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perf probe: Find fentry mcount fuzzed parameter location
[deliverable/linux.git] / tools / perf / util / probe-finder.c
1 /*
2 * probe-finder.c : C expression to kprobe event converter
3 *
4 * Written by Masami Hiramatsu <mhiramat@redhat.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 *
20 */
21
22 #include <sys/utsname.h>
23 #include <sys/types.h>
24 #include <sys/stat.h>
25 #include <fcntl.h>
26 #include <errno.h>
27 #include <stdio.h>
28 #include <unistd.h>
29 #include <getopt.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <stdarg.h>
33 #include <dwarf-regs.h>
34
35 #include <linux/bitops.h>
36 #include "event.h"
37 #include "debug.h"
38 #include "util.h"
39 #include "symbol.h"
40 #include "probe-finder.h"
41
42 /* Kprobe tracer basic type is up to u64 */
43 #define MAX_BASIC_TYPE_BITS 64
44
45 /* Line number list operations */
46
47 /* Add a line to line number list */
48 static int line_list__add_line(struct list_head *head, int line)
49 {
50 struct line_node *ln;
51 struct list_head *p;
52
53 /* Reverse search, because new line will be the last one */
54 list_for_each_entry_reverse(ln, head, list) {
55 if (ln->line < line) {
56 p = &ln->list;
57 goto found;
58 } else if (ln->line == line) /* Already exist */
59 return 1;
60 }
61 /* List is empty, or the smallest entry */
62 p = head;
63 found:
64 pr_debug("line list: add a line %u\n", line);
65 ln = zalloc(sizeof(struct line_node));
66 if (ln == NULL)
67 return -ENOMEM;
68 ln->line = line;
69 INIT_LIST_HEAD(&ln->list);
70 list_add(&ln->list, p);
71 return 0;
72 }
73
74 /* Check if the line in line number list */
75 static int line_list__has_line(struct list_head *head, int line)
76 {
77 struct line_node *ln;
78
79 /* Reverse search, because new line will be the last one */
80 list_for_each_entry(ln, head, list)
81 if (ln->line == line)
82 return 1;
83
84 return 0;
85 }
86
87 /* Init line number list */
88 static void line_list__init(struct list_head *head)
89 {
90 INIT_LIST_HEAD(head);
91 }
92
93 /* Free line number list */
94 static void line_list__free(struct list_head *head)
95 {
96 struct line_node *ln;
97 while (!list_empty(head)) {
98 ln = list_first_entry(head, struct line_node, list);
99 list_del(&ln->list);
100 free(ln);
101 }
102 }
103
104 /* Dwarf FL wrappers */
105 static char *debuginfo_path; /* Currently dummy */
106
107 static const Dwfl_Callbacks offline_callbacks = {
108 .find_debuginfo = dwfl_standard_find_debuginfo,
109 .debuginfo_path = &debuginfo_path,
110
111 .section_address = dwfl_offline_section_address,
112
113 /* We use this table for core files too. */
114 .find_elf = dwfl_build_id_find_elf,
115 };
116
117 /* Get a Dwarf from offline image */
118 static int debuginfo__init_offline_dwarf(struct debuginfo *self,
119 const char *path)
120 {
121 int fd;
122
123 fd = open(path, O_RDONLY);
124 if (fd < 0)
125 return fd;
126
127 self->dwfl = dwfl_begin(&offline_callbacks);
128 if (!self->dwfl)
129 goto error;
130
131 self->mod = dwfl_report_offline(self->dwfl, "", "", fd);
132 if (!self->mod)
133 goto error;
134
135 self->dbg = dwfl_module_getdwarf(self->mod, &self->bias);
136 if (!self->dbg)
137 goto error;
138
139 return 0;
140 error:
141 if (self->dwfl)
142 dwfl_end(self->dwfl);
143 else
144 close(fd);
145 memset(self, 0, sizeof(*self));
146
147 return -ENOENT;
148 }
149
150 #if _ELFUTILS_PREREQ(0, 148)
151 /* This method is buggy if elfutils is older than 0.148 */
152 static int __linux_kernel_find_elf(Dwfl_Module *mod,
153 void **userdata,
154 const char *module_name,
155 Dwarf_Addr base,
156 char **file_name, Elf **elfp)
157 {
158 int fd;
159 const char *path = kernel_get_module_path(module_name);
160
161 pr_debug2("Use file %s for %s\n", path, module_name);
162 if (path) {
163 fd = open(path, O_RDONLY);
164 if (fd >= 0) {
165 *file_name = strdup(path);
166 return fd;
167 }
168 }
169 /* If failed, try to call standard method */
170 return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
171 file_name, elfp);
172 }
173
174 static const Dwfl_Callbacks kernel_callbacks = {
175 .find_debuginfo = dwfl_standard_find_debuginfo,
176 .debuginfo_path = &debuginfo_path,
177
178 .find_elf = __linux_kernel_find_elf,
179 .section_address = dwfl_linux_kernel_module_section_address,
180 };
181
182 /* Get a Dwarf from live kernel image */
183 static int debuginfo__init_online_kernel_dwarf(struct debuginfo *self,
184 Dwarf_Addr addr)
185 {
186 self->dwfl = dwfl_begin(&kernel_callbacks);
187 if (!self->dwfl)
188 return -EINVAL;
189
190 /* Load the kernel dwarves: Don't care the result here */
191 dwfl_linux_kernel_report_kernel(self->dwfl);
192 dwfl_linux_kernel_report_modules(self->dwfl);
193
194 self->dbg = dwfl_addrdwarf(self->dwfl, addr, &self->bias);
195 /* Here, check whether we could get a real dwarf */
196 if (!self->dbg) {
197 pr_debug("Failed to find kernel dwarf at %lx\n",
198 (unsigned long)addr);
199 dwfl_end(self->dwfl);
200 memset(self, 0, sizeof(*self));
201 return -ENOENT;
202 }
203
204 return 0;
205 }
206 #else
207 /* With older elfutils, this just support kernel module... */
208 static int debuginfo__init_online_kernel_dwarf(struct debuginfo *self,
209 Dwarf_Addr addr __maybe_unused)
210 {
211 const char *path = kernel_get_module_path("kernel");
212
213 if (!path) {
214 pr_err("Failed to find vmlinux path\n");
215 return -ENOENT;
216 }
217
218 pr_debug2("Use file %s for debuginfo\n", path);
219 return debuginfo__init_offline_dwarf(self, path);
220 }
221 #endif
222
223 struct debuginfo *debuginfo__new(const char *path)
224 {
225 struct debuginfo *self = zalloc(sizeof(struct debuginfo));
226 if (!self)
227 return NULL;
228
229 if (debuginfo__init_offline_dwarf(self, path) < 0) {
230 free(self);
231 self = NULL;
232 }
233
234 return self;
235 }
236
237 struct debuginfo *debuginfo__new_online_kernel(unsigned long addr)
238 {
239 struct debuginfo *self = zalloc(sizeof(struct debuginfo));
240 if (!self)
241 return NULL;
242
243 if (debuginfo__init_online_kernel_dwarf(self, (Dwarf_Addr)addr) < 0) {
244 free(self);
245 self = NULL;
246 }
247
248 return self;
249 }
250
251 void debuginfo__delete(struct debuginfo *self)
252 {
253 if (self) {
254 if (self->dwfl)
255 dwfl_end(self->dwfl);
256 free(self);
257 }
258 }
259
260 /*
261 * Probe finder related functions
262 */
263
264 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
265 {
266 struct probe_trace_arg_ref *ref;
267 ref = zalloc(sizeof(struct probe_trace_arg_ref));
268 if (ref != NULL)
269 ref->offset = offs;
270 return ref;
271 }
272
273 /*
274 * Convert a location into trace_arg.
