Hacker News Reader

Cortex R-series and A-series chips seem to be affected. What ARM chips are not affected come from the M-series line. What smartphones use those, or an equivalent permutation?

EDIT: Having done a little reading, I can't find an instance of a notable (even marginally so) smartphone using an M-series chip.

View on HN

Yeah, M-Series aren't made for things like smartphones. They're primarily IoT and Automotive focused, and the M0 and M0+ variants are positioned as 8 and 16-bit microcontroller replacements. Vendors typically don't add DDR SDRAM controllers to their implementations of M-Series cores, so memory is limited to SDR, which would be too small and too slow for a smartphone. Processor speed is also too slow - generally in the 10s to few hundreds of MHz range, with ~300MHz being the fastest for the relatively high-performance Cortex M7.

Cortex A53 and A55 (in-order designs) are not vulnerable to any variant. ARM Ltd. provide details for all of their designs (it's a bit like Swiss cheese, each core is vulnerable to different variants). Thus low/mid-tiers and half of cores in big.LITTLE configuration are safe. The worst is latest gen, Cortex A75, which is vulnerable to all of variants (incl. Meltdown).

It's all in ARM Ltd. report and whitepaper.

Reply on news.ycombinator.com