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KVM: PPC: Book3S HV: Flush link stack on guest exit to host kernel
[linux/fpc-iii.git] / tools / perf / util / probe-finder.c
blobcd9f95e5044e3df7f0155b7a49862e62bb7f75d6
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * probe-finder.c : C expression to kprobe event converter
4 *
5 * Written by Masami Hiramatsu <mhiramat@redhat.com>
6 */
7
8 #include <inttypes.h>
9 #include <sys/utsname.h>
10 #include <sys/types.h>
11 #include <sys/stat.h>
12 #include <fcntl.h>
13 #include <errno.h>
14 #include <stdio.h>
15 #include <unistd.h>
16 #include <stdlib.h>
17 #include <string.h>
18 #include <stdarg.h>
19 #include <dwarf-regs.h>
20
21 #include <linux/bitops.h>
22 #include <linux/zalloc.h>
23 #include "event.h"
24 #include "dso.h"
25 #include "debug.h"
26 #include "intlist.h"
27 #include "strbuf.h"
28 #include "strlist.h"
29 #include "symbol.h"
30 #include "probe-finder.h"
31 #include "probe-file.h"
32 #include "string2.h"
33
34 /* Kprobe tracer basic type is up to u64 */
35 #define MAX_BASIC_TYPE_BITS 64
36
37 /* Dwarf FL wrappers */
38 static char *debuginfo_path; /* Currently dummy */
39
40 static const Dwfl_Callbacks offline_callbacks = {
41 .find_debuginfo = dwfl_standard_find_debuginfo,
42 .debuginfo_path = &debuginfo_path,
43
44 .section_address = dwfl_offline_section_address,
45
46 /* We use this table for core files too. */
47 .find_elf = dwfl_build_id_find_elf,
48 };
49
50 /* Get a Dwarf from offline image */
51 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
52 const char *path)
53 {
54 int fd;
55
56 fd = open(path, O_RDONLY);
57 if (fd < 0)
58 return fd;
59
60 dbg->dwfl = dwfl_begin(&offline_callbacks);
61 if (!dbg->dwfl)
62 goto error;
63
64 dwfl_report_begin(dbg->dwfl);
65 dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
66 if (!dbg->mod)
67 goto error;
68
69 dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
70 if (!dbg->dbg)
71 goto error;
72
73 dwfl_report_end(dbg->dwfl, NULL, NULL);
74
75 return 0;
76 error:
77 if (dbg->dwfl)
78 dwfl_end(dbg->dwfl);
79 else
80 close(fd);
81 memset(dbg, 0, sizeof(*dbg));
82
83 return -ENOENT;
84 }
85
86 static struct debuginfo *__debuginfo__new(const char *path)
87 {
88 struct debuginfo *dbg = zalloc(sizeof(*dbg));
89 if (!dbg)
90 return NULL;
91
92 if (debuginfo__init_offline_dwarf(dbg, path) < 0)
93 zfree(&dbg);
94 if (dbg)
95 pr_debug("Open Debuginfo file: %s\n", path);
96 return dbg;
97 }
98
99 enum dso_binary_type distro_dwarf_types[] = {
100 DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
101 DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
102 DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
103 DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
104 DSO_BINARY_TYPE__NOT_FOUND,
105 };
106
107 struct debuginfo *debuginfo__new(const char *path)
108 {
109 enum dso_binary_type *type;
110 char buf[PATH_MAX], nil = '\0';
111 struct dso *dso;
112 struct debuginfo *dinfo = NULL;
113
114 /* Try to open distro debuginfo files */
115 dso = dso__new(path);
116 if (!dso)
117 goto out;
118
119 for (type = distro_dwarf_types;
120 !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
121 type++) {
122 if (dso__read_binary_type_filename(dso, *type, &nil,
123 buf, PATH_MAX) < 0)
124 continue;
125 dinfo = __debuginfo__new(buf);
126 }
127 dso__put(dso);
128
129 out:
130 /* if failed to open all distro debuginfo, open given binary */
131 return dinfo ? : __debuginfo__new(path);
132 }
133
134 void debuginfo__delete(struct debuginfo *dbg)
135 {
136 if (dbg) {
137 if (dbg->dwfl)
138 dwfl_end(dbg->dwfl);
139 free(dbg);
140 }
141 }
142
143 /*
144 * Probe finder related functions
145 */
146
147 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
148 {
149 struct probe_trace_arg_ref *ref;
150 ref = zalloc(sizeof(struct probe_trace_arg_ref));
151 if (ref != NULL)
152 ref->offset = offs;
153 return ref;
154 }
155
156 /*
157 * Convert a location into trace_arg.
158 * If tvar == NULL, this just checks variable can be converted.
159 * If fentry == true and vr_die is a parameter, do huristic search
160 * for the location fuzzed by function entry mcount.
161 */
162 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
163 Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
164 unsigned int machine,
165 struct probe_trace_arg *tvar)
166 {
167 Dwarf_Attribute attr;
168 Dwarf_Addr tmp = 0;
169 Dwarf_Op *op;
170 size_t nops;
171 unsigned int regn;
172 Dwarf_Word offs = 0;
173 bool ref = false;
174 const char *regs;
175 int ret, ret2 = 0;
176
177 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
178 goto static_var;
179
180 /* TODO: handle more than 1 exprs */
181 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
182 return -EINVAL; /* Broken DIE ? */
183 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
184 ret = dwarf_entrypc(sp_die, &tmp);
185 if (ret)
186 return -ENOENT;
187
188 if (probe_conf.show_location_range &&
189 (dwarf_tag(vr_die) == DW_TAG_variable)) {
190 ret2 = -ERANGE;
191 } else if (addr != tmp ||
192 dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
193 return -ENOENT;
194 }
195
196 ret = dwarf_highpc(sp_die, &tmp);
197 if (ret)
198 return -ENOENT;
199 /*
200 * This is fuzzed by fentry mcount. We try to find the
201 * parameter location at the earliest address.
