| commit | 934409ba17bf517026e8b02455ad64baf3326e80 | [log] [tgz] |
|---|---|---|
| author | James Farrell <[email protected]> | Tue Oct 01 22:05:21 2024 +0000 |
| committer | James Farrell <[email protected]> | Tue Oct 01 22:05:21 2024 +0000 |
| tree | ee39b30414c05c5e89f77afeee7b030ad078f346 | |
| parent | 2ebf0ceb876708b7a1c07bf387f5a22b7e4a4d76 [diff] |
Migrate 20 crates to monorepo gdbstub gdbstub_arch glam gpio-cdev grpcio-compiler half hex hound hyper-timeout ident_case indexmap linkme-impl mockall_derive moveit octets openssl-macros percore petgraph plotters protobuf-json-mapping Bug: http://b/339424309 Test: treehugger Change-Id: Ic3b6f8fbcd830877bee0f29b785d71ef956c4c7a
Safe per-CPU core mutable state on no_std platforms through exception masking.
This crate provides two main wrapper types: PerCore to provide an instance of a value per CPU core, where each core can access only its instance, and ExceptionLock to guard a value so that it can only be accessed while exceptions are masked. These may be combined with RefCell to provide safe per-core mutable state.
ExceptionLock may also be combined with a spinlock-based mutex (such as one provided by the spin crate) to avoid deadlocks when accessing global mutable state from exception handlers.
use core::cell::RefCell; use percore::{exception_free, Cores, ExceptionLock, PerCore}; /// The total number of CPU cores in the target system. const CORE_COUNT: usize = 2; struct CoresImpl; unsafe impl Cores for CoresImpl { fn core_index() -> usize { todo!("Return the index of the current CPU core, 0 or 1") } } struct CoreState { // Your per-core mutable state goes here... foo: u32, } const EMPTY_CORE_STATE: ExceptionLock<RefCell<CoreState>> = ExceptionLock::new(RefCell::new(CoreState { foo: 0 })); static CORE_STATE: PerCore<ExceptionLock<RefCell<CoreState>>, CoresImpl, CORE_COUNT> = PerCore::new([EMPTY_CORE_STATE; CORE_COUNT]); fn main() { // Mask exceptions while accessing mutable state. exception_free(|token| { // `token` proves that interrupts are masked, so we can safely access per-core mutable // state. CORE_STATE.get().borrow_mut(token).foo = 42; }); }
This is not an officially supported Google product.
Currently only aarch64 is fully supported. The crate will build for other architectures, but you'll need to provide your own implementation of the exception_free function. Patches are welcome to add support for other architectures.
Licensed under either of
at your option.
If you want to contribute to the project, see details of how we accept contributions.