Switch back to official nightly

Use cooked-waker crate for creating wakers
Implement proper wakeups using RawWaker
2025-12-16 14:27:49 +00:00 · 2020-03-22 17:30:00 +01:00 · 2020-03-22 17:24:58 +01:00 · 2020-03-22 16:54:47 +01:00 · 2020-03-22 16:11:25 +01:00 · 2020-03-22 12:45:24 +01:00
25 changed files with 627 additions and 370 deletions
--- a/.cargo/config
+++ b/.cargo/config
@@ -0,0 +1,5 @@
+[build]
+target = "x86_64-blog_os.json"
+
+[target.'cfg(target_os = "none")']
+runner = "bootimage runner"
--- a/.cargo/config.toml
+++ b/.cargo/config.toml
@@ -1,9 +0,0 @@
-[unstable]
-build-std = ["core", "compiler_builtins", "alloc"]
-build-std-features = ["compiler-builtins-mem"]
-
-[build]
-target = "x86_64-blog_os.json"
-
-[target.'cfg(target_os = "none")']
-runner = "bootimage runner"
--- a/.github/workflows/build-code.yml
+++ b/.github/workflows/build-code.yml
@@ -0,0 +1,96 @@
+name: Build Code
+
+on:
+  push:
+    branches:
+      - '*'
+      - '!staging.tmp'
+    tags:
+      - '*'
+  schedule:
+    - cron: '40 3 * * *'   # every day at 3:40
+  pull_request:
+
+jobs:
+  test:
+    name: "Test"
+
+    strategy:
+      matrix:
+        platform: [
+          ubuntu-latest,
+          macos-latest,
+          windows-latest
+        ]
+
+    runs-on: ${{ matrix.platform }}
+    timeout-minutes: 15
+
+    steps:
+    - name: "Checkout Repository"
+      uses: actions/checkout@v1
+
+    - name: Install Rustup
+      run: |
+        curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain nightly
+        echo ::add-path::$HOME/.cargo/bin
+      if: runner.os == 'macOS'
+
+    - name: "Print Rust Version"
+      run: |
+        rustc -Vv
+        cargo -Vv
+
+    - name: "Install Rustup Components"
+      run: rustup component add rust-src llvm-tools-preview
+    - name: "Install cargo-xbuild"
+      run: cargo install cargo-xbuild --debug
+    - name: "Install 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)
+      run: sudo apt update && sudo apt install qemu-system-x86
+      if: runner.os == 'Linux'
+    - name: Install QEMU (macOS)
+      run: brew install qemu
+      if: runner.os == 'macOS'
+      env:
+        HOMEBREW_NO_AUTO_UPDATE: 1
+        HOMEBREW_NO_BOTTLE_SOURCE_FALLBACK: 1
+        HOMEBREW_NO_INSTALL_CLEANUP: 1
+    - name: Install Scoop (Windows)
+      run: |
+        Invoke-Expression (New-Object System.Net.WebClient).DownloadString('https://get.scoop.sh')
+        echo ::add-path::$HOME\scoop\shims
+      if: runner.os == 'Windows'
+      shell: pwsh
+    - name: Install QEMU (Windows)
+      run: scoop install qemu
+      if: runner.os == 'Windows'
+      shell: pwsh
+    - name: "Print QEMU Version"
+      run: qemu-system-x86_64 --version
+
+    - name: "Run cargo xtest"
+      run: cargo xtest
+
+  check_formatting:
+    name: "Check Formatting"
+    runs-on: ubuntu-latest
+    timeout-minutes: 2
+    steps:
+    - uses: actions/checkout@v1
+    - name: "Use the latest Rust nightly with rustfmt"
+      uses: actions-rs/toolchain@v1
+      with:
+          toolchain: nightly
+          profile: minimal
+          components: rustfmt
+          override: true
+    - run: cargo fmt -- --check
--- a/.github/workflows/code.yml
+++ b/.github/workflows/code.yml
@@ -1,130 +0,0 @@
-name: Code
-
-on:
-  push:
-    branches:
-      - '*'
-      - '!staging.tmp'
-    tags:
-      - '*'
-  schedule:
-    - cron: '40 3 * * *'   # every day at 3:40
-  pull_request:
-  workflow_dispatch:
-
-jobs:
-  check:
-    name: Check
-    strategy:
-      fail-fast: false
-      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
-    strategy:
-      fail-fast: false
-      matrix:
-        platform: [
-          ubuntu-latest,
-          macos-latest,
-          windows-latest
-        ]
-    runs-on: ${{ matrix.platform }}
-    steps:
-      - name: Install Rust Toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: nightly
-      - name: Install bootimage
-        run: cargo install bootimage --debug
-      - name: Checkout Repository
-        uses: actions/checkout@v2
-      - name: Install Rustup Components
-        run: rustup component add rust-src llvm-tools-preview
-      - name: Run `cargo bootimage`
-        uses: actions-rs/cargo@v1
-        with:
-          command: bootimage
-
-      # install QEMU
-      - name: Install QEMU (Linux)
-        run: sudo apt update && sudo apt install qemu-system-x86
-        if: runner.os == 'Linux'
-      - name: Install QEMU (macOS)
-        run: brew install qemu
-        if: runner.os == 'macOS'
-        env:
-          HOMEBREW_NO_AUTO_UPDATE: 1
-          HOMEBREW_NO_BOTTLE_SOURCE_FALLBACK: 1
-          HOMEBREW_NO_INSTALL_CLEANUP: 1
-      - name: Install QEMU (Windows)
-        run: |
-          choco install qemu --version 2021.5.5
-          echo "$Env:Programfiles\qemu" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
-        if: runner.os == 'Windows'
-        shell: pwsh
-      - name: "Print QEMU Version"
-        run: qemu-system-x86_64 --version
-
-      - name: Run `cargo test`
-        uses: actions-rs/cargo@v1
-        with:
-          command: test
-
-  check_formatting:
-    name: Check Formatting
-    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: rustfmt
-          override: true
-      - name: Run `cargo fmt`
-        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
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,106 +1,210 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 4
-
 [[package]]
 name = "autocfg"
-version = "1.5.0"
+version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c08606f8c3cbf4ce6ec8e28fb0014a2c086708fe954eaa885384a6165172e7e8"
+checksum = "f8aac770f1885fd7e387acedd76065302551364496e46b3dd00860b2f8359b9d"

