/* die_find callback for inline function search */
static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
{
Dwarf_Addr *addr = data;
if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
dwarf_haspc(die_mem, *addr))
return DIE_FIND_CB_END;
return DIE_FIND_CB_CONTINUE;
}
static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
{
struct __addr_die_search_param *ad = data;
if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
dwarf_haspc(fn_die, ad->addr)) {
memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
return DWARF_CB_ABORT;
}
return DWARF_CB_OK;
}
/* die_find callback for non-inlined function search */
static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
{
struct __addr_die_search_param *ad = data;
/*
* Since a declaration entry doesn't has given pc, this always returns
* function definition entry.
*/
if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
dwarf_haspc(fn_die, ad->addr)) {
memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
return DWARF_CB_ABORT;
}
return DWARF_CB_OK;
}
BT_HIDDEN
int bt_dwarf_die_contains_addr(struct bt_dwarf_die *die, uint64_t addr,
bool *contains)
{
int ret;
ret = dwarf_haspc(die->dwarf_die, addr);
if (ret == -1) {
goto error;
}
*contains = (ret == 1);
return 0;
error:
return -1;
}
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;
}
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)
pf->cfi = dwarf_getcfi(self->dbg);
#endif
off = 0;
line_list__init(&pf->lcache);
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;
}
}
while (!dwarf_nextcu(self->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
diep = dwarf_offdie(self->dbg, off + cuhl, &pf->cu_die);
if (!diep)
continue;
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;
}
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;
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(&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);
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(sc_die, pf);
if (ret != 0)
return ret;
}
return 0;
}
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;
*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
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;
}
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;
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(&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);
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);
if (!af->externs)
goto out;
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;
}
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;
*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) {
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 *dbg,
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)
Elf *elf;
GElf_Ehdr ehdr;
GElf_Shdr shdr;
/* Get the call frame information from this dwarf */
elf = dwarf_getelf(dbg->dbg);
if (elf == NULL)
return -EINVAL;
if (gelf_getehdr(elf, &ehdr) == NULL)
return -EINVAL;
if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
shdr.sh_type == SHT_PROGBITS) {
pf->cfi = dwarf_getcfi_elf(elf);
} else {
pf->cfi = dwarf_getcfi(dbg->dbg);
}
#endif
off = 0;
pf->lcache = intlist__new(NULL);
if (!pf->lcache)
return -ENOMEM;
/* 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(dbg->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(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
/* Get the DIE(Debugging Information Entry) of this CU */
diep = dwarf_offdie(dbg->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(&pf->cu_die, pf);
else {
pf->lno = pp->line;
ret = find_probe_point_by_line(pf);
}
if (ret < 0)
break;
}
off = noff;
}
found:
intlist__delete(pf->lcache);
pf->lcache = NULL;
return ret;
}
struct local_vars_finder {
struct probe_finder *pf;
struct perf_probe_arg *args;
int max_args;
int nargs;
int ret;
};
/* Collect available variables in this scope */
static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
{
struct local_vars_finder *vf = data;
struct probe_finder *pf = vf->pf;
int tag;
tag = dwarf_tag(die_mem);
if (tag == DW_TAG_formal_parameter ||
tag == DW_TAG_variable) {
if (convert_variable_location(die_mem, vf->pf->addr,
vf->pf->fb_ops, &pf->sp_die,
NULL) == 0) {
vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
if (vf->args[vf->nargs].var == NULL) {
vf->ret = -ENOMEM;
return DIE_FIND_CB_END;
}
pr_debug(" %s", vf->args[vf->nargs].var);
vf->nargs++;
}
}
if (dwarf_haspc(die_mem, vf->pf->addr))
return DIE_FIND_CB_CONTINUE;
else
return DIE_FIND_CB_SIBLING;
}
static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
struct perf_probe_arg *args)
{
Dwarf_Die die_mem;
int i;
int n = 0;
struct local_vars_finder vf = {.pf = pf, .args = args,
.max_args = MAX_PROBE_ARGS, .ret = 0};
for (i = 0; i < pf->pev->nargs; i++) {
/* var never be NULL */
if (strcmp(pf->pev->args[i].var, "$vars") == 0) {
pr_debug("Expanding $vars into:");
vf.nargs = n;
/* Special local variables */
die_find_child(sc_die, copy_variables_cb, (void *)&vf,
&die_mem);
pr_debug(" (%d)\n", vf.nargs - n);
if (vf.ret < 0)
return vf.ret;
n = vf.nargs;
} else {
/* Copy normal argument */
args[n] = pf->pev->args[i];
n++;
}
}
return n;
}
/* 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;
struct perf_probe_arg *args;
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, tf->mod, 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);
/* Expand special probe argument if exist */
args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
if (args == NULL)
return -ENOMEM;
ret = expand_probe_args(sc_die, pf, args);
if (ret < 0)
goto end;
tev->nargs = ret;
tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
if (tev->args == NULL) {
ret = -ENOMEM;
goto end;
}
/* Find each argument */
for (i = 0; i < tev->nargs; i++) {
pf->pvar = &args[i];
pf->tvar = &tev->args[i];
/* Variable should be found from scope DIE */
ret = find_variable(sc_die, pf);
if (ret != 0)
break;
}
end:
free(args);
return ret;
}
/* Find probe_trace_events specified by perf_probe_event from debuginfo */
int debuginfo__find_trace_events(struct debuginfo *dbg,
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},
.mod = dbg->mod, .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(dbg, &tf.pf);
if (ret < 0) {
zfree(tevs);
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, &af->pf.sp_die,
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, af->mod, 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
* Return the number of found probe points. Return 0 if there is no
* matched probe point. Return <0 if an error occurs.
