Rewrite build system

.cargo/config

@@ -0,0 +1,2 @@
+[build]
+target = "x86_64-bootloader.json"

Cargo.toml

@@ -9,6 +9,7 @@ description = "An experimental pure-Rust x86 bootloader."
 repository = "https://github.com/rust-osdev/bootloader"
 publish-lockfile = true
 edition = "2018"
+build = "build.rs"
 
 [dependencies]
 xmas-elf = "0.6.2"
@@ -21,6 +22,9 @@ version = "0.2.4"
 default-features = false
 features = ["unicode"]
 
+[build-dependencies]
+llvm-tools = "0.1"
+
 [features]
 default = []
 vga_320x200 = []

azure-pipelines.yml

@@ -10,8 +10,6 @@ trigger:
     - trying
     # Build pull requests.
     - master
-    # Build post braches
-    - post-*
 
 strategy:
   matrix:
@@ -64,11 +62,11 @@ steps:
   displayName: 'Print Rust Version'
   continueOnError: true
 
-- script: rustup component add rust-src
-  displayName: 'Install Rustup Src Component'
+- script: rustup component add rust-src llvm-tools-preview
+  displayName: 'Install Rustup Components'
 
-- script: cargo install cargo-xbuild bootimage --debug
-  displayName: 'Install cargo-xbuild and bootimage'
+- script: cargo install cargo-xbuild cargo-binutils --debug
+  displayName: 'Install cargo-xbuild cargo-binutils'
 
 - script: sudo apt update && sudo apt install qemu-system-x86
   condition: eq( variables['Agent.OS'], 'Linux' )
@@ -96,20 +94,15 @@ steps:
   workingDirectory: example-kernel
   displayName: 'Build Example Kernel'
 
-- script: cargo run -- --kernel ../example-kernel/target/x86_64-example-kernel/debug/example-kernel
-  workingDirectory: builder
+- script: cargo xbuild --release
   displayName: 'Build Bootloader'
+  env: { KERNEL: "example-kernel/target/x86_64-example-kernel/debug/example-kernel" }
+
+- script: cargo objcopy -- -I elf64-x86-64 -O binary --binary-architecture=i386:x86-64 target/x86_64-bootloader/release/bootloader target/x86_64-bootloader/release/bootloader.bin
+  displayName: 'Convert Bootloader ELF to Binary'
 
 - bash: |
-    qemu-system-x86_64 -drive format=raw,file=target/x86_64-bootloader/release/bootimage.bin -device isa-debug-exit,iobase=0xf4,iosize=0x04 -display none
+    qemu-system-x86_64 -drive format=raw,file=target/x86_64-bootloader/release/bootloader.bin -device isa-debug-exit,iobase=0xf4,iosize=0x04 -display none
     if [ $? -eq 123 ]; then (exit 0); else (exit 1); fi
   displayName: 'Test Bootloader'
 
-- script: cargo run -- --kernel ../example-kernel/target/x86_64-example-kernel/debug/example-kernel --features vga_320x200
-  workingDirectory: builder
-  displayName: 'Build Bootloader (Feature vga_320x200)'
-
-- bash: |
-    qemu-system-x86_64 -drive format=raw,file=target/x86_64-bootloader/release/bootimage.bin -device isa-debug-exit,iobase=0xf4,iosize=0x04 -display none
-    if [ $? -eq 123 ]; then (exit 0); else (exit 1); fi
-  displayName: 'Test Bootloader (Feature vga_320x200)'

