selftests/bpf: Clean up sys_nanosleep uses

This patch cleans up a few things:

* dynptr_fail.c:
There is no sys_nanosleep tracepoint. dynptr_fail only tests
that the prog load fails, so just SEC("?raw_tp") suffices here.

* test_bpf_cookie:
There is no sys_nanosleep kprobe. The prog is loaded in
userspace through bpf_program__attach_kprobe_opts passing in
SYS_NANOSLEEP_KPROBE_NAME, so just SEC("k{ret}probe") suffices here.

* test_helper_restricted:
There is no sys_nanosleep kprobe. test_helper_restricted only tests
that the prog load fails, so just SEC("?kprobe")( suffices here.

There are no functional changes.

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220805171405.2272103-1-joannelkoong@gmail.com

selftests/bpf: Use non-autoloaded programs in few tests

Take advantage of new libbpf feature for declarative non-autoloaded BPF
program SEC() definitions in few test that test single program at a time
out of many available programs within the single BPF object.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220419002452.632125-2-andrii@kernel.org

selftests/bpf: Add tests for restricted helpers

This patch adds tests that bpf_ktime_get_coarse_ns(), bpf_timer_* and
bpf_spin_lock()/bpf_spin_unlock() helpers are forbidden in tracing progs
as their use there may result in various locking issues.

Signed-off-by: Dmitrii Banshchikov <me@ubique.spb.ru>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211113142227.566439-3-me@ubique.spb.ru