*/
int debuginfo__find_available_vars_at(struct debuginfo *dbg,
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},
.mod = dbg->mod,
.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(dbg, &af.pf);
if (ret < 0) {
/* Free vlist for error */
while (af.nvls--) {
zfree(&af.vls[af.nvls].point.symbol);
strlist__delete(af.vls[af.nvls].vars);
}
zfree(vls);
return ret;
}
return (ret < 0) ? ret : af.nvls;
}
/* Reverse search */
int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
struct perf_probe_point *ppt)
{
Dwarf_Die cudie, spdie, indie;
Dwarf_Addr _addr = 0, baseaddr = 0;
const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
int baseline = 0, lineno = 0, ret = 0;
/* Find cu die */
if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
pr_warning("Failed to find debug information for address %lx\n",
addr);
ret = -EINVAL;
goto end;
}
/* Find a corresponding line (filename and lineno) */
cu_find_lineinfo(&cudie, addr, &fname, &lineno);
/* Don't care whether it failed or not */
/* Find a corresponding function (name, baseline and baseaddr) */
if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
/* Get function entry information */
func = basefunc = dwarf_diename(&spdie);
if (!func ||
dwarf_entrypc(&spdie, &baseaddr) != 0 ||
dwarf_decl_line(&spdie, &baseline) != 0) {
lineno = 0;
goto post;
}
fname = dwarf_decl_file(&spdie);
if (addr == (unsigned long)baseaddr) {
/* Function entry - Relative line number is 0 */
lineno = baseline;
goto post;
}
/* Track down the inline functions step by step */
while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
&indie)) {
/* There is an inline function */
if (dwarf_entrypc(&indie, &_addr) == 0 &&
_addr == addr) {
/*
* addr is at an inline function entry.
* In this case, lineno should be the call-site
* line number. (overwrite lineinfo)
*/
lineno = die_get_call_lineno(&indie);
fname = die_get_call_file(&indie);
break;
} else {
/*
* addr is in an inline function body.
* Since lineno points one of the lines
* of the inline function, baseline should
* be the entry line of the inline function.
*/
tmp = dwarf_diename(&indie);
if (!tmp ||
dwarf_decl_line(&indie, &baseline) != 0)
break;
func = tmp;
spdie = indie;
}
}
/* Verify the lineno and baseline are in a same file */
tmp = dwarf_decl_file(&spdie);
if (!tmp || strcmp(tmp, fname) != 0)
lineno = 0;
}
post:
/* Make a relative line number or an offset */
if (lineno)
ppt->line = lineno - baseline;
else if (basefunc) {
ppt->offset = addr - (unsigned long)baseaddr;
func = basefunc;
}
/* Duplicate strings */
if (func) {
ppt->function = strdup(func);
if (ppt->function == NULL) {
ret = -ENOMEM;
goto end;
}
}
if (fname) {
ppt->file = strdup(fname);
if (ppt->file == NULL) {
zfree(&ppt->function);
ret = -ENOMEM;
goto end;
}
}
end:
if (ret == 0 && (fname || func))
ret = 1; /* Found a point */
return ret;
}
/* Add a line and store the src path */
static int line_range_add_line(const char *src, unsigned int lineno,
struct line_range *lr)
{
/* Copy source path */
if (!lr->path) {
lr->path = strdup(src);
if (lr->path == NULL)
return -ENOMEM;
}
return intlist__add(lr->line_list, lineno);
}
static int line_range_walk_cb(const char *fname, int lineno,
Dwarf_Addr addr __maybe_unused,
void *data)
{
struct line_finder *lf = data;
int err;
if ((strtailcmp(fname, lf->fname) != 0) ||
(lf->lno_s > lineno || lf->lno_e < lineno))
return 0;
err = line_range_add_line(fname, lineno, lf->lr);
if (err < 0 && err != -EEXIST)
return err;
return 0;
}
/* Find line range from its line number */
static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
{
int ret;
ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
/* Update status */
if (ret >= 0)
if (!intlist__empty(lf->lr->line_list))
ret = lf->found = 1;
else
ret = 0; /* Lines are not found */
else {
zfree(&lf->lr->path);
}
return ret;
}
/**
* die_walk_instances - Walk on instances of given DIE
* @or_die: an abstract original DIE
* @callback: a callback function which is called with instance DIE
* @data: user data
*
* Walk on the instances of give @in_die. @in_die must be an inlined function
* declartion. This returns the return value of @callback if it returns
* non-zero value, or -ENOENT if there is no instance.
