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Merge tag 'trace-printf-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace...
[drm/drm-misc.git] / tools / perf / util / probe-finder.c
blob7f2ee0cb43ca488ece89853fd723dd8540b19f6a
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 "debuginfo.h"
27 #include "intlist.h"
28 #include "strbuf.h"
29 #include "strlist.h"
30 #include "symbol.h"
31 #include "probe-finder.h"
32 #include "probe-file.h"
33 #include "string2.h"
34
35 /* Kprobe tracer basic type is up to u64 */
36 #define MAX_BASIC_TYPE_BITS 64
37
38 /*
39 * Probe finder related functions
40 */
41
42 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
43 {
44 struct probe_trace_arg_ref *ref;
45 ref = zalloc(sizeof(struct probe_trace_arg_ref));
46 if (ref != NULL)
47 ref->offset = offs;
48 return ref;
49 }
50
51 /*
52 * Convert a location into trace_arg.
53 * If tvar == NULL, this just checks variable can be converted.
54 * If fentry == true and vr_die is a parameter, do heuristic search
55 * for the location fuzzed by function entry mcount.
56 */
57 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
58 Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
59 const struct probe_finder *pf,
60 struct probe_trace_arg *tvar)
61 {
62 Dwarf_Attribute attr;
63 Dwarf_Addr tmp = 0;
64 Dwarf_Op *op;
65 size_t nops;
66 unsigned int regn;
67 Dwarf_Word offs = 0;
68 bool ref = false;
69 const char *regs;
70 int ret, ret2 = 0;
71
72 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
73 goto static_var;
74
75 /* Constant value */
76 if (dwarf_attr(vr_die, DW_AT_const_value, &attr) &&
77 immediate_value_is_supported()) {
78 Dwarf_Sword snum;
79
80 if (!tvar)
81 return 0;
82
83 dwarf_formsdata(&attr, &snum);
84 ret = asprintf(&tvar->value, "\\%ld", (long)snum);
85
86 return ret < 0 ? -ENOMEM : 0;
87 }
88
89 /* TODO: handle more than 1 exprs */
90 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
91 return -EINVAL; /* Broken DIE ? */
92 if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
93 ret = dwarf_entrypc(sp_die, &tmp);
94 if (ret)
95 return -ENOENT;
96
97 if (probe_conf.show_location_range &&
98 (dwarf_tag(vr_die) == DW_TAG_variable)) {
99 ret2 = -ERANGE;
100 } else if (addr != tmp ||
101 dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
102 return -ENOENT;
103 }
104
105 ret = dwarf_highpc(sp_die, &tmp);
106 if (ret)
107 return -ENOENT;
108 /*
109 * This is fuzzed by fentry mcount. We try to find the
110 * parameter location at the earliest address.
111 */
112 for (addr += 1; addr <= tmp; addr++) {
113 if (dwarf_getlocation_addr(&attr, addr, &op,
114 &nops, 1) > 0)
115 goto found;
116 }
117 return -ENOENT;
118 }
119 found:
120 if (nops == 0)
121 /* TODO: Support const_value */
122 return -ENOENT;
123
124 if (op->atom == DW_OP_addr) {
125 static_var:
126 if (!tvar)
127 return ret2;
128 /* Static variables on memory (not stack), make @varname */
129 ret = strlen(dwarf_diename(vr_die));
130 tvar->value = zalloc(ret + 2);
131 if (tvar->value == NULL)
132 return -ENOMEM;
133 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
134 tvar->ref = alloc_trace_arg_ref((long)offs);
135 if (tvar->ref == NULL)
136 return -ENOMEM;
137 return ret2;
138 }
139
140 /* If this is based on frame buffer, set the offset */
141 if (op->atom == DW_OP_fbreg) {
142 if (fb_ops == NULL)
143 return -ENOTSUP;
144 ref = true;
145 offs = op->number;
146 op = &fb_ops[0];
147 }
148
149 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
150 regn = op->atom - DW_OP_breg0;
151 offs += op->number;
152 ref = true;
153 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
154 regn = op->atom - DW_OP_reg0;
155 } else if (op->atom == DW_OP_bregx) {
156 regn = op->number;
157 offs += op->number2;
158 ref = true;
159 } else if (op->atom == DW_OP_regx) {
160 regn = op->number;
161 } else {
162 pr_debug("DW_OP %x is not supported.\n", op->atom);
163 return -ENOTSUP;
164 }
165
166 if (!tvar)
167 return ret2;
168
169 regs = get_dwarf_regstr(regn, pf->e_machine, pf->e_flags);
170 if (!regs) {
171 /* This should be a bug in DWARF or this tool */
172 pr_warning("Mapping for the register number %u "
173 "missing on this architecture.\n", regn);
174 return -ENOTSUP;
175 }
176
177 tvar->value = strdup(regs);
178 if (tvar->value == NULL)
179 return -ENOMEM;
180
181 if (ref) {
182 tvar->ref = alloc_trace_arg_ref((long)offs);
183 if (tvar->ref == NULL)
184 return -ENOMEM;
185 }
186 return ret2;
187 }
188
189 static int convert_variable_type(Dwarf_Die *vr_die,
190 struct probe_trace_arg *tvar,
191 const char *cast, bool user_access)
192 {
193 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
194 Dwarf_Die type;
195 char buf[16];
196 char sbuf[STRERR_BUFSIZE];
197 int bsize, boffs, total;
198 int ret;
199 char prefix;
200
201 /* TODO: check all types */
202 if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "ustring") &&
203 strcmp(cast, "x") != 0 &&
204 strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
205 /* Non string type is OK */
206 /* and respect signedness/hexadecimal cast */
207 tvar->type = strdup(cast);
208 return (tvar->type == NULL) ? -ENOMEM : 0;
209 }
210
211 bsize = dwarf_bitsize(vr_die);
212 if (bsize > 0) {
213 /* This is a bitfield */
214 boffs = dwarf_bitoffset(vr_die);
215 total = dwarf_bytesize(vr_die);
216 if (boffs < 0 || total < 0)
217 return -ENOENT;
218 ret = snprintf(buf, 16, "b%d@%d/%d", bsize, boffs,
219 BYTES_TO_BITS(total));
220 goto formatted;
221 }
222
223 if (die_get_real_type(vr_die, &type) == NULL) {
224 pr_warning("Failed to get a type information of %s.\n",
225 dwarf_diename(vr_die));
226 return -ENOENT;
227 }
228
229 pr_debug("%s type is %s.\n",
230 dwarf_diename(vr_die), dwarf_diename(&type));
231
232 if (cast && (!strcmp(cast, "string") || !strcmp(cast, "ustring"))) {
233 /* String type */
234 ret = dwarf_tag(&type);
235 if (ret != DW_TAG_pointer_type &&
236 ret != DW_TAG_array_type) {
237 pr_warning("Failed to cast into string: "
238 "%s(%s) is not a pointer nor array.\n",
239 dwarf_diename(vr_die), dwarf_diename(&type));
240 return -EINVAL;
241 }
242 if (die_get_real_type(&type, &type) == NULL) {
243 pr_warning("Failed to get a type"
244 " information.\n");
245 return -ENOENT;
246 }
247 if (ret == DW_TAG_pointer_type) {
248 while (*ref_ptr)
249 ref_ptr = &(*ref_ptr)->next;
250 /* Add new reference with offset +0 */
251 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
252 if (*ref_ptr == NULL) {
253 pr_warning("Out of memory error\n");
254 return -ENOMEM;
255 }
256 (*ref_ptr)->user_access = user_access;
257 }
258 if (!die_compare_name(&type, "char") &&
259 !die_compare_name(&type, "unsigned char")) {
260 pr_warning("Failed to cast into string: "
261 "%s is not (unsigned) char *.\n",
262 dwarf_diename(vr_die));
263 return -EINVAL;
264 }
265 tvar->type = strdup(cast);
