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 /* Walker on lines (Note: line number will not be sorted) */
462 typedef int (* line_walk_handler_t) (const char *fname, int lineno,
463 Dwarf_Addr addr, void *data);
465 struct __line_walk_param {
466 line_walk_handler_t handler;
471 /* Walk on decl lines in given DIE */
472 static int __die_walk_funclines(Dwarf_Die *sp_die,
473 line_walk_handler_t handler, void *data)
479 /* Handle function declaration line */
480 fname = dwarf_decl_file(sp_die);
481 if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
482 dwarf_entrypc(sp_die, &addr) == 0) {
483 ret = handler(fname, lineno, addr, data);
489 static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
491 struct __line_walk_param *lw = data;
493 lw->retval = __die_walk_funclines(sp_die, lw->handler, lw->data);
495 return DWARF_CB_ABORT;
501 * Walk on lines inside given PDIE. If the PDIE is subprogram, walk only on
502 * the lines inside the subprogram, otherwise PDIE must be a CU DIE.
504 static int die_walk_lines(Dwarf_Die *pdie, line_walk_handler_t handler,
512 Dwarf_Die die_mem, *cu_die;
516 if (dwarf_tag(pdie) == DW_TAG_subprogram)
517 cu_die = dwarf_diecu(pdie, &die_mem, NULL, NULL);
521 pr_debug2("Failed to get CU from subprogram\n");
525 /* Get lines list in the CU */
526 if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
527 pr_debug2("Failed to get source lines on this CU.\n");
530 pr_debug2("Get %zd lines from this CU\n", nlines);
532 /* Walk on the lines on lines list */
533 for (i = 0; i < nlines; i++) {
534 line = dwarf_onesrcline(lines, i);
536 dwarf_lineno(line, &lineno) != 0 ||
537 dwarf_lineaddr(line, &addr) != 0) {
538 pr_debug2("Failed to get line info. "
539 "Possible error in debuginfo.\n");
542 /* Filter lines based on address */
546 * The line is included in given function, and
547 * no inline block includes it.
549 if (!dwarf_haspc(pdie, addr) ||
550 die_find_inlinefunc(pdie, addr, &die_mem))
552 /* Get source line */
553 fname = dwarf_linesrc(line, NULL, NULL);
555 ret = handler(fname, lineno, addr, data);
561 * Dwarf lines doesn't include function declarations and inlined
562 * subroutines. We have to check functions list or given function.
565 ret = __die_walk_funclines(pdie, handler, data);
567 struct __line_walk_param param = {
572 dwarf_getfuncs(cu_die, __die_walk_culines_cb, ¶m, 0);
579 struct __find_variable_param {
584 static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
586 struct __find_variable_param *fvp = data;
589 tag = dwarf_tag(die_mem);
590 if ((tag == DW_TAG_formal_parameter ||
591 tag == DW_TAG_variable) &&
592 die_compare_name(die_mem, fvp->name))
593 return DIE_FIND_CB_FOUND;
595 if (dwarf_haspc(die_mem, fvp->addr))
596 return DIE_FIND_CB_CONTINUE;
598 return DIE_FIND_CB_SIBLING;
601 /* Find a variable called 'name' at given address */
602 static Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
603 Dwarf_Addr addr, Dwarf_Die *die_mem)
605 struct __find_variable_param fvp = { .name = name, .addr = addr};
607 return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
611 static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
613 const char *name = data;
615 if ((dwarf_tag(die_mem) == DW_TAG_member) &&
616 die_compare_name(die_mem, name))
617 return DIE_FIND_CB_FOUND;
619 return DIE_FIND_CB_SIBLING;
622 /* Find a member called 'name' */
623 static Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
626 return die_find_child(st_die, __die_find_member_cb, (void *)name,
630 /* Get the name of given variable DIE */
631 static int die_get_typename(Dwarf_Die *vr_die, char *buf, int len)
635 const char *tmp = "";
637 if (__die_get_real_type(vr_die, &type) == NULL)
640 tag = dwarf_tag(&type);
641 if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
643 else if (tag == DW_TAG_subroutine_type) {
644 /* Function pointer */
645 ret = snprintf(buf, len, "(function_type)");
646 return (ret >= len) ? -E2BIG : ret;
648 if (!dwarf_diename(&type))
650 if (tag == DW_TAG_union_type)
652 else if (tag == DW_TAG_structure_type)
654 /* Write a base name */
