Organize context module
This commit is contained in:
Jeremy Soller
parent
a4f8613971
commit
fbbfe16764
87
kernel/context/context.rs
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87
kernel/context/context.rs
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@ -0,0 +1,87 @@
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use alloc::boxed::Box;
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use collections::Vec;
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use arch;
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use super::file::File;
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use super::memory::Memory;
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/// A context, which identifies either a process or a thread
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#[derive(Debug)]
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pub struct Context {
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/// The ID of this context
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pub id: usize,
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//TODO: Status enum
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/// Running or not
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pub running: bool,
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/// Blocked or not
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pub blocked: bool,
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/// Exited or not`
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pub exited: bool,
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/// The architecture specific context
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pub arch: arch::context::Context,
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/// Kernel stack
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pub kstack: Option<Box<[u8]>>,
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/// Executable image
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pub image: Vec<Memory>,
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/// User heap
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pub heap: Option<Memory>,
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/// User stack
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pub stack: Option<Memory>,
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/// The open files in the scheme
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pub files: Vec<Option<File>>
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}
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impl Context {
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/// Create a new context
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pub fn new(id: usize) -> Context {
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Context {
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id: id,
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running: false,
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blocked: true,
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exited: false,
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arch: arch::context::Context::new(),
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kstack: None,
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image: Vec::new(),
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heap: None,
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stack: None,
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files: Vec::new()
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}
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}
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/// Add a file to the lowest available slot.
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/// Return the file descriptor number or None if no slot was found
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pub fn add_file(&mut self, file: File) -> Option<usize> {
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for (i, mut file_option) in self.files.iter_mut().enumerate() {
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if file_option.is_none() {
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*file_option = Some(file);
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return Some(i);
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}
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}
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let len = self.files.len();
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if len < super::CONTEXT_MAX_FILES {
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self.files.push(Some(file));
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Some(len)
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} else {
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None
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}
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}
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/// Get a file
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pub fn get_file(&self, i: usize) -> Option<File> {
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if i < self.files.len() {
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self.files[i]
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} else {
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None
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}
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}
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/// Remove a file
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// TODO: adjust files vector to smaller size if possible
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pub fn remove_file(&mut self, i: usize) -> Option<File> {
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if i < self.files.len() {
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self.files[i].take()
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} else {
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None
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}
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}
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}
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80
kernel/context/list.rs
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80
kernel/context/list.rs
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@ -0,0 +1,80 @@
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use alloc::boxed::Box;
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use collections::BTreeMap;
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use core::mem;
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use core::sync::atomic::Ordering;
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use spin::RwLock;
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use arch;
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use syscall::{Result, Error};
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use super::context::Context;
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/// Context list type
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pub struct ContextList {
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map: BTreeMap<usize, RwLock<Context>>,
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next_id: usize
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}
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impl ContextList {
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/// Create a new context list.
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pub fn new() -> Self {
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ContextList {
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map: BTreeMap::new(),
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next_id: 1
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}
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}
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/// Get the nth context.
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pub fn get(&self, id: usize) -> Option<&RwLock<Context>> {
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self.map.get(&id)
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}
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/// Get the current context.
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pub fn current(&self) -> Option<&RwLock<Context>> {
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self.map.get(&super::CONTEXT_ID.load(Ordering::SeqCst))
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}
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pub fn iter(&self) -> ::collections::btree_map::Iter<usize, RwLock<Context>> {
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self.map.iter()
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}
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/// Create a new context.
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pub fn new_context(&mut self) -> Result<&RwLock<Context>> {
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if self.next_id >= super::CONTEXT_MAX_CONTEXTS {
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self.next_id = 1;
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}
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while self.map.contains_key(&self.next_id) {
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self.next_id += 1;
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}
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if self.next_id >= super::CONTEXT_MAX_CONTEXTS {
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return Err(Error::TryAgain);
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}
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let id = self.next_id;
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self.next_id += 1;
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assert!(self.map.insert(id, RwLock::new(Context::new(id))).is_none());
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Ok(self.map.get(&id).expect("Failed to insert new context. ID is out of bounds."))
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}
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/// Spawn a context from a function.
