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 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.
48 [*] Some CPU peripherals use proprietary IP. The aim is to replace
49 these with open equivalents eventually. Building the FPGA bitstream
50 will require proprietary tools, although the source itself is free
54 What parts of Fedora are we aiming to build?
55 --------------------------------------------
57 The @Core packages (as RPMs), rpmbuild, gcc, and a bootable binary
60 Only 64 bit RISC-V will be targeted.
62 Once those are done, we can declare victory.
65 What parts of Fedora are we *not* aiming to build?
66 --------------------------------------------------
68 Nothing outside @Core except for specific compilers and build tools.
72 Not Koji (at least, not at first).
74 Not Grub nor EDK2. We will initially use the Berkeley bootloader
75 (bbl), but aim for a standard bootloader later.
78 Where will we build it?
79 -----------------------
81 The packages which are run on the host (x86-64) computer will be built
82 in COPR (https://copr.fedorainfracloud.org/).
84 However the majority of packages will be built on RISC-V itself.
85 Since there are no RISC-V builders, and we cannot really provide them,
86 initially developers will be building them on their own FPGAs / QEMUs
89 Getting build infrastructure would be a more long-term aim.
94 [See also: https://fedoraproject.org/wiki/Architectures/AArch64/Bootstrap]
98 (1a) riscv-qemu.x86_64: QEMU + RISC-V system emulation
100 Current status: Not upstream, fork of qemu 2.5.0.
101 https://github.com/riscv/riscv-qemu
103 Note this package runs on x86-64 hosts, and is intended for people who
104 want to run Fedora/RISC-V but who do not have FPGA/hardware.
108 Various sources, see:
109 http://www.lowrisc.org/docs/untether-v0.2/fpga-demo/
111 (1c) Berkley Bootloader (bbl)
113 Used to boot the kernel and mount the root filesystem on FPGAs and
114 QEMU. See link above.
118 (2a) GNU cross-compiler toolchain.
120 https://github.com/lowRISC/riscv-gnu-toolchain
124 (3a) kernel.riscv64: The Linux kernel, cross-compiled.
126 Current status: Not upstream, fork of Linux 4.6.
127 https://github.com/lowrisc/riscv-linux
129 (3b) "Just enough userspace"
131 The following packages, cross-compiled from x86-64 host to riscv64
132 target filesystem. The aim is to have a filesystem (not RPMs) that
133 can be booted on RISC-V hardware or under QEMU, which will be
134 sufficient to use to compile RPMs.
143 filesystem.riscv64 (?)
151 We will also need to add the following noarch packages (these do not
152 need to be compiled, they can just be copied from another Fedora
156 ca-certificates.noarch
157 crypto-policies.noarch
158 emacs-filesystem.noarch
159 fedora-release.noarch
164 ==== At this point, Fedora on RISC-V will be self-hosting ====
168 (4a) kernel.riscv64: The Linux kernel, compiled as an RPM on RISC-V.
172 (See the above list of packages, but built from SRPMs)
174 (4c) Recreate the filesystem from RPMs.
176 Distribute an initial bootable binary disk image which is completely
177 built from RPMs (but note, not created by Anaconda).
179 (4d) Continue compiling all other RPMs from @Core.
181 As more packages are compiled, distribute them as RPMs and distribute
182 updated bootable binary disk image.
184 (4e) Declare victory and celebrate!
190 What architecture string to use (eg. in RPM package names)? There are
191 32, 64 and (in theory) 128 bit variants of RISC-V. GNU uses "riscv64".