219 lines
5.6 KiB
HTML
219 lines
5.6 KiB
HTML
<!doctype html>
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<html lang="en">
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<head>
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<meta charset="utf-8">
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<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
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<title>reveal.js</title>
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<link rel="stylesheet" href="dist/reset.css">
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<link rel="stylesheet" href="dist/reveal.css">
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<link rel="stylesheet" href="dist/theme/sky.css">
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<!-- Theme used for syntax highlighted code -->
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<link rel="stylesheet" href="plugin/highlight/zenburn.css">
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</head>
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<body>
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<div class="reveal">
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<div class="slides">
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<section>
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<h1>Xous</h1>
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<h2>Embedded Multiprocess Microkernel</h2>
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<h3>17 April 2024, Sean Cross</h3>
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</section>
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<section>
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<h2>Outline</h2>
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<ol>
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<li>About Me</li>
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<li>Project history</li>
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<li>Why a new OS?</li>
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<li>What can it do?</li>
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<li>How do I use it?</li>
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</ol>
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</section>
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<section>
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<section>
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<h2>About Me</h2>
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<ul>
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<li>Live in Singapore</li>
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<li>Enjoy understanding systems</li>
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<li>Low-level is best</li>
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</ul>
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</section>
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<section>
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<h2>Novena: Open laptop</h2>
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<div class="r-hstack">
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<div>
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<img data-src="img/novena-1068_jpg_md-xl.jpg" height="400">
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</div>
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<div>
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<ul>
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<li>Always wanted custom laptop</li>
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<li>"Large" Cortex A9</li>
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<li>32 GB disk, 4 GB RAM</li>
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<li>Linux</li>
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</ul>
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</div>
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</div>
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</section>
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<section>
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<img data-src="img/novena-1089_jpg_project-body.jpg" height="600">
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</section>
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<section>
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<h2>Chibitronics: Programming for 8-year-olds</h2>
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<div class="r-hstack">
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<div>
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<img data-src="img/ltc.jpg" height="400">
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</div>
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<div>
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<ul>
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<li>Paper circuit design</li>
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<li>"Small" Cortex M0+</li>
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<li>32 kB flash, 4 kB RAM</li>
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<li>ChibiOS</li>
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</ul>
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</div>
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</div>
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</section>
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<section>
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<h2>Precursor Design</h2>
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<div class="r-hstack">
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<div>
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<img data-src="img/betrusted_pvt_blockdiag.png" height="500">
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</div>
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<div>
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<ul>
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<li>Two FPGA-based CPUs</li>
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<li>RV32IMAC based on VexRiscv</li>
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<li>128 MB flash, 16 MB RAM</li>
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<li class="fragment">Operating System?</li>
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</ul>
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</div>
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</div>
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</section>
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<section>
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<img data-src="img/a-r-m.png">
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</section>
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<section>
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<h2>MMUs are Amazing</h2>
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<ul>
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<li>XIP flash for free!</li>
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<li>Swap space</li>
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<li>Encrypted swap? No problem!</li>
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<li>Realtime patching broken hardware</li>
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</ul>
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</section>
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<section>
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<h2>Operating System Selection</h2>
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<ul>
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<li>MMU Required</li>
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<li>RISC-V</li>
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<li>Not Linux</li>
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<li class="fragment">Rust is a new thing?</li>
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</ul>
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</section>
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</section>
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<section>
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<section>
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<h2>Xous Design</h2>
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</section>
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<section>
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<h2>Brief Specs</h2>
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<ul>
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<li>Kernel is 17k sloc</li>
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<!-- * 6k of that is a RISC-V disassembler for optional GDB support -->
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<li>Threads</li>
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<li>Processes</li>
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<li>Tier 2 Rust support</li>
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<!-- * libstd -->
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</ul>
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</section>
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<section>
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<h2>Other Features</h2>
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<ul>
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<li>Microkernel</li>
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<li>Interrupts in userspace</li>
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<li>All drivers provided in user space</li>
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<li>Each page of memory is mapped once</li>
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<li>Services use well-defined API calls</li>
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<li class="fragment">Only <strong>stable</strong> Rust</li>
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<li class="fragment">No C compiler required</li>
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</ul>
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</section>
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<section>
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<h2>Messages are Everything</h2>
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<ul>
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<li>Messages form IPC</li>
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<li>Scalars or Pages</li>
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<li>Blocking or Nonblocking</li>
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</ul>
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</section>
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<section>
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<h2>Example: Sleeping</h2>
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<code>sleep(msec: usize)</code>
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<ol>
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<li>Connect to "ticktimer" server</li>
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<li>Send a `BlockingScalar` with desired duration</li>
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<li>Client will block until server replies</li>
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<li>Server calls `ReturnScalar()` after expiration</li>
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</ol>
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</section>
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<section>
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<h2>Example: Mutex</h2>
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<code>mutex.lock().unwrap()</code>
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<ol>
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<li>Fast path with <code>AtomicIsize</code></li>
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<li>Slow path by sending <code>LockMutex</code></li>
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<li>On unlock, contending thread will see poison and send <code>UnlockMutex</code></li>
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<li>Server will reply to <code>LockMutex</code> message to unblock the thread</li>
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</ol>
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</section>
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<section>
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<h2>How can I use it?</h2>
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<div class="r-hstack">
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<div>
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<img data-src="img/renode-networking.png">
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</div>
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<div>
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<ul>
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<li>Talk to system vendors -- get them to include MMUs!</li>
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<li>Emulation is easiest -- Renode support</li>
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</ul>
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</div>
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</section>
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</section>
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<section>
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<h2>Thank you!</h2>
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<h3>github.com/betrusted-io/xous-core</h3>
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<!-- <h3 class="fragment">Questions?</h3> -->
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</section>
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</div>
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</div>
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