add interrupts and cpu exceptiopn handlers

Author: Alirexaa

.vscode/settings.json

@@ -0,0 +1,7 @@
+{
+    "editor.defaultFormatter": null,
+    "[rust]": {
+      "editor.defaultFormatter": "rust-lang.rust-analyzer",
+      "editor.formatOnSave": true
+    },
+  }

Cargo.toml

@@ -36,4 +36,9 @@ test-timeout = 300          # (in seconds)
 
 [[test]]
 name = "should_panic"
-harness = false
+harness = false
+
+[[test]]
+name = "stack_overflow"
+harness = false
+    

src/gdt.rs

@@ -0,0 +1,49 @@
+use lazy_static::lazy_static;
+use x86_64::instructions::tables::load_tss;
+use x86_64::registers::segmentation::{Segment, CS};
+use x86_64::structures::gdt::{self, Descriptor, GlobalDescriptorTable, SegmentSelector};
+use x86_64::structures::tss::TaskStateSegment;
+use x86_64::VirtAddr;
+pub const DOUBLE_FAULT_IST_INDEX: u16 = 0;
+
+lazy_static! {
+    static ref TSS: TaskStateSegment = {
+        let mut tss = TaskStateSegment::new();
+        tss.interrupt_stack_table[DOUBLE_FAULT_IST_INDEX as usize] = {
+            const STACK_SIZE: usize = 4096 * 5;
+            static mut STACK: [usize; STACK_SIZE] = [0; STACK_SIZE];
+            let stack_start = VirtAddr::from_ptr(unsafe { &STACK });
+            let stack_end = stack_start + STACK_SIZE;
+            stack_end
+        };
+        tss
+    };
+}
+
+lazy_static! {
+    static ref GDT: (GlobalDescriptorTable, Selectors) = {
+        let mut gdt = GlobalDescriptorTable::new();
+        let code_selector = gdt.add_entry(Descriptor::kernel_code_segment());
+        let tss_selector = gdt.add_entry(Descriptor::tss_segment(&TSS));
+        (
+            gdt,
+            Selectors {
+                code_selector,
+                tss_selector,
+            },
+        )
+    };
+}
+
+pub fn init() {
+    GDT.0.load();
+    unsafe {
+        CS::set_reg(GDT.1.code_selector);
+        load_tss(GDT.1.tss_selector);
+    }
+}
+
+struct Selectors {
+    code_selector: SegmentSelector,
+    tss_selector: SegmentSelector,
+}

src/interrupts.rs

@@ -0,0 +1,37 @@
+lazy_static! {
+    static ref IDT: InterruptDescriptorTable = {
+        let mut idt = InterruptDescriptorTable::new();
+        idt.breakpoint.set_handler_fn(breakpoint_handler);
+        unsafe {
+            idt.double_fault
+                .set_handler_fn(double_fault_handler)
+                .set_stack_index(gdt::DOUBLE_FAULT_IST_INDEX);
+        }
+        idt
+    };
+}
+
+use lazy_static::lazy_static;
+use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame};
+
+use crate::{gdt, println};
+pub fn init_idt() {
+    IDT.load();
+}
+
+extern "x86-interrupt" fn breakpoint_handler(stack_frame: InterruptStackFrame) {
+    println!("EXCEPTION: BREAKPOINT\n{:#?}", stack_frame);
+}
+
+extern "x86-interrupt" fn double_fault_handler(
+    stack_frame: InterruptStackFrame,
+    _error_code: u64,
+) -> ! {
+    panic!("EXCEPTION: DOUBLE FAULT\n{:#?}", stack_frame);
+}
+
+#[test_case]
+fn test_breakpoint_exception() {
+    // invoke a breakpoint exception
+    x86_64::instructions::interrupts::int3();
+}

src/lib.rs

@@ -1,13 +1,20 @@
 #![no_std]
-
 #![cfg_attr(test, no_main)]
 #![feature(custom_test_frameworks)]
 #![test_runner(crate::test_runner)]
 #![reexport_test_harness_main = "test_main"]
+#![feature(abi_x86_interrupt)]
 
 use core::panic::PanicInfo;
+pub mod gdt;
+pub mod interrupts;
 pub mod serial;
 pub mod vga_buffer;
+pub fn init() {
+    gdt::init();
+    interrupts::init_idt();
+}
+
 pub trait Testable {
     fn run(&self) -> ();
 }
@@ -22,7 +29,7 @@ where
         serial_println!("[ok]");
     }
 }
-    
+
 pub fn test_runner(tests: &[&dyn Testable]) {
     serial_println!("Running {} tests", tests.len());
     for test in tests {
@@ -42,6 +49,7 @@ pub fn test_panic_handler(info: &PanicInfo) -> ! {
 #[cfg(test)]
 #[no_mangle]
 pub extern "C" fn _start() -> ! {
+    init();
     test_main();
     loop {}
 }
@@ -66,4 +74,4 @@ pub fn exit_qemu(exit_code: QemuExitCode) {
         let mut port = Port::new(0xf4);
         port.write(exit_code as u32);
     }
-}
+}

src/main.rs

@@ -11,9 +11,19 @@ use rustos::println;
 pub extern "C" fn _start() -> ! {
     println!("Hello World{}", "!");
 
+    rustos::init();
+
+    fn stack_overflow() {
+        stack_overflow(); // for each recursion, the return address is pushed
+    }
+
+    stack_overflow();
+
     #[cfg(test)]
     test_main();
 
+    println!("It did not crash!");
+
     loop {}
 }
 
@@ -29,4 +39,4 @@ fn panic(info: &PanicInfo) -> ! {
 #[panic_handler]
 fn panic(info: &PanicInfo) -> ! {
     rustos::test_panic_handler(info)
-}
+}

tests/stack_overflow.rs

@@ -0,0 +1,62 @@
+#![no_main]
+#![no_std]
+#![feature(abi_x86_interrupt)]
+
+use core::panic::PanicInfo;
+
+use lazy_static::lazy_static;
+use rustos::{exit_qemu, QemuExitCode};
+use rustos::{gdt, serial_println};
+use x86_64::structures::idt::InterruptDescriptorTable;
+
+#[no_mangle]
+pub extern "C" fn _start() -> ! {
+    serial_println!("stack_overflow::stack_overflow...\t");
+    gdt::init();
+
+    init_test_idt();
+
+    // trigger a stack overflow
+    stack_overflow();
+
+    panic!("Execution continued after stack overflow");
+}
+
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    rustos::test_panic_handler(info)
+}
+
+#[allow(unconditional_recursion)]
+fn stack_overflow() {
+    stack_overflow(); // for each recursion, the return address is pushed
+    volatile::Volatile::new(0).read(); // prevent tail recursion optimizations
+}
+
+lazy_static! {
+    static ref TEST_IDT: InterruptDescriptorTable = {
+        let mut idt = InterruptDescriptorTable::new();
+        unsafe {
+            idt.double_fault
+                .set_handler_fn(test_double_fault_handler)
+                .set_stack_index(rustos::gdt::DOUBLE_FAULT_IST_INDEX);
+        }
+
+        idt
+    };
+}
+
+pub fn init_test_idt() {
+    TEST_IDT.load();
+}
+
+use x86_64::structures::idt::InterruptStackFrame;
+
+extern "x86-interrupt" fn test_double_fault_handler(
+    _stack_frame: InterruptStackFrame,
+    _error_code: u64,
+) -> ! {
+    serial_println!("[ok]");
+    exit_qemu(QemuExitCode::Success);
+    loop {}
+}