kernel: flatten the device/discovery code, merge power into acpi, rename fdt
Follow-up cleanup of the just-moved kernel device code: - power.zig -> acpi.zig. Its reboot() is built entirely on the FADT reset register (acpi.power_information) plus the legacy 0xCF9/8042 fallbacks — it is ACPI reboot, so it becomes acpi.reboot (the "P" in ACPI). platform.reboot still delegates; soft-off/S5 stays the ring-3 acpi service's job as before. - device-tree.zig -> fdt.zig. It is a discovery *backend* (the ARM/FDT parser, a sibling of acpi.zig), not part of the model — renaming it to its actual subject kills the confusing device-tree / device-model DeviceTree name clash and makes acpi.zig + fdt.zig read as the two parallel backends. - Flatten: device-model.zig, acpi.zig, fdt.zig, platform.zig move out of the system/kernel/devices/ subdir up into system/kernel/, joining devices-broker.zig (already flat). The kernel dir is a flat pile by convention (only architecture/ is a subdir), so the subdir — and its poor "devices" name — is gone. Pure restructure; "platform" module name unchanged, all cross-file deps are relative siblings that moved together. zig build + test green; smoke, discovery, acpi-parse, acpi-ps2, acpi-report, power-button, orderly-shutdown, reboot pass.
This commit is contained in:
Daniel Samson
parent
3a155cdc7d
commit
11f567ee20
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@ -278,7 +278,7 @@ pub fn build(b: *std.Build) void {
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});
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// The devices sub-project's public interface (the flat wire types), exposed as
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// its own module like vfs-protocol — importable by user space, unlike the
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// kernel-internal device model it also feeds (system/kernel/devices/device-model.zig).
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// kernel-internal device model it also feeds (system/kernel/device-model.zig).
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const device_abi_module = b.addModule("device-abi", .{
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.root_source_file = b.path("library/device/model/device-abi.zig"),
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});
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@ -351,9 +351,9 @@ pub fn build(b: *std.Build) void {
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// "platform" and asks it to enumerate hardware into a backend-neutral device
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// tree, never naming ACPI (or, later, device-tree) — the same discipline the
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// architecture module applies to CPU code. The backend is selected at runtime from
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// the boot handoff (see system/kernel/devices/platform.zig).
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// the boot handoff (see system/kernel/platform.zig).
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const platform_module = b.addModule("platform", .{
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.root_source_file = b.path("system/kernel/devices/platform.zig"),
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.root_source_file = b.path("system/kernel/platform.zig"),
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.imports = &.{
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.{ .name = "boot-handoff", .module = boot_handoff_module }, // BootInformation (carries the ACPI RSDP), physicalToVirtual
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.{ .name = "abi", .module = abi_module }, // acpi.zig works in page_size units
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@ -238,9 +238,9 @@ system/ → /system danos's own internals (the self-representation)
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parameters.zig initial-ramdisk.zig shared contracts
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kernel/ IPC, memory, scheduling, the VFS root, the private syscall dispatch
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architecture/x86_64/ the `architecture` module (never named by generic code)
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devices/ the kernel-internal device model + firmware discovery
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(device-model, platform, acpi, device-tree, power) — the
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implementation of the device tree /system/devices reflects
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devices-broker.zig the syscall-facing device table
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platform.zig acpi.zig fdt.zig device-model.zig firmware discovery + the kernel's
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device model — the implementation of what /system/devices reflects
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drivers/ pci-bus/ ps2-bus/ usb-xhci-bus/ one sub-project per driver → /system/drivers
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services/ init/ fat/ device-manager/ system servers → /system/services (fat/ holds
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fat.zig, engine.zig, on-disk.zig)
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@ -300,7 +300,7 @@ exception in [coding-standards.md](coding-standards.md) applies to that seam.
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| VFS root: mount table + kernel-served nodes (`fs_resolve`/`fs_node`); wire protocol in `library/protocol/vfs/vfs-protocol.zig` | `system/kernel/vfs.zig` |
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| Device tree + claim capability + `device_register` containment | `system/kernel/devices-broker.zig` |
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| IRQ-as-IPC: routing a device interrupt to a driver's endpoint | `system/kernel/irq.zig` |
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| Hardware discovery (ACPI/device tree) behind one neutral device model | `system/kernel/devices/` |
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| Hardware discovery (ACPI/device tree) behind one neutral device model | `system/kernel/platform.zig` |
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| Framebuffer text console (mirrors to serial) | `system/kernel/console.zig` |
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| In-kernel test cases | `system/kernel/tests.zig` |
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| Arch-specific kernel code (`halt`, GDT/IDT/TSS, exception + interrupt stubs, page tables, APIC/IO-APIC/timer, serial, linker script) | `system/kernel/architecture/x86_64/` |
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@ -19,10 +19,10 @@ UEFI configuration table
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BootInformation.acpi_rsdp (u64, in the loader↔kernel handoff) system/boot-handoff.zig
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│ the kernel forwards the whole BootInformation
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▼
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platform.discover(boot_information, …) system/kernel/devices/platform.zig
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platform.discover(boot_information, …) system/kernel/platform.zig
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│ reads boot_information.acpi_rsdp, hands it to the ACPI backend
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▼
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acpi.discover(rsdp_phys, …) system/kernel/devices/acpi.zig
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acpi.discover(rsdp_phys, …) system/kernel/acpi.zig
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│ dereferences the RSDP, reads the pointer it contains
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▼
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RSDP ──(a field in the struct)──► RSDT / XSDT ──► SDTs (MADT, MCFG, FADT, HPET, DSDT…)
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@ -135,7 +135,7 @@ Within those spelling rules, follow Zig's own conventions:
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`notify_badge_bit`.
