1232 int n = 0;
1233 struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1234 .max_args = MAX_PROBE_ARGS, .ret = 0};
1235
1236 for (i = 0; i < pf->pev->nargs; i++) {
1237 /* var never be NULL */
1238 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1239 vf.vars = true;
1240 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1241 /* Copy normal argument */
1242 args[n] = pf->pev->args[i];
1243 n++;
1244 continue;
1245 }
1246 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1247 vf.nargs = n;
1248 /* Special local variables */
1249 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1250 &die_mem);
1251 pr_debug(" (%d)\n", vf.nargs - n);
1252 if (vf.ret < 0)
1253 return vf.ret;
1254 n = vf.nargs;
1255 }
1256 return n;
1257 }
1258
1259 /* Add a found probe point into trace event list */
1260 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1261 {
1262 struct trace_event_finder *tf =
1263 container_of(pf, struct trace_event_finder, pf);
1264 struct perf_probe_point *pp = &pf->pev->point;
1265 struct probe_trace_event *tev;
1266 struct perf_probe_arg *args = NULL;
1267 int ret, i;
1268
1269 /* Check number of tevs */
1270 if (tf->ntevs == tf->max_tevs) {
1271 pr_warning("Too many( > %d) probe point found.\n",
1272 tf->max_tevs);
1273 return -ERANGE;
1274 }
1275 tev = &tf->tevs[tf->ntevs++];
1276
1277 /* Trace point should be converted from subprogram DIE */
1278 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1279 pp->retprobe, pp->function, &tev->point);
1280 if (ret < 0)
1281 goto end;
1282
1283 tev->point.realname = strdup(dwarf_diename(sc_die));
1284 if (!tev->point.realname) {
1285 ret = -ENOMEM;
1286 goto end;
1287 }
1288
1289 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1290 tev->point.offset);
1291
1292 /* Expand special probe argument if exist */
1293 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1294 if (args == NULL) {
1295 ret = -ENOMEM;
1296 goto end;
1297 }
1298
1299 ret = expand_probe_args(sc_die, pf, args);
1300 if (ret < 0)
1301 goto end;
1302
1303 tev->nargs = ret;
1304 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1305 if (tev->args == NULL) {
1306 ret = -ENOMEM;
1307 goto end;
1308 }
1309
1310 /* Find each argument */
1311 for (i = 0; i < tev->nargs; i++) {
1312 pf->pvar = &args[i];
1313 pf->tvar = &tev->args[i];
1314 /* Variable should be found from scope DIE */
1315 ret = find_variable(sc_die, pf);
1316 if (ret != 0)
1317 break;
1318 }
1319
1320 end:
1321 if (ret) {
1322 clear_probe_trace_event(tev);
1323 tf->ntevs--;
1324 }
1325 free(args);
1326 return ret;
1327 }
1328
1329 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1330 int debuginfo__find_trace_events(struct debuginfo *dbg,
1331 struct perf_probe_event *pev,
1332 struct probe_trace_event **tevs)
1333 {
1334 struct trace_event_finder tf = {
1335 .pf = {.pev = pev, .callback = add_probe_trace_event},
1336 .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1337 int ret, i;
1338
1339 /* Allocate result tevs array */
1340 *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1341 if (*tevs == NULL)
1342 return -ENOMEM;
1343
1344 tf.tevs = *tevs;
1345 tf.ntevs = 0;
1346
1347 ret = debuginfo__find_probes(dbg, &tf.pf);
1348 if (ret < 0) {
1349 for (i = 0; i < tf.ntevs; i++)
1350 clear_probe_trace_event(&tf.tevs[i]);
