2 * probe-finder.c : C expression to kprobe event converter
4 * Written by Masami Hiramatsu <mhiramat@redhat.com>
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.
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.
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.
22 #include <sys/utsname.h>
23 #include <sys/types.h>
34 #include <dwarf-regs.h>
40 #include "probe-finder.h"
42 /* Kprobe tracer basic type is up to u64 */
43 #define MAX_BASIC_TYPE_BITS 64
46 * Compare the tail of two strings.
47 * Return 0 if whole of either string is same as another's tail part.
49 static int strtailcmp(const char *s1, const char *s2)
53 while (--i1 >= 0 && --i2 >= 0) {
55 return s1[i1] - s2[i2];
60 /* Line number list operations */
62 /* Add a line to line number list */
63 static int line_list__add_line(struct list_head *head, int line)
68 /* Reverse search, because new line will be the last one */
69 list_for_each_entry_reverse(ln, head, list) {
70 if (ln->line < line) {
73 } else if (ln->line == line) /* Already exist */
76 /* List is empty, or the smallest entry */
79 pr_debug("line list: add a line %u\n", line);
80 ln = zalloc(sizeof(struct line_node));
84 INIT_LIST_HEAD(&ln->list);
85 list_add(&ln->list, p);
89 /* Check if the line in line number list */
90 static int line_list__has_line(struct list_head *head, int line)
94 /* Reverse search, because new line will be the last one */
95 list_for_each_entry(ln, head, list)
102 /* Init line number list */
103 static void line_list__init(struct list_head *head)
105 INIT_LIST_HEAD(head);
108 /* Free line number list */
109 static void line_list__free(struct list_head *head)
111 struct line_node *ln;
112 while (!list_empty(head)) {
113 ln = list_first_entry(head, struct line_node, list);
119 /* Dwarf FL wrappers */
120 static char *debuginfo_path; /* Currently dummy */
122 static const Dwfl_Callbacks offline_callbacks = {
123 .find_debuginfo = dwfl_standard_find_debuginfo,
124 .debuginfo_path = &debuginfo_path,
126 .section_address = dwfl_offline_section_address,
128 /* We use this table for core files too. */
129 .find_elf = dwfl_build_id_find_elf,
132 /* Get a Dwarf from offline image */
133 static Dwarf *dwfl_init_offline_dwarf(int fd, Dwfl **dwflp, Dwarf_Addr *bias)
141 *dwflp = dwfl_begin(&offline_callbacks);
145 mod = dwfl_report_offline(*dwflp, "", "", fd);
149 dbg = dwfl_module_getdwarf(mod, bias);
158 #if _ELFUTILS_PREREQ(0, 148)
159 /* This method is buggy if elfutils is older than 0.148 */
160 static int __linux_kernel_find_elf(Dwfl_Module *mod,
162 const char *module_name,
164 char **file_name, Elf **elfp)
167 const char *path = kernel_get_module_path(module_name);
169 pr_debug2("Use file %s for %s\n", path, module_name);
171 fd = open(path, O_RDONLY);
173 *file_name = strdup(path);
177 /* If failed, try to call standard method */
178 return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
182 static const Dwfl_Callbacks kernel_callbacks = {
183 .find_debuginfo = dwfl_standard_find_debuginfo,
184 .debuginfo_path = &debuginfo_path,
186 .find_elf = __linux_kernel_find_elf,
187 .section_address = dwfl_linux_kernel_module_section_address,
190 /* Get a Dwarf from live kernel image */
191 static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr, Dwfl **dwflp,
199 *dwflp = dwfl_begin(&kernel_callbacks);
203 /* Load the kernel dwarves: Don't care the result here */
204 dwfl_linux_kernel_report_kernel(*dwflp);
205 dwfl_linux_kernel_report_modules(*dwflp);
207 dbg = dwfl_addrdwarf(*dwflp, addr, bias);
208 /* Here, check whether we could get a real dwarf */
210 pr_debug("Failed to find kernel dwarf at %lx\n",
211 (unsigned long)addr);
218 /* With older elfutils, this just support kernel module... */
219 static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr __used, Dwfl **dwflp,
223 const char *path = kernel_get_module_path("kernel");
226 pr_err("Failed to find vmlinux path\n");
230 pr_debug2("Use file %s for debuginfo\n", path);
231 fd = open(path, O_RDONLY);
235 return dwfl_init_offline_dwarf(fd, dwflp, bias);
241 /* Find the realpath of the target file. */
242 static const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
246 const char *src = NULL;
252 ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
256 for (i = 0; i < nfiles; i++) {
257 src = dwarf_filesrc(files, i, NULL, NULL);
258 if (strtailcmp(src, fname) == 0)
266 /* Get DW_AT_comp_dir (should be NULL with older gcc) */
267 static const char *cu_get_comp_dir(Dwarf_Die *cu_die)
269 Dwarf_Attribute attr;
270 if (dwarf_attr(cu_die, DW_AT_comp_dir, &attr) == NULL)
272 return dwarf_formstring(&attr);
275 /* Compare diename and tname */
276 static bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
279 name = dwarf_diename(dw_die);
280 return name ? (strcmp(tname, name) == 0) : false;
284 static Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
286 Dwarf_Attribute attr;
288 if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) &&
289 dwarf_formref_die(&attr, die_mem))
295 /* Get a type die, but skip qualifiers */
296 static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
301 vr_die = die_get_type(vr_die, die_mem);
304 tag = dwarf_tag(vr_die);
305 } while (tag == DW_TAG_const_type ||
306 tag == DW_TAG_restrict_type ||
307 tag == DW_TAG_volatile_type ||
308 tag == DW_TAG_shared_type);
313 /* Get a type die, but skip qualifiers and typedef */
314 static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
317 vr_die = __die_get_real_type(vr_die, die_mem);
318 } while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);
323 static bool die_is_signed_type(Dwarf_Die *tp_die)
