On Tue, Feb 9, 2021 at 7:04 PM Ilya Leoshkevich <iii@xxxxxxxxxxxxx> wrote:
>
> The logic follows that of BTF_KIND_INT most of the time, some functions
> are even unified to work on both. Sanitization replaces BTF_KIND_FLOATs
> with equally-sized BTF_KIND_INTs on older kernels.
>
> Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
> ---
> tools/lib/bpf/btf.c | 85 +++++++++++++++++++++++----------
> tools/lib/bpf/btf.h | 13 +++++
> tools/lib/bpf/btf_dump.c | 4 ++
> tools/lib/bpf/libbpf.c | 32 ++++++++++++-
> tools/lib/bpf/libbpf.map | 5 ++
> tools/lib/bpf/libbpf_internal.h | 4 ++
> 6 files changed, 118 insertions(+), 25 deletions(-)
>
[...]
> @@ -2445,6 +2450,12 @@ static void bpf_object__sanitize_btf(struct bpf_object *obj, struct btf *btf)
> } else if (!has_func_global && btf_is_func(t)) {
> /* replace BTF_FUNC_GLOBAL with BTF_FUNC_STATIC */
> t->info = BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0);
> + } else if (!has_float && btf_is_float(t)) {
> + /* replace FLOAT with INT */
> + __u8 nr_bits = btf_float_bits(t);
> +
nit: no need for extra variable, just use it inline below
> + t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0);
> + *(int *)(t + 1) = BTF_INT_ENC(0, 0, nr_bits);
> }
> }
> }
> @@ -3882,6 +3893,18 @@ static int probe_kern_btf_datasec(void)
> strs, sizeof(strs)));
> }
[...]