1351 zfree(tevs);
1352 return ret;
1353 }
1354
1355 return (ret < 0) ? ret : tf.ntevs;
1356 }
1357
1358 /* Collect available variables in this scope */
1359 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1360 {
1361 struct available_var_finder *af = data;
1362 struct variable_list *vl;
1363 struct strbuf buf = STRBUF_INIT;
1364 int tag, ret;
1365
1366 vl = &af->vls[af->nvls - 1];
1367
1368 tag = dwarf_tag(die_mem);
1369 if (tag == DW_TAG_formal_parameter ||
1370 tag == DW_TAG_variable) {
1371 ret = convert_variable_location(die_mem, af->pf.addr,
1372 af->pf.fb_ops, &af->pf.sp_die,
1373 af->pf.machine, NULL);
1374 if (ret == 0 || ret == -ERANGE) {
1375 int ret2;
1376 bool externs = !af->child;
1377
1378 if (strbuf_init(&buf, 64) < 0)
1379 goto error;
1380
1381 if (probe_conf.show_location_range) {
1382 if (!externs)
1383 ret2 = strbuf_add(&buf,
1384 ret ? "[INV]\t" : "[VAL]\t", 6);
1385 else
1386 ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1387 if (ret2)
1388 goto error;
1389 }
1390
1391 ret2 = die_get_varname(die_mem, &buf);
1392
1393 if (!ret2 && probe_conf.show_location_range &&
1394 !externs) {
1395 if (strbuf_addch(&buf, '\t') < 0)
1396 goto error;
1397 ret2 = die_get_var_range(&af->pf.sp_die,
1398 die_mem, &buf);
1399 }
1400
1401 pr_debug("Add new var: %s\n", buf.buf);
1402 if (ret2 == 0) {
1403 strlist__add(vl->vars,
1404 strbuf_detach(&buf, NULL));
1405 }
1406 strbuf_release(&buf);
1407 }
1408 }
1409
1410 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1411 return DIE_FIND_CB_CONTINUE;
1412 else
1413 return DIE_FIND_CB_SIBLING;
1414 error:
1415 strbuf_release(&buf);
1416 pr_debug("Error in strbuf\n");
1417 return DIE_FIND_CB_END;
1418 }
1419
1420 /* Add a found vars into available variables list */
1421 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1422 {
1423 struct available_var_finder *af =
1424 container_of(pf, struct available_var_finder, pf);
1425 struct perf_probe_point *pp = &pf->pev->point;
1426 struct variable_list *vl;
1427 Dwarf_Die die_mem;
1428 int ret;
1429
1430 /* Check number of tevs */
1431 if (af->nvls == af->max_vls) {
1432 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1433 return -ERANGE;
1434 }
1435 vl = &af->vls[af->nvls++];
1436
1437 /* Trace point should be converted from subprogram DIE */
1438 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1439 pp->retprobe, pp->function, &vl->point);
1440 if (ret < 0)
1441 return ret;
1442
1443 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1444 vl->point.offset);
1445
1446 /* Find local variables */
1447 vl->vars = strlist__new(NULL, NULL);
1448 if (vl->vars == NULL)
1449 return -ENOMEM;
1450 af->child = true;
1451 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1452
1453 /* Find external variables */
1454 if (!probe_conf.show_ext_vars)
1455 goto out;
1456 /* Don't need to search child DIE for external vars. */
1457 af->child = false;
1458 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1459
1460 out:
1461 if (strlist__empty(vl->vars)) {
1462 strlist__delete(vl->vars);
1463 vl->vars = NULL;
1464 }
1465
1466 return ret;
1467 }
1468
1469 /*
1470 * Find available variables at given probe point
1471 * Return the number of found probe points. Return 0 if there is no
1472 * matched probe point. Return <0 if an error occurs.