202 */
203 for (addr += 1; addr <= tmp; addr++) {
204 if (dwarf_getlocation_addr(&attr, addr, &op,
205 &nops, 1) > 0)
206 goto found;
207 }
208 return -ENOENT;
209 }
210 found:
211 if (nops == 0)
212 /* TODO: Support const_value */
213 return -ENOENT;
214
215 if (op->atom == DW_OP_addr) {
216 static_var:
217 if (!tvar)
218 return ret2;
219 /* Static variables on memory (not stack), make @varname */
220 ret = strlen(dwarf_diename(vr_die));
221 tvar->value = zalloc(ret + 2);
222 if (tvar->value == NULL)
223 return -ENOMEM;
224 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
225 tvar->ref = alloc_trace_arg_ref((long)offs);
226 if (tvar->ref == NULL)
227 return -ENOMEM;
228 return ret2;
229 }
230
231 /* If this is based on frame buffer, set the offset */
232 if (op->atom == DW_OP_fbreg) {
233 if (fb_ops == NULL)
234 return -ENOTSUP;
235 ref = true;
236 offs = op->number;
237 op = &fb_ops[0];
238 }
239
240 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
241 regn = op->atom - DW_OP_breg0;
242 offs += op->number;
243 ref = true;
244 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
245 regn = op->atom - DW_OP_reg0;
246 } else if (op->atom == DW_OP_bregx) {
247 regn = op->number;
248 offs += op->number2;
249 ref = true;
250 } else if (op->atom == DW_OP_regx) {
251 regn = op->number;
252 } else {
253 pr_debug("DW_OP %x is not supported.\n", op->atom);
254 return -ENOTSUP;
255 }
256
257 if (!tvar)
258 return ret2;
259
260 regs = get_dwarf_regstr(regn, machine);
261 if (!regs) {
262 /* This should be a bug in DWARF or this tool */
263 pr_warning("Mapping for the register number %u "
264 "missing on this architecture.\n", regn);
265 return -ENOTSUP;
266 }
267
268 tvar->value = strdup(regs);
269 if (tvar->value == NULL)
270 return -ENOMEM;
271
272 if (ref) {
273 tvar->ref = alloc_trace_arg_ref((long)offs);
274 if (tvar->ref == NULL)
275 return -ENOMEM;
276 }
277 return ret2;
278 }
279
280 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
281
282 static int convert_variable_type(Dwarf_Die *vr_die,
283 struct probe_trace_arg *tvar,
284 const char *cast, bool user_access)
285 {
286 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
287 Dwarf_Die type;
288 char buf[16];
289 char sbuf[STRERR_BUFSIZE];
290 int bsize, boffs, total;
291 int ret;
292 char prefix;
293
294 /* TODO: check all types */
295 if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
296 strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
297 /* Non string type is OK */
298 /* and respect signedness/hexadecimal cast */
299 tvar->type = strdup(cast);
300 return (tvar->type == NULL) ? -ENOMEM : 0;
301 }
302
303 bsize = dwarf_bitsize(vr_die);
304 if (bsize > 0) {
305 /* This is a bitfield */
306 boffs = dwarf_bitoffset(vr_die);
307 total = dwarf_bytesize(vr_die);
308 if (boffs < 0 || total < 0)
309 return -ENOENT;
310 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
311 BYTES_TO_BITS(total));
312 goto formatted;
313 }
314
315 if (die_get_real_type(vr_die, &type) == NULL) {
316 pr_warning("Failed to get a type information of %s.\n",
317 dwarf_diename(vr_die));
318 return -ENOENT;
319 }
320
321 pr_debug("%s type is %s.\n",
322 dwarf_diename(vr_die), dwarf_diename(&type));
323
324 if (cast && (!strcmp(cast, "string") || !strcmp(cast, "ustring"))) {
325 /* String type */
326 ret = dwarf_tag(&type);
327 if (ret != DW_TAG_pointer_type &&
328 ret != DW_TAG_array_type) {
329 pr_warning("Failed to cast into string: "
330 "%s(%s) is not a pointer nor array.\n",
331 dwarf_diename(vr_die), dwarf_diename(&type));
332 return -EINVAL;
333 }
334 if (die_get_real_type(&type, &type) == NULL) {
335 pr_warning("Failed to get a type"
336 " information.\n");
337 return -ENOENT;
338 }
339 if (ret == DW_TAG_pointer_type) {
340 while (*ref_ptr)
341 ref_ptr = &(*ref_ptr)->next;
342 /* Add new reference with offset +0 */
343 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
344 if (*ref_ptr == NULL) {
345 pr_warning("Out of memory error\n");
346 return -ENOMEM;
347 }
348 (*ref_ptr)->user_access = user_access;
349 }
350 if (!die_compare_name(&type, "char") &&
351 !die_compare_name(&type, "unsigned char")) {
352 pr_warning("Failed to cast into string: "
353 "%s is not (unsigned) char *.\n",
354 dwarf_diename(vr_die));
355 return -EINVAL;
356 }
357 tvar->type = strdup(cast);
358 return (tvar->type == NULL) ? -ENOMEM : 0;
359 }
360
361 if (cast && (strcmp(cast, "u") == 0))
362 prefix = 'u';
363 else if (cast && (strcmp(cast, "s") == 0))
364 prefix = 's';
365 else if (cast && (strcmp(cast, "x") == 0) &&
366 probe_type_is_available(PROBE_TYPE_X))
367 prefix = 'x';
368 else
369 prefix = die_is_signed_type(&type) ? 's' :
370 probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
371
372 ret = dwarf_bytesize(&type);
373 if (ret <= 0)
374 /* No size ... try to use default type */
375 return 0;
376 ret = BYTES_TO_BITS(ret);
377
378 /* Check the bitwidth */
379 if (ret > MAX_BASIC_TYPE_BITS) {
380 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
381 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
382 ret = MAX_BASIC_TYPE_BITS;
383 }
384 ret = snprintf(buf, 16, "%c%d", prefix, ret);
385
386 formatted:
387 if (ret < 0 || ret >= 16) {
388 if (ret >= 16)
389 ret = -E2BIG;
390 pr_warning("Failed to convert variable type: %s\n",
391 str_error_r(-ret, sbuf, sizeof(sbuf)));
392 return ret;
393 }
394 tvar->type = strdup(buf);
395 if (tvar->type == NULL)
396 return -ENOMEM;
397 return 0;
398 }
399
400 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
401 struct perf_probe_arg_field *field,
402 struct probe_trace_arg_ref **ref_ptr,
403 Dwarf_Die *die_mem, bool user_access)
404 {
405 struct probe_trace_arg_ref *ref = *ref_ptr;
406 Dwarf_Die type;
407 Dwarf_Word offs;
408 int ret, tag;
409
410 pr_debug("converting %s in %s\n", field->name, varname);
411 if (die_get_real_type(vr_die, &type) == NULL) {
412 pr_warning("Failed to get the type of %s.\n", varname);
413 return -ENOENT;
414 }
415 pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type),
416 (unsigned)dwarf_dieoffset(&type));
417 tag = dwarf_tag(&type);
418
419 if (field->name[0] == '[' &&
420 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
421 /* Save original type for next field or type */
422 memcpy(die_mem, &type, sizeof(*die_mem));
423 /* Get the type of this array */
424 if (die_get_real_type(&type, &type) == NULL) {
425 pr_warning("Failed to get the type of %s.\n", varname);
426 return -ENOENT;
427 }
428 pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type),
429 (unsigned)dwarf_dieoffset(&type));
430 if (tag == DW_TAG_pointer_type) {
431 ref = zalloc(sizeof(struct probe_trace_arg_ref));
432 if (ref == NULL)
433 return -ENOMEM;
434 if (*ref_ptr)
435 (*ref_ptr)->next = ref;
436 else
437 *ref_ptr = ref;
438 }
439 ref->offset += dwarf_bytesize(&type) * field->index;
440 ref->user_access = user_access;
441 goto next;
442 } else if (tag == DW_TAG_pointer_type) {
443 /* Check the pointer and dereference */
444 if (!field->ref) {
