1 A plan for Fedora/RISC-V
2 ----------------------------------------------------------------------
3 by Richard W.M. Jones (rjones@redhat.com)
5 Project home page: https://fedoraproject.org/wiki/Architectures/RISC-V
11 Get Fedora running on the RISC-V architecture! This will just be an
12 initial pass, which we're calling an "experimental architecture". It
13 won't even be a secondary architecture for perhaps 1 to 3 years.
15 About Fedora: https://getfedora.org/
16 About RISC-V: https://riscv.org/
17 https://en.wikipedia.org/wiki/RISC-V
18 lowRISC: http://www.lowrisc.org/
21 How do we expect people to consume Fedora/RISC-V?
22 -------------------------------------------------
24 Most users will download binaries. Of course source will be available
25 for [almost*] everything, buildable from source RPMS.
27 Currently no hardware is available, so you either have to run RISC-V
28 on an FPGA, or use QEMU/Spike emulation.
30 For the FPGA option, you will need a Nexys 4 DDR development kit
31 costing around US$341, plus an ordinary micro SD card (8+ GB), plus a
32 host Fedora/x86-64 computer.
34 - Maximum system RAM is 128 MB (1 GB is available if you use the
35 other far more expensive FPGA development kit)
37 - There is a 115200 bps 8n1 serial port.
39 - There is no ethernet and no display.
41 For the QEMU emulation option, see below.
43 - QEMU has unlimited system RAM.
45 - Network access is available.
47 For the Spike emulation option, see below.
49 - Spike has unlimited system RAM.
54 [*] Some CPU peripherals use proprietary IP. The aim is to replace
55 these with open equivalents eventually. Building the FPGA bitstream
56 will require proprietary tools, although the source itself is free
60 What parts of Fedora are we aiming to build?
61 --------------------------------------------
63 The @Core packages (as RPMs), rpmbuild, gcc, and a bootable binary
66 Only 64 bit RISC-V will be targeted.
68 Once those are done, we can declare victory.
71 What parts of Fedora are we *not* aiming to build?
72 --------------------------------------------------
74 Nothing outside @Core except for specific compilers and build tools.
78 Not Koji (at least, not at first).
80 Not Grub nor EDK2. We will initially use the Berkeley bootloader
81 (bbl), but aim for a standard bootloader later.
84 Where will we build it?
85 -----------------------
87 The packages which are run on the host (x86-64) computer will be built
88 in COPR (https://copr.fedorainfracloud.org/).
90 However the majority of packages will be built on RISC-V itself.
91 Since there are no RISC-V builders, and we cannot really provide them,
92 initially developers will be building them on their own FPGAs /
93 emulators and uploading them.
95 Getting build infrastructure would be a more long-term aim.
100 [See also: https://fedoraproject.org/wiki/Architectures/AArch64/Bootstrap]
104 (1a) riscv-qemu.x86_64: QEMU + RISC-V system emulation
106 Not upstream, fork of qemu 2.5.0.
107 https://github.com/riscv/riscv-qemu
108 Status: done http://copr-fe.cloud.fedoraproject.org/coprs/rjones/riscv
110 Note this package runs on x86-64 hosts, and is intended for people who
111 want to run Fedora/RISC-V but who do not have FPGA/hardware.
113 (1b) riscv-isa-sim.x86_64: Spike system emulator
115 Since QEMU is broken at the moment, we must use the slower Spike
120 Various sources, see:
121 http://www.lowrisc.org/docs/untether-v0.2/fpga-demo/
125 (2a) GNU cross-compiler toolchain.
127 https://github.com/lowRISC/riscv-gnu-toolchain
128 Status: done http://copr-fe.cloud.fedoraproject.org/coprs/rjones/riscv
130 (2b) Berkley Bootloader (bbl)
132 https://github.com/lowrisc/riscv-pk.git
133 Status: done http://copr-fe.cloud.fedoraproject.org/coprs/rjones/riscv
135 Used to boot the kernel and mount the root filesystem on FPGAs and
140 (3a) kernel.riscv64: The Linux kernel, cross-compiled.
142 Current status: Not upstream, fork of Linux 4.6.
143 https://github.com/lowrisc/riscv-linux
145 (3b) "Just enough userspace"
147 The following packages, cross-compiled from x86-64 host to riscv64
148 target filesystem. The aim is to have a filesystem (not RPMs) that
149 can be booted on RISC-V hardware or under QEMU, which will be
150 sufficient to use to compile RPMs.
159 filesystem.riscv64 (?)
167 We will also need to add the following noarch packages (these do not
168 need to be compiled, they can just be copied from another Fedora
172 ca-certificates.noarch
173 crypto-policies.noarch
174 emacs-filesystem.noarch
175 fedora-release.noarch
180 ==== At this point, Fedora on RISC-V will be self-hosting ====
184 (4a) kernel.riscv64: The Linux kernel, compiled as an RPM on RISC-V.
188 (See the above list of packages, but built from SRPMs)
190 (4c) Recreate the filesystem from RPMs.
192 Distribute an initial bootable binary disk image which is completely
193 built from RPMs (but note, not created by Anaconda).
195 (4d) Continue compiling all other RPMs from @Core.
197 As more packages are compiled, distribute them as RPMs and distribute
198 updated bootable binary disk image.
200 (4e) Declare victory and celebrate!
206 What architecture string to use (eg. in RPM package names)? There are
207 32, 64 and (in theory) 128 bit variants of RISC-V. GNU uses "riscv64".