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perf intel-pt: Add lookahead callback
[linux/fpc-iii.git] / tools / perf / util / probe-finder.c
blob6b40cc691a2dc90c3526021b9c0c512c1006b39b
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 "event.h"
23 #include "dso.h"
24 #include "debug.h"
25 #include "intlist.h"
26 #include "util.h"
27 #include "strlist.h"
28 #include "symbol.h"
29 #include "probe-finder.h"
30 #include "probe-file.h"
31 #include "string2.h"
32
33 /* Kprobe tracer basic type is up to u64 */
34 #define MAX_BASIC_TYPE_BITS 64
35
36 /* Dwarf FL wrappers */
37 static char *debuginfo_path; /* Currently dummy */
38
39 static const Dwfl_Callbacks offline_callbacks = {
40 .find_debuginfo = dwfl_standard_find_debuginfo,
41 .debuginfo_path = &debuginfo_path,
42
43 .section_address = dwfl_offline_section_address,
44
45 /* We use this table for core files too. */
46 .find_elf = dwfl_build_id_find_elf,
47 };
48
49 /* Get a Dwarf from offline image */
50 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
51 const char *path)
52 {
53 int fd;
54
55 fd = open(path, O_RDONLY);
56 if (fd < 0)
57 return fd;
58
59 dbg->dwfl = dwfl_begin(&offline_callbacks);
60 if (!dbg->dwfl)
61 goto error;
62
63 dwfl_report_begin(dbg->dwfl);
64 dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
65 if (!dbg->mod)
66 goto error;
67
68 dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
69 if (!dbg->dbg)
70 goto error;
71
72 dwfl_report_end(dbg->dwfl, NULL, NULL);
73
74 return 0;
75 error:
76 if (dbg->dwfl)
77 dwfl_end(dbg->dwfl);
78 else
79 close(fd);
80 memset(dbg, 0, sizeof(*dbg));
81
82 return -ENOENT;
83 }
84
85 static struct debuginfo *__debuginfo__new(const char *path)
86 {
87 struct debuginfo *dbg = zalloc(sizeof(*dbg));
88 if (!dbg)
89 return NULL;
90
91 if (debuginfo__init_offline_dwarf(dbg, path) < 0)
92 zfree(&dbg);
93 if (dbg)
94 pr_debug("Open Debuginfo file: %s\n", path);
95 return dbg;
96 }
97
98 enum dso_binary_type distro_dwarf_types[] = {
99 DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
100 DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
101 DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
102 DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
103 DSO_BINARY_TYPE__NOT_FOUND,
104 };
105
106 struct debuginfo *debuginfo__new(const char *path)
107 {
108 enum dso_binary_type *type;
109 char buf[PATH_MAX], nil = '\0';
110 struct dso *dso;
111 struct debuginfo *dinfo = NULL;
112
113 /* Try to open distro debuginfo files */
114 dso = dso__new(path);
115 if (!dso)
116 goto out;
117
118 for (type = distro_dwarf_types;
119 !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
120 type++) {
121 if (dso__read_binary_type_filename(dso, *type, &nil,
122 buf, PATH_MAX) < 0)
123 continue;
124 dinfo = __debuginfo__new(buf);
125 }
126 dso__put(dso);
127
128 out:
129 /* if failed to open all distro debuginfo, open given binary */
130 return dinfo ? : __debuginfo__new(path);
131 }
132
133 void debuginfo__delete(struct debuginfo *dbg)
134 {
135 if (dbg) {
136 if (dbg->dwfl)
137 dwfl_end(dbg->dwfl);
138 free(dbg);
139 }
140 }
141
142 /*
143 * Probe finder related functions
144 */
145
146 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
147 {
148 struct probe_trace_arg_ref *ref;
149 ref = zalloc(sizeof(struct probe_trace_arg_ref));
150 if (ref != NULL)
151 ref->offset = offs;
152 return ref;
153 }
154
155 /*
156 * Convert a location into trace_arg.
157 * If tvar == NULL, this just checks variable can be converted.
158 * If fentry == true and vr_die is a parameter, do huristic search
159 * for the location fuzzed by function entry mcount.
160 */
161 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
162 Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
163 unsigned int machine,
164 struct probe_trace_arg *tvar)
165 {
166 Dwarf_Attribute attr;
167 Dwarf_Addr tmp = 0;
168 Dwarf_Op *op;
169 size_t nops;
170 unsigned int regn;
171 Dwarf_Word offs = 0;
172 bool ref = false;
173 const char *regs;
174 int ret, ret2 = 0;
175
176 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
177 goto static_var;
178
179 /* TODO: handle more than 1 exprs */
180 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
181 return -EINVAL; /* Broken DIE ? */
182 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
183 ret = dwarf_entrypc(sp_die, &tmp);
184 if (ret)
185 return -ENOENT;
186
187 if (probe_conf.show_location_range &&
188 (dwarf_tag(vr_die) == DW_TAG_variable)) {
189 ret2 = -ERANGE;
190 } else if (addr != tmp ||
191 dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
192 return -ENOENT;
193 }
194
195 ret = dwarf_highpc(sp_die, &tmp);
196 if (ret)
197 return -ENOENT;
198 /*
199 * This is fuzzed by fentry mcount. We try to find the
200 * parameter location at the earliest address.