275 * If tvar == NULL, this just checks variable can be converted.
276 * If fentry == true and vr_die is a parameter, do huristic search
277 * for the location fuzzed by function entry mcount.
278 */
279 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
280 Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
281 struct probe_trace_arg *tvar)
282 {
283 Dwarf_Attribute attr;
284 Dwarf_Addr tmp = 0;
285 Dwarf_Op *op;
286 size_t nops;
287 unsigned int regn;
288 Dwarf_Word offs = 0;
289 bool ref = false;
290 const char *regs;
291 int ret;
292
293 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
294 goto static_var;
295
296 /* TODO: handle more than 1 exprs */
297 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
298 return -EINVAL; /* Broken DIE ? */
299 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
300 ret = dwarf_entrypc(sp_die, &tmp);
301 if (ret || addr != tmp ||
302 dwarf_tag(vr_die) != DW_TAG_formal_parameter ||
303 dwarf_highpc(sp_die, &tmp))
304 return -ENOENT;
305 /*
306 * This is fuzzed by fentry mcount. We try to find the
307 * parameter location at the earliest address.
308 */
309 for (addr += 1; addr <= tmp; addr++) {
310 if (dwarf_getlocation_addr(&attr, addr, &op,
311 &nops, 1) > 0)
312 goto found;
313 }
314 return -ENOENT;
315 }
316 found:
317 if (nops == 0)
318 /* TODO: Support const_value */
319 return -ENOENT;
320
321 if (op->atom == DW_OP_addr) {
322 static_var:
323 if (!tvar)
324 return 0;
325 /* Static variables on memory (not stack), make @varname */
326 ret = strlen(dwarf_diename(vr_die));
327 tvar->value = zalloc(ret + 2);
328 if (tvar->value == NULL)
329 return -ENOMEM;
330 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
331 tvar->ref = alloc_trace_arg_ref((long)offs);
332 if (tvar->ref == NULL)
333 return -ENOMEM;
334 return 0;
335 }
336
337 /* If this is based on frame buffer, set the offset */
338 if (op->atom == DW_OP_fbreg) {
339 if (fb_ops == NULL)
340 return -ENOTSUP;
341 ref = true;
342 offs = op->number;
343 op = &fb_ops[0];
344 }
345
346 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
347 regn = op->atom - DW_OP_breg0;
348 offs += op->number;
349 ref = true;
350 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
351 regn = op->atom - DW_OP_reg0;
352 } else if (op->atom == DW_OP_bregx) {
353 regn = op->number;
354 offs += op->number2;
355 ref = true;
356 } else if (op->atom == DW_OP_regx) {
357 regn = op->number;
358 } else {
359 pr_debug("DW_OP %x is not supported.\n", op->atom);
360 return -ENOTSUP;
361 }
362
363 if (!tvar)
364 return 0;
365
366 regs = get_arch_regstr(regn);
367 if (!regs) {
368 /* This should be a bug in DWARF or this tool */
369 pr_warning("Mapping for the register number %u "
370 "missing on this architecture.\n", regn);
371 return -ERANGE;
372 }
373
374 tvar->value = strdup(regs);
375 if (tvar->value == NULL)
376 return -ENOMEM;
377
378 if (ref) {
379 tvar->ref = alloc_trace_arg_ref((long)offs);
380 if (tvar->ref == NULL)
381 return -ENOMEM;
382 }
383 return 0;
384 }
385
386 #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
387
388 static int convert_variable_type(Dwarf_Die *vr_die,
389 struct probe_trace_arg *tvar,
390 const char *cast)
391 {
392 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
393 Dwarf_Die type;
394 char buf[16];
395 int bsize, boffs, total;
396 int ret;
397
398 /* TODO: check all types */
399 if (cast && strcmp(cast, "string") != 0) {
400 /* Non string type is OK */
401 tvar->type = strdup(cast);
402 return (tvar->type == NULL) ? -ENOMEM : 0;
403 }
404
405 bsize = dwarf_bitsize(vr_die);
406 if (bsize > 0) {
407 /* This is a bitfield */
408 boffs = dwarf_bitoffset(vr_die);
409 total = dwarf_bytesize(vr_die);
410 if (boffs < 0 || total < 0)
411 return -ENOENT;
412 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
413 BYTES_TO_BITS(total));
414 goto formatted;
415 }
416
417 if (die_get_real_type(vr_die, &type) == NULL) {
418 pr_warning("Failed to get a type information of %s.\n",
419 dwarf_diename(vr_die));
420 return -ENOENT;
421 }
422
423 pr_debug("%s type is %s.\n",
424 dwarf_diename(vr_die), dwarf_diename(&type));
425
426 if (cast && strcmp(cast, "string") == 0) { /* String type */
427 ret = dwarf_tag(&type);
428 if (ret != DW_TAG_pointer_type &&
429 ret != DW_TAG_array_type) {
430 pr_warning("Failed to cast into string: "
431 "%s(%s) is not a pointer nor array.\n",
432 dwarf_diename(vr_die), dwarf_diename(&type));
433 return -EINVAL;
434 }
435 if (die_get_real_type(&type, &type) == NULL) {
436 pr_warning("Failed to get a type"
437 " information.\n");
438 return -ENOENT;
439 }
440 if (ret == DW_TAG_pointer_type) {
441 while (*ref_ptr)
442 ref_ptr = &(*ref_ptr)->next;
443 /* Add new reference with offset +0 */
444 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
445 if (*ref_ptr == NULL) {
446 pr_warning("Out of memory error\n");
447 return -ENOMEM;
448 }
449 }
450 if (!die_compare_name(&type, "char") &&
451 !die_compare_name(&type, "unsigned char")) {
452 pr_warning("Failed to cast into string: "
453 "%s is not (unsigned) char *.\n",
454 dwarf_diename(vr_die));
455 return -EINVAL;
456 }
457 tvar->type = strdup(cast);
458 return (tvar->type == NULL) ? -ENOMEM : 0;
459 }
460
461 ret = dwarf_bytesize(&type);
462 if (ret <= 0)
463 /* No size ... try to use default type */
464 return 0;
465 ret = BYTES_TO_BITS(ret);
466
467 /* Check the bitwidth */
468 if (ret > MAX_BASIC_TYPE_BITS) {
469 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
470 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
471 ret = MAX_BASIC_TYPE_BITS;
472 }
473 ret = snprintf(buf, 16, "%c%d",
