Daniel Samson
8754d4e46a
The source layout now mirrors the runtime filesystem hierarchy
(docs/danos-file-system-hierarchy-FSH.md): what lives under system/ in the
source is what a running danos represents under /system. Each service and
driver is a sub-project directory that is its own Zig module — cross-project
references go by module name, never by a path into another project's files.
Moves (all git mv, history preserved):
- src/ -> system/ (danos internals; the self-representation)
root.zig -> danos.zig (the kernel<->user contract module)
kernel/arch/ -> kernel/architecture/ (arch -> architecture)
device/ -> devices/ (what /system/devices reflects)
boot/ -> /boot (the loaders, top level)
- sbin/ -> split by role:
init, vfs -> system/services/<name>/<name>.zig
hpetd, busd -> system/drivers/<name>/<name>.zig
vfs-test -> system/services/vfs/vfs-test.zig (inside the vfs project)
- lib/ -> library/runtime/ (room for other libraries beside runtime)
The VFS wire protocol becomes its own module, system/services/vfs/protocol.zig
("vfs-protocol"): the vfs sub-project exposes its interface, and the runtime's
file layer imports it by name. First instance of the "protocol module" pattern
(docs/driver-model.md); usb/block will expose theirs the same way.
Also: fix a naming-standard violation in the protocol — Op -> Operation (and
req -> request, _pad -> _padding). Docs updated: /system/services added to the
FHS doc, a repository-layout section added to the docs index, and stale source
paths swept across comments and docs.
Runtime boot paths are unchanged (the bootloader still loads /sbin/init);
aligning the runtime filesystem to the FHS is a separate follow-up. Suite 35/35
plus host tests green.
33 lines
1.2 KiB
Zig
33 lines
1.2 KiB
Zig
//! The user-space process entry shim. Every user binary roots `_start` here (via
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//! `entry = _start` in build.zig) and forces this file to be analysed with
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//! `comptime { _ = &runtime.start._start; }`, so the whole runtime is linked in.
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const std = @import("std");
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const system = @import("system.zig");
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/// The kernel enters at `_start` with rsp 16-aligned, but a SystemV function expects
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/// rsp ≡ 8 (mod 16) on entry (as if reached by `call`). The `call` below pushes
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/// the 8-byte return address, satisfying the ABI before any Zig frame runs; the
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/// `ud2` is a safety net if `rt_start` ever returns.
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pub export fn _start() callconv(.naked) noreturn {
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asm volatile (
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\\call rt_start
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\\ud2
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);
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}
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/// The first Zig frame. The heap is lazy (first alloc grows it), so there is no
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/// runtime init to order here — just hand control to the program's `main`.
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export fn rt_start() callconv(.c) noreturn {
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const root = @import("root"); // the user binary's root source file
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root.main();
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system.exit(0);
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}
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/// No runtime to unwind into — report a panic as a nonzero exit code.
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pub const panic = std.debug.FullPanic(struct {
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fn panic(_: []const u8, _: ?usize) noreturn {
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system.exit(127);
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}
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}.panic);
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