This page describes how to build V8 for execution on RISC-V hardware or RISC-V QEMU. It is assumed that you have already followed the steps to get the source.
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RISC-V Toolchain¶
Install Prerequisites¶
sudo apt install gawk texinfo zlib1g-dev
Build Toolchain¶
Follow the steps below to install the RISC-V toolchain. There is nothing modified in the standard toolchain, so if you already have this installed, you can skip this step.
$ git clone https://github.com/riscv/riscv-gnu-toolchain
$ cd riscv-gnu-toolchain
$ git submodule update --init --recursive
./configure --prefix=/opt/riscv
sudo make linux -j8
Note -j8 specifies parallel build with 8 processes, and should be adjusted to the number of cores on your machines.
Be sure to add the path to this new toolchain to your path:
export PATH="/opt/riscv/bin:$PATH"
V8 Build¶
Install prerequisites¶
The following script will use apt to install any packages required for building v8. You will need sudo access to install the packages.
cd $V8_ROOT/v8
./build/install-build-deps.sh
Configure toolprefix¶
Make sure you have followed the Patch the Chromium Toolchain step on the Get the Source page.
Before build it , we need apply a The patch.
The patch defines riscv64 toolchain configurations in $V8_ROOT/v8/build/toolchain/linux/BUILD.gn. By default, the toolprefix of gcc_toolchain("riscv64") is set to riscv64-linux-gnu-. If your system uses a different RISC-V toolchain prefix, the setting for toolprefix needs to be manually updated. For instance, if your RISCV toolchain has the prefix of riscv64-unknown-linux-gnu, then make the following changes to $V8_ROOT/v8/build/toolchain/linux/BUILD.gn
gcc_toolchain("riscv64") {
toolprefix = "riscv64-unknown-linux-gnu"
...
Cross-compile v8 as RISC-V binary on an x86-64 Host¶
Configure with GN¶
The following commands build an riscv64 executable for v8 . We use gn to configure the debug build as such:
gn gen out/riscv64.native.debug --args='is_component_build=false is_debug=true target_cpu="riscv64" v8_target_cpu="riscv64" use_goma=false goma_dir="None" treat_warnings_as_errors=false'
If the binary is too large. You can add symbol_level = 1 or symbol_level = 0 to ./out/riscv64.native.debug/arg.gn. If symbol_level is 0, it means there is no debug-symbol in binary. Default value is 2.
Build with Ninja¶
ninja -C out/riscv64.native.debug -j8
Note, -j8 specifies to use 8 cores for the build and should be adjusted for your build machine.
Run on QEMU¶
Download QEMU¶
Clone QEMU:
cd $V8_ROOT/
git clone git@github.com:qemu/qemu.git
cd $V8_ROOT/qemu
git checkout v5.0.0
Install Prerequisites¶
sudo apt-get install libglib2.0-dev libpixman-1-dev
Build QEMU for riscv64¶
./configure --target-list=riscv64-softmmu && make -j 4
sudo make install # Optional
Download Fedora and U-Boot Images¶
From https://dl.fedoraproject.org/pub/alt/risc-v/repo/virt-builder-images/images/, download Fedora-Developer-Rawhide-*.raw.xz as well as the matching Fedora-Developer-Rawhide-*-fw_payload-uboot-qemu-virt-smode.elf:
wget https://dl.fedoraproject.org/pub/alt/risc-v/repo/virt-builder-images/images/Fedora-Developer-Rawhide-20191123.n.0-sda.raw.xz
unxz -k Fedora-Developer-Rawhide-20191123.n.0-sda.raw.xz
wget https://dl.fedoraproject.org/pub/alt/risc-v/repo/virt-builder-images/images/Fedora-Developer-Rawhide-20191123.n.0-fw_payload-uboot-qemu-virt-smode.elf
Run QEMU¶
In the command below, VER is the version number from the files you downloaded above, for example, 20191123.n.0.
Let FEDORA_IMAGE_DIR be the directory that contains Fedora-Developer-Rawhide-20191123.n.0-fw_payload-uboot-qemu-virt-smode.elf and
Fedora-Developer-Rawhide-20191123.n.0-sda.raw (downloaded by following the previous step).
cd <FEDORA_IMAGE_DIR>
export VER=20191123.n.0
qemu-system-riscv64 \
-nographic \
-machine virt \
-smp 4 \
-m 2G \
-kernel Fedora-Developer-Rawhide-${VER}-fw_payload-uboot-qemu-virt-smode.elf \
-object rng-random,filename=/dev/urandom,id=rng0 \
-device virtio-rng-device,rng=rng0 \
-device virtio-blk-device,drive=hd0 \
-drive file=Fedora-Developer-Rawhide-${VER}-sda.raw,format=raw,id=hd0 \
-device virtio-net-device,netdev=usernet \
-netdev user,id=usernet,hostfwd=tcp::3333-:22
Once qemu is brought up, you will see the following prompt:
Welcome to the Fedora/RISC-V disk image
https://fedoraproject.org/wiki/Architectures/RISC-V
Build date: Sat Nov 23 12:47:19 UTC 2019
Kernel 5.4.0-0.rc7.git0.1.1.riscv64.fc32.riscv64 on an riscv64 (ttyS0)
The root password is 'fedora_rocks!'.
root password logins are disabled in SSH starting Fedora 31.
User 'riscv' with password 'fedora_rocks!' in 'wheel' group is provided.
To install new packages use 'dnf install ...'
To upgrade disk image use 'dnf upgrade --best'
If DNS isn’t working, try editing ‘/etc/yum.repos.d/fedora-riscv.repo’.
For updates and latest information read:
https://fedoraproject.org/wiki/Architectures/RISC-V
Fedora/RISC-V
-------------
Koji: http://fedora.riscv.rocks/koji/
SCM: http://fedora.riscv.rocks:3000/
Distribution rep.: http://fedora.riscv.rocks/repos-dist/
Koji internal rep.: http://fedora.riscv.rocks/repos/
fedora-riscv login:
The default root password for this image is fedora_rocks!.
Copy V8 to QEMU¶
Inside the QEMU console, you’ll need to enable root login over ssh with password. Add the following line to /etc/ssh/sshd_config:
PermitRootLogin=yes
Then restart the ssh server:
[root@fedora-riscv ~]# systemctl restart sshd.service
Now, you can use scp from a regular terminal on the same machine (not the qemu terminal) to copy files to the emulated machine. Note that the SSH port of the machine is mapped to 3333.
[joesmith@your-local-terminal] scp -P 3333 $V8_ROOT/v8/out/riscv64.native.debug/d8 $V8_ROOT/v8/out/riscv64.native.debug/snapshot_blob.bin root@localhost:~/.
To log into your QEMU instance from another terminal on the same server, ssh -p 3333 root@localhost.
Run V8 on QEMU¶
Now, you are ready to run d8 inside the qemu console:
[root@fedora-riscv ~]# cat hello.js
console.log("hello, world!");
[root@fedora-riscv ~]# ./d8 hello.js
hello, world!
For more info about Fedora on RISC-V, please visit https://fedoraproject.org/wiki/Architectures/RISC-V/Installing
Script for Developers in China¶
For developers within China, the PLCT lab provides a script to retrieve and run fedora-riscv64 from a local mirror: deploy_riscv64fedora_qemu.sh.
Run this script:
./deploy_riscv64fedora_qemu.sh