Align the double fault stack through a new wrapper type

Cargo.lock

@@ -1,10 +1,13 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
 [[package]]
-name = "autocfg"
+name = "array-init"
-version = "1.0.0"
+version = "0.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f8aac770f1885fd7e387acedd76065302551364496e46b3dd00860b2f8359b9d"
+checksum = "23589ecb866b460d3a0f1278834750268c607e8e28a1b982c907219f3178cd72"
+dependencies = [
+ "nodrop",
+]
 
 [[package]]
 name = "bit_field"
@@ -23,93 +26,26 @@ name = "blog_os"
 version = "0.1.0"
 dependencies = [
  "bootloader",
- "conquer-once",
- "crossbeam-queue",
- "futures-util",
  "lazy_static",
- "linked_list_allocator",
- "pc-keyboard",
- "pic8259_simple",
  "spin",
  "uart_16550",
  "volatile",
- "x86_64",
+ "x86_64 0.8.1",
 ]
 
 [[package]]
 name = "bootloader"
-version = "0.8.8"
+version = "0.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c3ed4f735c4e455ba86a3d2939b1c0729414153642106c9d035693355630a42c"
+checksum = "d596849a47f28abdea62d7a6a25c4f6e69c3d9b09b0a2877db6e9cda004ca993"
 
 [[package]]
-name = "cfg-if"
+name = "cast"
-version = "0.1.10"
+version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
+checksum = "4b9434b9a5aa1450faa3f9cb14ea0e8c53bb5d2b3c1bfd1ab4fc03e9f33fbfb0"
-
-[[package]]
-name = "conquer-once"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6f7644600a548ecad74e4a918392af1798f7dd045be610be3203b9e129b4f98f"
 dependencies = [
- "conquer-util",
+ "rustc_version",
-]
-
-[[package]]
-name = "conquer-util"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "654fb2472cc369d311c547103a1fa81d467bef370ae7a0680f65939895b1182a"
-
-[[package]]
-name = "cpuio"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "22b8e308ccfc5acf3b82f79c0eac444cf6114cb2ac67a230ca6c177210068daa"
-
-[[package]]
-name = "crossbeam-queue"
-version = "0.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c695eeca1e7173472a32221542ae469b3e9aac3a4fc81f7696bcad82029493db"
-dependencies = [
- "cfg-if",
- "crossbeam-utils",
-]
-
-[[package]]
-name = "crossbeam-utils"
-version = "0.7.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c3c7c73a2d1e9fc0886a08b93e98eb643461230d5f1925e4036204d5f2e261a8"
-dependencies = [
- "autocfg",
- "cfg-if",
-]
-
-[[package]]
-name = "futures-core"
-version = "0.3.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f25592f769825e89b92358db00d26f965761e094951ac44d3663ef25b7ac464a"
-
-[[package]]
-name = "futures-task"
-version = "0.3.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7b0a34e53cf6cdcd0178aa573aed466b646eb3db769570841fda0c7ede375a27"
-
-[[package]]
-name = "futures-util"
-version = "0.3.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "22766cf25d64306bedf0384da004d05c9974ab104fcc4528f1236181c18004c5"
-dependencies = [
- "futures-core",
- "futures-task",
- "pin-utils",
 ]
 
 [[package]]
@@ -122,49 +58,34 @@ dependencies = [
 ]
 
 [[package]]
-name = "linked_list_allocator"
+name = "nodrop"
-version = "0.8.0"
+version = "0.1.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "18c618c431dfe4419afbe22852f6aceffbc17bd82ba0a18b982def291000824c"
+checksum = "72ef4a56884ca558e5ddb05a1d1e7e1bfd9a68d9ed024c21704cc98872dae1bb"
+
+[[package]]
+name = "rustc_version"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
 dependencies = [
- "spinning_top",
+ "semver",
 ]
 
 [[package]]
-name = "lock_api"
+name = "semver"
-version = "0.3.3"
+version = "0.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "79b2de95ecb4691949fea4716ca53cdbcfccb2c612e19644a8bad05edcf9f47b"
+checksum = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
 dependencies = [
- "scopeguard",
+ "semver-parser",
 ]
 
 [[package]]
-name = "pc-keyboard"
+name = "semver-parser"
-version = "0.5.0"
+version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c48392db76c4e9a69e0b3be356c5f97ebb7b14413c5e4fd0af4755dbf86e2fce"
+checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
-
-[[package]]
-name = "pic8259_simple"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dc64b2fd10828da8521b6cdabe0679385d7d2a3a6d4c336b819d1fa31ba35c72"
-dependencies = [
- "cpuio",
-]
-
-[[package]]
-name = "pin-utils"
-version = "0.1.0-alpha.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5894c618ce612a3fa23881b152b608bafb8c56cfc22f434a3ba3120b40f7b587"
-
-[[package]]
-name = "scopeguard"
-version = "1.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
 
 [[package]]
 name = "spin"
@@ -173,23 +94,20 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6e63cff320ae2c57904679ba7cb63280a3dc4613885beafb148ee7bf9aa9042d"
 
 [[package]]
-name = "spinning_top"
+name = "uart_16550"
-version = "0.1.0"
+version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "32d801a3a53bcf5071f85fef8d5cab9e5f638fc5580a37e6eb7aba4b37438d24"
+checksum = "803ea8cb602dbb32c1a657a866d2dd79fe7dbeab0fb2ac667cb4dcc7de12a58b"
 dependencies = [
- "lock_api",
+ "bitflags",
+ "x86_64 0.7.7",
 ]
 
 [[package]]
-name = "uart_16550"
+name = "ux"
-version = "0.2.4"
+version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d44b0f30cb82b0fbc15b78ade1064226529ad52028bc8cb8accb98ff6f3d7131"
+checksum = "88dfeb711b61ce620c0cb6fd9f8e3e678622f0c971da2a63c4b3e25e88ed012f"
-dependencies = [
- "bitflags",
- "x86_64",
-]
 
 [[package]]
 name = "volatile"
@@ -199,10 +117,25 @@ checksum = "6af0edf5b4faacc31fc51159244d78d65ec580f021afcef7bd53c04aeabc7f29"
 
 [[package]]
 name = "x86_64"
-version = "0.9.6"
+version = "0.7.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4206b60c9f99766329b66962aa8ddc01df6c7edd02edc046b7a69d5df9fcdbcf"
+checksum = "1f27d9168654aee1b0c1b73746caeb4aa33248f8b8c8f6e100e697fcc2a794b2"
 dependencies = [
+ "array-init",
  "bit_field",
  "bitflags",
+ "cast",
+ "ux",
+]
+
+[[package]]
+name = "x86_64"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f21672dcbed52bc09eea030d189600c0189c66c97bc5b31779eb780e064a201f"
+dependencies = [
+ "array-init",
+ "bit_field",
+ "bitflags",
+ "cast",
 ]

