From f2d2b233f3d019521c8c2d0c30bed80836ff5145 Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Sun, 28 Aug 2016 18:38:53 -0600
Subject: [PATCH] Simple, unsafe context switch
---
context/mod.rs | 14 ++++++++++++++
lib.rs | 20 ++++++++++++++++++--
2 files changed, 32 insertions(+), 2 deletions(-)
diff --git a/context/mod.rs b/context/mod.rs
index 3e5e8491..54877809 100644
--- a/context/mod.rs
+++ b/context/mod.rs
@@ -1,6 +1,8 @@
//! Context management
+use alloc::boxed::Box;
use collections::{BTreeMap, Vec};
+use core::mem;
use core::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
use spin::{Once, RwLock, RwLockReadGuard, RwLockWriteGuard};
@@ -61,6 +63,15 @@ impl ContextList {
let context_lock = self.new_context()?;
{
let mut context = context_lock.write();
+ let mut stack = Box::new([0; 4096]);
+ 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_stack(stack.as_ptr() as usize + offset);
+ context.kstack = Some(stack);
print!("{}", format!("{}: {:X}\n", context.id, func as usize));
}
Ok(context_lock)
@@ -108,6 +119,8 @@ pub struct Context {
pub id: usize,
/// The architecture specific context
pub arch: ArchContext,
+ /// Kernel stack
+ pub kstack: Option<Box<[u8]>>,
/// The open files in the scheme
pub files: Vec<Option<file::File>>
}
@@ -118,6 +131,7 @@ impl Context {
Context {
id: id,
arch: ArchContext::new(),
+ kstack: None,
files: Vec::new()
}
}
diff --git a/lib.rs b/lib.rs
index 3b1d6eb2..acdf0288 100644
--- a/lib.rs
+++ b/lib.rs
@@ -134,8 +134,24 @@ pub extern fn kmain() {
print!("{}", format!("BSP: {:?}\n", syscall::getpid()));
- if let Ok(context) = context::contexts_mut().spawn(context_test) {
-
+ let to_ptr = if let Ok(context_lock) = context::contexts_mut().spawn(context_test) {
+ print!("Spawned context\n");
+ let mut context = context_lock.write();
+ &mut context.arch as *mut arch::context::Context
+ } else {
+ 0 as *mut arch::context::Context
+ };
+
+ let from_ptr = if let Some(context_lock) = context::contexts().current() {
+ let mut context = context_lock.write();
+ &mut context.arch as *mut arch::context::Context
+ } else {
+ 0 as *mut arch::context::Context
+ };
+
+ if to_ptr as usize != 0 && from_ptr as usize != 0 {
+ print!("Switching\n");
+ unsafe { (&mut *from_ptr).switch_to(&mut *to_ptr); }
}
loop {
--
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