// Copyright 2016 Philipp Oppermann. See the README.md
// file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

#![feature(lang_items)]
#![feature(const_fn, unique)]
#![feature(alloc, collections)]
#![feature(asm)]
#![feature(naked_functions)]
#![feature(core_intrinsics)]
#![no_std]

extern crate rlibc;
extern crate volatile;
extern crate spin;
extern crate multiboot2;
#[macro_use]
extern crate bitflags;
#[macro_use]
extern crate x86;
#[macro_use]
extern crate once;
extern crate bit_field;
#[macro_use]
extern crate lazy_static;

extern crate hole_list_allocator;
extern crate alloc;
#[macro_use]
extern crate collections;

#[macro_use]
mod vga_buffer;
mod memory;

mod interrupts;

#[no_mangle]
pub extern "C" fn rust_main(multiboot_information_address: usize) {
    // ATTENTION: we have a very small stack and no guard page
    vga_buffer::clear_screen();
    println!("Hello World{}", "!");

    let boot_info = unsafe { multiboot2::load(multiboot_information_address) };
    enable_nxe_bit();
    enable_write_protect_bit();

    // set up guard page and map the heap pages
    let mut memory_controller = memory::init(boot_info);

    // initialize our IDT
    interrupts::init(&mut memory_controller);

    fn stack_overflow() {
        stack_overflow(); // for each recursion, the return address is pushed
    }

    // trigger a stack overflow
    stack_overflow();

    println!("It did not crash!");
    loop {}
}

fn enable_nxe_bit() {
    use x86::shared::msr::{IA32_EFER, rdmsr, wrmsr};

    let nxe_bit = 1 << 11;
    unsafe {
        let efer = rdmsr(IA32_EFER);
        wrmsr(IA32_EFER, efer | nxe_bit);
    }
}

fn enable_write_protect_bit() {
    use x86::shared::control_regs::{cr0, cr0_write, CR0_WRITE_PROTECT};

    unsafe { cr0_write(cr0() | CR0_WRITE_PROTECT) };
}

#[cfg(not(test))]
#[lang = "eh_personality"]
extern "C" fn eh_personality() {}

#[cfg(not(test))]
#[lang = "panic_fmt"]
#[no_mangle]
extern "C" fn panic_fmt(fmt: core::fmt::Arguments, file: &'static str, line: u32) -> ! {
    println!("\n\nPANIC in {} at line {}:", file, line);
    println!("    {}", fmt);
    loop {}
}

#[allow(non_snake_case)]
#[no_mangle]
pub extern "C" fn _Unwind_Resume() -> ! {
    loop {}
}