Switch back to official nightly

The Wake trait is based on Arc, which leads to deallocation on wakes. Since interrupts should not (de)allocate, this can lead to a deadlock.

.cargo/config

@@ -0,0 +1,5 @@
+[build]
+target = "x86_64-blog_os.json"
+
+[target.'cfg(target_os = "none")']
+runner = "bootimage runner"

.cargo/config.toml

@@ -1,14 +0,0 @@
-[unstable]
-# TODO: uncomment once https://github.com/rust-lang/cargo/issues/8687 is resolved
-# build-std = ["core", "alloc"]
-
-[build]
-# TODO: uncomment once https://github.com/rust-lang/cargo/issues/8687 is resolved
-# target = "x86_64-blog_os.json"
-
-[target.'cfg(target_os = "none")']
-runner = "cargo run --package disk_image --bin runner --quiet"
-
-[alias]
-xrun = "run --target x86_64-blog_os.json -Zbuild-std=core,alloc"
-bootimage = "run --package disk_image --bin disk_image --quiet"

.github/workflows/build-code.yml

@@ -10,36 +10,11 @@ on:
   schedule:
     - cron: '40 3 * * *'   # every day at 3:40
   pull_request:
-  workflow_dispatch:
 
 jobs:
-  check:
-    name: Check
-    strategy:
-      matrix:
-        platform: [
-          ubuntu-latest,
-          macos-latest,
-          windows-latest
-        ]
-    runs-on: ${{ matrix.platform }}
-    steps:
-      - name: Checkout Repository
-        uses: actions/checkout@v2
-      - name: Install Rust Toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: nightly
-      - name: Install `rust-src` Rustup Component
-        run: rustup component add rust-src
-      - name: Run `cargo check`
-        uses: actions-rs/cargo@v1
-        with:
-          command: check
-
   test:
-    name: Test
+    name: "Test"
+
     strategy:
       matrix:
         platform: [
@@ -47,23 +22,36 @@ jobs:
           macos-latest,
           windows-latest
         ]
+
     runs-on: ${{ matrix.platform }}
+    timeout-minutes: 15
+
     steps:
-      - name: Install Rust Toolchain
+    - name: "Checkout Repository"
-        uses: actions-rs/toolchain@v1
+      uses: actions/checkout@v1
-        with:
+
-          profile: minimal
+    - name: Install Rustup
-          toolchain: nightly
+      run: |
-      - name: Install bootimage
+        curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain nightly
-        run: cargo install bootimage --debug
+        echo ::add-path::$HOME/.cargo/bin
-      - name: Checkout Repository
+      if: runner.os == 'macOS'
-        uses: actions/checkout@v2
+
-      - name: Install Rustup Components
+    - name: "Print Rust Version"
+      run: |
+        rustc -Vv
+        cargo -Vv
+
+    - name: "Install Rustup Components"
       run: rustup component add rust-src llvm-tools-preview
-      - name: Run `cargo bootimage`
+    - name: "Install cargo-xbuild"
-        uses: actions-rs/cargo@v1
+      run: cargo install cargo-xbuild --debug
-        with:
+    - name: "Install bootimage"
-          command: bootimage
+      run: cargo install bootimage --debug
+
+    - name: "Run cargo xbuild"
+      run: cargo xbuild
+    - name: "Create Bootimage"
+      run: cargo bootimage
 
      # install QEMU
     - name: Install QEMU (Linux)
@@ -89,44 +77,20 @@ jobs:
     - name: "Print QEMU Version"
       run: qemu-system-x86_64 --version
 
-      - name: Run `cargo test`
+    - name: "Run cargo xtest"
-        uses: actions-rs/cargo@v1
+      run: cargo xtest
-        with:
-          command: test
 
   check_formatting:
-    name: Check Formatting
+    name: "Check Formatting"
     runs-on: ubuntu-latest
+    timeout-minutes: 2
     steps:
-      - name: Checkout Repository
+    - uses: actions/checkout@v1
-        uses: actions/checkout@v2
+    - name: "Use the latest Rust nightly with rustfmt"
-      - name: Install Rust Toolchain
       uses: actions-rs/toolchain@v1
       with:
-          profile: minimal
           toolchain: nightly
+          profile: minimal
           components: rustfmt
           override: true
-      - name: Run `cargo fmt`
+    - run: cargo fmt -- --check
-        uses: actions-rs/cargo@v1
-        with:
-          command: fmt
-          args: --all -- --check
-
-  clippy:
-    name: Clippy
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout Repository
-        uses: actions/checkout@v2
-      - name: Install Rust Toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: nightly
-          components: clippy, rust-src
-          override: true
-      - name: Run `cargo clippy`
-        uses: actions-rs/cargo@v1
-        with:
-          command: clippy

Cargo.lock

@@ -1,11 +1,5 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-[[package]]
-name = "anyhow"
-version = "1.0.32"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6b602bfe940d21c130f3895acd65221e8a61270debe89d628b9cb4e3ccb8569b"
-
 [[package]]
 name = "autocfg"
 version = "1.0.0"
@@ -30,14 +24,13 @@ version = "0.1.0"
 dependencies = [
  "bootloader",
  "conquer-once",
+ "cooked-waker",
  "crossbeam-queue",
- "font8x8",
  "futures-util",
  "lazy_static",
  "linked_list_allocator",
  "pc-keyboard",
  "pic8259_simple",
- "rlibc",
  "spin",
  "uart_16550",
  "volatile",
@@ -46,16 +39,9 @@ dependencies = [
 
 [[package]]
 name = "bootloader"
-version = "0.9.8"
+version = "0.8.9"
-
-[[package]]
-name = "bootloader-locator"
-version = "0.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "aaaa9db3339d32c2622f2e5d0731eb82a468d3439797c9d4fe426744fe2bd551"
+checksum = "152a28c753e229e037e910b4cd4cd16a90c53dd9a67fd751fa304b4b4a03970c"
-dependencies = [
- "json",
-]
 
 [[package]]
 name = "cfg-if"
@@ -65,9 +51,9 @@ checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
 
 [[package]]
 name = "conquer-once"
-version = "0.2.1"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "96eb12fb69466716fbae9009d389e6a30830ae8975e170eff2d2cff579f9efa3"
+checksum = "6f7644600a548ecad74e4a918392af1798f7dd045be610be3203b9e129b4f98f"
 dependencies = [
  "conquer-util",
 ]
@@ -79,10 +65,31 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "654fb2472cc369d311c547103a1fa81d467bef370ae7a0680f65939895b1182a"
 
