/etc/init.csv and /etc/devices.csv become /system/configuration/*.csv (the
repo's etc/ moves to system/configuration/, mirroring the runtime tree),
/var/log becomes /system/logs, and /mnt/usb becomes /volumes/usb. The
kernel VFS gains a carve-out so FAT may serve exactly /system/configuration
and /system/logs beneath the initrd-backed /system while /system and /test
themselves stay unshadowable; FAT's single /var mount splits into those two
rewritten mounts. The kvfs readdir check learns /system's third child and
the ramdisk spawn sweep skips the configuration tree.
Suite 106/106.
Review findings: the plan doc claimed no implementation existed, had the
domain dependency order wrong (kernel depends on protocol; device on
kernel + protocol + csv), never placed the three shared contracts, and
named a nonexistent new-driver-checklist.md. Its status now records the
implemented phases (and the deliberate pci-bus-first pilot), the target
shape carries the contract placements and the path-dependency-only
constraint on the kernel package's out-of-root abi export, and the
execution notes describe the post-pilot build for whichever session
runs the remaining waves. README's repo layout gains build-support/
and the packages-note; driver-model, threading, system-requirements,
and the two display plan docs stop citing root build.zig for recipe
facts that now live in build-support.
Each library domain (kernel, device, client, protocol, csv,
xkeyboard-config) now owns a build.zig + build.zig.zon that wires and
exports its modules, with a standalone `zig build test` per domain.
The kernel package also exports abi (source stays in system/abi.zig) so
every consumer names one module instance. The root build swaps its
createModule calls for b.dependency(...).module(...) — no binary moves;
the root is the pilot consumer (docs/build-packages-plan.md). Path
dependencies deduplicate by resolved location, so the diamond
(root -> device -> kernel, root -> kernel) yields a single instance of
each module. Boot-image file list unchanged.
Replaces L2's interim DMA pool (every buffer reachable by every claimed
device) with true per-grant confinement: a device reaches only buffers
whose capability was delegated to its driver.
Kernel:
- DmaRegionObject (handle kind 2): a delegation token naming a dma_alloc'd
region, passable across processes on the IPC cap slot like an endpoint
or shared-memory object. Frames stay owned by the allocating address
space (freed on dma_free/teardown as before); the token carries a `dead`
flag so a stale downstream handle can no longer bind a freed region.
- dma_alloc gains the dma_shareable flag: it returns a capability handle
in r8 and every region is tracked in a registry. A task's own regions
auto-bind into the devices it claims (its rings just work); foreign
buffers are bound explicitly.
- dma_bind / dma_unbind / handle_close syscalls (51-53). dma_bind maps a
held region (or shared-memory) capability into a claimed device's domain;
it is idempotent. handle_close reclaims a table slot (raised 16 -> 32).
- dma_free and task death unmap a region from every domain and invalidate
BEFORE its frames return to the allocator — the stale-IOTLB use-after-
free window, closed structurally.
Protocols (flag-day): block gains attach, usb-transfer gains dma_attach —
each carries a region capability on the cap slot. fat allocates its bounce
buffer shareable and attaches it; usb-storage allocates its transport
buffers shareable, attaches them to the controller, and forwards fat's
capability downstream; usb-xhci-bus binds and closes; virtio-gpu binds its
shared scanout surface. The physical addresses on the wire are unchanged
(identity IOVA), so no register-programming code moved.
Cross-process DMA (fat -> usb-storage -> xHC) now flows only through
delegated capabilities. iommu-usb-storage / iommu-usb-hid / iommu-fault
all green under per-grant enforcement; 104/104 overall (fail-open paths
unchanged).
With every consumer migrated (C2), nothing imports `runtime` or `system` any
longer. Removed both shim files and their build.zig module definitions, dropped
the `runtime` entry from `default_imports`, and rewrote the per-binary root shim
(library/kernel/root.zig) to import `start` (_start + panic) and `logging`
(std_options) directly instead of through `runtime`.
addUserBinary/addThreadedUserBinary/addUserBinaryImpl lose their `runtime_module`
parameter; the root module now pulls the two modules it needs out of
`default_imports` via a small findImport helper.
The runtime dumping ground is gone: the userspace library is library/kernel
(concern modules), library/device (driver/pci/usb/block/model/mmio/acpi data),
library/client (display, input service clients), and library/protocol (wire
contracts). Consumers @import concern modules by name.
Verified: zig build, zig build test, and QEMU (smoke, thread-spawn, thread-mutex,
logger, display-native, device-manager, usb-storage, input).
The one giant `runtime` module (with a `system.zig` that was itself a dumping
ground of unrelated syscalls) is split into directly-importable, flat concern
modules under library/kernel/:
system-call ipc memory process thread time logging file-system service start
(+ the device/service clients: device, device-manager, block, display, input)
system.zig is dissolved — its functions moved to their concern home (mmap ->
memory, spawn/kill/exit -> process, sleep/clock -> time, write/klog -> logging,
fs* -> file-system). `memory` merges heap+dma+shared-memory behind one flat API
(memory.allocator/dmaAlloc/sharedCreate/mmap), keeping heap's state and malloc
export single. The memory<->thread dependency cycle (heap needs Thread.Mutex,
thread needs mmap) is broken by having thread allocate its own stack via the raw
mmap syscall, so the module graph is a DAG.
This is the atomic step: all 42 internal cross-imports flip from relative to
module imports at once. `runtime.zig` and `system.zig` become thin re-export
SHIMS so the ~38 consumers keep compiling on `runtime.*` untouched; they migrate
to direct imports in C2, after which the shims are deleted (C5).
zig build + zig build test green; 14 QEMU cases pass (smoke, process,
process-kill, thread-spawn/join, logger, vfs, fat-mount, display-native,
usb-storage, virtio-gpu, device-manager, input, power-button).
First step of splitting the runtime dumping ground. Pure directory rename
(git mv library/runtime library/kernel) + the six build.zig path references
repointed. The module is still named "runtime" for now; the next commits split
it into concern modules (ipc, memory, process, time, logging, file-system, ...),
dissolve system.zig, and delete the runtime aggregator.
The library/kernel name follows the kernel32 model: it is the userspace library
that wraps the private kernel ABI, distinct from system/kernel/ (the kernel).
zig build green.
Daniel Samson