655 ret = snprintf(buf, len, "%s%s", tmp, dwarf_diename(&type));
656 return (ret >= len) ? -E2BIG : ret;
658 ret = die_get_typename(&type, buf, len);
660 ret2 = snprintf(buf + ret, len - ret, "%s", tmp);
661 ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
666 /* Get the name and type of given variable DIE, stored as "type\tname" */
667 static int die_get_varname(Dwarf_Die *vr_die, char *buf, int len)
671 ret = die_get_typename(vr_die, buf, len);
673 pr_debug("Failed to get type, make it unknown.\n");
674 ret = snprintf(buf, len, "(unknown_type)");
677 ret2 = snprintf(buf + ret, len - ret, "\t%s",
678 dwarf_diename(vr_die));
679 ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
685 * Probe finder related functions
688 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
690 struct probe_trace_arg_ref *ref;
691 ref = zalloc(sizeof(struct probe_trace_arg_ref));
698 * Convert a location into trace_arg.
699 * If tvar == NULL, this just checks variable can be converted.
701 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
703 struct probe_trace_arg *tvar)
705 Dwarf_Attribute attr;
714 if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
717 /* TODO: handle more than 1 exprs */
718 if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL ||
719 dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0 ||
721 /* TODO: Support const_value */
725 if (op->atom == DW_OP_addr) {
729 /* Static variables on memory (not stack), make @varname */
730 ret = strlen(dwarf_diename(vr_die));
731 tvar->value = zalloc(ret + 2);
732 if (tvar->value == NULL)
734 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
735 tvar->ref = alloc_trace_arg_ref((long)offs);
736 if (tvar->ref == NULL)
741 /* If this is based on frame buffer, set the offset */
742 if (op->atom == DW_OP_fbreg) {
750 if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
751 regn = op->atom - DW_OP_breg0;
754 } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
755 regn = op->atom - DW_OP_reg0;
756 } else if (op->atom == DW_OP_bregx) {
760 } else if (op->atom == DW_OP_regx) {
763 pr_debug("DW_OP %x is not supported.\n", op->atom);
770 regs = get_arch_regstr(regn);
772 /* This should be a bug in DWARF or this tool */
773 pr_warning("Mapping for the register number %u "
774 "missing on this architecture.\n", regn);
778 tvar->value = strdup(regs);
779 if (tvar->value == NULL)
783 tvar->ref = alloc_trace_arg_ref((long)offs);
784 if (tvar->ref == NULL)
790 static int convert_variable_type(Dwarf_Die *vr_die,
791 struct probe_trace_arg *tvar,
794 struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
799 /* TODO: check all types */
800 if (cast && strcmp(cast, "string") != 0) {
801 /* Non string type is OK */
802 tvar->type = strdup(cast);
803 return (tvar->type == NULL) ? -ENOMEM : 0;
806 if (die_get_real_type(vr_die, &type) == NULL) {
807 pr_warning("Failed to get a type information of %s.\n",
808 dwarf_diename(vr_die));
812 pr_debug("%s type is %s.\n",
813 dwarf_diename(vr_die), dwarf_diename(&type));
815 if (cast && strcmp(cast, "string") == 0) { /* String type */
816 ret = dwarf_tag(&type);
817 if (ret != DW_TAG_pointer_type &&
818 ret != DW_TAG_array_type) {
819 pr_warning("Failed to cast into string: "
820 "%s(%s) is not a pointer nor array.\n",
821 dwarf_diename(vr_die), dwarf_diename(&type));
824 if (ret == DW_TAG_pointer_type) {
825 if (die_get_real_type(&type, &type) == NULL) {
826 pr_warning("Failed to get a type"
831 ref_ptr = &(*ref_ptr)->next;
832 /* Add new reference with offset +0 */
833 *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
834 if (*ref_ptr == NULL) {
835 pr_warning("Out of memory error\n");
839 if (!die_compare_name(&type, "char") &&
840 !die_compare_name(&type, "unsigned char")) {
841 pr_warning("Failed to cast into string: "
842 "%s is not (unsigned) char *.\n",
843 dwarf_diename(vr_die));
846 tvar->type = strdup(cast);
847 return (tvar->type == NULL) ? -ENOMEM : 0;
850 ret = die_get_byte_size(&type) * 8;
852 /* Check the bitwidth */
853 if (ret > MAX_BASIC_TYPE_BITS) {
854 pr_info("%s exceeds max-bitwidth."
