Re: [PATCH bpf-next] bpf: add a few more options for GCC_BPF in selftests/bpf/Makefile

[Yonghong Song <yonghong.song@linux.dev>]

On 4/24/24 1:41 AM, Jose E. Marchesi wrote:
> This little patch modifies selftests/bpf/Makefile so it passes the
> following extra options when invoking gcc-bpf:
>
>   -gbtf
>     This makes GCC to emit BTF debug info in .BTF and .BTF.ext.

Could we do if '-g' is specified, for bpf program,
btf will be automatically generated?

>
>   -mco-re
>     This tells GCC to generate CO-RE relocations in .BTF.ext.

Can we make this default? That is, remove -mco-re option. I
can imagine for any serious bpf program, co-re is a must.

>
>   -masm=pseudoc
>     This tells GCC to emit BPF assembler using the pseudo-c syntax.

Can we make it the other way round such that -masm=pseudoc is
the default? You can have an option e.g., -masm=non-pseudoc,
for the other format?

>
> Tested in bpf-next master.
> No regressions.
>
> Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
> Cc: Yonghong Song <yhs@meta.com>
> Cc: Eduard Zingerman <eddyz87@gmail.com>
> Cc: david.faust@oracle.com
> Cc: cupertino.miranda@oracle.com
> ---
>   tools/testing/selftests/bpf/Makefile | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> index edc73f8f5aef..702428021132 100644
> --- a/tools/testing/selftests/bpf/Makefile
> +++ b/tools/testing/selftests/bpf/Makefile
> @@ -442,7 +442,7 @@ endef
>   # Build BPF object using GCC
>   define GCC_BPF_BUILD_RULE
>   	$(call msg,GCC-BPF,$(TRUNNER_BINARY),$2)
> -	$(Q)$(BPF_GCC) $3 -O2 -c $1 -o $2
> +	$(Q)$(BPF_GCC) $3 -O2 -gbtf -mco-re -masm=pseudoc -c $1 -o $2
>   endef
>   
>   SKEL_BLACKLIST := btf__% test_pinning_invalid.c test_sk_assign.c