/* Search function from function name */ static int probe_point_search_cb(Dwarf_Die *sp_die, void *data) { struct dwarf_callback_param *param = data; struct probe_finder *pf = param->data; struct perf_probe_point *pp = &pf->pev->point; /* Check tag and diename */ if (dwarf_tag(sp_die) != DW_TAG_subprogram || !die_compare_name(sp_die, pp->function)) return DWARF_CB_OK; pf->fname = dwarf_decl_file(sp_die); if (pp->line) { /* Function relative line */ dwarf_decl_line(sp_die, &pf->lno); pf->lno += pp->line; param->retval = find_probe_point_by_line(pf); } else if (!dwarf_func_inline(sp_die)) { /* Real function */ if (pp->lazy_line) param->retval = find_probe_point_lazy(sp_die, pf); else { if (dwarf_entrypc(sp_die, &pf->addr) != 0) { pr_warning("Failed to get entry address of " "%s.\n", dwarf_diename(sp_die)); param->retval = -ENOENT; return DWARF_CB_ABORT; } pf->addr += pp->offset; /* TODO: Check the address in this function */ param->retval = call_probe_finder(sp_die, pf); } } else { struct dwarf_callback_param _param = {.data = (void *)pf, .retval = 0}; /* Inlined function: search instances */ dwarf_func_inline_instances(sp_die, probe_point_inline_cb, &_param); param->retval = _param.retval; } return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */ } static int find_probe_point_by_func(struct probe_finder *pf) { struct dwarf_callback_param _param = {.data = (void *)pf, .retval = 0}; dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0); return _param.retval; } /* Find probe points from debuginfo */ static int find_probes(int fd, struct probe_finder *pf) { struct perf_probe_point *pp = &pf->pev->point; Dwarf_Off off, noff; size_t cuhl; Dwarf_Die *diep; Dwarf *dbg = NULL; Dwfl *dwfl; Dwarf_Addr bias; /* Currently ignored */ int ret = 0; dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias); if (!dbg) { pr_warning("No debug information found in the vmlinux - " "please rebuild with CONFIG_DEBUG_INFO=y.\n"); return -EBADF; } #if _ELFUTILS_PREREQ(0, 142) /* Get the call frame information from this dwarf */ pf->cfi = dwarf_getcfi(dbg); #endif off = 0; line_list__init(&pf->lcache); /* Loop on CUs (Compilation Unit) */ while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL)) { /* Get the DIE(Debugging Information Entry) of this CU */ diep = dwarf_offdie(dbg, off + cuhl, &pf->cu_die); if (!diep) continue; /* Check if target file is included. */ if (pp->file) pf->fname = cu_find_realpath(&pf->cu_die, pp->file); else pf->fname = NULL; if (!pp->file || pf->fname) { if (pp->function) ret = find_probe_point_by_func(pf); else if (pp->lazy_line) ret = find_probe_point_lazy(NULL, pf); else { pf->lno = pp->line; ret = find_probe_point_by_line(pf); } if (ret < 0) break; } off = noff; } line_list__free(&pf->lcache); if (dwfl) dwfl_end(dwfl); return ret; } /* Add a found probe point into trace event list */ static int add_probe_trace_event(Dwarf_Die *sp_die, struct probe_finder *pf) { struct trace_event_finder *tf = container_of(pf, struct trace_event_finder, pf); struct probe_trace_event *tev; int ret, i; /* Check number of tevs */ if (tf->ntevs == tf->max_tevs) { pr_warning("Too many( > %d) probe point found.\n", tf->max_tevs); return -ERANGE; } tev = &tf->tevs[tf->ntevs++]; ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe, &tev->point); if (ret < 0) return ret; pr_debug("Probe point found: %s+%lu\n", tev->point.symbol, tev->point.offset); /* Find each argument */ tev->nargs = pf->pev->nargs; tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs); if (tev->args == NULL) return -ENOMEM; for (i = 0; i < pf->pev->nargs; i++) { pf->pvar = &pf->pev->args[i]; pf->tvar = &tev->args[i]; ret = find_variable(sp_die, pf); if (ret != 0) return ret; } return 0; } /* Find probe_trace_events specified by perf_probe_event from debuginfo */ int find_probe_trace_events(int fd, struct perf_probe_event *pev, struct probe_trace_event **tevs, int max_tevs) { struct trace_event_finder tf = { .pf = {.pev = pev, .callback = add_probe_trace_event}, .max_tevs = max_tevs}; int ret; /* Allocate result tevs array */ *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs); if (*tevs == NULL) return -ENOMEM; tf.tevs = *tevs; tf.ntevs = 0; ret = find_probes(fd, &tf.pf); if (ret < 0) { free(*tevs); *tevs = NULL; return ret; } return (ret < 0) ? ret : tf.ntevs; } #define MAX_VAR_LEN 64 /* Collect available variables in this scope */ static int collect_variables_cb(Dwarf_Die *die_mem, void *data) { struct available_var_finder *af = data; struct variable_list *vl; char buf[MAX_VAR_LEN]; int tag, ret; vl = &af->vls[af->nvls - 1]; tag = dwarf_tag(die_mem); if (tag == DW_TAG_formal_parameter || tag == DW_TAG_variable) { ret = convert_variable_location(die_mem, af->pf.addr, af->pf.fb_ops, NULL); if (ret == 0) { ret = die_get_varname(die_mem, buf, MAX_VAR_LEN); pr_debug2("Add new var: %s\n", buf); if (ret > 0) strlist__add(vl->vars, buf); } } if (af->child && dwarf_haspc(die_mem, af->pf.addr)) return DIE_FIND_CB_CONTINUE; else return DIE_FIND_CB_SIBLING; } /* Add a found vars into available variables list */ static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf) { struct available_var_finder *af = container_of(pf, struct available_var_finder, pf); struct variable_list *vl; Dwarf_Die die_mem, *scopes = NULL; int ret, nscopes; /* Check number of tevs */ if (af->nvls == af->max_vls) { pr_warning("Too many( > %d) probe point found.\n", af->max_vls); return -ERANGE; } vl = &af->vls[af->nvls++]; ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe, &vl->point); if (ret < 0) return ret; pr_debug("Probe point found: %s+%lu\n", vl->point.symbol, vl->point.offset); /* Find local variables */ vl->vars = strlist__new(true, NULL); if (vl->vars == NULL) return -ENOMEM; af->child = true; die_find_child(sp_die, collect_variables_cb, (void *)af, &die_mem); /* Find external variables */ if (!af->externs) goto out; /* Don't need to search child DIE for externs. */ af->child = false; nscopes = dwarf_getscopes_die(sp_die, &scopes); while (nscopes-- > 1) die_find_child(&scopes[nscopes], collect_variables_cb, (void *)af, &die_mem); if (scopes) free(scopes); out: if (strlist__empty(vl->vars)) { strlist__delete(vl->vars); vl->vars = NULL; } return ret; } /* Find available variables at given probe point */ int find_available_vars_at(int fd, struct perf_probe_event *pev, struct variable_list **vls, int max_vls, bool externs) { struct available_var_finder af = { .pf = {.pev = pev, .callback = add_available_vars}, .max_vls = max_vls, .externs = externs}; int ret; /* Allocate result vls array */ *vls = zalloc(sizeof(struct variable_list) * max_vls); if (*vls == NULL) return -ENOMEM; af.vls = *vls; af.nvls = 0; ret = find_probes(fd, &af.pf); if (ret < 0) { /* Free vlist for error */ while (af.nvls--) { if (af.vls[af.nvls].point.symbol) free(af.vls[af.nvls].point.symbol); if (af.vls[af.nvls].vars) strlist__delete(af.vls[af.nvls].vars); } free(af.vls); *vls = NULL; return ret; } return (ret < 0) ? ret : af.nvls; }
static int find_probe_point_by_func(struct probe_finder *pf) { struct dwarf_callback_param _param = {.data = (void *)pf, .retval = 0}; dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0); return _param.retval; } struct pubname_callback_param { char *function; char *file; Dwarf_Die *cu_die; Dwarf_Die *sp_die; int found; }; static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data) { struct pubname_callback_param *param = data; if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) { if (dwarf_tag(param->sp_die) != DW_TAG_subprogram) return DWARF_CB_OK; if (die_compare_name(param->sp_die, param->function)) { if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die)) return DWARF_CB_OK; if (param->file && strtailcmp(param->file, dwarf_decl_file(param->sp_die))) return DWARF_CB_OK; param->found = 1; return DWARF_CB_ABORT; } } return DWARF_CB_OK; } /* Find probe points from debuginfo */ static int debuginfo__find_probes(struct debuginfo *self, struct probe_finder *pf) { struct perf_probe_point *pp = &pf->pev->point; Dwarf_Off off, noff; size_t cuhl; Dwarf_Die *diep; int ret = 0; #if _ELFUTILS_PREREQ(0, 142) /* Get the call frame information from this dwarf */ pf->cfi = dwarf_getcfi(self->dbg); #endif off = 0; line_list__init(&pf->lcache); /* Fastpath: lookup by function name from .debug_pubnames section */ if (pp->function) { struct pubname_callback_param pubname_param = { .function = pp->function, .file = pp->file, .cu_die = &pf->cu_die, .sp_die = &pf->sp_die, .found = 0, }; struct dwarf_callback_param probe_param = { .data = pf, }; dwarf_getpubnames(self->dbg, pubname_search_cb, &pubname_param, 0); if (pubname_param.found) { ret = probe_point_search_cb(&pf->sp_die, &probe_param); if (ret) goto found; } } /* Loop on CUs (Compilation Unit) */ while (!dwarf_nextcu(self->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) { /* Get the DIE(Debugging Information Entry) of this CU */ diep = dwarf_offdie(self->dbg, off + cuhl, &pf->cu_die); if (!diep) continue; /* Check if target file is included. */ if (pp->file) pf->fname = cu_find_realpath(&pf->cu_die, pp->file); else pf->fname = NULL; if (!pp->file || pf->fname) { if (pp->function) ret = find_probe_point_by_func(pf); else if (pp->lazy_line) ret = find_probe_point_lazy(NULL, pf); else { pf->lno = pp->line; ret = find_probe_point_by_line(pf); } if (ret < 0) break; } off = noff; } found: line_list__free(&pf->lcache); return ret; } /* Add a found probe point into trace event list */ static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf) { struct trace_event_finder *tf = container_of(pf, struct trace_event_finder, pf); struct probe_trace_event *tev; int ret, i; /* Check number of tevs */ if (tf->ntevs == tf->max_tevs) { pr_warning("Too many( > %d) probe point found.