*/
int die_walk_instances(Dwarf_Die *or_die, int (*callback)(Dwarf_Die *, void *),
void *data)
{
Dwarf_Die cu_die;
Dwarf_Die die_mem;
struct __instance_walk_param iwp = {
.addr = or_die->addr,
.callback = callback,
.data = data,
.retval = -ENOENT,
};
if (dwarf_diecu(or_die, &cu_die, NULL, NULL) == NULL)
return -ENOENT;
die_find_child(&cu_die, __die_walk_instances_cb, &iwp, &die_mem);
return iwp.retval;
}
/* Line walker internal parameters */
struct __line_walk_param {
bool recursive;
line_walk_callback_t callback;
void *data;
int retval;
};
static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
{
struct __line_walk_param *lw = data;
Dwarf_Addr addr = 0;
const char *fname;
int lineno;
if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
fname = die_get_call_file(in_die);
lineno = die_get_call_lineno(in_die);
if (fname && lineno > 0 && dwarf_entrypc(in_die, &addr) == 0) {
lw->retval = lw->callback(fname, lineno, addr, lw->data);
if (lw->retval != 0)
return DIE_FIND_CB_END;
}
}
if (!lw->recursive)
/* Don't need to search recursively */
return DIE_FIND_CB_SIBLING;
if (addr) {
fname = dwarf_decl_file(in_die);
if (fname && dwarf_decl_line(in_die, &lineno) == 0) {
lw->retval = lw->callback(fname, lineno, addr, lw->data);
if (lw->retval != 0)
return DIE_FIND_CB_END;
}
}
/* Continue to search nested inlined function call-sites */
return DIE_FIND_CB_CONTINUE;
}
/* Walk on lines of blocks included in given DIE */
static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
line_walk_callback_t callback, void *data)
{
struct __line_walk_param lw = {
.recursive = recursive,
.callback = callback,
.data = data,
.retval = 0,
};
Dwarf_Die die_mem;
Dwarf_Addr addr;
const char *fname;
int lineno;
/* Handle function declaration line */
fname = dwarf_decl_file(sp_die);
if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
dwarf_entrypc(sp_die, &addr) == 0) {
lw.retval = callback(fname, lineno, addr, data);
if (lw.retval != 0)
goto done;
}
die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
done:
return lw.retval;
}
static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
{
struct __line_walk_param *lw = data;
lw->retval = __die_walk_funclines(sp_die, true, lw->callback, lw->data);
if (lw->retval != 0)
return DWARF_CB_ABORT;
return DWARF_CB_OK;
}
/**
* die_walk_lines - Walk on lines inside given DIE
* @rt_die: a root DIE (CU, subprogram or inlined_subroutine)
* @callback: callback routine
* @data: user data
*
* Walk on all lines inside given @rt_die and call @callback on each line.
* If the @rt_die is a function, walk only on the lines inside the function,
* otherwise @rt_die must be a CU DIE.
* Note that this walks not only dwarf line list, but also function entries
* and inline call-site.