 [[package]]
 name = "bit_field"
-version = "0.10.2"
+version = "0.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dc827186963e592360843fb5ba4b973e145841266c1357f7180c43526f2e5b61"
+checksum = "ed8765909f9009617974ab6b7d332625b320b33c326b1e9321382ef1999b5d56"

 [[package]]
 name = "bitflags"
-version = "1.3.2"
+version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
-
-[[package]]
-name = "bitflags"
-version = "2.9.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6a65b545ab31d687cff52899d4890855fec459eb6afe0da6417b8a18da87aa29"
+checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"

 [[package]]
 name = "blog_os"
 version = "0.1.0"
 dependencies = [
 "bootloader",
+ "conquer-once",
+ "cooked-waker",
+ "crossbeam-queue",
+ "futures-util",
 "lazy_static",
 "linked_list_allocator",
 "pc-keyboard",
- "pic8259",
- "spin 0.5.2",
+ "pic8259_simple",
+ "spin",
 "uart_16550",
- "volatile 0.2.7",
+ "volatile",
 "x86_64",
 ]

 [[package]]
 name = "bootloader"
-version = "0.9.32"
+version = "0.8.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1ea119c3ed05625c179e09d17d0914570a3753ca09c890a73d98f6b72aea00d2"
+checksum = "152a28c753e229e037e910b4cd4cd16a90c53dd9a67fd751fa304b4b4a03970c"
+
+[[package]]
+name = "cfg-if"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
+
+[[package]]
+name = "conquer-once"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6f7644600a548ecad74e4a918392af1798f7dd045be610be3203b9e129b4f98f"
+dependencies = [
+ "conquer-util",
+]
+
+[[package]]
+name = "conquer-util"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "654fb2472cc369d311c547103a1fa81d467bef370ae7a0680f65939895b1182a"
+
+[[package]]
+name = "cooked-waker"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+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"
+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]]
 name = "lazy_static"
-version = "1.5.0"
+version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 dependencies = [
- "spin 0.9.8",
+ "spin",
 ]

 [[package]]
 name = "linked_list_allocator"
-version = "0.9.1"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "549ce1740e46b291953c4340adcd74c59bcf4308f4cac050fd33ba91b7168f4a"
+checksum = "18c618c431dfe4419afbe22852f6aceffbc17bd82ba0a18b982def291000824c"
 dependencies = [
 "spinning_top",
 ]

 [[package]]
 name = "lock_api"
-version = "0.4.13"
+version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "96936507f153605bddfcda068dd804796c84324ed2510809e5b2a624c81da765"
+checksum = "79b2de95ecb4691949fea4716ca53cdbcfccb2c612e19644a8bad05edcf9f47b"
 dependencies = [
- "autocfg",
 "scopeguard",
 ]

 [[package]]
 name = "pc-keyboard"
-version = "0.7.0"
+version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ed089a1fbffe3337a1a345501c981f1eb1e47e69de5a40e852433e12953c3174"
+checksum = "c48392db76c4e9a69e0b3be356c5f97ebb7b14413c5e4fd0af4755dbf86e2fce"

 [[package]]
-name = "pic8259"
-version = "0.10.4"
+name = "pic8259_simple"
+version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cb844b5b01db1e0b17938685738f113bfc903846f18932b378bc0eabfa40e194"
+checksum = "dc64b2fd10828da8521b6cdabe0679385d7d2a3a6d4c336b819d1fa31ba35c72"
 dependencies = [
- "x86_64",
+ "cpuio",
 ]