266 return (tvar->type == NULL) ? -ENOMEM : 0;
267 }
268
269 if (cast && (strcmp(cast, "u") == 0))
270 prefix = 'u';
271 else if (cast && (strcmp(cast, "s") == 0))
272 prefix = 's';
273 else if (cast && (strcmp(cast, "x") == 0) &&
274 probe_type_is_available(PROBE_TYPE_X))
275 prefix = 'x';
276 else
277 prefix = die_is_signed_type(&type) ? 's' :
278 probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
279
280 ret = dwarf_bytesize(&type);
281 if (ret <= 0)
282 /* No size ... try to use default type */
283 return 0;
284 ret = BYTES_TO_BITS(ret);
285
286 /* Check the bitwidth */
287 if (ret > MAX_BASIC_TYPE_BITS) {
288 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
289 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
290 ret = MAX_BASIC_TYPE_BITS;
291 }
292 ret = snprintf(buf, 16, "%c%d", prefix, ret);
293
294 formatted:
295 if (ret < 0 || ret >= 16) {
296 if (ret >= 16)
297 ret = -E2BIG;
298 pr_warning("Failed to convert variable type: %s\n",
299 str_error_r(-ret, sbuf, sizeof(sbuf)));
300 return ret;
301 }
302 tvar->type = strdup(buf);
303 if (tvar->type == NULL)
304 return -ENOMEM;
305 return 0;
306 }
307
308 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
309 struct perf_probe_arg_field *field,
310 struct probe_trace_arg_ref **ref_ptr,
311 Dwarf_Die *die_mem, bool user_access)
312 {
313 struct probe_trace_arg_ref *ref = *ref_ptr;
314 Dwarf_Die type;
315 Dwarf_Word offs;
316 int ret, tag;
317
318 pr_debug("converting %s in %s\n", field->name, varname);
319 if (die_get_real_type(vr_die, &type) == NULL) {
320 pr_warning("Failed to get the type of %s.\n", varname);
321 return -ENOENT;
322 }
323 pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type),
324 (unsigned)dwarf_dieoffset(&type));
325 tag = dwarf_tag(&type);
326
327 if (field->name[0] == '[' &&
328 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
329 /* Save original type for next field or type */
330 memcpy(die_mem, &type, sizeof(*die_mem));
331 /* Get the type of this array */
332 if (die_get_real_type(&type, &type) == NULL) {
333 pr_warning("Failed to get the type of %s.\n", varname);
334 return -ENOENT;
335 }
336 pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type),
337 (unsigned)dwarf_dieoffset(&type));
338 if (tag == DW_TAG_pointer_type) {
339 ref = zalloc(sizeof(struct probe_trace_arg_ref));
340 if (ref == NULL)
341 return -ENOMEM;
342 if (*ref_ptr)
343 (*ref_ptr)->next = ref;
344 else
345 *ref_ptr = ref;
346 }
347 ref->offset += dwarf_bytesize(&type) * field->index;
348 ref->user_access = user_access;
349 goto next;
350 } else if (tag == DW_TAG_pointer_type) {
351 /* Check the pointer and dereference */
352 if (!field->ref) {
353 pr_err("Semantic error: %s must be referred by '->'\n",
354 field->name);
355 return -EINVAL;
356 }
357 /* Get the type pointed by this pointer */
358 if (die_get_real_type(&type, &type) == NULL) {
359 pr_warning("Failed to get the type of %s.\n", varname);
360 return -ENOENT;
361 }
362 /* Verify it is a data structure */
363 tag = dwarf_tag(&type);
364 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
365 pr_warning("%s is not a data structure nor a union.\n",
366 varname);
367 return -EINVAL;
368 }
369
370 ref = zalloc(sizeof(struct probe_trace_arg_ref));
371 if (ref == NULL)
372 return -ENOMEM;
373 if (*ref_ptr)
374 (*ref_ptr)->next = ref;
375 else
376 *ref_ptr = ref;
377 } else {
378 /* Verify it is a data structure */
379 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
380 pr_warning("%s is not a data structure nor a union.\n",
381 varname);
382 return -EINVAL;
383 }
384 if (field->name[0] == '[') {
385 pr_err("Semantic error: %s is not a pointer"
386 " nor array.\n", varname);
387 return -EINVAL;
388 }
389 /* While processing unnamed field, we don't care about this */
390 if (field->ref && dwarf_diename(vr_die)) {
391 pr_err("Semantic error: %s must be referred by '.'\n",
392 field->name);
393 return -EINVAL;
394 }
395 if (!ref) {
396 pr_warning("Structure on a register is not "
397 "supported yet.\n");
398 return -ENOTSUP;
399 }
400 }
401
402 if (die_find_member(&type, field->name, die_mem) == NULL) {
403 pr_warning("%s(type:%s) has no member %s.\n", varname,
404 dwarf_diename(&type), field->name);
405 return -EINVAL;
406 }
407
408 /* Get the offset of the field */
409 if (tag == DW_TAG_union_type) {
410 offs = 0;
411 } else {
412 ret = die_get_data_member_location(die_mem, &offs);
413 if (ret < 0) {
414 pr_warning("Failed to get the offset of %s.\n",
415 field->name);
416 return ret;
417 }
418 }
419 ref->offset += (long)offs;
420 ref->user_access = user_access;
421
422 /* If this member is unnamed, we need to reuse this field */
423 if (!dwarf_diename(die_mem))
424 return convert_variable_fields(die_mem, varname, field,
425 &ref, die_mem, user_access);
426
427 next:
428 /* Converting next field */
429 if (field->next)
430 return convert_variable_fields(die_mem, field->name,
431 field->next, &ref, die_mem, user_access);
432 else
433 return 0;
434 }
435
436 static void print_var_not_found(const char *varname)
437 {
438 pr_err("Failed to find the location of the '%s' variable at this address.\n"
439 " Perhaps it has been optimized out.\n"
440 " Use -V with the --range option to show '%s' location range.\n",
441 varname, varname);
442 }
443
444 /* Show a variables in kprobe event format */
445 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
446 {
447 Dwarf_Die die_mem;
448 int ret;
449
450 pr_debug("Converting variable %s into trace event.\n",
451 dwarf_diename(vr_die));
452
453 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
454 &pf->sp_die, pf, pf->tvar);
455 if (ret == -ENOENT && pf->skip_empty_arg)
456 /* This can be found in other place. skip it */
457 return 0;
458 if (ret == -ENOENT || ret == -EINVAL) {
459 print_var_not_found(pf->pvar->var);
460 } else if (ret == -ENOTSUP)
461 pr_err("Sorry, we don't support this variable location yet.\n");
462 else if (ret == 0 && pf->pvar->field) {
463 ret = convert_variable_fields(vr_die, pf->pvar->var,
464 pf->pvar->field, &pf->tvar->ref,
465 &die_mem, pf->pvar->user_access);
466 vr_die = &die_mem;
467 }
468 if (ret == 0)
469 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type,
470 pf->pvar->user_access);
471 /* *expr will be cached in libdw. Don't free it. */
472 return ret;
473 }
474
475 /* Find a variable in a scope DIE */
476 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
477 {
478 Dwarf_Die vr_die;
479 char *buf, *ptr;
480 int ret = 0;
481
482 /* Copy raw parameters */
483 if (!is_c_varname(pf->pvar->var))
484 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
485
486 if (pf->pvar->name)
487 pf->tvar->name = strdup(pf->pvar->name);
488 else {
489 buf = synthesize_perf_probe_arg(pf->pvar);
490 if (!buf)
491 return -ENOMEM;
492 ptr = strchr(buf, ':'); /* Change type separator to _ */