325 Dwarf_Attribute attr;
328 if (dwarf_attr(tp_die, DW_AT_encoding, &attr) == NULL ||
329 dwarf_formudata(&attr, &ret) != 0)
332 return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
333 ret == DW_ATE_signed_fixed);
336 static int die_get_byte_size(Dwarf_Die *tp_die)
338 Dwarf_Attribute attr;
341 if (dwarf_attr(tp_die, DW_AT_byte_size, &attr) == NULL ||
342 dwarf_formudata(&attr, &ret) != 0)
348 /* Get data_member_location offset */
349 static int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
351 Dwarf_Attribute attr;
356 if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
359 if (dwarf_formudata(&attr, offs) != 0) {
360 /* DW_AT_data_member_location should be DW_OP_plus_uconst */
361 ret = dwarf_getlocation(&attr, &expr, &nexpr);
362 if (ret < 0 || nexpr == 0)
365 if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
366 pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
367 expr[0].atom, nexpr);
370 *offs = (Dwarf_Word)expr[0].number;
375 /* Return values for die_find callbacks */
377 DIE_FIND_CB_FOUND = 0, /* End of Search */
378 DIE_FIND_CB_CHILD = 1, /* Search only children */
379 DIE_FIND_CB_SIBLING = 2, /* Search only siblings */
380 DIE_FIND_CB_CONTINUE = 3, /* Search children and siblings */
383 /* Search a child die */
384 static Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
385 int (*callback)(Dwarf_Die *, void *),
386 void *data, Dwarf_Die *die_mem)
391 ret = dwarf_child(rt_die, die_mem);
396 ret = callback(die_mem, data);
397 if (ret == DIE_FIND_CB_FOUND)
400 if ((ret & DIE_FIND_CB_CHILD) &&
401 die_find_child(die_mem, callback, data, &child_die)) {
402 memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
405 } while ((ret & DIE_FIND_CB_SIBLING) &&
406 dwarf_siblingof(die_mem, die_mem) == 0);
411 struct __addr_die_search_param {
416 static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
418 struct __addr_die_search_param *ad = data;
420 if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
421 dwarf_haspc(fn_die, ad->addr)) {
422 memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
423 return DWARF_CB_ABORT;
428 /* Search a real subprogram including this line, */
429 static Dwarf_Die *die_find_real_subprogram(Dwarf_Die *cu_die, Dwarf_Addr addr,
432 struct __addr_die_search_param ad;
434 ad.die_mem = die_mem;
435 /* dwarf_getscopes can't find subprogram. */
436 if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
442 /* die_find callback for inline function search */
443 static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
445 Dwarf_Addr *addr = data;
447 if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
448 dwarf_haspc(die_mem, *addr))
449 return DIE_FIND_CB_FOUND;
451 return DIE_FIND_CB_CONTINUE;
454 /* Similar to dwarf_getfuncs, but returns inlined_subroutine if exists. */
455 static Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
458 return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
461 struct __find_variable_param {
466 static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
468 struct __find_variable_param *fvp = data;
471 tag = dwarf_tag(die_mem);
472 if ((tag == DW_TAG_formal_parameter ||
473 tag == DW_TAG_variable) &&
474 die_compare_name(die_mem, fvp->name))
475 return DIE_FIND_CB_FOUND;
477 if (dwarf_haspc(die_mem, fvp->addr))
478 return DIE_FIND_CB_CONTINUE;
480 return DIE_FIND_CB_SIBLING;
483 /* Find a variable called 'name' at given address */
484 static Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
485 Dwarf_Addr addr, Dwarf_Die *die_mem)
487 struct __find_variable_param fvp = { .name = name, .addr = addr};
489 return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
493 static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
495 const char *name = data;
497 if ((dwarf_tag(die_mem) == DW_TAG_member) &&
498 die_compare_name(die_mem, name))
499 return DIE_FIND_CB_FOUND;
501 return DIE_FIND_CB_SIBLING;
504 /* Find a member called 'name' */
505 static Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
508 return die_find_child(st_die, __die_find_member_cb, (void *)name,
512 /* Get the name of given variable DIE */
513 static int die_get_typename(Dwarf_Die *vr_die, char *buf, int len)
517 const char *tmp = "";
519 if (__die_get_real_type(vr_die, &type) == NULL)
522 tag = dwarf_tag(&type);
523 if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
525 else if (tag == DW_TAG_subroutine_type) {
526 /* Function pointer */
527 ret = snprintf(buf, len, "(function_type)");
528 return (ret >= len) ? -E2BIG : ret;
530 if (!dwarf_diename(&type))
532 if (tag == DW_TAG_union_type)
534 else if (tag == DW_TAG_structure_type)
536 /* Write a base name */
537 ret = snprintf(buf, len, "%s%s", tmp, dwarf_diename(&type));
538 return (ret >= len) ? -E2BIG : ret;
540 ret = die_get_typename(&type, buf, len);
542 ret2 = snprintf(buf + ret, len - ret, "%s", tmp);
543 ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
548 /* Get the name and type of given variable DIE, stored as "type\tname" */
549 static int die_get_varname(Dwarf_Die *vr_die, char *buf, int len)
553 ret = die_get_typename(vr_die, buf, len);
555 pr_debug("Failed to get type, make it unknown.\n");
556 ret = snprintf(buf, len, "(unknown_type)");
559 ret2 = snprintf(buf + ret, len - ret, "\t%s",
560 dwarf_diename(vr_die));
561 ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
567 * Probe finder related functions
570 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
572 struct probe_trace_arg_ref *ref;
573 ref = zalloc(sizeof(struct probe_trace_arg_ref));
580 * Convert a location into trace_arg.
