bpf: add bpf_modify_return_test_tp() kfunc triggering tracepoint

Add a simple bpf_modify_return_test_tp() kfunc, available to all program
types, that is useful for various testing and benchmarking scenarios, as
it allows to trigger most tracing BPF program types from BPF side,
allowing to do complex testing and benchmarking scenarios.

It is also attachable to for fmod_ret programs, making it a good and
simple way to trigger fmod_ret program under test/benchmark.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240326162151.3981687-6-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/include/trace/events/bpf_test_run.h b/include/trace/events/bpf_test_run.h
index 265447e3f71abeea68de239f722c6428fe5b8289..0c924d39b7cbaf326e81c52174f93d4dc97b0f58 100644 (file)
--- a/include/trace/events/bpf_test_run.h
+++ b/include/trace/events/bpf_test_run.h
@@ -7,6 +7,23 @@
 
 #include <linux/tracepoint.h>
 
+TRACE_EVENT(bpf_trigger_tp,
+
+       TP_PROTO(int nonce),
+
+       TP_ARGS(nonce),
+
+       TP_STRUCT__entry(
+               __field(int, nonce)
+       ),
+
+       TP_fast_assign(
+               __entry->nonce = nonce;
+       ),
+
+       TP_printk("nonce %d", __entry->nonce)
+);
+
 DECLARE_EVENT_CLASS(bpf_test_finish,
 
        TP_PROTO(int *err),

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index f860adab3eb960106a3184c59d3a3a045e6c22ae..d9e7aca8ae9e86d22ce4e7b26cf01a5f02bc6f95 100644 (file)
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -2625,6 +2625,7 @@ BTF_ID_FLAGS(func, bpf_dynptr_is_null)
 BTF_ID_FLAGS(func, bpf_dynptr_is_rdonly)
 BTF_ID_FLAGS(func, bpf_dynptr_size)
 BTF_ID_FLAGS(func, bpf_dynptr_clone)
+BTF_ID_FLAGS(func, bpf_modify_return_test_tp)
 BTF_KFUNCS_END(common_btf_ids)
 
 static const struct btf_kfunc_id_set common_kfunc_set = {

diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 61efeadaff8db0529a62d074f441e2a7c35eaa9e..f6aad4ed2ab2f6b09ad2f6442cde26b39949871a 100644 (file)
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -575,6 +575,13 @@ __bpf_kfunc int bpf_modify_return_test2(int a, int *b, short c, int d,
        return a + *b + c + d + (long)e + f + g;
 }
 
+__bpf_kfunc int bpf_modify_return_test_tp(int nonce)
+{
+       trace_bpf_trigger_tp(nonce);
+
+       return nonce;
+}
+
 int noinline bpf_fentry_shadow_test(int a)
 {
        return a + 1;
@@ -622,6 +629,7 @@ __bpf_kfunc_end_defs();
 BTF_KFUNCS_START(bpf_test_modify_return_ids)
 BTF_ID_FLAGS(func, bpf_modify_return_test)
 BTF_ID_FLAGS(func, bpf_modify_return_test2)
+BTF_ID_FLAGS(func, bpf_modify_return_test_tp)
 BTF_ID_FLAGS(func, bpf_fentry_test1, KF_SLEEPABLE)
 BTF_KFUNCS_END(bpf_test_modify_return_ids)