76 lines
2.5 KiB
Markdown
76 lines
2.5 KiB
Markdown
# Writing an Operating System in 1,000 Lines
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My implementation of https://operating-system-in-1000-lines.vercel.app/en
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A small operating system written from scratch for RISC-V CPU architecture
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This project will have basic context switching, paging, user mode, a command-line shell, a disk device driver, and file read/write operations in C.
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And also I'll try to add some more functionality to it
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# Getting Started
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You have to be on UNIS-like OS to run this OS. If you're on Windows you need to install WSL2 (Windows Subsystem for Linux) and follow Ubuntu instructions
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## Install tools
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### macOS
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Install [Homebrew](https://brew.sh) and run this command to get all tools you need:
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```
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brew install llvm lld qemu
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```
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Also, you need to add LLVM binutils to your `PATH`:
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```
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$ export PATH="$PATH:$(brew --prefix)/opt/llvm/bin"
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$ which llvm-objcopy
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/opt/homebrew/opt/llvm/bin/llvm-objcopy
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```
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### Ubuntu
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Install packages with `apt`:
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```
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sudo apt update && sudo apt install -y clang llvm lld qemu-system-riscv32 curl
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```
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Also, download OpenSBI (think of it as BIOS/UEFI for PCs):
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```
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curl -LO https://github.com/qemu/qemu/raw/v8.0.4/pc-bios/opensbi-riscv32-generic-fw_dynamic.bin
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```
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> [!WARNING]
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>
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> When you run QEMU, make sure `opensbi-riscv32-generic-fw_dynamic.bin` is in your current directory. If it's not, you'll see this error:
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>
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> ```
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> qemu-system-riscv32: Unable to load the RISC-V firmware "opensbi-riscv32-generic-fw_dynamic.bin"
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> ```
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### Other OS users
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If you are using other OSes, get the following tools:
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- `bash`: The command-line shell. Usually it's pre-installed.
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- `tar`: Usually it's pre-installed. Prefer GNU version, not BSD.
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- `clang`: C compiler. Make sure it supports 32-bit RISC-V CPU (see below).
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- `lld`: LLVM linker, which bundles complied object files into an executable.
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- `llvm-objcopy`: Object file editor. It comes with the LLVM package (typically `llvm` package).
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- `llvm-objdump`: A disassembler. Same as `llvm-objcopy`.
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- `llvm-readelf`: An ELF file reader. Same as `llvm-objcopy`.
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- `qemu-system-riscv32`: 32-bit RISC-V CPU emulator. It's part of the QEMU package (typically `qemu` package).
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> [!TIP]
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>
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> To check if your `clang` supports 32-bit RISC-V CPU, run this command:
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>
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> ```
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> $ clang -print-targets | grep riscv32
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> riscv32 - 32-bit RISC-V
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> ```
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>
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> You should see `riscv32`. Note pre-installed clang on macOS won't show this. That's why you need to install another `clang` in Homebrew's `llvm` package.
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