[PATCH v2 bpf-next] Add CONFIG_DEBUG_INFO_BTF check to bpftool feature command

[PATCH v2 bpf-next] Add CONFIG_DEBUG_INFO_BTF check to bpftool feature command

[grantseltzer]

This adds the CONFIG_DEBUG_INFO_BTF kernel compile option to output of
the bpftool feature command. This is relevant for developers that want
to use libbpf to account for data structure definition differences
between kernels.

Signed-off-by: grantseltzer <grantseltzer@gmail.com>
---
 tools/bpf/bpftool/feature.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
index 359960a8f..34343e7fa 100644
--- a/tools/bpf/bpftool/feature.c
+++ b/tools/bpf/bpftool/feature.c
@@ -336,6 +336,8 @@ static void probe_kernel_image_config(const char *define_prefix)
 		{ "CONFIG_BPF_JIT", },
 		/* Avoid compiling eBPF interpreter (use JIT only) */
 		{ "CONFIG_BPF_JIT_ALWAYS_ON", },
+		/* Enable using BTF debug information */
+		{ "CONFIG_DEBUG_INFO_BTF", },
 
 		/* cgroups */
 		{ "CONFIG_CGROUPS", },
-- 
2.29.2

Re: [PATCH v2 bpf-next] Add CONFIG_DEBUG_INFO_BTF check to bpftool feature command

[Quentin Monnet]

2021-02-20 05:13 UTC+0000 ~ grantseltzer <grantseltzer@gmail.com>
> This adds the CONFIG_DEBUG_INFO_BTF kernel compile option to output of
> the bpftool feature command. This is relevant for developers that want
> to use libbpf to account for data structure definition differences
> between kernels.
> 
> Signed-off-by: grantseltzer <grantseltzer@gmail.com>
> ---
>  tools/bpf/bpftool/feature.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
> index 359960a8f..34343e7fa 100644
> --- a/tools/bpf/bpftool/feature.c
> +++ b/tools/bpf/bpftool/feature.c
> @@ -336,6 +336,8 @@ static void probe_kernel_image_config(const char *define_prefix)
>  		{ "CONFIG_BPF_JIT", },
>  		/* Avoid compiling eBPF interpreter (use JIT only) */
>  		{ "CONFIG_BPF_JIT_ALWAYS_ON", },
> +		/* Enable using BTF debug information */
> +		{ "CONFIG_DEBUG_INFO_BTF", },

Nit: The comment is slightly misleading, you can use BTF to list program
C instructions or map structures without this option for example. Maybe
something like this?

	/* Kernel BTF debug information available */

Thanks for the patch!
Quentin