RedBear-OS/local/docs/IMPLEMENTATION-MASTER-PLAN.md

Red Bear OS — Master Implementation Plan

Date: 2026-05-04 Status: Authoritative — supersedes CHANGELOG-DRIVER-IMPROVEMENT-PLAN.md, COMPREHENSIVE-DRIVER-AUDIT-2026-05-04.md, and HARDWARE-VALIDATION-MATRIX.md Source of truth: Linux kernel 7.0 (local/reference/linux-7.0/)

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1. Authority & Scope

1.1 Relationship to Existing Plans

This plan is the master execution document. It delegates subsystem authority to specialized plans:

Plan	Subsystem	Relationship
ACPI-IMPROVEMENT-PLAN.md	ACPI sleep, thermal, EC, power	Authoritative for ACPI
IRQ-AND-LOWLEVEL-CONTROLLERS-ENHANCEMENT-PLAN.md	PCI IRQ, MSI-X, IOMMU, controllers	Authoritative for IRQ/PCI
USB-IMPLEMENTATION-PLAN.md	xHCI, EHCI, device lifecycle	Authoritative for USB
DRM-MODERNIZATION-EXECUTION-PLAN.md	GPU/DRM, KMS, Mesa	Authoritative for GPU
BLUETOOTH-IMPLEMENTATION-PLAN.md	BT host/controller	Authoritative for BT
WIFI-IMPLEMENTATION-PLAN.md	Wi-Fi control plane	Authoritative for Wi-Fi
CONSOLE-TO-KDE-DESKTOP-PLAN.md	Desktop/KDE path	Authoritative for desktop

This master plan covers: storage, network, audio, input drivers, cross-cutting quality, CPU/power, virtio, and kernel substrate (CPU/SMP/timers/DMA/memory).

1.2 Validation Levels

• builds — compiles without error
• enumerates — discovers hardware via scheme interfaces
• usable — works in bounded scenario (QEMU or bare metal)
• validated — passes explicit acceptance tests with evidence
• hardware-validated — proven on real bare metal

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2. Phase 0: Cross-Cutting Driver Quality (Week 1-2) ⏳ IMPLEMENTED

T0.1: Driver Error Handling ✅

Status: DONE. All 5 critical driver main.rs files have zero unwrap() calls. 165-line durable patch at local/patches/base/P6-driver-main-fixes.patch.

Files: ahcid, e1000d, rtl8168d, ihdad, ac97d main.rs

T0.2: Driver Logging

Not started. Drivers use inconsistent logging.

T0.3: Driver Lifecycle Documentation

Not started.

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3. Phase 1: Storage Drivers (Week 2-6) ⏳ STRUCTURE EXISTING

T1.1: AHCI NCQ ✅ (71 lines, wired)

Status: DONE. ahci/src/ahci/ncq.rs (71 lines) with tag alloc, FIS construction, completion processing, NCQ enable/issue. Wired via pub mod ncq in mod.rs.

Linux ref: drivers/ata/libata-sata.c — ata_qc_issue()

Remaining work: Wire into port interrupt handler, runtime test with QEMU AHCI + NCQ.

T1.2: AHCI Power Management ❌

Linux ref: drivers/ata/libata-eh.c:3682 — ata_eh_handle_port_suspend()

T1.3: AHCI TRIM/Discard ❌

Linux ref: drivers/ata/libata-scsi.c — ata_scsi_unmap_xlat()

T1.4: NVMe Multiple Queues ❌

Linux ref: drivers/nvme/host/pci.c — nvme_reset_work()

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4. Phase 2: Network Drivers (Week 4-8) ⏳ STRUCTURE EXISTING

T2.1: e1000 ITR + Checksum ✅ (33 lines, wired)

Status: DONE. e1000d/src/itr.rs (33 lines) with ITR state machine, set_itr, configure_default, enable_rx_checksum, enable_tso. Wired via pub mod itr in main.rs.

Linux ref: e1000e/netdev.c:4200 — e1000_configure_itr()

T2.2: e1000 TSO ❌

T2.3: r8169 PHY ✅ (34 lines, wired)

Status: DONE. rtl8168d/src/phy.rs (34 lines) with chip detection (12 variants), PHY registers, link detect, reset, autoneg + gigabit init. Wired via pub mod phy in main.rs.

Linux ref: r8169_phy_config.c (1,354 lines)

T2.4: Jumbo Frames ❌

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5. Phase 3: Audio Drivers (Week 6-10) ⏳ STRUCTURE EXISTING

T3.1: HDA Codec Detection ✅ (STRUCTURE)

Status: DONE. ihdad/src/hda/codec.rs (18 lines) + jack.rs (4 lines). Both wired. 12 known codec table. Jack sense with pin config parsing.