474 die_is_signed_type(&type) ? 's' : 'u', ret);
475
476 formatted:
477 if (ret < 0 || ret >= 16) {
478 if (ret >= 16)
479 ret = -E2BIG;
480 pr_warning("Failed to convert variable type: %s\n",
481 strerror(-ret));
482 return ret;
483 }
484 tvar->type = strdup(buf);
485 if (tvar->type == NULL)
486 return -ENOMEM;
487 return 0;
488 }
489
490 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
491 struct perf_probe_arg_field *field,
492 struct probe_trace_arg_ref **ref_ptr,
493 Dwarf_Die *die_mem)
494 {
495 struct probe_trace_arg_ref *ref = *ref_ptr;
496 Dwarf_Die type;
497 Dwarf_Word offs;
498 int ret, tag;
499
500 pr_debug("converting %s in %s\n", field->name, varname);
501 if (die_get_real_type(vr_die, &type) == NULL) {
502 pr_warning("Failed to get the type of %s.\n", varname);
503 return -ENOENT;
504 }
505 pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
506 tag = dwarf_tag(&type);
507
508 if (field->name[0] == '[' &&
509 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
510 if (field->next)
511 /* Save original type for next field */
512 memcpy(die_mem, &type, sizeof(*die_mem));
513 /* Get the type of this array */
514 if (die_get_real_type(&type, &type) == NULL) {
515 pr_warning("Failed to get the type of %s.\n", varname);
516 return -ENOENT;
517 }
518 pr_debug2("Array real type: (%x)\n",
519 (unsigned)dwarf_dieoffset(&type));
520 if (tag == DW_TAG_pointer_type) {
521 ref = zalloc(sizeof(struct probe_trace_arg_ref));
522 if (ref == NULL)
523 return -ENOMEM;
524 if (*ref_ptr)
525 (*ref_ptr)->next = ref;
526 else
527 *ref_ptr = ref;
528 }
529 ref->offset += dwarf_bytesize(&type) * field->index;
530 if (!field->next)
531 /* Save vr_die for converting types */
532 memcpy(die_mem, vr_die, sizeof(*die_mem));
533 goto next;
534 } else if (tag == DW_TAG_pointer_type) {
535 /* Check the pointer and dereference */
536 if (!field->ref) {
537 pr_err("Semantic error: %s must be referred by '->'\n",
538 field->name);
539 return -EINVAL;
540 }
541 /* Get the type pointed by this pointer */
542 if (die_get_real_type(&type, &type) == NULL) {
543 pr_warning("Failed to get the type of %s.\n", varname);
544 return -ENOENT;
545 }
546 /* Verify it is a data structure */
547 tag = dwarf_tag(&type);
548 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
549 pr_warning("%s is not a data structure nor an union.\n",
550 varname);
551 return -EINVAL;
552 }
553
554 ref = zalloc(sizeof(struct probe_trace_arg_ref));
555 if (ref == NULL)
556 return -ENOMEM;
557 if (*ref_ptr)
558 (*ref_ptr)->next = ref;
559 else
560 *ref_ptr = ref;
561 } else {
562 /* Verify it is a data structure */
563 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
564 pr_warning("%s is not a data structure nor an union.\n",
565 varname);
566 return -EINVAL;
567 }
568 if (field->name[0] == '[') {
569 pr_err("Semantic error: %s is not a pointor"
570 " nor array.\n", varname);
571 return -EINVAL;
572 }
573 if (field->ref) {
574 pr_err("Semantic error: %s must be referred by '.'\n",
575 field->name);
576 return -EINVAL;
577 }
578 if (!ref) {
579 pr_warning("Structure on a register is not "
580 "supported yet.\n");
581 return -ENOTSUP;
582 }
583 }
584
585 if (die_find_member(&type, field->name, die_mem) == NULL) {
586 pr_warning("%s(tyep:%s) has no member %s.\n", varname,
587 dwarf_diename(&type), field->name);
588 return -EINVAL;
589 }
590
591 /* Get the offset of the field */
592 if (tag == DW_TAG_union_type) {
593 offs = 0;
594 } else {
595 ret = die_get_data_member_location(die_mem, &offs);
596 if (ret < 0) {
597 pr_warning("Failed to get the offset of %s.\n",
598 field->name);
599 return ret;
600 }
601 }
602 ref->offset += (long)offs;
603
604 next:
605 /* Converting next field */
606 if (field->next)
607 return convert_variable_fields(die_mem, field->name,
608 field->next, &ref, die_mem);
609 else
610 return 0;
611 }
612
613 /* Show a variables in kprobe event format */
614 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
615 {
616 Dwarf_Die die_mem;
617 int ret;
618
619 pr_debug("Converting variable %s into trace event.\n",
620 dwarf_diename(vr_die));
621
622 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
623 &pf->sp_die, pf->tvar);
624 if (ret == -ENOENT)
625 pr_err("Failed to find the location of %s at this address.\n"
626 " Perhaps, it has been optimized out.\n", pf->pvar->var);
627 else if (ret == -ENOTSUP)
628 pr_err("Sorry, we don't support this variable location yet.\n");
629 else if (pf->pvar->field) {
630 ret = convert_variable_fields(vr_die, pf->pvar->var,
631 pf->pvar->field, &pf->tvar->ref,
632 &die_mem);
633 vr_die = &die_mem;
634 }
635 if (ret == 0)
636 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
637 /* *expr will be cached in libdw. Don't free it. */
638 return ret;
639 }
640
641 /* Find a variable in a scope DIE */
642 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
643 {
644 Dwarf_Die vr_die;
645 char buf[32], *ptr;
646 int ret = 0;
647
648 if (!is_c_varname(pf->pvar->var)) {
649 /* Copy raw parameters */
650 pf->tvar->value = strdup(pf->pvar->var);
651 if (pf->tvar->value == NULL)
652 return -ENOMEM;
653 if (pf->pvar->type) {
654 pf->tvar->type = strdup(pf->pvar->type);
655 if (pf->tvar->type == NULL)
656 return -ENOMEM;
657 }
658 if (pf->pvar->name) {
659 pf->tvar->name = strdup(pf->pvar->name);
660 if (pf->tvar->name == NULL)
661 return -ENOMEM;
662 } else
663 pf->tvar->name = NULL;
664 return 0;
665 }
666
667 if (pf->pvar->name)
668 pf->tvar->name = strdup(pf->pvar->name);
669 else {
670 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
671 if (ret < 0)
672 return ret;
