[Rewrite] Architecture Subcrates

Implement architecture-specific subcrates

Author: katietheqt-old

.cargo/config

@@ -1,2 +1,5 @@
+[build]
+target = "i8086-bootloader.json"
+
 [alias]
 xbuild = "build -Zbuild-std=core"

.github/workflows/build.yml

@@ -46,10 +46,9 @@ jobs:
 
     - name: 'Build Bootloader'
       run: cargo xbuild --release
-      working-directory: src/stage_2
 
     - name: 'Convert Bootloader ELF to Binary'
-      run: cargo objcopy -- -I elf64-i386 -O binary --binary-architecture=i386:x86-64 target/x86_64-real_mode/release/stage_2 target/x86_64-real_mode/release/image.bin
+      run: cargo objcopy -- -I elf64-i386 -O binary --binary-architecture=i386:x86-64 target/i8086-bootloader/release/bootloader target/i8086-bootloader/release/image.bin
 
     #  # install QEMU
     # - name: Install QEMU (Linux)

Cargo.lock

@@ -1,18 +1,12 @@
-[workspace]
-members = [
-  "src/shared",
-  "src/v86",
-  "src/bootsector",
-  "src/stage_2",
-  "example-kernel",
-  "test-kernel",
-]
+[package]
+name = "bootloader"
+version = "0.1.0"
+authors = ["Ryland Morgan <[email protected]>"]
+edition = "2018"
+build = "build.rs"
 
-[profile.release]
-opt-level = "z"
-panic = "abort"
-lto = true
+[dependencies]
+shared = { path = "src/shared" }
 
-[profile.release.package.bootsector]
-opt-level = "s"
-codegen-units = 1
+[build-dependencies]
+llvm-tools = "0.1"

Cargo.toml

@@ -0,0 +1,123 @@
+// This build script compiles our bootloader. Because of architecture differences we can't use the standard Rust dependency resolution. To get around this (and add some more seperation between different areas) we compile all of the subcrates as static libraries and link them like we would a C dependency
+
+// TODO - Reuse compilation artifacts so core isn't compiled so many times
+use llvm_tools::{exe, LlvmTools};
+use std::env;
+use std::path::Path;
+use std::process::Command;
+
+fn main() {
+    // Read environment variables set by cargo
+    let out_dir_path = env::var("OUT_DIR").expect("Missing OUT_DIR environment variable");
+    let out_dir = Path::new(&out_dir_path);
+
+    let cargo_path = env::var("CARGO").expect("Missing CARGO environment variable");
+    let cargo = Path::new(&cargo_path);
+
+    let manifest_dir_path =
+        env::var("CARGO_MANIFEST_DIR").expect("Missing CARGO_MANIFEST_DIR environment variable");
+    let manifest_dir = Path::new(&manifest_dir_path);
+
+    // Find the objcopy binary
+    let llvm_tools = LlvmTools::new().expect("LLVM tools not found");
+    let objcopy = llvm_tools
+        .tool(&exe("llvm-objcopy"))
+        .expect("llvm-objcopy not found");
+
+    // Build the bootsector
+    build_subproject(
+        Path::new("src/real/bootsector"),
+        &[
+            "_start",
+            "real_mode_println",
+            "no_int13h_extensions",
+            "dap_load_failed",
+        ],
+        "../i8086-real_mode.json",
+        &out_dir,
+        &objcopy,
+        &cargo,
+    );
+
+    // Build stage 2
+    build_subproject(
+        Path::new("src/real/stage_2"),
+        &["second_stage"],
+        "../i8086-real_mode.json",
+        &out_dir,
+        &objcopy,
+        &cargo,
+    );
+}
+
+fn build_subproject(
+    subproject_dir: &Path,
+    global_symbols: &[&str],
+    target_file_path: &str,
+    root_out_dir: &Path,
+    objcopy: &Path,
+    cargo: &Path,
+) {
+    let subproject_name = subproject_dir
+        .file_stem()
+        .expect("Couldn't get subproject name")
+        .to_str()
+        .expect("Subproject Name is not valid UTF-8");
+    let target_file = Path::new(&target_file_path)
+        .file_stem()
+        .expect("Couldn't get target file stem");
+    let target_dir = root_out_dir.join("target").join(&subproject_name);
+
+    // We have to export at least 1 symbol
+    assert!(
+        global_symbols.len() > 0,
+        "must have at least one global symbol"
+    );
+
+    // Use cargo in CARGO environment variable (set on build)
+    let mut build_cmd = Command::new(cargo);
+
+    // Build inside the subproject
+    build_cmd.current_dir(&subproject_dir);
+
+    // Build in release mode
+    build_cmd.arg("build").arg("--release");
+
+    // Cross-compile core (cargo-xbuild no longer needed)
+    build_cmd.arg("-Zbuild-std=core");
+
+    // Use calculated target directory
+    build_cmd.arg(format!("--target-dir={}", &target_dir.display()));
+
+    // Use the passed target
+    build_cmd.arg("--target").arg(target_file_path);
+
+    // Run the command and make sure it succeeds
+    let build_status = build_cmd.status().expect("Subcrate build failed!");
+    assert!(build_status.success(), "Subcrate build failed!");
+
+    // Compute the path to the binary
+    let binary_dir = target_dir.join(&target_file).join("release");
+    let binary_path = binary_dir.join(format!("lib{}.a", &subproject_name));
+
+    // Use passed objcopy
+    let mut objcopy_cmd = Command::new(objcopy);
+
+    // Localize all symbols except those passed
+    for symbol in global_symbols {
+        objcopy_cmd.arg("-G").arg(symbol);
+    }
+
+    // Pass the binary as argument
+    objcopy_cmd.arg(binary_path);
+
+    // Run the command and make sure it succeeds
+    let objcopy_status = objcopy_cmd.status().expect("Objcopy failed!");
+    assert!(objcopy_status.success(), "Objcopy failed!");
+
+    // Emit flags to the linker
+    //
+    // Staticlibs can't be used as normal dependencies, they have to be linked by a build script
+    println!("cargo:rustc-link-search=native={}", &binary_dir.display());
+    println!("cargo:rustc-link-lib=static={}", &subproject_name);
+}

