stack allocator, keyboard doesnt work with interrupts yet, i think i need to tell 0x20 and 0x21 to shift interrupt by 32 because of intel bug. tomorrow

kernel-rs/src/interrupts/mod.rs

@@ -4,16 +4,30 @@ lazy_static! {
     static ref IDT: Idt = {
         let mut idt = Idt::new();
         idt.breakpoint.set_handler_fn(breakpoint_handler);
+        idt.double_fault.set_handler_fn(double_fault_handler);
+        idt[0x21].set_handler_fn(::keyboard::kbd_callback);
         idt
     };
 }
 
-pub fn init() {
+pub fn init(memory_controller: &mut ::memory::MemoryController) {
+    let double_fault_stack = memory_controller.alloc_stack(1)
+        .expect("could not allocate double fault stack");
+    // println!("DF stack: {:#?}", double_fault_stack);
+    // flush!();
     IDT.load();
 }
 
+extern "x86-interrupt" fn double_fault_handler(
+    stack_frame: &mut ExceptionStackFrame, _error_code: u32)
+{
+    println!("EXCEPTION: DOUBLE FAULT\n{:#?}", stack_frame);
+    flush!();
+}
+
 extern "x86-interrupt" fn breakpoint_handler(
     stack_frame: &mut ExceptionStackFrame)
 {
     println!("EXCEPTION: BREAKPOINT\n{:#?}", stack_frame);
+    flush!();
 }

kernel-rs/src/keyboard.rs

@@ -1,4 +1,5 @@
 extern crate core;
+use x86::structures::idt::*;
 
 use cpuio;
 use vga;
@@ -76,7 +77,10 @@ fn check_key_state(key: u8) -> (bool, usize) {
     }
 }
 
-pub fn kbd_callback() {
+pub extern "x86-interrupt" fn kbd_callback(
+    stack_frame: &mut ExceptionStackFrame) {
+    println!("kbd callback called");
+    flush!();
     static mut SHIFT: bool = false;
     static mut CTRL: bool = false;
     static mut ALT: bool = false;

kernel-rs/src/lib.rs

@@ -37,6 +37,7 @@ fn init_kernel(multiboot_info_addr: usize) -> Result <(), &'static str> {
 
     let boot_info = unsafe { multiboot2::load(multiboot_info_addr)};
 
+    // ACPI must be intialized BEFORE paging (memory::init()) is active
     if let Some(rsdp) = boot_info.rsdp_v2_tag() {
         acpi::load(rsdp)?;
     } else if let Some(rsdp) = boot_info.rsdp_tag() {
@@ -45,11 +46,8 @@ fn init_kernel(multiboot_info_addr: usize) -> Result <(), &'static str> {
         acpi::init()?;
     }
 
-    enable_paging();
+    let mut memory_controller = memory::init(&boot_info);
-    enable_write_protect_bit();
+    interrupts::init(&mut memory_controller);
-
-    memory::init(&boot_info);
-    interrupts::init();
     vga::init();
 
     Ok(())
@@ -62,11 +60,16 @@ pub extern fn kmain(multiboot_info_addr: usize) -> ! {
         cpuio::halt();
     }
 
-    x86::instructions::interrupts::int3();
+    // x86::instructions::interrupts::int3();
 
-    flush!();
+    // fn stack_overflow() { stack_overflow(); }
+    // stack_overflow();
 
-    loop { keyboard::kbd_callback(); }
+    // unsafe {
+    //     *(0xdead as *mut u32) = 42;
+    // };
+
+    loop {}
 }
 
 #[lang = "eh_personality"] #[no_mangle]

kernel-rs/src/memory/mod.rs

@@ -1,11 +1,11 @@
-pub const PAGE_SIZE: usize = 4096;
-
 mod area_allocator;
 mod heap_allocator;
+mod stack_allocator;
 mod paging;
 
 pub use self::area_allocator::*;
 pub use self::heap_allocator::*;
+pub use self::stack_allocator::*;
 pub use self::paging::remap_the_kernel;
 use multiboot2;
 use x86::*;
@@ -16,8 +16,25 @@ pub trait FrameAllocator {
     fn deallocate_frame(&mut self, frame: PhysFrame);
 }
 