 [[package]]
-name = "cpuio"
+name = "cooked-waker"
-version = "0.3.0"
+version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d531514efb06912141fa65967447de805691b685a7565c87d1765afe34a98aa7"
+checksum = "b0032e8be0680b63daf14b0fd7fd57f85fd6897951e110b041d32e839a831914"
+dependencies = [
+ "cooked-waker-derive",
+ "stowaway",
+]
+
+[[package]]
+name = "cooked-waker-derive"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "74ded02b04a8ff53ea7328cd71297cde598bee70d165ad92512bdb7e20be9d74"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "cpuio"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "22b8e308ccfc5acf3b82f79c0eac444cf6114cb2ac67a230ca6c177210068daa"
 
 [[package]]
 name = "crossbeam-queue"
@@ -104,22 +111,6 @@ dependencies = [
  "cfg-if",
 ]
 
-[[package]]
-name = "disk_image"
-version = "0.1.0"
-dependencies = [
- "anyhow",
- "bootloader-locator",
- "locate-cargo-manifest",
- "runner-utils",
-]
-
-[[package]]
-name = "font8x8"
-version = "0.2.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "44226c40489fb1d602344a1d8f1b544570c3435e396dda1eda7b5ef010d8f1be"
-
 [[package]]
 name = "futures-core"
 version = "0.3.4"
@@ -143,12 +134,6 @@ dependencies = [
  "pin-utils",
 ]
 
-[[package]]
-name = "json"
-version = "0.12.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "078e285eafdfb6c4b434e0d31e8cfcb5115b651496faca5749b88fafd4f23bfd"
-
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -158,12 +143,6 @@ dependencies = [
  "spin",
 ]
 
-[[package]]
-name = "libc"
-version = "0.2.76"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "755456fae044e6fa1ebbbd1b3e902ae19e73097ed4ed87bb79934a867c007bc3"
-
 [[package]]
 name = "linked_list_allocator"
 version = "0.8.0"
@@ -173,15 +152,6 @@ dependencies = [
  "spinning_top",
 ]
 
-[[package]]
-name = "locate-cargo-manifest"
-version = "0.2.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "db985b63431fe09e8d71f50aeceffcc31e720cb86be8dad2f38d084c5a328466"
-dependencies = [
- "json",
-]
-
 [[package]]
 name = "lock_api"
 version = "0.3.3"
@@ -199,9 +169,9 @@ checksum = "c48392db76c4e9a69e0b3be356c5f97ebb7b14413c5e4fd0af4755dbf86e2fce"
 
 [[package]]
 name = "pic8259_simple"
-version = "0.2.0"
+version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "af2a5497fb8e59bf8015f67b7dff238d75ef445e03f23edac24ac3a8f09be952"
+checksum = "dc64b2fd10828da8521b6cdabe0679385d7d2a3a6d4c336b819d1fa31ba35c72"
 dependencies = [
  "cpuio",
 ]
@@ -214,38 +184,22 @@ checksum = "5894c618ce612a3fa23881b152b608bafb8c56cfc22f434a3ba3120b40f7b587"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.20"
+version = "1.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "175c513d55719db99da20232b06cda8bab6b83ec2d04e3283edf0213c37c1a29"
+checksum = "6c09721c6781493a2a492a96b5a5bf19b65917fe6728884e7c44dd0c60ca3435"
 dependencies = [
  "unicode-xid",
 ]
 
 [[package]]
 name = "quote"
-version = "1.0.7"
+version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "aa563d17ecb180e500da1cfd2b028310ac758de548efdd203e18f283af693f37"
+checksum = "2bdc6c187c65bca4260c9011c9e3132efe4909da44726bad24cf7572ae338d7f"
 dependencies = [
  "proc-macro2",
 ]
 
-[[package]]
-name = "rlibc"
-version = "1.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fc874b127765f014d792f16763a81245ab80500e2ad921ed4ee9e82481ee08fe"
-
-[[package]]
-name = "runner-utils"
-version = "0.0.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c9dc6848b056990cd51e72aa5556bdbea4a96013e8b18635d183c84159c2988f"
-dependencies = [
- "thiserror",
- "wait-timeout",
-]
-
 [[package]]
 name = "scopeguard"
 version = "1.1.0"
@@ -268,41 +222,27 @@ dependencies = [
 ]
 
 [[package]]
-name = "syn"
+name = "stowaway"
-version = "1.0.40"
+version = "1.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "963f7d3cc59b59b9325165add223142bbf1df27655d07789f109896d353d8350"
+checksum = "32b13d61e782863c0eaeeaf7e8e580dc956a625851fd2fb73e5e92db9601c891"
+
+[[package]]
+name = "syn"
+version = "1.0.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0df0eb663f387145cab623dea85b09c2c5b4b0aef44e945d928e682fce71bb03"
 dependencies = [
  "proc-macro2",
  "quote",
  "unicode-xid",
 ]
 
-[[package]]
-name = "thiserror"
-version = "1.0.20"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7dfdd070ccd8ccb78f4ad66bf1982dc37f620ef696c6b5028fe2ed83dd3d0d08"
-dependencies = [
- "thiserror-impl",
-]
-
-[[package]]
-name = "thiserror-impl"
-version = "1.0.20"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bd80fc12f73063ac132ac92aceea36734f04a1d93c1240c6944e23a3b8841793"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
-]
-
 [[package]]
 name = "uart_16550"
-version = "0.2.7"
+version = "0.2.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e58fc40dc1712664fc9b0a7bd8ca2f21ab49960924fb245a80a05e1e92f3dfe9"
+checksum = "d44b0f30cb82b0fbc15b78ade1064226529ad52028bc8cb8accb98ff6f3d7131"
 dependencies = [
  "bitflags",
  "x86_64",
@@ -310,28 +250,21 @@ dependencies = [
 
 [[package]]
 name = "unicode-xid"
-version = "0.2.1"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f7fe0bb3479651439c9112f72b6c505038574c9fbb575ed1bf3b797fa39dd564"
+checksum = "826e7639553986605ec5979c7dd957c7895e93eabed50ab2ffa7f6128a75097c"
 
 [[package]]
 name = "volatile"
-version = "0.3.0"
+version = "0.2.6"
-
-[[package]]
-name = "wait-timeout"
-version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9f200f5b12eb75f8c1ed65abd4b2db8a6e1b138a20de009dacee265a2498f3f6"
+checksum = "6af0edf5b4faacc31fc51159244d78d65ec580f021afcef7bd53c04aeabc7f29"
-dependencies = [
- "libc",
-]
 
 [[package]]
 name = "x86_64"
-version = "0.11.5"
+version = "0.9.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7c6e9604d08cf91ba0e5cc2175e8cbbdeeb2b8230b818fd9052604c4c5ffd620"
+checksum = "4206b60c9f99766329b66962aa8ddc01df6c7edd02edc046b7a69d5df9fcdbcf"
 dependencies = [
  "bit_field",
  "bitflags",

Cargo.toml

@@ -4,11 +4,6 @@ version = "0.1.0"
 authors = ["Philipp Oppermann <dev@phil-opp.com>"]
 edition = "2018"
 
