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docs: architecture describes what is built now

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kernel (threads, demand paging, TLB shootdowns, dynamic linking, RAM direct map), syscalls, filesystem (/proc, /sys,
/dev), terminals (12, VT handshake, ptys), networking (r8169 through LDLS), LDLS (module sets; Linux code may ship),
devices (what stays in the kernel; hybrid.md's lasting content), boot (the loader's placement of the kernel),
graphics (fbdev, GMMOS, QR 1-40), audio (ALSA over OSS), debugging, usb. New: packages.md (the apk root) and
desktop.md (Xorg on the framebuffer).

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EVRhxi9zpdW2uDUN4FVcao
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Nexoniarz 2026-10-26 07:57:25 +01:00
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18
docs/architecture/debugging.md
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@ -179,6 +179,10 @@ part of the boot is blank for the part that is hardest to debug any other way.
---
A panic is not the end of the log. GMMOS ([graphics.md](graphics.md)) keeps running
under the report, can show this log on screen or as QR codes a phone can read, and
has a small terminal for looking around a machine whose kernel is dead.
## Asking a question
`/dev/dbg` is a conversation: write a line, read the answer.
@ -493,10 +497,16 @@ something that reports nonsense.
- **One conversation at a time.** The answer buffer is global, so two programs
asking at once get one answer each in some order — never half of the other's,
but not two independent sessions either.
- **No userspace symbolization.** The kernel names kernel symbols. A fault in a
process still reports a bare address, and resolving it is a host-side job.
- **The stack walk stops where the frame pointer stops.** `getcallerpcs()` walks
`rbp` chains, so a trap frame in the middle of a chain ends the walk.
- **No userspace symbolization.** The kernel names kernel symbols. A process
killed by a fault is told which *file and offset* it died in (from
`/proc/<pid>/maps`' records), which is enough to resolve with the file's own
symbols on the host; a bare address is all there is for anonymous memory.
- **The stack walk stops where the frame pointer stops, and it will not follow a
bad one.** `getstackpcs()` walks `rbp` chains, and each link must go up the same
stack by less than `KSTACKSIZE`: a chain can end at the syscall entry with a *user*
`rbp` that a program uses as an ordinary register (`-1024` in one game), and
dereferencing that under the syscall tracer once panicked the kernel inside
`acquire()`. A trap frame in the middle of a chain ends the walk.
- **`sysrq g` costs you log history.** Its output goes through `cprintf`, so
sixteen kilobytes of views push the same amount out of a 128 KB ring.
- **No tracing.** No static tracepoints, no event ring, no counters. "What