201 */
202 for (addr += 1; addr <= tmp; addr++) {
203 if (dwarf_getlocation_addr(&attr, addr, &op,
204 &nops, 1) > 0)
205 goto found;
206 }
207 return -ENOENT;
208 }
209 found:
210 if (nops == 0)
211 /* TODO: Support const_value */
212 return -ENOENT;
213
214 if (op->atom == DW_OP_addr) {
215 static_var:
216 if (!tvar)
217 return ret2;
218 /* Static variables on memory (not stack), make @varname */
219 ret = strlen(dwarf_diename(vr_die));
220 tvar->value = zalloc(ret + 2);
221 if (tvar->value == NULL)
222 return -ENOMEM;
223 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
224 tvar->ref = alloc_trace_arg_ref((long)offs);
225 if (tvar->ref == NULL)
226 return -ENOMEM;
227 return ret2;
228 }
229
230 /* If this is based on frame buffer, set the offset */
231 if (op->atom == DW_OP_fbreg) {
232 if (fb_ops == NULL)
233 return -ENOTSUP;
234 ref = true;
235 offs = op->number;
236 op = &fb_ops[0];
237 }
238
239 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
240 regn = op->atom - DW_OP_breg0;
241 offs += op->number;
242 ref = true;
243 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
244 regn = op->atom - DW_OP_reg0;
245 } else if (op->atom == DW_OP_bregx) {
246 regn = op->number;
247 offs += op->number2;
248 ref = true;
249 } else if (op->atom == DW_OP_regx) {
250 regn = op->number;
251 } else {
252 pr_debug("DW_OP %x is not supported.\n", op->atom);
253 return -ENOTSUP;
254 }
255
256 if (!tvar)
257 return ret2;
258
259 regs = get_dwarf_regstr(regn, machine);
260 if (!regs) {
261 /* This should be a bug in DWARF or this tool */
262 pr_warning("Mapping for the register number %u "
263 "missing on this architecture.\n", regn);
264 return -ENOTSUP;
265 }
266
267 tvar->value = strdup(regs);
268 if (tvar->value == NULL)
269 return -ENOMEM;
270
271 if (ref) {
272 tvar->ref = alloc_trace_arg_ref((long)offs);
273 if (tvar->ref == NULL)
274 return -ENOMEM;
275 }
276 return ret2;
277 }
278
279 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
280
281 static int convert_variable_type(Dwarf_Die *vr_die,
282 struct probe_trace_arg *tvar,
283 const char *cast)
284 {
285 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
286 Dwarf_Die type;
287 char buf[16];
288 char sbuf[STRERR_BUFSIZE];
289 int bsize, boffs, total;
290 int ret;
291 char prefix;
292
293 /* TODO: check all types */
294 if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
295 strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
296 /* Non string type is OK */
297 /* and respect signedness/hexadecimal cast */
298 tvar->type = strdup(cast);
299 return (tvar->type == NULL) ? -ENOMEM : 0;
300 }
301
302 bsize = dwarf_bitsize(vr_die);
303 if (bsize > 0) {
304 /* This is a bitfield */
305 boffs = dwarf_bitoffset(vr_die);
306 total = dwarf_bytesize(vr_die);
307 if (boffs < 0 || total < 0)
308 return -ENOENT;
309 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
310 BYTES_TO_BITS(total));
311 goto formatted;
312 }
313
314 if (die_get_real_type(vr_die, &type) == NULL) {
315 pr_warning("Failed to get a type information of %s.\n",
316 dwarf_diename(vr_die));
317 return -ENOENT;
318 }
319
320 pr_debug("%s type is %s.\n",
321 dwarf_diename(vr_die), dwarf_diename(&type));
322
323 if (cast && strcmp(cast, "string") == 0) { /* String type */
324 ret = dwarf_tag(&type);
325 if (ret != DW_TAG_pointer_type &&
326 ret != DW_TAG_array_type) {
327 pr_warning("Failed to cast into string: "
328 "%s(%s) is not a pointer nor array.\n",
329 dwarf_diename(vr_die), dwarf_diename(&type));
330 return -EINVAL;
331 }
332 if (die_get_real_type(&type, &type) == NULL) {
333 pr_warning("Failed to get a type"
334 " information.\n");
335 return -ENOENT;
336 }
337 if (ret == DW_TAG_pointer_type) {
338 while (*ref_ptr)
339 ref_ptr = &(*ref_ptr)->next;
340 /* Add new reference with offset +0 */
341 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
342 if (*ref_ptr == NULL) {
343 pr_warning("Out of memory error\n");
344 return -ENOMEM;
345 }
346 }
347 if (!die_compare_name(&type, "char") &&
348 !die_compare_name(&type, "unsigned char")) {
349 pr_warning("Failed to cast into string: "
350 "%s is not (unsigned) char *.\n",
351 dwarf_diename(vr_die));
352 return -EINVAL;
353 }
354 tvar->type = strdup(cast);
355 return (tvar->type == NULL) ? -ENOMEM : 0;
356 }
357
358 if (cast && (strcmp(cast, "u") == 0))
359 prefix = 'u';
360 else if (cast && (strcmp(cast, "s") == 0))
361 prefix = 's';
362 else if (cast && (strcmp(cast, "x") == 0) &&
363 probe_type_is_available(PROBE_TYPE_X))
364 prefix = 'x';
365 else
366 prefix = die_is_signed_type(&type) ? 's' :
367 probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
368
369 ret = dwarf_bytesize(&type);
370 if (ret <= 0)
371 /* No size ... try to use default type */
372 return 0;
373 ret = BYTES_TO_BITS(ret);
374
375 /* Check the bitwidth */
376 if (ret > MAX_BASIC_TYPE_BITS) {
377 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
378 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
379 ret = MAX_BASIC_TYPE_BITS;
380 }
381 ret = snprintf(buf, 16, "%c%d", prefix, ret);
382
383 formatted:
384 if (ret < 0 || ret >= 16) {
385 if (ret >= 16)
386 ret = -E2BIG;
387 pr_warning("Failed to convert variable type: %s\n",
388 str_error_r(-ret, sbuf, sizeof(sbuf)));
389 return ret;
390 }
391 tvar->type = strdup(buf);
392 if (tvar->type == NULL)
393 return -ENOMEM;
394 return 0;
395 }
396
397 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
398 struct perf_probe_arg_field *field,
399 struct probe_trace_arg_ref **ref_ptr,
400 Dwarf_Die *die_mem)
401 {
402 struct probe_trace_arg_ref *ref = *ref_ptr;
403 Dwarf_Die type;
404 Dwarf_Word offs;
405 int ret, tag;
406
407 pr_debug("converting %s in %s\n", field->name, varname);
408 if (die_get_real_type(vr_die, &type) == NULL) {
409 pr_warning("Failed to get the type of %s.\n", varname);
410 return -ENOENT;
411 }
412 pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type),
413 (unsigned)dwarf_dieoffset(&type));
414 tag = dwarf_tag(&type);
415
416 if (field->name[0] == '[' &&
417 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
418 /* Save original type for next field or type */
419 memcpy(die_mem, &type, sizeof(*die_mem));
420 /* Get the type of this array */
421 if (die_get_real_type(&type, &type) == NULL) {
422 pr_warning("Failed to get the type of %s.\n", varname);
423 return -ENOENT;
424 }
425 pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type),
426 (unsigned)dwarf_dieoffset(&type));
427 if (tag == DW_TAG_pointer_type) {
428 ref = zalloc(sizeof(struct probe_trace_arg_ref));
429 if (ref == NULL)
430 return -ENOMEM;
431 if (*ref_ptr)
432 (*ref_ptr)->next = ref;
433 else
434 *ref_ptr = ref;
435 }
436 ref->offset += dwarf_bytesize(&type) * field->index;
437 goto next;
438 } else if (tag == DW_TAG_pointer_type) {
439 /* Check the pointer and dereference */
440 if (!field->ref) {
441 pr_err("Semantic error: %s must be referred by '->'\n",