Cargo.toml

@@ -13,32 +13,16 @@ name = "stack_overflow"
 harness = false
 
 [dependencies]
-bootloader = { version = "0.8.0", features = ["map_physical_memory"]}
+bootloader = "0.8.0"
 volatile = "0.2.6"
 spin = "0.5.2"
-x86_64 = "0.9.6"
+x86_64 = "0.8.1"
 uart_16550 = "0.2.0"
-pic8259_simple = "0.1.1"
-pc-keyboard = "0.5.0"
-linked_list_allocator = "0.8.0"
 
 [dependencies.lazy_static]
 version = "1.0"
 features = ["spin_no_std"]
 
-[dependencies.crossbeam-queue]
-version = "0.2.1"
-default-features = false
-features = ["alloc"]
-
-[dependencies.futures-util]
-version = "0.3.4"
-default-features = false
-features = ["alloc", "async-await"]
-
-[dependencies.conquer-once]
-version = "0.2.0"
-default-features = false
 
 [package.metadata.bootimage]
 test-args = [

README.md

@@ -1,10 +1,10 @@
-# Blog OS (Heap Allocation)
+# Blog OS (Double Faults)
 
-[![Build Status](https://github.com/phil-opp/blog_os/workflows/Build%20Code/badge.svg?branch=post-10)](https://github.com/phil-opp/blog_os/actions?query=workflow%3A%22Build+Code%22+branch%3Apost-10)
+[![Build Status](https://github.com/phil-opp/blog_os/workflows/Build%20Code/badge.svg?branch=post-06)](https://github.com/phil-opp/blog_os/actions?query=workflow%3A%22Build+Code%22+branch%3Apost-06)
 
-This repository contains the source code for the [Heap Allocation][post] post of the [Writing an OS in Rust](https://os.phil-opp.com) series.
+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.
 
-[post]: https://os.phil-opp.com/heap-allocation/
+[post]: https://os.phil-opp.com/double-fault-exceptions/
 
 **Check out the [master branch](https://github.com/phil-opp/blog_os) for more information.**
 

src/allocator.rs

@@ -1,82 +0,0 @@
-use alloc::alloc::{GlobalAlloc, Layout};
-use core::ptr::null_mut;
-use fixed_size_block::FixedSizeBlockAllocator;
-use x86_64::{
-    structures::paging::{
-        mapper::MapToError, FrameAllocator, Mapper, Page, PageTableFlags, Size4KiB,
-    },
-    VirtAddr,
-};
-
-pub mod bump;
-pub mod fixed_size_block;
-pub mod linked_list;
-
-pub const HEAP_START: usize = 0x_4444_4444_0000;
-pub const HEAP_SIZE: usize = 100 * 1024; // 100 KiB
-
-#[global_allocator]
-static ALLOCATOR: Locked<FixedSizeBlockAllocator> = Locked::new(FixedSizeBlockAllocator::new());
-
-pub fn init_heap(
-    mapper: &mut impl Mapper<Size4KiB>,
-    frame_allocator: &mut impl FrameAllocator<Size4KiB>,
-) -> Result<(), MapToError<Size4KiB>> {
-    let page_range = {
-        let heap_start = VirtAddr::new(HEAP_START as u64);
-        let heap_end = heap_start + HEAP_SIZE - 1u64;
-        let heap_start_page = Page::containing_address(heap_start);
-        let heap_end_page = Page::containing_address(heap_end);
-        Page::range_inclusive(heap_start_page, heap_end_page)
-    };
-
-    for page in page_range {
-        let frame = frame_allocator
-            .allocate_frame()
-            .ok_or(MapToError::FrameAllocationFailed)?;
-        let flags = PageTableFlags::PRESENT | PageTableFlags::WRITABLE;
-        mapper.map_to(page, frame, flags, frame_allocator)?.flush();
-    }
-
-    unsafe {
-        ALLOCATOR.lock().init(HEAP_START, HEAP_SIZE);
-    }
-
-    Ok(())
-}
-
-pub struct Dummy;
-
-unsafe impl GlobalAlloc for Dummy {
-    unsafe fn alloc(&self, _layout: Layout) -> *mut u8 {
-        null_mut()
-    }
-
-    unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {
-        panic!("dealloc should be never called")
-    }
-}
-
-/// A wrapper around spin::Mutex to permit trait implementations.
-pub struct Locked<A> {
-    inner: spin::Mutex<A>,
-}
-
-impl<A> Locked<A> {
-    pub const fn new(inner: A) -> Self {
-        Locked {
-            inner: spin::Mutex::new(inner),
-        }
-    }
-
-    pub fn lock(&self) -> spin::MutexGuard<A> {
-        self.inner.lock()
-    }
-}
-
-/// Align the given address `addr` upwards to alignment `align`.
-///
-/// Requires that `align` is a power of two.
-fn align_up(addr: usize, align: usize) -> usize {
-    (addr + align - 1) & !(align - 1)
-}

src/allocator/bump.rs

@@ -1,61 +0,0 @@
-use super::{align_up, Locked};
-use alloc::alloc::{GlobalAlloc, Layout};
-use core::ptr;
-
-pub struct BumpAllocator {
-    heap_start: usize,
-    heap_end: usize,
-    next: usize,
-    allocations: usize,
-}
-
-impl BumpAllocator {
-    /// Creates a new empty bump allocator.
-    pub const fn new() -> Self {
-        BumpAllocator {
-            heap_start: 0,
-            heap_end: 0,
-            next: 0,
-            allocations: 0,
-        }
-    }
-
-    /// Initializes the bump allocator with the given heap bounds.
-    ///
-    /// This method is unsafe because the caller must ensure that the given
-    /// memory range is unused. Also, this method must be called only once.
-    pub unsafe fn init(&mut self, heap_start: usize, heap_size: usize) {
-        self.heap_start = heap_start;
-        self.heap_end = heap_start.saturating_add(heap_size);
-        self.next = heap_start;
-    }
-}
-
-unsafe impl GlobalAlloc for Locked<BumpAllocator> {
-    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
-        let mut bump = self.lock(); // get a mutable reference
-
-        let alloc_start = align_up(bump.next, layout.align());
-        let alloc_end = match alloc_start.checked_add(layout.size()) {
-            Some(end) => end,
-            None => return ptr::null_mut(),
-        };
-
-        if alloc_end > bump.heap_end {
-            ptr::null_mut() // out of memory
-        } else {
-            bump.next = alloc_end;
-            bump.allocations += 1;
-            alloc_start as *mut u8
-        }
-    }
-
-    unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {
-        let mut bump = self.lock(); // get a mutable reference
-
-        bump.allocations -= 1;
-        if bump.allocations == 0 {
-            bump.next = bump.heap_start;
-        }
-    }
-}