1473 */
1474 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1475 struct perf_probe_event *pev,
1476 struct variable_list **vls)
1477 {
1478 struct available_var_finder af = {
1479 .pf = {.pev = pev, .callback = add_available_vars},
1480 .mod = dbg->mod,
1481 .max_vls = probe_conf.max_probes};
1482 int ret;
1483
1484 /* Allocate result vls array */
1485 *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1486 if (*vls == NULL)
1487 return -ENOMEM;
1488
1489 af.vls = *vls;
1490 af.nvls = 0;
1491
1492 ret = debuginfo__find_probes(dbg, &af.pf);
1493 if (ret < 0) {
1494 /* Free vlist for error */
1495 while (af.nvls--) {
1496 zfree(&af.vls[af.nvls].point.symbol);
1497 strlist__delete(af.vls[af.nvls].vars);
1498 }
1499 zfree(vls);
1500 return ret;
1501 }
1502
1503 return (ret < 0) ? ret : af.nvls;
1504 }
1505
1506 /* For the kernel module, we need a special code to get a DIE */
1507 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1508 bool adjust_offset)
1509 {
1510 int n, i;
1511 Elf32_Word shndx;
1512 Elf_Scn *scn;
1513 Elf *elf;
1514 GElf_Shdr mem, *shdr;
1515 const char *p;
1516
1517 elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1518 if (!elf)
1519 return -EINVAL;
1520
1521 /* Get the number of relocations */
1522 n = dwfl_module_relocations(dbg->mod);
1523 if (n < 0)
1524 return -ENOENT;
1525 /* Search the relocation related .text section */
1526 for (i = 0; i < n; i++) {
1527 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1528 if (strcmp(p, ".text") == 0) {
1529 /* OK, get the section header */
1530 scn = elf_getscn(elf, shndx);
1531 if (!scn)
1532 return -ENOENT;
1533 shdr = gelf_getshdr(scn, &mem);
1534 if (!shdr)
1535 return -ENOENT;
1536 *offs = shdr->sh_addr;
1537 if (adjust_offset)
1538 *offs -= shdr->sh_offset;
1539 }
1540 }
1541 return 0;
1542 }
1543
1544 /* Reverse search */
1545 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1546 struct perf_probe_point *ppt)
1547 {
1548 Dwarf_Die cudie, spdie, indie;
1549 Dwarf_Addr _addr = 0, baseaddr = 0;
1550 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1551 int baseline = 0, lineno = 0, ret = 0;
1552
1553 /* We always need to relocate the address for aranges */
1554 if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1555 addr += baseaddr;
1556 /* Find cu die */
1557 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1558 pr_warning("Failed to find debug information for address %lx\n",
1559 addr);
1560 ret = -EINVAL;
1561 goto end;
1562 }
1563
1564 /* Find a corresponding line (filename and lineno) */
1565 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1566 /* Don't care whether it failed or not */
1567
1568 /* Find a corresponding function (name, baseline and baseaddr) */
1569 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1570 /* Get function entry information */
1571 func = basefunc = dwarf_diename(&spdie);
1572 if (!func ||
1573 dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1574 dwarf_decl_line(&spdie, &baseline) != 0) {
1575 lineno = 0;
1576 goto post;
1577 }
1578
1579 fname = dwarf_decl_file(&spdie);
1580 if (addr == (unsigned long)baseaddr) {
1581 /* Function entry - Relative line number is 0 */
1582 lineno = baseline;
1583 goto post;
1584 }
1585
1586 /* Track down the inline functions step by step */
1587 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1588 &indie)) {
1589 /* There is an inline function */
1590 if (dwarf_entrypc(&indie, &_addr) == 0 &&
1591 _addr == addr) {
1592 /*
1593 * addr is at an inline function entry.
1594 * In this case, lineno should be the call-site
1595 * line number. (overwrite lineinfo)
1596 */
1597 lineno = die_get_call_lineno(&indie);
1598 fname = die_get_call_file(&indie);
1599 break;
1600 } else {
1601 /*
1602 * addr is in an inline function body.
1603 * Since lineno points one of the lines
1604 * of the inline function, baseline should
1605 * be the entry line of the inline function.
