On Tue, Sep 28, 2021 at 10:52:25AM +0800, Hou Tao wrote:
> Factor out a helper bpf_prepare_st_ops_prog() to prepare trampoline
> for BPF_PROG_TYPE_STRUCT_OPS prog. It will be used by .test_run
> callback in following patch.
Thanks for the patches.
This preparation change should be the first patch instead.
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index 155dfcfb8923..002bbb2c8bc7 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -2224,4 +2224,9 @@ int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
> u32 **bin_buf, u32 num_args);
> void bpf_bprintf_cleanup(void);
>
> +int bpf_prepare_st_ops_prog(struct bpf_tramp_progs *tprogs,
> + struct bpf_prog *prog,
> + const struct btf_func_model *model,
> + void *image, void *image_end);
Move it under where other bpf_struct_ops_.*() resides in bpf.h.
> +
> #endif /* _LINUX_BPF_H */
> diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
> index 9abcc33f02cf..ec3c25174923 100644
> --- a/kernel/bpf/bpf_struct_ops.c
> +++ b/kernel/bpf/bpf_struct_ops.c
> @@ -312,6 +312,20 @@ static int check_zero_holes(const struct btf_type *t, void *data)
> return 0;
> }
>
> +int bpf_prepare_st_ops_prog(struct bpf_tramp_progs *tprogs,
> + struct bpf_prog *prog,
> + const struct btf_func_model *model,
> + void *image, void *image_end)
The existing struct_ops functions in the kernel now have naming like
bpf_struct_ops_.*(). How about renaming it to
bpf_struct_ops_prepare_trampoline()?
> +{
> + u32 flags;
> +
> + tprogs[BPF_TRAMP_FENTRY].progs[0] = prog;
> + tprogs[BPF_TRAMP_FENTRY].nr_progs = 1;
> + flags = model->ret_size > 0 ? BPF_TRAMP_F_RET_FENTRY_RET : 0;
> + return arch_prepare_bpf_trampoline(NULL, image, image_end,
> + model, flags, tprogs, NULL);
> +}
> +
> static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
> void *value, u64 flags)
> {
> @@ -368,7 +382,6 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
> const struct btf_type *mtype, *ptype;
> struct bpf_prog *prog;
> u32 moff;
> - u32 flags;
>
> moff = btf_member_bit_offset(t, member) / 8;
> ptype = btf_type_resolve_ptr(btf_vmlinux, member->type, NULL);
> @@ -430,14 +443,9 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
> goto reset_unlock;
> }
>
> - tprogs[BPF_TRAMP_FENTRY].progs[0] = prog;
> - tprogs[BPF_TRAMP_FENTRY].nr_progs = 1;
> - flags = st_ops->func_models[i].ret_size > 0 ?
> - BPF_TRAMP_F_RET_FENTRY_RET : 0;
This change can't apply to bpf-next now because
commit 356ed64991c6 ("bpf: Handle return value of BPF_PROG_TYPE_STRUCT_OPS prog")
is not pulled into bpf-next yet. Please mention the dependency
in the cover letter if it is still the case in v2.
> - err = arch_prepare_bpf_trampoline(NULL, image,
> - st_map->image + PAGE_SIZE,
> - &st_ops->func_models[i],
> - flags, tprogs, NULL);
> + err = bpf_prepare_st_ops_prog(tprogs, prog,
> + &st_ops->func_models[i],
> + image, st_map->image + PAGE_SIZE);
> if (err < 0)
> goto reset_unlock;
>
> --
> 2.29.2
>