-[workspace]
-members = [
-    "disk_image",
-]
-
 [[test]]
 name = "should_panic"
 harness = false
@@ -18,16 +13,15 @@ name = "stack_overflow"
 harness = false
 
 [dependencies]
-bootloader = { path = "../../uefi-test"}
+bootloader = { version = "0.8.8", features = ["map_physical_memory"]}
-rlibc = "1.0.0"
+volatile = "0.2.6"
 spin = "0.5.2"
-x86_64 = "0.11.0"
+x86_64 = "0.9.6"
 uart_16550 = "0.2.0"
-pic8259_simple = "0.2.0"
+pic8259_simple = "0.1.1"
 pc-keyboard = "0.5.0"
 linked_list_allocator = "0.8.0"
-volatile = { path= "../../volatile", features = ["unstable"] }
+cooked-waker = "1.0.2"
-font8x8 = { version = "0.2.5", default-features = false, features = ["unicode"]}
 
 [dependencies.lazy_static]
 version = "1.0"
@@ -39,7 +33,7 @@ default-features = false
 features = ["alloc"]
 
 [dependencies.conquer-once]
-version = "0.2.1"
+version = "0.2.0"
 default-features = false
 
 [dependencies.futures-util]
@@ -47,5 +41,9 @@ version = "0.3.4"
 default-features = false
 features = ["alloc"]
 
-[package.metadata.bootloader]
+[package.metadata.bootimage]
-map-physical-memory = true
+test-args = [
+    "-device", "isa-debug-exit,iobase=0xf4,iosize=0x04", "-serial", "stdio",
+    "-display", "none"
+]
+test-success-exit-code = 33         # (0x10 << 1) | 1

README.md

@@ -1,32 +1,28 @@
-# Blog OS (Async/Await)
+# Blog OS (Heap Allocation)
 
-[![Build Status](https://github.com/phil-opp/blog_os/workflows/Build%20Code/badge.svg?branch=post-12)](https://github.com/phil-opp/blog_os/actions?query=workflow%3A%22Build+Code%22+branch%3Apost-12)
+[![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)
 
-This repository contains the source code for the [Async/Await][post] post of the [Writing an OS in Rust](https://os.phil-opp.com) series.
+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.
 
-[post]: https://os.phil-opp.com/async-await/
+[post]: https://os.phil-opp.com/heap-allocation/
 
 **Check out the [master branch](https://github.com/phil-opp/blog_os) for more information.**
 
 ## Building
 
-This project requires a nightly version of Rust because it uses some unstable features. At least nightly _2020-07-15_ is required for building. You might need to run `rustup update nightly --force` to update to the latest nightly even if some components such as `rustfmt` are missing it.
+You need a nightly Rust compiler. First you need to install the `cargo-xbuild` and `bootimage` tools:
-
-You can build the project by running:
 
 ```
-cargo build
+cargo install cargo-xbuild bootimage
 ```
 
-To create a bootable disk image from the compiled kernel, you need to install the [`bootimage`] tool:
+Then you can build the project by running:
-
-[`bootimage`]: https://github.com/rust-osdev/bootimage
 
 ```
-cargo install bootimage
+cargo xbuild
 ```
 
-After installing, you can create the bootable disk image by running:
+To create a bootable disk image, run:
 
 ```
 cargo bootimage
@@ -43,10 +39,10 @@ You can run the disk image in [QEMU] through:
 [QEMU]: https://www.qemu.org/
 
