Include payload as bytes in EFI stub

osdk/src/commands/build/bin.rs

@@ -1,14 +1,14 @@
 // SPDX-License-Identifier: MPL-2.0
 
 use std::{
-    fs::OpenOptions,
-    io::{Seek, SeekFrom, Write},
+    fs::{File, OpenOptions},
+    io::{Read, Seek, SeekFrom, Write},
     path::{Path, PathBuf},
     process::Command,
 };
 
 use linux_bzimage_builder::{
-    legacy32_rust_target_json, make_bzimage, BzImageType, PayloadEncoding,
+    encode_kernel, legacy32_rust_target_json, make_bzimage, BzImageType, PayloadEncoding,
 };
 
 use crate::{
@@ -42,13 +42,21 @@ pub fn make_install_bzimage(
                 let gen_target_json_path = target_dir.as_ref().join("x86_64-i386_pm-none.json");
                 std::fs::write(&gen_target_json_path, target_json).unwrap();
                 let arch = SetupInstallArch::Other(gen_target_json_path.canonicalize().unwrap());
-                install_setup_with_arch(setup_install_dir, setup_target_dir, &arch);
+                install_setup_with_arch(
+                    setup_install_dir,
+                    setup_target_dir,
+                    &arch,
+                    aster_elf,
+                    encoding,
+                );
             }
             BzImageType::Efi64 => {
                 install_setup_with_arch(
                     setup_install_dir,
                     setup_target_dir,
                     &SetupInstallArch::X86_64,
+                    aster_elf,
+                    encoding,
                 );
             }
         };
@@ -58,13 +66,7 @@ pub fn make_install_bzimage(
     let install_path = install_dir.as_ref().join(target_name);
     info!("Building bzImage");
     println!("install_path: {:?}", install_path);
-    make_bzimage(
-        &install_path,
-        image_type,
-        aster_elf.path(),
-        &setup_bin,
-        encoding,
-    );
+    make_bzimage(&install_path, image_type, &setup_bin);
 
     AsterBin::new(
         &install_path,
@@ -160,6 +162,8 @@ fn install_setup_with_arch(
     install_dir: impl AsRef<Path>,
     target_dir: impl AsRef<Path>,
     arch: &SetupInstallArch,
+    aster_elf: &AsterBin,
+    encoding: PayloadEncoding,
 ) {
     if !target_dir.as_ref().exists() {
         std::fs::create_dir_all(&target_dir).unwrap();
@@ -198,6 +202,7 @@ fn install_setup_with_arch(
     };
     rustflags.push(target_feature_args);
     cmd.env("RUSTFLAGS", rustflags.join(" "));
+    cmd.env("PAYLOAD_FILE", encode_kernel_to_file(aster_elf, encoding));
     cmd.arg("install").arg("linux-bzimage-setup");
     cmd.arg("--force");
     cmd.arg("--root").arg(install_dir.as_ref());
@@ -226,3 +231,26 @@ fn install_setup_with_arch(
         );
     }
 }
+
+fn encode_kernel_to_file(aster_elf: &AsterBin, encoding: PayloadEncoding) -> PathBuf {
+    let kernel_path = aster_elf.path();
+    let encoded_path = {
+        let mut filename = kernel_path.file_name().unwrap().to_os_string();
+        filename.push(".compressed");
+        kernel_path.with_file_name(filename)
+    };
+
+    let mut kernel = Vec::new();
+    File::open(kernel_path)
+        .unwrap()
+        .read_to_end(&mut kernel)
+        .unwrap();
+
+    let encoded = encode_kernel(kernel, encoding);
+    File::create(&encoded_path)
+        .unwrap()
+        .write_all(&encoded)
+        .unwrap();
+
+    encoded_path
+}

ostd/libs/linux-bzimage/builder/src/lib.rs

@@ -23,8 +23,7 @@ use std::{
     path::Path,
 };
 
-use encoder::encode_kernel;
-pub use encoder::PayloadEncoding;
+pub use encoder::{encode_kernel, PayloadEncoding};
 use mapping::{SetupFileOffset, SetupVA};
 use xmas_elf::program::SegmentData;
 
@@ -41,17 +40,9 @@ pub enum BzImageType {
 /// Explanations for the arguments:
 ///  - `target_image_path`: The path to the target bzImage;
 ///  - `image_type`: The type of the bzImage that we are building;
-///  - `kernel_path`: The path to the kernel ELF;
 ///  - `setup_elf_path`: The path to the setup ELF;
-///  - `encoding`: The encoding format for compressing the kernel ELF.
 ///
-pub fn make_bzimage(
-    target_image_path: &Path,
-    image_type: BzImageType,
-    kernel_path: &Path,
-    setup_elf_path: &Path,
-    encoding: PayloadEncoding,
-) {
+pub fn make_bzimage(target_image_path: &Path, image_type: BzImageType, setup_elf_path: &Path) {
     let mut setup_elf = Vec::new();
     File::open(setup_elf_path)
         .unwrap()
@@ -61,32 +52,14 @@ pub fn make_bzimage(
     // Pad the header with 8-byte alignment.
     setup.resize((setup.len() + 7) & !7, 0x00);
 