*/
int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
{
Dwarf_Lines *lines;
Dwarf_Line *line;
Dwarf_Addr addr;
const char *fname;
int lineno, ret = 0;
Dwarf_Die die_mem, *cu_die;
size_t nlines, i;
/* Get the CU die */
if (dwarf_tag(rt_die) != DW_TAG_compile_unit)
cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
else
cu_die = rt_die;
if (!cu_die) {
pr_debug2("Failed to get CU from given DIE.\n");
return -EINVAL;
}
/* Get lines list in the CU */
if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
pr_debug2("Failed to get source lines on this CU.\n");
return -ENOENT;
}
pr_debug2("Get %zd lines from this CU\n", nlines);
/* Walk on the lines on lines list */
for (i = 0; i < nlines; i++) {
line = dwarf_onesrcline(lines, i);
if (line == NULL ||
dwarf_lineno(line, &lineno) != 0 ||
dwarf_lineaddr(line, &addr) != 0) {
pr_debug2("Failed to get line info. "
"Possible error in debuginfo.\n");
continue;
}
/* Filter lines based on address */
if (rt_die != cu_die)
/*
* Address filtering
* The line is included in given function, and
* no inline block includes it.
*/
if (!dwarf_haspc(rt_die, addr) ||
die_find_inlinefunc(rt_die, addr, &die_mem))
continue;
/* Get source line */
fname = dwarf_linesrc(line, NULL, NULL);
ret = callback(fname, lineno, addr, data);
if (ret != 0)
return ret;
}
/*
* Dwarf lines doesn't include function declarations and inlined
* subroutines. We have to check functions list or given function.
*/
if (rt_die != cu_die)
/*
* Don't need walk functions recursively, because nested
* inlined functions don't have lines of the specified DIE.
*/
ret = __die_walk_funclines(rt_die, false, callback, data);
else {
struct __line_walk_param param = {
.callback = callback,
.data = data,
.retval = 0,
};
dwarf_getfuncs(cu_die, __die_walk_culines_cb, ¶m, 0);
ret = param.retval;
}
return ret;
}
struct __find_variable_param {
const char *name;
Dwarf_Addr addr;
};
static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
{
struct __find_variable_param *fvp = data;
Dwarf_Attribute attr;
int tag;
tag = dwarf_tag(die_mem);
if ((tag == DW_TAG_formal_parameter ||
tag == DW_TAG_variable) &&
die_compare_name(die_mem, fvp->name) &&
/* Does the DIE have location information or external instance? */
(dwarf_attr(die_mem, DW_AT_external, &attr) ||
dwarf_attr(die_mem, DW_AT_location, &attr)))
return DIE_FIND_CB_END;
if (dwarf_haspc(die_mem, fvp->addr))
return DIE_FIND_CB_CONTINUE;
else
return DIE_FIND_CB_SIBLING;
}
/**
* die_find_variable_at - Find a given name variable at given address
* @sp_die: a function DIE
* @name: variable name
* @addr: address
* @die_mem: a buffer for result DIE
*
* Find a variable DIE called @name at @addr in @sp_die.
*/
Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
Dwarf_Addr addr, Dwarf_Die *die_mem)
{
struct __find_variable_param fvp = { .name = name, .addr = addr};
return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
die_mem);
}
static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
{
const char *name = data;
if (dwarf_tag(die_mem) == DW_TAG_member) {
if (die_compare_name(die_mem, name))
return DIE_FIND_CB_END;
else if (!dwarf_diename(die_mem)) { /* Unnamed structure */
Dwarf_Die type_die, tmp_die;
if (die_get_type(die_mem, &type_die) &&
die_find_member(&type_die, name, &tmp_die))
return DIE_FIND_CB_END;
}
}
return DIE_FIND_CB_SIBLING;
}
/**
* die_find_member - Find a given name member in a data structure
* @st_die: a data structure type DIE
* @name: member name
* @die_mem: a buffer for result DIE
*
* Find a member DIE called @name in @st_die.
*/
Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
Dwarf_Die *die_mem)
{
return die_find_child(st_die, __die_find_member_cb, (void *)name,
die_mem);
}
/**
* die_get_typename - Get the name of given variable DIE
* @vr_die: a variable DIE
* @buf: a buffer for result type name
* @len: a max-length of @buf
*
* Get the name of @vr_die and stores it to @buf. Return the actual length
* of type name if succeeded. Return -E2BIG if @len is not enough long, and
* Return -ENOENT if failed to find type name.
* Note that the result will stores typedef name if possible, and stores
* "*(function_type)" if the type is a function pointer.