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**File names are `kebab-case`.** A file named for a multi-word thing hyphenates it:
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`device-tree.zig`, `ipc-synchronous.zig`, `vfs-protocol.zig`, `devices-broker.zig`. A
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`device-model.zig`, `ipc-synchronous.zig`, `vfs-protocol.zig`, `devices-broker.zig`. A
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single word or acronym needs no hyphen: `scheduler.zig`, `paging.zig`, `apic.zig`,
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`idt.zig`. (The module *alias* a file is imported under still follows the code
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conventions above — `snake_case` — because it's an identifier, not a filename.)
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@ -92,9 +92,9 @@ fails rather than hangs.
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`acpi-tables` node ([discovery.md](discovery.md)) already put the PM1 control
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ports in the acpi service's hands, so writing S5 from ring 3 is something it
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could physically already do; formalizing it as a protocol operation added a
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contract, not authority. The kernel's `system/kernel/devices/power.zig` keeps only
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**reboot** (the FADT reset register plus the legacy fallbacks, which need no AML);
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it has no poweroff path at all — S5 is not a kernel operation.
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contract, not authority. The kernel keeps only **reboot** (`acpi.reboot` in
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`system/kernel/acpi.zig` — the FADT reset register plus the legacy fallbacks, which
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need no AML); it has no poweroff path at all — S5 is not a kernel operation.
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## Verifying it
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@ -115,7 +115,7 @@ hypervisor configured for UEFI firmware and an xHCI USB controller.
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(`efi.zig:790`, `boot-handoff.zig:149`)
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- **Required ACPI tables:** MADT (interrupt topology), MCFG (PCIe ECAM base),
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FADT (power / PM timer). Optionally consumed: HPET, DMAR, SPCR.
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(`system/kernel/devices/acpi.zig:3`)
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(`system/kernel/acpi.zig:3`)
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- The loader reads `/system/kernel` off the FAT boot volume, then loads user
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space: a prebuilt `boot\system.img` capsule
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([system-image.md](system-image.md)) when present, otherwise it walks
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@ -221,7 +221,7 @@ named for reporting only; internal SATA / NVMe / IDE disks have no driver.
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first VT-d DRHD unit and its capabilities are exposed via `PlatformInformation`
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(`iommu_present`, `iommu_base`, `iommu_version`). No DMA-remapping tables are
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programmed and no translation is enforced. An IOMMU is therefore **not required**
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and does not currently constrain devices. (`system/kernel/devices/acpi.zig:96`)
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and does not currently constrain devices. (`system/kernel/acpi.zig:96`)
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## What is explicitly NOT supported
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@ -6,7 +6,7 @@
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//! by name, and neither reaches into the other's files.
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//!
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//! It is also the **single source of truth** for `DeviceClass` and `ResourceKind`:
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//! the kernel's rich, pointer-based device tree (system/kernel/devices/device-model.zig,
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//! the kernel's rich, pointer-based device tree (system/kernel/device-model.zig,
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//! which user space must never import) re-exports these, so the enum that a driver
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//! matches on and the enum the kernel classifies with are the *same* type — no
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//! hand-kept "mirror in order" to drift. The core kernel↔user ABI is [[abi]]; the
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@ -60,7 +60,7 @@ pub const PowerInformation = struct {
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reset_supported: bool = false,
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};
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/// Filled in by `discover`; the power service reads it to reboot/shutdown.
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/// Filled in by `discover`; `reboot` (below) reads it to restart the machine.
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pub var power_information: PowerInformation = .{};
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/// A legacy ISA IRQ remapped to a different global system interrupt (GSI), from a
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@ -839,3 +839,50 @@ fn rd(comptime T: type, bytes: [*]align(1) const u8, off: usize) T {
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const p: *align(1) const T = @ptrCast(bytes + off);
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return p.*;
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}
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// --- machine reboot -------------------------------------------------------------
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// Restart via the FADT reset register (from `power_information` above), with legacy
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// fallbacks, driven through the injected `Hal`. Soft-off (ACPI S5) and suspend (S3)
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// are NOT here: they need the AML sleep-state (`_Sx`) values, which the kernel no
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// longer parses — the ring-3 acpi service owns power management (it re-parses the
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// blobs and writes the PM1 control register itself). Reboot stays in the kernel
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// because it needs no AML — only the FADT reset register and the well-known legacy
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// fallbacks — so it survives as a last-resort restart. See docs/power.md.