442 field->name);
443 return -EINVAL;
444 }
445 /* Get the type pointed by this pointer */
446 if (die_get_real_type(&type, &type) == NULL) {
447 pr_warning("Failed to get the type of %s.\n", varname);
448 return -ENOENT;
449 }
450 /* Verify it is a data structure */
451 tag = dwarf_tag(&type);
452 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
453 pr_warning("%s is not a data structure nor a union.\n",
454 varname);
455 return -EINVAL;
456 }
457
458 ref = zalloc(sizeof(struct probe_trace_arg_ref));
459 if (ref == NULL)
460 return -ENOMEM;
461 if (*ref_ptr)
462 (*ref_ptr)->next = ref;
463 else
464 *ref_ptr = ref;
465 } else {
466 /* Verify it is a data structure */
467 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
468 pr_warning("%s is not a data structure nor a union.\n",
469 varname);
470 return -EINVAL;
471 }
472 if (field->name[0] == '[') {
473 pr_err("Semantic error: %s is not a pointer"
474 " nor array.\n", varname);
475 return -EINVAL;
476 }
477 /* While prcessing unnamed field, we don't care about this */
478 if (field->ref && dwarf_diename(vr_die)) {
479 pr_err("Semantic error: %s must be referred by '.'\n",
480 field->name);
481 return -EINVAL;
482 }
483 if (!ref) {
484 pr_warning("Structure on a register is not "
485 "supported yet.\n");
486 return -ENOTSUP;
487 }
488 }
489
490 if (die_find_member(&type, field->name, die_mem) == NULL) {
491 pr_warning("%s(type:%s) has no member %s.\n", varname,
492 dwarf_diename(&type), field->name);
493 return -EINVAL;
494 }
495
496 /* Get the offset of the field */
497 if (tag == DW_TAG_union_type) {
498 offs = 0;
499 } else {
500 ret = die_get_data_member_location(die_mem, &offs);
501 if (ret < 0) {
502 pr_warning("Failed to get the offset of %s.\n",
503 field->name);
504 return ret;
505 }
506 }
507 ref->offset += (long)offs;
508
509 /* If this member is unnamed, we need to reuse this field */
510 if (!dwarf_diename(die_mem))
511 return convert_variable_fields(die_mem, varname, field,
512 &ref, die_mem);
513
514 next:
515 /* Converting next field */
516 if (field->next)
517 return convert_variable_fields(die_mem, field->name,
518 field->next, &ref, die_mem);
519 else
520 return 0;
521 }
522
523 /* Show a variables in kprobe event format */
524 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
525 {
526 Dwarf_Die die_mem;
527 int ret;
528
529 pr_debug("Converting variable %s into trace event.\n",
530 dwarf_diename(vr_die));
531
532 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
533 &pf->sp_die, pf->machine, pf->tvar);
534 if (ret == -ENOENT || ret == -EINVAL) {
535 pr_err("Failed to find the location of the '%s' variable at this address.\n"
536 " Perhaps it has been optimized out.\n"
537 " Use -V with the --range option to show '%s' location range.\n",
538 pf->pvar->var, pf->pvar->var);
539 } else if (ret == -ENOTSUP)
540 pr_err("Sorry, we don't support this variable location yet.\n");
541 else if (ret == 0 && pf->pvar->field) {
542 ret = convert_variable_fields(vr_die, pf->pvar->var,
543 pf->pvar->field, &pf->tvar->ref,
544 &die_mem);
545 vr_die = &die_mem;
546 }
547 if (ret == 0)
548 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
549 /* *expr will be cached in libdw. Don't free it. */
550 return ret;
551 }
552
553 /* Find a variable in a scope DIE */
554 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
555 {
556 Dwarf_Die vr_die;
557 char *buf, *ptr;
558 int ret = 0;
559
560 /* Copy raw parameters */
561 if (!is_c_varname(pf->pvar->var))
562 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
563
564 if (pf->pvar->name)
565 pf->tvar->name = strdup(pf->pvar->name);
566 else {
567 buf = synthesize_perf_probe_arg(pf->pvar);
568 if (!buf)
569 return -ENOMEM;
570 ptr = strchr(buf, ':'); /* Change type separator to _ */
571 if (ptr)
572 *ptr = '_';
573 pf->tvar->name = buf;
574 }
575 if (pf->tvar->name == NULL)
576 return -ENOMEM;
577
578 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
579 /* Search child die for local variables and parameters. */
580 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
581 /* Search again in global variables */
582 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
583 0, &vr_die)) {
584 pr_warning("Failed to find '%s' in this function.\n",
585 pf->pvar->var);
586 ret = -ENOENT;
587 }
588 }
589 if (ret >= 0)
590 ret = convert_variable(&vr_die, pf);
591
592 return ret;
593 }
594
595 /* Convert subprogram DIE to trace point */
596 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
597 Dwarf_Addr paddr, bool retprobe,
598 const char *function,
599 struct probe_trace_point *tp)
600 {
601 Dwarf_Addr eaddr, highaddr;
602 GElf_Sym sym;
603 const char *symbol;
604
605 /* Verify the address is correct */
606 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
607 pr_warning("Failed to get entry address of %s\n",
608 dwarf_diename(sp_die));
609 return -ENOENT;
610 }
611 if (dwarf_highpc(sp_die, &highaddr) != 0) {
612 pr_warning("Failed to get end address of %s\n",
613 dwarf_diename(sp_die));
614 return -ENOENT;
615 }
616 if (paddr > highaddr) {
617 pr_warning("Offset specified is greater than size of %s\n",
618 dwarf_diename(sp_die));
619 return -EINVAL;
620 }
621
622 symbol = dwarf_diename(sp_die);
623 if (!symbol) {
624 /* Try to get the symbol name from symtab */
625 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
626 if (!symbol) {
627 pr_warning("Failed to find symbol at 0x%lx\n",
628 (unsigned long)paddr);
629 return -ENOENT;
630 }
631 eaddr = sym.st_value;
632 }
633 tp->offset = (unsigned long)(paddr - eaddr);
634 tp->address = (unsigned long)paddr;
635 tp->symbol = strdup(symbol);
636 if (!tp->symbol)
637 return -ENOMEM;
638
639 /* Return probe must be on the head of a subprogram */
640 if (retprobe) {
641 if (eaddr != paddr) {
642 pr_warning("Failed to find \"%s%%return\",\n"
643 " because %s is an inlined function and"
644 " has no return point.\n", function,
645 function);
646 return -EINVAL;
647 }
648 tp->retprobe = true;
649 }
650
651 return 0;
652 }
653
654 /* Call probe_finder callback with scope DIE */
655 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
656 {
657 Dwarf_Attribute fb_attr;
658 Dwarf_Frame *frame = NULL;
659 size_t nops;
660 int ret;
661
662 if (!sc_die) {
663 pr_err("Caller must pass a scope DIE. Program error.\n");
664 return -EINVAL;
665 }
666
667 /* If not a real subprogram, find a real one */
668 if (!die_is_func_def(sc_die)) {
669 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
670 if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
671 pr_warning("Ignoring tail call from %s\n",
672 dwarf_diename(&pf->sp_die));
673 return 0;
674 } else {
675 pr_warning("Failed to find probe point in any "
676 "functions.\n");
677 return -ENOENT;
678 }
679 }
680 } else
681 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
682
683 /* Get the frame base attribute/ops from subprogram */