 ```
-cargo run
+cargo xrun
 ```
 
-[QEMU] and the [`bootimage`] tool need to be installed for this.
+Of course [QEMU] needs to be installed for this.
 
 You can also write the image to an USB stick for booting it on a real machine. On Linux, the command for this is:
 

disk_image/Cargo.toml

@@ -1,13 +0,0 @@
-[package]
-name = "disk_image"
-version = "0.1.0"
-authors = ["Philipp Oppermann <dev@phil-opp.com>"]
-edition = "2018"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[dependencies]
-anyhow = "1.0.32"
-bootloader-locator = "0.0.4"
-runner-utils = "0.0.2"
-locate-cargo-manifest = "0.2.0"

disk_image/src/bin/runner.rs

@@ -1,57 +0,0 @@
-use anyhow::anyhow;
-use std::{
-    path::PathBuf,
-    process::{Command, ExitStatus},
-    time::Duration,
-};
-
-const RUN_ARGS: &[&str] = &["-d", "int", "--no-reboot", "-s"];
-const TEST_ARGS: &[&str] = &[
-    "-device",
-    "isa-debug-exit,iobase=0xf4,iosize=0x04",
-    "-serial",
-    "stdio",
-    "-display",
-    "none",
-    "--no-reboot",
-];
-const TEST_TIMEOUT_SECS: u64 = 10;
-
-fn main() -> anyhow::Result<()> {
-    let kernel_binary_path = {
-        let path = PathBuf::from(std::env::args().nth(1).unwrap());
-        path.canonicalize()?
-    };
-
-    let disk_image = disk_image::create_disk_image(&kernel_binary_path, true)?;
-
-    let mut run_cmd = Command::new("qemu-system-x86_64");
-    run_cmd
-        .arg("-drive")
-        .arg(format!("format=raw,file={}", disk_image.display()));
-
-    let binary_kind = runner_utils::binary_kind(&kernel_binary_path);
-    if binary_kind.is_test() {
-        run_cmd.args(TEST_ARGS);
-
-        let exit_status = run_test_command(run_cmd)?;
-        match exit_status.code() {
-            Some(33) => {} // success
-            other => return Err(anyhow!("Test failed (exit code: {:?})", other)),
-        }
-    } else {
-        run_cmd.args(RUN_ARGS);
-
-        let exit_status = run_cmd.status()?;
-        if !exit_status.success() {
-            std::process::exit(exit_status.code().unwrap_or(1));
-        }
-    }
-
-    Ok(())
-}
-
-fn run_test_command(mut cmd: Command) -> anyhow::Result<ExitStatus> {
-    let status = runner_utils::run_with_timeout(&mut cmd, Duration::from_secs(TEST_TIMEOUT_SECS))?;
-    Ok(status)
-}

disk_image/src/lib.rs

@@ -1,45 +0,0 @@
-use anyhow::anyhow;
-use std::{
-    path::{Path, PathBuf},
-    process::Command,
-};
-
-pub fn create_disk_image(kernel_binary_path: &Path, bios_only: bool) -> anyhow::Result<PathBuf> {
-    let bootloader_manifest_path = bootloader_locator::locate_bootloader("bootloader")?;
-    let kernel_manifest_path = locate_cargo_manifest::locate_manifest()?;
-
-    let mut build_cmd = Command::new(env!("CARGO"));
-    build_cmd.current_dir(bootloader_manifest_path.parent().unwrap());
-    build_cmd.arg("builder");
-    build_cmd
-        .arg("--kernel-manifest")
-        .arg(&kernel_manifest_path);
-    build_cmd.arg("--kernel-binary").arg(&kernel_binary_path);
-    build_cmd
-        .arg("--target-dir")
-        .arg(kernel_manifest_path.parent().unwrap().join("target"));
-    build_cmd
-        .arg("--out-dir")
-        .arg(kernel_binary_path.parent().unwrap());
-    build_cmd.arg("--quiet");
-    if bios_only {
-        build_cmd.arg("--firmware").arg("bios");
-    }
-
-    if !build_cmd.status()?.success() {
-        return Err(anyhow!("build failed"));
-    }
-
-    let kernel_binary_name = kernel_binary_path.file_name().unwrap().to_str().unwrap();
-    let disk_image = kernel_binary_path
-        .parent()
-        .unwrap()
-        .join(format!("bootimage-bios-{}.bin", kernel_binary_name));
-    if !disk_image.exists() {
-        return Err(anyhow!(
-            "Disk image does not exist at {} after bootloader build",
-            disk_image.display()
-        ));
-    }
-    Ok(disk_image)
-}

disk_image/src/main.rs

@@ -1,40 +0,0 @@
-use anyhow::anyhow;
-use std::process::Command;
-
-const TARGET_NAME: &str = "x86_64-blog_os";
-const KERNEL_BINARIES: &[&str] = &["blog_os"];
-
-fn main() -> anyhow::Result<()> {
-    // build all binaries
-    let mut build_cmd = Command::new(env!("CARGO"));
-    build_cmd.arg("build");
-    build_cmd.arg("--release");
-    build_cmd.arg("-Zbuild-std=core");
-    build_cmd
-        .arg("--target")
-        .arg(format!("{}.json", TARGET_NAME));
-    if !build_cmd.status()?.success() {
-        return Err(anyhow!("build failed"));
-    };
-
-    let kernel_manifest = locate_cargo_manifest::locate_manifest()?;
-    let target_dir_root = kernel_manifest.parent().unwrap().join("target");
-    let target_dir = target_dir_root.join(TARGET_NAME).join("release");
-
-    for binary_name in KERNEL_BINARIES {
-        let binary_path = {
-            let path = target_dir.join(binary_name);
-            path.canonicalize()?
-        };
-
-        let disk_image = disk_image::create_disk_image(&binary_path, false)?;
-
-        println!(
-            "Created disk image for binary {} at {}",
-            binary_name,
-            disk_image.display()
-        );
-    }
-
-    Ok(())
-}

src/allocator.rs

@@ -35,7 +35,7 @@ pub fn init_heap(
             .allocate_frame()
             .ok_or(MapToError::FrameAllocationFailed)?;
         let flags = PageTableFlags::PRESENT | PageTableFlags::WRITABLE;
-        unsafe { mapper.map_to(page, frame, flags, frame_allocator)?.flush() };
+        mapper.map_to(page, frame, flags, frame_allocator)?.flush();
     }
 
     unsafe {

src/allocator/linked_list.rs

@@ -45,7 +45,7 @@ impl LinkedListAllocator {
     /// 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_eq!(align_up(addr, mem::align_of::<ListNode>()), addr);
+        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

src/framebuffer.rs

@@ -1,179 +0,0 @@
-use bootloader::boot_info::PixelFormat;
-use core::{fmt, slice};
-use font8x8::UnicodeFonts;
-use spin::Mutex;
-use volatile::Volatile;
-
-pub static WRITER: Mutex<Option<Writer>> = Mutex::new(None);
-
-pub fn init(framebuffer: &'static mut bootloader::boot_info::FrameBuffer) {
-    let mut writer = Writer {
-        info: framebuffer.info(),
-        buffer: Volatile::new(framebuffer.buffer()),
-        x_pos: 0,
-        y_pos: 0,
-    };
-    writer.clear();
-
-    // global writer should not be locked here
-    let mut global_writer = WRITER.try_lock().unwrap();
-    assert!(global_writer.is_none(), "Global writer already initialized");
-    *global_writer = Some(writer);
-}
-
-pub struct Writer {
-    buffer: Volatile<&'static mut [u8]>,
-    info: bootloader::boot_info::FrameBufferInfo,
-    x_pos: usize,
-    y_pos: usize,
-}
-
-impl Writer {
-    fn newline(&mut self) {
-        self.y_pos += 8;
-        self.carriage_return();