493 if (ptr)
494 *ptr = '_';
495 pf->tvar->name = buf;
496 }
497 if (pf->tvar->name == NULL)
498 return -ENOMEM;
499
500 pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
501 /* Search child die for local variables and parameters. */
502 if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
503 /* Search again in global variables */
504 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
505 0, &vr_die)) {
506 if (pf->skip_empty_arg)
507 return 0;
508 pr_warning("Failed to find '%s' in this function.\n",
509 pf->pvar->var);
510 ret = -ENOENT;
511 }
512 }
513 if (ret >= 0)
514 ret = convert_variable(&vr_die, pf);
515
516 return ret;
517 }
518
519 /* Convert subprogram DIE to trace point */
520 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
521 Dwarf_Addr paddr, bool retprobe,
522 const char *function,
523 struct probe_trace_point *tp)
524 {
525 Dwarf_Addr eaddr;
526 GElf_Sym sym;
527 const char *symbol;
528
529 /* Verify the address is correct */
530 if (!dwarf_haspc(sp_die, paddr)) {
531 pr_warning("Specified offset is out of %s\n",
532 dwarf_diename(sp_die));
533 return -EINVAL;
534 }
535
536 if (dwarf_entrypc(sp_die, &eaddr) == 0) {
537 /* If the DIE has entrypc, use it. */
538 symbol = dwarf_diename(sp_die);
539 } else {
540 /* Try to get actual symbol name and address from symtab */
541 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
542 eaddr = sym.st_value;
543 }
544 if (!symbol) {
545 pr_warning("Failed to find symbol at 0x%lx\n",
546 (unsigned long)paddr);
547 return -ENOENT;
548 }
549
550 tp->offset = (unsigned long)(paddr - eaddr);
551 tp->address = paddr;
552 tp->symbol = strdup(symbol);
553 if (!tp->symbol)
554 return -ENOMEM;
555
556 /* Return probe must be on the head of a subprogram */
557 if (retprobe) {
558 if (eaddr != paddr) {
559 pr_warning("Failed to find \"%s%%return\",\n"
560 " because %s is an inlined function and"
561 " has no return point.\n", function,
562 function);
563 return -EINVAL;
564 }
565 tp->retprobe = true;
566 }
567
568 return 0;
569 }
570
571 /* Call probe_finder callback with scope DIE */
572 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
573 {
574 Dwarf_Attribute fb_attr;
575 Dwarf_Frame *frame = NULL;
576 size_t nops;
577 int ret;
578
579 if (!sc_die) {
580 pr_err("Caller must pass a scope DIE. Program error.\n");
581 return -EINVAL;
582 }
583
584 /* If not a real subprogram, find a real one */
585 if (!die_is_func_def(sc_die)) {
586 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
587 if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
588 pr_warning("Ignoring tail call from %s\n",
589 dwarf_diename(&pf->sp_die));
590 return 0;
591 } else {
592 pr_warning("Failed to find probe point in any "
593 "functions.\n");
594 return -ENOENT;
595 }
596 }
597 } else
598 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
599
600 /* Get the frame base attribute/ops from subprogram */
601 dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
602 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
603 if (ret <= 0 || nops == 0) {
604 pf->fb_ops = NULL;
605 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
606 (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
607 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
608 (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
609 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
610 pr_warning("Failed to get call frame on 0x%jx\n",
611 (uintmax_t)pf->addr);
612 free(frame);
613 return -ENOENT;
614 }
615 }
616
617 /* Call finder's callback handler */
618 ret = pf->callback(sc_die, pf);
619
620 /* Since *pf->fb_ops can be a part of frame. we should free it here. */
621 free(frame);
622 pf->fb_ops = NULL;
623
624 return ret;
625 }
626
627 struct find_scope_param {
628 const char *function;
629 const char *file;
630 int line;
631 int diff;
632 Dwarf_Die *die_mem;
633 bool found;
634 };
635
636 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
637 {
638 struct find_scope_param *fsp = data;
639 const char *file;
640 int lno;
641
642 /* Skip if declared file name does not match */
643 if (fsp->file) {
644 file = die_get_decl_file(fn_die);
645 if (!file || strcmp(fsp->file, file) != 0)
646 return 0;
647 }
648 /* If the function name is given, that's what user expects */
649 if (fsp->function) {
650 if (die_match_name(fn_die, fsp->function)) {
651 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
652 fsp->found = true;
653 return 1;
654 }
655 } else {
656 /* With the line number, find the nearest declared DIE */
657 dwarf_decl_line(fn_die, &lno);
658 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
659 /* Keep a candidate and continue */
660 fsp->diff = fsp->line - lno;
661 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
662 fsp->found = true;
663 }
664 }
665 return 0;
666 }
667
668 /* Return innermost DIE */
669 static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data)
670 {
671 struct find_scope_param *fsp = data;
672
673 memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
674 fsp->found = true;
675 return 1;
676 }
677
678 /* Find an appropriate scope fits to given conditions */
679 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
680 {
681 struct find_scope_param fsp = {
682 .function = pf->pev->point.function,
683 .file = pf->fname,
684 .line = pf->lno,
685 .diff = INT_MAX,
686 .die_mem = die_mem,
687 .found = false,
688 };
689 int ret;
690
691 ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb,
692 &fsp);
693 if (!ret && !fsp.found)
694 cu_walk_functions_at(&pf->cu_die, pf->addr,
695 find_inner_scope_cb, &fsp);
696
697 return fsp.found ? die_mem : NULL;
698 }
699
700 static int verify_representive_line(struct probe_finder *pf, const char *fname,
701 int lineno, Dwarf_Addr addr)
702 {
703 const char *__fname, *__func = NULL;
704 Dwarf_Die die_mem;
705 int __lineno;
706
707 /* Verify line number and address by reverse search */
708 if (cu_find_lineinfo(&pf->cu_die, addr, &__fname, &__lineno) < 0)
709 return 0;
710
711 pr_debug2("Reversed line: %s:%d\n", __fname, __lineno);
712 if (strcmp(fname, __fname) || lineno == __lineno)
713 return 0;
714
715 pr_warning("This line is sharing the address with other lines.\n");
716
717 if (pf->pev->point.function) {
718 /* Find best match function name and lines */
719 pf->addr = addr;
720 if (find_best_scope(pf, &die_mem)
721 && die_match_name(&die_mem, pf->pev->point.function)
722 && dwarf_decl_line(&die_mem, &lineno) == 0) {
723 __func = dwarf_diename(&die_mem);
724 __lineno -= lineno;
725 }
726 }
727 pr_warning("Please try to probe at %s:%d instead.\n",
728 __func ? : __fname, __lineno);
729
730 return -ENOENT;
731 }
732
733 static int probe_point_line_walker(const char *fname, int lineno,
734 Dwarf_Addr addr, void *data)
735 {
736 struct probe_finder *pf = data;
737 Dwarf_Die *sc_die, die_mem;