581 * If tvar == NULL, this just checks variable can be converted.
583 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
585 struct probe_trace_arg *tvar)
587 Dwarf_Attribute attr;
596 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
599 /* TODO: handle more than 1 exprs */
600 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL ||
601 dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0 ||
603 /* TODO: Support const_value */
607 if (op->atom == DW_OP_addr) {
611 /* Static variables on memory (not stack), make @varname */
612 ret = strlen(dwarf_diename(vr_die));
613 tvar->value = zalloc(ret + 2);
614 if (tvar->value == NULL)
616 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
617 tvar->ref = alloc_trace_arg_ref((long)offs);
618 if (tvar->ref == NULL)
623 /* If this is based on frame buffer, set the offset */
624 if (op->atom == DW_OP_fbreg) {
632 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
633 regn = op->atom - DW_OP_breg0;
636 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
637 regn = op->atom - DW_OP_reg0;
638 } else if (op->atom == DW_OP_bregx) {
642 } else if (op->atom == DW_OP_regx) {
645 pr_debug("DW_OP %x is not supported.\n", op->atom);
652 regs = get_arch_regstr(regn);
654 /* This should be a bug in DWARF or this tool */
655 pr_warning("Mapping for DWARF register number %u "
656 "missing on this architecture.", regn);
660 tvar->value = strdup(regs);
661 if (tvar->value == NULL)
665 tvar->ref = alloc_trace_arg_ref((long)offs);
666 if (tvar->ref == NULL)
672 static int convert_variable_type(Dwarf_Die *vr_die,
673 struct probe_trace_arg *tvar,
676 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
681 /* TODO: check all types */
682 if (cast && strcmp(cast, "string") != 0) {
683 /* Non string type is OK */
684 tvar->type = strdup(cast);
685 return (tvar->type == NULL) ? -ENOMEM : 0;
688 if (die_get_real_type(vr_die, &type) == NULL) {
689 pr_warning("Failed to get a type information of %s.\n",
690 dwarf_diename(vr_die));
694 pr_debug("%s type is %s.\n",
695 dwarf_diename(vr_die), dwarf_diename(&type));
697 if (cast && strcmp(cast, "string") == 0) { /* String type */
698 ret = dwarf_tag(&type);
699 if (ret != DW_TAG_pointer_type &&
700 ret != DW_TAG_array_type) {
701 pr_warning("Failed to cast into string: "
702 "%s(%s) is not a pointer nor array.",
703 dwarf_diename(vr_die), dwarf_diename(&type));
706 if (ret == DW_TAG_pointer_type) {
707 if (die_get_real_type(&type, &type) == NULL) {
708 pr_warning("Failed to get a type information.");
712 ref_ptr = &(*ref_ptr)->next;
713 /* Add new reference with offset +0 */
714 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
715 if (*ref_ptr == NULL) {
716 pr_warning("Out of memory error\n");
720 if (!die_compare_name(&type, "char") &&
721 !die_compare_name(&type, "unsigned char")) {
722 pr_warning("Failed to cast into string: "
723 "%s is not (unsigned) char *.",
724 dwarf_diename(vr_die));
727 tvar->type = strdup(cast);
728 return (tvar->type == NULL) ? -ENOMEM : 0;
731 ret = die_get_byte_size(&type) * 8;
733 /* Check the bitwidth */
734 if (ret > MAX_BASIC_TYPE_BITS) {
735 pr_info("%s exceeds max-bitwidth."