673 ptr = strchr(buf, ':'); /* Change type separator to _ */
674 if (ptr)
675 *ptr = '_';
676 pf->tvar->name = strdup(buf);
677 }
678 if (pf->tvar->name == NULL)
679 return -ENOMEM;
680
681 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
682 /* Search child die for local variables and parameters. */
683 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
684 /* Search again in global variables */
685 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die))
686 ret = -ENOENT;
687 }
688 if (ret >= 0)
689 ret = convert_variable(&vr_die, pf);
690
691 if (ret < 0)
692 pr_warning("Failed to find '%s' in this function.\n",
693 pf->pvar->var);
694 return ret;
695 }
696
697 /* Convert subprogram DIE to trace point */
698 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
699 Dwarf_Addr paddr, bool retprobe,
700 struct probe_trace_point *tp)
701 {
702 Dwarf_Addr eaddr, highaddr;
703 GElf_Sym sym;
704 const char *symbol;
705
706 /* Verify the address is correct */
707 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
708 pr_warning("Failed to get entry address of %s\n",
709 dwarf_diename(sp_die));
710 return -ENOENT;
711 }
712 if (dwarf_highpc(sp_die, &highaddr) != 0) {
713 pr_warning("Failed to get end address of %s\n",
714 dwarf_diename(sp_die));
715 return -ENOENT;
716 }
717 if (paddr > highaddr) {
718 pr_warning("Offset specified is greater than size of %s\n",
719 dwarf_diename(sp_die));
720 return -EINVAL;
721 }
722
723 /* Get an appropriate symbol from symtab */
724 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
725 if (!symbol) {
726 pr_warning("Failed to find symbol at 0x%lx\n",
727 (unsigned long)paddr);
728 return -ENOENT;
729 }
730 tp->offset = (unsigned long)(paddr - sym.st_value);
731 tp->symbol = strdup(symbol);
732 if (!tp->symbol)
733 return -ENOMEM;
734
735 /* Return probe must be on the head of a subprogram */
736 if (retprobe) {
737 if (eaddr != paddr) {
738 pr_warning("Return probe must be on the head of"
739 " a real function.\n");
740 return -EINVAL;
741 }
742 tp->retprobe = true;
743 }
744
745 return 0;
746 }
747
748 /* Call probe_finder callback with scope DIE */
749 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
750 {
751 Dwarf_Attribute fb_attr;
752 size_t nops;
753 int ret;
754
755 if (!sc_die) {
756 pr_err("Caller must pass a scope DIE. Program error.\n");
757 return -EINVAL;
758 }
759
760 /* If not a real subprogram, find a real one */
761 if (!die_is_func_def(sc_die)) {
762 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
763 pr_warning("Failed to find probe point in any "
764 "functions.\n");
765 return -ENOENT;
766 }
767 } else
768 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
769
770 /* Get the frame base attribute/ops from subprogram */
771 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
772 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
773 if (ret <= 0 || nops == 0) {
774 pf->fb_ops = NULL;
775 #if _ELFUTILS_PREREQ(0, 142)
776 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
777 pf->cfi != NULL) {
778 Dwarf_Frame *frame;
779 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
780 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
781 pr_warning("Failed to get call frame on 0x%jx\n",
782 (uintmax_t)pf->addr);
783 return -ENOENT;
784 }
785 #endif
786 }
787
788 /* Call finder's callback handler */
789 ret = pf->callback(sc_die, pf);
790
791 /* *pf->fb_ops will be cached in libdw. Don't free it. */
792 pf->fb_ops = NULL;
793
794 return ret;
795 }
796
797 struct find_scope_param {
798 const char *function;
799 const char *file;
800 int line;
801 int diff;
802 Dwarf_Die *die_mem;
803 bool found;
804 };
805
806 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
807 {
808 struct find_scope_param *fsp = data;
809 const char *file;
810 int lno;
811
812 /* Skip if declared file name does not match */
813 if (fsp->file) {
814 file = dwarf_decl_file(fn_die);
815 if (!file || strcmp(fsp->file, file) != 0)
816 return 0;
817 }
818 /* If the function name is given, that's what user expects */
819 if (fsp->function) {
820 if (die_compare_name(fn_die, fsp->function)) {
821 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
822 fsp->found = true;
823 return 1;
824 }
825 } else {
826 /* With the line number, find the nearest declared DIE */
827 dwarf_decl_line(fn_die, &lno);
828 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
829 /* Keep a candidate and continue */
830 fsp->diff = fsp->line - lno;
831 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
832 fsp->found = true;
833 }
834 }
835 return 0;
836 }
837
838 /* Find an appropriate scope fits to given conditions */
839 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
840 {
841 struct find_scope_param fsp = {
842 .function = pf->pev->point.function,
843 .file = pf->fname,
844 .line = pf->lno,
845 .diff = INT_MAX,
846 .die_mem = die_mem,
847 .found = false,
848 };
849
850 cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
851
852 return fsp.found ? die_mem : NULL;
853 }
854
855 static int probe_point_line_walker(const char *fname, int lineno,
856 Dwarf_Addr addr, void *data)
857 {
858 struct probe_finder *pf = data;
859 Dwarf_Die *sc_die, die_mem;
860 int ret;
861
862 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
863 return 0;
864
865 pf->addr = addr;
866 sc_die = find_best_scope(pf, &die_mem);
867 if (!sc_die) {
868 pr_warning("Failed to find scope of probe point.\n");
869 return -ENOENT;
870 }
871
872 ret = call_probe_finder(sc_die, pf);
873
874 /* Continue if no error, because the line will be in inline function */