src/allocator/fixed_size_block.rs

@@ -1,102 +0,0 @@
-use super::Locked;
-use alloc::alloc::{GlobalAlloc, Layout};
-use core::{
-    mem,
-    ptr::{self, NonNull},
-};
-
-/// The block sizes to use.
-///
-/// The sizes must each be power of 2 because they are also used as
-/// the block alignment (alignments must be always powers of 2).
-const BLOCK_SIZES: &[usize] = &[8, 16, 32, 64, 128, 256, 512, 1024, 2048];
-
-/// Choose an appropriate block size for the given layout.
-///
-/// Returns an index into the `BLOCK_SIZES` array.
-fn list_index(layout: &Layout) -> Option<usize> {
-    let required_block_size = layout.size().max(layout.align());
-    BLOCK_SIZES.iter().position(|&s| s >= required_block_size)
-}
-
-struct ListNode {
-    next: Option<&'static mut ListNode>,
-}
-
-pub struct FixedSizeBlockAllocator {
-    list_heads: [Option<&'static mut ListNode>; BLOCK_SIZES.len()],
-    fallback_allocator: linked_list_allocator::Heap,
-}
-
-impl FixedSizeBlockAllocator {
-    /// Creates an empty FixedSizeBlockAllocator.
-    pub const fn new() -> Self {
-        FixedSizeBlockAllocator {
-            list_heads: [None; BLOCK_SIZES.len()],
-            fallback_allocator: linked_list_allocator::Heap::empty(),
-        }
-    }
-
-    /// Initialize the allocator with the given heap bounds.
-    ///
-    /// This function is unsafe because the caller must guarantee that the given
-    /// heap bounds are valid and that the heap is unused. This method must be
-    /// called only once.
-    pub unsafe fn init(&mut self, heap_start: usize, heap_size: usize) {
-        self.fallback_allocator.init(heap_start, heap_size);
-    }
-
-    /// Allocates using the fallback allocator.
-    fn fallback_alloc(&mut self, layout: Layout) -> *mut u8 {
-        match self.fallback_allocator.allocate_first_fit(layout) {
-            Ok(ptr) => ptr.as_ptr(),
-            Err(_) => ptr::null_mut(),
-        }
-    }
-}
-
-unsafe impl GlobalAlloc for Locked<FixedSizeBlockAllocator> {
-    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
-        let mut allocator = self.lock();
-        match list_index(&layout) {
-            Some(index) => {
-                match allocator.list_heads[index].take() {
-                    Some(node) => {
-                        allocator.list_heads[index] = node.next.take();
-                        node as *mut ListNode as *mut u8
-                    }
-                    None => {
-                        // no block exists in list => allocate new block
-                        let block_size = BLOCK_SIZES[index];
-                        // only works if all block sizes are a power of 2
-                        let block_align = block_size;
-                        let layout = Layout::from_size_align(block_size, block_align).unwrap();
-                        allocator.fallback_alloc(layout)
-                    }
-                }
-            }
-            None => allocator.fallback_alloc(layout),
-        }
-    }
-
-    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
-        let mut allocator = self.lock();
-        match list_index(&layout) {
-            Some(index) => {
-                let new_node = ListNode {
-                    next: allocator.list_heads[index].take(),
-                };
-                // verify that block has size and alignment required for storing node
-                assert!(mem::size_of::<ListNode>() <= BLOCK_SIZES[index]);
-                assert!(mem::align_of::<ListNode>() <= BLOCK_SIZES[index]);
-                let new_node_ptr = ptr as *mut ListNode;
-                new_node_ptr.write(new_node);
-                allocator.list_heads[index] = Some(&mut *new_node_ptr);
-            }
-            None => {
-                let ptr = NonNull::new(ptr).unwrap();
-                allocator.fallback_allocator.deallocate(ptr, layout);
-            }
-        }
-    }
-}