1606 */
1607 tmp = dwarf_diename(&indie);
1608 if (!tmp ||
1609 dwarf_decl_line(&indie, &baseline) != 0)
1610 break;
1611 func = tmp;
1612 spdie = indie;
1613 }
1614 }
1615 /* Verify the lineno and baseline are in a same file */
1616 tmp = dwarf_decl_file(&spdie);
1617 if (!tmp || strcmp(tmp, fname) != 0)
1618 lineno = 0;
1619 }
1620
1621 post:
1622 /* Make a relative line number or an offset */
1623 if (lineno)
1624 ppt->line = lineno - baseline;
1625 else if (basefunc) {
1626 ppt->offset = addr - (unsigned long)baseaddr;
1627 func = basefunc;
1628 }
1629
1630 /* Duplicate strings */
1631 if (func) {
1632 ppt->function = strdup(func);
1633 if (ppt->function == NULL) {
1634 ret = -ENOMEM;
1635 goto end;
1636 }
1637 }
1638 if (fname) {
1639 ppt->file = strdup(fname);
1640 if (ppt->file == NULL) {
1641 zfree(&ppt->function);
1642 ret = -ENOMEM;
1643 goto end;
1644 }
1645 }
1646 end:
1647 if (ret == 0 && (fname || func))
1648 ret = 1; /* Found a point */
1649 return ret;
1650 }
1651
1652 /* Add a line and store the src path */
1653 static int line_range_add_line(const char *src, unsigned int lineno,
1654 struct line_range *lr)
1655 {
1656 /* Copy source path */
1657 if (!lr->path) {
1658 lr->path = strdup(src);
1659 if (lr->path == NULL)
1660 return -ENOMEM;
1661 }
1662 return intlist__add(lr->line_list, lineno);
1663 }
1664
1665 static int line_range_walk_cb(const char *fname, int lineno,
1666 Dwarf_Addr addr __maybe_unused,
1667 void *data)
1668 {
1669 struct line_finder *lf = data;
1670 int err;
1671
1672 if ((strtailcmp(fname, lf->fname) != 0) ||
1673 (lf->lno_s > lineno || lf->lno_e < lineno))
1674 return 0;
1675
1676 err = line_range_add_line(fname, lineno, lf->lr);
1677 if (err < 0 && err != -EEXIST)
1678 return err;
1679
1680 return 0;
1681 }
1682
1683 /* Find line range from its line number */
1684 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1685 {
1686 int ret;
1687
1688 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1689
1690 /* Update status */
1691 if (ret >= 0)
1692 if (!intlist__empty(lf->lr->line_list))
1693 ret = lf->found = 1;
1694 else
1695 ret = 0; /* Lines are not found */
1696 else {
1697 zfree(&lf->lr->path);
1698 }
1699 return ret;
1700 }
1701
1702 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1703 {
1704 int ret = find_line_range_by_line(in_die, data);
1705
1706 /*
1707 * We have to check all instances of inlined function, because
1708 * some execution paths can be optimized out depends on the
1709 * function argument of instances. However, if an error occurs,
1710 * it should be handled by the caller.
1711 */
1712 return ret < 0 ? ret : 0;
1713 }
1714
1715 /* Search function definition from function name */
1716 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1717 {
1718 struct dwarf_callback_param *param = data;
1719 struct line_finder *lf = param->data;
1720 struct line_range *lr = lf->lr;
1721
1722 /* Check declared file */
1723 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1724 return DWARF_CB_OK;
1725
1726 if (die_is_func_def(sp_die) &&
1727 die_match_name(sp_die, lr->function)) {
1728 lf->fname = dwarf_decl_file(sp_die);
1729 dwarf_decl_line(sp_die, &lr->offset);
1730 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1731 lf->lno_s = lr->offset + lr->start;
1732 if (lf->lno_s < 0) /* Overflow */
1733 lf->lno_s = INT_MAX;
1734 lf->lno_e = lr->offset + lr->end;
1735 if (lf->lno_e < 0) /* Overflow */
1736 lf->lno_e = INT_MAX;
1737 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1738 lr->start = lf->lno_s;
1739 lr->end = lf->lno_e;
1740 if (!die_is_func_instance(sp_die))
1741 param->retval = die_walk_instances(sp_die,
1742 line_range_inline_cb, lf);
1743 else