855 " Cut down to %d bits.\n",
856 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
857 ret = MAX_BASIC_TYPE_BITS;
860 ret = snprintf(buf, 16, "%c%d",
861 die_is_signed_type(&type) ? 's' : 'u', ret);
862 if (ret < 0 || ret >= 16) {
865 pr_warning("Failed to convert variable type: %s\n",
869 tvar->type = strdup(buf);
870 if (tvar->type == NULL)
876 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
877 struct perf_probe_arg_field *field,
878 struct probe_trace_arg_ref **ref_ptr,
881 struct probe_trace_arg_ref *ref = *ref_ptr;
886 pr_debug("converting %s in %s\n", field->name, varname);
887 if (die_get_real_type(vr_die, &type) == NULL) {
888 pr_warning("Failed to get the type of %s.\n", varname);
891 pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
892 tag = dwarf_tag(&type);
894 if (field->name[0] == '[' &&
895 (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
897 /* Save original type for next field */
898 memcpy(die_mem, &type, sizeof(*die_mem));
899 /* Get the type of this array */
900 if (die_get_real_type(&type, &type) == NULL) {
901 pr_warning("Failed to get the type of %s.\n", varname);
904 pr_debug2("Array real type: (%x)\n",
905 (unsigned)dwarf_dieoffset(&type));
906 if (tag == DW_TAG_pointer_type) {
907 ref = zalloc(sizeof(struct probe_trace_arg_ref));
911 (*ref_ptr)->next = ref;
915 ref->offset += die_get_byte_size(&type) * field->index;
917 /* Save vr_die for converting types */
918 memcpy(die_mem, vr_die, sizeof(*die_mem));
920 } else if (tag == DW_TAG_pointer_type) {
921 /* Check the pointer and dereference */
923 pr_err("Semantic error: %s must be referred by '->'\n",
927 /* Get the type pointed by this pointer */
928 if (die_get_real_type(&type, &type) == NULL) {
929 pr_warning("Failed to get the type of %s.\n", varname);
932 /* Verify it is a data structure */
933 if (dwarf_tag(&type) != DW_TAG_structure_type) {
934 pr_warning("%s is not a data structure.\n", varname);
938 ref = zalloc(sizeof(struct probe_trace_arg_ref));
942 (*ref_ptr)->next = ref;
946 /* Verify it is a data structure */
947 if (tag != DW_TAG_structure_type) {
948 pr_warning("%s is not a data structure.\n", varname);
951 if (field->name[0] == '[') {
952 pr_err("Semantic error: %s is not a pointor"
953 " nor array.\n", varname);
957 pr_err("Semantic error: %s must be referred by '.'\n",
962 pr_warning("Structure on a register is not "
968 if (die_find_member(&type, field->name, die_mem) == NULL) {
969 pr_warning("%s(tyep:%s) has no member %s.\n", varname,
970 dwarf_diename(&type), field->name);
974 /* Get the offset of the field */
975 ret = die_get_data_member_location(die_mem, &offs);
977 pr_warning("Failed to get the offset of %s.\n", field->name);
980 ref->offset += (long)offs;
983 /* Converting next field */
985 return convert_variable_fields(die_mem, field->name,
986 field->next, &ref, die_mem);
991 /* Show a variables in kprobe event format */
992 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
997 pr_debug("Converting variable %s into trace event.\n",
998 dwarf_diename(vr_die));
1000 ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
1003 pr_err("Failed to find the location of %s at this address.\n"
1004 " Perhaps, it has been optimized out.\n", pf->pvar->var);
1005 else if (ret == -ENOTSUP)
1006 pr_err("Sorry, we don't support this variable location yet.\n");
1007 else if (pf->pvar->field) {
1008 ret = convert_variable_fields(vr_die, pf->pvar->var,
1009 pf->pvar->field, &pf->tvar->ref,
1014 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
1015 /* *expr will be cached in libdw. Don't free it. */