736 " Cut down to %d bits.\n",
737 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
738 ret = MAX_BASIC_TYPE_BITS;
741 ret = snprintf(buf, 16, "%c%d",
742 die_is_signed_type(&type) ? 's' : 'u', ret);
743 if (ret < 0 || ret >= 16) {
746 pr_warning("Failed to convert variable type: %s\n",
750 tvar->type = strdup(buf);
751 if (tvar->type == NULL)
757 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
758 struct perf_probe_arg_field *field,
759 struct probe_trace_arg_ref **ref_ptr,
762 struct probe_trace_arg_ref *ref = *ref_ptr;
767 pr_debug("converting %s in %s\n", field->name, varname);
768 if (die_get_real_type(vr_die, &type) == NULL) {
769 pr_warning("Failed to get the type of %s.\n", varname);
772 pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
773 tag = dwarf_tag(&type);
775 if (field->name[0] == '[' &&
776 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
778 /* Save original type for next field */
779 memcpy(die_mem, &type, sizeof(*die_mem));
780 /* Get the type of this array */
781 if (die_get_real_type(&type, &type) == NULL) {
782 pr_warning("Failed to get the type of %s.\n", varname);
785 pr_debug2("Array real type: (%x)\n",
786 (unsigned)dwarf_dieoffset(&type));
787 if (tag == DW_TAG_pointer_type) {
788 ref = zalloc(sizeof(struct probe_trace_arg_ref));
792 (*ref_ptr)->next = ref;
796 ref->offset += die_get_byte_size(&type) * field->index;
798 /* Save vr_die for converting types */
799 memcpy(die_mem, vr_die, sizeof(*die_mem));
801 } else if (tag == DW_TAG_pointer_type) {
802 /* Check the pointer and dereference */
804 pr_err("Semantic error: %s must be referred by '->'\n",
808 /* Get the type pointed by this pointer */
809 if (die_get_real_type(&type, &type) == NULL) {
810 pr_warning("Failed to get the type of %s.\n", varname);
813 /* Verify it is a data structure */
814 if (dwarf_tag(&type) != DW_TAG_structure_type) {
815 pr_warning("%s is not a data structure.\n", varname);
819 ref = zalloc(sizeof(struct probe_trace_arg_ref));
823 (*ref_ptr)->next = ref;
827 /* Verify it is a data structure */
828 if (tag != DW_TAG_structure_type) {
829 pr_warning("%s is not a data structure.\n", varname);
832 if (field->name[0] == '[') {
833 pr_err("Semantic error: %s is not a pointor nor array.",
838 pr_err("Semantic error: %s must be referred by '.'\n",
843 pr_warning("Structure on a register is not "
849 if (die_find_member(&type, field->name, die_mem) == NULL) {
850 pr_warning("%s(tyep:%s) has no member %s.\n", varname,
851 dwarf_diename(&type), field->name);
855 /* Get the offset of the field */
856 ret = die_get_data_member_location(die_mem, &offs);
858 pr_warning("Failed to get the offset of %s.\n", field->name);
861 ref->offset += (long)offs;
864 /* Converting next field */
866 return convert_variable_fields(die_mem, field->name,
867 field->next, &ref, die_mem);
872 /* Show a variables in kprobe event format */
873 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
878 pr_debug("Converting variable %s into trace event.\n",
879 dwarf_diename(vr_die));
881 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
884 pr_err("Failed to find the location of %s at this address.\n"
885 " Perhaps, it has been optimized out.\n", pf->pvar->var);
886 else if (ret == -ENOTSUP)
887 pr_err("Sorry, we don't support this variable location yet.\n");
888 else if (pf->pvar->field) {
889 ret = convert_variable_fields(vr_die, pf->pvar->var,
890 pf->pvar->field, &pf->tvar->ref,
895 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
896 /* *expr will be cached in libdw. Don't free it. */
900 /* Find a variable in a subprogram die */
901 static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
903 Dwarf_Die vr_die, *scopes;
907 if (!is_c_varname(pf->pvar->var)) {
908 /* Copy raw parameters */
909 pf->tvar->value = strdup(pf->pvar->var);
910 if (pf->tvar->value == NULL)
912 if (pf->pvar->type) {
913 pf->tvar->type = strdup(pf->pvar->type);
914 if (pf->tvar->type == NULL)
917 if (pf->pvar->name) {
918 pf->tvar->name = strdup(pf->pvar->name);
919 if (pf->tvar->name == NULL)
922 pf->tvar->name = NULL;
927 pf->tvar->name = strdup(pf->pvar->name);
929 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
932 ptr = strchr(buf, ':'); /* Change type separator to _ */
935 pf->tvar->name = strdup(buf);
937 if (pf->tvar->name == NULL)
940 pr_debug("Searching '%s' variable in context.\n",
942 /* Search child die for local variables and parameters. */
943 if (die_find_variable_at(sp_die, pf->pvar->var, pf->addr, &vr_die))
944 ret = convert_variable(&vr_die, pf);
946 /* Search upper class */
947 nscopes = dwarf_getscopes_die(sp_die, &scopes);
948 while (nscopes-- > 1) {
949 pr_debug("Searching variables in %s\n",
950 dwarf_diename(&scopes[nscopes]));