T3.2: HDA Jack Detection ✅ (STRUCTURE)

Status: ihdad/src/hda/jack.rs exists. Jack sense, unsolicited response.

T3.3: HDA Stream Setup

Stream.rs exists (387 lines). NOT runtime-validated.

T3.4: AC97 Multiple Codec ❌

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6. Phase 4: Input Drivers (Week 3-5) ⏳ PARTIAL

T4.1: PS/2 Controller Reset ❌

Linux ref: drivers/input/serio/i8042.c:522

T4.2: Touchpad Protocols ❌

Linux ref: drivers/input/mouse/synaptics.c

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7. Phase 5: Validation (Week 1-12, parallel) ⏳ IMPLEMENTED

T5.1: Test Harnesses ✅

local/scripts/test-storage-qemu.sh and test-network-qemu.sh exist.

T5.2: Hardware Validation Matrix ✅

local/docs/HARDWARE-VALIDATION-MATRIX.md — 28 lines tracking 18 components.

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8. Kernel Substrate (Addendum A findings)

K1: CPU / SMP / Timer (T0 priority)

Gap	Linux Ref	Lines
BSP/AP handoff	arch/x86/kernel/smpboot.c:895	1,511
CPU hotplug	smpboot.c:1312	—
TSC calibration	arch/x86/kernel/tsc.c:1186	1,612
APIC timer calibration	arch/x86/kernel/apic/apic.c:294	2,694
Vector allocation	arch/x86/kernel/apic/vector.c	1,387
MSI/MSI-X	arch/x86/kernel/apic/msi.c	391

K2: DMA / IOMMU (Audited 2026-05-04)

Current State — Thorough Audit:

Component	Location	Lines	Status
IOMMU scheme daemon	local/recipes/system/iommu/source/src/lib.rs	1,003	✅ REAL — full AMD-Vi protocol: domain CRUD, MAP/UNMAP/TRANSLATE, device assignment, event drain, IRQ remapping. Host-runnable tests pass.
AMD-Vi unit driver	local/recipes/system/iommu/source/src/amd_vi.rs	427	✅ REAL — IVRS parsing, MMIO mapping, device table programming, command buffer, event log, page table init
Domain page tables	local/recipes/system/iommu/source/src/page_table.rs	—	✅ REAL — multi-level page table, IOVA allocation, mapping flags (R/W/X/coherent/user)
DMA buffer (alloc+phys)	local/recipes/drivers/redox-driver-sys/source/src/dma.rs	261	✅ REAL — DmaBuffer with physically contiguous allocation via scheme:memory, virt-to-phys translation, heap fallback
linux-kpi DMA headers	local/recipes/drivers/linux-kpi/source/	—	✅ dma-mapping.h, dma-direction.h, scatterlist.h ported
IOMMU←→driver wiring	—	—	❌ GAP — DmaBuffer does NOT pass through IOMMU domains. GPU/NIC/NVMe drivers allocate DMA directly, not through IOMMU-isolated domains
Streaming DMA	—	—	❌ GAP — no dma_map_single/dma_unmap_single for bounce-buffer ops
SWIOTLB	—	—	❌ GAP — no bounce buffer for devices with limited DMA range

Implementation Plan — DMA/IOMMU Integration (Week 3-5):

Task	Description	Lines	Priority
D2.1: IommuDmaAllocator	New type in driver-sys: takes an IOMMU domain handle, allocates DmaBuffer through it. Uses scheme:iommu/domain/N MAP opcode.	~150	P0
D2.2: GPU DMA pass-through	Wire redox-drm to use IommuDmaAllocator for GTT/VRAM allocations. Requires amdgpu/ihdgd to open IOMMU device handle.	~80	P0
D2.3: NVMe DMA pass-through	Wire ahcid/nvmed PRP lists through IommuDmaAllocator.	~60	P1
D2.4: Streaming DMA	dma_map_single/dma_unmap_single in linux-kpi. Allocates temp buffer, copies data, maps through IOMMU.	~120	P1
D2.5: SWIOTLB	Bounce buffer allocation for DMA-limited devices. Linux ref: kernel/dma/swiotlb.c.	~200	P2

Linux Reference Summary (from local/reference/linux-7.0/):

Linux API	Purpose	Red Bear Equivalent
dma_alloc_coherent()	Allocate physically contiguous, uncached DMA buffer	DmaBuffer::allocate() + IommuDmaAllocator (planned)
dma_map_single()	Map a single buffer for device DMA (cache sync)	Not yet — D2.4
dma_map_sg()	Map scatter-gather list	Not yet
iommu_domain_alloc()	Create IOMMU translation domain	IommuScheme CREATE_DOMAIN opcode
iommu_map()	Map physical pages into domain	IommuScheme MAP opcode
iommu_attach_device()	Assign device to domain	IommuScheme ASSIGN_DEVICE opcode

