1.第一步 clone 需要的源文件（sudo apt install git 如果你没有git） 以下都是给予ubuntu18.04
$ git clone --recursive https://github.com/riscv/riscv-gnu-toolchain 或者 $ git clone https://github.com/riscv/riscv-gnu-toolchain $ cd riscv-gnu-toolchain $ git submodule update --init --recursive
2.依赖项
$ sudo yum install autoconf automake libmpc-devel mpfr-devel gmp-devel gawk bison flex texinfo patchutils gcc gcc-c++ zlib-devel expat-devel
3.installation(newlib) 构建newlib交叉编译器 我的内核使用32位所以下面介绍32位
cd riscv-gnu-toolchain ./configure --prefix=/opt/riscv --with-arch=rv32emc --with-abi=ilp32e sudo make # sudo needed if installing under default /opt/riscv location
4.构建linux交叉编译器32位
./configure --prefix=/opt/riscv --with-arch=rv32gc --with-abi=ilp32d make linux
可能出现的问题 centos和rhel编译器过久可能会失败
Troubleshooting Build Problems Builds work best if installing into an empty directory. If you build a hard-float toolchain and then try to build a soft-float toolchain with the same --prefix directory, then the build scripts may get confused and exit with a linker error complaining that hard float code can't be linked with soft float code. Removing the existing toolchain first, or using a different prefix for the second build, avoids the problem. It is OK to build one newlib and one linux toolchain with the same prefix. But you should avoid building two newlib or two linux toolchains with the same prefix. If building a linux toolchain on a MacOS system, or on a Windows system using the Linux subsystem or cygwin, you must ensure that the filesystem is case-sensitive. A build on a case-insensitive filesystem will fail when building glibc because *.os and *.oS files will clobber each other during the build eventually resulting in confusing link errors. Centos (and RHEL) provide old GNU tools versions that may be too old to build a RISC-V toolchain. There is an alternate toolset provided that includes current versions of the GNU tools. This is the devtoolset provided as part of the Software Collection service. For more info, see the devtoolset-7 URL. There are various versions of the devtoolset that are available, so you can also try other versions of it, but we have at least one report that devtoolset-7 works.
参考网址
https://github.com/riscv/riscv-gnu-toolchain#installation-newlib