RISC-V support in Android just got a big setback

Back in early 2023, Google introduced that it was engaged on enabling support for the RISC-V structure in Android. RISC-V is an open instruction set structure that’s grown in recognition in latest years since {hardware} makers don’t have to pay a licensing payment to construct RISC-V chips. Some Android gadgets already ship with chipsets based mostly on RISC-V, although these chipsets usually run one thing apart from Android and act as a co-processor to the gadget’s principal, usually Arm-based processor.

Late final 12 months, chip maker Qualcomm introduced that it was designing a wearable chipset based mostly on RISC-V and that this chipset would run on Google’s Android-based Wear OS platform. Once launched, these Wear OS smartwatches can be the primary industrial RISC-V {hardware} to run a Google-certified Android construct. To make that occur, although, Google should commit a lot of engineering sources to make Android — and its underlying Linux kernel fork — boot on RISC-V {hardware}. Google has already finished a lot  of the work to allow RISC-V support in Android, although there’s fairly a bit of labor nonetheless forward.

Although Google has proven vital progress in latest weeks in bettering RISC-V support in Android, plainly we’re nonetheless fairly a bit away from seeing RISC-V {hardware} operating licensed builds of Android. Earlier as we speak, a Senior Staff Software Engineer at Google who, based on their LinkedIn, leads the Android Systems Team and works on Android’s Linux kernel fork, submitted a sequence of patches to AOSP that “remove ACK’s support for riscv64.” The description of those patches states that “support for risc64 GKI kernels is discontinued.”

ACK stands for Android Common Kernel and refers back to the downstream branches of the official kernel.org Linux kernels that Google maintains. The ACK is mainly Linux plus some “patches of interest to the Android community that haven’t been merged into mainline or Long Term Supported (LTS) kernels.” There are a number of ACK branches, together with android-mainline, which is the first growth department that’s forked into “GKI” kernel branches that correspond to a explicit mixture of supported Linux kernel and Android OS model. GKI stands for Generic Kernel Image and refers to a kernel that’s constructed from one in all these branches. Every licensed Android gadget ships with a kernel based mostly on one in all these GKI branches, as Google presently doesn’t certify Android gadgets that ship with a mainline Linux kernel construct.

Since these patches take away RISC-V kernel support, RISC-V kernel construct support, and RISC-V emulator support, any firms seeking to compile a RISC-V construct of Android proper now would wish to create and preserve their very own fork of Linux with the requisite ACK and RISC-V patches. Given that Google presently solely certifies Android builds that ship with a GKI kernel constructed from an ACK department, which means we seemingly gained’t see licensed builds of Android on RISC-V {hardware} anytime quickly.

Our preliminary interpretation of those patches was that Google was getting ready to kill off RISC-V support in Android since that was the obvious conclusion. However, a spokesperson for Google instructed us this:

Android will proceed to support RISC-V. Due to the fast fee of iteration, we aren’t prepared to offer a single supported picture for all distributors. This explicit sequence of patches removes RISC-V support from the Android Generic Kernel Image (GKI).

While the corporate’s assertion doesn’t go into element concerning the rationale behind this resolution, it’s good to get affirmation that RISC-V support in Android isn’t being killed off fully. Still, the assertion alludes to the truth that there’s nonetheless a ton of labor that must be finished earlier than Android is prepared for RISC-V. Even as soon as it’s prepared, Google might want to redo the work so as to add RISC-V support in the kernel anyway. At the very least, Google’s resolution seemingly signifies that we would want to attend even longer than anticipated to see industrial Android gadgets operating on a RISC-V chip.