1019 /* Find a variable in a subprogram die */
1020 static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
1022 Dwarf_Die vr_die, *scopes;
1026 if (!is_c_varname(pf->pvar->var)) {
1027 /* Copy raw parameters */
1028 pf->tvar->value = strdup(pf->pvar->var);
1029 if (pf->tvar->value == NULL)
1031 if (pf->pvar->type) {
1032 pf->tvar->type = strdup(pf->pvar->type);
1033 if (pf->tvar->type == NULL)
1036 if (pf->pvar->name) {
1037 pf->tvar->name = strdup(pf->pvar->name);
1038 if (pf->tvar->name == NULL)
1041 pf->tvar->name = NULL;
1046 pf->tvar->name = strdup(pf->pvar->name);
1048 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
1051 ptr = strchr(buf, ':'); /* Change type separator to _ */
1054 pf->tvar->name = strdup(buf);
1056 if (pf->tvar->name == NULL)
1059 pr_debug("Searching '%s' variable in context.\n",
1061 /* Search child die for local variables and parameters. */
1062 if (die_find_variable_at(sp_die, pf->pvar->var, pf->addr, &vr_die))
1063 ret = convert_variable(&vr_die, pf);
1065 /* Search upper class */
1066 nscopes = dwarf_getscopes_die(sp_die, &scopes);
1067 while (nscopes-- > 1) {
1068 pr_debug("Searching variables in %s\n",
1069 dwarf_diename(&scopes[nscopes]));
1070 /* We should check this scope, so give dummy address */
1071 if (die_find_variable_at(&scopes[nscopes],
1074 ret = convert_variable(&vr_die, pf);
1084 pr_warning("Failed to find '%s' in this function.\n",
1089 /* Convert subprogram DIE to trace point */
1090 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr,
1091 bool retprobe, struct probe_trace_point *tp)
1096 /* Copy the name of probe point */
1097 name = dwarf_diename(sp_die);
1099 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
1100 pr_warning("Failed to get entry address of %s\n",
1101 dwarf_diename(sp_die));
1104 tp->symbol = strdup(name);
1105 if (tp->symbol == NULL)
1107 tp->offset = (unsigned long)(paddr - eaddr);
1109 /* This function has no name. */
1110 tp->offset = (unsigned long)paddr;
1112 /* Return probe must be on the head of a subprogram */
1114 if (eaddr != paddr) {
1115 pr_warning("Return probe must be on the head of"
1116 " a real function.\n");
1119 tp->retprobe = true;
1125 /* Call probe_finder callback with real subprogram DIE */
1126 static int call_probe_finder(Dwarf_Die *sp_die, struct probe_finder *pf)
1129 Dwarf_Attribute fb_attr;
1133 /* If no real subprogram, find a real one */
1134 if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
1135 sp_die = die_find_real_subprogram(&pf->cu_die,
1136 pf->addr, &die_mem);
1138 pr_warning("Failed to find probe point in any "
1144 /* Get the frame base attribute/ops */
1145 dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
1146 ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
1147 if (ret <= 0 || nops == 0) {
1149 #if _ELFUTILS_PREREQ(0, 142)
1150 } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
1153 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
1154 dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
1155 pr_warning("Failed to get call frame on 0x%jx\n",
1156 (uintmax_t)pf->addr);
1162 /* Call finder's callback handler */
1163 ret = pf->callback(sp_die, pf);
1165 /* *pf->fb_ops will be cached in libdw. Don't free it. */
1171 static int probe_point_line_walker(const char *fname, int lineno,
1172 Dwarf_Addr addr, void *data)
1174 struct probe_finder *pf = data;
1177 if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
1181 ret = call_probe_finder(NULL, pf);
1183 /* Continue if no error, because the line will be in inline function */