build.rs

@@ -0,0 +1,82 @@
+use std::{env, path::{Path, PathBuf}, process::{self, Command}};
+
+fn main() {
+    let target = env::var("TARGET").expect("TARGET not set");
+    if Path::new(&target)
+        .file_stem()
+        .expect("target has no file stem")
+        != "x86_64-bootloader"
+    {
+        return;
+    }
+
+    let out_dir = PathBuf::from(env::var("OUT_DIR").expect("OUT_DIR not set"));
+    let kernel = PathBuf::from(match env::var("KERNEL") {
+        Ok(kernel) => kernel,
+        Err(_) => {
+            eprintln!(
+                "The KERNEL environment variable must be set for building the bootloader."
+            );
+            process::exit(1);
+        }
+    });
+
+    let kernel_file_name = kernel.file_name().expect("KERNEL has no valid file name").to_str().expect("kernel file name not valid utf8");
+    let kernel_file_name_replaced = kernel_file_name.replace('-', "_");
+    let kernel_out_path = out_dir.join(format!("kernel_bin-{}.o", kernel_file_name));
+    let kernel_archive_path = out_dir.join(format!("libkernel_bin-{}.a", kernel_file_name));
+
+    let llvm_tools = match llvm_tools::LlvmTools::new() {
+        Ok(tools) => tools,
+        Err(llvm_tools::Error::NotFound) => {
+            eprintln!("Error: llvm-tools not found");
+            eprintln!("Maybe the rustup component `llvm-tools-preview` is missing?");
+            eprintln!("  Install it through: `rustup component add llvm-tools-preview`");
+            process::exit(1);
+        }
+        Err(err) => {
+            eprintln!("Failed to retrieve llvm-tools component: {:?}", err);
+            process::exit(1);
+        }
+    };
+    let objcopy = llvm_tools.tool(&llvm_tools::exe("llvm-objcopy")).expect("llvm-objcopy not found in llvm-tools");
+
+    let mut cmd = Command::new(objcopy);
+    cmd.arg("-I").arg("binary");
+    cmd.arg("-O").arg("elf64-x86-64");
+    cmd.arg("--binary-architecture=i386:x86-64");
+    cmd.arg("--rename-section").arg(".data=.kernel");
+    cmd.arg("--redefine-sym").arg(format!("_binary_{}_start=_kernel_start_addr", kernel_file_name_replaced));
+    cmd.arg("--redefine-sym").arg(format!("_binary_{}_end=_kernel_end_addr", kernel_file_name_replaced));
+    cmd.arg("--redefine-sym").arg(format!("_binary_{}_size=_kernel_size", kernel_file_name_replaced));
+    cmd.current_dir(kernel.parent().expect("KERNEL has no valid parent dir"));
+    cmd.arg(&kernel_file_name);
+    cmd.arg(&kernel_out_path);
+    let exit_status = cmd.status().expect("failed to run objcopy");
+    if !exit_status.success() {
+        eprintln!("Error: Running objcopy failed");
+        process::exit(1);
+    }
+
+    let ar = llvm_tools.tool(&llvm_tools::exe("llvm-ar")).unwrap_or_else(|| {
+        eprintln!("Failed to retrieve llvm-ar component");
+        eprint!("This component is available since nightly-XXXX-XX-XX,");
+        eprintln!("so try updating your toolchain if you're using an older nightly");
+        process::exit(1);
+    });
+    let mut cmd = Command::new(ar);
+    cmd.arg("crs");
+    cmd.arg(&kernel_archive_path);
+    cmd.arg(&kernel_out_path);
+    let exit_status = cmd.status().expect("failed to run ar");
+    if !exit_status.success() {
+        eprintln!("Error: Running ar failed");
+        process::exit(1);
+    }
+
+    println!("cargo:rerun-if-env-changed=KERNEL");
+    println!("cargo:rerun-if-changed={}", kernel.display());
+    println!("cargo:rerun-if-changed=build.rs");
+    println!("cargo:rustc-link-search=native={}", out_dir.display());
+    println!("cargo:rustc-link-lib=static=kernel_bin-{}", kernel_file_name);
+}

linker.ld

@@ -40,13 +40,11 @@ SECTIONS {
         *(.got)
         . = ALIGN(512);
         _rest_of_bootloader_end_addr = .;
+        __bootloader_end = .;
     }
 
-    _kernel_info_block_start = .;
-    _kib_kernel_size = .;
-    . += 512; /* kernel info block */
-    _kernel_info_block_end = .;
-
-    __bootloader_end = .;
-    _kernel_start_addr = .;
+    .kernel :
+    {
+        KEEP(*(.kernel))
+    }
 }

src/main.rs

@@ -7,6 +7,9 @@
 #![no_std]
 #![no_main]
 
+#[cfg(not(target_os = "none"))]
+compile_error!("The bootloader crate must be compiled for the `x86_64-bootloader.json` target");
+
 use bootloader::bootinfo::{BootInfo, FrameRange};
 use core::panic::PanicInfo;
 use core::{mem, slice};
@@ -63,7 +66,9 @@ impl IdentityMappedAddr {
 extern "C" {
     static mmap_ent: usize;
     static _memory_map: usize;
-    static _kib_kernel_size: usize;
+    static _kernel_start_addr: usize;
+    static _kernel_end_addr: usize;
+    static _kernel_size: usize;
     static __page_table_start: usize;
     static __page_table_end: usize;
     static __bootloader_end: usize;
@@ -77,7 +82,7 @@ pub unsafe extern "C" fn stage_4() -> ! {
           mov ss, bx" ::: "bx" : "intel");
 
     let kernel_start = 0x400000;
-    let kernel_size = _kib_kernel_size as u64;
+    let kernel_size = &_kernel_size as *const _ as u64;
     let memory_map_addr = &_memory_map as *const _ as u64;
     let memory_map_entry_count = (mmap_ent & 0xff) as u64; // Extract lower 8 bits
     let page_table_start = &__page_table_start as *const _ as u64;

src/stage_1.s

@@ -84,7 +84,7 @@ load_rest_of_bootloader_from_disk:
     mov [dap_buffer_addr], ax
 
     # number of disk blocks to load
-    lea ebx, _kernel_info_block_end
+    lea ebx, _rest_of_bootloader_end_addr
     sub ebx, eax # end - start
     shr ebx, 9 # divide by 512 (block size)
     mov [dap_blocks], bx

src/stage_2.s

@@ -50,7 +50,7 @@ load_kernel_from_disk:
     mov edi, 0x400000
 
     # block count
-    mov ecx, _kib_kernel_size
+    lea ecx, _kernel_size
     add ecx, 511 # align up
     shr ecx, 9
 

src/stage_3.s

@@ -52,7 +52,7 @@ set_up_page_tables:
     mov [_p2], eax
     mov eax, (0x400000 | 1 | 2 | (1 << 7))
     mov ecx, 2
-    mov edx, _kib_kernel_size
+    lea edx, _kernel_size
     add edx, 0x400000 # start address
     add edx, 0x200000 - 1 # align up
     shr edx, 12 + 9 # end huge page number