AML method evaluation now runs in userspace touching real hardware: the
service builds an interpreter with a ring-3 Hal (port I/O routed through
its claimed acpi-tables node; a scratch page backs SystemMemory maps so a
stray OperationRegion degrades to zeros instead of faulting a process
that cannot map arbitrary physical memory). It walks the namespace and,
for each present _HID device that is not a PCI root, evaluates _CRS,
registers it under acpi-tables, and reports it with its EISA-decoded hid.
Containment for this needed the broker's irq check to become range-based
— an interrupt line is still indivisible, but a parent may own a range,
so the acpi-tables node's broad irq window contains its children's legacy
lines (a length-1 range is exactly the old equality, so single-irq
parents are unaffected). ChildAdded gained a hid field for firmware
string identity. Matching those reports to drivers stays off until M20.3,
so ps2-bus still comes up via the kernel path — no regression. The
acpi-report scenario proves the PS/2 keyboard (io 0x60/0x64 + IRQ) and
mouse (IRQ) are reported with their resources. Suite 57/57.
The AML module becomes a build module compiled into both the kernel (for
the \_S5 sleep state it still needs) and the new acpi service — one
source, two builds, no fork. The kernel publishes a single acpi-tables
node: the DSDT/SSDT blobs as memory resources, a broad io_port grant (the
honest trust boundary — firmware AML names whatever ports it chose, known
only after parsing), and the SCI for the M21 event track. The acpi
service claims the node, maps each blob through the ordinary mmio grant
(which preserves the sub-page offset onto the bytecode), and runs the
same parser the kernel does. It self-verifies its namespace Device count
against the kernel's — 34 = 34 — deterministically via an argv the
acpi-parse test passes, so no racing the shared serial buffer. Parse-only
touches no hardware; OperationRegion evaluation waits for _CRS/_STA in
M20.2. The manager spawns 'discovery' (the neutral ramdisk name) at
startup. Suite 56/56.
system/services/acpi and system/services/fdt exist as documented
placeholders (silent clean-exit mains; the headers say exactly what each
becomes and why). The build's -Ddiscovery=acpi|fdt option fills the
ramdisk's neutral 'discovery' slot — the device manager will spawn
"discovery" by that name in M20.3 and never learn which firmware it is
on (m19-m20-plan.md decision 7). x86 defaults to acpi; the aarch64
target flips the default when it lands.
Daniel Samson