经常重装系统，所以记录一下。
- 换源
sudo gedit /etc/apt/sources.list
删除sources.list所有内容，添加
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-security main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-security main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse
再输入
sudo apt-get update
sudo apt-get upgrade
- 下载解压riscv-tools
git下载过程可能比较缓慢，这里提供其他下载链接: 百度云.提取码 0t12
下载完zip压缩包后，找到合适的位置解压
unzip risc-tools.zip
- 编译riscv-tools
编译前先安装依赖
sudo apt-get install autoconf automake autotools-dev curl libmpc-dev libmpfr-dev libgmp-dev libusb-1.0-0-dev gawk build-essential bison flex texinfo gperf libtool patchutils bc zlib1g-dev device-tree-compiler pkg-config libexpat-dev
sudo apt install openjdk-8-jdk-headless
sudo apt install git
sudo apt install python
设置环境变量，RISCV路径是工具链存放的位置自己选择，MAKEFLAGS中的-j6代表用6核来跑，这个根据自己CPU的情况，一般越多越快。
export RISCV=/home/k/riscv-toolchain
export MAKEFLAGS="$MAKEFLAGS -j6"
编译
cd riscv-tools
./build.sh
- 获取rocket repo 这里最好搭梯子，国内的速度慢
git clone https://github.com/ucb-bar/rocket-chip.git
cd rocket-chip
git submodule update --init
- 生成C++ emulator测试
cd rocket-chip/emulator
make -j6 run
没有报错则riscv-tools和rocket安装编译成功，接下来可以做想做的实验了