445 pr_err("Semantic error: %s must be referred by '->'\n",
446 field->name);
447 return -EINVAL;
448 }
449 /* Get the type pointed by this pointer */
450 if (die_get_real_type(&type, &type) == NULL) {
451 pr_warning("Failed to get the type of %s.\n", varname);
452 return -ENOENT;
453 }
454 /* Verify it is a data structure */
455 tag = dwarf_tag(&type);
456 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
457 pr_warning("%s is not a data structure nor a union.\n",
458 varname);
459 return -EINVAL;
460 }
461
462 ref = zalloc(sizeof(struct probe_trace_arg_ref));
463 if (ref == NULL)
464 return -ENOMEM;
465 if (*ref_ptr)
466 (*ref_ptr)->next = ref;
467 else
468 *ref_ptr = ref;
469 } else {
470 /* Verify it is a data structure */
471 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
472 pr_warning("%s is not a data structure nor a union.\n",
473 varname);
474 return -EINVAL;
475 }
476 if (field->name[0] == '[') {
477 pr_err("Semantic error: %s is not a pointer"
478 " nor array.\n", varname);
479 return -EINVAL;
480 }
481 /* While prcessing unnamed field, we don't care about this */
482 if (field->ref && dwarf_diename(vr_die)) {
483 pr_err("Semantic error: %s must be referred by '.'\n",
484 field->name);
485 return -EINVAL;
486 }
487 if (!ref) {
488 pr_warning("Structure on a register is not "
489 "supported yet.\n");
490 return -ENOTSUP;
491 }
492 }
493
494 if (die_find_member(&type, field->name, die_mem) == NULL) {
495 pr_warning("%s(type:%s) has no member %s.\n", varname,
496 dwarf_diename(&type), field->name);
497 return -EINVAL;
498 }
499
500 /* Get the offset of the field */
501 if (tag == DW_TAG_union_type) {
502 offs = 0;
503 } else {
504 ret = die_get_data_member_location(die_mem, &offs);
505 if (ret < 0) {
506 pr_warning("Failed to get the offset of %s.\n",
507 field->name);
508 return ret;
509 }
510 }
511 ref->offset += (long)offs;
512 ref->user_access = user_access;
513
514 /* If this member is unnamed, we need to reuse this field */
515 if (!dwarf_diename(die_mem))
516 return convert_variable_fields(die_mem, varname, field,
517 &ref, die_mem, user_access);
518
519 next:
520 /* Converting next field */
521 if (field->next)
522 return convert_variable_fields(die_mem, field->name,
523 field->next, &ref, die_mem, user_access);
524 else
525 return 0;
526 }
527
528 /* Show a variables in kprobe event format */
529 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
530 {
531 Dwarf_Die die_mem;
532 int ret;
533
534 pr_debug("Converting variable %s into trace event.\n",
535 dwarf_diename(vr_die));
536
537 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
538 &pf->sp_die, pf->machine, pf->tvar);
539 if (ret == -ENOENT || ret == -EINVAL) {
540 pr_err("Failed to find the location of the '%s' variable at this address.\n"
541 " Perhaps it has been optimized out.\n"
542 " Use -V with the --range option to show '%s' location range.\n",
543 pf->pvar->var, pf->pvar->var);
544 } else if (ret == -ENOTSUP)
545 pr_err("Sorry, we don't support this variable location yet.\n");
546 else if (ret == 0 && pf->pvar->field) {
547 ret = convert_variable_fields(vr_die, pf->pvar->var,
548 pf->pvar->field, &pf->tvar->ref,
549 &die_mem, pf->pvar->user_access);
550 vr_die = &die_mem;
551 }
552 if (ret == 0)
553 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type,
554 pf->pvar->user_access);
555 /* *expr will be cached in libdw. Don't free it. */
556 return ret;
557 }
558
559 /* Find a variable in a scope DIE */
560 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
561 {
562 Dwarf_Die vr_die;
563 char *buf, *ptr;
564 int ret = 0;
565
566 /* Copy raw parameters */
567 if (!is_c_varname(pf->pvar->var))
568 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
569
570 if (pf->pvar->name)
571 pf->tvar->name = strdup(pf->pvar->name);
572 else {
573 buf = synthesize_perf_probe_arg(pf->pvar);
574 if (!buf)
575 return -ENOMEM;
576 ptr = strchr(buf, ':'); /* Change type separator to _ */
577 if (ptr)
578 *ptr = '_';
579 pf->tvar->name = buf;
580 }
581 if (pf->tvar->name == NULL)
582 return -ENOMEM;
583
584 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
585 /* Search child die for local variables and parameters. */
586 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
587 /* Search again in global variables */
588 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
589 0, &vr_die)) {
590 pr_warning("Failed to find '%s' in this function.\n",
591 pf->pvar->var);
592 ret = -ENOENT;
593 }
594 }
595 if (ret >= 0)
596 ret = convert_variable(&vr_die, pf);
597
598 return ret;
599 }
600
601 /* Convert subprogram DIE to trace point */
602 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
603 Dwarf_Addr paddr, bool retprobe,
604 const char *function,
605 struct probe_trace_point *tp)
606 {
607 Dwarf_Addr eaddr, highaddr;
608 GElf_Sym sym;
609 const char *symbol;
610
611 /* Verify the address is correct */
612 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
613 pr_warning("Failed to get entry address of %s\n",
614 dwarf_diename(sp_die));
615 return -ENOENT;
616 }
617 if (dwarf_highpc(sp_die, &highaddr) != 0) {
618 pr_warning("Failed to get end address of %s\n",
619 dwarf_diename(sp_die));
620 return -ENOENT;
621 }
622 if (paddr > highaddr) {
623 pr_warning("Offset specified is greater than size of %s\n",
624 dwarf_diename(sp_die));
625 return -EINVAL;
626 }
627
628 symbol = dwarf_diename(sp_die);
629 if (!symbol) {
630 /* Try to get the symbol name from symtab */
631 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
632 if (!symbol) {
633 pr_warning("Failed to find symbol at 0x%lx\n",
634 (unsigned long)paddr);
635 return -ENOENT;
636 }
637 eaddr = sym.st_value;
638 }
639 tp->offset = (unsigned long)(paddr - eaddr);
640 tp->address = (unsigned long)paddr;
641 tp->symbol = strdup(symbol);
642 if (!tp->symbol)
643 return -ENOMEM;
644
645 /* Return probe must be on the head of a subprogram */
646 if (retprobe) {
647 if (eaddr != paddr) {
648 pr_warning("Failed to find \"%s%%return\",\n"
649 " because %s is an inlined function and"
650 " has no return point.\n", function,
651 function);
652 return -EINVAL;
653 }
654 tp->retprobe = true;
655 }
656
657 return 0;
658 }
659
660 /* Call probe_finder callback with scope DIE */
661 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
662 {
663 Dwarf_Attribute fb_attr;
664 Dwarf_Frame *frame = NULL;
665 size_t nops;
666 int ret;
667
668 if (!sc_die) {
669 pr_err("Caller must pass a scope DIE. Program error.\n");
670 return -EINVAL;
671 }
672
673 /* If not a real subprogram, find a real one */
674 if (!die_is_func_def(sc_die)) {
675 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
676 if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
677 pr_warning("Ignoring tail call from %s\n",
678 dwarf_diename(&pf->sp_die));
679 return 0;
680 } else {
681 pr_warning("Failed to find probe point in any "
682 "functions.\n");
683 return -ENOENT;
684 }
685 }
686 } else
687 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
