Kurt Kanzenbach 64e15820b9 selftests/bpf: Add BPF-helper test for CLOCK_TAI access
Add BPF-helper test case for CLOCK_TAI access. The added test verifies that:

 * Timestamps are generated
 * Timestamps are moving forward
 * Timestamps are reasonable

Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Link: https://lore.kernel.org/r/20220809060803.5773-3-kurt@linutronix.de
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-08-09 09:47:13 -07:00

25 lines
480 B
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2022 Linutronix GmbH */
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
char _license[] SEC("license") = "GPL";
SEC("tc")
int time_tai(struct __sk_buff *skb)
{
__u64 ts1, ts2;
/* Get TAI timestamps */
ts1 = bpf_ktime_get_tai_ns();
ts2 = bpf_ktime_get_tai_ns();
/* Save TAI timestamps (Note: skb->hwtstamp is read-only) */
skb->tstamp = ts1;
skb->cb[0] = ts2 & 0xffffffff;
skb->cb[1] = ts2 >> 32;
return 0;
}