Re: [PATCH 1/2] sparc32,leon: Build with -mcpu=leon3 for SPARC_LEON

[David Miller]

From: Andreas Larsson <andreas@xxxxxxxxxxx>
Date: Tue, 14 Nov 2017 15:03:42 +0100

> Apart from using LEON3 instruction timing it allows for usage of the
> CASA instruction.
> 
> Signed-off-by: Andreas Larsson <andreas@xxxxxxxxxxx>

Up until this point the LEON kconfig option is largely passive.

All of the sparc_cpu_type logic drives what parts of the kernel are
used based upon the run-time detected cpu type.

But with this change, it completely breaks the 32-bit sparc kernel
on any non-Leon processor.

I wish you would reconsider this approach, and instead do hardcoded
assembler instruction opcodes to use "casa" in assembler, and run
time detect CAS support in the 32-bit cpu.

Thank you.