1184 return ret < 0 ?: 0;
1187 /* Find probe point from its line number */
1188 static int find_probe_point_by_line(struct probe_finder *pf)
1190 return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
1193 /* Find lines which match lazy pattern */
1194 static int find_lazy_match_lines(struct list_head *head,
1195 const char *fname, const char *pat)
1197 char *fbuf, *p1, *p2;
1198 int fd, line, nlines = -1;
1201 fd = open(fname, O_RDONLY);
1203 pr_warning("Failed to open %s: %s\n", fname, strerror(-fd));
1207 if (fstat(fd, &st) < 0) {
1208 pr_warning("Failed to get the size of %s: %s\n",
1209 fname, strerror(errno));
1215 fbuf = malloc(st.st_size + 2);
1218 if (read(fd, fbuf, st.st_size) < 0) {
1219 pr_warning("Failed to read %s: %s\n", fname, strerror(errno));
1223 fbuf[st.st_size] = '\n'; /* Dummy line */
1224 fbuf[st.st_size + 1] = '\0';
1228 while ((p2 = strchr(p1, '\n')) != NULL) {
1230 if (strlazymatch(p1, pat)) {
1231 line_list__add_line(head, line);
1244 static int probe_point_lazy_walker(const char *fname, int lineno,
1245 Dwarf_Addr addr, void *data)
1247 struct probe_finder *pf = data;
1250 if (!line_list__has_line(&pf->lcache, lineno) ||
1251 strtailcmp(fname, pf->fname) != 0)
1254 pr_debug("Probe line found: line:%d addr:0x%llx\n",
1255 lineno, (unsigned long long)addr);
1257 ret = call_probe_finder(NULL, pf);
1260 * Continue if no error, because the lazy pattern will match
1263 return ret < 0 ?: 0;
1266 /* Find probe points from lazy pattern */
1267 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
1271 if (list_empty(&pf->lcache)) {
1272 /* Matching lazy line pattern */
1273 ret = find_lazy_match_lines(&pf->lcache, pf->fname,
1274 pf->pev->point.lazy_line);
1276 pr_debug("No matched lines found in %s.\n", pf->fname);
1282 return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
1285 /* Callback parameter with return value */
1286 struct dwarf_callback_param {
1291 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
1293 struct dwarf_callback_param *param = data;
1294 struct probe_finder *pf = param->data;
1295 struct perf_probe_point *pp = &pf->pev->point;
1299 param->retval = find_probe_point_lazy(in_die, pf);
1301 /* Get probe address */
1302 if (dwarf_entrypc(in_die, &addr) != 0) {
1303 pr_warning("Failed to get entry address of %s.\n",
1304 dwarf_diename(in_die));
1305 param->retval = -ENOENT;
1306 return DWARF_CB_ABORT;
1309 pf->addr += pp->offset;
1310 pr_debug("found inline addr: 0x%jx\n",
1311 (uintmax_t)pf->addr);
1313 param->retval = call_probe_finder(in_die, pf);
1314 if (param->retval < 0)
1315 return DWARF_CB_ABORT;
1321 /* Search function from function name */
1322 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
1324 struct dwarf_callback_param *param = data;
1325 struct probe_finder *pf = param->data;
1326 struct perf_probe_point *pp = &pf->pev->point;
1328 /* Check tag and diename */
1329 if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
1330 !die_compare_name(sp_die, pp->function))
1333 pf->fname = dwarf_decl_file(sp_die);
1334 if (pp->line) { /* Function relative line */
1335 dwarf_decl_line(sp_die, &pf->lno);
1336 pf->lno += pp->line;
1337 param->retval = find_probe_point_by_line(pf);
1338 } else if (!dwarf_func_inline(sp_die)) {
1341 param->retval = find_probe_point_lazy(sp_die, pf);
1343 if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
1344 pr_warning("Failed to get entry address of "
1345 "%s.\n", dwarf_diename(sp_die));
1346 param->retval = -ENOENT;
1347 return DWARF_CB_ABORT;
1349 pf->addr += pp->offset;