 [[package]]
-name = "rustversion"
-version = "1.0.22"
+name = "pin-utils"
+version = "0.1.0-alpha.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b39cdef0fa800fc44525c84ccb54a029961a8215f9619753635a9c0d2538d46d"
+checksum = "5894c618ce612a3fa23881b152b608bafb8c56cfc22f434a3ba3120b40f7b587"
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c09721c6781493a2a492a96b5a5bf19b65917fe6728884e7c44dd0c60ca3435"
+dependencies = [
+ "unicode-xid",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2bdc6c187c65bca4260c9011c9e3132efe4909da44726bad24cf7572ae338d7f"
+dependencies = [
+ "proc-macro2",
+]

 [[package]]
 name = "scopeguard"
-version = "1.2.0"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
+checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"

 [[package]]
 name = "spin"
@@ -108,52 +212,60 @@ version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6e63cff320ae2c57904679ba7cb63280a3dc4613885beafb148ee7bf9aa9042d"

-[[package]]
-name = "spin"
-version = "0.9.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
-
 [[package]]
 name = "spinning_top"
-version = "0.2.5"
+version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5b9eb1a2f4c41445a3a0ff9abc5221c5fcd28e1f13cd7c0397706f9ac938ddb0"
+checksum = "32d801a3a53bcf5071f85fef8d5cab9e5f638fc5580a37e6eb7aba4b37438d24"
 dependencies = [
 "lock_api",
 ]

 [[package]]
-name = "uart_16550"
-version = "0.2.19"
+name = "stowaway"
+version = "1.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "614ff2a87880d4bd4374722268598a970bbad05ced8bf630439417347254ab2e"
+checksum = "32b13d61e782863c0eaeeaf7e8e580dc956a625851fd2fb73e5e92db9601c891"
+
+[[package]]
+name = "syn"
+version = "1.0.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0df0eb663f387145cab623dea85b09c2c5b4b0aef44e945d928e682fce71bb03"
 dependencies = [
- "bitflags 1.3.2",
- "rustversion",
+ "proc-macro2",
+ "quote",
+ "unicode-xid",
+]
+
+[[package]]
+name = "uart_16550"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d44b0f30cb82b0fbc15b78ade1064226529ad52028bc8cb8accb98ff6f3d7131"
+dependencies = [
+ "bitflags",
 "x86_64",
 ]

 [[package]]
-name = "volatile"
-version = "0.2.7"
+name = "unicode-xid"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f6b06ad3ed06fef1713569d547cdbdb439eafed76341820fb0e0344f29a41945"
+checksum = "826e7639553986605ec5979c7dd957c7895e93eabed50ab2ffa7f6128a75097c"

 [[package]]
 name = "volatile"
-version = "0.4.6"
+version = "0.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "442887c63f2c839b346c192d047a7c87e73d0689c9157b00b53dcc27dd5ea793"
+checksum = "6af0edf5b4faacc31fc51159244d78d65ec580f021afcef7bd53c04aeabc7f29"

 [[package]]
 name = "x86_64"
-version = "0.14.13"
+version = "0.9.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c101112411baafbb4bf8d33e4c4a80ab5b02d74d2612331c61e8192fc9710491"
+checksum = "4206b60c9f99766329b66962aa8ddc01df6c7edd02edc046b7a69d5df9fcdbcf"
 dependencies = [
 "bit_field",
- "bitflags 2.9.2",
- "rustversion",
- "volatile 0.4.6",
+ "bitflags",
 ]
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,7 +2,7 @@
 name = "blog_os"
 version = "0.1.0"
 authors = ["Philipp Oppermann <dev@phil-opp.com>"]
-edition = "2024"
+edition = "2018"

 [[test]]
 name = "should_panic"
@@ -13,32 +13,37 @@ name = "stack_overflow"
 harness = false

 [dependencies]
-bootloader = { version = "0.9", features = ["map_physical_memory"] }
+bootloader = { version = "0.8.8", features = ["map_physical_memory"]}
 volatile = "0.2.6"
 spin = "0.5.2"
-x86_64 = "0.14.2"
+x86_64 = "0.9.6"
 uart_16550 = "0.2.0"
-pic8259 = "0.10.1"
-pc-keyboard = "0.7.0"
-linked_list_allocator = "0.9.0"
+pic8259_simple = "0.1.1"
+pc-keyboard = "0.5.0"
+linked_list_allocator = "0.8.0"
+cooked-waker = "1.0.2"

 [dependencies.lazy_static]
 version = "1.0"
 features = ["spin_no_std"]

-[[bin]]
-name = "blog_os"
-test = true
-bench = false
+[dependencies.crossbeam-queue]
+version = "0.2.1"
+default-features = false
+features = ["alloc"]

+[dependencies.conquer-once]
+version = "0.2.0"
+default-features = false
+
+[dependencies.futures-util]
+version = "0.3.4"
+default-features = false
+features = ["alloc"]