+pub struct MemoryController {
+    active_table: paging::ActivePageTable,
+    frame_allocator: AreaFrameAllocator,
+    stack_allocator: StackAllocator,
+}
+
+impl MemoryController {
+    pub fn alloc_stack(&mut self, size_in_pages: usize) -> Option<Stack> {
+        let &mut MemoryController { ref mut active_table,
+                                      ref mut frame_allocator,
+                                      ref mut stack_allocator } = self;
+
+        stack_allocator.alloc_stack(active_table, frame_allocator,
+                                    size_in_pages)
+    }
+}
+
 /// memory initialisation should only be called once
-pub fn init(boot_info: &multiboot2::BootInformation) {
+pub fn init(boot_info: &multiboot2::BootInformation) -> MemoryController {
     use x86::registers::control::{Cr0, Cr4, Cr0Flags, Cr4Flags};
     Cr4::add(Cr4Flags::PSE);
     Cr0::add(Cr0Flags::PAGING | Cr0Flags::WRITE_PROTECT);
@@ -52,4 +69,17 @@ pub fn init(boot_info: &multiboot2::BootInformation) {
     for page in heap_start_page..heap_end_page {
         active_table.map(page, PageTableFlags::WRITABLE, &mut frame_allocator);
     }
+
+    let stack_allocator = {
+        let stack_alloc_start = heap_end_page + 1;
+        let stack_alloc_end = stack_alloc_start + 100;
+        let stack_alloc_range = stack_alloc_start..stack_alloc_end + 1;
+        StackAllocator::new(stack_alloc_range)
+    };
+
+    MemoryController {
+        active_table,
+        frame_allocator,
+        stack_allocator,
+    }
 }

kernel-rs/src/memory/stack_allocator.rs

@@ -0,0 +1,81 @@
+use x86::*;
+use x86::structures::paging::*;
+use memory::paging::{self, ActivePageTable};
+use memory::*;
+use core::ops::Range;
+
+#[derive(Debug)]
+pub struct Stack {
+    top: usize,
+    bottom: usize,
+}
+
+impl Stack {
+    fn new (top: usize, bottom: usize) -> Stack {
+        assert!(top > bottom);
+        Stack {
+            top,
+            bottom,
+        }
+    }
+
+    pub fn top(&self) -> usize {
+        self.top
+    }
+
+    pub fn bottom(&self) -> usize {
+        self.bottom
+    }
+}
+
+#[derive(Debug)]
+pub struct StackAllocator {
+    range: Range<Page>
+}
+
+impl StackAllocator {
+    pub fn new(range: Range<Page>) -> StackAllocator {
+        StackAllocator { range }
+    }
+
+    pub fn alloc_stack<FA: FrameAllocator>(&mut self,
+                                           active_table: &mut ActivePageTable,
+                                           frame_allocator: &mut FA,
+                                           size_in_pages: usize) -> Option<Stack> {
+        if size_in_pages == 0 {
+            return None; /* a zero sized stack makes no sense */
+        }
+
+        // clone the range, since we only want to change it on success
+        let mut range = self.range.clone();
+
+        // try to allocate the stack pages and a guard page
+        let guard_page = range.next();
+        let stack_start = range.next();
+        let stack_end = if size_in_pages == 1 {
+            stack_start
+        } else {
+            // choose the (size_in_pages-2)th element, since index
+            // starts at 0 and we already allocated the start page
+            range.nth(size_in_pages - 2)
+        };
+
+        match (guard_page, stack_start, stack_end) {
+            (Some(_), Some(start), Some(end)) => {
+                // success! write back updated range
+                self.range = range.clone();
+
+                // map stack pages to physical frames
+                for page in range {
+                    active_table.map(page, PageTableFlags::WRITABLE, frame_allocator);
+                }
+
+                // create a new stack
+                let top_of_stack = end.start_address().as_u32() + PAGE_SIZE as u32;
+                Some(Stack::new(top_of_stack as usize,
+                                start.start_address().as_u32() as usize))
+            }
+            _ => None, /* not enough pages */
+        }
+    }
+}