v4.19.13 snapshot.
diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c
new file mode 100644
index 0000000..ca0fff6
--- /dev/null
+++ b/tools/perf/util/cloexec.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <errno.h>
+#include <sched.h>
+#include "util.h"
+#include "../perf.h"
+#include "cloexec.h"
+#include "asm/bug.h"
+#include "debug.h"
+#include <unistd.h>
+#include <asm/unistd.h>
+#include <sys/syscall.h>
+
+static unsigned long flag = PERF_FLAG_FD_CLOEXEC;
+
+int __weak sched_getcpu(void)
+{
+#ifdef __NR_getcpu
+ unsigned cpu;
+ int err = syscall(__NR_getcpu, &cpu, NULL, NULL);
+ if (!err)
+ return cpu;
+#else
+ errno = ENOSYS;
+#endif
+ return -1;
+}
+
+static int perf_flag_probe(void)
+{
+ /* use 'safest' configuration as used in perf_evsel__fallback() */
+ struct perf_event_attr attr = {
+ .type = PERF_TYPE_SOFTWARE,
+ .config = PERF_COUNT_SW_CPU_CLOCK,
+ .exclude_kernel = 1,
+ };
+ int fd;
+ int err;
+ int cpu;
+ pid_t pid = -1;
+ char sbuf[STRERR_BUFSIZE];
+
+ cpu = sched_getcpu();
+ if (cpu < 0)
+ cpu = 0;
+
+ /*
+ * Using -1 for the pid is a workaround to avoid gratuitous jump label
+ * changes.
+ */
+ while (1) {
+ /* check cloexec flag */
+ fd = sys_perf_event_open(&attr, pid, cpu, -1,
+ PERF_FLAG_FD_CLOEXEC);
+ if (fd < 0 && pid == -1 && errno == EACCES) {
+ pid = 0;
+ continue;
+ }
+ break;
+ }
+ err = errno;
+
+ if (fd >= 0) {
+ close(fd);
+ return 1;
+ }
+
+ WARN_ONCE(err != EINVAL && err != EBUSY,
+ "perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n",
+ err, str_error_r(err, sbuf, sizeof(sbuf)));
+
+ /* not supported, confirm error related to PERF_FLAG_FD_CLOEXEC */
+ while (1) {
+ fd = sys_perf_event_open(&attr, pid, cpu, -1, 0);
+ if (fd < 0 && pid == -1 && errno == EACCES) {
+ pid = 0;
+ continue;
+ }
+ break;
+ }
+ err = errno;
+
+ if (fd >= 0)
+ close(fd);
+
+ if (WARN_ONCE(fd < 0 && err != EBUSY,
+ "perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n",
+ err, str_error_r(err, sbuf, sizeof(sbuf))))
+ return -1;
+
+ return 0;
+}
+
+unsigned long perf_event_open_cloexec_flag(void)
+{
+ static bool probed;
+
+ if (!probed) {
+ if (perf_flag_probe() <= 0)
+ flag = 0;
+ probed = true;
+ }
+
+ return flag;
+}