Re: [Question]or1k-elf/or1k-linux Windows/Cygwin toolchain availability?

[Stafford Horne <shorne@gmail.com>]

Hi Gary,

I see you sent 2 emails which are about the same.  I will reply only to this
one.

On Sat, Jul 12, 2025 at 03:11:43PM +0800, Gary Lau wrote:
> Hi openrisc folks,  
> 
> I’m exploring OpenRISC development and would like to build the linux kernel/busybox rootfs on Windows/Cygwin. 
> I wanted to check:  
> 1. Are prebuilt or1k-elf and or1k-linux toolchains available for Windows/Cygwin?  

There are none available at the moment.  We do have docker images however.  It
seems possible to run containers on windows.  But I haven't tried it.

 - Docker images: https://openrisc.io/tutorials/images.html
 - Containers on windows: https://ubuntu.com/tutorials/windows-ubuntu-hyperv-containers#1-overview

In terms of toolchains, you may only need an or1k-elf toolchain. The or1k-linux
toolchain is a special build with no libc library which is only good for
building the kernel, you can use or1k-elf to build the kernel too.

> 2. If not, is cross-compiling from Cygwin feasible, or is a native Linux host strongly recommended?  

I am sure it's possible, I have seen that ARM and Risc-V toolchains are
available on windows via cygwin.  They mention that to build the toolchain you
must ensure the filesystem is case-sensitive.  If you can get cygwin installed
with the GCC toolchain, you can then run our normal toolchain build script, the
one I use is this:

  - newlib.build: From https://github.com/stffrdhrn/or1k-utils/tree/master
  - example usage: From https://github.com/stffrdhrn/or1k-toolchain-build/blob/master/or1k-toolchain-build/build-gcc.sh

      # Setup overrides for newlib.config
      export NOTIFY=n
      export BUILDDIR=$PWD
      export GCC_SRC=$(archive_src gcc ${GCC_VERSION})
      export BINUTILS_SRC=$(archive_src binutils ${BINUTILS_VERSION})
      export GDB_SRC=$(archive_src gdb ${GDB_VERSION})
      export NEWLIB_SRC=$(archive_src newlib ${NEWLIB_VERSION})
      export INSTALLDIR=$PREFIX
      export CROSS=${target}
      ../or1k-utils/toolchains/newlib.build

> I checked the OpenRISC docs and toolchain repos but couldn’t find Windows-specific  
> guidance. Any pointers would be helpful!  

You can mainly look for risc-v and arm guidance and then translate it to
OpenRISC.  If you get anything working please let me know, we can try to add it
as a tutorial to our main documentation.

-Stafford