688
689 /* Get the frame base attribute/ops from subprogram */
690 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
691 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
692 if (ret <= 0 || nops == 0) {
693 pf->fb_ops = NULL;
694 #if _ELFUTILS_PREREQ(0, 142)
695 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
696 (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
697 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
698 (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
699 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
700 pr_warning("Failed to get call frame on 0x%jx\n",
701 (uintmax_t)pf->addr);
702 free(frame);
703 return -ENOENT;
704 }
705 #endif
706 }
707
708 /* Call finder's callback handler */
709 ret = pf->callback(sc_die, pf);
710
711 /* Since *pf->fb_ops can be a part of frame. we should free it here. */
712 free(frame);
713 pf->fb_ops = NULL;
714
715 return ret;
716 }
717
718 struct find_scope_param {
719 const char *function;
720 const char *file;
721 int line;
722 int diff;
723 Dwarf_Die *die_mem;
724 bool found;
725 };
726
727 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
728 {
729 struct find_scope_param *fsp = data;
730 const char *file;
731 int lno;
732
733 /* Skip if declared file name does not match */
734 if (fsp->file) {
735 file = dwarf_decl_file(fn_die);
736 if (!file || strcmp(fsp->file, file) != 0)
737 return 0;
738 }
739 /* If the function name is given, that's what user expects */
740 if (fsp->function) {
741 if (die_match_name(fn_die, fsp->function)) {
742 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
743 fsp->found = true;
744 return 1;
745 }
746 } else {
747 /* With the line number, find the nearest declared DIE */
748 dwarf_decl_line(fn_die, &lno);
749 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
750 /* Keep a candidate and continue */
751 fsp->diff = fsp->line - lno;
752 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
753 fsp->found = true;
754 }
755 }
756 return 0;
757 }
758
759 /* Find an appropriate scope fits to given conditions */
760 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
761 {
762 struct find_scope_param fsp = {
763 .function = pf->pev->point.function,
764 .file = pf->fname,
765 .line = pf->lno,
766 .diff = INT_MAX,
767 .die_mem = die_mem,
768 .found = false,
769 };
770
771 cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
772
773 return fsp.found ? die_mem : NULL;
774 }
775
776 static int probe_point_line_walker(const char *fname, int lineno,
777 Dwarf_Addr addr, void *data)
778 {
779 struct probe_finder *pf = data;
780 Dwarf_Die *sc_die, die_mem;
781 int ret;
782
783 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
784 return 0;
785
786 pf->addr = addr;
787 sc_die = find_best_scope(pf, &die_mem);
788 if (!sc_die) {
789 pr_warning("Failed to find scope of probe point.\n");
790 return -ENOENT;
791 }
792
793 ret = call_probe_finder(sc_die, pf);
794
795 /* Continue if no error, because the line will be in inline function */
796 return ret < 0 ? ret : 0;
797 }
798
799 /* Find probe point from its line number */
800 static int find_probe_point_by_line(struct probe_finder *pf)
801 {
802 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
803 }
804
805 /* Find lines which match lazy pattern */
806 static int find_lazy_match_lines(struct intlist *list,
807 const char *fname, const char *pat)
808 {
809 FILE *fp;
810 char *line = NULL;
811 size_t line_len;
812 ssize_t len;
813 int count = 0, linenum = 1;
814 char sbuf[STRERR_BUFSIZE];
815
816 fp = fopen(fname, "r");
817 if (!fp) {
818 pr_warning("Failed to open %s: %s\n", fname,
819 str_error_r(errno, sbuf, sizeof(sbuf)));
820 return -errno;
821 }
822
823 while ((len = getline(&line, &line_len, fp)) > 0) {
824
825 if (line[len - 1] == '\n')
826 line[len - 1] = '\0';
827
828 if (strlazymatch(line, pat)) {
829 intlist__add(list, linenum);
830 count++;
831 }
832 linenum++;
833 }
834
835 if (ferror(fp))
836 count = -errno;
837 free(line);
838 fclose(fp);
839
840 if (count == 0)
841 pr_debug("No matched lines found in %s.\n", fname);
842 return count;
843 }
844
845 static int probe_point_lazy_walker(const char *fname, int lineno,
846 Dwarf_Addr addr, void *data)
847 {
848 struct probe_finder *pf = data;
849 Dwarf_Die *sc_die, die_mem;
850 int ret;
851
852 if (!intlist__has_entry(pf->lcache, lineno) ||
853 strtailcmp(fname, pf->fname) != 0)
854 return 0;
855
856 pr_debug("Probe line found: line:%d addr:0x%llx\n",
857 lineno, (unsigned long long)addr);
858 pf->addr = addr;
859 pf->lno = lineno;
860 sc_die = find_best_scope(pf, &die_mem);
861 if (!sc_die) {
862 pr_warning("Failed to find scope of probe point.\n");
863 return -ENOENT;
864 }
865
866 ret = call_probe_finder(sc_die, pf);
867
868 /*
869 * Continue if no error, because the lazy pattern will match
870 * to other lines
871 */
872 return ret < 0 ? ret : 0;
873 }
874
875 /* Find probe points from lazy pattern */
876 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
877 {
878 int ret = 0;
879 char *fpath;
880
881 if (intlist__empty(pf->lcache)) {
882 const char *comp_dir;
883
884 comp_dir = cu_get_comp_dir(&pf->cu_die);
885 ret = get_real_path(pf->fname, comp_dir, &fpath);
886 if (ret < 0) {
887 pr_warning("Failed to find source file path.\n");
888 return ret;
889 }
890
891 /* Matching lazy line pattern */
892 ret = find_lazy_match_lines(pf->lcache, fpath,
893 pf->pev->point.lazy_line);
894 free(fpath);
895 if (ret <= 0)
896 return ret;
897 }
898
899 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
900 }
901
902 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
903 {
904 struct perf_probe_point *pp = &pf->pev->point;
905
906 /* Not uprobe? */
907 if (!pf->pev->uprobes)
908 return;
909
910 /* Compiled with optimization? */
911 if (die_is_optimized_target(&pf->cu_die))
912 return;
913
914 /* Don't know entrypc? */
915 if (!pf->addr)
916 return;
917
918 /* Only FUNC and FUNC@SRC are eligible. */
919 if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
920 pp->offset || pp->abs_address)
921 return;
922
923 /* Not interested in func parameter? */
924 if (!perf_probe_with_var(pf->pev))
925 return;
926
927 pr_info("Target program is compiled without optimization. Skipping prologue.\n"
928 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
929 pf->addr);
930
931 die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
932 }
933
934 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
935 {
936 struct probe_finder *pf = data;
937 struct perf_probe_point *pp = &pf->pev->point;
938 Dwarf_Addr addr;
939 int ret;
940
941 if (pp->lazy_line)
942 ret = find_probe_point_lazy(in_die, pf);
943 else {
944 /* Get probe address */
945 if (dwarf_entrypc(in_die, &addr) != 0) {
946 pr_warning("Failed to get entry address of %s.\n",
947 dwarf_diename(in_die));
948 return -ENOENT;
949 }
950 if (addr == 0) {
951 pr_debug("%s has no valid entry address. skipped.\n",
952 dwarf_diename(in_die));
953 return -ENOENT;
954 }
955 pf->addr = addr;
