Clone and build and install the RISC-V GNU tool chain.
How to build the riscv-gnu-toolchain project
./configure --prefix=/opt/riscv
make
or
make linux
Add /opt/riscv to the PATH.
You can alter the configuration according to the requirements.
./configure --prefix=/opt/riscv-zifencei --host=riscv64-unknown-elf --with-arch=rv64imafdczifencei
make