Booting our RISC-V images

Thanks in large part to the hard work by X512 and everyone developing on Haiku, our nightly RISCV64 images are now functional.

RISC-V marks Haiku's first functional non-Intel/x86 port!

What is RISC-V?

RISC-V is a modern, fully open CPU instruction set[1] which can be implemented, customized, extended, and sold without royalties. Designs exist for a 32-bit, 64-bit, and even a 128-bit processor design.

You can emulate RISC-V in qemu[1], design your own CPU and synthesize it for an FPGA[2], or you can purchase a commercially built and designed computer with a RISC-V processor[3].

Why not ARM?

Haiku developers are continuing to work on ARM and ARM64 ports of Haiku, RISC-V just finished first :-)

Running nightly RISCV64 images in qemu


{{< alert-info "Beware of bugs" "There are multiple lingering bugs (#17379[1], #17380[2] in RISCV64 Haiku running under QEMU. If you don't make it to the desktop, try again.">}}

To boot Haiku in qemu (qemu-system-riscv64), you'll need the following:

- qemu 6.0.0 or later

- Nightly riscv64 Haiku image[1] (hrev55624 or later)

- u-boot binary for qemu riscv64[2]

Once you have the above two items, then booting Haiku is as easy as running the following command:

qemu-system-riscv64 -M virt -m 1G -device ati-vga -kernel u-boot.bin \
	-drive file=haiku-mmc.image,format=raw,if=virtio \
	-usb -device usb-ehci,id=echi -device usb-kbd -device usb-tablet

- You can watch technical serial output via ```view->serial0```

- The eventual Haiku desktop will be available via ```view->ati-vga```

Running nightly RISCV64 images on the SiFive Unmatched

{{< alert-info "Update: Working versions" "riscv64 was broken after our merge of GCC 11. hrev55697 is currently the last image to boot to a desktop until this regression is repaired." >}}

To boot Haiku on the SiFive unmatched, you will need the following:

- SiFive Unmatched board[1]

• A Radeon HD graphics card which works with our radeon_hd driver * [SD Card prepared as a "u-boot uefi bios"](https://git.haiku-os.org/haiku/tree/3rdparty/kallisti5/unmatched-uboot.sh) * [Nightly riscv64 Haiku image](https://download.haiku-os.org/nightly-images/riscv64/) (between hrev55624 and hrev55697) written to a USB Flash drive * ```dd if=haiku-mmc.image of=/dev/sdXX bs=4M```

{{< alert-info "Serial Debugging" "In the event of trouble, attaching a Micro-USB cable to the Unmatched allows you to see serial output during startup. (minicom, 115200 8N1, no flow control)" >}}

Once you have all of the requirements above, the following process will get you booted into Haiku:

1. Plug the SD Card into the SiFive Unmatched 2. Plug the USB Flash drive into the SiFive Unmatched 3. Power on the SiFive Unmatched. You should be greeted with a desktop within a minute or two

Wrapup

Overall, RISC-V offers an exciting opportunity for us to grow our non-x86 architecture support.

A lot of work still remains on RISC-V including support for SMP (multi-processor), however this is a massive first step.