[pr] Drift inception

.clang-format

@@ -0,0 +1,33 @@
+# http://clang.llvm.org/docs/ClangFormatStyleOptions.html
+BasedOnStyle: Google
+# This defaults to 'Auto'. Explicitly set it for a while, so that
+# 'vector<vector<int> >' in existing files gets formatted to
+# 'vector<vector<int>>'. ('Auto' means that clang-format will only use
+# 'int>>' if the file already contains at least one such instance.)
+Standard: Cpp11
+SortIncludes: true
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+BreakStringLiterals: false
+DerivePointerAlignment: true
+PointerAlignment: Left
+ColumnLimit: 100
+ForEachMacros: ['list_for_every_entry','list_for_every_entry_safe']
+IncludeBlocks: Regroup
+IncludeCategories:
+  # This specific header must come last in kernel source files.  Its
+  # matching rule must come first so the lower-priority rules don't match.
+  - Regex:           '^<ktl/enforce\.h>'
+    Priority:        1000
+  # C Header: <foo.h>, <net/foo.h>, etc
+  - Regex:           '^(<((zircon/|lib/|fuchsia/|arpa/|net/|netinet/|sys/|fidl/)[a-zA-Z0-9_/\.-]+\.h|[a-zA-Z0-9_-]+\.h)>)'
+    Priority:        1
+  # Cpp Header: <foo> and <experimental/foo>
+  - Regex:           '^(<(experimental/)*[a-zA-Z0-9_-]+>)'
+    Priority:        2
+  # Libraries: <foo/bar.h>
+  - Regex:           '^(<[a-zA-Z0-9_/-]+\.h>)'
+    Priority:        3
+  # Local headers: "foo/bar.h"
+  - Regex:           '^("[.a-zA-Z0-9_/-]+\.h")'
+    Priority:        4

.editorconfig

@@ -0,0 +1,9 @@
+# This file defines indentation style for the Drift tree in a format usable by many editors.
+# For more information on the format and supported editors, see https://editorconfig.org.
+
+[*]
+indent_style = space
+indent_size = 2
+
+[*.{py}]
+indent_size = 4

.gitattributes

@@ -0,0 +1,14 @@
+# Auto detect text files and perform LF normalization.
+*      text=auto
+
+# Always perform LF normalization on these files.
+*.c    text
+*.cc   text
+*.cpp  text
+*.h    text
+*.md   text
+*.zig  text
+
+# Don't treat SVG as text.
+*.svg -diff
+

.github/workflows/ci.yaml

@@ -0,0 +1,41 @@
+name: CI
+on:
+  push:
+    paths-ignore:
+      - "README.md"
+      - "**.md"
+      - "LICENSE**"
+  pull_request:
+    paths-ignore:
+      - "README.md"
+      - "**.md"
+      - "LICENSE**"
+jobs:
+  x86_64-linux:
+    runs-on: ubuntu-latest
+    # We want to run on external PRs, but not on our own internal PRs as they'll be run by the push
+    # to the branch.
+    if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != github.repository
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Setup Zig
+        run: |
+          sudo apt install xz-utils
+          sudo sh -c 'wget -c https://pkg.machengine.org/zig/zig-x86_64-linux-0.14.1.tar.xz -O - | tar -xJ --strip-components=1 -C /usr/local/bin'
+      - name: build
+        run: zig build
+  x86_64-macos:
+    runs-on: macos-13
+    # We want to run on external PRs, but not on our own internal PRs as they'll be run by the push
+    # to the branch.
+    if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != github.repository
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Setup Zig
+        run: |
+          brew install xz
+          sudo sh -c 'wget -c https://pkg.machengine.org/zig/zig-x86_64-macos-0.14.1.tar.xz -O - | tar -xJ --strip-components=1 -C /usr/local/bin'
+      - name: build
+        run: zig build

.gitignore

@@ -0,0 +1,143 @@
+### General file patterns
+*~
+.*.sw?
+.build_lock
+.cargo
+.clangd
+**/.cache/clangd
+.checkstyle
+.classpath
+.config
+.ccls-cache
+.envrc
+.flutter_tool_state
+.cproject
+.DS_Store
+.gdb_history
+.gdbinit
+.jiri_manifest
+.landmines
+.local
+.packages
+.project
+.pydevproject
+.ssh
+.vscode
+.zig-cache
+*_BACKUP_*
+*_REMOTE_*
+*_LOCAL_*
+*_BASE_*
+*.dSYM
+*.fxt
+*.iml
+*.orig
+*.pyc
+*.code-workspace
+!drift.code-workspace
+*.sublime-project
+*.sublime-workspace
+*.swp
+*.swo
+Cargo.lock
+!/third_party/rust_crates/**/Cargo.lock
+Cargo.toml
+!/third_party/rust_crates/**/Cargo.toml
+CMakeLists.txt
+compile_commands.json
+cmake-build-debug/
+cscope.*
+default.profraw
+rls*.log
+Session.vim
+fidl-tags
+tags
+TAGS
+Thumbs.db
+tmp/
+!/third_party/rust_crates/vendor/**/tmp/
+json_generator_tests_*.txt
+tables_generator_tests_*.txt
+
+### fx configuration and cache files.
+# NOTE: For any new files, please write files under the top-level .fx/ directory
+# instead of adding new top-level files, to avoid cluttering this .gitignore
+# file and the top level of local checkouts.
+/.fx/
+!/.fx/config/README.md
+.fx-build-dir
+.fx-metrics-config
+.fx-multi-list
+.fx-remote-config
+.fx-ssh-path
+.fx-sync-from-stem.cache
+
+### Checkout generated files
+/build/cipd.gni
+
+### Infra files
+# These files may exist in a checkout on an Infra VM but not locally
+/.GUARD_FILE
+
+### Directories to be ignored across the tree
+.cipd/
+.idea/
+
+### Top-level directories
+/.jiri/
+/.jiri_root/
+/integration/
+# For storing local scripts and data files in a source tree.
+/local/
+/out/
+/prebuilt/
+/test_data/
+/zig-out/
+
+# Third party repos.
+/third_party/*
+
+/tmp/
+/vendor/
+/build/secondary/third_party/ffmpeg
+/build/secondary/third_party/protobuf
+# Checkouts for some release operations include the infra recipes repository.
+/infra/recipes/
+
+# rust-analyzer
+/rust-project.json
+
+# Generated config for Python analysis
+/pyrightconfig.base.json
+
+# Symlinks related to the Bazel workspace
+/bazel-bin
+/bazel-out
+/bazel-repos
+/bazel-workspace
+
+# Symlinks created by `fx setup-go`.
+/go.mod
+/go.sum
+
+# Running `fx check-licenses` will generate a NOTICE file at the root of the fuchsia repository. The
+# file represents the license state of the entire repository.
+# We automatically run this command during some user/userdebug builds, so it can be included in the
+# Fuchsia images.
+/NOTICE.html
+/NOTICE.html.gz
+
+# Remote build logs
+compiler_info_cache*
+reproxy-gomaip.cache*
+
+# Local test coverage file.
+lcov.info
+.coverage
+
+# Mypy Type Checker extension
+/.mypy_cache
+
+# Nix shell
+/shell.nix
+/default.nix

