On the LG Gram 2025 (Core Ultra 7 255H, Arrow Lake-H) the firmware
exposes ACPI processor objects under \_PR.CPU0..\_PR.CPU15 along
with full _PSS, _PSD, _CST, and _CPC objects. The HWP-aware
cpufreqd (Phase G.2) reads these to discover the P-state range
and the HWP activity window. Before this commit acpid exposed
nothing at /scheme/acpi/processor — cpufreqd was falling back
to its hardcoded 4-state table (2400/2000/1600/1200 kHz) on every
system including Arrow Lake.
This commit adds:
1. AcpiContext::cpu_names() — walks the symbol cache and returns
direct child names of \_PR whose serialized form is a Processor
object. Matches on the \_PR.<name> prefix (no further dots) to
avoid returning sub-objects like \_PR.CPU0._PSS.
2. HandleKind::Processor variant for the /scheme/acpi/processor/
directory and HandleKind::ProcFile for the per-CPU files. Adds
the ProcFileKind enum (Pss, Psd, Cst, Cpc) so the scheme can
route each file to its own data source.
3. kopenat() route for /scheme/acpi/processor/<cpu>/<file>
where <file> ∈ {pss, psd, cst, cpc}. Path-component match
extended to 4 elements (was 3); cpu_id parsed as u32.
4. getdents() entry for HandleKind::Processor using
self.ctx.cpu_names() — matches the same pattern as Thermal
and Power. getdents() also covers ProcFile and DmiDir (no
children; reads/writes go through kread/kwriteoff).
5. kread() entry for HandleKind::ProcFile returns a placeholder
"ACPI processor data not yet populated" line so consumers
(cpufreqd, redbear-power) can detect the path is present and
report "no data" instead of getting ENOENT. The full AML-to-
text conversion for _PSS / _PSD / _CST / _CPC is a follow-up
that walks the AML namespace and emits the canonical cpufreq
text format ("freq power latency control").
6. kread() also covers HandleKind::Processor and HandleKind::DmiDir
with EISDIR — they are directory types, not file types.
The acpid version remains at 0.1.0 — the policy in AGENTS.md
("In-house crate versioning") classifies local/sources/base/ as
an Upstream Redox fork and keeps upstream versioning. Phase G.6
adds infrastructure only, not a version bump.
Verified by: CI=1 ./local/scripts/build-redbear.sh redbear-mini
succeeded with exit 0. ISO at build/x86_64/redbear-mini.iso
(512 MB) at 2026-06-30 14:40. QEMU mini boot reaches Red Bear
login: as before. The /scheme/acpi/processor/ path is now
present and read returns the placeholder line.
Red Bear OS
c335553c7e