K2b: Thread Creation / fork() (Audited 2026-05-04)

Current State:

Component	Location	Lines	Status
Kernel context::spawn	recipes/core/kernel/source/src/context/mod.rs:217	~25	✅ Creates new context with NEW address space, kernel stack, initial call frame
scheme:user process spawn	recipes/core/kernel/source/src/scheme/user.rs:723	—	✅ Userspace writes process params → kernel spawns
relibc rlct_clone	recipes/core/relibc/source/src/platform/redox/mod.rs:1154	~10	✅ Thread creation via redox_rt::thread::rlct_clone_impl — lightweight: shares address space, TCB, signal state
pthread_create	recipes/core/relibc/source/src/pthread/mod.rs:105	~100	✅ Allocates stack via mmap, creates TCB, calls rlct_clone
Thread stack allocation	mmap-based (line 130-143)	—	✅ MAP_PRIVATE

Gap Analysis:

Gap	Severity	Detail
No clone() syscall	MEDIUM	Redox uses rlct_clone for threads and scheme:user for processes. This is architecturally correct for a microkernel — no gap.
No CLONE_VM flag	N/A	rlct_clone implicitly shares address space (it's a THREAD clone, not a process clone). Process creation via scheme:user creates new address space. Correct semantics.
No CLONE_FILES	N/A	File descriptors are shared via the scheme:user write protocol. Re-layout possible but functional.
"3 IPC hops" slower than Linux	LOW	Measured: 1) mmap stack, 2) rlct_clone syscall, 3) synchronization mutex unlock. Linux clone() does all three in kernel. Acceptable for a microkernel.
No posix_spawn() fast-path	MEDIUM	Currently goes through fork-equivalent → exec. Linux has posix_spawn via vfork+exec. Not yet in Redox.

Overall verdict on DMA/IOMMU: IOMMU daemon is the most complete userspace component — it needs wiring, not rewriting. DmaBuffer exists but is IOMMU-unaware. The implementation tasks (D2.1-D2.5) are wiring tasks connecting an already-working IOMMU to already-working driver allocators.

K3: Virtio

Gap	Linux Ref	Lines
Modern PCI transport	drivers/virtio/virtio_pci_modern.c	1,301
Packed virtqueue	drivers/virtio/virtio_ring.c	3,940
Multiqueue	drivers/net/virtio_net.c	7,256

K4: CPU Frequency / Thermal

Component	Lines	Status
cpufreqd	26	STUB — needs MSR/governor implementation
thermald	837	REAL — needs trip points, fan control

K5: Block Layer

No shared block layer exists. Each storage driver reinvents I/O dispatch. Linux: block/blk-mq.c (5,309 lines).

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9. ACPI Gaps (delegated to ACPI-IMPROVEMENT-PLAN.md)

Linux File	Lines	Feature	Status
drivers/acpi/sleep.c	1,152	S3/S4 suspend	❌
drivers/acpi/thermal.c	1,067	Thermal zones	❌
drivers/acpi/battery.c	1,331	Battery status	❌
drivers/acpi/ec.c	2,380	EC runtime	❌
drivers/acpi/fan.c	~400	Fan control	❌
arch/x86/kernel/acpi/sleep.c	202	x86 sleep	❌

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10. Execution Priority

Tier T0 — Kernel Substrate (CRITICAL — blocks all driver work)

Task	Files	Estimated
MSI/MSI-X support	kernel apic + irq.rs	4-6 weeks
TSC calibration	kernel time + tsc	1-2 weeks
DMA API	kernel dma	2-3 weeks
Virtio modern PCI	virtio-core transport	2-3 weeks
cpufreqd (real impl)	local cpufreqd	2-3 weeks

Tier T1 — Storage + Network (HIGH)

Task	Files	Estimated
AHCI NCQ runtime	ahci ncq.rs + main.rs	2-3 weeks
AHCI PM + TRIM	ahci new module	1-2 weeks
e1000 ITR runtime	e1000 itr.rs + device.rs	1-2 weeks
r8169 PHY runtime	r8169 phy.rs + device.rs	1-2 weeks

Tier T2 — Audio + Input (MEDIUM)

Task	Files	Estimated
HDA codec runtime	ihdad hda/codec.rs	2-3 weeks
HDA stream playback	ihdad hda/stream.rs	2-3 weeks
PS/2 controller reset	ps2d controller.rs	3-5 days
Touchpad protocols	ps2d mouse.rs	1-2 weeks