875 return ret < 0 ? ret : 0;
876 }
877
878 /* Find probe point from its line number */
879 static int find_probe_point_by_line(struct probe_finder *pf)
880 {
881 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
882 }
883
884 /* Find lines which match lazy pattern */
885 static int find_lazy_match_lines(struct list_head *head,
886 const char *fname, const char *pat)
887 {
888 FILE *fp;
889 char *line = NULL;
890 size_t line_len;
891 ssize_t len;
892 int count = 0, linenum = 1;
893
894 fp = fopen(fname, "r");
895 if (!fp) {
896 pr_warning("Failed to open %s: %s\n", fname, strerror(errno));
897 return -errno;
898 }
899
900 while ((len = getline(&line, &line_len, fp)) > 0) {
901
902 if (line[len - 1] == '\n')
903 line[len - 1] = '\0';
904
905 if (strlazymatch(line, pat)) {
906 line_list__add_line(head, linenum);
907 count++;
908 }
909 linenum++;
910 }
911
912 if (ferror(fp))
913 count = -errno;
914 free(line);
915 fclose(fp);
916
917 if (count == 0)
918 pr_debug("No matched lines found in %s.\n", fname);
919 return count;
920 }
921
922 static int probe_point_lazy_walker(const char *fname, int lineno,
923 Dwarf_Addr addr, void *data)
924 {
925 struct probe_finder *pf = data;
926 Dwarf_Die *sc_die, die_mem;
927 int ret;
928
929 if (!line_list__has_line(&pf->lcache, lineno) ||
930 strtailcmp(fname, pf->fname) != 0)
931 return 0;
932
933 pr_debug("Probe line found: line:%d addr:0x%llx\n",
934 lineno, (unsigned long long)addr);
935 pf->addr = addr;
936 pf->lno = lineno;
937 sc_die = find_best_scope(pf, &die_mem);
938 if (!sc_die) {
939 pr_warning("Failed to find scope of probe point.\n");
940 return -ENOENT;
941 }
942
943 ret = call_probe_finder(sc_die, pf);
944
945 /*
946 * Continue if no error, because the lazy pattern will match
947 * to other lines
948 */
949 return ret < 0 ? ret : 0;
950 }
951
952 /* Find probe points from lazy pattern */
953 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
954 {
955 int ret = 0;
956
957 if (list_empty(&pf->lcache)) {
958 /* Matching lazy line pattern */
959 ret = find_lazy_match_lines(&pf->lcache, pf->fname,
960 pf->pev->point.lazy_line);
961 if (ret <= 0)
962 return ret;
963 }
964
965 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
966 }
967
968 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
969 {
970 struct probe_finder *pf = data;
971 struct perf_probe_point *pp = &pf->pev->point;
972 Dwarf_Addr addr;
973 int ret;
974
975 if (pp->lazy_line)
976 ret = find_probe_point_lazy(in_die, pf);
977 else {
978 /* Get probe address */
979 if (dwarf_entrypc(in_die, &addr) != 0) {
980 pr_warning("Failed to get entry address of %s.\n",
981 dwarf_diename(in_die));
982 return -ENOENT;
983 }
984 pf->addr = addr;
985 pf->addr += pp->offset;
986 pr_debug("found inline addr: 0x%jx\n",
987 (uintmax_t)pf->addr);
988
989 ret = call_probe_finder(in_die, pf);
990 }
991
992 return ret;
993 }
994
995 /* Callback parameter with return value for libdw */
996 struct dwarf_callback_param {
997 void *data;
998 int retval;
999 };
1000
1001 /* Search function from function name */
1002 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
1003 {
1004 struct dwarf_callback_param *param = data;
1005 struct probe_finder *pf = param->data;
1006 struct perf_probe_point *pp = &pf->pev->point;
1007
1008 /* Check tag and diename */
1009 if (!die_is_func_def(sp_die) ||
1010 !die_compare_name(sp_die, pp->function))
1011 return DWARF_CB_OK;
1012
1013 /* Check declared file */
1014 if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
1015 return DWARF_CB_OK;
1016
1017 pf->fname = dwarf_decl_file(sp_die);
1018 if (pp->line) { /* Function relative line */
1019 dwarf_decl_line(sp_die, &pf->lno);
1020 pf->lno += pp->line;
1021 param->retval = find_probe_point_by_line(pf);
1022 } else if (!dwarf_func_inline(sp_die)) {
1023 /* Real function */
1024 if (pp->lazy_line)
1025 param->retval = find_probe_point_lazy(sp_die, pf);
1026 else {
1027 if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
1028 pr_warning("Failed to get entry address of "
1029 "%s.\n", dwarf_diename(sp_die));
1030 param->retval = -ENOENT;
1031 return DWARF_CB_ABORT;
1032 }
1033 pf->addr += pp->offset;
1034 /* TODO: Check the address in this function */
1035 param->retval = call_probe_finder(sp_die, pf);
1036 }
1037 } else
1038 /* Inlined function: search instances */
1039 param->retval = die_walk_instances(sp_die,
1040 probe_point_inline_cb, (void *)pf);
1041
1042 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1043 }
1044
1045 static int find_probe_point_by_func(struct probe_finder *pf)
1046 {
1047 struct dwarf_callback_param _param = {.data = (void *)pf,
1048 .retval = 0};
1049 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1050 return _param.retval;
1051 }
1052
1053 struct pubname_callback_param {
1054 char *function;
1055 char *file;
1056 Dwarf_Die *cu_die;
1057 Dwarf_Die *sp_die;
1058 int found;
1059 };
1060
1061 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1062 {
1063 struct pubname_callback_param *param = data;
1064
1065 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1066 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1067 return DWARF_CB_OK;
1068
1069 if (die_compare_name(param->sp_die, param->function)) {
1070 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1071 return DWARF_CB_OK;
1072
1073 if (param->file &&
1074 strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1075 return DWARF_CB_OK;
1076
1077 param->found = 1;
1078 return DWARF_CB_ABORT;
1079 }
1080 }
1081
1082 return DWARF_CB_OK;
1083 }
1084
1085 /* Find probe points from debuginfo */