*/
int die_get_typename(Dwarf_Die *vr_die, char *buf, int len)
{
Dwarf_Die type;
int tag, ret, ret2;
const char *tmp = "";
if (__die_get_real_type(vr_die, &type) == NULL)
return -ENOENT;
tag = dwarf_tag(&type);
if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
tmp = "*";
else if (tag == DW_TAG_subroutine_type) {
/* Function pointer */
ret = snprintf(buf, len, "(function_type)");
return (ret >= len) ? -E2BIG : ret;
} else {
if (!dwarf_diename(&type))
return -ENOENT;
if (tag == DW_TAG_union_type)
tmp = "union ";
else if (tag == DW_TAG_structure_type)
tmp = "struct ";
else if (tag == DW_TAG_enumeration_type)
tmp = "enum ";
/* Write a base name */
ret = snprintf(buf, len, "%s%s", tmp, dwarf_diename(&type));
return (ret >= len) ? -E2BIG : ret;
}
ret = die_get_typename(&type, buf, len);
if (ret > 0) {
ret2 = snprintf(buf + ret, len - ret, "%s", tmp);
ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
}
return ret;
}
/**
* die_get_varname - Get the name and type of given variable DIE
* @vr_die: a variable DIE
* @buf: a buffer for type and variable name
* @len: the max-length of @buf
*
* Get the name and type of @vr_die and stores it in @buf as "type\tname".
*/
int die_get_varname(Dwarf_Die *vr_die, char *buf, int len)
{
int ret, ret2;
ret = die_get_typename(vr_die, buf, len);
if (ret < 0) {
pr_debug("Failed to get type, make it unknown.\n");
ret = snprintf(buf, len, "(unknown_type)");
}
if (ret > 0) {
ret2 = snprintf(buf + ret, len - ret, "\t%s",
dwarf_diename(vr_die));
ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
}
return ret;
}
/* 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) != 0)
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 pc 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 = convert_probe_point(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 kprobe_trace_events specified by perf_probe_event from debuginfo */
int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
struct kprobe_trace_event **tevs, int max_tevs)
{
struct probe_finder pf = {.pev = pev, .max_tevs = max_tevs};
struct perf_probe_point *pp = &pev->point;
Dwarf_Off off, noff;
size_t cuhl;
Dwarf_Die *diep;
Dwarf *dbg;
int ret = 0;
pf.tevs = zalloc(sizeof(struct kprobe_trace_event) * max_tevs);
if (pf.tevs == NULL)
return -ENOMEM;
*tevs = pf.tevs;
pf.ntevs = 0;
dbg = dwarf_begin(fd, DWARF_C_READ);
if (!dbg) {
pr_warning("No dwarf info found in the vmlinux - "
"please rebuild with CONFIG_DEBUG_INFO=y.\n");
free(pf.tevs);
*tevs = NULL;
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) &&
ret >= 0) {
/* 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);
}
}
off = noff;
}
line_list__free(&pf.lcache);
dwarf_end(dbg);
return (ret < 0) ? ret : pf.ntevs;
}
/* Reverse search */
int find_perf_probe_point(int fd, unsigned long addr,
struct perf_probe_point *ppt)
{
Dwarf_Die cudie, spdie, indie;
Dwarf *dbg;
Dwarf_Line *line;
Dwarf_Addr laddr, eaddr;
const char *tmp;
int lineno, ret = 0;
bool found = false;
dbg = dwarf_begin(fd, DWARF_C_READ);
if (!dbg)
return -EBADF;
/* Find cu die */
if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr, &cudie)) {
ret = -EINVAL;
goto end;
}
/* Find a corresponding line */
line = dwarf_getsrc_die(&cudie, (Dwarf_Addr)addr);
if (line) {
if (dwarf_lineaddr(line, &laddr) == 0 &&
(Dwarf_Addr)addr == laddr &&
dwarf_lineno(line, &lineno) == 0) {
tmp = dwarf_linesrc(line, NULL, NULL);
if (tmp) {
ppt->line = lineno;
ppt->file = strdup(tmp);
if (ppt->file == NULL) {
ret = -ENOMEM;
goto end;
}
found = true;
}
}
}
/* Find a corresponding function */
if (die_find_real_subprogram(&cudie, (Dwarf_Addr)addr, &spdie)) {
tmp = dwarf_diename(&spdie);
if (!tmp || dwarf_entrypc(&spdie, &eaddr) != 0)
goto end;
if (ppt->line) {
if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr,
&indie)) {
/* addr in an inline function */
tmp = dwarf_diename(&indie);
if (!tmp)
goto end;
ret = dwarf_decl_line(&indie, &lineno);
} else {
if (eaddr == addr) { /* Function entry */
lineno = ppt->line;
ret = 0;
} else
ret = dwarf_decl_line(&spdie, &lineno);
