XiuTsong / uefi-project

uefi-project

Prerequesites

​ (If you have done labs in class before, this section can be skipped.)

1. Update the package managers database.

sudo apt-get update

2. Install the following packages.

sudo apt-get install  \
        flex bison build-essential make libncurses5-dev openssl libssl-dev \
        uuid-dev g++sl nasm iasl \
    	qemu

Besides, qemu-system-x86 is also required. We recommend using version 8.0.4.

$ qemu-system-x86_64 -version
QEMU emulator version 8.0.4
Copyright (c) 2003-2022 Fabrice Bellard and the QEMU Project developers

Setup

Clone this repository.

git clone https://github.com/XiuTsong/uefi-project.git

Update edk2 submodule.

git submodule update --recursive --init

Configure edk2(You can refer to the previous slides given by TA).

cd edk2
make -C BaseTools
source edksetup.sh BaseTools
cd ..

# you will find there are file edk2/Conf/target.txt
# edit this file, set the following setting.
#
# ACTIVE_PLATFORM  = OvmfPkg/OvmfPkgX64.dsc
# TARGET_ARCH      = X64
# TOOL_CHAIN_TAG   = GCC5

Configure linux

cd linux
cp myconfig .config

Configure busybos

cd busybox/_install
sudo mkdir dev 
sudo mknod dev/console c 5 1
sudo mknod dev/ram b 1 0
# You could also add your .bin file to _install

Enter the directory run-ovmf, use the following command to compile edk2 and linux kernel.

make all

Besides, you can compile edk2, linux and initramfss separately.

# Compile edk2
make edk2
# Compile linux
make linux
# Compile busybox
make initramfs

If you have problem compiling edk2, it is likely that edk2 is not fully cloned. You can first delete the edk2 folder with rm - rf, and then clone it with the following command:

git clone --recursive [e-mail]:XiuTsong/uefi-edk2.git edk2
cd edk2
git pull

Run

Also in directory run-ovmf, use the following command to run qemu.

make run-only

If you want to quit qemu, you can simply type ctrl+a x in your terminal.

If you want to debug linux kernel, you can open one terminal and type the following command.

make run

And then you should touch a .gdbinit file in run-ovmf, just like the follows:

# .gdbinit
target remote localhost:1234
add-symbol-file ../linux/vmlinux

Open another terminal and type:

gdb -n -x .gdbinit

Now you can create some breakpoint in linux kernel and type c to continue.

modify the syscall

usr mode (test/syscall.c)

可执行文件位于busybox/_install/syscall，即进入kernel后根目录的 syscall文件，用法为./syscall $service_name $paras(任意数量)。

该文件由test/syscall.c静态编译而来，一般无需修改。

若确需修改，请参照一下命令使其应用于kernel中。

cd test
gcc -static -o syscall syscall.c
rm ../busybox/_install/syscall
cp syscall ../busybox/_install
cd ../run-ovmf
make initramfs

kernel

在kernel内核中，如需添加对新服务的调用或修改对老服务的调用方式，泽只需要对该文件(linux/kernel/sys.c)下图部分进行修改。

//comm为传递进来的service_name,枚举比较其名称（time_key）
  // add service here
  if (!strncmp(comm, "time_key", 10)) {
    efi_status_t status;
    pr_info("test_efi begin.\n");
    ...
  }

对所传递参数的取用例子

//kargs[i]为第i个参数
pr_info("test_efi para %d: %s.\n", i, kargs[i]);