738 int ret;
739
740 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
741 return 0;
742
743 if (verify_representive_line(pf, fname, lineno, addr))
744 return -ENOENT;
745
746 pf->addr = addr;
747 sc_die = find_best_scope(pf, &die_mem);
748 if (!sc_die) {
749 pr_warning("Failed to find scope of probe point.\n");
750 return -ENOENT;
751 }
752
753 ret = call_probe_finder(sc_die, pf);
754
755 /* Continue if no error, because the line will be in inline function */
756 return ret < 0 ? ret : 0;
757 }
758
759 /* Find probe point from its line number */
760 static int find_probe_point_by_line(struct probe_finder *pf)
761 {
762 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
763 }
764
765 /* Find lines which match lazy pattern */
766 static int find_lazy_match_lines(struct intlist *list,
767 const char *fname, const char *pat)
768 {
769 FILE *fp;
770 char *line = NULL;
771 size_t line_len;
772 ssize_t len;
773 int count = 0, linenum = 1;
774 char sbuf[STRERR_BUFSIZE];
775
776 fp = fopen(fname, "r");
777 if (!fp) {
778 pr_warning("Failed to open %s: %s\n", fname,
779 str_error_r(errno, sbuf, sizeof(sbuf)));
780 return -errno;
781 }
782
783 while ((len = getline(&line, &line_len, fp)) > 0) {
784
785 if (line[len - 1] == '\n')
786 line[len - 1] = '\0';
787
788 if (strlazymatch(line, pat)) {
789 intlist__add(list, linenum);
790 count++;
791 }
792 linenum++;
793 }
794
795 if (ferror(fp))
796 count = -errno;
797 free(line);
798 fclose(fp);
799
800 if (count == 0)
801 pr_debug("No matched lines found in %s.\n", fname);
802 return count;
803 }
804
805 static int probe_point_lazy_walker(const char *fname, int lineno,
806 Dwarf_Addr addr, void *data)
807 {
808 struct probe_finder *pf = data;
809 Dwarf_Die *sc_die, die_mem;
810 int ret;
811
812 if (!intlist__has_entry(pf->lcache, lineno) ||
813 strtailcmp(fname, pf->fname) != 0)
814 return 0;
815
816 pr_debug("Probe line found: line:%d addr:0x%llx\n",
817 lineno, (unsigned long long)addr);
818 pf->addr = addr;
819 pf->lno = lineno;
820 sc_die = find_best_scope(pf, &die_mem);
821 if (!sc_die) {
822 pr_warning("Failed to find scope of probe point.\n");
823 return -ENOENT;
824 }
825
826 ret = call_probe_finder(sc_die, pf);
827
828 /*
829 * Continue if no error, because the lazy pattern will match
830 * to other lines
831 */
832 return ret < 0 ? ret : 0;
833 }
834
835 /* Find probe points from lazy pattern */
836 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
837 {
838 struct build_id bid;
839 char sbuild_id[SBUILD_ID_SIZE] = "";
840 int ret = 0;
841 char *fpath;
842
843 if (intlist__empty(pf->lcache)) {
844 const char *comp_dir;
845
846 comp_dir = cu_get_comp_dir(&pf->cu_die);
847 if (pf->dbg->build_id) {
848 build_id__init(&bid, pf->dbg->build_id, BUILD_ID_SIZE);
849 build_id__sprintf(&bid, sbuild_id);
850 }
851 ret = find_source_path(pf->fname, sbuild_id, comp_dir, &fpath);
852 if (ret < 0) {
853 pr_warning("Failed to find source file path.\n");
854 return ret;
855 }
856
857 /* Matching lazy line pattern */
858 ret = find_lazy_match_lines(pf->lcache, fpath,
859 pf->pev->point.lazy_line);
860 free(fpath);
861 if (ret <= 0)
862 return ret;
863 }
864
865 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
866 }
867
868 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
869 {
870 struct perf_probe_point *pp = &pf->pev->point;
871
872 /* Not uprobe? */
873 if (!pf->pev->uprobes)
874 return;
875
876 /* Compiled with optimization? */
877 if (die_is_optimized_target(&pf->cu_die))
878 return;
879
880 /* Don't know entrypc? */
881 if (!pf->addr)
882 return;
883
884 /* Only FUNC and FUNC@SRC are eligible. */
885 if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
886 pp->offset || pp->abs_address)
887 return;
888
889 /* Not interested in func parameter? */
890 if (!perf_probe_with_var(pf->pev))
891 return;
892
893 pr_info("Target program is compiled without optimization. Skipping prologue.\n"
894 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
895 pf->addr);
896
897 die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
898 }
899
900 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
901 {
902 struct probe_finder *pf = data;
903 struct perf_probe_point *pp = &pf->pev->point;
904 Dwarf_Addr addr;
905 int ret;
906
907 if (pp->lazy_line)
908 ret = find_probe_point_lazy(in_die, pf);
909 else {
910 /* Get probe address */
911 if (die_entrypc(in_die, &addr) != 0) {
912 pr_warning("Failed to get entry address of %s.\n",
913 dwarf_diename(in_die));
914 return -ENOENT;
915 }
916 if (addr == 0) {
917 pr_debug("%s has no valid entry address. skipped.\n",
918 dwarf_diename(in_die));
919 return -ENOENT;
920 }
921 pf->addr = addr;
922 pf->addr += pp->offset;
923 pr_debug("found inline addr: 0x%jx\n",
924 (uintmax_t)pf->addr);
925
926 ret = call_probe_finder(in_die, pf);
927 }
928
929 return ret;
930 }
931
932 /* Callback parameter with return value for libdw */
933 struct dwarf_callback_param {
934 void *data;
935 int retval;
936 };
937
938 /* Search function from function name */
939 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
940 {
941 struct dwarf_callback_param *param = data;
942 struct probe_finder *pf = param->data;
943 struct perf_probe_point *pp = &pf->pev->point;
944 const char *fname;
945
946 /* Check tag and diename */
947 if (!die_is_func_def(sp_die) ||
948 !die_match_name(sp_die, pp->function))
949 return DWARF_CB_OK;
950
951 /* Check declared file */
952 fname = die_get_decl_file(sp_die);
953 if (!fname) {
954 pr_warning("A function DIE doesn't have decl_line. Maybe broken DWARF?\n");
955 return DWARF_CB_OK;
956 }
957 if (pp->file && fname && strtailcmp(pp->file, fname))
958 return DWARF_CB_OK;
959
960 pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
961 (unsigned long)dwarf_dieoffset(sp_die));
962 pf->fname = fname;
963 if (pp->line) { /* Function relative line */
964 dwarf_decl_line(sp_die, &pf->lno);
965 pf->lno += pp->line;
966 param->retval = find_probe_point_by_line(pf);
967 } else if (die_is_func_instance(sp_die)) {
968 /* Instances always have the entry address */
969 die_entrypc(sp_die, &pf->addr);
970 /* But in some case the entry address is 0 */
971 if (pf->addr == 0) {
972 pr_debug("%s has no entry PC. Skipped\n",
973 dwarf_diename(sp_die));
974 param->retval = 0;
975 /* Real function */
976 } else if (pp->lazy_line)
977 param->retval = find_probe_point_lazy(sp_die, pf);
978 else {
979 skip_prologue(sp_die, pf);
980 pf->addr += pp->offset;
981 /* TODO: Check the address in this function */
982 param->retval = call_probe_finder(sp_die, pf);
983 }
984 } else if (!probe_conf.no_inlines) {
985 /* Inlined function: search instances */
986 param->retval = die_walk_instances(sp_die,
987 probe_point_inline_cb, (void *)pf);
988 /* This could be a non-existed inline definition */
989 if (param->retval == -ENOENT)
