On 8/29/24 12:27 AM, Eduard Zingerman wrote:
On Tue, 2024-08-27 at 12:48 -0700, Martin KaFai Lau wrote:
From: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
This test adds a new struct_ops "bpf_testmod_st_ops" in bpf_testmod.
The ops of the bpf_testmod_st_ops is triggered by new kfunc calls
"bpf_kfunc_st_ops_test_*logue". These new kfunc calls are
primarily used by the SEC("syscall") program. The test triggering
sequence is like:
SEC("syscall")
syscall_prologue_subprog(struct st_ops_args *args)
bpf_kfunc_st_op_test_prologue(args)
st_ops->test_prologue(args)
.gen_prologue adds 1000 to args->a
.gen_epilogue adds 10000 to args->a
.gen_epilogue will also set the r0 to 2 * args->a.
The .gen_prologue and .gen_epilogue of the bpf_testmod_st_ops
will test the prog->aux->attach_func_name to decide if
it needs to generate codes.
The main programs of the pro_epilogue_subprog.c will call a subprog()
which does "args->a += 1".
The main programs of the pro_epilogue_kfunc.c will call a
new kfunc bpf_kfunc_st_ops_inc10 which does "args->a += 10".
This patch uses the test_loader infra to check the __xlated
instructions patched after gen_prologue and/or gen_epilogue.
The __xlated check is based on Eduard's example (Thanks!) in v1.
args->a is returned by the struct_ops prog (either the main prog
or the epilogue). Thus, the __retval of the SEC("syscall") prog
is checked. For example, when triggering the ops in the
'SEC("struct_ops/test_epilogue_subprog") int test_epilogue_subprog'
The expected args->a is +1 (subprog call) + 10000 (.gen_epilogue) = 10001.
The expected return value is 2 * 10001 (.gen_epilogue).
Suggested-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
Signed-off-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
---
Acked-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
[...]
diff --git a/tools/testing/selftests/bpf/progs/pro_epilogue_kfunc.c b/tools/testing/selftests/bpf/progs/pro_epilogue_kfunc.c
new file mode 100644
index 000000000000..7d1124cf4942
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/pro_epilogue_kfunc.c
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+
+#include <vmlinux.h>
+#include <bpf/bpf_tracing.h>
+#include "bpf_misc.h"
+#include "../bpf_testmod/bpf_testmod.h"
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
+
+char _license[] SEC("license") = "GPL";
+
+void __kfunc_btf_root(void)
+{
+ struct st_ops_args args = {};
+
+ bpf_kfunc_st_ops_inc10(&args);
Nit: 'bpf_kfunc_st_ops_inc10(0);' would also work.
sgtm. I think it will make it obvious that it won't be executed also.
+}
As a side note, I think that kfunc and subprog sets of tests could be
combined in order to have less code. Probably does not matter.
ok. I will drop the _subprog.c and only keep the _kfunc.c.
The _kfunc.c calls a subprog and a kfunc which should have already covered the
_subprog.c cases.