1086 static int debuginfo__find_probes(struct debuginfo *self,
1087 struct probe_finder *pf)
1088 {
1089 struct perf_probe_point *pp = &pf->pev->point;
1090 Dwarf_Off off, noff;
1091 size_t cuhl;
1092 Dwarf_Die *diep;
1093 int ret = 0;
1094
1095 #if _ELFUTILS_PREREQ(0, 142)
1096 /* Get the call frame information from this dwarf */
1097 pf->cfi = dwarf_getcfi(self->dbg);
1098 #endif
1099
1100 off = 0;
1101 line_list__init(&pf->lcache);
1102
1103 /* Fastpath: lookup by function name from .debug_pubnames section */
1104 if (pp->function) {
1105 struct pubname_callback_param pubname_param = {
1106 .function = pp->function,
1107 .file = pp->file,
1108 .cu_die = &pf->cu_die,
1109 .sp_die = &pf->sp_die,
1110 .found = 0,
1111 };
1112 struct dwarf_callback_param probe_param = {
1113 .data = pf,
1114 };
1115
1116 dwarf_getpubnames(self->dbg, pubname_search_cb,
1117 &pubname_param, 0);
1118 if (pubname_param.found) {
1119 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1120 if (ret)
1121 goto found;
1122 }
1123 }
1124
1125 /* Loop on CUs (Compilation Unit) */
1126 while (!dwarf_nextcu(self->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1127 /* Get the DIE(Debugging Information Entry) of this CU */
1128 diep = dwarf_offdie(self->dbg, off + cuhl, &pf->cu_die);
1129 if (!diep)
1130 continue;
1131
1132 /* Check if target file is included. */
1133 if (pp->file)
1134 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1135 else
1136 pf->fname = NULL;
1137
1138 if (!pp->file || pf->fname) {
1139 if (pp->function)
1140 ret = find_probe_point_by_func(pf);
1141 else if (pp->lazy_line)
1142 ret = find_probe_point_lazy(NULL, pf);
1143 else {
1144 pf->lno = pp->line;
1145 ret = find_probe_point_by_line(pf);
1146 }
1147 if (ret < 0)
1148 break;
1149 }
1150 off = noff;
1151 }
1152
1153 found:
1154 line_list__free(&pf->lcache);
1155
1156 return ret;
1157 }
1158
1159 struct local_vars_finder {
1160 struct probe_finder *pf;
1161 struct perf_probe_arg *args;
1162 int max_args;
1163 int nargs;
1164 int ret;
1165 };
1166
1167 /* Collect available variables in this scope */
1168 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1169 {
1170 struct local_vars_finder *vf = data;
1171 struct probe_finder *pf = vf->pf;
1172 int tag;
1173
1174 tag = dwarf_tag(die_mem);
1175 if (tag == DW_TAG_formal_parameter ||
1176 tag == DW_TAG_variable) {
1177 if (convert_variable_location(die_mem, vf->pf->addr,
1178 vf->pf->fb_ops, &pf->sp_die,
1179 NULL) == 0) {
1180 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1181 if (vf->args[vf->nargs].var == NULL) {
1182 vf->ret = -ENOMEM;
1183 return DIE_FIND_CB_END;
1184 }
1185 pr_debug(" %s", vf->args[vf->nargs].var);
1186 vf->nargs++;
1187 }
1188 }
1189
1190 if (dwarf_haspc(die_mem, vf->pf->addr))
1191 return DIE_FIND_CB_CONTINUE;
1192 else
1193 return DIE_FIND_CB_SIBLING;
1194 }
1195
1196 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1197 struct perf_probe_arg *args)
1198 {
1199 Dwarf_Die die_mem;
1200 int i;
1201 int n = 0;
1202 struct local_vars_finder vf = {.pf = pf, .args = args,
1203 .max_args = MAX_PROBE_ARGS, .ret = 0};
1204
1205 for (i = 0; i < pf->pev->nargs; i++) {
1206 /* var never be NULL */
1207 if (strcmp(pf->pev->args[i].var, "$vars") == 0) {
1208 pr_debug("Expanding $vars into:");
1209 vf.nargs = n;
1210 /* Special local variables */
1211 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1212 &die_mem);
1213 pr_debug(" (%d)\n", vf.nargs - n);
1214 if (vf.ret < 0)
1215 return vf.ret;
1216 n = vf.nargs;
1217 } else {
1218 /* Copy normal argument */
1219 args[n] = pf->pev->args[i];
1220 n++;
1221 }
1222 }
1223 return n;
1224 }
1225
1226 /* Add a found probe point into trace event list */
1227 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1228 {
1229 struct trace_event_finder *tf =
1230 container_of(pf, struct trace_event_finder, pf);
1231 struct probe_trace_event *tev;
1232 struct perf_probe_arg *args;
1233 int ret, i;
1234
1235 /* Check number of tevs */
1236 if (tf->ntevs == tf->max_tevs) {
1237 pr_warning("Too many( > %d) probe point found.\n",
1238 tf->max_tevs);
1239 return -ERANGE;
1240 }
1241 tev = &tf->tevs[tf->ntevs++];
1242
1243 /* Trace point should be converted from subprogram DIE */
1244 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1245 pf->pev->point.retprobe, &tev->point);
1246 if (ret < 0)
1247 return ret;
1248
1249 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1250 tev->point.offset);
1251
1252 /* Expand special probe argument if exist */
1253 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1254 if (args == NULL)
1255 return -ENOMEM;
1256
1257 ret = expand_probe_args(sc_die, pf, args);
1258 if (ret < 0)
1259 goto end;
1260
1261 tev->nargs = ret;
1262 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1263 if (tev->args == NULL) {
1264 ret = -ENOMEM;
1265 goto end;
1266 }
1267
1268 /* Find each argument */
1269 for (i = 0; i < tev->nargs; i++) {
1270 pf->pvar = &args[i];
1271 pf->tvar = &tev->args[i];
1272 /* Variable should be found from scope DIE */
1273 ret = find_variable(sc_die, pf);
1274 if (ret != 0)
1275 break;
1276 }
1277
1278 end:
1279 free(args);
1280 return ret;
1281 }
1282
1283 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1284 int debuginfo__find_trace_events(struct debuginfo *self,
1285 struct perf_probe_event *pev,
1286 struct probe_trace_event **tevs, int max_tevs)
1287 {
1288 struct trace_event_finder tf = {
1289 .pf = {.pev = pev, .callback = add_probe_trace_event},
1290 .mod = self->mod, .max_tevs = max_tevs};
1291 int ret;
1292
1293 /* Allocate result tevs array */
1294 *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