1350 /* TODO: Check the address in this function */
1351 param->retval = call_probe_finder(sp_die, pf);
1354 struct dwarf_callback_param _param = {.data = (void *)pf,
1356 /* Inlined function: search instances */
1357 dwarf_func_inline_instances(sp_die, probe_point_inline_cb,
1359 param->retval = _param.retval;
1362 return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1365 static int find_probe_point_by_func(struct probe_finder *pf)
1367 struct dwarf_callback_param _param = {.data = (void *)pf,
1369 dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1370 return _param.retval;
1373 /* Find probe points from debuginfo */
1374 static int find_probes(int fd, struct probe_finder *pf)
1376 struct perf_probe_point *pp = &pf->pev->point;
1377 Dwarf_Off off, noff;
1382 Dwarf_Addr bias; /* Currently ignored */
1385 dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
1387 pr_warning("No debug information found in the vmlinux - "
1388 "please rebuild with CONFIG_DEBUG_INFO=y.\n");
1392 #if _ELFUTILS_PREREQ(0, 142)
1393 /* Get the call frame information from this dwarf */
1394 pf->cfi = dwarf_getcfi(dbg);
1398 line_list__init(&pf->lcache);
1399 /* Loop on CUs (Compilation Unit) */
1400 while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) &&
1402 /* Get the DIE(Debugging Information Entry) of this CU */
1403 diep = dwarf_offdie(dbg, off + cuhl, &pf->cu_die);
1407 /* Check if target file is included. */
1409 pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1413 if (!pp->file || pf->fname) {
1415 ret = find_probe_point_by_func(pf);
1416 else if (pp->lazy_line)
1417 ret = find_probe_point_lazy(NULL, pf);
1420 ret = find_probe_point_by_line(pf);
1425 line_list__free(&pf->lcache);
1432 /* Add a found probe point into trace event list */
1433 static int add_probe_trace_event(Dwarf_Die *sp_die, struct probe_finder *pf)
1435 struct trace_event_finder *tf =
1436 container_of(pf, struct trace_event_finder, pf);
1437 struct probe_trace_event *tev;
1440 /* Check number of tevs */
1441 if (tf->ntevs == tf->max_tevs) {
1442 pr_warning("Too many( > %d) probe point found.\n",
1446 tev = &tf->tevs[tf->ntevs++];
1448 ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
1453 pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1456 /* Find each argument */
1457 tev->nargs = pf->pev->nargs;
1458 tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1459 if (tev->args == NULL)
1461 for (i = 0; i < pf->pev->nargs; i++) {
1462 pf->pvar = &pf->pev->args[i];
1463 pf->tvar = &tev->args[i];
1464 ret = find_variable(sp_die, pf);
1472 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1473 int find_probe_trace_events(int fd, struct perf_probe_event *pev,
1474 struct probe_trace_event **tevs, int max_tevs)
1476 struct trace_event_finder tf = {
1477 .pf = {.pev = pev, .callback = add_probe_trace_event},
1478 .max_tevs = max_tevs};
1481 /* Allocate result tevs array */
1482 *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
1489 ret = find_probes(fd, &tf.pf);
1496 return (ret < 0) ? ret : tf.ntevs;
1499 #define MAX_VAR_LEN 64
1501 /* Collect available variables in this scope */
1502 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1504 struct available_var_finder *af = data;
1505 struct variable_list *vl;
1506 char buf[MAX_VAR_LEN];
1509 vl = &af->vls[af->nvls - 1];
1511 tag = dwarf_tag(die_mem);
1512 if (tag == DW_TAG_formal_parameter ||
1513 tag == DW_TAG_variable) {
1514 ret = convert_variable_location(die_mem, af->pf.addr,
1515 af->pf.fb_ops, NULL);
1517 ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1518 pr_debug2("Add new var: %s\n", buf);