-    let mut kernel = Vec::new();
-    File::open(kernel_path)
-        .unwrap()
-        .read_to_end(&mut kernel)
-        .unwrap();
-    let payload = match image_type {
-        BzImageType::Legacy32 => kernel,
-        BzImageType::Efi64 => encode_kernel(kernel, encoding),
-    };
-
-    let setup_len = setup.len();
-    let payload_len = payload.len();
-    let payload_offset = SetupFileOffset::from(setup_len);
-    fill_legacy_header_fields(&mut setup, payload_len, setup_len, payload_offset.into());
-
     let mut kernel_image = File::create(target_image_path).unwrap();
     kernel_image.write_all(&setup).unwrap();
-    kernel_image.write_all(&payload).unwrap();
-
-    let image_size = setup_len + payload_len;
 
     if matches!(image_type, BzImageType::Efi64) {
         // Write the PE/COFF header to the start of the file.
         // Since the Linux boot header starts at 0x1f1, we can write the PE/COFF header directly to the
         // start of the file without overwriting the Linux boot header.
-        let pe_header = pe_header::make_pe_coff_header(&setup_elf, image_size);
+        let pe_header = pe_header::make_pe_coff_header(&setup_elf, setup.len());
         assert!(
             pe_header.header_at_zero.len() <= 0x1f1,
             "PE/COFF header is too large"
@@ -141,44 +114,3 @@ fn to_flat_binary(elf_file: &[u8]) -> Vec<u8> {
 
     bin
 }
-
-/// This function should be used when generating the Linux x86 Boot setup header.
-/// Some fields in the Linux x86 Boot setup header should be filled after assembled.
-/// And the filled fields must have the bytes with values of 0xAB. See
-/// `ostd/src/arch/x86/boot/linux_boot/setup/src/header.S` for more
-/// info on this mechanism.
-fn fill_header_field(header: &mut [u8], offset: usize, value: &[u8]) {
-    let size = value.len();
-    assert_eq!(
-        &header[offset..offset + size],
-        vec![0xABu8; size].as_slice(),
-        "The field {:#x} to be filled must be marked with 0xAB",
-        offset
-    );
-    header[offset..offset + size].copy_from_slice(value);
-}
-
-fn fill_legacy_header_fields(
-    header: &mut [u8],
-    kernel_len: usize,
-    setup_len: usize,
-    payload_offset: SetupVA,
-) {
-    fill_header_field(
-        header,
-        0x248, /* payload_offset */
-        &(usize::from(payload_offset) as u32).to_le_bytes(),
-    );
-
-    fill_header_field(
-        header,
-        0x24C, /* payload_length */
-        &(kernel_len as u32).to_le_bytes(),
-    );
-
-    fill_header_field(
-        header,
-        0x260, /* init_size */
-        &((setup_len + kernel_len) as u32).to_le_bytes(),
-    );
-}

ostd/libs/linux-bzimage/setup/.cargo/config.toml

@@ -1,3 +1,7 @@
+[env]
+# Provide a default value. Otherwise `Cargo check` won't work.
+PAYLOAD_FILE = "/PAYLOAD_FILE_is_not_defined"
+
 [target.x86_64-unknown-none]
 rustflags = [
     "-Ccode-model=kernel",

ostd/libs/linux-bzimage/setup/src/main.rs

@@ -22,22 +22,8 @@
 #![no_std]
 #![no_main]
 
-use linux_boot_params::BootParams;
-
 mod console;
 mod loader;
 
 // The entry points are defined in `x86/*/setup.S`.
 mod x86;
-
-fn get_payload(boot_params: &BootParams) -> &'static [u8] {
-    let hdr = &boot_params.hdr;
-    // The payload_offset field is not recorded in the relocation table, so we need to
-    // calculate the loaded offset manually.
-    let loaded_offset = x86::image_load_offset();
-    let payload_offset = (loaded_offset + hdr.payload_offset as isize) as usize;
-    let payload_length = hdr.payload_length as usize;
-    // SAFETY: the payload_offset and payload_length is valid if we assume that the
-    // boot_params struct is correct.
-    unsafe { core::slice::from_raw_parts_mut(payload_offset as *mut u8, payload_length) }
-}

ostd/libs/linux-bzimage/setup/src/x86/amd64_efi/efi.rs

@@ -67,8 +67,7 @@ fn efi_phase_boot(boot_params: &mut BootParams) -> ! {
     }
 
     // Load the kernel payload to memory.
-    let payload = crate::get_payload(boot_params);
-    let kernel = decode_payload(payload);
+    let kernel = decode_payload(crate::x86::payload());
 
     uefi::println!("[EFI stub] Loading payload.");
     crate::loader::load_elf(&kernel);

ostd/libs/linux-bzimage/setup/src/x86/header.S

@@ -4,10 +4,8 @@
 // See https://www.kernel.org/doc/html/v5.6/x86/boot.html for
 // more information on the Linux x86 Boot Protocol.
 
