Merge branch 'post-04' into post-05

Fix: `target-pointer-width` field now expects an integer

Cargo.lock

@@ -34,9 +34,9 @@ dependencies = [
 
 [[package]]
 name = "bootloader"
-version = "0.9.32"
+version = "0.9.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1ea119c3ed05625c179e09d17d0914570a3753ca09c890a73d98f6b72aea00d2"
+checksum = "7bdfddac270bbdd45903296bc1caf29a7fdce6b326aaf0bbab7f04c5f98b7447"
 
 [[package]]
 name = "lazy_static"

Cargo.toml

@@ -8,10 +8,6 @@ edition = "2024"
 name = "should_panic"
 harness = false
 
-[[test]]
-name = "stack_overflow"
-harness = false
-
 [dependencies]
 bootloader = "0.9"
 volatile = "0.2.6"

README.md

@@ -1,10 +1,10 @@
-# Blog OS (Double Faults)
+# Blog OS (CPU Exceptions)
 
-[![Build Status](https://github.com/phil-opp/blog_os/workflows/Code/badge.svg?branch=post-06)](https://github.com/phil-opp/blog_os/actions?query=workflow%3A%22Code%22+branch%3Apost-06)
+[![Build Status](https://github.com/phil-opp/blog_os/workflows/Code/badge.svg?branch=post-05)](https://github.com/phil-opp/blog_os/actions?query=workflow%3A%22Code%22+branch%3Apost-05)
 
-This repository contains the source code for the [Double Faults][post] post of the [Writing an OS in Rust](https://os.phil-opp.com) series.
+This repository contains the source code for the [CPU Exceptions][post] post of the [Writing an OS in Rust](https://os.phil-opp.com) series.
 
-[post]: https://os.phil-opp.com/double-fault-exceptions/
+[post]: https://os.phil-opp.com/cpu-exceptions/
 
 **Check out the [master branch](https://github.com/phil-opp/blog_os) for more information.**
 

src/gdt.rs

@@ -1,52 +0,0 @@
-use lazy_static::lazy_static;
-use x86_64::VirtAddr;
-use x86_64::structures::gdt::{Descriptor, GlobalDescriptorTable, SegmentSelector};
-use x86_64::structures::tss::TaskStateSegment;
-
-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: [u8; STACK_SIZE] = [0; STACK_SIZE];
-
-            let stack_start = VirtAddr::from_ptr(&raw const 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,
-            },
-        )
-    };
-}
-
-struct Selectors {
-    code_selector: SegmentSelector,
-    tss_selector: SegmentSelector,
-}
-
-pub fn init() {
-    use x86_64::instructions::segmentation::{CS, Segment};
-    use x86_64::instructions::tables::load_tss;
-
-    GDT.0.load();
-    unsafe {
-        CS::set_reg(GDT.1.code_selector);
-        load_tss(GDT.1.tss_selector);
-    }
-}

src/interrupts.rs

@@ -1,4 +1,4 @@
-use crate::{gdt, println};
+use crate::println;
 use lazy_static::lazy_static;
 use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame};
 
@@ -6,11 +6,6 @@ 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
     };
 }
@@ -23,13 +18,6 @@ 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

src/lib.rs

@@ -7,13 +7,11 @@
 
 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 {

src/main.rs

@@ -13,12 +13,8 @@ pub extern "C" fn _start() -> ! {
 
     blog_os::init();
 
-    fn stack_overflow() {
-        stack_overflow(); // for each recursion, the return address is pushed
-    }
-
-    // uncomment line below to trigger a stack overflow
-    // stack_overflow();
+    // invoke a breakpoint exception
+    x86_64::instructions::interrupts::int3();
 
     #[cfg(test)]
     test_main();

tests/stack_overflow.rs

@@ -1,58 +0,0 @@
-#![no_std]
-#![no_main]
-#![feature(abi_x86_interrupt)]
-
-use blog_os::{QemuExitCode, exit_qemu, serial_print, serial_println};
-use core::panic::PanicInfo;
-use lazy_static::lazy_static;
-use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame};
-
-#[unsafe(no_mangle)]
-pub extern "C" fn _start() -> ! {
-    serial_print!("stack_overflow::stack_overflow...\t");
-
-    blog_os::gdt::init();
-    init_test_idt();
-
-    // trigger a stack overflow
-    stack_overflow();
-
-    panic!("Execution continued after stack overflow");
-}
-
-#[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(blog_os::gdt::DOUBLE_FAULT_IST_INDEX);
-        }
-
-        idt
-    };
-}
-
-pub fn init_test_idt() {
-    TEST_IDT.load();
-}
-
-extern "x86-interrupt" fn test_double_fault_handler(
-    _stack_frame: InterruptStackFrame,
-    _error_code: u64,
-) -> ! {
-    serial_println!("[ok]");
-    exit_qemu(QemuExitCode::Success);
-    loop {}
-}
-
-#[panic_handler]
-fn panic(info: &PanicInfo) -> ! {
-    blog_os::test_panic_handler(info)
-}

x86_64-blog_os.json

@@ -3,7 +3,7 @@
     "data-layout": "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128",
     "arch": "x86_64",
     "target-endian": "little",
-    "target-pointer-width": "64",
+    "target-pointer-width": 64,
     "target-c-int-width": 32,
     "os": "none",
     "executables": true,