sched_ext: Convert scx_bpf_cid_override() to __arena array arguments

scx_bpf_cid_override() predates the cid-form arena transition and takes its
arrays as verifier-checked mem+size buffers, forcing scx_qmap to keep the
cpu_to_cid and shard_start arrays in writable bss while the rest of its
state lives in the arena. Unify on arena arguments before cid-form
schedulers start seeing real use.

BPF now translates between BPF and kernel arena addresses for __arena
arguments. Take the arrays as __arena arguments, with the counts passed in
entries. The counts now size the snapshot copies and are bounds-checked
before them.

scx_qmap moves the arrays into struct qmap_arena. As the arena is mmapped at
load, the loader populates them between load and attach instead of before
load.

The arena argument address translation is currently implemented only on
x86-64. Schedulers calling this kfunc load only there for now.

Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Tejun Heo 2026-08-12 09:55:33 -10:00
commit a05c5b5cb5
5 changed files with 84 additions and 67 deletions