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vasilito 50b731f1b7 Red Bear OS — microkernel OS in Rust, based on Redox

Derivative of Redox OS (https://www.redox-os.org) adding:
- AMD GPU driver (amdgpu) via LinuxKPI compat layer
- ext4 filesystem support (ext4d scheme daemon)
- ACPI fixes for AMD bare metal (x2APIC, DMAR, IVRS, MCFG)
- Custom branding (hostname, os-release, boot identity)

Build system is full upstream Redox with RBOS overlay in local/.
Patches for kernel, base, and relibc are symlinked from local/patches/
and protected from make clean/distclean. Custom recipes live in
local/recipes/ with symlinks into the recipes/ search path.

Build:  make all CONFIG_NAME=redbear-full
Sync:   ./local/scripts/sync-upstream.sh

2026-04-12 19:05:00 +01:00

9.3 KiB

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02 — Gap Analysis & Roadmap

Overview

This document maps the distance between current Redox OS 0.9.0 and three goals:

Wayland compositor support → see 03-WAYLAND-ON-REDOX.md
KDE Plasma desktop → see 05-KDE-PLASMA-ON-REDOX.md
Linux driver compatibility layer → see 04-LINUX-DRIVER-COMPAT.md

Dependency Chain: Hardware → KDE Desktop

┌─────────────────────────────────────────────────────────┐
│                    KDE Plasma Desktop                     │
│  (KWin compositor, Plasma Shell, Qt, KDE Frameworks)    │
├─────────────────────────────────────────────────────────┤
│                    Wayland Protocol                       │
│  (libwayland, wayland-protocols, compositor)             │
├─────────────────────────────────────────────────────────┤
│                    Graphics Stack                         │
│  (Mesa3D OpenGL/Vulkan, GBM, libdrm, GPU driver)        │
├─────────────────────────────────────────────────────────┤
│                    Kernel Interfaces                      │
│  (DRM/KMS, GEM/TTM, DMA-BUF, evdev, udev)              │
├─────────────────────────────────────────────────────────┤
│                    Hardware                               │
│  (GPU: AMD/Intel/NVIDIA, Input: keyboard/mouse/touch)   │
└─────────────────────────────────────────────────────────┘

Gap Matrix with Concrete File References

Layer 1: POSIX Interfaces (relibc)

API	Status	Where to implement	Effort
`signalfd`/`signalfd4`	Missing	`relibc/src/header/signal/mod.rs` + `signal/types.rs`	Medium
`timerfd_create/settime/gettime`	Missing	`relibc/src/header/sys_timerfd/` (NEW directory)	Medium
`eventfd`/`eventfd_read`/`eventfd_write`	Missing	`relibc/src/header/sys_eventfd/` (NEW directory)	Low
`F_DUPFD_CLOEXEC`	Missing	`relibc/src/header/fcntl/mod.rs` (add constant)	Low
`MSG_CMSG_CLOEXEC`	Missing	`relibc/src/header/sys_socket/mod.rs`	Low
`MSG_NOSIGNAL`	Missing	`relibc/src/header/sys_socket/mod.rs`	Low
`open_memstream`	Missing	`relibc/src/header/stdio/src.rs`	Low
UDS + FD passing	Done	Already implemented	—
`epoll` (event scheme)	Done	Redox `scheme:event`	—
`mmap`/`mprotect`	Done	Kernel syscalls	—
`fork`/`exec`	Done	Userspace via `thisproc:` scheme	—

Proof of gap: See recipes/wip/wayland/libwayland/redox.patch — all 7 missing APIs are stubbed there.

Layer 2: GPU / Display Infrastructure

Component	Status	Where to implement	Concrete doc
DRM/KMS scheme	Missing	New daemon: `redox-drm` crate	04 §3
GPU driver (Intel)	Experimental modeset only	`redox-drm/src/drivers/intel/`	04 §3
GEM buffers	Missing	`redox-drm/src/gem.rs`	04 §3
DMA-BUF sharing	Missing	`redox-drm/src/dmabuf.rs`	04 §3
Mesa hardware backend	Missing	Mesa winsys for Redox DRM	03 §3.4
GPU OpenGL	Software only	Blocked on GPU driver	04

Layer 3: Input Stack

Component	Status	Where to implement	Concrete doc
evdev daemon	Missing	New: `recipes/core/evdevd/`	03 §2
udev shim	Missing	New: `recipes/wip/wayland/udev-shim/`	03 §2
libinput	Missing	`recipes/wip/wayland/libinput/` (NEW)	03 §2
XKB layouts	Done	`xkeyboard-config` ported	—
seatd	Recipe exists, untested	`recipes/wip/wayland/seatd/`	—

