Re: [PATCH v3] bpf: Remove custom build rule

[Masahiro Yamada]

On Thu, Aug 29, 2024 at 3:11 AM Alexey Gladkov <legion@xxxxxxxxxx> wrote:
>
> According to the documentation, when building a kernel with the C=2
> parameter, all source files should be checked. But this does not happen
> for the kernel/bpf/ directory.
>
> $ touch kernel/bpf/core.c
> $ make C=2 CHECK=true kernel/bpf/core.o
>
> Outputs:
>
>   CHECK   scripts/mod/empty.c
>   CALL    scripts/checksyscalls.sh
>   DESCEND objtool
>   INSTALL libsubcmd_headers
>   CC      kernel/bpf/core.o
>
> As can be seen the compilation is done, but CHECK is not executed. This
> happens because kernel/bpf/Makefile has defined its own rule for
> compilation and forgotten the macro that does the check.
>
> There is no need to duplicate the build code, and this rule can be
> removed to use generic rules.
>
> Signed-off-by: Alexey Gladkov <legion@xxxxxxxxxx>


Acked-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>


> ---
>  kernel/bpf/Makefile       | 6 ------
>  kernel/bpf/btf_iter.c     | 2 ++
>  kernel/bpf/btf_relocate.c | 2 ++
>  kernel/bpf/relo_core.c    | 2 ++
>  4 files changed, 6 insertions(+), 6 deletions(-)
>  create mode 100644 kernel/bpf/btf_iter.c
>  create mode 100644 kernel/bpf/btf_relocate.c
>  create mode 100644 kernel/bpf/relo_core.c
>
> diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile
> index 0291eef9ce92..9b9c151b5c82 100644
> --- a/kernel/bpf/Makefile
> +++ b/kernel/bpf/Makefile
> @@ -52,9 +52,3 @@ obj-$(CONFIG_BPF_PRELOAD) += preload/
>  obj-$(CONFIG_BPF_SYSCALL) += relo_core.o
>  obj-$(CONFIG_BPF_SYSCALL) += btf_iter.o
>  obj-$(CONFIG_BPF_SYSCALL) += btf_relocate.o
> -
> -# Some source files are common to libbpf.
> -vpath %.c $(srctree)/kernel/bpf:$(srctree)/tools/lib/bpf
> -
> -$(obj)/%.o: %.c FORCE
> -       $(call if_changed_rule,cc_o_c)
> diff --git a/kernel/bpf/btf_iter.c b/kernel/bpf/btf_iter.c
> new file mode 100644
> index 000000000000..eab8493a1669
> --- /dev/null
> +++ b/kernel/bpf/btf_iter.c
> @@ -0,0 +1,2 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +#include "../../tools/lib/bpf/btf_iter.c"
> diff --git a/kernel/bpf/btf_relocate.c b/kernel/bpf/btf_relocate.c
> new file mode 100644
> index 000000000000..8c89c7b59ef8
> --- /dev/null
> +++ b/kernel/bpf/btf_relocate.c
> @@ -0,0 +1,2 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +#include "../../tools/lib/bpf/btf_relocate.c"
> diff --git a/kernel/bpf/relo_core.c b/kernel/bpf/relo_core.c
> new file mode 100644
> index 000000000000..6a36fbc0e5ab
> --- /dev/null
> +++ b/kernel/bpf/relo_core.c
> @@ -0,0 +1,2 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +#include "../../tools/lib/bpf/relo_core.c"
> --
> 2.46.0
>


-- 
Best Regards
Masahiro Yamada