Running/building an 32 bits kernel on A53 CPU?

[Joakim Tjernlund]

On Fri, 2021-10-29 at 10:32 +0000, Joakim Tjernlund wrote:
> On Fri, 2021-10-29 at 11:09 +0100, Catalin Marinas wrote:
> > On Fri, Oct 29, 2021 at 08:27:35AM +0000, Joakim Tjernlund wrote:
> > > In order to reduce RAM usage we are wondering if running an 32 bits
> > > kernel on ARM A53 CPU is a good idea?
> > 
> > No. Really.
> > 
> > What's the RAM size on your SoC?
> 
> 32MB + 4MB SRAM
> 
> > 
> > > Is it possible to build such a kernel? If so, how to go about it?
> > > Should one use ARCH=arm and a 32 bits toolchain or
> > > ARCH=arm64 and 64 bits toolchain and adding 32 bits compile options?
> > 
> > If you want a 32-bit kernel, you'd have to use ARCH=arm and a 32-bit
> > toolchain. This would give you an ARMv7 kernel that can run on ARMv8
> > hardware. But you'd miss errata workarounds for example and any other
> > features that come with ARMv8.

Anything else you can think of why 32 bits kernel is a bad idea?
I do wonder why 64 bits A53 enforces SMP? I only have one core in my HW(custom ASIC)

   Jocke
>