From c2a0257c1edf16c6acd2afac7572d7e9043b6577 Mon Sep 17 00:00:00 2001 From: Kui-Feng Lee Date: Mon, 11 Mar 2024 18:37:26 -0700 Subject: [PATCH] bpftool: Cast pointers for shadow types explicitly. According to a report, skeletons fail to assign shadow pointers when being compiled with C++ programs. Unlike C doing implicit casting for void pointers, C++ requires an explicit casting. To support C++, we do explicit casting for each shadow pointer. Also add struct_ops_module.skel.h to test_cpp to validate C++ compilation as part of BPF selftests. Signed-off-by: Kui-Feng Lee Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song Acked-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20240312013726.1780720-1-thinker.li@gmail.com --- tools/bpf/bpftool/gen.c | 3 ++- tools/testing/selftests/bpf/test_cpp.cpp | 5 +++++ 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c index 4fa4ade1ce7445..3ce277544c246d 100644 --- a/tools/bpf/bpftool/gen.c +++ b/tools/bpf/bpftool/gen.c @@ -1131,7 +1131,8 @@ static void gen_st_ops_shadow_init(struct btf *btf, struct bpf_object *obj) continue; codegen("\ \n\ - obj->struct_ops.%1$s = bpf_map__initial_value(obj->maps.%1$s, NULL);\n\ + obj->struct_ops.%1$s = (typeof(obj->struct_ops.%1$s))\n\ + bpf_map__initial_value(obj->maps.%1$s, NULL);\n\ \n\ ", ident); } diff --git a/tools/testing/selftests/bpf/test_cpp.cpp b/tools/testing/selftests/bpf/test_cpp.cpp index f4936834f76f46..dde0bb16e782e9 100644 --- a/tools/testing/selftests/bpf/test_cpp.cpp +++ b/tools/testing/selftests/bpf/test_cpp.cpp @@ -7,6 +7,7 @@ #include #include #include "test_core_extern.skel.h" +#include "struct_ops_module.skel.h" template class Skeleton { @@ -98,6 +99,7 @@ int main(int argc, char *argv[]) { struct btf_dump_opts opts = { }; struct test_core_extern *skel; + struct struct_ops_module *skel2; struct btf *btf; int fd; @@ -118,6 +120,9 @@ int main(int argc, char *argv[]) skel = test_core_extern__open_and_load(); test_core_extern__destroy(skel); + skel2 = struct_ops_module__open_and_load(); + struct_ops_module__destroy(skel2); + fd = bpf_enable_stats(BPF_STATS_RUN_TIME); if (fd < 0) std::cout << "FAILED to enable stats: " << fd << std::endl;