Layer 4: Wayland Protocol

Component	Status	Recipe	Blocker
libwayland	Patched, broken timers	`recipes/wip/wayland/libwayland/`	Layer 1 POSIX gaps
cosmic-comp	No keyboard input	`recipes/wip/wayland/cosmic-comp/`	Layer 3 libinput
smallvil (Smithay)	Basic, slow	`recipes/wip/wayland/smallvil/`	Layer 2+3 for DRM+input
wlroots/sway/hyprland	Not tested	`recipes/wip/wayland/wlroots/`	Layer 2+3

Layer 5: KDE Plasma

Component	Status	Concrete doc
Qt 6	Not ported	05 Phase KDE-A
KDE Frameworks	Not ported	05 Phase KDE-B
KWin	Not ported	05 Phase KDE-C
Plasma Shell	Not ported	05 Phase KDE-C
D-Bus	Ported	`config/x11.toml` has it working

Layer 6: Linux Driver Compatibility

Component	Status	Concrete doc
`redox-driver-sys` crate	Not started	04 §3
`linux-kpi` C headers	Not started	04 §3
i915 C driver port	Not started	04 §4
amdgpu C driver port	Not started	04 §5

Concrete Roadmap with Milestones

Milestone M1: "libwayland works natively" (2-4 weeks)

Implement 7 POSIX APIs in relibc (see Layer 1 table)
Remove redox.patch from libwayland recipe
Test: wayland-rs_simple_window runs without crashes
Delivers: libwayland, wayland-protocols, libdrm all build natively

Milestone M2: "Input works via libinput" (4-6 weeks after M1)

Build evdevd daemon (reads Redox input schemes, exposes /dev/input/eventX)
Build udev-shim for hotplug
Port libinput with evdev backend
Test: libinput list-devices shows keyboard and mouse
Delivers: Full input stack for any Wayland compositor

Milestone M3: "Display output via DRM" (8-12 weeks, parallel with M2)

Build redox-driver-sys crate
Build redox-drm daemon with Intel native driver
Register scheme:drm/card0
Test: modetest -M intel shows display modes
Delivers: KMS modesetting, hardware display control

Milestone M4: "Wayland compositor with input + display" (2-4 weeks after M2+M3)

Add Redox backends to Smithay (input + DRM + EGL)
Build smallvil with Redox backends
Test: Compositor takes over display, keyboard/mouse work
Delivers: First fully functional Wayland compositor on Redox

Milestone M5: "Qt application runs" (6-8 weeks after M4)

Port qtbase with Wayland QPA
Port qtwayland, qtdeclarative
Test: Qt widget app shows window on compositor
Delivers: Qt development on Redox

Milestone M6: "KDE app runs" (6-8 weeks after M5)

Port KDE Frameworks (25 frameworks)
Port one KDE app (e.g., Kate)
Test: Kate editor opens and edits a file
Delivers: KDE application ecosystem begins

Milestone M7: "KDE Plasma desktop" (4-6 weeks after M6)

Port KWin (DRM/Wayland backend)
Port Plasma Shell
Create config/kde.toml
Test: Full Plasma session boots
Delivers: KDE Plasma as a usable desktop

Milestone M8: "Linux GPU drivers" (8-12 weeks, parallel track from M3)

Build linux-kpi C headers
Port i915 as proof of concept
Port amdgpu for AMD support
Test: amdgpu drives AMD GPU on Redox
Delivers: Broad GPU hardware support via Linux driver ports

Parallel Execution Plan

Week 1-4:     M1 (relibc POSIX gaps)
Week 3-12:    M2 (evdev input) ──── parallel ──── M3 (DRM/KMS)
Week 13-16:   M4 (Wayland compositor = M2 + M3 + M1)
Week 13-24:   M8 (Linux driver compat, parallel with M4-M6)
Week 17-24:   M5 (Qt Foundation)
Week 25-32:   M6 (KDE Frameworks)
Week 33-38:   M7 (Plasma Desktop)

Total to KDE Plasma: ~38 weeks (~9 months) with 2 developers. Total to Linux driver compat: ~24 weeks (~6 months) in parallel.

Critical Path

M1 (POSIX) ──────────────────────────────────────┐
                                                   │
M3 (DRM/KMS) ─────────── M4 (Compositor) ── M5 (Qt) ── M6 (KDE) ── M7 (Plasma)
       │                  ↑                      │
M2 (Input) ──────────────┘                       M8 (Linux drivers, parallel)

Shortest path to a desktop: M1 → M2 → M3 (parallel) → M4 → M5 → M6 → M7 Shortest path to GPU drivers: M3 → M8 (can start as soon as redox-driver-sys exists)

9.3 KiB Raw Blame History