bpf/selftests: Add test for writable bare tracepoint

Add a writable bare tracepoint in bpf_testmod module, and
trigger its calling when reading /sys/kernel/bpf_testmod
with a specific buffer length. The reading will return
the value in writable context if the early return flag
is enabled in writable context.

Signed-off-by: Hou Tao <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

1 files changed, 14 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/test_module_attach.c b/tools/testing/selftests/bpf/progs/test_module_attach.c
index bd37ceec5587..b36857093f71 100644
--- a/tools/testing/selftests/bpf/progs/test_module_attach.c
+++ b/tools/testing/selftests/bpf/progs/test_module_attach.c
@@ -27,6 +27,20 @@ int BPF_PROG(handle_raw_tp_bare,
 	return 0;
 }
 
+int raw_tp_writable_bare_in_val = 0;
+int raw_tp_writable_bare_early_ret = 0;
+int raw_tp_writable_bare_out_val = 0;
+
+SEC("raw_tp.w/bpf_testmod_test_writable_bare")
+int BPF_PROG(handle_raw_tp_writable_bare,
+	     struct bpf_testmod_test_writable_ctx *writable)
+{
+	raw_tp_writable_bare_in_val = writable->val;
+	writable->early_ret = raw_tp_writable_bare_early_ret;
+	writable->val = raw_tp_writable_bare_out_val;
+	return 0;
+}
+
 __u32 tp_btf_read_sz = 0;
 
 SEC("tp_btf/bpf_testmod_test_read")