}
if (ret == 0) {
/* Make a relative line number */
ppt->line -= lineno;
goto found;
}
}
/* We don't have a line number, let's use offset */
ppt->offset = addr - (unsigned long)eaddr;
found:
ppt->function = strdup(tmp);
if (ppt->function == NULL) {
ret = -ENOMEM;
goto end;
}
found = true;
}
end:
dwarf_end(dbg);
if (ret >= 0)
ret = found ? 1 : 0;
return ret;
}
/* Add a line and store the src path */
static int line_range_add_line(const char *src, unsigned int lineno,
struct line_range *lr)
{
/* Copy real path */
if (!lr->path) {
lr->path = strdup(src);
if (lr->path == NULL)
return -ENOMEM;
}
return line_list__add_line(&lr->line_list, lineno);
}
/* Search function declaration lines */
static int line_range_funcdecl_cb(Dwarf_Die *sp_die, void *data)
{
struct dwarf_callback_param *param = data;
struct line_finder *lf = param->data;
const char *src;
int lineno;
src = dwarf_decl_file(sp_die);
if (src && strtailcmp(src, lf->fname) != 0)
return DWARF_CB_OK;
if (dwarf_decl_line(sp_die, &lineno) != 0 ||
(lf->lno_s > lineno || lf->lno_e < lineno))
return DWARF_CB_OK;
param->retval = line_range_add_line(src, lineno, lf->lr);
if (param->retval < 0)
return DWARF_CB_ABORT;
return DWARF_CB_OK;
}
static int find_line_range_func_decl_lines(struct line_finder *lf)
{
struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
dwarf_getfuncs(&lf->cu_die, line_range_funcdecl_cb, ¶m, 0);
return param.retval;
}
/* Find line range from its line number */
static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
{
Dwarf_Lines *lines;
Dwarf_Line *line;
size_t nlines, i;
Dwarf_Addr addr;
int lineno, ret = 0;
const char *src;
Dwarf_Die die_mem;
line_list__init(&lf->lr->line_list);
if (dwarf_getsrclines(&lf->cu_die, &lines, &nlines) != 0) {
pr_warning("No source lines found in this CU.\n");
return -ENOENT;
}
/* Search probable lines on lines list */
for (i = 0; i < nlines; i++) {
line = dwarf_onesrcline(lines, i);
if (dwarf_lineno(line, &lineno) != 0 ||
(lf->lno_s > lineno || lf->lno_e < lineno))
continue;
if (sp_die) {
/* Address filtering 1: does sp_die include addr? */
if (dwarf_lineaddr(line, &addr) != 0 ||
!dwarf_haspc(sp_die, addr))
continue;
/* Address filtering 2: No child include addr? */
if (die_find_inlinefunc(sp_die, addr, &die_mem))
continue;
}
/* TODO: Get fileno from line, but how? */
src = dwarf_linesrc(line, NULL, NULL);
if (strtailcmp(src, lf->fname) != 0)
continue;
ret = line_range_add_line(src, lineno, lf->lr);
if (ret < 0)
return ret;
}
/*
* Dwarf lines doesn't include function declarations. We have to
* check functions list or given function.
*/
if (sp_die) {
src = dwarf_decl_file(sp_die);
if (src && dwarf_decl_line(sp_die, &lineno) == 0 &&
(lf->lno_s <= lineno && lf->lno_e >= lineno))
ret = line_range_add_line(src, lineno, lf->lr);
} else
ret = find_line_range_func_decl_lines(lf);
/* Update status */
if (ret >= 0)
if (!list_empty(&lf->lr->line_list))
ret = lf->found = 1;
else
ret = 0; /* Lines are not found */
else {
free(lf->lr->path);
lf->lr->path = NULL;
}
return ret;
}
static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
{
struct dwarf_callback_param *param = data;
param->retval = find_line_range_by_line(in_die, param->data);
return DWARF_CB_ABORT; /* No need to find other instances */
}
/* Search function from function name */
static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
{
struct dwarf_callback_param *param = data;
struct line_finder *lf = param->data;
struct line_range *lr = lf->lr;
if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
die_compare_name(sp_die, lr->function) == 0) {
lf->fname = dwarf_decl_file(sp_die);
dwarf_decl_line(sp_die, &lr->offset);
pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
lf->lno_s = lr->offset + lr->start;
if (lf->lno_s < 0) /* Overflow */
lf->lno_s = INT_MAX;
lf->lno_e = lr->offset + lr->end;
if (lf->lno_e < 0) /* Overflow */
lf->lno_e = INT_MAX;
pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
lr->start = lf->lno_s;
lr->end = lf->lno_e;
