Arm Expands Speculative SSBS Workaround With More CPU Cores Being Affected

[phoronix]

Phoronix: Arm Expands Speculative SSBS Workaround With More CPU Cores Being Affected

Back in May there were Linux kernel patches posted as a workaround for Arm CPU errata around the Speculative Store Bypass (SSB) handling. Initially this workaround was just noted as the Cortex-X4 and Neoverse-V3 as being affected, but now it turns out many more exciting Arm processor cores are impacted...

https://www.phoronix.com/news/Arm-SSBS-Linux-More-CPUs

[pWe00Iri3e7Z9lHOX2Qx]

The expanded core list will include a ton of recent high end and midrange devices.

[nuetzel]

Backport underway.

[rob-tech]

I'm assuming this will mean many recent high end Android phones are about to become much slower.

[edxposed]

I'm assuming this will mean many recent high end Android phones are about to become much slower.

Most Android devices don't usually update kernel.

[Developer12]

Most Android devices don't usually update kernel.

most android devices don't update, period. apps might get a refresh but it stays the same buggy, vulnerable system forever.

[aviallon]

most android devices don't update, period. apps might get a refresh but it stays the same buggy, vulnerable system forever.

Well, some parts do get updated if they use a GKI.

[ayumu]

TL;DR ARM lose the performance they had by cheating with unsafe speculation.

[Developer12]

Well, some parts do get updated if they use a GKI.

That helps a little but is far from a panacea. The only thing it does is try to move some SoC and device-specific bits into modules to make it slightly easier to replace the main kernel image.

It doesn't really help with the larger bucket-brigade that is getting mainline kernels down to user devices. Most devices aren't supported long enough for a new kernel to make it from mainline all the way to device manufacturer.

The closest thing to a workable solution has been postmarketOS getting support for every device upstreamed into the mainline kernel itself, so that freshly released kernels can pretty much be directly cloned, compiled, and flashed to the device.

[AkulaMD]

Any estimated real world performance penalty?