 [package.metadata.bootimage]
 test-args = [
-    "-device",
-    "isa-debug-exit,iobase=0xf4,iosize=0x04",
-    "-serial",
-    "stdio",
-    "-display",
-    "none",
+    "-device", "isa-debug-exit,iobase=0xf4,iosize=0x04", "-serial", "stdio",
+    "-display", "none"
 ]
-test-success-exit-code = 33 # (0x10 << 1) | 1
+test-success-exit-code = 33         # (0x10 << 1) | 1
--- a/README.md
+++ b/README.md
@@ -1,32 +1,28 @@
-# Blog OS (Allocator Designs)
+# Blog OS (Heap Allocation)

-[![Build Status](https://github.com/phil-opp/blog_os/workflows/Code/badge.svg?branch=post-11)](https://github.com/phil-opp/blog_os/actions?query=workflow%3A%22Code%22+branch%3Apost-11)
+[![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 [Allocator Designs][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/allocator-designs/
+[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 can build the project by running:
+You need a nightly Rust compiler. First you need to install the `cargo-xbuild` and `bootimage` tools:

 ```
-cargo build
+cargo install cargo-xbuild bootimage
 ```

-To create a bootable disk image from the compiled kernel, you need to install the [`bootimage`] tool:
-
-[`bootimage`]: https://github.com/rust-osdev/bootimage
+Then you can build the project by running:

 ```
-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:

--- a/src/allocator.rs
+++ b/src/allocator.rs
@@ -2,10 +2,10 @@ use alloc::alloc::{GlobalAlloc, Layout};
 use core::ptr::null_mut;
 use fixed_size_block::FixedSizeBlockAllocator;
 use x86_64::{
-    VirtAddr,
    structures::paging::{
-        FrameAllocator, Mapper, Page, PageTableFlags, Size4KiB, mapper::MapToError,
+        mapper::MapToError, FrameAllocator, Mapper, Page, PageTableFlags, Size4KiB,
    },
+    VirtAddr,
 };

 pub mod bump;
@@ -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 {
--- a/src/allocator/bump.rs
+++ b/src/allocator/bump.rs
@@ -1,4 +1,4 @@
-use super::{Locked, align_up};
+use super::{align_up, Locked};
 use alloc::alloc::{GlobalAlloc, Layout};
 use core::ptr;

--- a/src/allocator/fixed_size_block.rs
+++ b/src/allocator/fixed_size_block.rs
@@ -31,9 +31,8 @@ pub struct FixedSizeBlockAllocator {
 impl FixedSizeBlockAllocator {
    /// Creates an empty FixedSizeBlockAllocator.
    pub const fn new() -> Self {
-        const EMPTY: Option<&'static mut ListNode> = None;
        FixedSizeBlockAllocator {
-            list_heads: [EMPTY; BLOCK_SIZES.len()],
+            list_heads: [None; BLOCK_SIZES.len()],
            fallback_allocator: linked_list_allocator::Heap::empty(),
        }
    }
@@ -44,9 +43,7 @@ impl FixedSizeBlockAllocator {
    /// 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) {
-        unsafe {
-            self.fallback_allocator.init(heap_start, heap_size);
-        }
+        self.fallback_allocator.init(heap_start, heap_size);
    }

    /// Allocates using the fallback allocator.
@@ -93,16 +90,12 @@ unsafe impl GlobalAlloc for Locked<FixedSizeBlockAllocator> {
                assert!(mem::size_of::<ListNode>() <= BLOCK_SIZES[index]);
                assert!(mem::align_of::<ListNode>() <= BLOCK_SIZES[index]);
                let new_node_ptr = ptr as *mut ListNode;
-                unsafe {
-                    new_node_ptr.write(new_node);
-                    allocator.list_heads[index] = Some(&mut *new_node_ptr);
-                }
+                new_node_ptr.write(new_node);
+                allocator.list_heads[index] = Some(&mut *new_node_ptr);
            }
            None => {
                let ptr = NonNull::new(ptr).unwrap();
-                unsafe {
-                    allocator.fallback_allocator.deallocate(ptr, layout);
-                }
+                allocator.fallback_allocator.deallocate(ptr, layout);
            }
        }
    }
--- a/src/allocator/linked_list.rs
+++ b/src/allocator/linked_list.rs
@@ -1,4 +1,4 @@
-use super::{Locked, align_up};
+use super::{align_up, Locked};
 use alloc::alloc::{GlobalAlloc, Layout};
 use core::{mem, ptr};

@@ -39,25 +39,21 @@ impl LinkedListAllocator {
    /// 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) {
-        unsafe {
-            self.add_free_region(heap_start, heap_size);
-        }
+        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_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
        let mut node = ListNode::new(size);
