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Split the system contract into boot-handoff / abi / device-abi

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The `system` module (formerly `danos`) had become a grab-bag: it held the
loader<->kernel handoff *and* the kernel<->user ABI *and* the device wire types, in
one module three different audiences imported. Usage proved the seam — the
bootloader never touched the syscall/device ABI, and user space never touched the
boot handoff — so split it by audience, one module per contract:

  system/boot-handoff.zig       loader <-> kernel: BootInformation, Framebuffer,
                                MemoryMap, the VM layout + physicalToVirtual, kernel_abi
  system/abi.zig                kernel <-> user, core: SystemCall, mmap prot flags,
                                page_size, notify_badge_bit, ServiceId
  system/devices/device-abi.zig kernel <-> user, devices: DeviceDescriptor,
                                DeviceClass, ResourceDescriptor, ResourceKind, ...

device-abi is the devices sub-project's public interface, exposed as its own module
the way vfs exposes vfs-protocol — importable by user space, unlike the
kernel-internal device model it also feeds. That collapses a real duplication:
DeviceClass and ResourceKind were defined twice (device-model.zig and the contract,
kept "in sync by hand"); device-model now re-exports them from device-abi, so the
enum a driver matches on and the one the kernel classifies with are one type.

Each import now declares which contract it speaks: the bootloader imports only
boot-handoff; a driver only abi + device-abi (via the runtime); the kernel all
three. This also retires the `system` / `runtime.system` name overlap. page_size
lands in abi (it's part of the mmap contract user space aligns to); the bootloader
keeps its own local 4 KiB constant so it depends on nothing but the handoff.