990 param->retval = 0;
991 }
992
993 /* We need to find other candidates */
994 if (strisglob(pp->function) && param->retval >= 0) {
995 param->retval = 0; /* We have to clear the result */
996 return DWARF_CB_OK;
997 }
998
999 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1000 }
1001
1002 static int find_probe_point_by_func(struct probe_finder *pf)
1003 {
1004 struct dwarf_callback_param _param = {.data = (void *)pf,
1005 .retval = 0};
1006 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1007 return _param.retval;
1008 }
1009
1010 struct pubname_callback_param {
1011 char *function;
1012 char *file;
1013 Dwarf_Die *cu_die;
1014 Dwarf_Die *sp_die;
1015 int found;
1016 };
1017
1018 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1019 {
1020 struct pubname_callback_param *param = data;
1021 const char *fname;
1022
1023 if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1024 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1025 return DWARF_CB_OK;
1026
1027 if (die_match_name(param->sp_die, param->function)) {
1028 if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1029 return DWARF_CB_OK;
1030
1031 if (param->file) {
1032 fname = die_get_decl_file(param->sp_die);
1033 if (!fname || strtailcmp(param->file, fname))
1034 return DWARF_CB_OK;
1035 }
1036
1037 param->found = 1;
1038 return DWARF_CB_ABORT;
1039 }
1040 }
1041
1042 return DWARF_CB_OK;
1043 }
1044
1045 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1046 struct probe_finder *pf)
1047 {
1048 struct perf_probe_point *pp = &pf->pev->point;
1049 Dwarf_Off off, noff;
1050 size_t cuhl;
1051 Dwarf_Die *diep;
1052 int ret = 0;
1053
1054 off = 0;
1055 pf->lcache = intlist__new(NULL);
1056 if (!pf->lcache)
1057 return -ENOMEM;
1058
1059 /* Fastpath: lookup by function name from .debug_pubnames section */
1060 if (pp->function && !strisglob(pp->function)) {
1061 struct pubname_callback_param pubname_param = {
1062 .function = pp->function,
1063 .file = pp->file,
1064 .cu_die = &pf->cu_die,
1065 .sp_die = &pf->sp_die,
1066 .found = 0,
1067 };
1068 struct dwarf_callback_param probe_param = {
1069 .data = pf,
1070 };
1071
1072 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1073 &pubname_param, 0);
1074 if (pubname_param.found) {
1075 ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1076 if (ret)
1077 goto found;
1078 }
1079 }
1080
1081 /* Loop on CUs (Compilation Unit) */
1082 while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1083 /* Get the DIE(Debugging Information Entry) of this CU */
1084 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1085 if (!diep) {
1086 off = noff;
1087 continue;
1088 }
1089
1090 /* Check if target file is included. */
1091 if (pp->file)
1092 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1093 else
1094 pf->fname = NULL;
1095
1096 if (!pp->file || pf->fname) {
1097 if (pp->function)
1098 ret = find_probe_point_by_func(pf);
1099 else if (pp->lazy_line)
1100 ret = find_probe_point_lazy(&pf->cu_die, pf);
1101 else {
1102 pf->lno = pp->line;
1103 ret = find_probe_point_by_line(pf);
1104 }
1105 if (ret < 0)
1106 break;
1107 }
1108 off = noff;
1109 }
1110
1111 found:
1112 intlist__delete(pf->lcache);
1113 pf->lcache = NULL;
1114
1115 return ret;
1116 }
1117
1118 /* Find probe points from debuginfo */
1119 static int debuginfo__find_probes(struct debuginfo *dbg,
1120 struct probe_finder *pf)
1121 {
1122 int ret = 0;
1123 Elf *elf;
1124 GElf_Ehdr ehdr;
1125
1126 if (pf->cfi_eh || pf->cfi_dbg)
1127 return debuginfo__find_probe_location(dbg, pf);
1128
1129 /* Get the call frame information from this dwarf */
1130 elf = dwarf_getelf(dbg->dbg);
1131 if (elf == NULL)
1132 return -EINVAL;
1133
1134 if (gelf_getehdr(elf, &ehdr) == NULL)
1135 return -EINVAL;
1136
1137 pf->e_machine = ehdr.e_machine;
1138 pf->e_flags = ehdr.e_flags;
1139
1140 do {
1141 GElf_Shdr shdr;
1142
1143 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1144 shdr.sh_type == SHT_PROGBITS)
1145 pf->cfi_eh = dwarf_getcfi_elf(elf);
1146
1147 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1148 } while (0);
1149
1150 ret = debuginfo__find_probe_location(dbg, pf);
1151 return ret;
1152 }
1153
1154 struct local_vars_finder {
1155 struct probe_finder *pf;
1156 struct perf_probe_arg *args;
1157 bool vars;
1158 int max_args;
1159 int nargs;
1160 int ret;
1161 };
1162
1163 /* Collect available variables in this scope */
1164 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1165 {
1166 struct local_vars_finder *vf = data;
1167 struct probe_finder *pf = vf->pf;
1168 int tag;
1169
1170 tag = dwarf_tag(die_mem);
1171 if (tag == DW_TAG_formal_parameter ||
1172 (tag == DW_TAG_variable && vf->vars)) {
1173 if (convert_variable_location(die_mem, vf->pf->addr,
1174 vf->pf->fb_ops, &pf->sp_die,
1175 pf, /*tvar=*/NULL) == 0) {
1176 vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1177 if (vf->args[vf->nargs].var == NULL) {
1178 vf->ret = -ENOMEM;
1179 return DIE_FIND_CB_END;
1180 }
1181 pr_debug(" %s", vf->args[vf->nargs].var);
1182 vf->nargs++;
1183 }
1184 }
1185
1186 if (dwarf_haspc(die_mem, vf->pf->addr))
1187 return DIE_FIND_CB_CONTINUE;
1188 else
1189 return DIE_FIND_CB_SIBLING;
1190 }
1191
1192 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1193 struct perf_probe_arg *args)
1194 {
1195 Dwarf_Die die_mem;
1196 int i;
1197 int n = 0;
1198 struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1199 .max_args = MAX_PROBE_ARGS, .ret = 0};
1200
1201 for (i = 0; i < pf->pev->nargs; i++) {
1202 /* var never be NULL */
1203 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1204 vf.vars = true;
1205 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1206 /* Copy normal argument */
1207 args[n] = pf->pev->args[i];
1208 n++;
1209 continue;
1210 }
1211 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1212 vf.nargs = n;
1213 /* Special local variables */
1214 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1215 &die_mem);
1216 pr_debug(" (%d)\n", vf.nargs - n);
1217 if (vf.ret < 0)
1218 return vf.ret;
1219 n = vf.nargs;
1220 }
1221 return n;
1222 }
1223
1224 static bool trace_event_finder_overlap(struct trace_event_finder *tf)
1225 {
1226 int i;
1227
1228 for (i = 0; i < tf->ntevs; i++) {
1229 if (tf->pf.addr == tf->tevs[i].point.address)
1230 return true;
1231 }
1232 return false;
1233 }
1234
1235 /* Add a found probe point into trace event list */
1236 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1237 {
1238 struct trace_event_finder *tf =
1239 container_of(pf, struct trace_event_finder, pf);
1240 struct perf_probe_point *pp = &pf->pev->point;
1241 struct probe_trace_event *tev;
1242 struct perf_probe_arg *args = NULL;
1243 int ret, i;
1244
1245 /*
1246 * For some reason (e.g. different column assigned to same address)
1247 * This callback can be called with the address which already passed.