-    }
-
-    fn carriage_return(&mut self) {
-        self.x_pos = 0;
-    }
-
-    /// Erases all text on the screen
-    pub fn clear(&mut self) {
-        self.x_pos = 0;
-        self.y_pos = 0;
-        self.buffer.fill(0);
-    }
-
-    fn shift_lines_up(&mut self) {
-        let offset = self.info.stride * self.info.bytes_per_pixel * 8;
-        self.buffer.copy_within(offset.., 0);
-        self.y_pos -= 8;
-    }
-
-    fn width(&self) -> usize {
-        self.info.horizontal_resolution
-    }
-
-    fn height(&self) -> usize {
-        self.info.vertical_resolution
-    }
-
-    fn write_char(&mut self, c: char) {
-        match c {
-            '\n' => self.newline(),
-            '\r' => self.carriage_return(),
-            c => {
-                if self.x_pos >= self.width() {
-                    self.newline();
-                }
-                while self.y_pos >= (self.height() - 8) {
-                    self.shift_lines_up();
-                }
-                let rendered = font8x8::BASIC_FONTS
-                    .get(c)
-                    .expect("character not found in basic font");
-                self.write_rendered_char(rendered);
-            }
-        }
-    }
-
-    fn write_rendered_char(&mut self, rendered_char: [u8; 8]) {
-        for (y, byte) in rendered_char.iter().enumerate() {
-            for (x, bit) in (0..8).enumerate() {
-                let on = *byte & (1 << bit) != 0;
-                self.write_pixel(self.x_pos + x, self.y_pos + y, on);
-            }
-        }
-        self.x_pos += 8;
-    }
-
-    fn write_pixel(&mut self, x: usize, y: usize, on: bool) {
-        let pixel_offset = y * self.info.stride + x;
-        let color = if on {
-            match self.info.pixel_format {
-                PixelFormat::RGB => [0x33, 0xff, 0x66, 0],
-                PixelFormat::BGR => [0x66, 0xff, 0x33, 0],
-                _other => [0xff, 0xff, 0xff, 0],
-            }
-        } else {
-            [0, 0, 0, 0]
-        };
-        let bytes_per_pixel = self.info.bytes_per_pixel;
-        let byte_offset = pixel_offset * bytes_per_pixel;
-        self.buffer
-            .index_mut(byte_offset..(byte_offset + bytes_per_pixel))
-            .copy_from_slice(&color[..bytes_per_pixel]);
-    }
-
-    /// Writes the given ASCII string to the buffer.
-    ///
-    /// Wraps lines at `BUFFER_WIDTH`. Supports the `\n` newline character. Does **not**
-    /// support strings with non-ASCII characters, since they can't be printed in the VGA text
-    /// mode.
-    fn write_string(&mut self, s: &str) {
-        for char in s.chars() {
-            self.write_char(char);
-        }
-    }
-}
-
-impl fmt::Write for Writer {
-    fn write_str(&mut self, s: &str) -> fmt::Result {
-        self.write_string(s);
-        Ok(())
-    }
-}
-
-/// Like the `print!` macro in the standard library, but prints to the VGA text buffer.
-#[macro_export]
-macro_rules! print {
-    ($($arg:tt)*) => ($crate::framebuffer::_print(format_args!($($arg)*)));
-}
-
-/// Like the `println!` macro in the standard library, but prints to the VGA text buffer.
-#[macro_export]
-macro_rules! println {
-    () => ($crate::print!("\n"));
-    ($($arg:tt)*) => ($crate::print!("{}\n", format_args!($($arg)*)));
-}
-
-/// Prints the given formatted string to the VGA text buffer
-/// through the global `WRITER` instance.
-#[doc(hidden)]
-pub fn _print(args: fmt::Arguments) {
-    use core::fmt::Write;
-    use x86_64::instructions::interrupts;
-
-    interrupts::without_interrupts(|| {
-        WRITER.lock().as_mut().unwrap().write_fmt(args).unwrap();
-    });
-}
-
-#[test_case]
-fn test_println_simple() {
-    println!("test_println_simple output");
-}
-
-#[test_case]
-fn test_println_many() {
-    for _ in 0..200 {
-        println!("test_println_many output");
-    }
-}
-
-#[test_case]
-fn test_println_output() {
-    use core::fmt::Write;
-    use x86_64::instructions::interrupts;
-
-    let s = "Some test string that fits on a single line";
-    interrupts::without_interrupts(|| {
-        let mut writer = WRITER.lock();
-        writeln!(writer, "\n{}", s).expect("writeln failed");
-        for (i, c) in s.chars().enumerate() {
-            let screen_char = writer.buffer.chars[BUFFER_HEIGHT - 2][i].read();
-            assert_eq!(char::from(screen_char.ascii_character), c);
-        }
-    });
-}

src/gdt.rs

@@ -9,7 +9,7 @@ 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;
+            const STACK_SIZE: usize = 4096;
             static mut STACK: [u8; STACK_SIZE] = [0; STACK_SIZE];
 
             let stack_start = VirtAddr::from_ptr(unsafe { &STACK });

src/interrupts.rs

@@ -92,8 +92,13 @@ extern "x86-interrupt" fn keyboard_interrupt_handler(_stack_frame: &mut Interrup
     }
 }
 
+#[cfg(test)]
+use crate::{serial_print, serial_println};
+
 #[test_case]
 fn test_breakpoint_exception() {
+    serial_print!("test_breakpoint_exception...");
     // invoke a breakpoint exception
     x86_64::instructions::interrupts::int3();
+    serial_println!("[ok]");
 }

src/lib.rs

@@ -4,23 +4,22 @@
 #![feature(abi_x86_interrupt)]
 #![feature(alloc_error_handler)]
 #![feature(const_fn)]
+#![feature(alloc_layout_extra)]
 #![feature(const_in_array_repeat_expressions)]
-#![feature(wake_trait)]
 #![test_runner(crate::test_runner)]
 #![reexport_test_harness_main = "test_main"]
 
 extern crate alloc;
-extern crate rlibc;
 
 use core::panic::PanicInfo;
 
 pub mod allocator;
-pub mod framebuffer;
 pub mod gdt;
 pub mod interrupts;
 pub mod memory;
 pub mod serial;
 pub mod task;
+pub mod vga_buffer;
 
 pub fn init() {
     gdt::init();
@@ -28,25 +27,11 @@ pub fn init() {
     unsafe { interrupts::PICS.lock().initialize() };
     x86_64::instructions::interrupts::enable();
 }
-pub trait Testable {
-    fn run(&self) -> ();
-}
 
-impl<T> Testable for T
+pub fn test_runner(tests: &[&dyn Fn()]) {
-where
-    T: Fn(),
-{
-    fn run(&self) {
-        serial_print!("{}...\t", core::any::type_name::<T>());
-        self();
-        serial_println!("[ok]");
-    }
-}
-
-pub fn test_runner(tests: &[&dyn Testable]) {
     serial_println!("Running {} tests", tests.len());
     for test in tests {
-        test.run();
+        test();
     }
     exit_qemu(QemuExitCode::Success);
 }

src/main.rs

@@ -7,54 +7,38 @@
 extern crate alloc;
 
 use blog_os::println;
-use blog_os::task::{executor::Executor, keyboard, Task};
 use bootloader::{entry_point, BootInfo};
 use core::panic::PanicInfo;
 
 entry_point!(kernel_main);
 
-fn kernel_main(boot_info: &'static mut BootInfo) -> ! {
+fn kernel_main(boot_info: &'static BootInfo) -> ! {
     use blog_os::allocator;