684 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
685 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
686 if (ret <= 0 || nops == 0) {
687 pf->fb_ops = NULL;
688 #if _ELFUTILS_PREREQ(0, 142)
689 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
690 (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
691 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
692 (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
693 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
694 pr_warning("Failed to get call frame on 0x%jx\n",
695 (uintmax_t)pf->addr);
696 free(frame);
697 return -ENOENT;
698 }
699 #endif
700 }
701
702 /* Call finder's callback handler */
703 ret = pf->callback(sc_die, pf);
704
705 /* Since *pf->fb_ops can be a part of frame. we should free it here. */
706 free(frame);
707 pf->fb_ops = NULL;
708
709 return ret;
710 }
711
712 struct find_scope_param {
713 const char *function;
714 const char *file;
715 int line;
716 int diff;
717 Dwarf_Die *die_mem;
718 bool found;
719 };
720
721 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
722 {
723 struct find_scope_param *fsp = data;
724 const char *file;
725 int lno;
726
727 /* Skip if declared file name does not match */
728 if (fsp->file) {
729 file = dwarf_decl_file(fn_die);
730 if (!file || strcmp(fsp->file, file) != 0)
731 return 0;
732 }
733 /* If the function name is given, that's what user expects */
734 if (fsp->function) {
735 if (die_match_name(fn_die, fsp->function)) {
736 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
737 fsp->found = true;
738 return 1;
739 }
740 } else {
741 /* With the line number, find the nearest declared DIE */
742 dwarf_decl_line(fn_die, &lno);
743 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
744 /* Keep a candidate and continue */
745 fsp->diff = fsp->line - lno;
746 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
747 fsp->found = true;
748 }
749 }
750 return 0;
751 }
752
753 /* Find an appropriate scope fits to given conditions */
754 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
755 {
756 struct find_scope_param fsp = {
757 .function = pf->pev->point.function,
758 .file = pf->fname,
759 .line = pf->lno,
760 .diff = INT_MAX,
761 .die_mem = die_mem,
762 .found = false,
763 };
764
765 cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
766
767 return fsp.found ? die_mem : NULL;
768 }
769
770 static int probe_point_line_walker(const char *fname, int lineno,
771 Dwarf_Addr addr, void *data)
772 {
773 struct probe_finder *pf = data;
774 Dwarf_Die *sc_die, die_mem;
775 int ret;
776
777 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
778 return 0;
779
780 pf->addr = addr;
781 sc_die = find_best_scope(pf, &die_mem);
782 if (!sc_die) {
783 pr_warning("Failed to find scope of probe point.\n");
784 return -ENOENT;
785 }
786
787 ret = call_probe_finder(sc_die, pf);
788
789 /* Continue if no error, because the line will be in inline function */
790 return ret < 0 ? ret : 0;
791 }
792
793 /* Find probe point from its line number */
794 static int find_probe_point_by_line(struct probe_finder *pf)
795 {
796 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
797 }
798
799 /* Find lines which match lazy pattern */
800 static int find_lazy_match_lines(struct intlist *list,
801 const char *fname, const char *pat)
802 {
803 FILE *fp;
804 char *line = NULL;
805 size_t line_len;
806 ssize_t len;
807 int count = 0, linenum = 1;
808 char sbuf[STRERR_BUFSIZE];
809
810 fp = fopen(fname, "r");
811 if (!fp) {
812 pr_warning("Failed to open %s: %s\n", fname,
813 str_error_r(errno, sbuf, sizeof(sbuf)));
814 return -errno;
815 }
816
817 while ((len = getline(&line, &line_len, fp)) > 0) {
818
819 if (line[len - 1] == '\n')
820 line[len - 1] = '\0';
821
822 if (strlazymatch(line, pat)) {
823 intlist__add(list, linenum);
824 count++;
825 }
826 linenum++;
827 }
828
829 if (ferror(fp))
830 count = -errno;
831 free(line);
832 fclose(fp);
833
834 if (count == 0)
835 pr_debug("No matched lines found in %s.\n", fname);
836 return count;
837 }
838
839 static int probe_point_lazy_walker(const char *fname, int lineno,
840 Dwarf_Addr addr, void *data)
841 {
842 struct probe_finder *pf = data;
843 Dwarf_Die *sc_die, die_mem;
844 int ret;
845
846 if (!intlist__has_entry(pf->lcache, lineno) ||
847 strtailcmp(fname, pf->fname) != 0)
848 return 0;
849
850 pr_debug("Probe line found: line:%d addr:0x%llx\n",
851 lineno, (unsigned long long)addr);
852 pf->addr = addr;
853 pf->lno = lineno;
854 sc_die = find_best_scope(pf, &die_mem);
855 if (!sc_die) {
856 pr_warning("Failed to find scope of probe point.\n");
857 return -ENOENT;
858 }
859
860 ret = call_probe_finder(sc_die, pf);
861
862 /*
863 * Continue if no error, because the lazy pattern will match
864 * to other lines
865 */
866 return ret < 0 ? ret : 0;
867 }
868
869 /* Find probe points from lazy pattern */
870 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
871 {
872 int ret = 0;
873 char *fpath;
874
875 if (intlist__empty(pf->lcache)) {
876 const char *comp_dir;
877
878 comp_dir = cu_get_comp_dir(&pf->cu_die);
879 ret = get_real_path(pf->fname, comp_dir, &fpath);
880 if (ret < 0) {
881 pr_warning("Failed to find source file path.\n");
882 return ret;
883 }
884
885 /* Matching lazy line pattern */
886 ret = find_lazy_match_lines(pf->lcache, fpath,
887 pf->pev->point.lazy_line);
888 free(fpath);
889 if (ret <= 0)
890 return ret;
891 }
892
893 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
894 }
895
896 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
897 {
898 struct perf_probe_point *pp = &pf->pev->point;
899
900 /* Not uprobe? */
901 if (!pf->pev->uprobes)
902 return;
903
904 /* Compiled with optimization? */
905 if (die_is_optimized_target(&pf->cu_die))
906 return;
907
908 /* Don't know entrypc? */
909 if (!pf->addr)
910 return;
911
912 /* Only FUNC and FUNC@SRC are eligible. */
913 if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
914 pp->offset || pp->abs_address)
915 return;
916
917 /* Not interested in func parameter? */
918 if (!perf_probe_with_var(pf->pev))
919 return;
920
921 pr_info("Target program is compiled without optimization. Skipping prologue.\n"
922 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
923 pf->addr);
924
925 die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
926 }
927
928 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
929 {
930 struct probe_finder *pf = data;
931 struct perf_probe_point *pp = &pf->pev->point;
932 Dwarf_Addr addr;
933 int ret;
934
935 if (pp->lazy_line)
936 ret = find_probe_point_lazy(in_die, pf);
937 else {
938 /* Get probe address */
939 if (dwarf_entrypc(in_die, &addr) != 0) {
940 pr_warning("Failed to get entry address of %s.\n",
941 dwarf_diename(in_die));
942 return -ENOENT;
943 }
944 if (addr == 0) {
945 pr_debug("%s has no valid entry address. skipped.\n",
946 dwarf_diename(in_die));
947 return -ENOENT;
948 }
949 pf->addr = addr;