1248 * Ignore it first.
1249 */
1250 if (trace_event_finder_overlap(tf))
1251 return 0;
1252
1253 /* Check number of tevs */
1254 if (tf->ntevs == tf->max_tevs) {
1255 pr_warning("Too many( > %d) probe point found.\n",
1256 tf->max_tevs);
1257 return -ERANGE;
1258 }
1259 tev = &tf->tevs[tf->ntevs++];
1260
1261 /* Trace point should be converted from subprogram DIE */
1262 ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1263 pp->retprobe, pp->function, &tev->point);
1264 if (ret < 0)
1265 goto end;
1266
1267 tev->point.realname = strdup(dwarf_diename(sc_die));
1268 if (!tev->point.realname) {
1269 ret = -ENOMEM;
1270 goto end;
1271 }
1272
1273 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1274 tev->point.offset);
1275
1276 /* Expand special probe argument if exist */
1277 args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1278 if (args == NULL) {
1279 ret = -ENOMEM;
1280 goto end;
1281 }
1282
1283 ret = expand_probe_args(sc_die, pf, args);
1284 if (ret < 0)
1285 goto end;
1286
1287 tev->nargs = ret;
1288 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1289 if (tev->args == NULL) {
1290 ret = -ENOMEM;
1291 goto end;
1292 }
1293
1294 /* Find each argument */
1295 for (i = 0; i < tev->nargs; i++) {
1296 pf->pvar = &args[i];
1297 pf->tvar = &tev->args[i];
1298 /* Variable should be found from scope DIE */
1299 ret = find_variable(sc_die, pf);
1300 if (ret != 0)
1301 break;
1302 }
1303
1304 end:
1305 if (ret) {
1306 clear_probe_trace_event(tev);
1307 tf->ntevs--;
1308 }
1309 free(args);
1310 return ret;
1311 }
1312
1313 static int fill_empty_trace_arg(struct perf_probe_event *pev,
1314 struct probe_trace_event *tevs, int ntevs)
1315 {
1316 char **valp;
1317 char *type;
1318 int i, j, ret;
1319
1320 if (!ntevs)
1321 return -ENOENT;
1322
1323 for (i = 0; i < pev->nargs; i++) {
1324 type = NULL;
1325 for (j = 0; j < ntevs; j++) {
1326 if (tevs[j].args[i].value) {
1327 type = tevs[j].args[i].type;
1328 break;
1329 }
1330 }
1331 if (j == ntevs) {
1332 print_var_not_found(pev->args[i].var);
1333 return -ENOENT;
1334 }
1335 for (j = 0; j < ntevs; j++) {
1336 valp = &tevs[j].args[i].value;
1337 if (*valp)
1338 continue;
1339
1340 ret = asprintf(valp, "\\%lx", probe_conf.magic_num);
1341 if (ret < 0)
1342 return -ENOMEM;
1343 /* Note that type can be NULL */
1344 if (type) {
1345 tevs[j].args[i].type = strdup(type);
1346 if (!tevs[j].args[i].type)
1347 return -ENOMEM;
1348 }
1349 }
1350 }
1351 return 0;
1352 }
1353
1354 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1355 int debuginfo__find_trace_events(struct debuginfo *dbg,
1356 struct perf_probe_event *pev,
1357 struct probe_trace_event **tevs)
1358 {
1359 struct trace_event_finder tf = {
1360 .pf = {.pev = pev, .dbg = dbg, .callback = add_probe_trace_event},
1361 .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1362 int ret, i;
1363
1364 /* Allocate result tevs array */
1365 *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1366 if (*tevs == NULL)
1367 return -ENOMEM;
1368
1369 tf.tevs = *tevs;
1370 tf.ntevs = 0;
1371
1372 if (pev->nargs != 0 && immediate_value_is_supported())
1373 tf.pf.skip_empty_arg = true;
1374
1375 ret = debuginfo__find_probes(dbg, &tf.pf);
1376 if (ret >= 0 && tf.pf.skip_empty_arg)
1377 ret = fill_empty_trace_arg(pev, tf.tevs, tf.ntevs);
1378
1379 dwarf_cfi_end(tf.pf.cfi_eh);
1380
1381 if (ret < 0 || tf.ntevs == 0) {
1382 for (i = 0; i < tf.ntevs; i++)
1383 clear_probe_trace_event(&tf.tevs[i]);
1384 zfree(tevs);
1385 return ret;
1386 }
1387
1388 return (ret < 0) ? ret : tf.ntevs;
1389 }
1390
1391 /* Collect available variables in this scope */
1392 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1393 {
1394 struct available_var_finder *af = data;
1395 struct variable_list *vl;
1396 struct strbuf buf = STRBUF_INIT;
1397 int tag, ret;
1398
1399 vl = &af->vls[af->nvls - 1];
1400
1401 tag = dwarf_tag(die_mem);
1402 if (tag == DW_TAG_formal_parameter ||
1403 tag == DW_TAG_variable) {
1404 ret = convert_variable_location(die_mem, af->pf.addr,
1405 af->pf.fb_ops, &af->pf.sp_die,
1406 &af->pf, /*tvar=*/NULL);
1407 if (ret == 0 || ret == -ERANGE) {
1408 int ret2;
1409 bool externs = !af->child;
1410
1411 if (strbuf_init(&buf, 64) < 0)
1412 goto error;
1413
1414 if (probe_conf.show_location_range) {
1415 if (!externs)
1416 ret2 = strbuf_add(&buf,
1417 ret ? "[INV]\t" : "[VAL]\t", 6);
1418 else
1419 ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1420 if (ret2)
1421 goto error;
1422 }
1423
1424 ret2 = die_get_varname(die_mem, &buf);
1425
1426 if (!ret2 && probe_conf.show_location_range &&
1427 !externs) {
1428 if (strbuf_addch(&buf, '\t') < 0)
1429 goto error;
1430 ret2 = die_get_var_range(&af->pf.sp_die,
1431 die_mem, &buf);
1432 }
1433
1434 pr_debug("Add new var: %s\n", buf.buf);
1435 if (ret2 == 0) {
1436 strlist__add(vl->vars,
1437 strbuf_detach(&buf, NULL));
1438 }
1439 strbuf_release(&buf);
1440 }
1441 }
1442
1443 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1444 return DIE_FIND_CB_CONTINUE;
1445 else
1446 return DIE_FIND_CB_SIBLING;
1447 error:
1448 strbuf_release(&buf);
1449 pr_debug("Error in strbuf\n");
1450 return DIE_FIND_CB_END;
1451 }
1452
1453 static bool available_var_finder_overlap(struct available_var_finder *af)
1454 {
1455 int i;
1456
1457 for (i = 0; i < af->nvls; i++) {
1458 if (af->pf.addr == af->vls[i].point.address)
1459 return true;
1460 }
1461 return false;
1462
1463 }
1464
1465 /* Add a found vars into available variables list */
1466 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1467 {
1468 struct available_var_finder *af =
1469 container_of(pf, struct available_var_finder, pf);
1470 struct perf_probe_point *pp = &pf->pev->point;
1471 struct variable_list *vl;
1472 Dwarf_Die die_mem;
1473 int ret;
1474
1475 /*
1476 * For some reason (e.g. different column assigned to same address),
1477 * this callback can be called with the address which already passed.