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/// Restart the machine. Tries the ACPI reset register first, then the two legacy
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/// fallbacks. Returns only if every method failed (very unlikely).
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pub fn reboot(hal: device_model.Hal) void {
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const pi = power_information;
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// 1. The FADT reset register, when the firmware advertises support.
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if (pi.reset_supported and pi.reset.present()) {
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writeResetRegister(hal, pi.reset, pi.reset_value);
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rebootDelay();
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}
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// 2. The PCI reset-control register at port 0xCF9 (RST_CPU | SYSTEM_RST).
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hal.pioWrite(1, 0xCF9, 0x0E);
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hal.pioWrite(1, 0xCF9, 0x06);
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rebootDelay();
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// 3. Pulse the 8042 keyboard controller's reset line.
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hal.pioWrite(1, 0x64, 0xFE);
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rebootDelay();
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}
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fn writeResetRegister(hal: device_model.Hal, register: RegisterAccess, value: u32) void {
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if (register.mmio) {
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const p: *align(1) volatile u32 = @ptrFromInt(hal.mapMmio(register.address, 4, true));
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p.* = value;
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} else {
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hal.pioWrite(register.width, @intCast(register.address), value);
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}
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}
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/// A short busy-wait so a reset takes effect before we fall through to the next
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/// method. The empty asm is an architecture-neutral barrier that keeps the loop
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/// from being optimised away.
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fn rebootDelay() void {
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var i: usize = 0;
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while (i < 50_000_000) : (i += 1) {
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asm volatile ("" ::: .{ .memory = true });
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}
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}
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@ -1,51 +0,0 @@
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//! Machine reboot: restart via the FADT reset register, with legacy fallbacks.
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//!
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//! Built on the register map `acpi` extracted from the FADT, driven through the
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//! injected `Hal` (port I/O and MMIO). Soft-off (ACPI S5) and suspend (S3) are
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//! **not** here: they need the AML sleep-state (`_Sx`) values, which the kernel no
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//! longer parses — the ring-3 acpi service owns power management (it re-parses the
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//! blobs and writes the PM1 control register itself). See docs/power.md. Reboot
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//! stays in the kernel because it needs no AML — only the FADT reset register and
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//! the well-known legacy fallbacks — so it survives as a last-resort restart.
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const acpi = @import("acpi.zig");
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const device_model = @import("device-model.zig");
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const Hal = device_model.Hal;
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/// Restart the machine. Tries the ACPI reset register first, then the two legacy
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/// fallbacks. Returns only if every method failed (very unlikely).
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pub fn reboot(hal: Hal) void {
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const pi = acpi.power_information;
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// 1. The FADT reset register, when the firmware advertises support.
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if (pi.reset_supported and pi.reset.present()) {
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writeRegister(hal, pi.reset, pi.reset_value);
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delay();
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}
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// 2. The PCI reset-control register at port 0xCF9 (RST_CPU | SYSTEM_RST).
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hal.pioWrite(1, 0xCF9, 0x0E);
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hal.pioWrite(1, 0xCF9, 0x06);
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delay();
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// 3. Pulse the 8042 keyboard controller's reset line.
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hal.pioWrite(1, 0x64, 0xFE);
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delay();
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}
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fn writeRegister(hal: Hal, register: acpi.RegisterAccess, value: u32) void {
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if (register.mmio) {
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const p: *align(1) volatile u32 = @ptrFromInt(hal.mapMmio(register.address, 4, true));
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p.* = value;
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} else {
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hal.pioWrite(register.width, @intCast(register.address), value);
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}
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}
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/// A short busy-wait so a reset takes effect before we fall through to the next
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/// method. The empty asm is an architecture-neutral barrier that keeps the loop
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/// from being optimised away.
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fn delay() void {
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var i: usize = 0;
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while (i < 50_000_000) : (i += 1) {
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asm volatile ("" ::: .{ .memory = true });
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}
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}
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@ -12,8 +12,7 @@ const std = @import("std");
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const boot_handoff = @import("boot-handoff");
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const device_model = @import("device-model.zig");
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const acpi = @import("acpi.zig");
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const power = @import("power.zig");
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const devicetree = @import("device-tree.zig");
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const fdt = @import("fdt.zig");
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pub const DeviceTree = device_model.DeviceTree;
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pub const Device = device_model.Device;
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@ -74,7 +73,7 @@ pub fn discover(
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// No ACPI RSDP. A device-tree boot would parse its blob here; today that
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// path is a stub, so this reports the machine described itself no way we
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// understand yet.
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try devicetree.discover(&device_tree);
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try fdt.discover(&device_tree);
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}
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return device_tree;
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@ -84,5 +83,5 @@ pub fn discover(
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/// worked (extremely unlikely). Backend-agnostic entry the kernel calls. Soft-off
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/// (S5) is not a kernel operation — the ring-3 acpi service owns it (docs/power.md).
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pub fn reboot(hal: Hal) void {
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power.reboot(hal);
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acpi.reboot(hal);
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}
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