950 pf->addr += pp->offset;
951 pr_debug("found inline addr: 0x%jx\n",
952 (uintmax_t)pf->addr);
953
954 ret = call_probe_finder(in_die, pf);
955 }
956
957 return ret;
958 }
959
960 /* Callback parameter with return value for libdw */
961 struct dwarf_callback_param {
962 void *data;
963 int retval;
964 };
965
966 /* Search function from function name */
967 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
968 {
969 struct dwarf_callback_param *param = data;
970 struct probe_finder *pf = param->data;
971 struct perf_probe_point *pp = &pf->pev->point;
972
973 /* Check tag and diename */
974 if (!die_is_func_def(sp_die) ||
975 !die_match_name(sp_die, pp->function))
976 return DWARF_CB_OK;
977
978 /* Check declared file */
979 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
980 return DWARF_CB_OK;
981
982 pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
983 (unsigned long)dwarf_dieoffset(sp_die));
984 pf->fname = dwarf_decl_file(sp_die);
985 if (pp->line) { /* Function relative line */
986 dwarf_decl_line(sp_die, &pf->lno);
987 pf->lno += pp->line;
988 param->retval = find_probe_point_by_line(pf);
989 } else if (die_is_func_instance(sp_die)) {
990 /* Instances always have the entry address */
991 dwarf_entrypc(sp_die, &pf->addr);
992 /* But in some case the entry address is 0 */
993 if (pf->addr == 0) {
994 pr_debug("%s has no entry PC. Skipped\n",
995 dwarf_diename(sp_die));
996 param->retval = 0;
997 /* Real function */
998 } else if (pp->lazy_line)
999 param->retval = find_probe_point_lazy(sp_die, pf);
1000 else {
1001 skip_prologue(sp_die, pf);
1002 pf->addr += pp->offset;
1003 /* TODO: Check the address in this function */
1004 param->retval = call_probe_finder(sp_die, pf);
1005 }
1006 } else if (!probe_conf.no_inlines) {
1007 /* Inlined function: search instances */
1008 param->retval = die_walk_instances(sp_die,
1009 probe_point_inline_cb, (void *)pf);
1010 /* This could be a non-existed inline definition */
1011 if (param->retval == -ENOENT)
1012 param->retval = 0;
1013 }
1014
1015 /* We need to find other candidates */
1016 if (strisglob(pp->function) && param->retval >= 0) {
1017 param->retval = 0; /* We have to clear the result */
1018 return DWARF_CB_OK;
1019 }
1020
1021 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1022 }
1023
1024 static int find_probe_point_by_func(struct probe_finder *pf)
1025 {
1026 struct dwarf_callback_param _param = {.data = (void *)pf,
1027 .retval = 0};
1028 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1029 return _param.retval;
1030 }
1031
1032 struct pubname_callback_param {
1033 char *function;
1034 char *file;
1035 Dwarf_Die *cu_die;
1036 Dwarf_Die *sp_die;
1037 int found;
1038 };
1039
1040 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1041 {
1042 struct pubname_callback_param *param = data;
1043
1044 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1045 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1046 return DWARF_CB_OK;
1047
1048 if (die_match_name(param->sp_die, param->function)) {
1049 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1050 return DWARF_CB_OK;
1051
1052 if (param->file &&
1053 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1054 return DWARF_CB_OK;
1055
1056 param->found = 1;
1057 return DWARF_CB_ABORT;
1058 }
1059 }
1060
1061 return DWARF_CB_OK;
1062 }
1063
1064 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1065 struct probe_finder *pf)
1066 {
1067 struct perf_probe_point *pp = &pf->pev->point;
1068 Dwarf_Off off, noff;
1069 size_t cuhl;
1070 Dwarf_Die *diep;
1071 int ret = 0;
1072
1073 off = 0;
1074 pf->lcache = intlist__new(NULL);
1075 if (!pf->lcache)
1076 return -ENOMEM;
1077
1078 /* Fastpath: lookup by function name from .debug_pubnames section */
1079 if (pp->function && !strisglob(pp->function)) {
1080 struct pubname_callback_param pubname_param = {
1081 .function = pp->function,
1082 .file = pp->file,
1083 .cu_die = &pf->cu_die,
1084 .sp_die = &pf->sp_die,
1085 .found = 0,
1086 };
1087 struct dwarf_callback_param probe_param = {
1088 .data = pf,
1089 };
1090
1091 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1092 &pubname_param, 0);
1093 if (pubname_param.found) {
1094 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1095 if (ret)
1096 goto found;
1097 }
1098 }
1099
1100 /* Loop on CUs (Compilation Unit) */
1101 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1102 /* Get the DIE(Debugging Information Entry) of this CU */
1103 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1104 if (!diep)
1105 continue;
1106
1107 /* Check if target file is included. */
1108 if (pp->file)
1109 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1110 else
1111 pf->fname = NULL;
1112
1113 if (!pp->file || pf->fname) {
1114 if (pp->function)
1115 ret = find_probe_point_by_func(pf);
1116 else if (pp->lazy_line)
1117 ret = find_probe_point_lazy(&pf->cu_die, pf);
1118 else {
1119 pf->lno = pp->line;
1120 ret = find_probe_point_by_line(pf);
1121 }
1122 if (ret < 0)
1123 break;
1124 }
1125 off = noff;
1126 }
1127
1128 found:
1129 intlist__delete(pf->lcache);
1130 pf->lcache = NULL;
1131
1132 return ret;
1133 }
1134
1135 /* Find probe points from debuginfo */
1136 static int debuginfo__find_probes(struct debuginfo *dbg,
1137 struct probe_finder *pf)
1138 {
1139 int ret = 0;
1140 Elf *elf;
1141 GElf_Ehdr ehdr;
1142
1143 if (pf->cfi_eh || pf->cfi_dbg)
1144 return debuginfo__find_probe_location(dbg, pf);
1145
1146 /* Get the call frame information from this dwarf */
1147 elf = dwarf_getelf(dbg->dbg);
1148 if (elf == NULL)
1149 return -EINVAL;
1150
1151 if (gelf_getehdr(elf, &ehdr) == NULL)
1152 return -EINVAL;
1153
1154 pf->machine = ehdr.e_machine;
1155
1156 #if _ELFUTILS_PREREQ(0, 142)
1157 do {
1158 GElf_Shdr shdr;
1159
1160 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1161 shdr.sh_type == SHT_PROGBITS)
1162 pf->cfi_eh = dwarf_getcfi_elf(elf);
1163
1164 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1165 } while (0);
1166 #endif
1167
1168 ret = debuginfo__find_probe_location(dbg, pf);
1169 return ret;
1170 }
1171
1172 struct local_vars_finder {
1173 struct probe_finder *pf;
1174 struct perf_probe_arg *args;
1175 bool vars;
1176 int max_args;
1177 int nargs;
1178 int ret;
1179 };
1180
1181 /* Collect available variables in this scope */
1182 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1183 {
1184 struct local_vars_finder *vf = data;
1185 struct probe_finder *pf = vf->pf;
1186 int tag;
1187
1188 tag = dwarf_tag(die_mem);
1189 if (tag == DW_TAG_formal_parameter ||
1190 (tag == DW_TAG_variable && vf->vars)) {
1191 if (convert_variable_location(die_mem, vf->pf->addr,
1192 vf->pf->fb_ops, &pf->sp_die,
1193 pf->machine, NULL) == 0) {
1194 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1195 if (vf->args[vf->nargs].var == NULL) {
1196 vf->ret = -ENOMEM;
1197 return DIE_FIND_CB_END;
1198 }
1199 pr_debug(" %s", vf->args[vf->nargs].var);
