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THIS REPOSITORY IS NOW OBSOLETE!
We are now using an autobuilder to build all packages for
Fedora/RISC-V. For information, read:
https://fedoraproject.org/wiki/Architectures/RISC-V/Building
The old README is preserved below so you can read how we bootstrapped
Fedora/RISC-V.
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A plan for Fedora/RISC-V
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by Richard W.M. Jones (rjones@redhat.com)
Project home page: https://fedoraproject.org/wiki/Architectures/RISC-V
The aim of the project
----------------------
Get Fedora running on the RISC-V architecture! This will just be an
initial pass, which we're calling an "experimental architecture". It
won't even be a secondary architecture for perhaps 1 to 3 years.
About Fedora: https://getfedora.org/
About RISC-V: https://riscv.org/
https://en.wikipedia.org/wiki/RISC-V
lowRISC: http://www.lowrisc.org/
SiFive: https://www.sifive.com/
How do we expect people to consume Fedora/RISC-V?
-------------------------------------------------
Most users will download binaries. Of course source will be available
for everything, buildable from source RPMS.
Currently no hardware is available, so you either have to run RISC-V
on an FPGA, or use emulation, either QEMU or Spike.
For the FPGA option, you will need a Nexys 4 DDR development kit
costing around US$341, plus an ordinary micro SD card (8+ GB), plus a
host Fedora/x86-64 computer.
- Maximum system RAM is 128 MB (1 GB is available if you use the
other far more expensive FPGA development kit)
- There is a 115200 bps 8n1 serial port.
- There is no ethernet and no display.
- Note that some parts of the FPGA toolchain are closed source.
For the QEMU emulation option, you will need Fedora 24 (x86_64).
- QEMU has unlimited system RAM.
- Single virtual CPU.
- We hope to get virtio-net and maybe virtio-scsi working.
For the Spike emulation option, you will need Fedora 24 (x86_64).
- Spike has unlimited system RAM.
- Spike can emulate multiple virtual CPUs.
- Spike's single thread performance is a bit slower than QEMU.
- No network.
What parts of Fedora are we aiming to build?
--------------------------------------------
The @Core packages (as RPMs), rpmbuild, gcc, and a bootable binary
disk image.
For the list of packages in @Core, see:
https://github.com/rwmjones/fedora-riscv/blob/master/packages-in-core
Only 64 bit RISC-V ("riscv64") will be targeted.
Once those are done, we can declare victory.
What parts of Fedora are we *not* aiming to build?
--------------------------------------------------
Nothing outside @Core except for specific compilers and build tools.
Not Anaconda.
Not Koji (at least, not at first).
Not Grub nor EDK2. We will initially use the Berkeley bootloader
(bbl), but aim for a standard bootloader later.
Where will we build it?
-----------------------
The packages which are run on the host (x86-64) computer are built in
COPR (http://copr-fe.cloud.fedoraproject.org/coprs/rjones/riscv/).
However the majority of packages will be built on RISC-V itself.
Since there are no RISC-V builders, and we cannot provide any,
initially developers will be building them on their own FPGAs /
emulators and uploading them to somewhere central.
Getting build infrastructure would be a more long-term aim.
Bootstrapping stages
--------------------
[This plan was loosely based on:
https://fedoraproject.org/wiki/Architectures/AArch64/Bootstrap]
Bootstrapping, Stage 1
----------------------
(1a) riscv-qemu.x86_64: QEMU + RISC-V system emulation
Not upstream, fork of qemu 2.5.0.
https://github.com/riscv/riscv-qemu
Status: done http://copr-fe.cloud.fedoraproject.org/coprs/rjones/riscv
Note this package runs on x86-64 hosts, and is intended for people who
want to run Fedora/RISC-V but who do not have FPGA/hardware.
(1b) riscv-isa-sim.x86_64: Spike system emulator
https://github.com/riscv/riscv-isa-sim
Status: done http://copr-fe.cloud.fedoraproject.org/coprs/rjones/riscv
(1c) Nexys4 DDR FPGA
Various sources, see:
http://www.lowrisc.org/docs/untether-v0.2/fpga-demo/
Bootstrapping, Stage 2
----------------------
(2a) GNU cross-compiler toolchain.
https://github.com/lowRISC/riscv-gnu-toolchain
Status: done http://copr-fe.cloud.fedoraproject.org/coprs/rjones/riscv
(2b) Berkley Bootloader (bbl)
https://github.com/lowrisc/riscv-pk.git
Status: done http://copr-fe.cloud.fedoraproject.org/coprs/rjones/riscv
Used to boot the kernel and mount the root filesystem on FPGAs and
QEMU.
Bootstrapping, Stage 3
----------------------
(3a) kernel.riscv64: The Linux kernel, cross-compiled.
https://github.com/lowrisc/riscv-linux
Not upstream fork of Linux 4.1.
Status: done, see Makefile rule stage3-kernel/linux-*/vmlinux
(3b) "Just enough userspace"
We cross-compile packages from x86-64 host to riscv64 target
filesystem. The aim is to have a filesystem (not RPMs) that can be
booted on RISC-V hardware or under emulation, which will be sufficient
to use to compile RPMs.
Status: done, see Makefile rules stage3-chroot/* and
http://oirase.annexia.org/riscv/
Bootstrapping, Stage 4
----------------------
(4a) Userspace RPMs
We will build RPMs using "rpmbuild" on RISC-V itself (under emulation).
Full details of this step are on the wiki:
https://fedoraproject.org/wiki/Architectures/RISC-V/Bootstrapping
Status: ongoing, see stage3-built-rpms/*
(4b) Recreate the filesystem from RPMs.
Distribute an initial bootable binary disk image which is completely
built from RPMs (but note: not created by Anaconda, we'll use
"rpm --root").
(4c) kernel.riscv64: The Linux kernel, compiled as an RPM on RISC-V.
(4d) Continue compiling all other RPMs from @Core.
For the list of packages in @Core, see:
https://github.com/rwmjones/fedora-riscv/blob/master/packages-in-core
As more packages are compiled, distribute them as RPMs and distribute
updated bootable binary disk image.
(4e) Declare victory and celebrate!
Open issues
-----------
(none at present)