        node.next = self.head.next.take();
        let node_ptr = addr as *mut ListNode;
-        unsafe {
-            node_ptr.write(node);
-            self.head.next = Some(&mut *node_ptr);
-        }
+        node_ptr.write(node);
+        self.head.next = Some(&mut *node_ptr)
    }

    /// Looks for a free region with the given size and alignment and removes
@@ -132,9 +128,7 @@ unsafe impl GlobalAlloc for Locked<LinkedListAllocator> {
            let alloc_end = alloc_start.checked_add(size).expect("overflow");
            let excess_size = region.end_addr() - alloc_end;
            if excess_size > 0 {
-                unsafe {
-                    allocator.add_free_region(alloc_end, excess_size);
-                }
+                allocator.add_free_region(alloc_end, excess_size);
            }
            alloc_start as *mut u8
        } else {
@@ -146,6 +140,6 @@ unsafe impl GlobalAlloc for Locked<LinkedListAllocator> {
        // perform layout adjustments
        let (size, _) = LinkedListAllocator::size_align(layout);

-        unsafe { self.lock().add_free_region(ptr as usize, size) }
+        self.lock().add_free_region(ptr as usize, size)
    }
 }
--- a/src/gdt.rs
+++ b/src/gdt.rs
@@ -1,7 +1,7 @@
 use lazy_static::lazy_static;
-use x86_64::VirtAddr;
 use x86_64::structures::gdt::{Descriptor, GlobalDescriptorTable, SegmentSelector};
 use x86_64::structures::tss::TaskStateSegment;
+use x86_64::VirtAddr;

 pub const DOUBLE_FAULT_IST_INDEX: u16 = 0;

@@ -9,10 +9,10 @@ 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(&raw const STACK);
+            let stack_start = VirtAddr::from_ptr(unsafe { &STACK });
            let stack_end = stack_start + STACK_SIZE;
            stack_end
        };
@@ -41,12 +41,12 @@ struct Selectors {
 }

 pub fn init() {
-    use x86_64::instructions::segmentation::{CS, Segment};
+    use x86_64::instructions::segmentation::set_cs;
    use x86_64::instructions::tables::load_tss;

    GDT.0.load();
    unsafe {
-        CS::set_reg(GDT.1.code_selector);
+        set_cs(GDT.1.code_selector);
        load_tss(GDT.1.tss_selector);
    }
 }
--- a/src/interrupts.rs
+++ b/src/interrupts.rs
@@ -1,6 +1,6 @@
 use crate::{gdt, hlt_loop, print, println};
 use lazy_static::lazy_static;
-use pic8259::ChainedPics;
+use pic8259_simple::ChainedPics;
 use spin;
 use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame, PageFaultErrorCode};

@@ -47,12 +47,12 @@ pub fn init_idt() {
    IDT.load();
 }

-extern "x86-interrupt" fn breakpoint_handler(stack_frame: InterruptStackFrame) {
+extern "x86-interrupt" fn breakpoint_handler(stack_frame: &mut InterruptStackFrame) {
    println!("EXCEPTION: BREAKPOINT\n{:#?}", stack_frame);
 }

 extern "x86-interrupt" fn page_fault_handler(
-    stack_frame: InterruptStackFrame,
+    stack_frame: &mut InterruptStackFrame,
    error_code: PageFaultErrorCode,
 ) {
    use x86_64::registers::control::Cr2;
@@ -65,13 +65,13 @@ extern "x86-interrupt" fn page_fault_handler(
 }

 extern "x86-interrupt" fn double_fault_handler(
-    stack_frame: InterruptStackFrame,
+    stack_frame: &mut InterruptStackFrame,
    _error_code: u64,
 ) -> ! {
    panic!("EXCEPTION: DOUBLE FAULT\n{:#?}", stack_frame);
 }

-extern "x86-interrupt" fn timer_interrupt_handler(_stack_frame: InterruptStackFrame) {
+extern "x86-interrupt" fn timer_interrupt_handler(_stack_frame: &mut InterruptStackFrame) {
    print!(".");
    unsafe {
        PICS.lock()
@@ -79,32 +79,12 @@ extern "x86-interrupt" fn timer_interrupt_handler(_stack_frame: InterruptStackFr
    }
 }

-extern "x86-interrupt" fn keyboard_interrupt_handler(_stack_frame: InterruptStackFrame) {
-    use pc_keyboard::{DecodedKey, HandleControl, Keyboard, ScancodeSet1, layouts};
-    use spin::Mutex;
+extern "x86-interrupt" fn keyboard_interrupt_handler(_stack_frame: &mut InterruptStackFrame) {
    use x86_64::instructions::port::Port;

-    lazy_static! {
-        static ref KEYBOARD: Mutex<Keyboard<layouts::Us104Key, ScancodeSet1>> =
-            Mutex::new(Keyboard::new(
-                ScancodeSet1::new(),
-                layouts::Us104Key,
-                HandleControl::Ignore
-            ));
-    }
-
-    let mut keyboard = KEYBOARD.lock();
    let mut port = Port::new(0x60);
-
    let scancode: u8 = unsafe { port.read() };
-    if let Ok(Some(key_event)) = keyboard.add_byte(scancode) {
-        if let Some(key) = keyboard.process_keyevent(key_event) {