956 pf->addr += pp->offset;
957 pr_debug("found inline addr: 0x%jx\n",
958 (uintmax_t)pf->addr);
959
960 ret = call_probe_finder(in_die, pf);
961 }
962
963 return ret;
964 }
965
966 /* Callback parameter with return value for libdw */
967 struct dwarf_callback_param {
968 void *data;
969 int retval;
970 };
971
972 /* Search function from function name */
973 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
974 {
975 struct dwarf_callback_param *param = data;
976 struct probe_finder *pf = param->data;
977 struct perf_probe_point *pp = &pf->pev->point;
978
979 /* Check tag and diename */
980 if (!die_is_func_def(sp_die) ||
981 !die_match_name(sp_die, pp->function))
982 return DWARF_CB_OK;
983
984 /* Check declared file */
985 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
986 return DWARF_CB_OK;
987
988 pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
989 (unsigned long)dwarf_dieoffset(sp_die));
990 pf->fname = dwarf_decl_file(sp_die);
991 if (pp->line) { /* Function relative line */
992 dwarf_decl_line(sp_die, &pf->lno);
993 pf->lno += pp->line;
994 param->retval = find_probe_point_by_line(pf);
995 } else if (die_is_func_instance(sp_die)) {
996 /* Instances always have the entry address */
997 dwarf_entrypc(sp_die, &pf->addr);
998 /* But in some case the entry address is 0 */
999 if (pf->addr == 0) {
1000 pr_debug("%s has no entry PC. Skipped\n",
1001 dwarf_diename(sp_die));
1002 param->retval = 0;
1003 /* Real function */
1004 } else if (pp->lazy_line)
1005 param->retval = find_probe_point_lazy(sp_die, pf);
1006 else {
1007 skip_prologue(sp_die, pf);
1008 pf->addr += pp->offset;
1009 /* TODO: Check the address in this function */
1010 param->retval = call_probe_finder(sp_die, pf);
1011 }
1012 } else if (!probe_conf.no_inlines) {
1013 /* Inlined function: search instances */
1014 param->retval = die_walk_instances(sp_die,
1015 probe_point_inline_cb, (void *)pf);
1016 /* This could be a non-existed inline definition */
1017 if (param->retval == -ENOENT)
1018 param->retval = 0;
1019 }
1020
1021 /* We need to find other candidates */
1022 if (strisglob(pp->function) && param->retval >= 0) {
1023 param->retval = 0; /* We have to clear the result */
1024 return DWARF_CB_OK;
1025 }
1026
1027 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1028 }
1029
1030 static int find_probe_point_by_func(struct probe_finder *pf)
1031 {
1032 struct dwarf_callback_param _param = {.data = (void *)pf,
1033 .retval = 0};
1034 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1035 return _param.retval;
1036 }
1037
1038 struct pubname_callback_param {
1039 char *function;
1040 char *file;
1041 Dwarf_Die *cu_die;
1042 Dwarf_Die *sp_die;
1043 int found;
1044 };
1045
1046 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1047 {
1048 struct pubname_callback_param *param = data;
1049
1050 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1051 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1052 return DWARF_CB_OK;
1053
1054 if (die_match_name(param->sp_die, param->function)) {
1055 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1056 return DWARF_CB_OK;
1057
1058 if (param->file &&
1059 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1060 return DWARF_CB_OK;
1061
1062 param->found = 1;
1063 return DWARF_CB_ABORT;
1064 }
1065 }
1066
1067 return DWARF_CB_OK;
1068 }
1069
1070 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1071 struct probe_finder *pf)
1072 {
1073 struct perf_probe_point *pp = &pf->pev->point;
1074 Dwarf_Off off, noff;
1075 size_t cuhl;
1076 Dwarf_Die *diep;
1077 int ret = 0;
1078
1079 off = 0;
1080 pf->lcache = intlist__new(NULL);
1081 if (!pf->lcache)
1082 return -ENOMEM;
1083
1084 /* Fastpath: lookup by function name from .debug_pubnames section */
1085 if (pp->function && !strisglob(pp->function)) {
1086 struct pubname_callback_param pubname_param = {
1087 .function = pp->function,
1088 .file = pp->file,
1089 .cu_die = &pf->cu_die,
1090 .sp_die = &pf->sp_die,
1091 .found = 0,
1092 };
1093 struct dwarf_callback_param probe_param = {
1094 .data = pf,
1095 };
1096
1097 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1098 &pubname_param, 0);
1099 if (pubname_param.found) {
1100 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1101 if (ret)
1102 goto found;
1103 }
1104 }
1105
1106 /* Loop on CUs (Compilation Unit) */
1107 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1108 /* Get the DIE(Debugging Information Entry) of this CU */
1109 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1110 if (!diep)
1111 continue;
1112
1113 /* Check if target file is included. */
1114 if (pp->file)
1115 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1116 else
1117 pf->fname = NULL;
1118
1119 if (!pp->file || pf->fname) {
1120 if (pp->function)
1121 ret = find_probe_point_by_func(pf);
1122 else if (pp->lazy_line)
1123 ret = find_probe_point_lazy(&pf->cu_die, pf);
1124 else {
1125 pf->lno = pp->line;
1126 ret = find_probe_point_by_line(pf);
1127 }
1128 if (ret < 0)
1129 break;
1130 }
1131 off = noff;
1132 }
1133
1134 found:
1135 intlist__delete(pf->lcache);
1136 pf->lcache = NULL;
1137
1138 return ret;
1139 }
1140
1141 /* Find probe points from debuginfo */
1142 static int debuginfo__find_probes(struct debuginfo *dbg,
1143 struct probe_finder *pf)
1144 {
1145 int ret = 0;
1146 Elf *elf;
1147 GElf_Ehdr ehdr;
1148
1149 if (pf->cfi_eh || pf->cfi_dbg)
1150 return debuginfo__find_probe_location(dbg, pf);
1151
1152 /* Get the call frame information from this dwarf */
1153 elf = dwarf_getelf(dbg->dbg);
1154 if (elf == NULL)
1155 return -EINVAL;
1156
1157 if (gelf_getehdr(elf, &ehdr) == NULL)
1158 return -EINVAL;
1159
1160 pf->machine = ehdr.e_machine;
1161
1162 #if _ELFUTILS_PREREQ(0, 142)
1163 do {
1164 GElf_Shdr shdr;
1165
1166 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1167 shdr.sh_type == SHT_PROGBITS)
1168 pf->cfi_eh = dwarf_getcfi_elf(elf);
1169
1170 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1171 } while (0);
1172 #endif
1173
1174 ret = debuginfo__find_probe_location(dbg, pf);
1175 return ret;
1176 }
1177
1178 struct local_vars_finder {
1179 struct probe_finder *pf;
1180 struct perf_probe_arg *args;
1181 bool vars;
1182 int max_args;
1183 int nargs;
1184 int ret;
1185 };
1186
1187 /* Collect available variables in this scope */
1188 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1189 {
1190 struct local_vars_finder *vf = data;
1191 struct probe_finder *pf = vf->pf;
1192 int tag;
1193
1194 tag = dwarf_tag(die_mem);
1195 if (tag == DW_TAG_formal_parameter ||
1196 (tag == DW_TAG_variable && vf->vars)) {
1197 if (convert_variable_location(die_mem, vf->pf->addr,
1198 vf->pf->fb_ops, &pf->sp_die,
1199 pf->machine, NULL) == 0) {
1200 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1201 if (vf->args[vf->nargs].var == NULL) {
1202 vf->ret = -ENOMEM;
1203 return DIE_FIND_CB_END;
1204 }
1205 pr_debug(" %s", vf->args[vf->nargs].var);
1206 vf->nargs++;
1207 }
1208 }
1209
1210 if (dwarf_haspc(die_mem, vf->pf->addr))
