Improvements for context switching

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);