Alpine Kernel

A minimal x86 kernel

Install

1. Install cross compiler:brew install x86_64-elf-gcc objconv
2. Clone GRUB: git clone git://git.savannah.gnu.org/grub.git
3. Run GRUB's autogen: cd grub && ./autogen.sh
4. Configure GRUB build: ../grub/configure --disable-werror TARGET_CC=x86_64-elf-gcc TARGET_OBJCOPY=x86_64-elf-objcopy TARGET_STRIP=x86_64-elf-strip TARGET_NM=x86_64-elf-nm TARGET_RANLIB=x86_64-elf-ranlib --target=x86_64-elf
5. Build and install GRUB: make && make install

Live USB

1. Prerequisites: brew install balena-cli
2. Insert the usb device
3. Run ./flashusb.sh
4. Select the usb device to flash and hit Enter
5. Enter 'y' when prompted (pass -y to ./flashusb.sh to skip this step)

Debug

• Get a disassembly of the kernel
  • x86_64-elf-objdump -D build/alpine.kernel > kernel.dump
• Get debug logs and cpu traces from Qemu
  • Enable logging: ./qemu.sh -D qemu.log
  • Log interrupts/exceptions: add -d int
  • Log cpu state before reset: add -d cpu_reset
  • Get list of supported logs: qemu-system-x86_64 -d --help