     use blog_os::memory::{self, BootInfoFrameAllocator};
+    use blog_os::task::{keyboard, simple_executor::SimpleExecutor, Task};
     use x86_64::VirtAddr;
 
-    blog_os::framebuffer::init(boot_info.framebuffer.as_mut().unwrap());
-
     println!("Hello World{}", "!");
     blog_os::init();
 
-    let phys_mem_offset = VirtAddr::new(boot_info.physical_memory_offset.unwrap());
+    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_regions) };
+    let mut frame_allocator = unsafe { BootInfoFrameAllocator::init(&boot_info.memory_map) };
 
     allocator::init_heap(&mut mapper, &mut frame_allocator).expect("heap initialization failed");
 
+    let mut executor = SimpleExecutor::new();
+    executor.spawn(Task::new(example_task()));
+    executor.spawn(Task::new(keyboard::print_keypresses()));
+    executor.run();
+
     #[cfg(test)]
     test_main();
 
-    let mut executor = Executor::new();
+    println!("It did not crash!");
-    executor.spawn(Task::new(example_task()));
-    executor.spawn(Task::new(keyboard::print_keypresses()));
-    executor.run();
-}
-
-/// This function is called on panic.
-#[cfg(not(test))]
-#[panic_handler]
-fn panic(info: &PanicInfo) -> ! {
-    unsafe {
-        blog_os::framebuffer::WRITER.force_unlock();
-    };
-    println!("{}", info);
     blog_os::hlt_loop();
 }
 
-#[cfg(test)]
-#[panic_handler]
-fn panic(info: &PanicInfo) -> ! {
-    blog_os::test_panic_handler(info)
-}
-
 async fn async_number() -> u32 {
     42
 }
@@ -64,7 +48,16 @@ async fn example_task() {
     println!("async number: {}", number);
 }
 
-#[test_case]
+/// This function is called on panic.
-fn trivial_assertion() {
+#[cfg(not(test))]
-    assert_eq!(1, 1);
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    println!("{}", info);
+    blog_os::hlt_loop();
+}
+
+#[cfg(test)]
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    blog_os::test_panic_handler(info)
 }

src/memory.rs

@@ -1,7 +1,8 @@
-use bootloader::memory_map::{MemoryRegion, MemoryRegionKind};
+use bootloader::bootinfo::{MemoryMap, MemoryRegionType};
 use x86_64::{
     structures::paging::{
         FrameAllocator, Mapper, OffsetPageTable, Page, PageTable, PhysFrame, Size4KiB,
+        UnusedPhysFrame,
     },
     PhysAddr, VirtAddr,
 };
@@ -44,12 +45,11 @@ pub fn create_example_mapping(
     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 = unsafe {
+    let map_to_result = mapper.map_to(page, unused_frame, flags, frame_allocator);
-        // FIXME: this is not safe, we do it only for testing
-        mapper.map_to(page, frame, flags, frame_allocator)
-    };
     map_to_result.expect("map_to failed").flush();
 }
 
@@ -57,14 +57,14 @@ pub fn create_example_mapping(
 pub struct EmptyFrameAllocator;
 
 unsafe impl FrameAllocator<Size4KiB> for EmptyFrameAllocator {
-    fn allocate_frame(&mut self) -> Option<PhysFrame> {
+    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 [MemoryRegion],
+    memory_map: &'static MemoryMap,
     next: usize,
 }
 
@@ -74,7 +74,7 @@ impl BootInfoFrameAllocator {
     /// 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 [MemoryRegion]) -> Self {
+    pub unsafe fn init(memory_map: &'static MemoryMap) -> Self {
         BootInfoFrameAllocator {
             memory_map,
             next: 0,
@@ -82,21 +82,23 @@ impl BootInfoFrameAllocator {
     }
 
     /// Returns an iterator over the usable frames specified in the memory map.
-    fn usable_frames(&self) -> impl Iterator<Item = PhysFrame> {
+    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.kind == MemoryRegionKind::Usable);
+        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.start..r.end);
+        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
-        frame_addresses.map(|addr| PhysFrame::containing_address(PhysAddr::new(addr)))
+        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<PhysFrame> {
+    fn allocate_frame(&mut self) -> Option<UnusedPhysFrame> {
         let frame = self.usable_frames().nth(self.next);
         self.next += 1;
         frame

src/task/executor.rs

@@ -1,102 +0,0 @@
-use super::{Task, TaskId};
-use alloc::{collections::BTreeMap, sync::Arc, task::Wake};
-use core::task::{Context, Poll, Waker};
-use crossbeam_queue::ArrayQueue;
-
-pub struct Executor {
-    tasks: BTreeMap<TaskId, Task>,
-    task_queue: Arc<ArrayQueue<TaskId>>,
-    waker_cache: BTreeMap<TaskId, Waker>,
-}
-
-impl Executor {
-    pub fn new() -> Self {
-        Executor {
-            tasks: BTreeMap::new(),
-            task_queue: Arc::new(ArrayQueue::new(100)),
-            waker_cache: BTreeMap::new(),
-        }
-    }
-
-    pub fn spawn(&mut self, task: Task) {
-        let task_id = task.id;
-        if self.tasks.insert(task.id, task).is_some() {
-            panic!("task with same ID already in tasks");
-        }
-        self.task_queue.push(task_id).expect("queue full");
-    }
-
-    pub fn run(&mut self) -> ! {
-        loop {
-            self.run_ready_tasks();
-            self.sleep_if_idle();
-        }
-    }
-
-    fn run_ready_tasks(&mut self) {
-        // destructure `self` to avoid borrow checker errors
-        let Self {
-            tasks,
-            task_queue,
-            waker_cache,
-        } = self;
-
-        while let Ok(task_id) = task_queue.pop() {
-            let task = match tasks.get_mut(&task_id) {
-                Some(task) => task,
-                None => continue, // task no longer exists
-            };
-            let waker = waker_cache
-                .entry(task_id)
-                .or_insert_with(|| TaskWaker::new(task_id, task_queue.clone()));
-            let mut context = Context::from_waker(waker);
-            match task.poll(&mut context) {
-                Poll::Ready(()) => {
-                    // task done -> remove it and its cached waker
-                    tasks.remove(&task_id);
-                    waker_cache.remove(&task_id);
-                }
-                Poll::Pending => {}
-            }
-        }
-    }
-
-    fn sleep_if_idle(&self) {
-        use x86_64::instructions::interrupts::{self, enable_interrupts_and_hlt};
-
-        interrupts::disable();
-        if self.task_queue.is_empty() {
-            enable_interrupts_and_hlt();
-        } else {
-            interrupts::enable();
-        }
-    }
-}
-
-struct TaskWaker {
-    task_id: TaskId,
-    task_queue: Arc<ArrayQueue<TaskId>>,
-}
-
-impl TaskWaker {
-    fn new(task_id: TaskId, task_queue: Arc<ArrayQueue<TaskId>>) -> Waker {
-        Waker::from(Arc::new(TaskWaker {
-            task_id,
-            task_queue,
-        }))
-    }
-
-    fn wake_task(&self) {
-        self.task_queue.push(self.task_id).expect("task_queue full");
