/* Call probe_finder callback with real subprogram DIE */
static int call_probe_finder(Dwarf_Die *sp_die, struct probe_finder *pf)
{
Dwarf_Die die_mem;
Dwarf_Attribute fb_attr;
size_t nops;
int ret;
/* If no real subprogram, find a real one */
if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
sp_die = die_find_real_subprogram(&pf->cu_die,
pf->addr, &die_mem);
if (!sp_die) {
pr_warning("Failed to find probe point in any "
"functions.\n");
return -ENOENT;
}
}
/* Get the frame base attribute/ops */
dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
if (ret <= 0 || nops == 0) {
pf->fb_ops = NULL;
#if _ELFUTILS_PREREQ(0, 142)
} else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
pf->cfi != NULL) {
Dwarf_Frame *frame;
if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
pr_warning("Failed to get call frame on 0x%jx\n",
(uintmax_t)pf->addr);
return -ENOENT;
}
#endif
}
/* Call finder's callback handler */
ret = pf->callback(sp_die, pf);
/* *pf->fb_ops will be cached in libdw. Don't free it. */
pf->fb_ops = NULL;
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;
}
/* Show a probe point to output buffer */
static int convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
{
struct kprobe_trace_event *tev;
Dwarf_Addr eaddr;
Dwarf_Die die_mem;
const char *name;
int ret, i;
Dwarf_Attribute fb_attr;
size_t nops;
if (pf->ntevs == pf->max_tevs) {
pr_warning("Too many( > %d) probe point found.\n",
pf->max_tevs);
return -ERANGE;
}
tev = &pf->tevs[pf->ntevs++];
/* If no real subprogram, find a real one */
if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
sp_die = die_find_real_subprogram(&pf->cu_die,
pf->addr, &die_mem);
if (!sp_die) {
pr_warning("Failed to find probe point in any "
"functions.\n");
return -ENOENT;
}
}
/* Copy the name of probe point */
name = dwarf_diename(sp_die);
if (name) {
if (dwarf_entrypc(sp_die, &eaddr) != 0) {
pr_warning("Failed to get entry pc of %s\n",
dwarf_diename(sp_die));
return -ENOENT;
}
tev->point.symbol = strdup(name);
if (tev->point.symbol == NULL)
return -ENOMEM;
tev->point.offset = (unsigned long)(pf->addr - eaddr);
} else
/* This function has no name. */
tev->point.offset = (unsigned long)pf->addr;
pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
tev->point.offset);
/* Get the frame base attribute/ops */
dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
if (ret <= 0 || nops == 0) {
pf->fb_ops = NULL;
#if _ELFUTILS_PREREQ(0, 142)
} else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
pf->cfi != NULL) {
Dwarf_Frame *frame;
if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
pr_warning("Failed to get CFA on 0x%jx\n",
(uintmax_t)pf->addr);
return -ENOENT;
}
#endif
}
/* Find each argument */
tev->nargs = pf->pev->nargs;
tev->args = zalloc(sizeof(struct kprobe_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;
}
/* *pf->fb_ops will be cached in libdw. Don't free it. */
pf->fb_ops = NULL;
return 0;
}
/* Reverse search */
int find_perf_probe_point(unsigned long addr, struct perf_probe_point *ppt)
{
Dwarf_Die cudie, spdie, indie;
Dwarf *dbg = NULL;
Dwfl *dwfl = NULL;
Dwarf_Line *line;
Dwarf_Addr laddr, eaddr, bias = 0;
const char *tmp;
int lineno, ret = 0;
bool found = false;
/* Open the live linux kernel */
dbg = dwfl_init_live_kernel_dwarf(addr, &dwfl, &bias);
if (!dbg) {
pr_warning("No debug information found in the vmlinux - "
"please rebuild with CONFIG_DEBUG_INFO=y.\n");
ret = -EINVAL;
goto end;
}
/* Adjust address with bias */
addr += bias;
/* Find cu die */
if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr - bias, &cudie)) {
pr_warning("Failed to find debug information for address %lx\n",
addr);
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:
if (dwfl)
dwfl_end(dwfl);
if (ret >= 0)
ret = found ? 1 : 0;
return ret;
}
