Utilize libflate crate to compress and decompress payload

ostd/libs/linux-bzimage/setup/Cargo.toml

@@ -14,6 +14,8 @@ path = "src/main.rs"
 
 [dependencies]
 cfg-if = "1.0.0"
+core2 = { version = "0.4.0", default-features = false, features = ["nightly"] }
+libflate = { version = "2.1.0", default-features = false }
 linux-boot-params = { path = "../boot-params", version = "0.1.0" }
 uart_16550 = "0.3.0"
 xmas-elf = "0.8.0"

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

@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: MPL-2.0
+
+//! This module is used to decompress payload.
+
+extern crate alloc;
+
+pub use alloc::vec::Vec;
+use core::convert::TryFrom;
+
+use core2::io::Read;
+use libflate::{gzip, zlib};
+
+enum MagicNumber {
+    Elf,
+    Gzip,
+    Zlib,
+}
+
+impl TryFrom<&[u8]> for MagicNumber {
+    type Error = &'static str;
+
+    fn try_from(slice: &[u8]) -> Result<Self, Self::Error> {
+        match *slice {
+            [0x7F, 0x45, 0x4C, 0x46, ..] => Ok(Self::Elf),
+            [0x1F, 0x8B, ..] => Ok(Self::Gzip),
+            [0x78, 0x9C, ..] => Ok(Self::Zlib),
+            _ => Err("Unsupported payload type"),
+        }
+    }
+}
+
+/// Checking the encoding format and matching decoding methods to decode payload.
+pub fn decode_payload(payload: &[u8]) -> Vec<u8> {
+    let mut kernel = Vec::new();
+    let magic = MagicNumber::try_from(payload).unwrap();
+    match magic {
+        MagicNumber::Elf => {
+            kernel = payload.to_vec();
+        }
+        MagicNumber::Gzip => {
+            let mut decoder = gzip::Decoder::new(payload).unwrap();
+            decoder.read_to_end(&mut kernel).unwrap();
+        }
+        MagicNumber::Zlib => {
+            let mut decoder = zlib::Decoder::new(payload).unwrap();
+            decoder.read_to_end(&mut kernel).unwrap();
+        }
+    }
+    kernel
+}

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

@@ -8,6 +8,7 @@ use uefi::{
 };
 
 use super::{
+    decoder::decode_payload,
     paging::{Ia32eFlags, PageNumber, PageTableCreator},
     relocation::apply_rela_dyn_relocations,
 };
@@ -55,9 +56,11 @@ fn efi_phase_boot(
 
     uefi_services::println!("[EFI stub] Relocations applied.");
 
-    uefi_services::println!("[EFI stub] Loading payload.");
     let payload = unsafe { crate::get_payload(&*boot_params_ptr) };
-    crate::loader::load_elf(payload);
+    let kernel = decode_payload(payload);
+
+    uefi_services::println!("[EFI stub] Loading payload.");
+    crate::loader::load_elf(&kernel);
 
     uefi_services::println!("[EFI stub] Exiting EFI boot services.");
     let memory_type = {

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

@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: MPL-2.0
 
+mod decoder;
 mod efi;
 mod paging;
 mod relocation;