Elastic Metal RV1 guidelines

Boot process

EM-RV1 servers do not support standard UEFI or BIOS boot, therefore the boot process might slightly differ from other servers. At boot, the bootloader expects the eMMC to be partitioned as GPT, and will look for a boot.itb file in the first or second partition. The partition that contains this boot file must be formatted as FAT32.

This boot.itb file is in fact a FIT Image that must contain the following sections:

• kernel: A Linux kernel image.
• fdt: A device tree.
• opensbi: The SBI as defined by RISC-V SBI specification.
• env: A text-based environment file that defines the following keys:
  • usr_bootargs: Command-line arguments to pass to the kernel.
  • usr_has_ramdisk: Set to 1 if we should load the ramdisk from the FIT image.
• ramdisk (optional): A ramdisk image.

The following section will explain in details how to create your own boot FIT image.

Boot a custom kernel

In this section, you will build a boot image based off a close-to-mainline Linux kernel.

Before you start

To complete the actions presented below, you must have:

• Installed an EM-RV1 server with Ubuntu
• Proficient knowledge of Linux systems
• A few hours of availability to build a Linux kernel

1. Connect to your EM-RV1 server using SSH.
2. Install the build dependencies.

   sudo apt update
   sudo apt install -y \
     autoconf bc bison dwarves flex gawk git make \
     libelf-dev libssl-dev \
     u-boot-tools device-tree-compiler
   

3. Clone the projects to build.

   git clone --depth=1 https://github.com/revyos/th1520-linux-kernel.git linux
   git clone https://github.com/revyos/thead-opensbi.git opensbi
   git clone https://github.com/scaleway/em-rv1.git
   

4. Build the Linux kernel.

   cd linux/
   make revyos_defconfig
   # This can take several hours.
   make -j
   sudo make modules_install
   cd ..
   

5. Build OpenSBI.

   cd opensbi/
   make PLATFORM=generic -j
   cd ..
   

6. Build and install the FIT image.

   cd em-rv1/fit/
   # Build the device tree
   cpp \
    -nostdinc \
    -I ../linux/arch/riscv/boot/dts/thead/ \
    -I ../linux/include/ \
    -undef \
    -x assembler-with-cpp \
    em-rv1-c4m16s128-a.dts \
    | dtc -o em-rv1-c4m16s128-a.dtb
   # Build the FIT image
   sudo mv /boot/boot.itb /boot/boot.itb.bak
   sudo mkimage -f em-rv1-c4m16s128-a-boot.its /boot/boot.itb
   cd -
   

7. Reboot the server to load the new kernel.

Update the kernel

Due to hardware specificities, it is not possible to use the kernel provided by major Linux distributions directly on EM-RV1 servers. Instead, we provide a custom upgrade channel. Follow the steps below to update your kernel:

1. Reboot your EM-RV1 server in rescue mode.

2. Log into the machine over SSH using the rescue user.

3. Update the kernel:

   sudo rv1 update-kernel
   

   Note

   If you prefer to run a more recent Linux kernel instead of the vendor-provided kernel, you can append the --tree mainline option.

   Although we do not recommend it, you can also enable support for vector instructions with the --enable-vector flag. Be aware that this feature makes your system vulnerable to the GhostWrite attack and implements an unratified version of RISC-V vector instructions (RVV 0.7.1) which requires specific development efforts.

   For a comprehensive list of options, refer to rv1 update-kernel --help.

4. Wait for the update to complete. This step can take a few minutes.

5. Reboot the server in normal mode.

Android

Remote access

This guide will help you get a remote access on the Android distribution installed on your EM-RV1 server.

Before you start

To complete the actions presented below, you must have:

• Installed Android Platform tools on your local machine
• Installed scrcpy on your local machine
• Installed the Android image on your EM-RV1 server

1. Open a SSH tunnel to the ADB daemon running on your server:

   ssh -L '5555:localhost:5555' root@<your server IP address>
   

   Make sure you keep this session open in the background during the next steps.
2. In a new local shell, connect your local ADB client to the remote daemon through the SSH tunnel you created in the previous step:

   adb connect localhost:5555
   

3. Start a scrcpy session on this ADB session:

   scrcpy -s localhost:5555
   

adb -s localhost:5555 install path/to/app.apk