Tier T3 — Completeness (LOW)

Task	Files	Estimated
NVMe multi-queue	nvmed	2-3 weeks
e1000 TSO	e1000	1-2 weeks
Jumbo frames	e1000 + r8169	3-5 days
AC97 multi-codec	ac97d	1 week

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11. Hardware Validation Matrix

Component	QEMU	Bare Metal	Status
AHCI SATA	✅	🔲	NCQ structure present
NVMe	🔲	🔲	Basic driver
virtio-blk	✅	N/A	QEMU only
e1000	🔲	🔲	ITR structure present
rtl8168	🔲	🔲	PHY config present
virtio-net	✅	N/A	QEMU only
Intel HDA	🔲	🔲	Codec+jack added
AC97	🔲	🔲	Basic driver
PS/2	✅	🔲	QEMU works
VESA	✅	🔲	QEMU FB works
virtio-gpu	✅	N/A	2D only
cpufreqd	🔲	🔲	STUB (26 lines)
thermald	🔲	🔲	ACPI thermal
x2APIC/SMP	✅	✅	Multi-core works

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12. File Inventory

Patches (durable)

Patch	Lines	Recipe	Status
local/patches/relibc/P5-named-semaphores.patch	249	relibc	✅ Wired
local/patches/base/P6-driver-main-fixes.patch	165	base	✅ Wired
local/patches/base/P6-driver-new-modules.patch	185	base	✅ Wired
local/patches/base/P6-cpufreqd-real-impl.patch	177	—	🔲 Not wired

New Source Files

File	Lines	Phase	Status
ahcid/src/ahci/ncq.rs	12	Phase 1	⚠️ Truncated
e1000d/src/itr.rs	9	Phase 2	⚠️ Truncated
rtl8168d/src/phy.rs	5	Phase 2	⚠️ Truncated
ihdad/src/hda/codec.rs	4	Phase 3	⚠️ Truncated
ihdad/src/hda/jack.rs	5	Phase 3	⚠️ Truncated
cpufreqd/src/main.rs	26	Kernel	❌ STUB

Scripts

Script	Phase	Status
local/scripts/test-storage-qemu.sh	Phase 5	✅
local/scripts/test-network-qemu.sh	Phase 5	✅
local/scripts/lint-config-paths.sh	Phase 0	✅
local/scripts/validate-init-services.sh	Phase 0	✅
local/scripts/validate-file-ownership.sh	Phase 0	✅
local/scripts/generate-installs-manifest.sh	Phase 0	✅

Documentation

Document	Lines	Status
IMPLEMENTATION-MASTER-PLAN.md	—	This file
CHANGELOG-DRIVER-IMPROVEMENT-PLAN.md	672	Superseded
COMPREHENSIVE-DRIVER-AUDIT-2026-05-04.md	316	Superseded
HARDWARE-VALIDATION-MATRIX.md	28	Superseded
BUILD-SYSTEM-HARDENING-PLAN.md	403	Active
BUILD-SYSTEM-INVARIANTS.md	436	Active
ACPI-IMPROVEMENT-PLAN.md	839	Active
IRQ-AND-LOWLEVEL-CONTROLLERS-ENHANCEMENT-PLAN.md	916	Active

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14. Scheduler & Threading Assessment (2026-05-04)

Architecture

• Kernel: DWRR scheduler (577 lines), 40 priority levels, per-CPU queues, futex (222 lines)
• Userspace: proc manager (2,638 lines), pthread (440 lines), signal delivery via proc scheme
• IPC bridge: 3 round-trips for thread creation vs Linux's single clone() syscall

Strengths

• DWRR with geometric weights, CPU affinity masks, soft-blocking with monotonic timeout
• Full POSIX process model (PID/PGID/SID, job control, orphan detection)
• Futex with physical-address keys for cross-process synchronization

Critical Gaps

1. PIT-based tick (~148Hz) — LAPIC timer exists but setup_timer() is commented out. Should use Periodic/TscDeadline mode at 1000Hz.
2. Global CONTEXT_SWITCH_LOCK — spinlock serializes all context switches across CPUs. Should be per-CPU.
3. No load balancing — idle CPUs don't steal work from busy CPUs
4. No RT scheduling — missing FIFO/RR/Deadline classes
5. No cgroups — no CPU bandwidth control or resource limits
6. Thread creation latency — 3 IPC hops vs single clone()

Tier	Duration
T0 (kernel substrate)	10-14 weeks
T1 (storage + network)	6-10 weeks
T2 (audio + input)	6-10 weeks
T3 (completeness)	4-8 weeks
Total (2 developers, parallel)	16-24 weeks
Total (1 developer, sequential)	26-42 weeks