1211 return DIE_FIND_CB_CONTINUE;
1212 else
1213 return DIE_FIND_CB_SIBLING;
1214 }
1215
1216 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1217 struct perf_probe_arg *args)
1218 {
1219 Dwarf_Die die_mem;
1220 int i;
1221 int n = 0;
1222 struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1223 .max_args = MAX_PROBE_ARGS, .ret = 0};
1224
1225 for (i = 0; i < pf->pev->nargs; i++) {
1226 /* var never be NULL */
1227 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1228 vf.vars = true;
1229 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1230 /* Copy normal argument */
1231 args[n] = pf->pev->args[i];
1232 n++;
1233 continue;
1234 }
1235 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1236 vf.nargs = n;
1237 /* Special local variables */
1238 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1239 &die_mem);
1240 pr_debug(" (%d)\n", vf.nargs - n);
1241 if (vf.ret < 0)
1242 return vf.ret;
1243 n = vf.nargs;
1244 }
1245 return n;
1246 }
1247
1248 static bool trace_event_finder_overlap(struct trace_event_finder *tf)
1249 {
1250 int i;
1251
1252 for (i = 0; i < tf->ntevs; i++) {
1253 if (tf->pf.addr == tf->tevs[i].point.address)
1254 return true;
1255 }
1256 return false;
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 /*
1270 * For some reason (e.g. different column assigned to same address)
1271 * This callback can be called with the address which already passed.
1272 * Ignore it first.
1273 */
1274 if (trace_event_finder_overlap(tf))
1275 return 0;
1276
1277 /* Check number of tevs */
1278 if (tf->ntevs == tf->max_tevs) {
1279 pr_warning("Too many( > %d) probe point found.\n",
1280 tf->max_tevs);
1281 return -ERANGE;
1282 }
1283 tev = &tf->tevs[tf->ntevs++];
1284
1285 /* Trace point should be converted from subprogram DIE */
1286 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1287 pp->retprobe, pp->function, &tev->point);
1288 if (ret < 0)
1289 goto end;
1290
1291 tev->point.realname = strdup(dwarf_diename(sc_die));
1292 if (!tev->point.realname) {
1293 ret = -ENOMEM;
1294 goto end;
1295 }
1296
1297 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1298 tev->point.offset);
1299
1300 /* Expand special probe argument if exist */
1301 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1302 if (args == NULL) {
1303 ret = -ENOMEM;
1304 goto end;
1305 }
1306
1307 ret = expand_probe_args(sc_die, pf, args);
1308 if (ret < 0)
1309 goto end;
1310
1311 tev->nargs = ret;
1312 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1313 if (tev->args == NULL) {
1314 ret = -ENOMEM;
1315 goto end;
1316 }
1317
1318 /* Find each argument */
1319 for (i = 0; i < tev->nargs; i++) {
1320 pf->pvar = &args[i];
1321 pf->tvar = &tev->args[i];
1322 /* Variable should be found from scope DIE */
1323 ret = find_variable(sc_die, pf);
1324 if (ret != 0)
1325 break;
1326 }
1327
1328 end:
1329 if (ret) {
1330 clear_probe_trace_event(tev);
1331 tf->ntevs--;
1332 }
1333 free(args);
1334 return ret;
1335 }
1336
1337 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1338 int debuginfo__find_trace_events(struct debuginfo *dbg,
1339 struct perf_probe_event *pev,
1340 struct probe_trace_event **tevs)
1341 {
1342 struct trace_event_finder tf = {
1343 .pf = {.pev = pev, .callback = add_probe_trace_event},
1344 .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1345 int ret, i;
1346
1347 /* Allocate result tevs array */
1348 *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1349 if (*tevs == NULL)
1350 return -ENOMEM;
1351
1352 tf.tevs = *tevs;
1353 tf.ntevs = 0;
1354
1355 ret = debuginfo__find_probes(dbg, &tf.pf);
1356 if (ret < 0) {
1357 for (i = 0; i < tf.ntevs; i++)
1358 clear_probe_trace_event(&tf.tevs[i]);
1359 zfree(tevs);
1360 return ret;
1361 }
1362
1363 return (ret < 0) ? ret : tf.ntevs;
1364 }
1365
1366 /* Collect available variables in this scope */
1367 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1368 {
1369 struct available_var_finder *af = data;
1370 struct variable_list *vl;
1371 struct strbuf buf = STRBUF_INIT;
1372 int tag, ret;
1373
1374 vl = &af->vls[af->nvls - 1];
1375
1376 tag = dwarf_tag(die_mem);
1377 if (tag == DW_TAG_formal_parameter ||
1378 tag == DW_TAG_variable) {
1379 ret = convert_variable_location(die_mem, af->pf.addr,
1380 af->pf.fb_ops, &af->pf.sp_die,
1381 af->pf.machine, NULL);
1382 if (ret == 0 || ret == -ERANGE) {
1383 int ret2;
1384 bool externs = !af->child;
1385
1386 if (strbuf_init(&buf, 64) < 0)
1387 goto error;
1388
1389 if (probe_conf.show_location_range) {
1390 if (!externs)
1391 ret2 = strbuf_add(&buf,
1392 ret ? "[INV]\t" : "[VAL]\t", 6);
1393 else
1394 ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1395 if (ret2)
1396 goto error;
1397 }
1398
1399 ret2 = die_get_varname(die_mem, &buf);
1400
1401 if (!ret2 && probe_conf.show_location_range &&
1402 !externs) {
1403 if (strbuf_addch(&buf, '\t') < 0)
1404 goto error;
1405 ret2 = die_get_var_range(&af->pf.sp_die,
1406 die_mem, &buf);
1407 }
1408
1409 pr_debug("Add new var: %s\n", buf.buf);
1410 if (ret2 == 0) {
1411 strlist__add(vl->vars,
1412 strbuf_detach(&buf, NULL));
1413 }
1414 strbuf_release(&buf);
1415 }
1416 }
1417
1418 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1419 return DIE_FIND_CB_CONTINUE;
1420 else
1421 return DIE_FIND_CB_SIBLING;
1422 error:
1423 strbuf_release(&buf);
1424 pr_debug("Error in strbuf\n");
1425 return DIE_FIND_CB_END;
1426 }
1427
1428 /* Add a found vars into available variables list */
1429 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1430 {
1431 struct available_var_finder *af =
1432 container_of(pf, struct available_var_finder, pf);
1433 struct perf_probe_point *pp = &pf->pev->point;
1434 struct variable_list *vl;
1435 Dwarf_Die die_mem;
1436 int ret;
1437
1438 /* Check number of tevs */
1439 if (af->nvls == af->max_vls) {
1440 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1441 return -ERANGE;
1442 }
1443 vl = &af->vls[af->nvls++];
1444
1445 /* Trace point should be converted from subprogram DIE */
1446 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1447 pp->retprobe, pp->function, &vl->point);
1448 if (ret < 0)
1449 return ret;
1450
1451 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1452 vl->point.offset);
1453
1454 /* Find local variables */
1455 vl->vars = strlist__new(NULL, NULL);
1456 if (vl->vars == NULL)
1457 return -ENOMEM;
1458 af->child = true;
1459 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1460
1461 /* Find external variables */
1462 if (!probe_conf.show_ext_vars)
1463 goto out;
1464 /* Don't need to search child DIE for external vars. */
1465 af->child = false;
1466 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1467
1468 out:
1469 if (strlist__empty(vl->vars)) {
1470 strlist__delete(vl->vars);
1471 vl->vars = NULL;
1472 }
1473
1474 return ret;
1475 }
1476
1477 /*
1478 * Find available variables at given probe point
1479 * Return the number of found probe points. Return 0 if there is no
1480 * matched probe point. Return <0 if an error occurs.