build.rs

@@ -0,0 +1,26 @@
+{
+	"arch": "x86",
+	"cpu": "i386",
+	"data-layout": "e-m:e-p:32:32-f64:32:64-f80:32-n8:16:32-S128",
+	"dynamic-linking": false,
+	"executables": true,
+	"linker-flavor": "ld.lld",
+	"linker": "rust-lld",
+	"llvm-target": "i386-unknown-none-code16",
+	"max-atomic-width": 64,
+	"position-independent-executables": false,
+	"disable-redzone": true,
+	"target-c-int-width": "32",
+	"target-pointer-width": "32",
+	"target-endian": "little",
+	"panic-strategy": "abort",
+	"os": "none",
+	"vendor": "unknown",
+	"relocation_model": "static",
+	"eliminate_frame_pointer": true,
+	"pre-link-args": {
+		"ld.lld": [
+			"--script=src/real/linker.ld"
+		]
+	}
+}

i8086-bootloader.json

@@ -0,0 +1,7 @@
+#![no_std]
+#![no_main]
+
+mod panic;
+
+#[no_mangle]
+fn bootloader_no_optimize() {}

src/main.rs

@@ -5,5 +5,3 @@ authors = ["Ryland Morgan <[email protected]>"]
 edition = "2018"
 
 [dependencies]
-bitflags = "1.2.1"
-bit_field = "0.10.0"

src/stage_2/src/panic.rs renamed to src/panic.rs

@@ -1,17 +1,13 @@
-#![feature(abi_x86_interrupt)]
-#![feature(const_fn)]
-#![feature(llvm_asm)]
 #![no_std]
+
 // FIXME
 #![allow(dead_code, unused_imports)]
 
 use core::slice;
 
-pub mod gdt;
-pub mod idt;
-
 const EFLAG_IF: u32 = 0x00000200;
 const EFLAG_VM: u32 = 0x00020000;
+
 /*
 pub struct V86 {}