f38eb8a7fd
L4 was listed as "free -- H2 built all of this" and never actually tested,
which is a claim rather than a result. Tested now, and it holds:
ldlsd running ping 2/2; holds index 7 and DMA slots 3 and 4
killed interface DOWN, device released, bus mastering
cleared, DMA reclaimed -- back to vgpud's 3 blocks
ping fails honestly: sendto: -5
a second ldlsd ping 3/3, and the arena hands back the same addresses
pciuser_release_all() and netuser_release_all() sit beside each other in
exit() for the same reason, and that they apply unchanged to a foreign driver
is the whole point of having built them against our own.
With that, every milestone on ldls.md is done, so it leaves docs/plan/ for
docs/architecture/ -- the rule docs/plan/README.md states and the one that
keeps the two directories meaning different things. The new document describes
what is, not what was planned: the five rules, the four pieces, what it costs
(polling, no stack protector, locks that are no-ops), that it can be killed,
and a "what it does not do" that leads with one driver, one kernel version,
tried once.
Sixteen source files pointed at docs/plan/ldls.md and would have been dangling
the moment it moved. All repointed, and the milestone references -- which the
architecture doc deliberately does not have -- rewritten to name sections
instead, so a reader lands somewhere real.
The register row closes with it. hybrid.md freed a slot, ldls.md took it, and
it is now free again.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VQ7Qx8E1q1M1bbCq8QLHS2
146 lines
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146 lines
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# What happens next
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Everything in this directory is **unbuilt**. When a piece of it is finished it
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leaves — deleted from here, rewritten as a description in
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[../architecture/](../architecture/). See [the rule](../README.md#the-rule-that-keeps-this-from-rotting).
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> ## Read [1.0.md](1.0.md) first.
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>
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> It draws a finish line and puts most of the work below on the far side of it.
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> **Anything not named there is not being worked on**, and the documents in this
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> directory describe more than 1.0 contains.
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>
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> It also holds **[the register of unfinished work](1.0.md#the-freeze-and-the-register-of-unfinished-work)**,
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> which is the one place anything half-built is listed. No new capability starts
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> until that register is empty, and a row leaves it only by being finished or by
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> being deleted from the tree.
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---
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## The three current decisions
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Taken together, because they turn out to need the same foundation.
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|---|---|
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| **[wayland.md](wayland.md)** | The GUI stack becomes Wayland. SchWM and SchDE are **deleted** — actually gone from the tree, not marked; Schcom survives and changes its wire format. |
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| ~~**hybrid.md**~~ | **Built.** All four mechanisms exist, the GPU driver runs outside the kernel, it survives being killed, and the display mode can be changed from a process. H4 (USB) was *withdrawn* rather than left open — USB is the bus peripherals arrive on, not a peripheral. |
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| ~~init.md~~ | **Built.** PID 1 is now a role the kernel refills; the description moved to [../architecture/init.md](../architecture/init.md). |
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And the one they all wait on:
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| **[foundations.md](foundations.md)** | Descriptor passing, shared memory, sockets in the filesystem. The critical path. **Item 1 is built** — `sendmsg`/`recvmsg` with `SCM_RIGHTS`. |
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And the one that says which parts of the above are actually being worked on:
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| **[1.0.md](1.0.md)** | The finish line. Four gates, and everything else explicitly deferred. |
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And the one the hybrid mechanisms were built for:
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| ~~ldls.md~~ | **Built.** The Linux Driver Layer for SchOS: someone else's drivers, in a process, reached through `/dev/pci`. `ping` works over `8139too`. The description moved to [../architecture/ldls.md](../architecture/ldls.md). |
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And one that is a tool rather than a capability:
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| **[debugger.md](debugger.md)** | A debugger for this kernel — one that observes rather than halts, and answers in this kernel's own vocabulary. **Built**, except the network transport: symbols, a log that outlives the kernel, `/dev/dbg`, the `whose` ownership query and hardware watchpoints are all described in [../architecture/debugging.md](../architecture/debugging.md). |
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Two longer-horizon documents sit behind these: [schapi.md](schapi.md), the API
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layering and the compatibility promise, and [roadmap.md](roadmap.md), which holds
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everything still open that is not one of the three above.