1200 vf->nargs++;
1201 }
1202 }
1203
1204 if (dwarf_haspc(die_mem, vf->pf->addr))
1205 return DIE_FIND_CB_CONTINUE;
1206 else
1207 return DIE_FIND_CB_SIBLING;
1208 }
1209
1210 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1211 struct perf_probe_arg *args)
1212 {
1213 Dwarf_Die die_mem;
1214 int i;
1215 int n = 0;
1216 struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1217 .max_args = MAX_PROBE_ARGS, .ret = 0};
1218
1219 for (i = 0; i < pf->pev->nargs; i++) {
1220 /* var never be NULL */
1221 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1222 vf.vars = true;
1223 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1224 /* Copy normal argument */
1225 args[n] = pf->pev->args[i];
1226 n++;
1227 continue;
1228 }
1229 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1230 vf.nargs = n;
1231 /* Special local variables */
1232 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1233 &die_mem);
1234 pr_debug(" (%d)\n", vf.nargs - n);
1235 if (vf.ret < 0)
1236 return vf.ret;
1237 n = vf.nargs;
1238 }
1239 return n;
1240 }
1241
1242 /* Add a found probe point into trace event list */
1243 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1244 {
1245 struct trace_event_finder *tf =
1246 container_of(pf, struct trace_event_finder, pf);
1247 struct perf_probe_point *pp = &pf->pev->point;
1248 struct probe_trace_event *tev;
1249 struct perf_probe_arg *args = NULL;
1250 int ret, i;
1251
1252 /* Check number of tevs */
1253 if (tf->ntevs == tf->max_tevs) {
1254 pr_warning("Too many( > %d) probe point found.\n",
1255 tf->max_tevs);
1256 return -ERANGE;
1257 }
1258 tev = &tf->tevs[tf->ntevs++];
1259
1260 /* Trace point should be converted from subprogram DIE */
1261 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1262 pp->retprobe, pp->function, &tev->point);
1263 if (ret < 0)
1264 goto end;
1265
1266 tev->point.realname = strdup(dwarf_diename(sc_die));
1267 if (!tev->point.realname) {
1268 ret = -ENOMEM;
1269 goto end;
1270 }
1271
1272 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1273 tev->point.offset);
1274
1275 /* Expand special probe argument if exist */
1276 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1277 if (args == NULL) {
1278 ret = -ENOMEM;
1279 goto end;
1280 }
1281
1282 ret = expand_probe_args(sc_die, pf, args);
1283 if (ret < 0)
1284 goto end;
1285
1286 tev->nargs = ret;
1287 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1288 if (tev->args == NULL) {
1289 ret = -ENOMEM;
1290 goto end;
1291 }
1292
1293 /* Find each argument */
1294 for (i = 0; i < tev->nargs; i++) {
1295 pf->pvar = &args[i];
1296 pf->tvar = &tev->args[i];
1297 /* Variable should be found from scope DIE */
1298 ret = find_variable(sc_die, pf);
1299 if (ret != 0)
1300 break;
1301 }
1302
1303 end:
1304 if (ret) {
1305 clear_probe_trace_event(tev);
1306 tf->ntevs--;
1307 }
1308 free(args);
1309 return ret;
1310 }
1311
1312 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1313 int debuginfo__find_trace_events(struct debuginfo *dbg,
1314 struct perf_probe_event *pev,
1315 struct probe_trace_event **tevs)
1316 {
1317 struct trace_event_finder tf = {
1318 .pf = {.pev = pev, .callback = add_probe_trace_event},
1319 .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1320 int ret, i;
1321
1322 /* Allocate result tevs array */
1323 *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1324 if (*tevs == NULL)
1325 return -ENOMEM;
1326
1327 tf.tevs = *tevs;
1328 tf.ntevs = 0;
1329
1330 ret = debuginfo__find_probes(dbg, &tf.pf);
1331 if (ret < 0) {
1332 for (i = 0; i < tf.ntevs; i++)
1333 clear_probe_trace_event(&tf.tevs[i]);
1334 zfree(tevs);
1335 return ret;
1336 }
1337
1338 return (ret < 0) ? ret : tf.ntevs;
1339 }
1340
1341 /* Collect available variables in this scope */
1342 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1343 {
1344 struct available_var_finder *af = data;
1345 struct variable_list *vl;
1346 struct strbuf buf = STRBUF_INIT;
1347 int tag, ret;
1348
1349 vl = &af->vls[af->nvls - 1];
1350
1351 tag = dwarf_tag(die_mem);
1352 if (tag == DW_TAG_formal_parameter ||
1353 tag == DW_TAG_variable) {
1354 ret = convert_variable_location(die_mem, af->pf.addr,
1355 af->pf.fb_ops, &af->pf.sp_die,
1356 af->pf.machine, NULL);
1357 if (ret == 0 || ret == -ERANGE) {
1358 int ret2;
1359 bool externs = !af->child;
1360
1361 if (strbuf_init(&buf, 64) < 0)
1362 goto error;
1363
1364 if (probe_conf.show_location_range) {
1365 if (!externs)
1366 ret2 = strbuf_add(&buf,
1367 ret ? "[INV]\t" : "[VAL]\t", 6);
1368 else
1369 ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1370 if (ret2)
1371 goto error;
1372 }
1373
1374 ret2 = die_get_varname(die_mem, &buf);
1375
1376 if (!ret2 && probe_conf.show_location_range &&
1377 !externs) {
1378 if (strbuf_addch(&buf, '\t') < 0)
1379 goto error;
1380 ret2 = die_get_var_range(&af->pf.sp_die,
1381 die_mem, &buf);
1382 }
1383
1384 pr_debug("Add new var: %s\n", buf.buf);
1385 if (ret2 == 0) {
1386 strlist__add(vl->vars,
1387 strbuf_detach(&buf, NULL));
1388 }
1389 strbuf_release(&buf);
1390 }
1391 }
1392
1393 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1394 return DIE_FIND_CB_CONTINUE;
1395 else
1396 return DIE_FIND_CB_SIBLING;
1397 error:
1398 strbuf_release(&buf);
1399 pr_debug("Error in strbuf\n");
1400 return DIE_FIND_CB_END;
1401 }
1402
1403 /* Add a found vars into available variables list */
1404 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1405 {
1406 struct available_var_finder *af =
1407 container_of(pf, struct available_var_finder, pf);
1408 struct perf_probe_point *pp = &pf->pev->point;
1409 struct variable_list *vl;
1410 Dwarf_Die die_mem;
1411 int ret;
1412
1413 /* Check number of tevs */
1414 if (af->nvls == af->max_vls) {
1415 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1416 return -ERANGE;
1417 }
1418 vl = &af->vls[af->nvls++];
1419
1420 /* Trace point should be converted from subprogram DIE */
1421 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1422 pp->retprobe, pp->function, &vl->point);
1423 if (ret < 0)
1424 return ret;
1425
1426 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1427 vl->point.offset);
1428
1429 /* Find local variables */
1430 vl->vars = strlist__new(NULL, NULL);
1431 if (vl->vars == NULL)
1432 return -ENOMEM;
1433 af->child = true;
1434 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1435
1436 /* Find external variables */
1437 if (!probe_conf.show_ext_vars)
1438 goto out;
1439 /* Don't need to search child DIE for external vars. */
1440 af->child = false;
1441 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1442
1443 out:
1444 if (strlist__empty(vl->vars)) {
1445 strlist__delete(vl->vars);
1446 vl->vars = NULL;
1447 }
1448
1449 return ret;
1450 }
1451
1452 /*
1453 * Find available variables at given probe point
1454 * Return the number of found probe points. Return 0 if there is no
1455 * matched probe point. Return <0 if an error occurs.
