74 lines
1.8 KiB
Rust
74 lines
1.8 KiB
Rust
//! Context management
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use alloc::boxed::Box;
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use core::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
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use spin::{Once, RwLock, RwLockReadGuard, RwLockWriteGuard};
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pub use self::context::{Context, Status};
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pub use self::list::ContextList;
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pub use self::switch::switch;
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/// Context struct
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mod context;
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/// Context list
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mod list;
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/// Context switch function
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mod switch;
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/// Event handling
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pub mod event;
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/// File struct - defines a scheme and a file number
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pub mod file;
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/// Memory struct - contains a set of pages for a context
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pub mod memory;
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/// Limit on number of contexts
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pub const CONTEXT_MAX_CONTEXTS: usize = 65536;
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/// Maximum context files
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pub const CONTEXT_MAX_FILES: usize = 65536;
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/// Contexts list
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static CONTEXTS: Once<RwLock<ContextList>> = Once::new();
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#[thread_local]
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static CONTEXT_ID: AtomicUsize = ATOMIC_USIZE_INIT;
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pub fn init() {
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let mut contexts = contexts_mut();
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let context_lock = contexts.new_context().expect("could not initialize first context");
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let mut context = context_lock.write();
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let mut fx = unsafe { Box::from_raw(::alloc::heap::allocate(512, 16) as *mut [u8; 512]) };
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for b in fx.iter_mut() {
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*b = 0;
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}
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context.arch.set_fx(fx.as_ptr() as usize);
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context.kfx = Some(fx);
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context.status = Status::Runnable;
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context.running = true;
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CONTEXT_ID.store(context.id, Ordering::SeqCst);
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}
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/// Initialize contexts, called if needed
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fn init_contexts() -> RwLock<ContextList> {
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RwLock::new(ContextList::new())
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}
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/// Get the global schemes list, const
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pub fn contexts() -> RwLockReadGuard<'static, ContextList> {
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CONTEXTS.call_once(init_contexts).read()
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}
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/// Get the global schemes list, mutable
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pub fn contexts_mut() -> RwLockWriteGuard<'static, ContextList> {
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CONTEXTS.call_once(init_contexts).write()
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}
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pub fn context_id() -> usize {
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CONTEXT_ID.load(Ordering::SeqCst)
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}
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