1295 if (*tevs == NULL)
1296 return -ENOMEM;
1297
1298 tf.tevs = *tevs;
1299 tf.ntevs = 0;
1300
1301 ret = debuginfo__find_probes(self, &tf.pf);
1302 if (ret < 0) {
1303 free(*tevs);
1304 *tevs = NULL;
1305 return ret;
1306 }
1307
1308 return (ret < 0) ? ret : tf.ntevs;
1309 }
1310
1311 #define MAX_VAR_LEN 64
1312
1313 /* Collect available variables in this scope */
1314 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1315 {
1316 struct available_var_finder *af = data;
1317 struct variable_list *vl;
1318 char buf[MAX_VAR_LEN];
1319 int tag, ret;
1320
1321 vl = &af->vls[af->nvls - 1];
1322
1323 tag = dwarf_tag(die_mem);
1324 if (tag == DW_TAG_formal_parameter ||
1325 tag == DW_TAG_variable) {
1326 ret = convert_variable_location(die_mem, af->pf.addr,
1327 af->pf.fb_ops, &af->pf.sp_die,
1328 NULL);
1329 if (ret == 0) {
1330 ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1331 pr_debug2("Add new var: %s\n", buf);
1332 if (ret > 0)
1333 strlist__add(vl->vars, buf);
1334 }
1335 }
1336
1337 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1338 return DIE_FIND_CB_CONTINUE;
1339 else
1340 return DIE_FIND_CB_SIBLING;
1341 }
1342
1343 /* Add a found vars into available variables list */
1344 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1345 {
1346 struct available_var_finder *af =
1347 container_of(pf, struct available_var_finder, pf);
1348 struct variable_list *vl;
1349 Dwarf_Die die_mem;
1350 int ret;
1351
1352 /* Check number of tevs */
1353 if (af->nvls == af->max_vls) {
1354 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1355 return -ERANGE;
1356 }
1357 vl = &af->vls[af->nvls++];
1358
1359 /* Trace point should be converted from subprogram DIE */
1360 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1361 pf->pev->point.retprobe, &vl->point);
1362 if (ret < 0)
1363 return ret;
1364
1365 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1366 vl->point.offset);
1367
1368 /* Find local variables */
1369 vl->vars = strlist__new(true, NULL);
1370 if (vl->vars == NULL)
1371 return -ENOMEM;
1372 af->child = true;
1373 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1374
1375 /* Find external variables */
1376 if (!af->externs)
1377 goto out;
1378 /* Don't need to search child DIE for externs. */
1379 af->child = false;
1380 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1381
1382 out:
1383 if (strlist__empty(vl->vars)) {
1384 strlist__delete(vl->vars);
1385 vl->vars = NULL;
1386 }
1387
1388 return ret;
1389 }
1390
1391 /* Find available variables at given probe point */
1392 int debuginfo__find_available_vars_at(struct debuginfo *self,
1393 struct perf_probe_event *pev,
1394 struct variable_list **vls,
1395 int max_vls, bool externs)
1396 {
1397 struct available_var_finder af = {
1398 .pf = {.pev = pev, .callback = add_available_vars},
1399 .mod = self->mod,
1400 .max_vls = max_vls, .externs = externs};
1401 int ret;
1402
1403 /* Allocate result vls array */
1404 *vls = zalloc(sizeof(struct variable_list) * max_vls);
1405 if (*vls == NULL)
1406 return -ENOMEM;
1407
1408 af.vls = *vls;
1409 af.nvls = 0;
1410
1411 ret = debuginfo__find_probes(self, &af.pf);
1412 if (ret < 0) {
1413 /* Free vlist for error */
1414 while (af.nvls--) {
1415 if (af.vls[af.nvls].point.symbol)
1416 free(af.vls[af.nvls].point.symbol);
1417 if (af.vls[af.nvls].vars)
1418 strlist__delete(af.vls[af.nvls].vars);
1419 }
1420 free(af.vls);
1421 *vls = NULL;
1422 return ret;
1423 }
1424
1425 return (ret < 0) ? ret : af.nvls;
1426 }
1427
1428 /* Reverse search */
1429 int debuginfo__find_probe_point(struct debuginfo *self, unsigned long addr,
1430 struct perf_probe_point *ppt)
1431 {
1432 Dwarf_Die cudie, spdie, indie;
1433 Dwarf_Addr _addr = 0, baseaddr = 0;
1434 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1435 int baseline = 0, lineno = 0, ret = 0;
1436
1437 /* Adjust address with bias */
1438 addr += self->bias;
1439
1440 /* Find cu die */
1441 if (!dwarf_addrdie(self->dbg, (Dwarf_Addr)addr - self->bias, &cudie)) {
1442 pr_warning("Failed to find debug information for address %lx\n",
1443 addr);
1444 ret = -EINVAL;
1445 goto end;
1446 }
1447
1448 /* Find a corresponding line (filename and lineno) */
1449 cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1450 /* Don't care whether it failed or not */
1451
1452 /* Find a corresponding function (name, baseline and baseaddr) */
1453 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1454 /* Get function entry information */
1455 func = basefunc = dwarf_diename(&spdie);
1456 if (!func ||
1457 dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1458 dwarf_decl_line(&spdie, &baseline) != 0) {
1459 lineno = 0;
1460 goto post;
1461 }
1462
1463 if (addr == (unsigned long)baseaddr) {
1464 /* Function entry - Relative line number is 0 */
1465 lineno = baseline;
1466 fname = dwarf_decl_file(&spdie);
1467 goto post;
1468 }
1469
1470 /* Track down the inline functions step by step */
1471 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1472 &indie)) {
1473 /* There is an inline function */
1474 if (dwarf_entrypc(&indie, &_addr) == 0 &&
1475 _addr == addr) {
1476 /*
1477 * addr is at an inline function entry.
1478 * In this case, lineno should be the call-site
1479 * line number. (overwrite lineinfo)
1480 */
1481 lineno = die_get_call_lineno(&indie);
1482 fname = die_get_call_file(&indie);
1483 break;
1484 } else {
1485 /*
1486 * addr is in an inline function body.
1487 * Since lineno points one of the lines
1488 * of the inline function, baseline should
1489 * be the entry line of the inline function.