951 /* We should check this scope, so give dummy address */
952 if (die_find_variable_at(&scopes[nscopes],
955 ret = convert_variable(&vr_die, pf);
965 pr_warning("Failed to find '%s' in this function.\n",
970 /* Convert subprogram DIE to trace point */
971 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr,
972 bool retprobe, struct probe_trace_point *tp)
977 /* Copy the name of probe point */
978 name = dwarf_diename(sp_die);
980 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
981 pr_warning("Failed to get entry pc of %s\n",
982 dwarf_diename(sp_die));
985 tp->symbol = strdup(name);
986 if (tp->symbol == NULL)
988 tp->offset = (unsigned long)(paddr - eaddr);
990 /* This function has no name. */
991 tp->offset = (unsigned long)paddr;
993 /* Return probe must be on the head of a subprogram */
995 if (eaddr != paddr) {
996 pr_warning("Return probe must be on the head of"
997 " a real function\n");
1000 tp->retprobe = true;
1006 /* Call probe_finder callback with real subprogram DIE */
1007 static int call_probe_finder(Dwarf_Die *sp_die, struct probe_finder *pf)
1010 Dwarf_Attribute fb_attr;
1014 /* If no real subprogram, find a real one */
1015 if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
1016 sp_die = die_find_real_subprogram(&pf->cu_die,
1017 pf->addr, &die_mem);
1019 pr_warning("Failed to find probe point in any "
1025 /* Get the frame base attribute/ops */
1026 dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
1027 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
1028 if (ret <= 0 || nops == 0) {
1030 #if _ELFUTILS_PREREQ(0, 142)
1031 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
1034 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
1035 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
1036 pr_warning("Failed to get CFA on 0x%jx\n",
1037 (uintmax_t)pf->addr);
1043 /* Call finder's callback handler */
1044 ret = pf->callback(sp_die, pf);
1046 /* *pf->fb_ops will be cached in libdw. Don't free it. */
1052 /* Find probe point from its line number */
1053 static int find_probe_point_by_line(struct probe_finder *pf)
1062 if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
1063 pr_warning("No source lines found in this CU.\n");
1067 for (i = 0; i < nlines && ret == 0; i++) {
1068 line = dwarf_onesrcline(lines, i);
1069 if (dwarf_lineno(line, &lineno) != 0 ||
1073 /* TODO: Get fileno from line, but how? */
1074 if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
1077 if (dwarf_lineaddr(line, &addr) != 0) {
1078 pr_warning("Failed to get the address of the line.\n");
1081 pr_debug("Probe line found: line[%d]:%d addr:0x%jx\n",
1082 (int)i, lineno, (uintmax_t)addr);
1085 ret = call_probe_finder(NULL, pf);
1086 /* Continuing, because target line might be inlined. */
1091 /* Find lines which match lazy pattern */
1092 static int find_lazy_match_lines(struct list_head *head,
1093 const char *fname, const char *pat)
1095 char *fbuf, *p1, *p2;
1096 int fd, line, nlines = -1;
1099 fd = open(fname, O_RDONLY);
1101 pr_warning("Failed to open %s: %s\n", fname, strerror(-fd));
1105 if (fstat(fd, &st) < 0) {
1106 pr_warning("Failed to get the size of %s: %s\n",
1107 fname, strerror(errno));
1113 fbuf = malloc(st.st_size + 2);
1116 if (read(fd, fbuf, st.st_size) < 0) {
1117 pr_warning("Failed to read %s: %s\n", fname, strerror(errno));
1121 fbuf[st.st_size] = '\n'; /* Dummy line */
1122 fbuf[st.st_size + 1] = '\0';
1126 while ((p2 = strchr(p1, '\n')) != NULL) {
1128 if (strlazymatch(p1, pat)) {
1129 line_list__add_line(head, line);
1142 /* Find probe points from lazy pattern */
1143 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
1153 if (list_empty(&pf->lcache)) {
1154 /* Matching lazy line pattern */
1155 ret = find_lazy_match_lines(&pf->lcache, pf->fname,
1156 pf->pev->point.lazy_line);
1158 pr_debug("No matched lines found in %s.\n", pf->fname);
1164 if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
1165 pr_warning("No source lines found in this CU.\n");
1169 for (i = 0; i < nlines && ret >= 0; i++) {
1170 line = dwarf_onesrcline(lines, i);
1172 if (dwarf_lineno(line, &lineno) != 0 ||
1173 !line_list__has_line(&pf->lcache, lineno))
1176 /* TODO: Get fileno from line, but how? */
1177 if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
1180 if (dwarf_lineaddr(line, &addr) != 0) {
1181 pr_debug("Failed to get the address of line %d.\n",
1186 /* Address filtering 1: does sp_die include addr? */
1187 if (!dwarf_haspc(sp_die, addr))
1189 /* Address filtering 2: No child include addr? */
1190 if (die_find_inlinefunc(sp_die, addr, &die_mem))
1194 pr_debug("Probe line found: line[%d]:%d addr:0x%llx\n",
1195 (int)i, lineno, (unsigned long long)addr);
1198 ret = call_probe_finder(sp_die, pf);
