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309 lines
8.3 KiB
309 lines
8.3 KiB
/*
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* builtin-probe.c
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*
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* Builtin probe command: Set up probe events by C expression
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*
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* Written by Masami Hiramatsu <mhiramat@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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*/
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#define _GNU_SOURCE
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#include <sys/utsname.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#undef _GNU_SOURCE
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#include "perf.h"
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#include "builtin.h"
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#include "util/util.h"
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#include "util/strlist.h"
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#include "util/event.h"
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#include "util/debug.h"
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#include "util/debugfs.h"
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#include "util/symbol.h"
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#include "util/thread.h"
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#include "util/session.h"
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#include "util/parse-options.h"
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#include "util/parse-events.h" /* For debugfs_path */
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#include "util/probe-finder.h"
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#include "util/probe-event.h"
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#define MAX_PATH_LEN 256
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#define MAX_PROBES 128
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/* Session management structure */
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static struct {
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bool need_dwarf;
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bool list_events;
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bool force_add;
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int nr_probe;
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struct probe_point probes[MAX_PROBES];
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struct strlist *dellist;
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struct perf_session *psession;
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struct map *kmap;
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} session;
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/* Parse an event definition. Note that any error must die. */
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static void parse_probe_event(const char *str)
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{
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struct probe_point *pp = &session.probes[session.nr_probe];
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pr_debug("probe-definition(%d): %s\n", session.nr_probe, str);
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if (++session.nr_probe == MAX_PROBES)
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die("Too many probes (> %d) are specified.", MAX_PROBES);
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/* Parse perf-probe event into probe_point */
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parse_perf_probe_event(str, pp, &session.need_dwarf);
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pr_debug("%d arguments\n", pp->nr_args);
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}
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static void parse_probe_event_argv(int argc, const char **argv)
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{
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int i, len;
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char *buf;
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/* Bind up rest arguments */
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len = 0;
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for (i = 0; i < argc; i++)
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len += strlen(argv[i]) + 1;
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buf = zalloc(len + 1);
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if (!buf)
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die("Failed to allocate memory for binding arguments.");
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len = 0;
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for (i = 0; i < argc; i++)
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len += sprintf(&buf[len], "%s ", argv[i]);
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parse_probe_event(buf);
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free(buf);
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}
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static int opt_add_probe_event(const struct option *opt __used,
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const char *str, int unset __used)
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{
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if (str)
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parse_probe_event(str);
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return 0;
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}
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static int opt_del_probe_event(const struct option *opt __used,
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const char *str, int unset __used)
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{
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if (str) {
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if (!session.dellist)
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session.dellist = strlist__new(true, NULL);
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strlist__add(session.dellist, str);
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}
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return 0;
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}
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/* Currently just checking function name from symbol map */
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static void evaluate_probe_point(struct probe_point *pp)
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{
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struct symbol *sym;
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sym = map__find_symbol_by_name(session.kmap, pp->function,
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session.psession, NULL);
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if (!sym)
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die("Kernel symbol \'%s\' not found - probe not added.",
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pp->function);
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}
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#ifndef NO_LIBDWARF
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static int open_vmlinux(void)
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{
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if (map__load(session.kmap, session.psession, NULL) < 0) {
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pr_debug("Failed to load kernel map.\n");
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return -EINVAL;
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}
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pr_debug("Try to open %s\n", session.kmap->dso->long_name);
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return open(session.kmap->dso->long_name, O_RDONLY);
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}
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#endif
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static const char * const probe_usage[] = {
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"perf probe [<options>] 'PROBEDEF' ['PROBEDEF' ...]",
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"perf probe [<options>] --add 'PROBEDEF' [--add 'PROBEDEF' ...]",
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"perf probe [<options>] --del '[GROUP:]EVENT' ...",
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"perf probe --list",
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NULL
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};
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static const struct option options[] = {
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OPT_BOOLEAN('v', "verbose", &verbose,
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"be more verbose (show parsed arguments, etc)"),
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#ifndef NO_LIBDWARF
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OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
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"file", "vmlinux pathname"),
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#endif
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OPT_BOOLEAN('l', "list", &session.list_events,
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"list up current probe events"),
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OPT_CALLBACK('d', "del", NULL, "[GROUP:]EVENT", "delete a probe event.",
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opt_del_probe_event),
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OPT_CALLBACK('a', "add", NULL,
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#ifdef NO_LIBDWARF
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"[EVENT=]FUNC[+OFFS|%return] [ARG ...]",
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#else
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"[EVENT=]FUNC[+OFFS|%return|:RLN][@SRC]|SRC:ALN [ARG ...]",
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#endif