All 21 importers rewired, docs updated to keep /system mapping to source. Build,
host tests, and the QEMU suite (36/36) all green.
This commit is contained in:
Daniel Samson
2026-07-10 18:08:51 +01:00
parent 47610e8ee2
commit be81394be3
37 changed files with 395 additions and 337 deletions
Download Patch File Download Diff File Expand all files Collapse all files
system/devices/acpi.zig
+13 -12
View File
@@ -15,7 +15,8 @@
//! the `Hal.mapMmio` callback the caller supplies (the architecture VMM's map primitive).
const std = @import("std");
const system = @import("system");
const boot_handoff = @import("boot-handoff");
const abi = @import("abi");
const parameters = @import("parameters");
const device_model = @import("device-model.zig");
const aml = @import("aml/aml.zig");
@@ -147,7 +148,7 @@ var aml_block_count: usize = 0;
fn addAmlBlock(sdt_physical: u64) void {
if (aml_block_count >= aml_block_physical.len or sdt_physical == 0) return;
const h: *const SystemDescriptorTableHeader = @ptrFromInt(system.physicalToVirtual(sdt_physical));
const h: *const SystemDescriptorTableHeader = @ptrFromInt(boot_handoff.physicalToVirtual(sdt_physical));
if (h.length <= @sizeOf(SystemDescriptorTableHeader)) return;
aml_block_physical[aml_block_count] = sdt_physical + @sizeOf(SystemDescriptorTableHeader);
aml_block_len[aml_block_count] = h.length - @sizeOf(SystemDescriptorTableHeader);
@@ -376,14 +377,14 @@ pub fn discover(rsdp_physical: u64, device_tree: *DeviceTree, hal: Hal) !void {
dsdt_physical = 0;
aml_block_count = 0;
const rsdp: *const RootSystemDescriptionPointer = @ptrFromInt(system.physicalToVirtual(rsdp_physical));
const rsdp: *const RootSystemDescriptionPointer = @ptrFromInt(boot_handoff.physicalToVirtual(rsdp_physical));
if (!std.mem.eql(u8, &rsdp.signature, "RSD PTR ")) return error.BadRsdpSignature;
// Revision 0 checksums only the first 20 bytes (the v1.0 RSDP).
if (!checksumOk(@ptrFromInt(system.physicalToVirtual(rsdp_physical)), 20)) return error.BadRsdpChecksum;
if (!checksumOk(@ptrFromInt(boot_handoff.physicalToVirtual(rsdp_physical)), 20)) return error.BadRsdpChecksum;
if (rsdp.revision >= 2) {
const xsdp: *const ExtendedSystemDescriptorPointer = @ptrFromInt(system.physicalToVirtual(rsdp_physical));
if (!checksumOk(@ptrFromInt(system.physicalToVirtual(rsdp_physical)), xsdp.length)) return error.BadXsdpChecksum;
const xsdp: *const ExtendedSystemDescriptorPointer = @ptrFromInt(boot_handoff.physicalToVirtual(rsdp_physical));
if (!checksumOk(@ptrFromInt(boot_handoff.physicalToVirtual(rsdp_physical)), xsdp.length)) return error.BadXsdpChecksum;
try walkRoot(u64, xsdp.extended_system_descriptor_table_address, device_tree, hal);
} else {
try walkRoot(u32, rsdp.root_system_description_table_address, device_tree, hal);
@@ -393,7 +394,7 @@ pub fn discover(rsdp_physical: u64, device_tree: *DeviceTree, hal: Hal) !void {
// read the sleep types from it.
var blocks: [aml_block_physical.len][]const u8 = undefined;
for (0..aml_block_count) |i| {
blocks[i] = @as([*]const u8, @ptrFromInt(system.physicalToVirtual(aml_block_physical[i])))[0..aml_block_len[i]];
blocks[i] = @as([*]const u8, @ptrFromInt(boot_handoff.physicalToVirtual(aml_block_physical[i])))[0..aml_block_len[i]];
}
const active = blocks[0..aml_block_count];
if (aml.parse(device_tree.allocator, active)) |pr| {
@@ -412,11 +413,11 @@ pub fn discover(rsdp_physical: u64, device_tree: *DeviceTree, hal: Hal) !void {
/// Walk the RSDT (Entry = u32) or XSDT (Entry = u64): validate it, then dispatch
/// each SDT it points at. A bad individual table is skipped, not fatal.
fn walkRoot(comptime Entry: type, root_physical: u64, device_tree: *DeviceTree, hal: Hal) !void {
const header: *const SystemDescriptorTableHeader = @ptrFromInt(system.physicalToVirtual(root_physical));
if (!checksumOk(@ptrFromInt(system.physicalToVirtual(root_physical)), header.length)) return error.BadRootChecksum;
const header: *const SystemDescriptorTableHeader = @ptrFromInt(boot_handoff.physicalToVirtual(root_physical));
if (!checksumOk(@ptrFromInt(boot_handoff.physicalToVirtual(root_physical)), header.length)) return error.BadRootChecksum;
const count = (header.length - @sizeOf(SystemDescriptorTableHeader)) / @sizeOf(Entry);
const base: [*]const u8 = @ptrFromInt(system.physicalToVirtual(root_physical));
const base: [*]const u8 = @ptrFromInt(boot_handoff.physicalToVirtual(root_physical));
const entries: [*]align(1) const Entry = @ptrCast(base + @sizeOf(SystemDescriptorTableHeader));
for (entries[0..count]) |ent| {
@@ -427,7 +428,7 @@ fn walkRoot(comptime Entry: type, root_physical: u64, device_tree: *DeviceTree,
/// Dispatch a single SDT on its signature.
fn handleTable(device_tree: *DeviceTree, hal: Hal, sdt_physical: u64) !void {
const header: *const SystemDescriptorTableHeader = @ptrFromInt(system.physicalToVirtual(sdt_physical));
const header: *const SystemDescriptorTableHeader = @ptrFromInt(boot_handoff.physicalToVirtual(sdt_physical));
const sig = header.signature;
if (std.mem.eql(u8, &sig, &APIC)) {
try parseMadt(device_tree, header);
@@ -1120,7 +1121,7 @@ fn pciConfigurationPtr(alloc: McfgAllocation, hal: Hal, bus: u8, device: u8, fun
(@as(u64, function) << 12);
// Map the configuration page (writable, for BAR sizing) and use the virtual
// address the HAL hands back.
return @ptrFromInt(hal.mapMmio(physical, system.page_size, true));
return @ptrFromInt(hal.mapMmio(physical, abi.page_size, true));
}
/// Read a little-endian integer at `off` from a (possibly unaligned) byte pointer.