79 lines
3.2 KiB
Markdown
79 lines
3.2 KiB
Markdown
# jsix: A toy OS kernel
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**jsix** is the kernel for the hobby OS that I am currently building. It's
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far from finished, or even being usable. Instead, it's a sandbox for me to play
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with kernel-level code and explore architectures.
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The design goals of the project are:
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* Modernity - I'm not interested in designing for legacy systems, or running on
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all hardware out there. My target is only 64 bit architecutres, and modern
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commodity hardware. Currently that means x64 systems with Nehalem or newer
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CPUs and UEFI firmware. Eventually I'd like to work on an AArch64 port,
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partly to force myself to factor out the architecture-dependent pieces of the
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code base.
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* Modularity - I'd like to pull as much of the system out into separate
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processes as possible, in the microkernel fashion. A sub-goal of this is to
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explore where the bottlenecks of such a microkernel are now, and whether
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eschewing legacy hardware will let me design a system that's less bogged down
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by the traditional microkernel problems. Given that there are no processes
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yet, the kernel is monolithic by default.
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* Exploration - I'm really mostly doing this to have fun learning and exploring
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modern OS development. Modular design may be tossed out (hopefully
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temporarily) in some places to allow me to play around with the related
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hardware.
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A note on the name: This kernel was originally named Popcorn, but I have since
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discovered that the Popcorn Linux project is also developing a kernel with that
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name, started around the same time as this project. So I've renamed this kernel
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jsix (Always styled _jsix_ or `j6`, never capitalized) as an homage to L4, xv6,
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and my wonderful wife.
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## Building
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jsix uses the [Ninja][] build tool, and generates the build files for it with a
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custom tool called [Bonnibel][]. Bonnibel can be installed with [Cargo][], or
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downloaded as a prebuilt binary from its Github repository.
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[Ninja]: https://ninja-build.org
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[Bonnibel]: https://github.com/justinian/bonnibel
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[Cargo]: https://crates.io/crates/bonnibel
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Requrirements:
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* bonnibel
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* ninja
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* clang
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* nasm
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* mtools
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* curl for downloading the toolchain
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### Setting up the cross toolchain
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Running `pb sync` will download and unpack the toolchain into `sysroot`.
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#### Compiling the toolchain yourself
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If you have `clang` and `curl` installed, runing the `scripts/build_sysroot.sh`
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script will download and build a LLVM toolchain configured for building jsix
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host binaries.
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### Building and running jsix
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Once the toolchain has been set up, running Bonnibel's `pb init` command will
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set up the build configuration, and `pb build` will actually run the build. If
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you have `qemu-system-x86_64` installed, the `qemu.sh` script will to run jsix
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in QEMU `-nographic` mode.
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I personally run this either from a real debian amd64 testing/buster machine or
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a windows WSL debian testing/buster installation. The following should be
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enough to set up such a system to build the kernel:
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sudo apt install qemu-system-x86 nasm clang-6.0 mtools curl
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sudo update-alternatives /usr/bin/clang clang /usr/bin/clang-6.0 1000
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sudo update-alternatives /usr/bin/clang++ clang++ /usr/bin/clang++-6.0 1000
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curl -L -o pb https://github.com/justinian/bonnibel/releases/download/2.0.0/pb_linux_amd64 && chmod a+x pb
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