Try ANGEL, an in-browser RISC-V ISA Simulator that boots Linux

You can try out RISC-V without even leaving your browser! Click here to launch ANGEL.

Install QEMU, a fast ISA Simulator

Prereqs:

• Linux or Mac OSX
• C compiler (gcc)

Download the QEMU Source, either as a zip from Github, or using git:

$ git clone https://github.com/ucb-bar/riscv-qemu.git

Now, cd into the riscv-qemu directory and run the following. You may exclude the prefix argument, in which case you'll find the qemu-system-riscv binary in the riscv-softmmu directory after building. Otherwise, replace [Location to place binaries] with the location in which you'd like riscv-qemu to be installed.

$ ./configure --target-list=riscv-softmmu --prefix=[Location to place binaries]
$ make
$ make install # only run this if you specified a prefix above

Next, you'll need to download two more files, the precompiled riscv-linux kernel and a disk image with the filesystem:

• riscv-linux kernel (vmlinux): Download
• rootfs disk image (root.bin): Download

At this point, ensure that the prefix location you specified above is on your path. If you opted not to include the prefix argument, enter into the riscv-softmmu directory, where the qemu-system-riscv binary is located. Once you've downloaded both of the above files, we can go ahead and boot linux:

$ qemu-system-riscv -hda [Location of root.bin] -kernel [Location of vmlinux] -nographic

You should see the linux boot messages fly by and will eventually come to an ash shell prompt:

...
init started: BusyBox v1.22.1 (2014-07-19 16:30:20 PDT)
starting pid 18, tty '': '/bin/busybox mount -t proc proc /proc'
starting pid 19, tty '': '/bin/busybox mount -t tmpfs tmpfs /tmp'
starting pid 20, tty '': '/bin/busybox mount -o remount,rw /dev/htifbd0 /'
starting pid 21, tty '': '/bin/busybox --install -s'
starting pid 22, tty '/dev/console': '-/bin/ash '
BusyBox v1.22.1 (2014-07-19 16:30:20 PDT) built-in shell (ash)
Enter 'help' for a list of built-in commands.

/ #

Congratulations! At this point you've booted Linux on a simulated RISC-V system. To exit the system cleanly, you should issue the halt command inside the simulated system, and then hit Ctrl-a x:

$ halt -f
Hit Ctrl-a x to exit qemu

If you'd like to learn more about riscv-qemu, see the Download page.

Build your own RISC-V Computer with a Zybo or ZedBoard

How it works

Both the ZedBoard and the Zybo board contain Xilinx Zynq chips with an ARM processor tied to some programmable logic. We'll use the ARM core to bootstrap the RISC-V Rocket Core that we'll run on the programmable logic. Once we've started the RISC-V core, the ARM chip will simply act to emulate devices on the Host-Target Interface Bus (HTIF), like consoles and disks, while the Rocket Core takes care of all the heavy lifting.

You can obtain a Zybo or ZedBoard from various distributors online. From our experience, academic users can buy a Zybo for $125 or a ZedBoard for around $320.

Instructions

1) Connect the necessary cables to your board

If you're using the Zybo, you can either use Ethernet + USB or just USB

If you're using the ZedBoard, you should connect the power and either the USB or the Ethernet

2) Download the appropriate package

Download the appropriate package below, unzip it, and place the contents on the root of your SD Card

Zybo RISC-V Getting Started Pack

ZedBoard RISC-V Getting Started Pack

Once you've done this, the file structure on your SD Card should match the following:

SD_ROOT/
|-> riscv/
    |-> root.bin
    |-> vmlinux
|-> boot.bin
|-> devicetree.dtb
|-> uImage
|-> uramdisk.image.gz

3) Login to the ARM System:

Insert the (micro)SD card into your Zybo/ZedBoard. At this point you have two options for logging in:

1) USB-UART

To connect over usb, do the following (the device name following tty. may vary):

$ screen /dev/tty.usbserial-210279575138B 115200,cs8,-parenb,-cstopb

2) Telnet

You may also connect over telnet using ethernet. The default IP address is 192.168.192.5:

$ telnet 192.168.192.5

In either case, you'll eventually be prompted to login to the ARM system. Both the username and password are root.

4) Start Linux on the RISC-V Rocket Core

Once you're in, you'll need to mount the sd card so that we can access the files necessary to boot linux on the Rocket core. Do the following:

$ mkdir /sdcard
$ mount /dev/mmcblk0p1 /sdcard

Finally, we can go ahead and boot linux on the Rocket core:

$ ./fesvr-zedboard +disk=/sdcard/riscv/root.bin /sdcard/riscv/vmlinux

You should see the linux boot messages fly by and will eventually come to an ash shell prompt:

...
init started: BusyBox v1.22.1 (2014-07-19 16:30:20 PDT)
starting pid 18, tty '': '/bin/busybox mount -t proc proc /proc'
starting pid 19, tty '': '/bin/busybox mount -t tmpfs tmpfs /tmp'
starting pid 20, tty '': '/bin/busybox mount -o remount,rw /dev/htifbd0 /'
starting pid 21, tty '': '/bin/busybox --install -s'
starting pid 22, tty '/dev/console': '-/bin/ash '
BusyBox v1.22.1 (2014-07-19 16:30:20 PDT) built-in shell (ash)
Enter 'help' for a list of built-in commands.

/ #

Congratulations! At this point you've booted Linux on a simulated RISC-V system. If you'd like to learn more about the RISC-V FPGA Infrastructure, see the Download page.