AUTHORS

@@ -0,0 +1,8 @@
+# This is the list of Drift Authors.
+
+# Names should be added to this file as one of
+#     Organization's name
+#     Individual's name <submission email address>
+#     Individual's name <submission email address> <email2> <emailN>
+
+Mist Tecnologia LTDA.

LICENSE

@@ -0,0 +1,24 @@
+Copyright 2025 The Drift Authors.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

README.md

@@ -1 +1,5 @@
 # drift
+
+## Introduction
+
+Drift is a 64-bit kernel written in Zig.

build.zig

@@ -0,0 +1,19 @@
+//! Copyright 2025 The Drift Authors. All rights reserved.
+//! Use of this source code is governed by a BSD-style license that can be
+//! found in the LICENSE file.
+
+const std = @import("std");
+const Build = std.Build;
+
+const cfg = @import("drift/build_config");
+
+pub fn build(b: *Build) void {
+    const arch = b.option(
+        cfg.BuildConfig.TargetArch,
+        "target_cpu",
+        "Target CPU architecture",
+    ) orelse .x64;
+
+    const slipstream = b.dependency("slipstream", .{ .target_cpu = arch });
+    b.installArtifact(slipstream.artifact("slipstream.elf"));
+}

build.zig.zon

@@ -0,0 +1,14 @@
+.{
+    .name = .drift,
+    .fingerprint = 0x486fc72cc284405b,
+    .version = "0.0.1",
+    .paths = .{""},
+    .dependencies = .{
+        .slipstream = .{
+            .path = "slipstream",
+        },
+        .@"drift/build_config" = .{
+            .path = "build",
+        },
+    },
+}

build/build.zig

@@ -0,0 +1,14 @@
+//! Copyright 2025 The Drift Authors. All rights reserved.
+//! Use of this source code is governed by a BSD-style license that can be
+//! found in the LICENSE file.
+
+const std = @import("std");
+const Build = std.Build;
+
+pub const BuildConfig = @import("config/BuildConfig.zig");
+
+pub fn build(b: *Build) void {
+    _ = b.addModule("build_config", .{
+        .root_source_file = b.path("build.zig"),
+    });
+}

build/config/BuildConfig.zig

@@ -0,0 +1,60 @@
+//! Copyright 2025 The Drift Authors. All rights reserved.
+//! Use of this source code is governed by a BSD-style license that can be
+//! found in the LICENSE file.
+
+const std = @import("std");
+const Build = std.Build;
+const BuildConfig = @This();
+const CompilationMode = @import("CompilationMode.zig");
+
+/// Shared state among all BuildConfig instances.
+build: *Build,
+target_cpu: TargetArch,
+compilation_mode: *CompilationMode,
+
+pub const TargetArch = enum {
+    x64,
+    arm64,
+    riscv64,
+
+    pub fn fromStd(arch: std.Target.Cpu.Arch) @This() {
+        return switch (arch) {
+            .x86_64 => .x64,
+            .aarch64 => .arm64,
+            .riscv64 => .riscv64,
+        };
+    }
+
+    pub fn toStd(self: @This()) std.Target.Cpu.Arch {
+        return switch (self) {
+            .x64 => .x86_64,
+            .arm64 => .aarch64,
+            .riscv64 => .riscv64,
+        };
+    }
+
+    pub fn toStr(self: @This()) []const u8 {
+        return switch (self) {
+            .x64 => "x64",
+            .arm64 => "arm64",
+            .riscv64 => "riscv64",
+        };
+    }
+};
+
+pub fn init(b: *std.Build) error{OutOfMemory}!*BuildConfig {
+    const arena = b.allocator;
+    const bc = try arena.create(BuildConfig);
+
+    bc.* = .{
+        .target_cpu = b.option(
+            TargetArch,
+            "target_cpu",
+            "Target CPU architecture",
+        ) orelse .x64,
+        .build = b,
+        .compilation_mode = try CompilationMode.init(b),
+    };
+
+    return bc;
+}