Merge branch 'master' of github.com:redox-os/kernel

arch/x86_64/src/acpi/mod.rs

@@ -3,6 +3,7 @@
 
 use core::intrinsics::{atomic_load, atomic_store};
 
+use interrupt;
 use memory::{allocate_frame, Frame};
 use paging::{entry, ActivePageTable, Page, PhysicalAddress, VirtualAddress};
 use start::kstart_ap;
@@ -87,7 +88,7 @@ pub fn init_sdt(sdt: &'static Sdt, active_table: &mut ActivePageTable) {
                         // Wait for trampoline ready
                         println!("        Waiting for AP {}", asp_local_apic.id);
                         while unsafe { atomic_load(ap_ready) } == 0 {
-                            unsafe { asm!("pause" : : : : "intel", "volatile") };
+                            interrupt::pause();
                         }
                         println!("        AP {} is ready!", asp_local_apic.id);
                     } else {

arch/x86_64/src/context.rs

@@ -93,6 +93,7 @@ impl Context {
         asm!("mov cr3, $0" : : "r"(self.cr3) : "memory" : "intel", "volatile");
         */
 
-        //CONTEXT_SWITCH_LOCK.store(false, Ordering::SeqCst);
+        // Unset global lock, set inside of kernel
+        CONTEXT_SWITCH_LOCK.store(false, Ordering::SeqCst);
     }
 }

arch/x86_64/src/interrupt.rs

@@ -26,6 +26,13 @@ pub unsafe fn halt() {
     asm!("hlt" : : : : "intel", "volatile");
 }
 
+/// Pause instruction
+/// Safe because it is similar to a NOP, and has no memory effects
+#[inline(always)]
+pub fn pause() {
+    unsafe { asm!("pause" : : : : "intel", "volatile"); }
+}
+
 /// Get a stack trace
 //TODO: Check for stack being mapped before dereferencing
 #[inline(never)]

arch/x86_64/src/start.rs

@@ -11,6 +11,7 @@ use display;
 use externs::memset;
 use gdt;
 use idt;
+use interrupt;
 use memory::{self, Frame};
 use paging::{self, entry, Page, PhysicalAddress, VirtualAddress};
 
@@ -92,7 +93,7 @@ pub unsafe extern fn kstart() -> ! {
         }
 
         // Initialize display
-        //display::init(&mut active_table);
+        display::init(&mut active_table);
 
         // Reset AP variables
         AP_COUNT.store(0, Ordering::SeqCst);
@@ -100,7 +101,7 @@ pub unsafe extern fn kstart() -> ! {
         HEAP_FRAME.store(0, Ordering::SeqCst);
 
         // Read ACPI tables, starts APs
-        //acpi::init(&mut active_table);
+        acpi::init(&mut active_table);
 
         // Map heap
         {
@@ -173,7 +174,7 @@ pub unsafe extern fn kstart_ap(stack_start: usize, stack_end: usize) -> ! {
                 assert_eq!(heap_start_page.p4_index(), heap_end_page.p4_index());
 
                 while HEAP_FRAME.load(Ordering::SeqCst) == 0 {
-                    asm!("pause" : : : : "intel", "volatile");
+                    interrupt::pause();
                 }
                 let frame = Frame::containing_address(PhysicalAddress::new(HEAP_FRAME.load(Ordering::SeqCst)));
 
@@ -188,7 +189,7 @@ pub unsafe extern fn kstart_ap(stack_start: usize, stack_end: usize) -> ! {
     let ap_number = AP_COUNT.fetch_add(1, Ordering::SeqCst);
 
     while ! BSP_READY.load(Ordering::SeqCst) {
-        asm!("pause" : : : : "intel", "volatile");
+        interrupt::pause();
     }
 
     kmain_ap(ap_number);

kernel/context/mod.rs

@@ -6,6 +6,7 @@ use core::mem;
 use core::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
 use spin::{Once, RwLock, RwLockReadGuard, RwLockWriteGuard};
 
+use arch;
 use arch::context::Context as ArchContext;
 use syscall::{Error, Result};
 
@@ -94,7 +95,8 @@ static CONTEXT_ID: AtomicUsize = ATOMIC_USIZE_INIT;
 pub fn init() {
     let mut contexts = contexts_mut();
     let context_lock = contexts.new_context().expect("could not initialize first context");
-    let context = context_lock.read();
+    let mut context = context_lock.write();
+    context.running = true;
     CONTEXT_ID.store(context.id, Ordering::SeqCst);
 }
 
@@ -118,8 +120,44 @@ pub fn contexts_mut() -> RwLockWriteGuard<'static, ContextList> {
 /// # Safety
 ///
 /// Do not call this while holding locks!
-pub unsafe fn context_switch() {
+pub unsafe fn switch() {
-//    current.arch.switch_to(&mut next.arch);
+    use core::ops::DerefMut;
+
+    // Set the global lock to avoid the unsafe operations below from causing issues
+    while arch::context::CONTEXT_SWITCH_LOCK.compare_and_swap(false, true, Ordering::SeqCst) {
+        arch::interrupt::pause();
+    }
+
+    let from_ptr = if let Some(context_lock) = contexts().current() {
+        let mut context = context_lock.write();
+        context.deref_mut() as *mut Context
+    } else {
+        print!("NO FROM_PTR\n");
+        return;
+    };
+
+    let mut to_ptr = 0 as *mut Context;
+
+    for (_pid, context_lock) in contexts().map.iter() {
+        let mut context = context_lock.write();
+        if ! context.running {
+            to_ptr = context.deref_mut() as *mut Context;
+            break;
+        }
+    }
+
+    if to_ptr as usize == 0 {
+        print!("NO TO_PTR\n");
+        return;
+    }
+
+    unsafe {
+        (&mut *from_ptr).running = false;
+        (&mut *to_ptr).running = true;
+        CONTEXT_ID.store((&mut *to_ptr).id, Ordering::SeqCst);
+        
+        (&mut *from_ptr).arch.switch_to(&mut (&mut *to_ptr).arch);
+    }
 }
 
 /// A context, which identifies either a process or a thread
@@ -127,6 +165,8 @@ pub unsafe fn context_switch() {
 pub struct Context {
     /// The ID of this context
     pub id: usize,
+    /// Running or not
+    pub running: bool,
     /// The architecture specific context
     pub arch: ArchContext,
     /// Kernel stack
@@ -140,6 +180,7 @@ impl Context {
     pub fn new(id: usize) -> Context {
         Context {
             id: id,
+            running: false,
             arch: ArchContext::new(),
             kstack: None,
             files: Vec::new()

kernel/lib.rs

@@ -121,8 +121,10 @@ pub mod syscall;
 pub mod tests;
 
 pub extern fn context_test() {
-    print!("TEST\n");
+    print!("Test\n");
+    unsafe { context::switch(); }
 
+    print!("Test halt\n");
     loop {
         unsafe { interrupt::enable_and_halt(); }
     }
@@ -134,26 +136,14 @@ pub extern fn kmain() {
 
     print!("{}", format!("BSP: {:?}\n", syscall::getpid()));
 
-    let to_ptr = if let Ok(context_lock) = context::contexts_mut().spawn(context_test) {
+    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); }
     }
 
+    print!("Main\n");
+    unsafe { context::switch(); }
+
+    print!("Main halt\n");
     loop {
         unsafe { interrupt::enable_and_halt(); }
     }