1478 * Ignore it first.
1479 */
1480 if (available_var_finder_overlap(af))
1481 return 0;
1482
1483 /* Check number of tevs */
1484 if (af->nvls == af->max_vls) {
1485 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1486 return -ERANGE;
1487 }
1488 vl = &af->vls[af->nvls++];
1489
1490 /* Trace point should be converted from subprogram DIE */
1491 ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1492 pp->retprobe, pp->function, &vl->point);
1493 if (ret < 0)
1494 return ret;
1495
1496 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1497 vl->point.offset);
1498
1499 /* Find local variables */
1500 vl->vars = strlist__new(NULL, NULL);
1501 if (vl->vars == NULL)
1502 return -ENOMEM;
1503 af->child = true;
1504 die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1505
1506 /* Find external variables */
1507 if (!probe_conf.show_ext_vars)
1508 goto out;
1509 /* Don't need to search child DIE for external vars. */
1510 af->child = false;
1511 die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1512
1513 out:
1514 if (strlist__empty(vl->vars)) {
1515 strlist__delete(vl->vars);
1516 vl->vars = NULL;
1517 }
1518
1519 return ret;
1520 }
1521
1522 /*
1523 * Find available variables at given probe point
1524 * Return the number of found probe points. Return 0 if there is no
1525 * matched probe point. Return <0 if an error occurs.
1526 */
1527 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1528 struct perf_probe_event *pev,
1529 struct variable_list **vls)
1530 {
1531 struct available_var_finder af = {
1532 .pf = {.pev = pev, .dbg = dbg, .callback = add_available_vars},
1533 .mod = dbg->mod,
1534 .max_vls = probe_conf.max_probes};
1535 int ret;
1536
1537 /* Allocate result vls array */
1538 *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1539 if (*vls == NULL)
1540 return -ENOMEM;
1541
1542 af.vls = *vls;
1543 af.nvls = 0;
1544
1545 ret = debuginfo__find_probes(dbg, &af.pf);
1546 if (ret < 0) {
1547 /* Free vlist for error */
1548 while (af.nvls--) {
1549 zfree(&af.vls[af.nvls].point.symbol);
1550 strlist__delete(af.vls[af.nvls].vars);
1551 }
1552 zfree(vls);
1553 return ret;
1554 }
1555
1556 return (ret < 0) ? ret : af.nvls;
1557 }
1558
1559 /* Reverse search */
1560 int debuginfo__find_probe_point(struct debuginfo *dbg, u64 addr,
1561 struct perf_probe_point *ppt)
1562 {
1563 Dwarf_Die cudie, spdie, indie;
1564 Dwarf_Addr _addr = 0, baseaddr = 0;
1565 const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1566 int baseline = 0, lineno = 0, ret = 0;
1567
1568 /* We always need to relocate the address for aranges */
1569 if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1570 addr += baseaddr;
1571 /* Find cu die */
1572 if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1573 pr_warning("Failed to find debug information for address %#" PRIx64 "\n",
1574 addr);
1575 ret = -EINVAL;
1576 goto end;
1577 }
1578
1579 /* Find a corresponding line (filename and lineno) */
1580 cu_find_lineinfo(&cudie, (Dwarf_Addr)addr, &fname, &lineno);
1581 /* Don't care whether it failed or not */
1582
1583 /* Find a corresponding function (name, baseline and baseaddr) */
1584 if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1585 /*
1586 * Get function entry information.
1587 *
1588 * As described in the document DWARF Debugging Information
1589 * Format Version 5, section 2.22 Linkage Names, "mangled names,
1590 * are used in various ways, ... to distinguish multiple
1591 * entities that have the same name".
1592 *
1593 * Firstly try to get distinct linkage name, if fail then
1594 * rollback to get associated name in DIE.
1595 */
1596 func = basefunc = die_get_linkage_name(&spdie);
1597 if (!func)
1598 func = basefunc = dwarf_diename(&spdie);
1599
1600 if (!func ||
1601 die_entrypc(&spdie, &baseaddr) != 0 ||
1602 dwarf_decl_line(&spdie, &baseline) != 0) {
1603 lineno = 0;
1604 goto post;
1605 }
1606
1607 fname = die_get_decl_file(&spdie);
1608 if (addr == baseaddr) {
1609 /* Function entry - Relative line number is 0 */
1610 lineno = baseline;
1611 goto post;
1612 }
1613
1614 /* Track down the inline functions step by step */
1615 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1616 &indie)) {
1617 /* There is an inline function */
1618 if (die_entrypc(&indie, &_addr) == 0 &&
1619 _addr == addr) {
1620 /*
1621 * addr is at an inline function entry.
1622 * In this case, lineno should be the call-site
1623 * line number. (overwrite lineinfo)
1624 */
1625 lineno = die_get_call_lineno(&indie);
1626 fname = die_get_call_file(&indie);
1627 break;
1628 } else {
1629 /*
1630 * addr is in an inline function body.
1631 * Since lineno points one of the lines
1632 * of the inline function, baseline should
1633 * be the entry line of the inline function.
1634 */
1635 tmp = dwarf_diename(&indie);
1636 if (!tmp ||
1637 dwarf_decl_line(&indie, &baseline) != 0)
1638 break;
1639 func = tmp;
1640 spdie = indie;
1641 }
1642 }
1643 /* Verify the lineno and baseline are in a same file */
1644 tmp = die_get_decl_file(&spdie);
1645 if (!tmp || (fname && strcmp(tmp, fname) != 0))
1646 lineno = 0;
1647 }
1648
1649 post:
1650 /* Make a relative line number or an offset */
1651 if (lineno)
1652 ppt->line = lineno - baseline;
1653 else if (basefunc) {
1654 ppt->offset = addr - baseaddr;
1655 func = basefunc;
1656 }
1657
1658 /* Duplicate strings */
1659 if (func) {
1660 ppt->function = strdup(func);
1661 if (ppt->function == NULL) {
1662 ret = -ENOMEM;
1663 goto end;
1664 }
1665 }
1666 if (fname) {
1667 ppt->file = strdup(fname);
1668 if (ppt->file == NULL) {
1669 zfree(&ppt->function);
1670 ret = -ENOMEM;
1671 goto end;
1672 }
1673 }
1674 end:
1675 if (ret == 0 && (fname || func))
1676 ret = 1; /* Found a point */
1677 return ret;
1678 }
1679
1680 /* Add a line and store the src path */
1681 static int line_range_add_line(const char *src, unsigned int lineno,
1682 struct line_range *lr)
1683 {
1684 /* Copy source path */
1685 if (!lr->path) {
1686 lr->path = strdup(src);
1687 if (lr->path == NULL)
1688 return -ENOMEM;
1689 }
1690 return intlist__add(lr->line_list, lineno);
1691 }
1692
1693 static int line_range_walk_cb(const char *fname, int lineno,
1694 Dwarf_Addr addr, void *data)
1695 {
1696 struct line_finder *lf = data;
1697 const char *__fname;
1698 int __lineno;
1699 int err;
1700
1701 if ((strtailcmp(fname, lf->fname) != 0) ||
1702 (lf->lno_s > lineno || lf->lno_e < lineno))
1703 return 0;
1704
1705 /* Make sure this line can be reversible */
1706 if (cu_find_lineinfo(&lf->cu_die, addr, &__fname, &__lineno) > 0
1707 && (lineno != __lineno || strcmp(fname, __fname)))
1708 return 0;
1709
1710 err = line_range_add_line(fname, lineno, lf->lr);
1711 if (err < 0 && err != -EEXIST)
1712 return err;
1713
1714 return 0;
1715 }
1716
1717 /* Find line range from its line number */
1718 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1719 {
1720 int ret;
1721
1722 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1723
1724 /* Update status */
1725 if (ret >= 0)
1726 if (!intlist__empty(lf->lr->line_list))
1727 ret = lf->found = 1;
1728 else
1729 ret = 0; /* Lines are not found */
1730 else {
1731 zfree(&lf->lr->path);
1732 }
1733 return ret;
1734 }
1735
1736 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1737 {
1738 int ret = find_line_range_by_line(in_die, data);
1739
1740 /*
1741 * We have to check all instances of inlined function, because
1742 * some execution paths can be optimized out depends on the
1743 * function argument of instances. However, if an error occurs,
1744 * it should be handled by the caller.