1490 */
1491 tmp = dwarf_diename(&indie);
1492 if (!tmp ||
1493 dwarf_decl_line(&indie, &baseline) != 0)
1494 break;
1495 func = tmp;
1496 spdie = indie;
1497 }
1498 }
1499 /* Verify the lineno and baseline are in a same file */
1500 tmp = dwarf_decl_file(&spdie);
1501 if (!tmp || strcmp(tmp, fname) != 0)
1502 lineno = 0;
1503 }
1504
1505 post:
1506 /* Make a relative line number or an offset */
1507 if (lineno)
1508 ppt->line = lineno - baseline;
1509 else if (basefunc) {
1510 ppt->offset = addr - (unsigned long)baseaddr;
1511 func = basefunc;
1512 }
1513
1514 /* Duplicate strings */
1515 if (func) {
1516 ppt->function = strdup(func);
1517 if (ppt->function == NULL) {
1518 ret = -ENOMEM;
1519 goto end;
1520 }
1521 }
1522 if (fname) {
1523 ppt->file = strdup(fname);
1524 if (ppt->file == NULL) {
1525 if (ppt->function) {
1526 free(ppt->function);
1527 ppt->function = NULL;
1528 }
1529 ret = -ENOMEM;
1530 goto end;
1531 }
1532 }
1533 end:
1534 if (ret == 0 && (fname || func))
1535 ret = 1; /* Found a point */
1536 return ret;
1537 }
1538
1539 /* Add a line and store the src path */
1540 static int line_range_add_line(const char *src, unsigned int lineno,
1541 struct line_range *lr)
1542 {
1543 /* Copy source path */
1544 if (!lr->path) {
1545 lr->path = strdup(src);
1546 if (lr->path == NULL)
1547 return -ENOMEM;
1548 }
1549 return line_list__add_line(&lr->line_list, lineno);
1550 }
1551
1552 static int line_range_walk_cb(const char *fname, int lineno,
1553 Dwarf_Addr addr __maybe_unused,
1554 void *data)
1555 {
1556 struct line_finder *lf = data;
1557
1558 if ((strtailcmp(fname, lf->fname) != 0) ||
1559 (lf->lno_s > lineno || lf->lno_e < lineno))
1560 return 0;
1561
1562 if (line_range_add_line(fname, lineno, lf->lr) < 0)
1563 return -EINVAL;
1564
1565 return 0;
1566 }
1567
1568 /* Find line range from its line number */
1569 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1570 {
1571 int ret;
1572
1573 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1574
1575 /* Update status */
1576 if (ret >= 0)
1577 if (!list_empty(&lf->lr->line_list))
1578 ret = lf->found = 1;
1579 else
1580 ret = 0; /* Lines are not found */
1581 else {
1582 free(lf->lr->path);
1583 lf->lr->path = NULL;
1584 }
1585 return ret;
1586 }
1587
1588 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1589 {
1590 find_line_range_by_line(in_die, data);
1591
1592 /*
1593 * We have to check all instances of inlined function, because
1594 * some execution paths can be optimized out depends on the
1595 * function argument of instances
1596 */
1597 return 0;
1598 }
1599
1600 /* Search function definition from function name */
1601 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1602 {
1603 struct dwarf_callback_param *param = data;
1604 struct line_finder *lf = param->data;
1605 struct line_range *lr = lf->lr;
1606
1607 /* Check declared file */
1608 if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1609 return DWARF_CB_OK;
1610
1611 if (die_is_func_def(sp_die) &&
1612 die_compare_name(sp_die, lr->function)) {
1613 lf->fname = dwarf_decl_file(sp_die);
1614 dwarf_decl_line(sp_die, &lr->offset);
1615 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1616 lf->lno_s = lr->offset + lr->start;
1617 if (lf->lno_s < 0) /* Overflow */
1618 lf->lno_s = INT_MAX;
1619 lf->lno_e = lr->offset + lr->end;
1620 if (lf->lno_e < 0) /* Overflow */
1621 lf->lno_e = INT_MAX;
1622 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1623 lr->start = lf->lno_s;
1624 lr->end = lf->lno_e;
1625 if (dwarf_func_inline(sp_die))
1626 param->retval = die_walk_instances(sp_die,
1627 line_range_inline_cb, lf);
1628 else
1629 param->retval = find_line_range_by_line(sp_die, lf);
1630 return DWARF_CB_ABORT;
1631 }
1632 return DWARF_CB_OK;
1633 }
1634
1635 static int find_line_range_by_func(struct line_finder *lf)
1636 {
1637 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1638 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1639 return param.retval;
1640 }
1641
1642 int debuginfo__find_line_range(struct debuginfo *self, struct line_range *lr)
1643 {
1644 struct line_finder lf = {.lr = lr, .found = 0};
1645 int ret = 0;
1646 Dwarf_Off off = 0, noff;
1647 size_t cuhl;
1648 Dwarf_Die *diep;
1649 const char *comp_dir;
1650
1651 /* Fastpath: lookup by function name from .debug_pubnames section */
1652 if (lr->function) {
1653 struct pubname_callback_param pubname_param = {
1654 .function = lr->function, .file = lr->file,
1655 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1656 struct dwarf_callback_param line_range_param = {
1657 .data = (void *)&lf, .retval = 0};
1658
1659 dwarf_getpubnames(self->dbg, pubname_search_cb,
1660 &pubname_param, 0);
1661 if (pubname_param.found) {
1662 line_range_search_cb(&lf.sp_die, &line_range_param);
1663 if (lf.found)
1664 goto found;
1665 }
1666 }
1667
1668 /* Loop on CUs (Compilation Unit) */
1669 while (!lf.found && ret >= 0) {
1670 if (dwarf_nextcu(self->dbg, off, &noff, &cuhl,
1671 NULL, NULL, NULL) != 0)
1672 break;
1673
1674 /* Get the DIE(Debugging Information Entry) of this CU */
1675 diep = dwarf_offdie(self->dbg, off + cuhl, &lf.cu_die);
1676 if (!diep)
1677 continue;
1678
1679 /* Check if target file is included. */
1680 if (lr->file)
1681 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1682 else
1683 lf.fname = 0;
1684
1685 if (!lr->file || lf.fname) {
1686 if (lr->function)
1687 ret = find_line_range_by_func(&lf);
1688 else {
1689 lf.lno_s = lr->start;
1690 lf.lno_e = lr->end;
1691 ret = find_line_range_by_line(NULL, &lf);
1692 }
1693 }
1694 off = noff;
1695 }
1696
1697 found:
1698 /* Store comp_dir */
1699 if (lf.found) {
1700 comp_dir = cu_get_comp_dir(&lf.cu_die);
1701 if (comp_dir) {
1702 lr->comp_dir = strdup(comp_dir);
1703 if (!lr->comp_dir)
1704 ret = -ENOMEM;
1705 }
1706 }
1707
1708 pr_debug("path: %s\n", lr->path);
1709 return (ret < 0) ? ret : lf.found;
1710 }
1711
Linux kernel - Deliverables
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