-    }
-}
-
-impl Wake for TaskWaker {
-    fn wake(self: Arc<Self>) {
-        self.wake_task();
-    }
-
-    fn wake_by_ref(self: &Arc<Self>) {
-        self.wake_task();
-    }
-}

src/task/keyboard.rs

@@ -1,14 +1,13 @@
-use crate::{print, println};
+use crate::print;
+use crate::println;
 use conquer_once::spin::OnceCell;
 use core::{
     pin::Pin,
     task::{Context, Poll},
 };
 use crossbeam_queue::ArrayQueue;
-use futures_util::{
+use futures_util::stream::StreamExt;
-    stream::{Stream, StreamExt},
+use futures_util::{stream::Stream, task::AtomicWaker};
-    task::AtomicWaker,
-};
 use pc_keyboard::{layouts, DecodedKey, HandleControl, Keyboard, ScancodeSet1};
 
 static SCANCODE_QUEUE: OnceCell<ArrayQueue<u8>> = OnceCell::uninit();
@@ -57,10 +56,7 @@ impl Stream for ScancodeStream {
 
         WAKER.register(&cx.waker());
         match queue.pop() {
-            Ok(scancode) => {
+            Ok(scancode) => Poll::Ready(Some(scancode)),
-                WAKER.take();
-                Poll::Ready(Some(scancode))
-            }
             Err(crossbeam_queue::PopError) => Poll::Pending,
         }
     }

src/task/mod.rs

@@ -1,24 +1,17 @@
 use alloc::boxed::Box;
-use core::{
+use core::task::{Context, Poll};
-    future::Future,
+use core::{future::Future, pin::Pin};
-    pin::Pin,
-    sync::atomic::{AtomicU64, Ordering},
-    task::{Context, Poll},
-};
 
-pub mod executor;
 pub mod keyboard;
 pub mod simple_executor;
 
 pub struct Task {
-    id: TaskId,
     future: Pin<Box<dyn Future<Output = ()>>>,
 }
 
 impl Task {
     pub fn new(future: impl Future<Output = ()> + 'static) -> Task {
         Task {
-            id: TaskId::new(),
             future: Box::pin(future),
         }
     }
@@ -26,14 +19,8 @@ impl Task {
     fn poll(&mut self, context: &mut Context) -> Poll<()> {
         self.future.as_mut().poll(context)
     }
-}
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+    fn id(&self) -> usize {
-struct TaskId(u64);
+        &*self.future as *const _ as *const () as usize
-
-impl TaskId {
-    fn new() -> Self {
-        static NEXT_ID: AtomicU64 = AtomicU64::new(0);
-        TaskId(NEXT_ID.fetch_add(1, Ordering::Relaxed))
     }
 }

src/task/simple_executor.rs

@@ -1,15 +1,24 @@
 use super::Task;
-use alloc::collections::VecDeque;
+use alloc::{
-use core::task::{Context, Poll, RawWaker, RawWakerVTable, Waker};
+    collections::{BTreeMap, VecDeque},
+    sync::Arc,
+};
+use cooked_waker::IntoWaker;
+use core::task::{Context, Poll};
+use crossbeam_queue::ArrayQueue;
 
 pub struct SimpleExecutor {
     task_queue: VecDeque<Task>,
+    waiting_tasks: BTreeMap<usize, Task>,
+    wake_queue: Arc<ArrayQueue<usize>>,
 }
 
 impl SimpleExecutor {
     pub fn new() -> SimpleExecutor {
         SimpleExecutor {
             task_queue: VecDeque::new(),
+            waiting_tasks: BTreeMap::new(),
+            wake_queue: Arc::new(ArrayQueue::new(100)),
         }
     }
 
@@ -18,27 +27,60 @@ impl SimpleExecutor {
     }
 
     pub fn run(&mut self) {
+        loop {
+            self.handle_wakeups();
+            self.run_ready_tasks();
+        }
+    }
+
+    fn handle_wakeups(&mut self) {
+        while let Ok(task_id) = self.wake_queue.pop() {
+            if let Some(task) = self.waiting_tasks.remove(&task_id) {
+                self.task_queue.push_back(task);
+            }
+        }
+    }
+
+    fn run_ready_tasks(&mut self) {
         while let Some(mut task) = self.task_queue.pop_front() {
-            let waker = dummy_waker();
+            let waker = TaskWaker {
+                task_id: task.id(),
+                wake_queue: self.wake_queue.clone(),
+            }
+            .into_waker();
             let mut context = Context::from_waker(&waker);
             match task.poll(&mut context) {
                 Poll::Ready(()) => {} // task done
-                Poll::Pending => self.task_queue.push_back(task),
+                Poll::Pending => {
+                    if self.waiting_tasks.insert(task.id(), task).is_some() {
+                        panic!("Same task inserted into waiting_tasks twice");
+                    }
+                }
             }
         }
     }
 }
 
-fn dummy_raw_waker() -> RawWaker {
+#[derive(Debug, Clone, IntoWaker)]
-    fn no_op(_: *const ()) {}
+struct TaskWaker {
-    fn clone(_: *const ()) -> RawWaker {
+    task_id: usize,
-        dummy_raw_waker()
+    wake_queue: Arc<ArrayQueue<usize>>,
 }
 
-    let vtable = &RawWakerVTable::new(clone, no_op, no_op, no_op);
+impl TaskWaker {
-    RawWaker::new(0 as *const (), vtable)
+    fn wake_task(&self) {
+        self.wake_queue.push(self.task_id).expect("wake queue full");
+    }
 }
 
-fn dummy_waker() -> Waker {
+impl cooked_waker::WakeRef for TaskWaker {
-    unsafe { Waker::from_raw(dummy_raw_waker()) }
+    fn wake_by_ref(&self) {
+        self.wake_task();
+    }
+}
+
+impl cooked_waker::Wake for TaskWaker {
+    fn wake(self) {
+        self.wake_task();
+    }
 }

src/vga_buffer.rs

@@ -0,0 +1,215 @@
+use core::fmt;
+use lazy_static::lazy_static;
+use spin::Mutex;
+use volatile::Volatile;
+
+#[cfg(test)]
+use crate::{serial_print, serial_println};
+
+lazy_static! {
+    /// A global `Writer` instance that can be used for printing to the VGA text buffer.
+    ///
+    /// Used by the `print!` and `println!` macros.
+    pub static ref WRITER: Mutex<Writer> = Mutex::new(Writer {
+        column_position: 0,
+        color_code: ColorCode::new(Color::Yellow, Color::Black),
+        buffer: unsafe { &mut *(0xb8000 as *mut Buffer) },
+    });
+}
+
+/// The standard color palette in VGA text mode.
+#[allow(dead_code)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[repr(u8)]
+pub enum Color {
+    Black = 0,
+    Blue = 1,
+    Green = 2,
+    Cyan = 3,
+    Red = 4,
+    Magenta = 5,
+    Brown = 6,
+    LightGray = 7,
+    DarkGray = 8,
+    LightBlue = 9,
+    LightGreen = 10,
+    LightCyan = 11,
+    LightRed = 12,
+    Pink = 13,
+    Yellow = 14,
+    White = 15,
+}
+
+/// A combination of a foreground and a background color.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[repr(transparent)]
+struct ColorCode(u8);
+
+impl ColorCode {
+    /// Create a new `ColorCode` with the given foreground and background colors.
+    fn new(foreground: Color, background: Color) -> ColorCode {
+        ColorCode((background as u8) << 4 | (foreground as u8))
+    }
+}
+
+/// A screen character in the VGA text buffer, consisting of an ASCII character and a `ColorCode`.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[repr(C)]
+struct ScreenChar {
+    ascii_character: u8,
+    color_code: ColorCode,
+}
+
