Cleanup Redox repo, update Rust, remove old target

kernel/src/context/list.rs

@@ -0,0 +1,91 @@
+use alloc::arc::Arc;
+use alloc::boxed::Box;
+use collections::BTreeMap;
+use core::mem;
+use core::sync::atomic::Ordering;
+use spin::RwLock;
+
+use arch;
+use syscall::error::{Result, Error, EAGAIN};
+use super::context::{Context, ContextId};
+
+/// Context list type
+pub struct ContextList {
+    map: BTreeMap<ContextId, Arc<RwLock<Context>>>,
+    next_id: usize
+}
+
+impl ContextList {
+    /// Create a new context list.
+    pub fn new() -> Self {
+        ContextList {
+            map: BTreeMap::new(),
+            next_id: 1
+        }
+    }
+
+    /// Get the nth context.
+    pub fn get(&self, id: ContextId) -> Option<&Arc<RwLock<Context>>> {
+        self.map.get(&id)
+    }
+
+    /// Get the current context.
+    pub fn current(&self) -> Option<&Arc<RwLock<Context>>> {
+        self.map.get(&super::CONTEXT_ID.load(Ordering::SeqCst))
+    }
+
+    pub fn iter(&self) -> ::collections::btree_map::Iter<ContextId, Arc<RwLock<Context>>> {
+        self.map.iter()
+    }
+
+    /// Create a new context.
+    pub fn new_context(&mut self) -> Result<&Arc<RwLock<Context>>> {
+        if self.next_id >= super::CONTEXT_MAX_CONTEXTS {
+            self.next_id = 1;
+        }
+
+        while self.map.contains_key(&ContextId::from(self.next_id)) {
+            self.next_id += 1;
+        }
+
+        if self.next_id >= super::CONTEXT_MAX_CONTEXTS {
+            return Err(Error::new(EAGAIN));
+        }
+
+        let id = ContextId::from(self.next_id);
+        self.next_id += 1;
+
+        assert!(self.map.insert(id, Arc::new(RwLock::new(Context::new(id)))).is_none());
+
+        Ok(self.map.get(&id).expect("Failed to insert new context. ID is out of bounds."))
+    }
+
+    /// Spawn a context from a function.
+    pub fn spawn(&mut self, func: extern fn()) -> Result<&Arc<RwLock<Context>>> {
+        let context_lock = self.new_context()?;
+        {
+            let mut context = context_lock.write();
+            let mut fx = unsafe { Box::from_raw(::alloc::heap::allocate(512, 16) as *mut [u8; 512]) };
+            for b in fx.iter_mut() {
+                *b = 0;
+            }
+            let mut stack = vec![0; 65536].into_boxed_slice();
+            let offset = stack.len() - mem::size_of::<usize>();
+            unsafe {
+                let offset = stack.len() - mem::size_of::<usize>();
+                let func_ptr = stack.as_mut_ptr().offset(offset as isize);
+                *(func_ptr as *mut usize) = func as usize;
+            }
+            context.arch.set_page_table(unsafe { arch::paging::ActivePageTable::new().address() });
+            context.arch.set_fx(fx.as_ptr() as usize);
+            context.arch.set_stack(stack.as_ptr() as usize + offset);
+            context.kfx = Some(fx);
+            context.kstack = Some(stack);
+        }
+        Ok(context_lock)
+    }
+
+    pub fn remove(&mut self, id: ContextId) -> Option<Arc<RwLock<Context>>> {
+        self.map.remove(&id)
+    }
+}