libbpf: Support detecting writable tracepoint program

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I53R0H
CVE: NA
backport: openEuler-22.03-LTS

---------------------------

Identify writable tracepoint program by section prefix
raw_tracepoint.w/.

The correct way is back-porting from commit ccaf12d6
("libbpf: Support detecting and attaching of writable tracepoint program"),
but the refactoring of libbpf makes it hard, so using the same section
prefix as ccaf12d6 and post a home-made patch instead.
Signed-off-by: NHou Tao <houtao1@huawei.com>
Reviewed-by: NKuohai Xu <xukuohai@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NZhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: NKuohai Xu <xukuohai@huawei.com>
Reviewed-by: NKuohai Xu <xukuohai@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

tools/lib/bpf/libbpf.c

@@ -8320,6 +8320,7 @@ static const struct bpf_sec_def section_defs[] = {
 		.attach_fn = attach_tp),
 	SEC_DEF("raw_tracepoint/", RAW_TRACEPOINT,
 		.attach_fn = attach_raw_tp),
+	BPF_PROG_SEC("raw_tracepoint.w/", BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE),
 	SEC_DEF("raw_tp/", RAW_TRACEPOINT,
 		.attach_fn = attach_raw_tp),
 	SEC_DEF("tp_btf/", TRACING,