1520 strlist__add(vl->vars, buf);
1524 if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1525 return DIE_FIND_CB_CONTINUE;
1527 return DIE_FIND_CB_SIBLING;
1530 /* Add a found vars into available variables list */
1531 static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf)
1533 struct available_var_finder *af =
1534 container_of(pf, struct available_var_finder, pf);
1535 struct variable_list *vl;
1536 Dwarf_Die die_mem, *scopes = NULL;
1539 /* Check number of tevs */
1540 if (af->nvls == af->max_vls) {
1541 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1544 vl = &af->vls[af->nvls++];
1546 ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
1551 pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1554 /* Find local variables */
1555 vl->vars = strlist__new(true, NULL);
1556 if (vl->vars == NULL)
1559 die_find_child(sp_die, collect_variables_cb, (void *)af, &die_mem);
1561 /* Find external variables */
1564 /* Don't need to search child DIE for externs. */
1566 nscopes = dwarf_getscopes_die(sp_die, &scopes);
1567 while (nscopes-- > 1)
1568 die_find_child(&scopes[nscopes], collect_variables_cb,
1569 (void *)af, &die_mem);
1574 if (strlist__empty(vl->vars)) {
1575 strlist__delete(vl->vars);
1582 /* Find available variables at given probe point */
1583 int find_available_vars_at(int fd, struct perf_probe_event *pev,
1584 struct variable_list **vls, int max_vls,
1587 struct available_var_finder af = {
1588 .pf = {.pev = pev, .callback = add_available_vars},
1589 .max_vls = max_vls, .externs = externs};
1592 /* Allocate result vls array */
1593 *vls = zalloc(sizeof(struct variable_list) * max_vls);
1600 ret = find_probes(fd, &af.pf);
1602 /* Free vlist for error */
1604 if (af.vls[af.nvls].point.symbol)
1605 free(af.vls[af.nvls].point.symbol);
1606 if (af.vls[af.nvls].vars)
1607 strlist__delete(af.vls[af.nvls].vars);
1614 return (ret < 0) ? ret : af.nvls;
1617 /* Reverse search */
1618 int find_perf_probe_point(unsigned long addr, struct perf_probe_point *ppt)
1620 Dwarf_Die cudie, spdie, indie;
1624 Dwarf_Addr laddr, eaddr, bias = 0;
1626 int lineno, ret = 0;
1629 /* Open the live linux kernel */
1630 dbg = dwfl_init_live_kernel_dwarf(addr, &dwfl, &bias);
1632 pr_warning("No debug information found in the vmlinux - "
1633 "please rebuild with CONFIG_DEBUG_INFO=y.\n");
1638 /* Adjust address with bias */
1641 if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr - bias, &cudie)) {
1642 pr_warning("Failed to find debug information for address %lx\n",
1648 /* Find a corresponding line */
1649 line = dwarf_getsrc_die(&cudie, (Dwarf_Addr)addr);
1651 if (dwarf_lineaddr(line, &laddr) == 0 &&
1652 (Dwarf_Addr)addr == laddr &&
1653 dwarf_lineno(line, &lineno) == 0) {
1654 tmp = dwarf_linesrc(line, NULL, NULL);
1657 ppt->file = strdup(tmp);
1658 if (ppt->file == NULL) {
1667 /* Find a corresponding function */
1668 if (die_find_real_subprogram(&cudie, (Dwarf_Addr)addr, &spdie)) {
1669 tmp = dwarf_diename(&spdie);
1670 if (!tmp || dwarf_entrypc(&spdie, &eaddr) != 0)
1674 if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr,
1676 /* addr in an inline function */
1677 tmp = dwarf_diename(&indie);
1680 ret = dwarf_decl_line(&indie, &lineno);
1682 if (eaddr == addr) { /* Function entry */
1686 ret = dwarf_decl_line(&spdie, &lineno);
1689 /* Make a relative line number */
1690 ppt->line -= lineno;
1694 /* We don't have a line number, let's use offset */
1695 ppt->offset = addr - (unsigned long)eaddr;
1697 ppt->function = strdup(tmp);