1456 */
1457 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1458 struct perf_probe_event *pev,
1459 struct variable_list **vls)
1460 {
1461 struct available_var_finder af = {
1462 .pf = {.pev = pev, .callback = add_available_vars},
1463 .mod = dbg->mod,
1464 .max_vls = probe_conf.max_probes};
1465 int ret;
1466
1467 /* Allocate result vls array */
1468 *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1469 if (*vls == NULL)
1470 return -ENOMEM;
1471
1472 af.vls = *vls;
1473 af.nvls = 0;
1474
1475 ret = debuginfo__find_probes(dbg, &af.pf);
1476 if (ret < 0) {
1477 /* Free vlist for error */
1478 while (af.nvls--) {
1479 zfree(&af.vls[af.nvls].point.symbol);
1480 strlist__delete(af.vls[af.nvls].vars);
1481 }
1482 zfree(vls);
1483 return ret;
1484 }
1485
1486 return (ret < 0) ? ret : af.nvls;
1487 }
1488
1489 /* For the kernel module, we need a special code to get a DIE */
1490 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1491 bool adjust_offset)
1492 {
1493 int n, i;
1494 Elf32_Word shndx;
1495 Elf_Scn *scn;
1496 Elf *elf;
1497 GElf_Shdr mem, *shdr;
1498 const char *p;
1499
1500 elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1501 if (!elf)
1502 return -EINVAL;
1503
1504 /* Get the number of relocations */
1505 n = dwfl_module_relocations(dbg->mod);
1506 if (n < 0)
1507 return -ENOENT;
1508 /* Search the relocation related .text section */
1509 for (i = 0; i < n; i++) {
1510 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1511 if (strcmp(p, ".text") == 0) {
1512 /* OK, get the section header */
1513 scn = elf_getscn(elf, shndx);
1514 if (!scn)
1515 return -ENOENT;
1516 shdr = gelf_getshdr(scn, &mem);
1517 if (!shdr)
1518 return -ENOENT;
1519 *offs = shdr->sh_addr;
1520 if (adjust_offset)
1521 *offs -= shdr->sh_offset;
1522 }
1523 }
1524 return 0;
1525 }
1526
1527 /* Reverse search */
1528 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1529 struct perf_probe_point *ppt)
1530 {
1531 Dwarf_Die cudie, spdie, indie;
1532 Dwarf_Addr _addr = 0, baseaddr = 0;
1533 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1534 int baseline = 0, lineno = 0, ret = 0;
1535
1536 /* We always need to relocate the address for aranges */
1537 if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1538 addr += baseaddr;
1539 /* Find cu die */
1540 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1541 pr_warning("Failed to find debug information for address %lx\n",
1542 addr);
1543 ret = -EINVAL;
1544 goto end;
1545 }
1546
1547 /* Find a corresponding line (filename and lineno) */
1548 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1549 /* Don't care whether it failed or not */
1550
1551 /* Find a corresponding function (name, baseline and baseaddr) */
1552 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1553 /* Get function entry information */
1554 func = basefunc = dwarf_diename(&spdie);
1555 if (!func ||
1556 dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1557 dwarf_decl_line(&spdie, &baseline) != 0) {
1558 lineno = 0;
1559 goto post;
1560 }
1561
1562 fname = dwarf_decl_file(&spdie);
1563 if (addr == (unsigned long)baseaddr) {
1564 /* Function entry - Relative line number is 0 */
1565 lineno = baseline;
1566 goto post;
1567 }
1568
1569 /* Track down the inline functions step by step */
1570 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1571 &indie)) {
1572 /* There is an inline function */
1573 if (dwarf_entrypc(&indie, &_addr) == 0 &&
1574 _addr == addr) {
1575 /*
1576 * addr is at an inline function entry.
1577 * In this case, lineno should be the call-site
1578 * line number. (overwrite lineinfo)
1579 */
1580 lineno = die_get_call_lineno(&indie);
1581 fname = die_get_call_file(&indie);
1582 break;
1583 } else {
1584 /*
1585 * addr is in an inline function body.
1586 * Since lineno points one of the lines
1587 * of the inline function, baseline should
1588 * be the entry line of the inline function.
