Re-entrant syscall is tricky because we end up smashing the return thread context and stack of the current syscall. We stash the thread context and stack in order to make this happen, but we have to make some assumption about the potential stack size. There's a assert to save us if this is wrong, but generally the kernel is extremely well behaved on stack consumption so we shouldn't be bumping into it. This version of the OOM handler allows us to bury the OOM handler "anywhere", which means we can handle the hard OOM in multiple allocation methods without having to track the entry and exit point of every single possible one. This means we can chop a lot of fragile code out of the kernel. We'll do that after this commit, and some testing, to make sure this is the right path, but it feels "much nicer". We'll probably also cut the oom-doomer, because I think in practice it won't be effective and it consumes a non-trivial amount of RAM, which would otherwise make OOMs more infrequent -- probably an amount that would be greater than the benefit that any soft-OOM handler can get us. |
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| .. | ||
| bin | ||
| src | ||
| assemble.ps1 | ||
| assemble.sh | ||
| build.rs | ||
| Cargo.toml | ||
| link.x | ||
| README.md | ||
Xous Kernel
This contains the core kernel for Xous. It requires a stage 1 loader in order to start up, as it assumes the system is already running in Supervisor mode.
Building
To build the kernel, you will need a riscv32 target for Rust. Possible
targets include riscv32i-unknown-none-elf, riscv32imac-unknown-none-elf,
or riscv32imac-unknown-xous-elf.
- Decide what target you want. For simple, embedded systems this could
be
riscv32i-unknown-none-elf, and for more complex systems with compressed instructions you could useriscv32imac-unknown-none-elf. - Get Rust. Go to https://rustup.rs/ and follow its instructions.
- Install the proper toolchain:
rustup target add ${target_arch} - Build the kernel:
cargo build --release --target ${target_arch}
Using
To use the kernel, you must package it up into an arguments binary with
xous-tools.
Testing
TBD
Contribution Guidelines
Please see CONTRIBUTING for details on how to make a contribution.
Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide its terms.
License
Copyright © 2020
This project is licensed under the Apache License 2.0 LICENSE. For accurate information, please check individual files.