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M11–M12: IRQ-as-IPC and bus drivers; expand names tree-wide

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Two driver-model milestones plus a tree-wide naming pass. Suite 35/35
(QEMU) + host tests green.

M11 — IRQ-as-IPC. A ring-3 driver now sleeps until its device interrupts
it. New src/kernel/irq.zig: per-GSI endpoint bindings, comptime per-vector
trampolines, dispatch = mask GSI -> LAPIC EOI -> notifyLocked, all under one
lock region. irq_bind/irq_ack syscalls, gated by the device claim like
mmio_map. interruptDispatch no longer EOIs — each handler owns its EOI,
because a level line must be masked before it is acknowledged (irq_ack is
the unmask). Bindings are keyed on the owning task and released on exit
(a shared endpoint's siblings survive). hpetd rewritten interrupt-driven.
Tests: hpet (rewritten, reads back the I/O APIC routing) and irqfree.

M12 — bus drivers. DeviceDesc gains a parent, making the device table a
tree. dev_register (device_register) lets a process publish children below
a device it claimed; the kernel enforces resource containment (a child's
resources must nest in its parent's), so a descriptor can't fabricate a
window over kernel RAM. Descriptor copied in via copyFromUser (physmap
walk — an unmapped user pointer fails the call instead of faulting the
kernel). Per-parent child cap bounds table exhaustion. sbin/busd.zig is a
worked bus driver. Test: bus.

Naming — per docs/coding-standards.md: non-acronym abbreviations spelled
out (message, descriptor, device_service, scheduler, runtime, physical,
interpreter, ...); acronyms kept (IPC, MMIO, DMA, HCD, ...); files are
kebab-case (ipc-synchronous.zig, device-service.zig, vfs-protocol.zig, ...).
Exceptions: POSIX/C ABI names and Zig idioms (init/len/ptr) kept. Module
collisions resolved by specific naming (config -> parameters, device.zig
alias -> device_model). AML op/Op disambiguated: op = opcode, Op =
operation; per-opcode parse handlers renamed opX -> parseX.

New driver docs: drivers.md, driver-model.md (bus/class/HCD shapes + the
proposed M13–M16 ABI), coding-standards.md.
This commit is contained in:
Daniel Samson
2026-07-10 11:39:56 +01:00
parent 83881641ca
commit 15b70856c9
63 changed files with 4722 additions and 2690 deletions
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lib/start.zig
+5 -5
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@@ -1,11 +1,11 @@
//! The user-space process entry shim. Every user binary roots `_start` here (via
//! `entry = _start` in build.zig) and forces this file to be analysed with
//! `comptime { _ = &rt.start._start; }`, so the whole runtime is linked in.
//! `comptime { _ = &runtime.start._start; }`, so the whole runtime is linked in.
const std = @import("std");
const sys = @import("sys.zig");
const system = @import("system.zig");
/// The kernel enters at `_start` with rsp 16-aligned, but a SysV function expects
/// The kernel enters at `_start` with rsp 16-aligned, but a SystemV function expects
/// rsp ≡ 8 (mod 16) on entry (as if reached by `call`). The `call` below pushes
/// the 8-byte return address, satisfying the ABI before any Zig frame runs; the
/// `ud2` is a safety net if `rt_start` ever returns.
@@ -21,12 +21,12 @@ pub export fn _start() callconv(.naked) noreturn {
export fn rt_start() callconv(.c) noreturn {
const root = @import("root"); // the user binary's root source file
root.main();
sys.exit(0);
system.exit(0);
}
/// No runtime to unwind into — report a panic as a nonzero exit code.
pub const panic = std.debug.FullPanic(struct {
fn panic(_: []const u8, _: ?usize) noreturn {
sys.exit(127);
system.exit(127);
}
}.panic);