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---
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## The order
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Set by [1.0.md](1.0.md), which is the authority. In short:
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### 0. Fix what is already wrong — **first**
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Not a document of its own; it is Gate 0 of [1.0.md](1.0.md), assembled from the
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*What it does not do* sections in [../architecture/](../architecture/).
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**Before any new capability**, and the reason is the one that put
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`netdev_selftest()` before the TCP/IP stack: a compositor built on a kernel with
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an unexplained hang and a socket layer that reports success for things it did not
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do will fail in ways indistinguishable from its own bugs.
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### 1. `foundations.md` — the critical path
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Both the Wayland work and the hybrid work stop here. Descriptor passing and
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shared memory are the substrate for handing a buffer to a compositor *and* for
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handing a device to a driver process. **Doing it once for both is the entire
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reason these are one plan rather than three.**
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### 2. `init.md` — before the desktop, not after — **done**
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A compositor being brought up for the first time crashes constantly, and
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something that restarts it and says why is worth far more during that work than
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at the end of it. Built; see [../architecture/init.md](../architecture/init.md).
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### 3. `hybrid.md` — **moved up, and the reason is worth recording**
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This document used to put the hybrid work *after 1.0*, deliberately last, on this
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argument:
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> designing a userspace driver interface with no driver consuming it produces an
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> interface that is wrong in ways nobody can see
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The argument was sound and the conclusion drawn from it was wrong. What forced
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the change was the driver situation: SchOS cannot write a driver for every device
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that exists, no project can, and the only route to the hardware support an
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established OS has is a compatibility layer with the foreign drivers kept
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*outside* the kernel. That layer is this plan's mechanisms. It is not optional and
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it is not late work.
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The original argument still holds, and it is answered rather than ignored:
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**SchOS's own drivers are the consumers.** `vgpud` is a real driver, with real
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requirements, and building the interface against it is what keeps it a general
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mechanism rather than a hole shaped like something foreign. The compositor is
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still a demanding consumer — it is no longer the *only* one available.
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Four mechanisms, all built. One eviction done, the second withdrawn with its
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reasons recorded, and the foreign driver host they were for is
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[../architecture/ldls.md](../architecture/ldls.md) — built, and carrying
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packets.
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### 4. `wayland.md` — with the GPU driver either side of the seam
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W1–W3 and a terminal. W4 and W5 are post-1.0. Item 1 of `foundations.md` —
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descriptor passing — was the thing it could not start without, and it now
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exists.
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---
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## In one sentence
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> Fix what is broken, build the descriptor-passing and shared-memory substrate,
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> make init survivable, move the drivers out through an interface SchOS's own
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> drivers have to live with first — and put a terminal on the screen.
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---
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## What this plan does not address
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Stated here so it is not mistaken for covered:
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- **No IOMMU**, so the hybrid work isolates against bugs and not against a
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hostile driver.
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- **No page cache**, so `foundations.md` delivers a `memfd` and not a general
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answer to shared file mappings. The general answer is still owed.
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- **No garbage collector for descriptors in flight**, so an `AF_UNIX` socket
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passed over itself and never received leaks. Bounded at thirty-two sockets, and
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nothing on this plan does it.
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- **No dynamic linking**, so no Mesa, no accelerated clients, and no third party
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shipping a `.so` for anything.
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- **A new compatibility surface** between PID 1 and PID 2, created by a plan
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whose own [schapi.md](schapi.md) §3 spends a section warning about those.
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- **The three open networking items** — `getsockname`, routing, and
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interrupt-driven receive — are untouched by any of this and still open. They
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are in [roadmap.md](roadmap.md).
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