+/// The height of the text buffer (normally 25 lines).
+const BUFFER_HEIGHT: usize = 25;
+/// The width of the text buffer (normally 80 columns).
+const BUFFER_WIDTH: usize = 80;
+
+/// A structure representing the VGA text buffer.
+#[repr(transparent)]
+struct Buffer {
+    chars: [[Volatile<ScreenChar>; BUFFER_WIDTH]; BUFFER_HEIGHT],
+}
+
+/// A writer type that allows writing ASCII bytes and strings to an underlying `Buffer`.
+///
+/// Wraps lines at `BUFFER_WIDTH`. Supports newline characters and implements the
+/// `core::fmt::Write` trait.
+pub struct Writer {
+    column_position: usize,
+    color_code: ColorCode,
+    buffer: &'static mut Buffer,
+}
+
+impl Writer {
+    /// Writes an ASCII byte to the buffer.
+    ///
+    /// Wraps lines at `BUFFER_WIDTH`. Supports the `\n` newline character.
+    pub fn write_byte(&mut self, byte: u8) {
+        match byte {
+            b'\n' => self.new_line(),
+            byte => {
+                if self.column_position >= BUFFER_WIDTH {
+                    self.new_line();
+                }
+
+                let row = BUFFER_HEIGHT - 1;
+                let col = self.column_position;
+
+                let color_code = self.color_code;
+                self.buffer.chars[row][col].write(ScreenChar {
+                    ascii_character: byte,
+                    color_code,
+                });
+                self.column_position += 1;
+            }
+        }
+    }
+
+    /// Writes the given ASCII string to the buffer.
+    ///
+    /// Wraps lines at `BUFFER_WIDTH`. Supports the `\n` newline character. Does **not**
+    /// support strings with non-ASCII characters, since they can't be printed in the VGA text
+    /// mode.
+    fn write_string(&mut self, s: &str) {
+        for byte in s.bytes() {
+            match byte {
+                // printable ASCII byte or newline
+                0x20..=0x7e | b'\n' => self.write_byte(byte),
+                // not part of printable ASCII range
+                _ => self.write_byte(0xfe),
+            }
+        }
+    }
+
+    /// Shifts all lines one line up and clears the last row.
+    fn new_line(&mut self) {
+        for row in 1..BUFFER_HEIGHT {
+            for col in 0..BUFFER_WIDTH {
+                let character = self.buffer.chars[row][col].read();
+                self.buffer.chars[row - 1][col].write(character);
+            }
+        }
+        self.clear_row(BUFFER_HEIGHT - 1);
+        self.column_position = 0;
+    }
+
+    /// Clears a row by overwriting it with blank characters.
+    fn clear_row(&mut self, row: usize) {
+        let blank = ScreenChar {
+            ascii_character: b' ',
+            color_code: self.color_code,
+        };
+        for col in 0..BUFFER_WIDTH {
+            self.buffer.chars[row][col].write(blank);
+        }
+    }
+}
+
+impl fmt::Write for Writer {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        self.write_string(s);
+        Ok(())
+    }
+}
+
+/// Like the `print!` macro in the standard library, but prints to the VGA text buffer.
+#[macro_export]
+macro_rules! print {
+    ($($arg:tt)*) => ($crate::vga_buffer::_print(format_args!($($arg)*)));
+}
+
+/// Like the `println!` macro in the standard library, but prints to the VGA text buffer.
+#[macro_export]
+macro_rules! println {
+    () => ($crate::print!("\n"));
+    ($($arg:tt)*) => ($crate::print!("{}\n", format_args!($($arg)*)));
+}
+
+/// Prints the given formatted string to the VGA text buffer
+/// through the global `WRITER` instance.
+#[doc(hidden)]
+pub fn _print(args: fmt::Arguments) {
+    use core::fmt::Write;
+    use x86_64::instructions::interrupts;
+
+    interrupts::without_interrupts(|| {
+        WRITER.lock().write_fmt(args).unwrap();
+    });
+}
+
+#[test_case]
+fn test_println_simple() {
+    serial_print!("test_println... ");
+    println!("test_println_simple output");
+    serial_println!("[ok]");
+}
+
+#[test_case]
+fn test_println_many() {
+    serial_print!("test_println_many... ");
+    for _ in 0..200 {
+        println!("test_println_many output");
+    }
+    serial_println!("[ok]");
+}
+
+#[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(|| {
+        let mut writer = WRITER.lock();
+        writeln!(writer, "\n{}", s).expect("writeln failed");
+        for (i, c) in s.chars().enumerate() {
+            let screen_char = writer.buffer.chars[BUFFER_HEIGHT - 2][i].read();
+            assert_eq!(char::from(screen_char.ascii_character), c);
+        }
+    });
+
+    serial_println!("[ok]");
+}

tests/basic_boot.rs

@@ -4,7 +4,7 @@
 #![test_runner(blog_os::test_runner)]
 #![reexport_test_harness_main = "test_main"]
 
-use blog_os::println;
+use blog_os::{println, serial_print, serial_println};
 use core::panic::PanicInfo;
 
 #[no_mangle] // don't mangle the name of this function
@@ -21,5 +21,7 @@ fn panic(info: &PanicInfo) -> ! {
 
 #[test_case]
 fn test_println() {
+    serial_print!("test_println... ");
     println!("test_println output");
+    serial_println!("[ok]");
 }

tests/heap_allocation.rs

@@ -7,7 +7,7 @@
 extern crate alloc;
 
 use alloc::{boxed::Box, vec::Vec};
-use blog_os::allocator::HEAP_SIZE;
+use blog_os::{allocator::HEAP_SIZE, serial_print, serial_println};
 use bootloader::{entry_point, BootInfo};
 use core::panic::PanicInfo;
 
@@ -19,9 +19,9 @@ fn main(boot_info: &'static BootInfo) -> ! {
     use x86_64::VirtAddr;
 
     blog_os::init();
-    let phys_mem_offset = VirtAddr::new(boot_info.physical_memory_offset.unwrap());
+    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_regions) };
+    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();
@@ -30,38 +30,44 @@ fn main(boot_info: &'static BootInfo) -> ! {
 
 #[test_case]
 fn simple_allocation() {
-    let heap_value_1 = Box::new(41);
+    serial_print!("simple_allocation... ");
-    let heap_value_2 = Box::new(13);
+    let heap_value = Box::new(41);
-    assert_eq!(*heap_value_1, 41);
+    assert_eq!(*heap_value, 41);
-    assert_eq!(*heap_value_2, 13);
+    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]

tests/should_panic.rs

@@ -13,7 +13,7 @@ pub extern "C" fn _start() -> ! {
 }
 
 fn should_fail() {
-    serial_print!("should_panic::should_fail...\t");
+    serial_print!("should_fail... ");
     assert_eq!(0, 1);
 }
 

tests/stack_overflow.rs

@@ -9,7 +9,7 @@ use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame};
 
 #[no_mangle]
 pub extern "C" fn _start() -> ! {
-    serial_print!("stack_overflow::stack_overflow...\t");
+    serial_print!("stack_overflow... ");
 
     blog_os::gdt::init();
     init_test_idt();
@@ -23,7 +23,6 @@ pub extern "C" fn _start() -> ! {
 #[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! {