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"probe point definition, where\n"
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"\t\tGROUP:\tGroup name (optional)\n"
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"\t\tEVENT:\tEvent name\n"
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"\t\tFUNC:\tFunction name\n"
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"\t\tOFFS:\tOffset from function entry (in byte)\n"
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"\t\t%return:\tPut the probe at function return\n"
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#ifdef NO_LIBDWARF
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"\t\tARG:\tProbe argument (only \n"
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#else
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"\t\tSRC:\tSource code path\n"
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"\t\tRLN:\tRelative line number from function entry.\n"
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"\t\tALN:\tAbsolute line number in file.\n"
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"\t\tARG:\tProbe argument (local variable name or\n"
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#endif
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"\t\t\tkprobe-tracer argument format.)\n",
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opt_add_probe_event),
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OPT_BOOLEAN('f', "force", &session.force_add, "forcibly add events"
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" with existing name"),
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OPT_END()
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};
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int cmd_probe(int argc, const char **argv, const char *prefix __used)
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{
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int i, ret;
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#ifndef NO_LIBDWARF
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int fd;
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#endif
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struct probe_point *pp;
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argc = parse_options(argc, argv, options, probe_usage,
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PARSE_OPT_STOP_AT_NON_OPTION);
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if (argc > 0) {
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if (strcmp(argv[0], "-") == 0) {
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pr_warning(" Error: '-' is not supported.\n");
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usage_with_options(probe_usage, options);
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}
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parse_probe_event_argv(argc, argv);
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}
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if ((!session.nr_probe && !session.dellist && !session.list_events))
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usage_with_options(probe_usage, options);
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if (debugfs_valid_mountpoint(debugfs_path) < 0)
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die("Failed to find debugfs path.");
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if (session.list_events) {
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if (session.nr_probe != 0 || session.dellist) {
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pr_warning(" Error: Don't use --list with"
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" --add/--del.\n");
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usage_with_options(probe_usage, options);
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}
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show_perf_probe_events();
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return 0;
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}
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if (session.dellist) {
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del_trace_kprobe_events(session.dellist);
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strlist__delete(session.dellist);
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if (session.nr_probe == 0)
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return 0;
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}
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/* Initialize symbol maps for vmlinux */
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symbol_conf.sort_by_name = true;
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if (symbol_conf.vmlinux_name == NULL)
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symbol_conf.try_vmlinux_path = true;
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if (symbol__init() < 0)
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die("Failed to init symbol map.");
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session.psession = perf_session__new(NULL, O_WRONLY, false);
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if (session.psession == NULL)
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die("Failed to init perf_session.");
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session.kmap = map_groups__find_by_name(&session.psession->kmaps,
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MAP__FUNCTION,
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"[kernel.kallsyms]");
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if (!session.kmap)
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die("Could not find kernel map.\n");
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if (session.need_dwarf)
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#ifdef NO_LIBDWARF
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die("Debuginfo-analysis is not supported");
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#else /* !NO_LIBDWARF */
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pr_debug("Some probes require debuginfo.\n");
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fd = open_vmlinux();
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if (fd < 0) {
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if (session.need_dwarf)
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die("Could not open debuginfo file.");
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pr_debug("Could not open vmlinux/module file."
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" Try to use symbols.\n");
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goto end_dwarf;
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}
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/* Searching probe points */
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for (i = 0; i < session.nr_probe; i++) {
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pp = &session.probes[i];
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if (pp->found)
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continue;
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lseek(fd, SEEK_SET, 0);
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ret = find_probepoint(fd, pp);
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if (ret > 0)
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continue;
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if (ret == 0) { /* No error but failed to find probe point. */
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synthesize_perf_probe_point(pp);
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die("Probe point '%s' not found. - probe not added.",
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pp->probes[0]);
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}
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/* Error path */
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if (session.need_dwarf) {
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if (ret == -ENOENT)
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pr_warning("No dwarf info found in the vmlinux - please rebuild with CONFIG_DEBUG_INFO=y.\n");
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die("Could not analyze debuginfo.");
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}
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pr_debug("An error occurred in debuginfo analysis."
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" Try to use symbols.\n");
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break;
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}
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close(fd);
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end_dwarf:
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#endif /* !NO_LIBDWARF */
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/* Synthesize probes without dwarf */
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for (i = 0; i < session.nr_probe; i++) {
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pp = &session.probes[i];
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if (pp->found) /* This probe is already found. */
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continue;
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evaluate_probe_point(pp);
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ret = synthesize_trace_kprobe_event(pp);
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if (ret == -E2BIG)
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die("probe point definition becomes too long.");
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else if (ret < 0)
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die("Failed to synthesize a probe point.");
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}
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/* Settng up probe points */
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add_trace_kprobe_events(session.probes, session.nr_probe,
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session.force_add);
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return 0;
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}
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