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pub fn spawn(&mut self, func: extern fn()) -> Result<&RwLock<Context>> {
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let context_lock = self.new_context()?;
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{
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let mut context = context_lock.write();
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let mut stack = Box::new([0; 65536]);
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let offset = stack.len() - mem::size_of::<usize>();
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unsafe {
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let offset = stack.len() - mem::size_of::<usize>();
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let func_ptr = stack.as_mut_ptr().offset(offset as isize);
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*(func_ptr as *mut usize) = func as usize;
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}
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context.arch.set_page_table(unsafe { arch::paging::ActivePageTable::new().address() });
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context.arch.set_stack(stack.as_ptr() as usize + offset);
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context.kstack = Some(stack);
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}
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Ok(context_lock)
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}
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}
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@ -1,19 +1,25 @@
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//! Context management
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use alloc::boxed::Box;
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use collections::{BTreeMap, Vec};
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use core::mem;
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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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use arch;
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use arch::context::Context as ArchContext;
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use syscall::{Error, Result};
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pub use self::context::Context;
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pub use self::list::ContextList;
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pub use self::switch::switch;
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/// File operations
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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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/// File struct - defines a scheme and a file number
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pub mod file;
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/// Memory operations
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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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@ -22,73 +28,6 @@ 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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/// Context list type
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pub struct ContextList {
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map: BTreeMap<usize, RwLock<Context>>,
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next_id: usize
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}
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impl ContextList {
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/// Create a new context list.
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pub fn new() -> Self {
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ContextList {
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map: BTreeMap::new(),
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next_id: 1
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}
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}
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/// Get the nth context.
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pub fn get(&self, id: usize) -> Option<&RwLock<Context>> {
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self.map.get(&id)
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}
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/// Get the current context.
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pub fn current(&self) -> Option<&RwLock<Context>> {
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self.map.get(&CONTEXT_ID.load(Ordering::SeqCst))
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}
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/// Create a new context.
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pub fn new_context(&mut self) -> Result<&RwLock<Context>> {
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if self.next_id >= CONTEXT_MAX_CONTEXTS {
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self.next_id = 1;
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}
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while self.map.contains_key(&self.next_id) {
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self.next_id += 1;
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}
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if self.next_id >= CONTEXT_MAX_CONTEXTS {
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return Err(Error::TryAgain);
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}
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let id = self.next_id;
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self.next_id += 1;
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assert!(self.map.insert(id, RwLock::new(Context::new(id))).is_none());
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Ok(self.map.get(&id).expect("Failed to insert new context. ID is out of bounds."))
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}
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/// Spawn a context from a function.
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pub fn spawn(&mut self, func: extern fn()) -> Result<&RwLock<Context>> {
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let context_lock = self.new_context()?;
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{
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let mut context = context_lock.write();
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let mut stack = Box::new([0; 65536]);
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let offset = stack.len() - mem::size_of::<usize>();
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unsafe {
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let offset = stack.len() - mem::size_of::<usize>();
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let func_ptr = stack.as_mut_ptr().offset(offset as isize);
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*(func_ptr as *mut usize) = func as usize;
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}
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context.arch.set_page_table(unsafe { arch::paging::ActivePageTable::new().address() });
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context.arch.set_stack(stack.as_ptr() as usize + offset);
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context.kstack = Some(stack);
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}
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Ok(context_lock)
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}
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}
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/// Contexts list
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static CONTEXTS: Once<RwLock<ContextList>> = Once::new();
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@ -118,145 +57,3 @@ pub fn contexts() -> RwLockReadGuard<'static, ContextList> {
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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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/// Switch to the next context
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///
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/// # Safety
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///
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/// Do not call this while holding locks!
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pub unsafe fn switch() {
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use core::ops::DerefMut;
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// Set the global lock to avoid the unsafe operations below from causing issues
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while arch::context::CONTEXT_SWITCH_LOCK.compare_and_swap(false, true, Ordering::SeqCst) {
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arch::interrupt::pause();
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}
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let from_ptr = {
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let contexts = contexts();
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let context_lock = contexts.current().expect("context::switch: Not inside of context");
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let mut context = context_lock.write();
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context.deref_mut() as *mut Context
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};
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let mut to_ptr = 0 as *mut Context;
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for (pid, context_lock) in contexts().map.iter() {
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if *pid > (*from_ptr).id {
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let mut context = context_lock.write();
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if ! context.running && ! context.blocked && ! context.exited {
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to_ptr = context.deref_mut() as *mut Context;
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break;
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}
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}
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}
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if to_ptr as usize == 0 {
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for (pid, context_lock) in contexts().map.iter() {
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if *pid < (*from_ptr).id {
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let mut context = context_lock.write();
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if ! context.running && ! context.blocked && ! context.exited {
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to_ptr = context.deref_mut() as *mut Context;
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break;
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}
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}
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}
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}
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if to_ptr as usize == 0 {
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// TODO: Sleep, wait for interrupt
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// Unset global lock if no context found
