Time is a kernel concern in danos: the kernel owns the scheduling timer and
already exposes monotonic time via the clock/sleep/timer_bind syscalls, so a
userspace time service would be a redundant, slower path. This adds the generic
runtime.time module over those syscalls, retires the two demonstration drivers,
reorganizes the milestone docs, and makes the monotonic clock correct on Intel,
AMD, and inside any VM.
runtime.time (library/runtime/time.zig)
- Instant/Duration interface: now, sleep, spin, after, monotonicNanos, available
- a thin layer over system.clock/sleep/timerOnce; unit-tested arithmetic
Remove the demo drivers hpet and bus (a teaching example belongs in the docs,
not shipped in the tree)
- system/drivers/ now holds only real drivers: pci-bus, ps2-bus, usb-xhci-bus
- device-manager end-to-end test repointed to pci-bus (asserts on kernel state:
the process table and the device tree, not a racy serial marker)
- device_register containment moved to a new in-kernel `containment` test
- the driver-model worked example moved inline into docs/drivers.md
Reorganize milestone docs into topic docs
- m17-m18 / m19-m20 / m21 plans dissolved into process-lifecycle, device-manager,
discovery, and acpi docs; new docs/power.md and docs/timers.md; ~20 citations
repointed; plan docs deleted
TSC reliability (apic.zig, smp.zig, cpu.zig, kernel.zig)
- check the invariant-TSC bit (CPUID 0x80000007 EDX[8]) on Intel and AMD
- cross-core "warp" check at SMP bring-up, pairwise BSP<->AP as each core comes up
- fall back to the HPET clocksource when the TSC is not invariant (a bare VM) or
not synchronized (a warp), switched continuously so time never jumps
- boot log reports the outcome; new tsc-sync test exercises the TSC + warp path
Verified: zig build; zig build test; 60/60 QEMU cases (incl. new containment and
tsc-sync).
resilience.md: steps 1-4 of the ladder are built — supervision, exit
reasons, restart with backoff, crash-loop caps, all proven by scenario;
what remains is scope, not mechanism. README statuses follow. drivers.md
gains the driver-contract section (harness, hello, crash-freely). The
M19-M20 plan pre-settles three things the loop would otherwise have had
to decide alone: the memory-map pass-through for apertures, the manager
spawning 'discovery' from M20.1, and hid[8] riding ChildAdded for ACPI
string identity until the FDT widening.
A CPU exception raised in ring 3 by a scheduled process now kills that
process - IRQ bindings, IPC handles, and address space reclaimed, a
client it owed a reply to failed with the new -EPEER instead of hung -
and the core reschedules (docs/resilience.md step 2). Kernel-mode
faults, NMI, double fault, and machine check stay terminal, as does the
borrowed-thread isolation probe. Proven by the new fault-recovery QEMU
test: init keeps heartbeating after a process page-faults to death.
Daniel Samson
Daniel Samson