-            match key {
-                DecodedKey::Unicode(character) => print!("{}", character),
-                DecodedKey::RawKey(key) => print!("{:?}", key),
-            }
-        }
-    }
+    crate::task::keyboard::add_scancode(scancode);

    unsafe {
        PICS.lock()
@@ -112,8 +92,13 @@ extern "x86-interrupt" fn keyboard_interrupt_handler(_stack_frame: InterruptStac
    }
 }

+#[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]");
 }
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2,10 +2,15 @@
 #![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(const_in_array_repeat_expressions)]
 #![test_runner(crate::test_runner)]
 #![reexport_test_harness_main = "test_main"]

 extern crate alloc;
+
 use core::panic::PanicInfo;

 pub mod allocator;
@@ -13,6 +18,7 @@ pub mod gdt;
 pub mod interrupts;
 pub mod memory;
 pub mod serial;
+pub mod task;
 pub mod vga_buffer;

 pub fn init() {
@@ -21,25 +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
-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]) {
+pub fn test_runner(tests: &[&dyn Fn()]) {
    serial_println!("Running {} tests", tests.len());
    for test in tests {
-        test.run();
+        test();
    }
    exit_qemu(QemuExitCode::Success);
 }
@@ -74,7 +66,7 @@ pub fn hlt_loop() -> ! {
 }

 #[cfg(test)]
-use bootloader::{BootInfo, entry_point};
+use bootloader::{entry_point, BootInfo};

 #[cfg(test)]
 entry_point!(test_kernel_main);
@@ -92,3 +84,8 @@ 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)
+}
--- a/src/main.rs
+++ b/src/main.rs
@@ -6,9 +6,8 @@

 extern crate alloc;

-use alloc::{boxed::Box, rc::Rc, vec, vec::Vec};
 use blog_os::println;
-use bootloader::{BootInfo, entry_point};
+use bootloader::{entry_point, BootInfo};
 use core::panic::PanicInfo;

 entry_point!(kernel_main);
@@ -16,6 +15,7 @@ entry_point!(kernel_main);
 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;

    println!("Hello World{}", "!");
@@ -27,29 +27,10 @@ fn kernel_main(boot_info: &'static BootInfo) -> ! {

    allocator::init_heap(&mut mapper, &mut frame_allocator).expect("heap initialization failed");

-    // 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
-    let reference_counted = Rc::new(vec![1, 2, 3]);
-    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)
-    );
+    let mut executor = SimpleExecutor::new();
+    executor.spawn(Task::new(example_task()));
+    executor.spawn(Task::new(keyboard::print_keypresses()));
+    executor.run();

    #[cfg(test)]
    test_main();
@@ -58,6 +39,15 @@ fn kernel_main(boot_info: &'static BootInfo) -> ! {
    blog_os::hlt_loop();
 }

+async fn async_number() -> u32 {
+    42
+}
+
+async fn example_task() {
+    let number = async_number().await;
+    println!("async number: {}", number);
+}
+
 /// This function is called on panic.
 #[cfg(not(test))]
 #[panic_handler]
@@ -71,8 +61,3 @@ fn panic(info: &PanicInfo) -> ! {
 fn panic(info: &PanicInfo) -> ! {
    blog_os::test_panic_handler(info)
 }
-
-#[test_case]
-fn trivial_assertion() {
-    assert_eq!(1, 1);
-}
--- a/src/memory.rs
+++ b/src/memory.rs
@@ -1,7 +1,10 @@
 use bootloader::bootinfo::{MemoryMap, MemoryRegionType};
 use x86_64::{
+    structures::paging::{
+        FrameAllocator, Mapper, OffsetPageTable, Page, PageTable, PhysFrame, Size4KiB,
+        UnusedPhysFrame,
+    },
    PhysAddr, VirtAddr,
-    structures::paging::{FrameAllocator, OffsetPageTable, PageTable, PhysFrame, Size4KiB},
 };

 /// Initialize a new OffsetPageTable.
@@ -11,10 +14,8 @@ use x86_64::{
 /// `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> {
-    unsafe {
-        let level_4_table = active_level_4_table(physical_memory_offset);
-        OffsetPageTable::new(level_4_table, physical_memory_offset)
-    }
+    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.
@@ -32,14 +33,31 @@ unsafe fn active_level_4_table(physical_memory_offset: VirtAddr) -> &'static mut
    let virt = physical_memory_offset + phys.as_u64();
    let page_table_ptr: *mut PageTable = virt.as_mut_ptr();

-    unsafe { &mut *page_table_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<PhysFrame> {
+    fn allocate_frame(&mut self) -> Option<UnusedPhysFrame> {
        None
    }
 }
@@ -64,7 +82,7 @@ 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.region_type == MemoryRegionType::Usable);
@@ -73,12 +91,14 @@ impl BootInfoFrameAllocator {
