calee0219 / osc2021

Homework submission for student

My OSC 2021

Author

學號	GitHub 帳號	姓名	Email
0856004	calee0219	李家安	[e-mail], [e-mail] [e-mail]

How to build

Install toolchain

On Fedora

sudo dnf install -y clang                       # Using clang as compiler
sudo dnf install -y lld                         # Using llvm lld as linker
sudo dnf install -y llvm                        # Using llvm-objcopy as obj file translator
sudo dnf install -y qemu                        # Using qemu as emulator
sudo dnf install -y make                        # Using make as make tools

Build project

# All in one
make all    # or make
# Seperated
make obj    # Generate all obj file (.S to .o)
make elf    # Generate ELF file (link obj)
make img    # copy elf to image file, same as make all
# For optional build
ENV=debug make
LANG=rust make # not implement yet

How to run

Run in qemu and show console

qemu-system-aarch64 -M raspi3 -kernel ./kernel8.img -display none -serial null -serial stdio
# -M/-machine: Supported machine, here using Raspberry Pi 3B
# -display: display backend type, none, gtk, ...

Debug on qemu

• Using debug mode when build: ENV=debug make
• Run qemu-system-aarch64 -M raspi3 -kernel ./kernel8.img -display none -serial null -serial stdio -s -S
• Run gdb -x gdbcmd.gdb

How to burn it into pi3

Burn into micro SD card

dd if=nctuos.img of=/dev/sdc bs=512 # if for input, of for output, bs for block size
cp kernel8.img ${your SD card mount folder} # replace kernel8.elf with your image

UART ping

UART	RPi
GND	GND / ping 6
RXD	UARTD_TXD / ping 8 / GPIO 14
TXD	UARTD_RXD / ping 10 / GPIO 15

Host tty attach

dmesg | grep -i tty                # Using dmesg command to check tty
sudo screen /dev/ttyUSB0 115200    # Attach tty using root permission, or screen may terminate

Architecture

boot.S for sp set, bss clear, then jump to kernel (write by C)

Directory structure

• Folder architecture

  /osc2021

├── bootloader [4/2622] │   ├── include
│   │   ├── mmio.h
│   │   ├── shell.h
│   │   └── util.h
│   ├── linker.lds │   ├── linker_qemu.lds │   ├── Makefile │   └── src │   ├── bootloader.c │   ├── boot.S │   ├── mmio.c │   ├── shell.c │   └── util.c ├── LICENSE ├── Makefile ├── Makefile.env ├── Makefile.inc ├── os │   ├── boot │   │   └── boot.S │   ├── kernel │   │   ├── include │   │   │   ├── cpio.h │   │   │   ├── mmio.h │   │   │   ├── shell.h │   │   │   └── util.h │   │   ├── Makefile │   │   └── src │   │   ├── cpio.c │   │   ├── kernel.c │   │   ├── mmio.c │   │   ├── shell.c │   │   └── util.c │   ├── linker.lds │   ├── linker_qemu.lds │   └── Makefile ├── README.md ├── REFERENCE.md ├── setup │   ├── bootcode.bin │   ├── config.txt │   ├── fixup.dat │   ├── initramfs.cpio │   ├── kernel8.img │   └── start.elf └── tools ├── boot_uart.py └── gdbcmd.gdb

- File usage
- boot: Files for boot up, runs before kernel
- c-impl: The kernel source code that implement in C language
  - include: .h header file
  - lib: .c source file, also place object file here after compile
  - kernel.c: main process after OS boot up
- rust-impl: The kernel source code that implement in rust language
- *.gdb: gdb helper file
- linker.lds: linker script
- Makefile: makefile for os
- README.md: documentation
- REFERENCE.md: reference link when doing the labs