\n", tf->max_tevs); return -ERANGE; } tev = &tf->tevs[tf->ntevs++]; /* Trace point should be converted from subprogram DIE */ ret = convert_to_trace_point(&pf->sp_die, pf->addr, pf->pev->point.retprobe, &tev->point); if (ret < 0) return ret; pr_debug("Probe point found: %s+%lu\n", tev->point.symbol, tev->point.offset); /* Find each argument */ tev->nargs = pf->pev->nargs; tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs); if (tev->args == NULL) return -ENOMEM; for (i = 0; i < pf->pev->nargs; i++) { pf->pvar = &pf->pev->args[i]; pf->tvar = &tev->args[i]; /* Variable should be found from scope DIE */ ret = find_variable(sc_die, pf); if (ret != 0) return ret; } return 0; } /* Find probe_trace_events specified by perf_probe_event from debuginfo */ int debuginfo__find_trace_events(struct debuginfo *self, struct perf_probe_event *pev, struct probe_trace_event **tevs, int max_tevs) { struct trace_event_finder tf = { .pf = {.pev = pev, .callback = add_probe_trace_event}, .max_tevs = max_tevs}; int ret; /* Allocate result tevs array */ *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs); if (*tevs == NULL) return -ENOMEM; tf.tevs = *tevs; tf.ntevs = 0; ret = debuginfo__find_probes(self, &tf.pf); if (ret < 0) { free(*tevs); *tevs = NULL; return ret; } return (ret < 0) ? ret : tf.ntevs; } #define MAX_VAR_LEN 64 /* Collect available variables in this scope */ static int collect_variables_cb(Dwarf_Die *die_mem, void *data) { struct available_var_finder *af = data; struct variable_list *vl; char buf[MAX_VAR_LEN]; int tag, ret; vl = &af->vls[af->nvls - 1]; tag = dwarf_tag(die_mem); if (tag == DW_TAG_formal_parameter || tag == DW_TAG_variable) { ret = convert_variable_location(die_mem, af->pf.addr, af->pf.fb_ops, NULL); if (ret == 0) { ret = die_get_varname(die_mem, buf, MAX_VAR_LEN); pr_debug2("Add new var: %s\n", buf); if (ret > 0) strlist__add(vl->vars, buf); } } if (af->child && dwarf_haspc(die_mem, af->pf.addr)) return DIE_FIND_CB_CONTINUE; else return DIE_FIND_CB_SIBLING; } /* Add a found vars into available variables list */ static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf) { struct available_var_finder *af = container_of(pf, struct available_var_finder, pf); struct variable_list *vl; Dwarf_Die die_mem; int ret; /* Check number of tevs */ if (af->nvls == af->max_vls) { pr_warning("Too many( > %d) probe point found.\n", af->max_vls); return -ERANGE; } vl = &af->vls[af->nvls++]; /* Trace point should be converted from subprogram DIE */ ret = convert_to_trace_point(&pf->sp_die, pf->addr, pf->pev->point.retprobe, &vl->point); if (ret < 0) return ret; pr_debug("Probe point found: %s+%lu\n", vl->point.symbol, vl->point.offset); /* Find local variables */ vl->vars = strlist__new(true, NULL); if (vl->vars == NULL) return -ENOMEM; af->child = true; die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem); /* Find external variables */ if (!af->externs) goto out; /* Don't need to search child DIE for externs. */ af->child = false; die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem); out: if (strlist__empty(vl->vars)) { strlist__delete(vl->vars); vl->vars = NULL; } return ret; } /* Find available variables at given probe point */ int debuginfo__find_available_vars_at(struct debuginfo *self, struct perf_probe_event *pev, struct variable_list **vls, int max_vls, bool externs) { struct available_var_finder af = { .pf = {.pev = pev, .callback = add_available_vars}, .max_vls = max_vls, .externs = externs}; int ret; /* Allocate result vls array */ *vls = zalloc(sizeof(struct variable_list) * max_vls); if (*vls == NULL) return -ENOMEM; af.vls = *vls; af.nvls = 0; ret = debuginfo__find_probes(self, &af.pf); if (ret < 0) { /* Free vlist for error */ while (af.nvls--) { if (af.vls[af.nvls].point.symbol) free(af.vls[af.nvls].point.symbol); if (af.vls[af.nvls].vars) strlist__delete(af.vls[af.nvls].vars); } free(af.vls); *vls = NULL; return ret; } return (ret < 0) ? ret : af.nvls; }