Overview
Emulate an ARM processor on Intel using CentOS 7 and Qemu.
Prerequisite Packages
Qemu
# dnf install qemu-kvmCross-compilation
# dnf install bc bison flex gcc git glibc-2.28-101.el8.i686 libstdc++-devel.i686 make openssl-devel ncurses ncurses-devel zlib.i686Acquire Resources
Create a working directory in your unprivileged user home directory and clone the raspbian kernel source:
$ mkdir -p ~/git/raspberrypi
$ cd ~/git/raspberrypi
$ git clone --depth=1 https://github.com/raspberrypi/linuxAlso get the Raspbian toolchain:
$ git clone https://github.com/raspberrypi/toolsDownload a current version of Raspbian from downloads.raspberrypi.org and unpack. This example uses Raspbian Lite 2020-02-14:
$ wget http://downloads.raspberrypi.org/raspbian_lite/images/raspbian_lite-2020-02-14/2020-02-13-raspbian-buster-lite.zip
$ unzip 2020-02-13-raspbian-buster-lite.zipInspect the Raspbian Image
$ fdisk -l 2020-02-13-raspbian-buster-lite.imgThe output will show two partitions. When we emulate, this img file will be handed off as hda, so these two partitions will be seen by the emulator as sda1 and sda2.
Configure and Cross-Compile Kernel
Executing $ file ${HOME}/git/raspbian/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/arm-linux-gnueabihf-gcc reveals that the Linaro ARM cross-compiler in the Raspbian toolchain is dynamically linked; necessitating the i686 glibc, libstdc++, and zlib packages installed (above).
The kernel will be configured to support a minimal number of features, architectures, and filesystems:
$ cd linux
$ export KERNEL="kernel7"
$ export ARCH="arm"
$ export CROSS_COMPILE="${HOME}/git/raspbian/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/arm-linux-gnueabihf-"
$ make bcm2709_defconfig
$ make menuconfig
$ make all
$ cd ..ARM/Raspberry Pi Emulation
$ export QEMU_AUDIO_DRV=none
$ qemu-system-arm \
-kernel linux/vmlinux \
-cpu arm1176 \
-m 256M \
-machine versatilepb \
-no-reboot \
-serial stdio \
-append "root=/dev/sda2 panic=1 rootfstype=ext4 rw init=/bin/bash" \
-drive file=2020-02-13-raspbian-buster-lite.img,format=raw,index=0,media=diskCommand breakdown (please see man qemu-system-arm for further detail):
| Parameter | Description |
|---|---|
| export QEMU_AUDIO_DRV=none | Disable audio |
| qemu-system-arm | QEMU binary that emulates ARM processors |
| -kernel linux/vmlinux | Path to the kernel (built above) |
| -cpu arm1176 | Specific ARM processor to emulate |
| -m 256M | Memory in MB |
| -machine versatilepb | Machine type to emulate. Additional types can be enumerated with qemu-system-arm -machine help |
| -no-reboot | |
| -serial stdio | Directs serial output to stdio (linux only) |
| -append “root=/dev/sda2 panic=1 rootfstype=ext4 rw init=/bin/bash” | Options to pass to the kernel to describe filesystem details and initial processes |
| -drive file=2020-02-13-raspbian-buster-lite.img,format=raw,index=0,media=disk | Disk image containing the filesystem(s) |
Relevant Links
- Compile Linux Kernel 3.2 for ARM and Emulate with Qemu
- Full Raspberry Pi (Raspbian) Emulation with Qemu
- Kernel Building
- How can I mount a Raspberry Pi Linux distro image?
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