1589 */
1590 tmp = dwarf_diename(&indie);
1591 if (!tmp ||
1592 dwarf_decl_line(&indie, &baseline) != 0)
1593 break;
1594 func = tmp;
1595 spdie = indie;
1596 }
1597 }
1598 /* Verify the lineno and baseline are in a same file */
1599 tmp = dwarf_decl_file(&spdie);
1600 if (!tmp || strcmp(tmp, fname) != 0)
1601 lineno = 0;
1602 }
1603
1604 post:
1605 /* Make a relative line number or an offset */
1606 if (lineno)
1607 ppt->line = lineno - baseline;
1608 else if (basefunc) {
1609 ppt->offset = addr - (unsigned long)baseaddr;
1610 func = basefunc;
1611 }
1612
1613 /* Duplicate strings */
1614 if (func) {
1615 ppt->function = strdup(func);
1616 if (ppt->function == NULL) {
1617 ret = -ENOMEM;
1618 goto end;
1619 }
1620 }
1621 if (fname) {
1622 ppt->file = strdup(fname);
1623 if (ppt->file == NULL) {
1624 zfree(&ppt->function);
1625 ret = -ENOMEM;
1626 goto end;
1627 }
1628 }
1629 end:
1630 if (ret == 0 && (fname || func))
1631 ret = 1; /* Found a point */
1632 return ret;
1633 }
1634
1635 /* Add a line and store the src path */
1636 static int line_range_add_line(const char *src, unsigned int lineno,
1637 struct line_range *lr)
1638 {
1639 /* Copy source path */
1640 if (!lr->path) {
1641 lr->path = strdup(src);
1642 if (lr->path == NULL)
1643 return -ENOMEM;
1644 }
1645 return intlist__add(lr->line_list, lineno);
1646 }
1647
1648 static int line_range_walk_cb(const char *fname, int lineno,
1649 Dwarf_Addr addr __maybe_unused,
1650 void *data)
1651 {
1652 struct line_finder *lf = data;
1653 int err;
1654
1655 if ((strtailcmp(fname, lf->fname) != 0) ||
1656 (lf->lno_s > lineno || lf->lno_e < lineno))
1657 return 0;
1658
1659 err = line_range_add_line(fname, lineno, lf->lr);
1660 if (err < 0 && err != -EEXIST)
1661 return err;
1662
1663 return 0;
1664 }
1665
1666 /* Find line range from its line number */
1667 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1668 {
1669 int ret;
1670
1671 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1672
1673 /* Update status */
1674 if (ret >= 0)
1675 if (!intlist__empty(lf->lr->line_list))
1676 ret = lf->found = 1;
1677 else
1678 ret = 0; /* Lines are not found */
1679 else {
1680 zfree(&lf->lr->path);
1681 }
1682 return ret;
1683 }
1684
1685 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1686 {
1687 int ret = find_line_range_by_line(in_die, data);
1688
1689 /*
1690 * We have to check all instances of inlined function, because
1691 * some execution paths can be optimized out depends on the
1692 * function argument of instances. However, if an error occurs,
1693 * it should be handled by the caller.
1694 */
1695 return ret < 0 ? ret : 0;
1696 }
1697
1698 /* Search function definition from function name */
1699 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1700 {
1701 struct dwarf_callback_param *param = data;
1702 struct line_finder *lf = param->data;
1703 struct line_range *lr = lf->lr;
1704
1705 /* Check declared file */
1706 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1707 return DWARF_CB_OK;
1708
1709 if (die_is_func_def(sp_die) &&
1710 die_match_name(sp_die, lr->function)) {
1711 lf->fname = dwarf_decl_file(sp_die);
1712 dwarf_decl_line(sp_die, &lr->offset);
1713 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1714 lf->lno_s = lr->offset + lr->start;
1715 if (lf->lno_s < 0) /* Overflow */
1716 lf->lno_s = INT_MAX;
1717 lf->lno_e = lr->offset + lr->end;
1718 if (lf->lno_e < 0) /* Overflow */
1719 lf->lno_e = INT_MAX;
1720 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1721 lr->start = lf->lno_s;
1722 lr->end = lf->lno_e;
1723 if (!die_is_func_instance(sp_die))
1724 param->retval = die_walk_instances(sp_die,
1725 line_range_inline_cb, lf);
1726 else
1727 param->retval = find_line_range_by_line(sp_die, lf);
1728 return DWARF_CB_ABORT;
1729 }
1730 return DWARF_CB_OK;
1731 }
1732
1733 static int find_line_range_by_func(struct line_finder *lf)
1734 {
1735 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1736 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1737 return param.retval;
1738 }
1739
1740 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1741 {
1742 struct line_finder lf = {.lr = lr, .found = 0};
1743 int ret = 0;
1744 Dwarf_Off off = 0, noff;
1745 size_t cuhl;
1746 Dwarf_Die *diep;
1747 const char *comp_dir;
1748
1749 /* Fastpath: lookup by function name from .debug_pubnames section */
1750 if (lr->function) {
1751 struct pubname_callback_param pubname_param = {
1752 .function = lr->function, .file = lr->file,
1753 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1754 struct dwarf_callback_param line_range_param = {
1755 .data = (void *)&lf, .retval = 0};
1756
1757 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1758 &pubname_param, 0);
1759 if (pubname_param.found) {
1760 line_range_search_cb(&lf.sp_die, &line_range_param);
1761 if (lf.found)
1762 goto found;
1763 }
1764 }
1765
1766 /* Loop on CUs (Compilation Unit) */
1767 while (!lf.found && ret >= 0) {
1768 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1769 NULL, NULL, NULL) != 0)
1770 break;
1771
1772 /* Get the DIE(Debugging Information Entry) of this CU */
1773 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1774 if (!diep)
1775 continue;
1776
1777 /* Check if target file is included. */
1778 if (lr->file)
1779 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1780 else
1781 lf.fname = 0;
1782
1783 if (!lr->file || lf.fname) {
1784 if (lr->function)
1785 ret = find_line_range_by_func(&lf);
1786 else {
1787 lf.lno_s = lr->start;
1788 lf.lno_e = lr->end;
1789 ret = find_line_range_by_line(NULL, &lf);
1790 }
1791 }
1792 off = noff;
1793 }
1794
1795 found:
1796 /* Store comp_dir */
1797 if (lf.found) {
1798 comp_dir = cu_get_comp_dir(&lf.cu_die);
1799 if (comp_dir) {
1800 lr->comp_dir = strdup(comp_dir);
1801 if (!lr->comp_dir)
1802 ret = -ENOMEM;
1803 }
1804 }
1805
1806 pr_debug("path: %s\n", lr->path);
1807 return (ret < 0) ? ret : lf.found;
1808 }
1809
1810 /*
1811 * Find a src file from a DWARF tag path. Prepend optional source path prefix
1812 * and chop off leading directories that do not exist. Result is passed back as
1813 * a newly allocated path on success.
1814 * Return 0 if file was found and readable, -errno otherwise.
1815 */
1816 int get_real_path(const char *raw_path, const char *comp_dir,
1817 char **new_path)
1818 {
1819 const char *prefix = symbol_conf.source_prefix;
1820
1821 if (!prefix) {
1822 if (raw_path[0] != '/' && comp_dir)
1823 /* If not an absolute path, try to use comp_dir */
1824 prefix = comp_dir;
1825 else {
1826 if (access(raw_path, R_OK) == 0) {
1827 *new_path = strdup(raw_path);
1828 return *new_path ? 0 : -ENOMEM;
1829 } else
1830 return -errno;
1831 }
1832 }
1833
1834 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1835 if (!*new_path)
1836 return -ENOMEM;
1837
1838 for (;;) {
1839 sprintf(*new_path, "%s/%s", prefix, raw_path);
1840
1841 if (access(*new_path, R_OK) == 0)
1842 return 0;
1843
1844 if (!symbol_conf.source_prefix) {
1845 /* In case of searching comp_dir, don't retry */
1846 zfree(new_path);
1847 return -errno;
1848 }
1849
1850 switch (errno) {
1851 case ENAMETOOLONG:
1852 case ENOENT:
1853 case EROFS:
1854 case EFAULT:
1855 raw_path = strchr(++raw_path, '/');
1856 if (!raw_path) {
1857 zfree(new_path);
1858 return -ENOENT;
1859 }
1860 continue;
1861
1862 default:
1863 zfree(new_path);
1864 return -errno;
1865 }
1866 }
1867 }
Linux with added FPC-III support