src/allocator/linked_list.rs

@@ -1,145 +0,0 @@
-use super::{align_up, Locked};
-use alloc::alloc::{GlobalAlloc, Layout};
-use core::{mem, ptr};
-
-struct ListNode {
-    size: usize,
-    next: Option<&'static mut ListNode>,
-}
-
-impl ListNode {
-    const fn new(size: usize) -> Self {
-        ListNode { size, next: None }
-    }
-
-    fn start_addr(&self) -> usize {
-        self as *const Self as usize
-    }
-
-    fn end_addr(&self) -> usize {
-        self.start_addr() + self.size
-    }
-}
-
-pub struct LinkedListAllocator {
-    head: ListNode,
-}
-
-impl LinkedListAllocator {
-    /// Creates an empty LinkedListAllocator.
-    pub const fn new() -> Self {
-        Self {
-            head: ListNode::new(0),
-        }
-    }
-
-    /// Initialize the allocator with the given heap bounds.
-    ///
-    /// This function is unsafe because the caller must guarantee that the given
-    /// heap bounds are valid and that the heap is unused. This method must be
-    /// called only once.
-    pub unsafe fn init(&mut self, heap_start: usize, heap_size: usize) {
-        self.add_free_region(heap_start, heap_size);
-    }
-
-    /// Adds the given memory region to the front of the list.
-    unsafe fn add_free_region(&mut self, addr: usize, size: usize) {
-        // ensure that the freed region is capable of holding ListNode
-        assert!(align_up(addr, mem::align_of::<ListNode>()) == addr);
-        assert!(size >= mem::size_of::<ListNode>());
-
-        // create a new list node and append it at the start of the list
-        let mut node = ListNode::new(size);
-        node.next = self.head.next.take();
-        let node_ptr = addr as *mut ListNode;
-        node_ptr.write(node);
-        self.head.next = Some(&mut *node_ptr)
-    }
-
-    /// Looks for a free region with the given size and alignment and removes
-    /// it from the list.
-    ///
-    /// Returns a tuple of the list node and the start address of the allocation.
-    fn find_region(&mut self, size: usize, align: usize) -> Option<(&'static mut ListNode, usize)> {
-        // reference to current list node, updated for each iteration
-        let mut current = &mut self.head;
-        // look for a large enough memory region in linked list
-        while let Some(ref mut region) = current.next {
-            if let Ok(alloc_start) = Self::alloc_from_region(&region, size, align) {
-                // region suitable for allocation -> remove node from list
-                let next = region.next.take();
-                let ret = Some((current.next.take().unwrap(), alloc_start));
-                current.next = next;
-                return ret;
-            } else {
-                // region not suitable -> continue with next region
-                current = current.next.as_mut().unwrap();
-            }
-        }
-
-        // no suitable region found
-        None
-    }
-
-    /// Try to use the given region for an allocation with given size and alignment.
-    ///
-    /// Returns the allocation start address on success.
-    fn alloc_from_region(region: &ListNode, size: usize, align: usize) -> Result<usize, ()> {
-        let alloc_start = align_up(region.start_addr(), align);
-        let alloc_end = alloc_start.checked_add(size).ok_or(())?;
-
-        if alloc_end > region.end_addr() {
-            // region too small
-            return Err(());
-        }
-
-        let excess_size = region.end_addr() - alloc_end;
-        if excess_size > 0 && excess_size < mem::size_of::<ListNode>() {
-            // rest of region too small to hold a ListNode (required because the
-            // allocation splits the region in a used and a free part)
-            return Err(());
-        }
-
-        // region suitable for allocation
-        Ok(alloc_start)
-    }
-
-    /// Adjust the given layout so that the resulting allocated memory
-    /// region is also capable of storing a `ListNode`.
-    ///
-    /// Returns the adjusted size and alignment as a (size, align) tuple.
-    fn size_align(layout: Layout) -> (usize, usize) {
-        let layout = layout
-            .align_to(mem::align_of::<ListNode>())
-            .expect("adjusting alignment failed")
-            .pad_to_align();
-        let size = layout.size().max(mem::size_of::<ListNode>());
-        (size, layout.align())
-    }
-}
-
-unsafe impl GlobalAlloc for Locked<LinkedListAllocator> {
-    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
-        // perform layout adjustments
-        let (size, align) = LinkedListAllocator::size_align(layout);
-        let mut allocator = self.lock();
-
-        if let Some((region, alloc_start)) = allocator.find_region(size, align) {
-            let alloc_end = alloc_start.checked_add(size).expect("overflow");
-            let excess_size = region.end_addr() - alloc_end;
-            if excess_size > 0 {
-                allocator.add_free_region(alloc_end, excess_size);
-            }
-            alloc_start as *mut u8
-        } else {
-            ptr::null_mut()
-        }
-    }
-
-    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
-        // perform layout adjustments
-        let (size, _) = LinkedListAllocator::size_align(layout);
-
-        self.lock().add_free_region(ptr as usize, size)
-    }
-}

src/driver/keyboard.rs

@@ -1,75 +0,0 @@
-use crate::{print, println, task::interrupt_wake};
-use conquer_once::spin::OnceCell;
-use core::future::Future;
-use core::{
-    pin::Pin,
-    task::{Context, Poll},
-};
-use crossbeam_queue::ArrayQueue;
-use futures_util::task::AtomicWaker;
-use pc_keyboard::{layouts, DecodedKey, HandleControl, Keyboard, ScancodeSet1};
-
-static WAKER: AtomicWaker = AtomicWaker::new();
-static SCANCODE_QUEUE: OnceCell<ArrayQueue<u8>> = OnceCell::uninit();
-
-pub fn init() {
-    SCANCODE_QUEUE
-        .try_init_once(|| ArrayQueue::new(10))
-        .expect("failed to init scancode queue");
-}
-
-/// Called by the keyboard interrupt handler
-///
-/// Must not block (including spinlocks).
-pub(crate) fn keyboard_scancode(scancode: u8) {
-    let scancode_queue = SCANCODE_QUEUE
-        .try_get()
-        .expect("scancode queue not initialized");
-    if let Err(_) = scancode_queue.push(scancode) {
-        println!("WARNING: dropping keyboard input");
-    }
-    if let Some(waker) = WAKER.take() {
-        interrupt_wake(waker);
-    }
-}
-
-fn next_scancode() -> impl Future<Output = u8> {
-    NextScancode
-}
-
-struct NextScancode;
-
-impl Future for NextScancode {
-    type Output = u8;
-
-    fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<u8> {
-        let scancodes = SCANCODE_QUEUE
-            .try_get()
-            .expect("scancode queue not initialized");
-        // fast path
-        if let Ok(scancode) = scancodes.pop() {
-            return Poll::Ready(scancode);
-        }
-
-        WAKER.register(&cx.waker());
-        match scancodes.pop() {
-            Ok(scancode) => Poll::Ready(scancode),
-            Err(crossbeam_queue::PopError) => Poll::Pending,
-        }
-    }
-}
-
-pub async fn keyboard_task() {
-    let mut keyboard = Keyboard::new(layouts::Us104Key, ScancodeSet1, HandleControl::Ignore);
-
-    loop {
-        if let Ok(Some(key_event)) = keyboard.add_byte(next_scancode().await) {
-            if let Some(key) = keyboard.process_keyevent(key_event) {
-                match key {
-                    DecodedKey::Unicode(character) => print!("{}", character),
-                    DecodedKey::RawKey(key) => print!("{:?}", key),
-                }
-            }
-        }
-    }
-}

src/driver/mod.rs

@@ -1,6 +0,0 @@
-pub mod keyboard;
-pub mod timer;
-
-pub fn init() {
-    keyboard::init();
-}

src/driver/timer.rs

@@ -1,55 +0,0 @@
-use crate::{print, task::interrupt_wake};
-use core::future::Future;
-use core::{
-    pin::Pin,
-    sync::atomic::{AtomicU64, Ordering},
-    task::{Context, Poll},
-};
-use futures_util::task::AtomicWaker;
-
-static TICKS: AtomicU64 = AtomicU64::new(0);
-static WAKER: AtomicWaker = AtomicWaker::new();
-
-/// Called by the timer interrupt handler
-///
-/// Must not block (including spinlocks).
-pub(crate) fn tick() {
-    TICKS.fetch_add(1, Ordering::Release);
-    if let Some(waker) = WAKER.take() {
-        interrupt_wake(waker);
-    }
-}
-
-fn next_tick() -> impl Future<Output = u64> {
-    static NEXT_TICK: AtomicU64 = AtomicU64::new(1);
-
-    NextTick {
-        ticks: NEXT_TICK.fetch_add(1, Ordering::Release),
-    }
-}
-
-struct NextTick {
-    ticks: u64,
-}
-
-impl Future for NextTick {
-    type Output = u64;
-
-    fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<u64> {
-        WAKER.register(&cx.waker());
-        let current_ticks = TICKS.load(Ordering::Acquire);
-        if self.ticks < current_ticks {
-            self.ticks += 1;
-            Poll::Ready(self.ticks)
-        } else {
-            Poll::Pending
-        }
-    }
-}
-
-pub async fn timer_task() {
-    loop {
-        next_tick().await;
-        print!(".");
-    }
-}