1744 param->retval = find_line_range_by_line(sp_die, lf);
1745 return DWARF_CB_ABORT;
1746 }
1747 return DWARF_CB_OK;
1748 }
1749
1750 static int find_line_range_by_func(struct line_finder *lf)
1751 {
1752 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1753 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1754 return param.retval;
1755 }
1756
1757 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1758 {
1759 struct line_finder lf = {.lr = lr, .found = 0};
1760 int ret = 0;
1761 Dwarf_Off off = 0, noff;
1762 size_t cuhl;
1763 Dwarf_Die *diep;
1764 const char *comp_dir;
1765
1766 /* Fastpath: lookup by function name from .debug_pubnames section */
1767 if (lr->function) {
1768 struct pubname_callback_param pubname_param = {
1769 .function = lr->function, .file = lr->file,
1770 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1771 struct dwarf_callback_param line_range_param = {
1772 .data = (void *)&lf, .retval = 0};
1773
1774 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1775 &pubname_param, 0);
1776 if (pubname_param.found) {
1777 line_range_search_cb(&lf.sp_die, &line_range_param);
1778 if (lf.found)
1779 goto found;
1780 }
1781 }
1782
1783 /* Loop on CUs (Compilation Unit) */
1784 while (!lf.found && ret >= 0) {
1785 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1786 NULL, NULL, NULL) != 0)
1787 break;
1788
1789 /* Get the DIE(Debugging Information Entry) of this CU */
1790 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1791 if (!diep)
1792 continue;
1793
1794 /* Check if target file is included. */
1795 if (lr->file)
1796 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1797 else
1798 lf.fname = 0;
1799
1800 if (!lr->file || lf.fname) {
1801 if (lr->function)
1802 ret = find_line_range_by_func(&lf);
1803 else {
1804 lf.lno_s = lr->start;
1805 lf.lno_e = lr->end;
1806 ret = find_line_range_by_line(NULL, &lf);
1807 }
1808 }
1809 off = noff;
1810 }
1811
1812 found:
1813 /* Store comp_dir */
1814 if (lf.found) {
1815 comp_dir = cu_get_comp_dir(&lf.cu_die);
1816 if (comp_dir) {
1817 lr->comp_dir = strdup(comp_dir);
1818 if (!lr->comp_dir)
1819 ret = -ENOMEM;
1820 }
1821 }
1822
1823 pr_debug("path: %s\n", lr->path);
1824 return (ret < 0) ? ret : lf.found;
1825 }
1826
1827 /*
1828 * Find a src file from a DWARF tag path. Prepend optional source path prefix
1829 * and chop off leading directories that do not exist. Result is passed back as
1830 * a newly allocated path on success.
1831 * Return 0 if file was found and readable, -errno otherwise.
1832 */
1833 int get_real_path(const char *raw_path, const char *comp_dir,
1834 char **new_path)
1835 {
1836 const char *prefix = symbol_conf.source_prefix;
1837
1838 if (!prefix) {
1839 if (raw_path[0] != '/' && comp_dir)
1840 /* If not an absolute path, try to use comp_dir */
1841 prefix = comp_dir;
1842 else {
1843 if (access(raw_path, R_OK) == 0) {
1844 *new_path = strdup(raw_path);
1845 return *new_path ? 0 : -ENOMEM;
1846 } else
1847 return -errno;
1848 }
1849 }
1850
1851 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1852 if (!*new_path)
1853 return -ENOMEM;
1854
1855 for (;;) {
1856 sprintf(*new_path, "%s/%s", prefix, raw_path);
1857
1858 if (access(*new_path, R_OK) == 0)
1859 return 0;
1860
1861 if (!symbol_conf.source_prefix) {
1862 /* In case of searching comp_dir, don't retry */
1863 zfree(new_path);
1864 return -errno;
1865 }
1866
1867 switch (errno) {
1868 case ENAMETOOLONG:
1869 case ENOENT:
1870 case EROFS:
1871 case EFAULT:
1872 raw_path = strchr(++raw_path, '/');
1873 if (!raw_path) {
1874 zfree(new_path);
1875 return -ENOENT;
1876 }
1877 continue;
1878
1879 default:
1880 zfree(new_path);
1881 return -errno;
1882 }
1883 }
1884 }
CRIS linux kernel tree