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arch::context::CONTEXT_SWITCH_LOCK.store(false, Ordering::SeqCst);
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return;
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}
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(&mut *from_ptr).running = false;
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(&mut *to_ptr).running = true;
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if let Some(ref stack) = (*to_ptr).kstack {
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arch::gdt::TSS.rsp[0] = (stack.as_ptr() as usize + stack.len() - 256) as u64;
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}
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CONTEXT_ID.store((&mut *to_ptr).id, Ordering::SeqCst);
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(&mut *from_ptr).arch.switch_to(&mut (&mut *to_ptr).arch);
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}
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/// A context, which identifies either a process or a thread
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#[derive(Debug)]
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pub struct Context {
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/// The ID of this context
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pub id: usize,
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//TODO: Status enum
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/// Running or not
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pub running: bool,
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/// Blocked or not
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pub blocked: bool,
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/// Exited or not`
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pub exited: bool,
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/// The architecture specific context
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pub arch: ArchContext,
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/// Kernel stack
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pub kstack: Option<Box<[u8]>>,
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/// Executable image
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pub image: Vec<memory::Memory>,
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/// User heap
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pub heap: Option<memory::Memory>,
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/// User stack
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pub stack: Option<memory::Memory>,
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/// The open files in the scheme
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pub files: Vec<Option<file::File>>
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}
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impl Context {
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/// Create a new context
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pub fn new(id: usize) -> Context {
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Context {
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id: id,
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running: false,
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blocked: true,
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exited: false,
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arch: ArchContext::new(),
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kstack: None,
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image: Vec::new(),
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heap: None,
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stack: None,
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files: Vec::new()
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}
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}
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/// Add a file to the lowest available slot.
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/// Return the file descriptor number or None if no slot was found
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pub fn add_file(&mut self, file: file::File) -> Option<usize> {
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for (i, mut file_option) in self.files.iter_mut().enumerate() {
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if file_option.is_none() {
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*file_option = Some(file);
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return Some(i);
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}
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}
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let len = self.files.len();
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if len < CONTEXT_MAX_FILES {
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self.files.push(Some(file));
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Some(len)
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} else {
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None
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}
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}
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/// Get a file
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pub fn get_file(&self, i: usize) -> Option<file::File> {
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if i < self.files.len() {
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self.files[i]
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} else {
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None
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}
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}
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/// Remove a file
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// TODO: adjust files vector to smaller size if possible
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pub fn remove_file(&mut self, i: usize) -> Option<file::File> {
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if i < self.files.len() {
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self.files[i].take()
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} else {
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None
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}
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}
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}
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65
kernel/context/switch.rs
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65
kernel/context/switch.rs
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@ -0,0 +1,65 @@
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use core::sync::atomic::Ordering;
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use arch;
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use super::{contexts, Context, CONTEXT_ID};
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/// Switch to the next context
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///
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/// # Safety
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///
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/// Do not call this while holding locks!
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pub unsafe fn switch() {
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use core::ops::DerefMut;
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// Set the global lock to avoid the unsafe operations below from causing issues
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while arch::context::CONTEXT_SWITCH_LOCK.compare_and_swap(false, true, Ordering::SeqCst) {
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arch::interrupt::pause();
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}
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let from_ptr = {
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let contexts = contexts();
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let context_lock = contexts.current().expect("context::switch: Not inside of context");
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let mut context = context_lock.write();
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context.deref_mut() as *mut Context
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};
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let mut to_ptr = 0 as *mut Context;
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for (pid, context_lock) in contexts().iter() {
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if *pid > (*from_ptr).id {
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let mut context = context_lock.write();
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if ! context.running && ! context.blocked && ! context.exited {
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to_ptr = context.deref_mut() as *mut Context;
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break;
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}
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}
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}
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if to_ptr as usize == 0 {
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for (pid, context_lock) in contexts().iter() {
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if *pid < (*from_ptr).id {
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let mut context = context_lock.write();
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if ! context.running && ! context.blocked && ! context.exited {
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to_ptr = context.deref_mut() as *mut Context;
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break;
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}
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}
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}
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}
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if to_ptr as usize == 0 {
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// TODO: Sleep, wait for interrupt
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// Unset global lock if no context found
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arch::context::CONTEXT_SWITCH_LOCK.store(false, Ordering::SeqCst);
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return;
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}
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(&mut *from_ptr).running = false;
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(&mut *to_ptr).running = true;
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if let Some(ref stack) = (*to_ptr).kstack {
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arch::gdt::TSS.rsp[0] = (stack.as_ptr() as usize + stack.len() - 256) as u64;
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}
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CONTEXT_ID.store((&mut *to_ptr).id, Ordering::SeqCst);
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(&mut *from_ptr).arch.switch_to(&mut (&mut *to_ptr).arch);
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}
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