src/gdt.rs

@@ -10,7 +10,11 @@ lazy_static! {
         let mut tss = TaskStateSegment::new();
         tss.interrupt_stack_table[DOUBLE_FAULT_IST_INDEX as usize] = {
             const STACK_SIZE: usize = 4096;
-            static mut STACK: [u8; STACK_SIZE] = [0; STACK_SIZE];
+
+            #[repr(align(16))]
+            struct Stack([u8; STACK_SIZE]);
+
+            static mut STACK: Stack = Stack([0; STACK_SIZE]);
 
             let stack_start = VirtAddr::from_ptr(unsafe { &STACK });
             let stack_end = stack_start + STACK_SIZE;

src/interrupts.rs

@@ -1,44 +1,16 @@
-use crate::{gdt, hlt_loop, println};
+use crate::{gdt, println};
 use lazy_static::lazy_static;
-use pic8259_simple::ChainedPics;
+use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame};
-use spin;
-use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame, PageFaultErrorCode};
-
-pub const PIC_1_OFFSET: u8 = 32;
-pub const PIC_2_OFFSET: u8 = PIC_1_OFFSET + 8;
-
-#[derive(Debug, Clone, Copy)]
-#[repr(u8)]
-pub enum InterruptIndex {
-    Timer = PIC_1_OFFSET,
-    Keyboard,
-}
-
-impl InterruptIndex {
-    fn as_u8(self) -> u8 {
-        self as u8
-    }
-
-    fn as_usize(self) -> usize {
-        usize::from(self.as_u8())
-    }
-}
-
-pub static PICS: spin::Mutex<ChainedPics> =
-    spin::Mutex::new(unsafe { ChainedPics::new(PIC_1_OFFSET, PIC_2_OFFSET) });
 
 lazy_static! {
     static ref IDT: InterruptDescriptorTable = {
         let mut idt = InterruptDescriptorTable::new();
         idt.breakpoint.set_handler_fn(breakpoint_handler);
-        idt.page_fault.set_handler_fn(page_fault_handler);
         unsafe {
             idt.double_fault
                 .set_handler_fn(double_fault_handler)
                 .set_stack_index(gdt::DOUBLE_FAULT_IST_INDEX);
         }
-        idt[InterruptIndex::Timer.as_usize()].set_handler_fn(timer_interrupt_handler);
-        idt[InterruptIndex::Keyboard.as_usize()].set_handler_fn(keyboard_interrupt_handler);
         idt
     };
 }
@@ -51,19 +23,6 @@ extern "x86-interrupt" fn breakpoint_handler(stack_frame: &mut InterruptStackFra
     println!("EXCEPTION: BREAKPOINT\n{:#?}", stack_frame);
 }
 
-extern "x86-interrupt" fn page_fault_handler(
-    stack_frame: &mut InterruptStackFrame,
-    error_code: PageFaultErrorCode,
-) {
-    use x86_64::registers::control::Cr2;
-
-    println!("EXCEPTION: PAGE FAULT");
-    println!("Accessed Address: {:?}", Cr2::read());
-    println!("Error Code: {:?}", error_code);
-    println!("{:#?}", stack_frame);
-    hlt_loop();
-}
-
 extern "x86-interrupt" fn double_fault_handler(
     stack_frame: &mut InterruptStackFrame,
     _error_code: u64,
@@ -71,28 +30,6 @@ extern "x86-interrupt" fn double_fault_handler(
     panic!("EXCEPTION: DOUBLE FAULT\n{:#?}", stack_frame);
 }
 
-extern "x86-interrupt" fn timer_interrupt_handler(_stack_frame: &mut InterruptStackFrame) {
-    crate::driver::timer::tick();
-
-    unsafe {
-        PICS.lock()
-            .notify_end_of_interrupt(InterruptIndex::Timer.as_u8());
-    }
-}
-
-extern "x86-interrupt" fn keyboard_interrupt_handler(_stack_frame: &mut InterruptStackFrame) {
-    use x86_64::instructions::port::Port;
-    let mut port = Port::new(0x60);
-    let scancode: u8 = unsafe { port.read() };
-
-    crate::driver::keyboard::keyboard_scancode(scancode);
-
-    unsafe {
-        PICS.lock()
-            .notify_end_of_interrupt(InterruptIndex::Keyboard.as_u8());
-    }
-}
-
 #[cfg(test)]
 use crate::{serial_print, serial_println};
 

src/lib.rs

@@ -2,38 +2,19 @@
 #![cfg_attr(test, no_main)]
 #![feature(custom_test_frameworks)]
 #![feature(abi_x86_interrupt)]
-#![feature(alloc_error_handler)]
-#![feature(const_fn)]
-#![feature(alloc_layout_extra)]
-#![feature(wake_trait)]
-#![feature(const_in_array_repeat_expressions)]
-#![feature(type_alias_impl_trait)]
-#![feature(asm)]
 #![test_runner(crate::test_runner)]
 #![reexport_test_harness_main = "test_main"]
 
-extern crate alloc;
-
 use core::panic::PanicInfo;
 
-pub mod allocator;
-pub mod driver;
 pub mod gdt;
 pub mod interrupts;
-pub mod memory;
 pub mod serial;
-pub mod task;
 pub mod vga_buffer;
 
 pub fn init() {
     gdt::init();
     interrupts::init_idt();
-    unsafe { interrupts::PICS.lock().initialize() };
-}
-
-pub fn init_heap_structures() {
-    task::init();
-    driver::init();
 }
 
 pub fn test_runner(tests: &[&dyn Fn()]) {
@@ -48,7 +29,7 @@ pub fn test_panic_handler(info: &PanicInfo) -> ! {
     serial_println!("[failed]\n");
     serial_println!("Error: {}\n", info);
     exit_qemu(QemuExitCode::Failed);
-    hlt_loop();
+    loop {}
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -67,24 +48,13 @@ pub fn exit_qemu(exit_code: QemuExitCode) {
     }
 }
 