1199 /* Continuing, because target line might be inlined. */
1201 /* TODO: deallocate lines, but how? */
1205 /* Callback parameter with return value */
1206 struct dwarf_callback_param {
1211 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
1213 struct dwarf_callback_param *param = data;
1214 struct probe_finder *pf = param->data;
1215 struct perf_probe_point *pp = &pf->pev->point;
1219 param->retval = find_probe_point_lazy(in_die, pf);
1221 /* Get probe address */
1222 if (dwarf_entrypc(in_die, &addr) != 0) {
1223 pr_warning("Failed to get entry pc of %s.\n",
1224 dwarf_diename(in_die));
1225 param->retval = -ENOENT;
1226 return DWARF_CB_ABORT;
1229 pf->addr += pp->offset;
1230 pr_debug("found inline addr: 0x%jx\n",
1231 (uintmax_t)pf->addr);
1233 param->retval = call_probe_finder(in_die, pf);
1234 if (param->retval < 0)
1235 return DWARF_CB_ABORT;
1241 /* Search function from function name */
1242 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
1244 struct dwarf_callback_param *param = data;
1245 struct probe_finder *pf = param->data;
1246 struct perf_probe_point *pp = &pf->pev->point;
1248 /* Check tag and diename */
1249 if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
1250 !die_compare_name(sp_die, pp->function))
1253 pf->fname = dwarf_decl_file(sp_die);
1254 if (pp->line) { /* Function relative line */
1255 dwarf_decl_line(sp_die, &pf->lno);
1256 pf->lno += pp->line;
1257 param->retval = find_probe_point_by_line(pf);
1258 } else if (!dwarf_func_inline(sp_die)) {
1261 param->retval = find_probe_point_lazy(sp_die, pf);
1263 if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
1264 pr_warning("Failed to get entry pc of %s.\n",
1265 dwarf_diename(sp_die));
1266 param->retval = -ENOENT;
1267 return DWARF_CB_ABORT;
1269 pf->addr += pp->offset;
1270 /* TODO: Check the address in this function */
1271 param->retval = call_probe_finder(sp_die, pf);
1274 struct dwarf_callback_param _param = {.data = (void *)pf,
1276 /* Inlined function: search instances */
1277 dwarf_func_inline_instances(sp_die, probe_point_inline_cb,
1279 param->retval = _param.retval;
1282 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1285 static int find_probe_point_by_func(struct probe_finder *pf)
1287 struct dwarf_callback_param _param = {.data = (void *)pf,
1289 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1290 return _param.retval;
1293 /* Find probe points from debuginfo */
1294 static int find_probes(int fd, struct probe_finder *pf)
1296 struct perf_probe_point *pp = &pf->pev->point;
1297 Dwarf_Off off, noff;
1302 Dwarf_Addr bias; /* Currently ignored */
1305 dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
1307 pr_warning("No dwarf info found in the vmlinux - "
1308 "please rebuild with CONFIG_DEBUG_INFO=y.\n");
1312 #if _ELFUTILS_PREREQ(0, 142)
1313 /* Get the call frame information from this dwarf */
1314 pf->cfi = dwarf_getcfi(dbg);
1318 line_list__init(&pf->lcache);
1319 /* Loop on CUs (Compilation Unit) */
1320 while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) &&
1322 /* Get the DIE(Debugging Information Entry) of this CU */
1323 diep = dwarf_offdie(dbg, off + cuhl, &pf->cu_die);
1327 /* Check if target file is included. */
1329 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1333 if (!pp->file || pf->fname) {
1335 ret = find_probe_point_by_func(pf);
1336 else if (pp->lazy_line)
1337 ret = find_probe_point_lazy(NULL, pf);
1340 ret = find_probe_point_by_line(pf);
1345 line_list__free(&pf->lcache);
1352 /* Add a found probe point into trace event list */
1353 static int add_probe_trace_event(Dwarf_Die *sp_die, struct probe_finder *pf)
1355 struct trace_event_finder *tf =
1356 container_of(pf, struct trace_event_finder, pf);
1357 struct probe_trace_event *tev;
1360 /* Check number of tevs */
1361 if (tf->ntevs == tf->max_tevs) {
1362 pr_warning("Too many( > %d) probe point found.\n",
1366 tev = &tf->tevs[tf->ntevs++];
1368 ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
1373 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1376 /* Find each argument */
1377 tev->nargs = pf->pev->nargs;
1378 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1379 if (tev->args == NULL)
1381 for (i = 0; i < pf->pev->nargs; i++) {
1382 pf->pvar = &pf->pev->args[i];
1383 pf->tvar = &tev->args[i];
1384 ret = find_variable(sp_die, pf);
1392 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1393 int find_probe_trace_events(int fd, struct perf_probe_event *pev,
1394 struct probe_trace_event **tevs, int max_tevs)
1396 struct trace_event_finder tf = {
1397 .pf = {.pev = pev, .callback = add_probe_trace_event},
1398 .max_tevs = max_tevs};
1401 /* Allocate result tevs array */