        // 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
--- a/src/task/keyboard.rs
+++ b/src/task/keyboard.rs
@@ -0,0 +1,79 @@
+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::stream::StreamExt;
+use futures_util::{stream::Stream, task::AtomicWaker};
+use pc_keyboard::{layouts, DecodedKey, HandleControl, Keyboard, ScancodeSet1};
+
+static SCANCODE_QUEUE: OnceCell<ArrayQueue<u8>> = OnceCell::uninit();
+static WAKER: AtomicWaker = AtomicWaker::new();
+
+/// Called by the keyboard interrupt handler
+///
+/// Must not block or allocate.
+pub(crate) fn add_scancode(scancode: u8) {
+    if let Ok(queue) = SCANCODE_QUEUE.try_get() {
+        if let Err(_) = queue.push(scancode) {
+            println!("WARNING: scancode queue full; dropping keyboard input");
+        } else {
+            WAKER.wake();
+        }
+    } else {
+        println!("WARNING: scancode queue uninitialized");
+    }
+}
+
+pub struct ScancodeStream {
+    _private: (),
+}
+
+impl ScancodeStream {
+    pub fn new() -> Self {
+        SCANCODE_QUEUE
+            .try_init_once(|| ArrayQueue::new(100))
+            .expect("ScancodeStream::new should only be called once");
+        ScancodeStream { _private: () }
+    }
+}
+
+impl Stream for ScancodeStream {
+    type Item = u8;
+
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<u8>> {
+        let queue = SCANCODE_QUEUE
+            .try_get()
+            .expect("scancode queue not initialized");
+
+        // fast path
+        if let Ok(scancode) = queue.pop() {
+            return Poll::Ready(Some(scancode));
+        }
+
+        WAKER.register(&cx.waker());
+        match queue.pop() {
+            Ok(scancode) => Poll::Ready(Some(scancode)),
+            Err(crossbeam_queue::PopError) => Poll::Pending,
+        }
+    }
+}
+
+pub async fn print_keypresses() {
+    let mut scancodes = ScancodeStream::new();
+    let mut keyboard = Keyboard::new(layouts::Us104Key, ScancodeSet1, HandleControl::Ignore);
+
+    while let Some(scancode) = scancodes.next().await {
+        if let Ok(Some(key_event)) = keyboard.add_byte(scancode) {
+            if let Some(key) = keyboard.process_keyevent(key_event) {
+                match key {
+                    DecodedKey::Unicode(character) => print!("{}", character),
+                    DecodedKey::RawKey(key) => print!("{:?}", key),
+                }
+            }
+        }
+    }
+}
--- a/src/task/mod.rs
+++ b/src/task/mod.rs
@@ -0,0 +1,26 @@
+use alloc::boxed::Box;
+use core::task::{Context, Poll};
+use core::{future::Future, pin::Pin};
+
+pub mod keyboard;
+pub mod simple_executor;
+
+pub struct Task {
+    future: Pin<Box<dyn Future<Output = ()>>>,
+}
+
+impl Task {
+    pub fn new(future: impl Future<Output = ()> + 'static) -> Task {
+        Task {
+            future: Box::pin(future),
+        }
+    }
+
+    fn poll(&mut self, context: &mut Context) -> Poll<()> {
+        self.future.as_mut().poll(context)
+    }
+
+    fn id(&self) -> usize {
+        &*self.future as *const _ as *const () as usize
+    }
+}
--- a/src/task/simple_executor.rs
+++ b/src/task/simple_executor.rs
@@ -0,0 +1,86 @@
+use super::Task;
+use alloc::{
+    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)),
+        }
+    }
+
+    pub fn spawn(&mut self, task: Task) {
+        self.task_queue.push_back(task)
+    }
+
+    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 = 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 => {
+                    if self.waiting_tasks.insert(task.id(), task).is_some() {
+                        panic!("Same task inserted into waiting_tasks twice");
+                    }
+                }
+            }
+        }
+    }
+}
+
+#[derive(Debug, Clone, IntoWaker)]
+struct TaskWaker {
+    task_id: usize,
+    wake_queue: Arc<ArrayQueue<usize>>,
+}
+
+impl TaskWaker {
+    fn wake_task(&self) {
+        self.wake_queue.push(self.task_id).expect("wake queue full");
+    }
+}
+
+impl cooked_waker::WakeRef for TaskWaker {
+    fn wake_by_ref(&self) {
+        self.wake_task();
+    }
+}
+
+impl cooked_waker::Wake for TaskWaker {
+    fn wake(self) {
+        self.wake_task();
+    }
+}
--- a/src/vga_buffer.rs
+++ b/src/vga_buffer.rs
@@ -3,6 +3,9 @@ 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.
    ///
@@ -177,14 +180,18 @@ pub fn _print(args: fmt::Arguments) {