-pub fn hlt_loop() -> ! {
-    loop {
-        x86_64::instructions::hlt();
-    }
-}
-
-#[cfg(test)]
-use bootloader::{entry_point, BootInfo};
-
-#[cfg(test)]
-entry_point!(test_kernel_main);
-
 /// Entry point for `cargo xtest`
 #[cfg(test)]
-fn test_kernel_main(_boot_info: &'static BootInfo) -> ! {
+#[no_mangle]
+pub extern "C" fn _start() -> ! {
     init();
     test_main();
-    hlt_loop();
+    loop {}
 }
 
 #[cfg(test)]
@@ -92,8 +62,3 @@ fn test_kernel_main(_boot_info: &'static BootInfo) -> ! {
 fn panic(info: &PanicInfo) -> ! {
     test_panic_handler(info)
 }
-
-#[alloc_error_handler]
-fn alloc_error_handler(layout: alloc::alloc::Layout) -> ! {
-    panic!("allocation error: {:?}", layout)
-}

src/main.rs

@@ -4,72 +4,27 @@
 #![test_runner(blog_os::test_runner)]
 #![reexport_test_harness_main = "test_main"]
 
-extern crate alloc;
-
-use alloc::{boxed::Box, rc::Rc, vec, vec::Vec};
 use blog_os::println;
-use bootloader::{entry_point, BootInfo};
 use core::panic::PanicInfo;
 
-entry_point!(kernel_main);
+#[no_mangle]
-
+pub extern "C" fn _start() -> ! {
-fn kernel_main(boot_info: &'static BootInfo) -> ! {
-    use blog_os::allocator;
-    use blog_os::memory::{self, BootInfoFrameAllocator};
-    use x86_64::VirtAddr;
-
     println!("Hello World{}", "!");
+
     blog_os::init();
 
-    let phys_mem_offset = VirtAddr::new(boot_info.physical_memory_offset);
+    fn stack_overflow() {
-    let mut mapper = unsafe { memory::init(phys_mem_offset) };
+        stack_overflow(); // for each recursion, the return address is pushed
-    let mut frame_allocator = unsafe { BootInfoFrameAllocator::init(&boot_info.memory_map) };
-
-    allocator::init_heap(&mut mapper, &mut frame_allocator).expect("heap initialization failed");
-    blog_os::init_heap_structures();
-
-    // allocate a number on the heap
-    let heap_value = Box::new(41);
-    println!("heap_value at {:p}", heap_value);
-
-    // create a dynamically sized vector
-    let mut vec = Vec::new();
-    for i in 0..500 {
-        vec.push(i);
     }
-    println!("vec at {:p}", vec.as_slice());
 
-    // create a reference counted vector -> will be freed when count reaches 0
+    // uncomment line below to trigger a stack overflow
-    let reference_counted = Rc::new(vec![1, 2, 3]);
+    // stack_overflow();
-    let cloned_reference = reference_counted.clone();
-    println!(
-        "current reference count is {}",
-        Rc::strong_count(&cloned_reference)
-    );
-    core::mem::drop(reference_counted);
-    println!(
-        "reference count is {} now",
-        Rc::strong_count(&cloned_reference)
-    );
 
-    use blog_os::task::executor::Executor;
+    #[cfg(test)]
+    test_main();
 
-    let mut executor = Executor::new();
+    println!("It did not crash!");
-    executor.spawn(bar());
+    loop {}
-
-    executor.spawn(async {
-        #[cfg(test)]
-        test_main();
-    });
-
-    executor.spawn(async {
-        println!("It did not crash!");
-    });
-
-    executor.spawn(blog_os::driver::timer::timer_task());
-    executor.spawn(blog_os::driver::keyboard::keyboard_task());
-
-    executor.run();
 }
 
 /// This function is called on panic.
@@ -77,7 +32,7 @@ fn kernel_main(boot_info: &'static BootInfo) -> ! {
 #[panic_handler]
 fn panic(info: &PanicInfo) -> ! {
     println!("{}", info);
-    blog_os::hlt_loop();
+    loop {}
 }
 
 #[cfg(test)]
@@ -85,15 +40,3 @@ fn panic(info: &PanicInfo) -> ! {
 fn panic(info: &PanicInfo) -> ! {
     blog_os::test_panic_handler(info)
 }
-
-async fn test() -> u32 {
-    42
-}
-
-async fn foo() -> u32 {
-    test().await * 2
-}
-
-async fn bar() {
-    println!("foo result: {}", foo().await);
-}