1402 *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
1409 ret = find_probes(fd, &tf.pf);
1416 return (ret < 0) ? ret : tf.ntevs;
1419 #define MAX_VAR_LEN 64
1421 /* Collect available variables in this scope */
1422 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1424 struct available_var_finder *af = data;
1425 struct variable_list *vl;
1426 char buf[MAX_VAR_LEN];
1429 vl = &af->vls[af->nvls - 1];
1431 tag = dwarf_tag(die_mem);
1432 if (tag == DW_TAG_formal_parameter ||
1433 tag == DW_TAG_variable) {
1434 ret = convert_variable_location(die_mem, af->pf.addr,
1435 af->pf.fb_ops, NULL);
1437 ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1438 pr_debug2("Add new var: %s\n", buf);
1440 strlist__add(vl->vars, buf);
1444 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1445 return DIE_FIND_CB_CONTINUE;
1447 return DIE_FIND_CB_SIBLING;
1450 /* Add a found vars into available variables list */
1451 static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf)
1453 struct available_var_finder *af =
1454 container_of(pf, struct available_var_finder, pf);
1455 struct variable_list *vl;
1456 Dwarf_Die die_mem, *scopes = NULL;
1459 /* Check number of tevs */
1460 if (af->nvls == af->max_vls) {
1461 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1464 vl = &af->vls[af->nvls++];
1466 ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
1471 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1474 /* Find local variables */
1475 vl->vars = strlist__new(true, NULL);
1476 if (vl->vars == NULL)
1479 die_find_child(sp_die, collect_variables_cb, (void *)af, &die_mem);
1481 /* Find external variables */
1484 /* Don't need to search child DIE for externs. */
1486 nscopes = dwarf_getscopes_die(sp_die, &scopes);
1487 while (nscopes-- > 1)
1488 die_find_child(&scopes[nscopes], collect_variables_cb,
1489 (void *)af, &die_mem);
1494 if (strlist__empty(vl->vars)) {
1495 strlist__delete(vl->vars);
1502 /* Find available variables at given probe point */
1503 int find_available_vars_at(int fd, struct perf_probe_event *pev,
1504 struct variable_list **vls, int max_vls,
1507 struct available_var_finder af = {
1508 .pf = {.pev = pev, .callback = add_available_vars},
1509 .max_vls = max_vls, .externs = externs};
1512 /* Allocate result vls array */
1513 *vls = zalloc(sizeof(struct variable_list) * max_vls);
1520 ret = find_probes(fd, &af.pf);
1522 /* Free vlist for error */
1524 if (af.vls[af.nvls].point.symbol)
1525 free(af.vls[af.nvls].point.symbol);
1526 if (af.vls[af.nvls].vars)
1527 strlist__delete(af.vls[af.nvls].vars);
1534 return (ret < 0) ? ret : af.nvls;
1537 /* Reverse search */
1538 int find_perf_probe_point(unsigned long addr, struct perf_probe_point *ppt)
1540 Dwarf_Die cudie, spdie, indie;
1544 Dwarf_Addr laddr, eaddr, bias = 0;
1546 int lineno, ret = 0;
1549 /* Open the live linux kernel */
1550 dbg = dwfl_init_live_kernel_dwarf(addr, &dwfl, &bias);
1552 pr_warning("No dwarf info found in the vmlinux - "
1553 "please rebuild with CONFIG_DEBUG_INFO=y.\n");
1558 /* Adjust address with bias */
1561 if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr - bias, &cudie)) {
1562 pr_warning("No CU DIE is found at %lx\n", addr);
1567 /* Find a corresponding line */
1568 line = dwarf_getsrc_die(&cudie, (Dwarf_Addr)addr);
1570 if (dwarf_lineaddr(line, &laddr) == 0 &&
1571 (Dwarf_Addr)addr == laddr &&
1572 dwarf_lineno(line, &lineno) == 0) {
1573 tmp = dwarf_linesrc(line, NULL, NULL);
1576 ppt->file = strdup(tmp);
1577 if (ppt->file == NULL) {
1586 /* Find a corresponding function */
1587 if (die_find_real_subprogram(&cudie, (Dwarf_Addr)addr, &spdie)) {
1588 tmp = dwarf_diename(&spdie);
1589 if (!tmp || dwarf_entrypc(&spdie, &eaddr) != 0)
1593 if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr,
1595 /* addr in an inline function */
1596 tmp = dwarf_diename(&indie);
1599 ret = dwarf_decl_line(&indie, &lineno);
1601 if (eaddr == addr) { /* Function entry */
1605 ret = dwarf_decl_line(&spdie, &lineno);
1608 /* Make a relative line number */
1609 ppt->line -= lineno;
1613 /* We don't have a line number, let's use offset */
1614 ppt->offset = addr - (unsigned long)eaddr;
1616 ppt->function = strdup(tmp);
1617 if (ppt->function == NULL) {
1628 ret = found ? 1 : 0;
1632 /* Add a line and store the src path */
1633 static int line_range_add_line(const char *src, unsigned int lineno,
1634 struct line_range *lr)
1636 /* Copy source path */
1638 lr->path = strdup(src);
1639 if (lr->path == NULL)
1642 return line_list__add_line(&lr->line_list, lineno);
1645 /* Search function declaration lines */
1646 static int line_range_funcdecl_cb(Dwarf_Die *sp_die, void *data)
1648 struct dwarf_callback_param *param = data;
1649 struct line_finder *lf = param->data;
