61 lines
2.5 KiB
Markdown
61 lines
2.5 KiB
Markdown
# popcorn: A toy OS kernel
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**popcorn** 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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## Building
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Popcorn uses the `ninja` build tool, and generates the build files for it with
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the `generate_build.py` script. The other requirements are:
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* python 3 for generating the build config
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* The Jinja2 package is also required
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* clang
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* mtools
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* ninja
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* curl for downloading the toolchain
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### Setting up the cross toolchain
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If you have `clang` and `curl` installed, runing the `scripts/build_sysroot_clang.sh`
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script will download and build a nasm/binutils/LLVM toolchain configured for building
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Popcorn host binaries.
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### Building and running Popcorn
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Once the toolchain has been set up, running `generate_build.py` will set up the
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build configuration, and `ninja -C build` will actually run the build. If you
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have `qemu-system-x86_64` installed, the `qemu.sh` script will to run Popcorn
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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
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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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