src/memory.rs

@@ -1,106 +0,0 @@
-use bootloader::bootinfo::{MemoryMap, MemoryRegionType};
-use x86_64::{
-    structures::paging::{
-        FrameAllocator, Mapper, OffsetPageTable, Page, PageTable, PhysFrame, Size4KiB,
-        UnusedPhysFrame,
-    },
-    PhysAddr, VirtAddr,
-};
-
-/// Initialize a new OffsetPageTable.
-///
-/// This function is unsafe because the caller must guarantee that the
-/// complete physical memory is mapped to virtual memory at the passed
-/// `physical_memory_offset`. Also, this function must be only called once
-/// to avoid aliasing `&mut` references (which is undefined behavior).
-pub unsafe fn init(physical_memory_offset: VirtAddr) -> OffsetPageTable<'static> {
-    let level_4_table = active_level_4_table(physical_memory_offset);
-    OffsetPageTable::new(level_4_table, physical_memory_offset)
-}
-
-/// Returns a mutable reference to the active level 4 table.
-///
-/// This function is unsafe because the caller must guarantee that the
-/// complete physical memory is mapped to virtual memory at the passed
-/// `physical_memory_offset`. Also, this function must be only called once
-/// to avoid aliasing `&mut` references (which is undefined behavior).
-unsafe fn active_level_4_table(physical_memory_offset: VirtAddr) -> &'static mut PageTable {
-    use x86_64::registers::control::Cr3;
-
-    let (level_4_table_frame, _) = Cr3::read();
-
-    let phys = level_4_table_frame.start_address();
-    let virt = physical_memory_offset + phys.as_u64();
-    let page_table_ptr: *mut PageTable = virt.as_mut_ptr();
-
-    &mut *page_table_ptr // unsafe
-}
-
-/// Creates an example mapping for the given page to frame `0xb8000`.
-pub fn create_example_mapping(
-    page: Page,
-    mapper: &mut OffsetPageTable,
-    frame_allocator: &mut impl FrameAllocator<Size4KiB>,
-) {
-    use x86_64::structures::paging::PageTableFlags as Flags;
-
-    let frame = PhysFrame::containing_address(PhysAddr::new(0xb8000));
-    // FIXME: ONLY FOR TEMPORARY TESTING
-    let unused_frame = unsafe { UnusedPhysFrame::new(frame) };
-    let flags = Flags::PRESENT | Flags::WRITABLE;
-
-    let map_to_result = mapper.map_to(page, unused_frame, flags, frame_allocator);
-    map_to_result.expect("map_to failed").flush();
-}
-
-/// A FrameAllocator that always returns `None`.
-pub struct EmptyFrameAllocator;
-
-unsafe impl FrameAllocator<Size4KiB> for EmptyFrameAllocator {
-    fn allocate_frame(&mut self) -> Option<UnusedPhysFrame> {
-        None
-    }
-}
-
-/// A FrameAllocator that returns usable frames from the bootloader's memory map.
-pub struct BootInfoFrameAllocator {
-    memory_map: &'static MemoryMap,
-    next: usize,
-}
-
-impl BootInfoFrameAllocator {
-    /// Create a FrameAllocator from the passed memory map.
-    ///
-    /// This function is unsafe because the caller must guarantee that the passed
-    /// memory map is valid. The main requirement is that all frames that are marked
-    /// as `USABLE` in it are really unused.
-    pub unsafe fn init(memory_map: &'static MemoryMap) -> Self {
-        BootInfoFrameAllocator {
-            memory_map,
-            next: 0,
-        }
-    }
-
-    /// Returns an iterator over the usable frames specified in the memory map.
-    fn usable_frames(&self) -> impl Iterator<Item = UnusedPhysFrame> {
-        // get usable regions from memory map
-        let regions = self.memory_map.iter();
-        let usable_regions = regions.filter(|r| r.region_type == MemoryRegionType::Usable);
-        // map each region to its address range
-        let addr_ranges = usable_regions.map(|r| r.range.start_addr()..r.range.end_addr());
-        // transform to an iterator of frame start addresses
-        let frame_addresses = addr_ranges.flat_map(|r| r.step_by(4096));
-        // create `PhysFrame` types from the start addresses
-        let frames = frame_addresses.map(|addr| PhysFrame::containing_address(PhysAddr::new(addr)));
-        // we know that the frames are really unused
-        frames.map(|f| unsafe { UnusedPhysFrame::new(f) })
-    }
-}
-
-unsafe impl FrameAllocator<Size4KiB> for BootInfoFrameAllocator {
-    fn allocate_frame(&mut self) -> Option<UnusedPhysFrame> {
-        let frame = self.usable_frames().nth(self.next);
-        self.next += 1;
-        frame
-    }
-}

src/serial.rs

@@ -13,14 +13,10 @@ lazy_static! {
 #[doc(hidden)]
 pub fn _print(args: ::core::fmt::Arguments) {
     use core::fmt::Write;
-    use x86_64::instructions::interrupts;
+    SERIAL1
-
+        .lock()
-    interrupts::without_interrupts(|| {
+        .write_fmt(args)
-        SERIAL1
+        .expect("Printing to serial failed");
-            .lock()
-            .write_fmt(args)
-            .expect("Printing to serial failed");
-    });
 }
 
 /// Prints to the host through the serial interface.

src/task/executor.rs

@@ -1,127 +0,0 @@
-use super::interrupt_wakeups::interrupt_wakeups;
-use crate::println;
-use alloc::{
-    boxed::Box,
-    collections::{BTreeMap, VecDeque},
-    sync::Arc,
-    task::Wake,
-};
-use core::{
-    future::Future,
-    pin::Pin,
-    task::{Context, Poll},
-};
-use crossbeam_queue::SegQueue;
-
-pub type Task = Pin<Box<dyn Future<Output = ()>>>;
-type TaskId = usize;
-
-pub struct Executor {
-    task_queue: VecDeque<Task>,
-    wake_queue: Arc<SegQueue<TaskId>>,
-    pending_tasks: BTreeMap<TaskId, Task>,
-}
-
-impl Executor {
-    pub fn new() -> Self {
-        Executor {
-            task_queue: VecDeque::new(),
-            wake_queue: Arc::new(SegQueue::new()),
-            pending_tasks: BTreeMap::new(),
-        }
-    }
-
-    pub fn spawn(&mut self, task: impl Future<Output = ()> + 'static) {
-        self.task_queue.push_back(Box::pin(task))
-    }
-
-    pub fn run(&mut self) -> ! {
-        loop {
-            self.run_ready_tasks();
-            self.apply_interrupt_wakeups();
-            self.wake_waiting_tasks();
-            self.hlt_if_idle();
-        }
-    }
-
-    fn run_ready_tasks(&mut self) {
-        while let Some(mut task) = self.task_queue.pop_front() {
-            let waker = self.create_waker(&task).into();
-            let mut context = Context::from_waker(&waker);
-            match task.as_mut().poll(&mut context) {
-                Poll::Ready(()) => {} // task done
-                Poll::Pending => {
-                    // add task to pending_tasks and wait for wakeup
-                    let task_id = Self::task_id(&task);
-                    if self.pending_tasks.insert(task_id, task).is_some() {
-                        panic!("Task with same ID already in pending_tasks");
-                    }
-                }
-            }
-        }
-    }
-
-    /// Invoke wakers for tasks woken by interrupts
-    ///
-    /// The interrupt handlers can't invoke the waker directly since wakers
-    /// might execute arbitrary code, e.g. allocate, which should not be done
-    /// in interrupt handlers to avoid deadlocks.
-    fn apply_interrupt_wakeups(&mut self) {
-        while let Ok(waker) = interrupt_wakeups().pop() {
-            waker.wake();
-        }
-    }
-
-    fn wake_waiting_tasks(&mut self) {
-        while let Ok(task_id) = self.wake_queue.pop() {
-            if let Some(task) = self.pending_tasks.remove(&task_id) {
-                self.task_queue.push_back(task);
-            } else {
-                println!("WARNING: woken task not found in pending_tasks");
-            }
-        }
-    }
-
-    /// Executes the `hlt` instruction if there are no ready tasks
-    fn hlt_if_idle(&self) {
-        if self.task_queue.is_empty() {
-            // disable interrupts to avoid races
-            x86_64::instructions::interrupts::disable();
-            // check if relevant interrupts occured since the last check
-            if interrupt_wakeups().is_empty() {
-                // no interrupts occured -> hlt to wait for next interrupt
-                x86_64::instructions::interrupts::enable_interrupts_and_hlt();
-            } else {
-                // there were some new wakeups -> continue execution
-                x86_64::instructions::interrupts::enable();
-            }
-        }
-    }
-
-    fn task_id(task: &Task) -> TaskId {
-        let future_ref: &dyn Future<Output = ()> = &**task;
-        future_ref as *const _ as *const () as usize
-    }
-
-    fn create_waker(&self, task: &Task) -> Arc<Waker> {
-        Arc::new(Waker {
-            wake_queue: self.wake_queue.clone(),
-            task_id: Self::task_id(task),
-        })
-    }
-}
-
-pub struct Waker {
-    wake_queue: Arc<SegQueue<TaskId>>,
-    task_id: TaskId,
-}
-
-impl Wake for Waker {
-    fn wake(self: Arc<Self>) {
-        self.wake_by_ref();
-    }
-
-    fn wake_by_ref(self: &Arc<Self>) {
-        self.wake_queue.push(self.task_id);
-    }
-}