1481 */
1482 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1483 struct perf_probe_event *pev,
1484 struct variable_list **vls)
1485 {
1486 struct available_var_finder af = {
1487 .pf = {.pev = pev, .callback = add_available_vars},
1488 .mod = dbg->mod,
1489 .max_vls = probe_conf.max_probes};
1490 int ret;
1491
1492 /* Allocate result vls array */
1493 *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1494 if (*vls == NULL)
1495 return -ENOMEM;
1496
1497 af.vls = *vls;
1498 af.nvls = 0;
1499
1500 ret = debuginfo__find_probes(dbg, &af.pf);
1501 if (ret < 0) {
1502 /* Free vlist for error */
1503 while (af.nvls--) {
1504 zfree(&af.vls[af.nvls].point.symbol);
1505 strlist__delete(af.vls[af.nvls].vars);
1506 }
1507 zfree(vls);
1508 return ret;
1509 }
1510
1511 return (ret < 0) ? ret : af.nvls;
1512 }
1513
1514 /* For the kernel module, we need a special code to get a DIE */
1515 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1516 bool adjust_offset)
1517 {
1518 int n, i;
1519 Elf32_Word shndx;
1520 Elf_Scn *scn;
1521 Elf *elf;
1522 GElf_Shdr mem, *shdr;
1523 const char *p;
1524
1525 elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1526 if (!elf)
1527 return -EINVAL;
1528
1529 /* Get the number of relocations */
1530 n = dwfl_module_relocations(dbg->mod);
1531 if (n < 0)
1532 return -ENOENT;
1533 /* Search the relocation related .text section */
1534 for (i = 0; i < n; i++) {
1535 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1536 if (strcmp(p, ".text") == 0) {
1537 /* OK, get the section header */
1538 scn = elf_getscn(elf, shndx);
1539 if (!scn)
1540 return -ENOENT;
1541 shdr = gelf_getshdr(scn, &mem);
1542 if (!shdr)
1543 return -ENOENT;
1544 *offs = shdr->sh_addr;
1545 if (adjust_offset)
1546 *offs -= shdr->sh_offset;
1547 }
1548 }
1549 return 0;
1550 }
1551
1552 /* Reverse search */
1553 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1554 struct perf_probe_point *ppt)
1555 {
1556 Dwarf_Die cudie, spdie, indie;
1557 Dwarf_Addr _addr = 0, baseaddr = 0;
1558 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1559 int baseline = 0, lineno = 0, ret = 0;
1560
1561 /* We always need to relocate the address for aranges */
1562 if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1563 addr += baseaddr;
1564 /* Find cu die */
1565 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1566 pr_warning("Failed to find debug information for address %lx\n",
1567 addr);
1568 ret = -EINVAL;
1569 goto end;
1570 }
1571
1572 /* Find a corresponding line (filename and lineno) */
1573 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1574 /* Don't care whether it failed or not */
1575
1576 /* Find a corresponding function (name, baseline and baseaddr) */
1577 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1578 /* Get function entry information */
1579 func = basefunc = dwarf_diename(&spdie);
1580 if (!func ||
1581 dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1582 dwarf_decl_line(&spdie, &baseline) != 0) {
1583 lineno = 0;
1584 goto post;
1585 }
1586
1587 fname = dwarf_decl_file(&spdie);
1588 if (addr == (unsigned long)baseaddr) {
1589 /* Function entry - Relative line number is 0 */
1590 lineno = baseline;
1591 goto post;
1592 }
1593
1594 /* Track down the inline functions step by step */
1595 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1596 &indie)) {
1597 /* There is an inline function */
1598 if (dwarf_entrypc(&indie, &_addr) == 0 &&
1599 _addr == addr) {
1600 /*
1601 * addr is at an inline function entry.
1602 * In this case, lineno should be the call-site
1603 * line number. (overwrite lineinfo)
1604 */
1605 lineno = die_get_call_lineno(&indie);
1606 fname = die_get_call_file(&indie);
1607 break;
1608 } else {
1609 /*
1610 * addr is in an inline function body.
1611 * Since lineno points one of the lines
1612 * of the inline function, baseline should
1613 * be the entry line of the inline function.
