Buildroot

For Xuantie CPU Series Kernel build

Introduction

Buildroot is a tool that simplifies and automates the process of building a complete Linux system for an embedded system, using cross-compilation. In order to achieve this, Buildroot is able to generate a cross-compilation toolchain, a root filesystem, a Linux kernel image and a bootloader for your target. Buildroot can be used for any combination of these options, independently (you can for example use an existing cross-compilation toolchain, and build only your root filesystem with Buildroot).

This repositery is based on buildroot official repo and project-specific customization is made for Xuantie CPU Series' opensource ecosystem.

Quick Start

clone repository

git clone https://github.com/c-sky/buildroot.git
cd buildroot

choose a suitable config file

Multiple customized config files are provided in folder configs_enhanced

CPU	suitable config file
C910v2	thead_910v2_enhanced_5.10_glibc_br_defconfig
C920v2	thead_920v2_enhanced_5.10_glibc_br_defconfig
C906, C908, C910v1	thead_9xxf_enhanced_5.10_glibc_br_defconfig
C920v1	thead_9xxv0p7_enhanced_5.10_glibc_br_defconfig
C908v	thead_9xxv_enhanced_5.10_glibc_br_defconfig

Build kernel opensbi & rootfs

make CONF=thead_9xxf_enhanced_5.10_glibc_br_defconfig

Then inside image folder thead_9xxf_enhanced_5.10_glibc_br_defconfig/images/ you will get:

fw_jump.bin # OpenSPI with jump address mode
fw_dynamic.bin # OpenSPI with dynamic info mode
Image # Linux Kernel image 
rootfs.ext2 # Root filesystem 

Use Qemu boot Linux

./host/csky-qemu/bin/qemu-system-riscv64 -M virt -cpu c910 \
-kernel ./images/fw_jump.bin \
-device loader,file=./images/Image,addr=0x80200000 \
-append "rootwait root=/dev/vda ro" \
-drive file=./images/rootfs.ext2,format=raw,id=hd0 \
-device virtio-blk-device,drive=hd0 \
-nographic -smp 2

Using FPGA boot Linux

For booting linux with FPGA, dts, gdbinit scripts also will be needed, apart from kernel and rootfs. thoes scripts can be found inside folder thead_9xxf_enhanced_5.10_glibc_br_defconfig/images/hw. please referring documents for more details

See Linux Booting

[ 1.635084] VFS: Mounted root (ext4 filesystem) readonly on device 254:0.
[ 1.638991] devtmpfs: mounted
[ 1.671150] Freeing unused kernel memory: 252K
[ 1.729521] Run /sbin/init as init process
[ 1.861620] EXT4-fs (vda): warning: mounting unchecked fs, running e2fsck is recommended
[ 1.866438] EXT4-fs (vda): re-mounted. Opts: (null)
Starting syslogd: OK
Starting klogd: OK
Running sysctl: OK
Starting mdev... OK
Initializing random number generator: OK
Saving random seed: [ 5.720512] random: dd: uninitialized urandom read (512 bytes read)
OK
Starting network: OK
Starting telnetd: OK
processor : 0
hart : 0
isa : rv64imafdcsu
mmu : sv39
model name : T-HEAD C910
freq : 1.2GHz
icache : 64kB
dcache : 64kB
l2cache : 2MB
tlb : 1024 4-ways
cache line : 64Bytes
address sizes : 40 bits physical, 39 bits virtual
vector version : 0.7.1
processor : 1
hart : 1
isa : rv64imafdcsu
mmu : sv39
model name : T-HEAD C910
freq : 1.2GHz
icache : 64kB
dcache : 64kB
l2cache : 2MB
tlb : 1024 4-ways
cache line : 64Bytes
address sizes : 40 bits physical, 39 bits virtual
vector version : 0.7.1
Skip the ci test
Welcome to Buildroot
buildroot login:

Resources

• https://www.xrvm.cn/vendor/cpu/cpuList
• https://www.xrvm.cn/product/list/xuantie
• https://www.xrvm.cn/document?slug=linux-user-manual
• https://github.com/T-head-Semi/opensbi
• https://github.com/T-head-Semi/linux