src/task/interrupt_wakeups.rs

@@ -1,25 +0,0 @@
-use crate::println;
-use conquer_once::spin::OnceCell;
-use core::task::Waker;
-use crossbeam_queue::ArrayQueue;
-
-static INTERRUPT_WAKEUPS: OnceCell<ArrayQueue<Waker>> = OnceCell::uninit();
-
-pub fn init() {
-    INTERRUPT_WAKEUPS
-        .try_init_once(|| ArrayQueue::new(10))
-        .expect("failed to init interrupt wakeup queue");
-}
-
-/// Queues a waker for waking in an interrupt-safe way
-pub(crate) fn interrupt_wake(waker: Waker) {
-    if let Err(_) = interrupt_wakeups().push(waker) {
-        println!("WARNING: dropping interrupt wakeup");
-    }
-}
-
-pub(super) fn interrupt_wakeups() -> &'static ArrayQueue<Waker> {
-    INTERRUPT_WAKEUPS
-        .try_get()
-        .expect("interrupt wakeup queue not initialized")
-}

src/task/mod.rs

@@ -1,8 +0,0 @@
-pub(crate) use interrupt_wakeups::interrupt_wake;
-
-pub mod executor;
-mod interrupt_wakeups;
-
-pub fn init() {
-    interrupt_wakeups::init();
-}

src/vga_buffer.rs

@@ -166,16 +166,11 @@ macro_rules! println {
     ($($arg:tt)*) => ($crate::print!("{}\n", format_args!($($arg)*)));
 }
 
-/// Prints the given formatted string to the VGA text buffer
+/// Prints the given formatted string to the VGA text buffer through the global `WRITER` instance.
-/// through the global `WRITER` instance.
 #[doc(hidden)]
 pub fn _print(args: fmt::Arguments) {
     use core::fmt::Write;
-    use x86_64::instructions::interrupts;
+    WRITER.lock().write_fmt(args).unwrap();
-
-    interrupts::without_interrupts(|| {
-        WRITER.lock().write_fmt(args).unwrap();
-    });
 }
 
 #[test_case]
@@ -196,20 +191,14 @@ fn test_println_many() {
 
 #[test_case]
 fn test_println_output() {
-    use core::fmt::Write;
-    use x86_64::instructions::interrupts;
-
     serial_print!("test_println_output... ");
 
     let s = "Some test string that fits on a single line";
-    interrupts::without_interrupts(|| {
+    println!("{}", s);
-        let mut writer = WRITER.lock();
+    for (i, c) in s.chars().enumerate() {
-        writeln!(writer, "\n{}", s).expect("writeln failed");
+        let screen_char = WRITER.lock().buffer.chars[BUFFER_HEIGHT - 2][i].read();
-        for (i, c) in s.chars().enumerate() {
+        assert_eq!(char::from(screen_char.ascii_character), c);
-            let screen_char = writer.buffer.chars[BUFFER_HEIGHT - 2][i].read();
+    }
-            assert_eq!(char::from(screen_char.ascii_character), c);
-        }
-    });
 
     serial_println!("[ok]");
 }

tests/heap_allocation.rs

@@ -1,76 +0,0 @@
-#![no_std]
-#![no_main]
-#![feature(custom_test_frameworks)]
-#![test_runner(blog_os::test_runner)]
-#![reexport_test_harness_main = "test_main"]
-
-extern crate alloc;
-
-use alloc::{boxed::Box, vec::Vec};
-use blog_os::{allocator::HEAP_SIZE, serial_print, serial_println};
-use bootloader::{entry_point, BootInfo};
-use core::panic::PanicInfo;
-
-entry_point!(main);
-
-fn main(boot_info: &'static BootInfo) -> ! {
-    use blog_os::allocator;
-    use blog_os::memory::{self, BootInfoFrameAllocator};
-    use x86_64::VirtAddr;
-
-    blog_os::init();
-    let phys_mem_offset = VirtAddr::new(boot_info.physical_memory_offset);
-    let mut mapper = unsafe { memory::init(phys_mem_offset) };
-    let mut frame_allocator = unsafe { BootInfoFrameAllocator::init(&boot_info.memory_map) };
-    allocator::init_heap(&mut mapper, &mut frame_allocator).expect("heap initialization failed");
-
-    test_main();
-    loop {}
-}
-
-#[test_case]
-fn simple_allocation() {
-    serial_print!("simple_allocation... ");
-    let heap_value = Box::new(41);
-    assert_eq!(*heap_value, 41);
-    serial_println!("[ok]");
-}
-
-#[test_case]
-fn large_vec() {
-    serial_print!("large_vec... ");
-    let n = 1000;
-    let mut vec = Vec::new();
-    for i in 0..n {
-        vec.push(i);
-    }
-    assert_eq!(vec.iter().sum::<u64>(), (n - 1) * n / 2);
-    serial_println!("[ok]");
-}
-
-#[test_case]
-fn many_boxes() {
-    serial_print!("many_boxes... ");
-    for i in 0..HEAP_SIZE {
-        let x = Box::new(i);
-        assert_eq!(*x, i);
-    }
-    serial_println!("[ok]");
-}
-
-#[test_case]
-fn many_boxes_long_lived() {
-    serial_print!("many_boxes_long_lived... ");
-    let long_lived = Box::new(1); // new
-    for i in 0..HEAP_SIZE {
-        let x = Box::new(i);
-        assert_eq!(*x, i);
-    }
-    assert_eq!(*long_lived, 1); // new
-    serial_println!("[ok]");
-}
-
-#[panic_handler]
-fn panic(info: &PanicInfo) -> ! {
-    blog_os::test_panic_handler(info)
-}