libbpf: Add support for global percpu data

Add support for global percpu data in libbpf by adding a new ".percpu"
section, similar to ".data". It enables efficient handling of percpu
global variables in bpf programs.

When generating loader for lightweight skeleton, update the percpu_array
map used for global percpu data using BPF_F_ALL_CPUS, in order to update
values across all CPUs using one value slot.

Unlike global data, the mmaped data for global percpu data will be marked
as read-only after populating the percpu_array map. Thereafter, users can
read those initialized percpu data after loading prog. If they want to
update the percpu data after loading prog, they have to update the
percpu_array map using key=0 instead.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260813152324.97937-6-leon.hwang@linux.dev

0 files changed, 0 insertions, 0 deletions