-// Some of the fields filled with a 0xab* values should be filled
-// by the torjan builder.
-// Asterinas will use only a few of these fields, and some of them
-// are filled by the loader and will be read by Asterinas.
+// The bootloader may fill some fields at runtime, which can
+// be read by the kernel (via `boot_params.hdr`).
 
 .section ".header", "a"
 
@@ -63,11 +61,11 @@ xloadflags:             .word 0
 cmdline_size:           .long 4096 - 1
 hardware_subarch:       .long 0
 hardware_subarch_data:  .quad 0
-payload_offset:         .long 0xabababab # at 0x248/4, to be filled by the builder
-payload_length:         .long 0xabababab # at 0x24c/4, to be filled by the builder
+payload_offset:         .long 0  # Not used.
+payload_length:         .long 0  # Not used.
 setup_data:             .quad 0
 pref_address:           .quad CODE32_START
-init_size:              .long 0xabababab # at 0x260/4, to be filled by the builder
+init_size:              .long __executable_size
 
 .if {CFG_TARGET_ARCH_X86_64}
 handover_offset:        .long (entry_efi_handover32 - entry_legacy32)

ostd/libs/linux-bzimage/setup/src/x86/legacy_i386/mod.rs

@@ -2,8 +2,6 @@
 
 use core::arch::{asm, global_asm};
 
-use linux_boot_params::BootParams;
-
 global_asm!(include_str!("setup.S"));
 
 use crate::console::{print_hex, print_str};
@@ -22,11 +20,7 @@ extern "cdecl" fn main_legacy32(boot_params_ptr: u32) -> ! {
         print_str("\n");
     }
 
-    // SAFETY: the boot_params_ptr is a valid pointer to be borrowed.
-    let boot_params = unsafe { &*(boot_params_ptr as *const BootParams) };
-    // SAFETY: the payload_offset and payload_length is valid.
-    let payload = crate::get_payload(boot_params);
-    crate::loader::load_elf(payload);
+    crate::loader::load_elf(crate::x86::payload());
 
     // SAFETY: the entrypoint and the ptr is valid.
     unsafe { call_aster_entrypoint(ASTER_ENTRY_POINT, boot_params_ptr.try_into().unwrap()) };

ostd/libs/linux-bzimage/setup/src/x86/linker.ld

@@ -38,11 +38,17 @@ SECTIONS
 
     // Text segment.
     . = SETUP32_LMA;
+    __executable_start = .;
     .setup                  : { KEEP(*(.setup)) } : text
     .text                   : { *(.text .text.*) } : text
 
     // Rodata segment.
     . = ALIGN(4096);
+    .payload                : {
+        PROVIDE(__payload_start = .);
+        KEEP(*(.payload))
+        PROVIDE(__payload_end = .);
+    } : rodata
     .rodata                 : { *(.rodata .rodata.*) } : rodata
     .rela                   : {
         PROVIDE(__rela_start = .);
@@ -59,6 +65,8 @@ SECTIONS
         *(.bss .bss.*) *(COMMON)
         PROVIDE(__bss_end = .);
     } : data
+    __executable_end = .;
+    __executable_size = __executable_end - __executable_start;
 
     . = ALIGN(4096);
     // Section names. ELF files must have them.

ostd/libs/linux-bzimage/setup/src/x86/mod.rs

@@ -32,3 +32,25 @@ pub fn image_load_offset() -> isize {
 
     (entry_legacy32 as usize as isize) - CODE32_START
 }
+
+global_asm!(
+    ".section \".payload\", \"a\"",
+    concat!(".incbin \"", env!("PAYLOAD_FILE"), "\""),
+);
+
+/// Returns an immutable slice containing the payload (i.e., the kernel).
+fn payload() -> &'static [u8] {
+    extern "C" {
+        fn __payload_start();
+        fn __payload_end();
+    }
+
+    // SAFETY: The memory region is part of the "rodata" segment, which is initialized, live for
+    // `'static`, and never mutated.
+    unsafe {
+        core::slice::from_raw_parts(
+            __payload_start as *const u8,
+            __payload_end as usize - __payload_start as usize,
+        )
+    }
+}