xous-core/kernel
bunnie bfb25af370 make hard OOM a re-entrant syscall
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.
2024-05-25 00:06:38 +08:00
..
bin add the .a artifacts to the tree for the asm.S 2024-01-06 16:41:40 +08:00
src make hard OOM a re-entrant syscall 2024-05-25 00:06:38 +08:00
assemble.ps1 kernel: asm: align kernel stack to 16 bytes 2023-12-29 18:15:48 +08:00
assemble.sh kernel: asm: align kernel stack to 16 bytes 2023-12-29 18:15:48 +08:00
build.rs ok, format the kernel now that all in-line assembly has been checked 2024-01-14 19:27:14 +08:00
Cargo.toml add test and debug deps/features 2024-05-18 00:22:23 +08:00
link.x add an "endcap" to the kernel region 2023-01-17 23:07:05 +08:00
README.md adding license info to README 2021-01-25 14:57:39 +01:00

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.

  1. 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 use riscv32imac-unknown-none-elf.
  2. Get Rust. Go to https://rustup.rs/ and follow its instructions.
  3. Install the proper toolchain: rustup target add ${target_arch}
  4. 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

Contributor Covenant

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.