1653 src = dwarf_decl_file(sp_die);
1654 if (src && strtailcmp(src, lf->fname) != 0)
1657 if (dwarf_decl_line(sp_die, &lineno) != 0 ||
1658 (lf->lno_s > lineno || lf->lno_e < lineno))
1661 param->retval = line_range_add_line(src, lineno, lf->lr);
1662 if (param->retval < 0)
1663 return DWARF_CB_ABORT;
1667 static int find_line_range_func_decl_lines(struct line_finder *lf)
1669 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1670 dwarf_getfuncs(&lf->cu_die, line_range_funcdecl_cb, ¶m, 0);
1671 return param.retval;
1674 /* Find line range from its line number */
1675 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1681 int lineno, ret = 0;
1685 line_list__init(&lf->lr->line_list);
1686 if (dwarf_getsrclines(&lf->cu_die, &lines, &nlines) != 0) {
1687 pr_warning("No source lines found in this CU.\n");
1691 /* Search probable lines on lines list */
1692 for (i = 0; i < nlines; i++) {
1693 line = dwarf_onesrcline(lines, i);
1694 if (dwarf_lineno(line, &lineno) != 0 ||
1695 (lf->lno_s > lineno || lf->lno_e < lineno))
1699 /* Address filtering 1: does sp_die include addr? */
1700 if (dwarf_lineaddr(line, &addr) != 0 ||
1701 !dwarf_haspc(sp_die, addr))
1704 /* Address filtering 2: No child include addr? */
1705 if (die_find_inlinefunc(sp_die, addr, &die_mem))
1709 /* TODO: Get fileno from line, but how? */
1710 src = dwarf_linesrc(line, NULL, NULL);
1711 if (strtailcmp(src, lf->fname) != 0)
1714 ret = line_range_add_line(src, lineno, lf->lr);
1720 * Dwarf lines doesn't include function declarations. We have to
1721 * check functions list or given function.
1724 src = dwarf_decl_file(sp_die);
1725 if (src && dwarf_decl_line(sp_die, &lineno) == 0 &&
1726 (lf->lno_s <= lineno && lf->lno_e >= lineno))
1727 ret = line_range_add_line(src, lineno, lf->lr);
1729 ret = find_line_range_func_decl_lines(lf);
1733 if (!list_empty(&lf->lr->line_list))
1734 ret = lf->found = 1;
1736 ret = 0; /* Lines are not found */
1739 lf->lr->path = NULL;
1744 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1746 struct dwarf_callback_param *param = data;
1748 param->retval = find_line_range_by_line(in_die, param->data);
1749 return DWARF_CB_ABORT; /* No need to find other instances */
1752 /* Search function from function name */
1753 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1755 struct dwarf_callback_param *param = data;
1756 struct line_finder *lf = param->data;
1757 struct line_range *lr = lf->lr;
1759 pr_debug("find (%llx) %s\n",
1760 (unsigned long long)dwarf_dieoffset(sp_die),
1761 dwarf_diename(sp_die));
1762 if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
1763 die_compare_name(sp_die, lr->function)) {
1764 lf->fname = dwarf_decl_file(sp_die);
1765 dwarf_decl_line(sp_die, &lr->offset);
1766 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1767 lf->lno_s = lr->offset + lr->start;
1768 if (lf->lno_s < 0) /* Overflow */
1769 lf->lno_s = INT_MAX;
1770 lf->lno_e = lr->offset + lr->end;
1771 if (lf->lno_e < 0) /* Overflow */
1772 lf->lno_e = INT_MAX;
1773 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1774 lr->start = lf->lno_s;
1775 lr->end = lf->lno_e;
1776 if (dwarf_func_inline(sp_die)) {
1777 struct dwarf_callback_param _param;
1778 _param.data = (void *)lf;
1780 dwarf_func_inline_instances(sp_die,
1781 line_range_inline_cb,
1783 param->retval = _param.retval;
1785 param->retval = find_line_range_by_line(sp_die, lf);
1786 return DWARF_CB_ABORT;
1791 static int find_line_range_by_func(struct line_finder *lf)
1793 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1794 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, ¶m, 0);
1795 return param.retval;
1798 int find_line_range(int fd, struct line_range *lr)
1800 struct line_finder lf = {.lr = lr, .found = 0};
1802 Dwarf_Off off = 0, noff;
1807 Dwarf_Addr bias; /* Currently ignored */
1808 const char *comp_dir;
1810 dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
1812 pr_warning("No dwarf info found in the vmlinux - "
1813 "please rebuild with CONFIG_DEBUG_INFO=y.\n");
1817 /* Loop on CUs (Compilation Unit) */
1818 while (!lf.found && ret >= 0) {
1819 if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
1822 /* Get the DIE(Debugging Information Entry) of this CU */
1823 diep = dwarf_offdie(dbg, off + cuhl, &lf.cu_die);
1827 /* Check if target file is included. */
1829 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1833 if (!lr->file || lf.fname) {
1835 ret = find_line_range_by_func(&lf);
1837 lf.lno_s = lr->start;
1839 ret = find_line_range_by_line(NULL, &lf);
1845 /* Store comp_dir */
1847 comp_dir = cu_get_comp_dir(&lf.cu_die);
1849 lr->comp_dir = strdup(comp_dir);
1855 pr_debug("path: %s\n", lr->path);
1857 return (ret < 0) ? ret : lf.found;