On Tue, Dec 08, 2020 at 09:53:11PM +0100, Arnd Bergmann wrote: > I wonder if this is something we should address in the kernel, and make > the behavior in compat mode resemble native 32-bit kernels more closely. > > I think in general we should give as much incentive as possible for > using 64-bit kernels even when running legacy user space, in > particular as the 32-bit kernel is also missing some pieces for > running 32-bit user space on 64-bit hardware. > > Right, most importantly, the ones that do not work include > > - ThunderX > - ThunderX2 > - Apple M1 > > while the ones that do have aarch32 mode include > > - All Ampere servers > - Amazon EC2 > - NXP LX2160, as used in Solidrun LX2K machines > - All other Cortex-A72 and A76 based servers
But does aarch32 mode imply full support for armv4 instructions? armhf at armv7 should be fine I would think, but is armel still v4 or did it move to v5? I can't remember. At least it appears the kernel has options for emulating things like SWP and SWPB if they are missing. Perhaps the future for armhf and even armel isn't totally hopeless. -- Len Sorensen
