On 27 August 2018 at 16:53, Theodore Y. Ts'o [off-list ref] wrote:

On Mon, Aug 27, 2018 at 01:02:41PM +0200, Ard Biesheuvel wrote:

quoted

While this is not known to cause performance issues, calling a table based
time variant implementation with a non-negligible D-cache footprint (8 KB)
is wasteful in any case, and now that the crc32 instructions have been made
mandatory in the architecture, let's wire them up into the core crc routines.

Stupid question --- are there any arm64 SOC's out there which do *not*
have the crc32 instructions?  Presumably there won't be in the future,
because it's now mandatory --- but where there any in the past?

Yes, the APM Xgene for instance.