1614 */
1615 tmp = dwarf_diename(&indie);
1616 if (!tmp ||
1617 dwarf_decl_line(&indie, &baseline) != 0)
1618 break;
1619 func = tmp;
1620 spdie = indie;
1621 }
1622 }
1623 /* Verify the lineno and baseline are in a same file */
1624 tmp = dwarf_decl_file(&spdie);
1625 if (!tmp || strcmp(tmp, fname) != 0)
1626 lineno = 0;
1627 }
1628
1629 post:
1630 /* Make a relative line number or an offset */
1631 if (lineno)
1632 ppt->line = lineno - baseline;
1633 else if (basefunc) {
1634 ppt->offset = addr - (unsigned long)baseaddr;
1635 func = basefunc;
1636 }
1637
1638 /* Duplicate strings */
1639 if (func) {
1640 ppt->function = strdup(func);
1641 if (ppt->function == NULL) {
1642 ret = -ENOMEM;
1643 goto end;
1644 }
1645 }
1646 if (fname) {
1647 ppt->file = strdup(fname);
1648 if (ppt->file == NULL) {
1649 zfree(&ppt->function);
1650 ret = -ENOMEM;
1651 goto end;
1652 }
1653 }
1654 end:
1655 if (ret == 0 && (fname || func))
1656 ret = 1; /* Found a point */
1657 return ret;
1658 }
1659
1660 /* Add a line and store the src path */
1661 static int line_range_add_line(const char *src, unsigned int lineno,
1662 struct line_range *lr)
1663 {
1664 /* Copy source path */
1665 if (!lr->path) {
1666 lr->path = strdup(src);
1667 if (lr->path == NULL)
1668 return -ENOMEM;
1669 }
1670 return intlist__add(lr->line_list, lineno);
1671 }
1672
1673 static int line_range_walk_cb(const char *fname, int lineno,
1674 Dwarf_Addr addr __maybe_unused,
1675 void *data)
1676 {
1677 struct line_finder *lf = data;
1678 int err;
1679
1680 if ((strtailcmp(fname, lf->fname) != 0) ||
1681 (lf->lno_s > lineno || lf->lno_e < lineno))
1682 return 0;
1683
1684 err = line_range_add_line(fname, lineno, lf->lr);
1685 if (err < 0 && err != -EEXIST)
1686 return err;
1687
1688 return 0;
1689 }
1690
1691 /* Find line range from its line number */
1692 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1693 {
1694 int ret;
1695
1696 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1697
1698 /* Update status */
1699 if (ret >= 0)
1700 if (!intlist__empty(lf->lr->line_list))
1701 ret = lf->found = 1;
1702 else
1703 ret = 0; /* Lines are not found */
1704 else {
1705 zfree(&lf->lr->path);
1706 }
1707 return ret;
1708 }
1709
1710 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1711 {
1712 int ret = find_line_range_by_line(in_die, data);
1713
1714 /*
1715 * We have to check all instances of inlined function, because
1716 * some execution paths can be optimized out depends on the
1717 * function argument of instances. However, if an error occurs,
1718 * it should be handled by the caller.
1719 */
1720 return ret < 0 ? ret : 0;
1721 }
1722
1723 /* Search function definition from function name */
1724 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1725 {
1726 struct dwarf_callback_param *param = data;
1727 struct line_finder *lf = param->data;
1728 struct line_range *lr = lf->lr;
1729
1730 /* Check declared file */
1731 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1732 return DWARF_CB_OK;
1733
1734 if (die_is_func_def(sp_die) &&
1735 die_match_name(sp_die, lr->function)) {
1736 lf->fname = dwarf_decl_file(sp_die);
1737 dwarf_decl_line(sp_die, &lr->offset);
1738 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1739 lf->lno_s = lr->offset + lr->start;
1740 if (lf->lno_s < 0) /* Overflow */
1741 lf->lno_s = INT_MAX;
1742 lf->lno_e = lr->offset + lr->end;
1743 if (lf->lno_e < 0) /* Overflow */
1744 lf->lno_e = INT_MAX;
1745 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1746 lr->start = lf->lno_s;
1747 lr->end = lf->lno_e;
1748 if (!die_is_func_instance(sp_die))
1749 param->retval = die_walk_instances(sp_die,
1750 line_range_inline_cb, lf);
1751 else
1752 param->retval = find_line_range_by_line(sp_die, lf);
1753 return DWARF_CB_ABORT;
1754 }
1755 return DWARF_CB_OK;
1756 }
1757
1758 static int find_line_range_by_func(struct line_finder *lf)
1759 {
1760 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1761 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1762 return param.retval;
1763 }
1764
1765 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1766 {
1767 struct line_finder lf = {.lr = lr, .found = 0};
1768 int ret = 0;
1769 Dwarf_Off off = 0, noff;
1770 size_t cuhl;
1771 Dwarf_Die *diep;
1772 const char *comp_dir;
1773
1774 /* Fastpath: lookup by function name from .debug_pubnames section */
1775 if (lr->function) {
1776 struct pubname_callback_param pubname_param = {
1777 .function = lr->function, .file = lr->file,
1778 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1779 struct dwarf_callback_param line_range_param = {
1780 .data = (void *)&lf, .retval = 0};
1781
1782 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1783 &pubname_param, 0);
1784 if (pubname_param.found) {
1785 line_range_search_cb(&lf.sp_die, &line_range_param);
1786 if (lf.found)
1787 goto found;
1788 }
1789 }
1790
1791 /* Loop on CUs (Compilation Unit) */
1792 while (!lf.found && ret >= 0) {
1793 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1794 NULL, NULL, NULL) != 0)
1795 break;
1796
1797 /* Get the DIE(Debugging Information Entry) of this CU */
1798 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1799 if (!diep)
1800 continue;
1801
1802 /* Check if target file is included. */
1803 if (lr->file)
1804 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1805 else
1806 lf.fname = 0;
1807
1808 if (!lr->file || lf.fname) {
1809 if (lr->function)
1810 ret = find_line_range_by_func(&lf);
1811 else {
1812 lf.lno_s = lr->start;
1813 lf.lno_e = lr->end;
1814 ret = find_line_range_by_line(NULL, &lf);
1815 }
1816 }
1817 off = noff;
1818 }
1819
1820 found:
1821 /* Store comp_dir */
1822 if (lf.found) {
1823 comp_dir = cu_get_comp_dir(&lf.cu_die);
1824 if (comp_dir) {
1825 lr->comp_dir = strdup(comp_dir);
1826 if (!lr->comp_dir)
1827 ret = -ENOMEM;
1828 }
1829 }
1830
1831 pr_debug("path: %s\n", lr->path);
1832 return (ret < 0) ? ret : lf.found;
1833 }
1834
1835 /*
1836 * Find a src file from a DWARF tag path. Prepend optional source path prefix
1837 * and chop off leading directories that do not exist. Result is passed back as
1838 * a newly allocated path on success.
1839 * Return 0 if file was found and readable, -errno otherwise.
1840 */
1841 int get_real_path(const char *raw_path, const char *comp_dir,
1842 char **new_path)
1843 {
1844 const char *prefix = symbol_conf.source_prefix;
1845
1846 if (!prefix) {
1847 if (raw_path[0] != '/' && comp_dir)
1848 /* If not an absolute path, try to use comp_dir */
1849 prefix = comp_dir;
1850 else {
1851 if (access(raw_path, R_OK) == 0) {
1852 *new_path = strdup(raw_path);
1853 return *new_path ? 0 : -ENOMEM;
1854 } else
1855 return -errno;
1856 }
1857 }
1858
1859 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1860 if (!*new_path)
1861 return -ENOMEM;
1862
1863 for (;;) {
1864 sprintf(*new_path, "%s/%s", prefix, raw_path);
1865
1866 if (access(*new_path, R_OK) == 0)
1867 return 0;
1868
1869 if (!symbol_conf.source_prefix) {
1870 /* In case of searching comp_dir, don't retry */
1871 zfree(new_path);
1872 return -errno;
1873 }
1874
1875 switch (errno) {
1876 case ENAMETOOLONG:
1877 case ENOENT:
1878 case EROFS:
1879 case EFAULT:
1880 raw_path = strchr(++raw_path, '/');
1881 if (!raw_path) {
1882 zfree(new_path);
1883 return -ENOENT;
1884 }
1885 continue;
1886
1887 default:
1888 zfree(new_path);
1889 return -errno;
1890 }
1891 }
1892 }
Linux with added FPC-III support