Move main to start

arch/x86_64/src/start.rs

@@ -0,0 +1,73 @@
+/// This function is where the kernel sets up IRQ handlers
+/// It is increcibly unsafe, and should be minimal in nature
+/// It must create the IDT with the correct entries, those entries are
+/// defined in other files inside of the `arch` module
+
+use allocator::{HEAP_START, HEAP_SIZE};
+use externs::memset;
+use gdt;
+use idt;
+use memory;
+use paging::{self, Page, VirtualAddress};
+
+/// Test of zero values in BSS.
+static BSS_TEST_ZERO: usize = 0;
+/// Test of non-zero values in BSS.
+static BSS_TEST_NONZERO: usize = 0xFFFFFFFFFFFFFFFF;
+
+extern {
+    /// Kernel main function
+    fn kmain() -> !;
+}
+
+#[no_mangle]
+pub unsafe extern fn kstart() -> ! {
+    extern {
+        /// The starting byte of the _.bss_ (uninitialized data) segment.
+        static mut __bss_start: u8;
+        /// The ending byte of the _.bss_ (uninitialized data) segment.
+        static mut __bss_end: u8;
+    }
+
+    // Zero BSS, this initializes statics that are set to 0
+    {
+        let start_ptr = &mut __bss_start as *mut u8;
+        let end_ptr = & __bss_end as *const u8 as usize;
+
+        if start_ptr as usize <= end_ptr {
+            let size = end_ptr - start_ptr as usize;
+            memset(start_ptr, 0, size);
+        }
+
+        debug_assert_eq!(BSS_TEST_ZERO, 0);
+        debug_assert_eq!(BSS_TEST_NONZERO, 0xFFFFFFFFFFFFFFFF);
+    }
+
+    // Set up GDT
+    gdt::init();
+
+    // Set up IDT
+    idt::init(blank);
+
+    // Initialize memory management
+    let mut allocator = memory::init(0, &__bss_end as *const u8 as usize);
+
+    // Initialize paging
+    let mut active_table = paging::init(&mut allocator);
+
+    // Initialize heap
+    let heap_start_page = Page::containing_address(VirtualAddress::new(HEAP_START));
+    let heap_end_page = Page::containing_address(VirtualAddress::new(HEAP_START + HEAP_SIZE-1));
+
+    for page in Page::range_inclusive(heap_start_page, heap_end_page) {
+        active_table.map(page, paging::entry::WRITABLE, &mut allocator);
+    }
+
+    asm!("xchg bx, bx" : : : : "intel", "volatile");
+    kmain();
+}
+
+interrupt!(blank, {
+    asm!("xchg bx, bx" : : : : "intel", "volatile");
+    println!("INTERRUPT");
+});