1 files changed, 52 insertions, 0 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index e402459752e7..f6664bb08b26 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -55,6 +55,9 @@
 #include <signal.h>
 #include <sys/mman.h>
 #include <sys/wait.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include <linux/err.h>
 #include <linux/string.h>
 #include <linux/time64.h>
@@ -699,6 +702,37 @@ static int record__auxtrace_init(struct record *rec __maybe_unused)
 
 #endif
 
+static bool record__kcore_readable(struct machine *machine)
+{
+	char kcore[PATH_MAX];
+	int fd;
+
+	scnprintf(kcore, sizeof(kcore), "%s/proc/kcore", machine->root_dir);
+
+	fd = open(kcore, O_RDONLY);
+	if (fd < 0)
+		return false;
+
+	close(fd);
+
+	return true;
+}
+
+static int record__kcore_copy(struct machine *machine, struct perf_data *data)
+{
+	char from_dir[PATH_MAX];
+	char kcore_dir[PATH_MAX];
+	int ret;
+
+	snprintf(from_dir, sizeof(from_dir), "%s/proc", machine->root_dir);
+
+	ret = perf_data__make_kcore_dir(data, kcore_dir, sizeof(kcore_dir));
+	if (ret)
+		return ret;
+
+	return kcore_copy(from_dir, kcore_dir);
+}
+
 static int record__mmap_evlist(struct record *rec,
 			       struct evlist *evlist)
 {
@@ -1383,6 +1417,12 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 	session->header.env.comp_type  = PERF_COMP_ZSTD;
 	session->header.env.comp_level = rec->opts.comp_level;
 
+	if (rec->opts.kcore &&
+	    !record__kcore_readable(&session->machines.host)) {
+		pr_err("ERROR: kcore is not readable.\n");
+		return -1;
+	}
+
 	record__init_features(rec);
 
 	if (rec->opts.use_clockid && rec->opts.clockid_res_ns)
@@ -1414,6 +1454,14 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 	}
 	session->header.env.comp_mmap_len = session->evlist->core.mmap_len;
 
+	if (rec->opts.kcore) {
+		err = record__kcore_copy(&session->machines.host, data);
+		if (err) {
+			pr_err("ERROR: Failed to copy kcore\n");
+			goto out_child;
+		}
+	}
+
 	err = bpf__apply_obj_config();
 	if (err) {
 		char errbuf[BUFSIZ];
@@ -2184,6 +2232,7 @@ static struct option __record_options[] = {
 		     parse_cgroups),
 	OPT_UINTEGER('D', "delay", &record.opts.initial_delay,
 		  "ms to wait before starting measurement after program start"),
+	OPT_BOOLEAN(0, "kcore", &record.opts.kcore, "copy /proc/kcore"),
 	OPT_STRING('u', "uid", &record.opts.target.uid_str, "user",
 		   "user to profile"),
 
@@ -2322,6 +2371,9 @@ int cmd_record(int argc, const char **argv)
 
 	}
 
+	if (rec->opts.kcore)
+		rec->data.is_dir = true;
+
 	if (rec->opts.comp_level != 0) {
 		pr_debug("Compression enabled, disabling build id collection at the end of the session.\n");
 		rec->no_buildid = true;