On Thu, Mar 17, 2022 at 05:29:47PM +0530, Kumar Kartikeya Dwivedi wrote:
> Make adjustments to the code to allow storing percpu PTR_TO_BTF_ID in a
> map. Similar to 'kptr_ref' tag, a new 'kptr_percpu' allows tagging types
> of pointers accepting stores of such register types. On load, verifier
> marks destination register as having type PTR_TO_BTF_ID | MEM_PERCPU |
> PTR_MAYBE_NULL.
>
> Cc: Hao Luo <haoluo@xxxxxxxxxx>
> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
> ---
> include/linux/bpf.h | 3 ++-
> kernel/bpf/btf.c | 13 ++++++++++---
> kernel/bpf/verifier.c | 26 +++++++++++++++++++++-----
> 3 files changed, 33 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index 702aa882e4a3..433f5cb161cf 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -161,7 +161,8 @@ enum {
> };
>
> enum {
> - BPF_MAP_VALUE_OFF_F_REF = (1U << 0),
> + BPF_MAP_VALUE_OFF_F_REF = (1U << 0),
> + BPF_MAP_VALUE_OFF_F_PERCPU = (1U << 1),
What is the use case for storing __percpu pointer into a map?