1745 */
1746 return ret < 0 ? ret : 0;
1747 }
1748
1749 /* Search function definition from function name */
1750 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1751 {
1752 struct dwarf_callback_param *param = data;
1753 struct line_finder *lf = param->data;
1754 struct line_range *lr = lf->lr;
1755 const char *fname;
1756
1757 /* Check declared file */
1758 if (lr->file) {
1759 fname = die_get_decl_file(sp_die);
1760 if (!fname || strtailcmp(lr->file, fname))
1761 return DWARF_CB_OK;
1762 }
1763
1764 if (die_match_name(sp_die, lr->function) && die_is_func_def(sp_die)) {
1765 lf->fname = die_get_decl_file(sp_die);
1766 dwarf_decl_line(sp_die, &lr->offset);
1767 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1768 lf->lno_s = lr->offset + lr->start;
1769 if (lf->lno_s < 0) /* Overflow */
1770 lf->lno_s = INT_MAX;
1771 lf->lno_e = lr->offset + lr->end;
1772 if (lf->lno_e < 0) /* Overflow */
1773 lf->lno_e = INT_MAX;
1774 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1775 lr->start = lf->lno_s;
1776 lr->end = lf->lno_e;
1777 if (!die_is_func_instance(sp_die))
1778 param->retval = die_walk_instances(sp_die,
1779 line_range_inline_cb, lf);
1780 else
1781 param->retval = find_line_range_by_line(sp_die, lf);
1782 return DWARF_CB_ABORT;
1783 }
1784 return DWARF_CB_OK;
1785 }
1786
1787 static int find_line_range_by_func(struct line_finder *lf)
1788 {
1789 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1790 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1791 return param.retval;
1792 }
1793
1794 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1795 {
1796 struct line_finder lf = {.lr = lr, .found = 0};
1797 int ret = 0;
1798 Dwarf_Off off = 0, noff;
1799 size_t cuhl;
1800 Dwarf_Die *diep;
1801 const char *comp_dir;
1802
1803 /* Fastpath: lookup by function name from .debug_pubnames section */
1804 if (lr->function) {
1805 struct pubname_callback_param pubname_param = {
1806 .function = lr->function, .file = lr->file,
1807 .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1808 struct dwarf_callback_param line_range_param = {
1809 .data = (void *)&lf, .retval = 0};
1810
1811 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1812 &pubname_param, 0);
1813 if (pubname_param.found) {
1814 line_range_search_cb(&lf.sp_die, &line_range_param);
1815 if (lf.found)
1816 goto found;
1817 }
1818 }
1819
1820 /* Loop on CUs (Compilation Unit) */
1821 while (!lf.found && ret >= 0) {
1822 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1823 NULL, NULL, NULL) != 0)
1824 break;
1825
1826 /* Get the DIE(Debugging Information Entry) of this CU */
1827 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1828 if (!diep) {
1829 off = noff;
1830 continue;
1831 }
1832
1833 /* Check if target file is included. */
1834 if (lr->file)
1835 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1836 else
1837 lf.fname = 0;
1838
1839 if (!lr->file || lf.fname) {
1840 if (lr->function)
1841 ret = find_line_range_by_func(&lf);
1842 else {
1843 lf.lno_s = lr->start;
1844 lf.lno_e = lr->end;
1845 ret = find_line_range_by_line(NULL, &lf);
1846 }
1847 }
1848 off = noff;
1849 }
1850
1851 found:
1852 /* Store comp_dir */
1853 if (lf.found) {
1854 comp_dir = cu_get_comp_dir(&lf.cu_die);
1855 if (comp_dir) {
1856 lr->comp_dir = strdup(comp_dir);
1857 if (!lr->comp_dir)
1858 ret = -ENOMEM;
1859 }
1860 }
1861
1862 pr_debug("path: %s\n", lr->path);
1863 return (ret < 0) ? ret : lf.found;
1864 }
1865
1866 /*
1867 * Find a src file from a DWARF tag path. Prepend optional source path prefix
1868 * and chop off leading directories that do not exist. Result is passed back as
1869 * a newly allocated path on success.
1870 * Return 0 if file was found and readable, -errno otherwise.
1871 */
1872 int find_source_path(const char *raw_path, const char *sbuild_id,
1873 const char *comp_dir, char **new_path)
1874 {
1875 const char *prefix = symbol_conf.source_prefix;
1876
1877 if (sbuild_id && !prefix) {
1878 char prefixed_raw_path[PATH_MAX];
1879
1880 path__join(prefixed_raw_path, sizeof(prefixed_raw_path), comp_dir, raw_path);
1881
1882 if (!get_source_from_debuginfod(prefixed_raw_path, sbuild_id, new_path))
1883 return 0;
1884 }
1885
1886 if (!prefix) {
1887 if (raw_path[0] != '/' && comp_dir)
1888 /* If not an absolute path, try to use comp_dir */
1889 prefix = comp_dir;
1890 else {
1891 if (access(raw_path, R_OK) == 0) {
1892 *new_path = strdup(raw_path);
1893 return *new_path ? 0 : -ENOMEM;
1894 } else
1895 return -errno;
1896 }
1897 }
1898
1899 *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1900 if (!*new_path)
1901 return -ENOMEM;
1902
1903 for (;;) {
1904 sprintf(*new_path, "%s/%s", prefix, raw_path);
1905
1906 if (access(*new_path, R_OK) == 0)
1907 return 0;
1908
1909 if (!symbol_conf.source_prefix) {
1910 /* In case of searching comp_dir, don't retry */
1911 zfree(new_path);
1912 return -errno;
1913 }
1914
1915 switch (errno) {
1916 case ENAMETOOLONG:
1917 case ENOENT:
1918 case EROFS:
1919 case EFAULT:
1920 raw_path = strchr(++raw_path, '/');
1921 if (!raw_path) {
1922 zfree(new_path);
1923 return -ENOENT;
1924 }
1925 continue;
1926
1927 default:
1928 zfree(new_path);
1929 return -errno;
1930 }
1931 }
1932 }
Kernel DRM miscellaneous fixes and cross-tree changes