if (dwarf_func_inline(sp_die)) {
struct dwarf_callback_param _param;
_param.data = (void *)lf;
_param.retval = 0;
dwarf_func_inline_instances(sp_die,
line_range_inline_cb,
&_param);
param->retval = _param.retval;
} else
param->retval = find_line_range_by_line(sp_die, lf);
return DWARF_CB_ABORT;
}
return DWARF_CB_OK;
}
static int find_line_range_by_func(struct line_finder *lf)
{
struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
dwarf_getfuncs(&lf->cu_die, line_range_search_cb, ¶m, 0);
return param.retval;
}
int find_line_range(int fd, struct line_range *lr)
{
struct line_finder lf = {.lr = lr, .found = 0};
int ret = 0;
Dwarf_Off off = 0, noff;
size_t cuhl;
Dwarf_Die *diep;
Dwarf *dbg;
dbg = dwarf_begin(fd, DWARF_C_READ);
if (!dbg) {
pr_warning("No dwarf info found in the vmlinux - "
"please rebuild with CONFIG_DEBUG_INFO=y.\n");
return -EBADF;
}
/* Loop on CUs (Compilation Unit) */
while (!lf.found && ret >= 0) {
if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
break;
/* Get the DIE(Debugging Information Entry) of this CU */
diep = dwarf_offdie(dbg, off + cuhl, &lf.cu_die);
if (!diep)
continue;
/* Check if target file is included. */
if (lr->file)
lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
else
lf.fname = 0;
if (!lr->file || lf.fname) {
if (lr->function)
ret = find_line_range_by_func(&lf);
else {
lf.lno_s = lr->start;
lf.lno_e = lr->end;
ret = find_line_range_by_line(NULL, &lf);
}
}
off = noff;
}
pr_debug("path: %lx\n", (unsigned long)lr->path);
dwarf_end(dbg);
return (ret < 0) ? ret : lf.found;
}
/* Find probe points from lazy pattern */
static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
{
Dwarf_Lines *lines;
Dwarf_Line *line;
size_t nlines, i;
Dwarf_Addr addr;
Dwarf_Die die_mem;
int lineno;
int ret = 0;
if (list_empty(&pf->lcache)) {
/* Matching lazy line pattern */
ret = find_lazy_match_lines(&pf->lcache, pf->fname,
pf->pev->point.lazy_line);
if (ret == 0) {
pr_debug("No matched lines found in %s.\n", pf->fname);
return 0;
} else if (ret < 0)
return ret;
}
if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
pr_warning("No source lines found in this CU.\n");
return -ENOENT;
}
for (i = 0; i < nlines && ret >= 0; i++) {
line = dwarf_onesrcline(lines, i);
if (dwarf_lineno(line, &lineno) != 0 ||
!line_list__has_line(&pf->lcache, lineno))
continue;
/* TODO: Get fileno from line, but how? */
if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
continue;
if (dwarf_lineaddr(line, &addr) != 0) {
pr_debug("Failed to get the address of line %d.\n",
lineno);
continue;
}
if (sp_die) {
/* Address filtering 1: does sp_die include addr? */
if (!dwarf_haspc(sp_die, addr))
continue;
/* Address filtering 2: No child include addr? */
if (die_find_inlinefunc(sp_die, addr, &die_mem))
continue;
}
pr_debug("Probe line found: line[%d]:%d addr:0x%llx\n",
(int)i, lineno, (unsigned long long)addr);
pf->addr = addr;
ret = convert_probe_point(sp_die, pf);
/* Continuing, because target line might be inlined. */
}
/* TODO: deallocate lines, but how? */
return ret;
}
/* Walk on lines of blocks included in given DIE */
static int __die_walk_funclines(Dwarf_Die *sp_die,
line_walk_handler_t handler, void *data)
{
struct __line_walk_param lw = {
.handler = handler,
.data = data,
.retval = 0,
};
Dwarf_Die die_mem;
Dwarf_Addr addr;
int lineno;
/* Handle function declaration line */
lw.fname = dwarf_decl_file(sp_die);
if (lw.fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
dwarf_entrypc(sp_die, &addr) == 0) {
lw.retval = handler(lw.fname, lineno, addr, data);
if (lw.retval != 0)
goto done;
}
die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
done:
return lw.retval;
}
static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
{
struct __line_walk_param *lw = data;
lw->retval = __die_walk_funclines(sp_die, lw->handler, lw->data);
if (lw->retval != 0)
return DWARF_CB_ABORT;
return DWARF_CB_OK;
}
/*
* Walk on lines inside given PDIE. If the PDIE is subprogram, walk only on
* the lines inside the subprogram, otherwise PDIE must be a CU DIE.