1698 if (ppt->function == NULL) {
1709 ret = found ? 1 : 0;
1713 /* Add a line and store the src path */
1714 static int line_range_add_line(const char *src, unsigned int lineno,
1715 struct line_range *lr)
1717 /* Copy source path */
1719 lr->path = strdup(src);
1720 if (lr->path == NULL)
1723 return line_list__add_line(&lr->line_list, lineno);
1726 static int line_range_walk_cb(const char *fname, int lineno,
1727 Dwarf_Addr addr __used,
1730 struct line_finder *lf = data;
1732 if ((strtailcmp(fname, lf->fname) != 0) ||
1733 (lf->lno_s > lineno || lf->lno_e < lineno))
1736 if (line_range_add_line(fname, lineno, lf->lr) < 0)
1742 /* Find line range from its line number */
1743 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1747 ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1751 if (!list_empty(&lf->lr->line_list))
1752 ret = lf->found = 1;
1754 ret = 0; /* Lines are not found */
1757 lf->lr->path = NULL;
1762 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1764 struct dwarf_callback_param *param = data;
1766 param->retval = find_line_range_by_line(in_die, param->data);
1767 return DWARF_CB_ABORT; /* No need to find other instances */
1770 /* Search function from function name */
1771 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1773 struct dwarf_callback_param *param = data;
1774 struct line_finder *lf = param->data;
1775 struct line_range *lr = lf->lr;
1777 if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
1778 die_compare_name(sp_die, lr->function)) {
1779 lf->fname = dwarf_decl_file(sp_die);
1780 dwarf_decl_line(sp_die, &lr->offset);
1781 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1782 lf->lno_s = lr->offset + lr->start;
1783 if (lf->lno_s < 0) /* Overflow */
1784 lf->lno_s = INT_MAX;
1785 lf->lno_e = lr->offset + lr->end;
1786 if (lf->lno_e < 0) /* Overflow */
1787 lf->lno_e = INT_MAX;
1788 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1789 lr->start = lf->lno_s;
1790 lr->end = lf->lno_e;
1791 if (dwarf_func_inline(sp_die)) {
1792 struct dwarf_callback_param _param;
1793 _param.data = (void *)lf;
1795 dwarf_func_inline_instances(sp_die,
1796 line_range_inline_cb,
1798 param->retval = _param.retval;
1800 param->retval = find_line_range_by_line(sp_die, lf);
1801 return DWARF_CB_ABORT;
1806 static int find_line_range_by_func(struct line_finder *lf)
1808 struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1809 dwarf_getfuncs(&lf->cu_die, line_range_search_cb, ¶m, 0);
1810 return param.retval;
1813 int find_line_range(int fd, struct line_range *lr)
1815 struct line_finder lf = {.lr = lr, .found = 0};
1817 Dwarf_Off off = 0, noff;
1822 Dwarf_Addr bias; /* Currently ignored */
1823 const char *comp_dir;
1825 dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
1827 pr_warning("No debug information found in the vmlinux - "
1828 "please rebuild with CONFIG_DEBUG_INFO=y.\n");
1832 /* Loop on CUs (Compilation Unit) */
1833 while (!lf.found && ret >= 0) {
1834 if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
1837 /* Get the DIE(Debugging Information Entry) of this CU */
1838 diep = dwarf_offdie(dbg, off + cuhl, &lf.cu_die);
1842 /* Check if target file is included. */
1844 lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1848 if (!lr->file || lf.fname) {
1850 ret = find_line_range_by_func(&lf);
1852 lf.lno_s = lr->start;
1854 ret = find_line_range_by_line(NULL, &lf);
1860 /* Store comp_dir */
1862 comp_dir = cu_get_comp_dir(&lf.cu_die);
1864 lr->comp_dir = strdup(comp_dir);
1870 pr_debug("path: %s\n", lr->path);
1872 return (ret < 0) ? ret : lf.found;