 #[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]
@@ -192,6 +199,8 @@ 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();
@@ -201,4 +210,6 @@ fn test_println_output() {
            assert_eq!(char::from(screen_char.ascii_character), c);
        }
    });
+
+    serial_println!("[ok]");
 }
--- a/tests/basic_boot.rs
+++ b/tests/basic_boot.rs
@@ -4,10 +4,10 @@
 #![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;

-#[unsafe(no_mangle)] // don't mangle the name of this function
+#[no_mangle] // don't mangle the name of this function
 pub extern "C" fn _start() -> ! {
    test_main();

@@ -21,5 +21,7 @@ fn panic(info: &PanicInfo) -> ! {

 #[test_case]
 fn test_println() {
+    serial_print!("test_println... ");
    println!("test_println output");
+    serial_println!("[ok]");
 }
--- a/tests/heap_allocation.rs
+++ b/tests/heap_allocation.rs
@@ -7,8 +7,8 @@
 extern crate alloc;

 use alloc::{boxed::Box, vec::Vec};
-use blog_os::allocator::HEAP_SIZE;
-use bootloader::{BootInfo, entry_point};
+use blog_os::{allocator::HEAP_SIZE, serial_print, serial_println};
+use bootloader::{entry_point, BootInfo};
 use core::panic::PanicInfo;

 entry_point!(main);
@@ -30,38 +30,44 @@ fn main(boot_info: &'static BootInfo) -> ! {

 #[test_case]
 fn simple_allocation() {
-    let heap_value_1 = Box::new(41);
-    let heap_value_2 = Box::new(13);
-    assert_eq!(*heap_value_1, 41);
-    assert_eq!(*heap_value_2, 13);
+    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]
--- a/tests/should_panic.rs
+++ b/tests/should_panic.rs
@@ -1,10 +1,10 @@
 #![no_std]
 #![no_main]

-use blog_os::{QemuExitCode, exit_qemu, serial_print, serial_println};
+use blog_os::{exit_qemu, serial_print, serial_println, QemuExitCode};
 use core::panic::PanicInfo;

-#[unsafe(no_mangle)]
+#[no_mangle]
 pub extern "C" fn _start() -> ! {
    should_fail();
    serial_println!("[test did not panic]");
@@ -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);
 }

--- a/tests/stack_overflow.rs
+++ b/tests/stack_overflow.rs
@@ -2,14 +2,14 @@
 #![no_main]
 #![feature(abi_x86_interrupt)]

-use blog_os::{QemuExitCode, exit_qemu, serial_print, serial_println};
+use blog_os::{exit_qemu, serial_print, serial_println, QemuExitCode};
 use core::panic::PanicInfo;
 use lazy_static::lazy_static;
 use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame};

-#[unsafe(no_mangle)]
+#[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! {
@@ -44,7 +43,7 @@ pub fn init_test_idt() {
 }

 extern "x86-interrupt" fn test_double_fault_handler(
-    _stack_frame: InterruptStackFrame,
+    _stack_frame: &mut InterruptStackFrame,
    _error_code: u64,
 ) -> ! {
    serial_println!("[ok]");
--- a/x86_64-blog_os.json
+++ b/x86_64-blog_os.json
@@ -1,16 +1,15 @@
 {
    "llvm-target": "x86_64-unknown-none",
-    "data-layout": "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128",
+    "data-layout": "e-m:e-i64:64-f80:128-n8:16:32:64-S128",
    "arch": "x86_64",
    "target-endian": "little",
    "target-pointer-width": "64",
-    "target-c-int-width": 32,
+    "target-c-int-width": "32",
    "os": "none",
    "executables": true,
    "linker-flavor": "ld.lld",
    "linker": "rust-lld",
    "panic-strategy": "abort",
    "disable-redzone": true,
-    "features": "-mmx,-sse,+soft-float",
-    "rustc-abi": "x86-softfloat"
+    "features": "-mmx,-sse,+soft-float"
  }
Author	SHA1	Message	Date
Philipp Oppermann	d21a78dc0b	Switch back to official nightly	2020-03-22 17:30:00 +01:00
Philipp Oppermann	0186f65ece	Use cooked-waker crate for creating wakers	2020-03-22 17:24:58 +01:00
Philipp Oppermann	2772abc8eb	Implement proper wakeups using RawWaker	2020-03-22 16:54:47 +01:00
Philipp Oppermann	51f90236a5	Base dummy waker on RawWaker to avoid allocations 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.	2020-03-22 16:11:25 +01:00
Philipp Oppermann	90abd5c8c5	Add a keyboard task that prints keypresses	2020-03-22 12:45:24 +01:00
Philipp Oppermann	a6273614e4	Add waker support to ScancodeStream	2020-03-22 12:16:17 +01:00
Philipp Oppermann	3a2a468a0b	Add a ScancodeStream based on the SCANCODE_QUEUE	2020-03-22 12:12:11 +01:00
Philipp Oppermann	05f6abd261	Fill the scancode queue on keyboard interrupts	2020-03-22 12:11:09 +01:00
Philipp Oppermann	255982a8b7	Implement scancode queue	2020-03-20 13:03:41 +01:00
Philipp Oppermann	f885f17b70	Implement a simple poll-loop executor	2020-03-19 16:46:37 +01:00