*/
static int die_walk_lines(Dwarf_Die *pdie, line_walk_handler_t handler,
void *data)
{
Dwarf_Lines *lines;
Dwarf_Line *line;
Dwarf_Addr addr;
const char *fname;
int lineno, ret = 0;
Dwarf_Die die_mem, *cu_die;
size_t nlines, i;
/* Get the CU die */
if (dwarf_tag(pdie) == DW_TAG_subprogram)
cu_die = dwarf_diecu(pdie, &die_mem, NULL, NULL);
else
cu_die = pdie;
if (!cu_die) {
pr_debug2("Failed to get CU from subprogram\n");
return -EINVAL;
}
/* Get lines list in the CU */
if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
pr_debug2("Failed to get source lines on this CU.\n");
return -ENOENT;
}
pr_debug2("Get %zd lines from this CU\n", nlines);
/* Walk on the lines on lines list */
for (i = 0; i < nlines; i++) {
line = dwarf_onesrcline(lines, i);
if (line == NULL ||
dwarf_lineno(line, &lineno) != 0 ||
dwarf_lineaddr(line, &addr) != 0) {
pr_debug2("Failed to get line info. "
"Possible error in debuginfo.\n");
continue;
}
/* Filter lines based on address */
if (pdie != cu_die)
/*
* Address filtering
* The line is included in given function, and
* no inline block includes it.
*/
if (!dwarf_haspc(pdie, addr) ||
die_find_inlinefunc(pdie, addr, &die_mem))
continue;
/* Get source line */
fname = dwarf_linesrc(line, NULL, NULL);
ret = handler(fname, lineno, addr, data);
if (ret != 0)
return ret;
}
/*
* Dwarf lines doesn't include function declarations and inlined
* subroutines. We have to check functions list or given function.
*/
if (pdie != cu_die)
ret = __die_walk_funclines(pdie, handler, data);
else {
struct __line_walk_param param = {
.handler = handler,
.data = data,
.retval = 0,
};
dwarf_getfuncs(cu_die, __die_walk_culines_cb, ¶m, 0);
ret = param.retval;
}
return ret;
}
struct __find_variable_param {
const char *name;
Dwarf_Addr addr;
};
static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
{
struct __find_variable_param *fvp = data;
int tag;
tag = dwarf_tag(die_mem);
if ((tag == DW_TAG_formal_parameter ||
tag == DW_TAG_variable) &&
die_compare_name(die_mem, fvp->name))
return DIE_FIND_CB_FOUND;
if (dwarf_haspc(die_mem, fvp->addr))
return DIE_FIND_CB_CONTINUE;
else
return DIE_FIND_CB_SIBLING;
}
/* Find a variable called 'name' at given address */
static Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
Dwarf_Addr addr, Dwarf_Die *die_mem)
{
struct __find_variable_param fvp = { .name = name, .addr = addr};
return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
die_mem);
}
static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
{
const char *name = data;
if ((dwarf_tag(die_mem) == DW_TAG_member) &&
die_compare_name(die_mem, name))
return DIE_FIND_CB_FOUND;
return DIE_FIND_CB_SIBLING;
}
/* Find a member called 'name' */
static Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
Dwarf_Die *die_mem)
{
return die_find_child(st_die, __die_find_member_cb, (void *)name,
die_mem);
}
/* Get the name of given variable DIE */
static int die_get_typename(Dwarf_Die *vr_die, char *buf, int len)
{
Dwarf_Die type;
int tag, ret, ret2;
const char *tmp = "";
if (__die_get_real_type(vr_die, &type) == NULL)
return -ENOENT;
tag = dwarf_tag(&type);
if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
tmp = "*";
else if (tag == DW_TAG_subroutine_type) {
/* Function pointer */
ret = snprintf(buf, len, "(function_type)");
return (ret >= len) ? -E2BIG : ret;
} else {
if (!dwarf_diename(&type))
return -ENOENT;
if (tag == DW_TAG_union_type)
tmp = "union ";
else if (tag == DW_TAG_structure_type)
tmp = "struct ";
/* Write a base name */
ret = snprintf(buf, len, "%s%s", tmp, dwarf_diename(&type));
return (ret >= len) ? -E2BIG : ret;
}
ret = die_get_typename(&type, buf, len);
if (ret > 0) {
ret2 = snprintf(buf + ret, len - ret, "%s", tmp);
ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
}
return ret;
}
/* 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;
}