Re: [PATCH] arm64: fpsimd: Added API to manage fpsimd state inside kernel

[Mark Rutland]

Hi Wooyeon,

There are a *lot* of people Cc' here, many of whomo will find this
irrelevant. Please try to keep the Cc list constrained to a reasonable
number of interested parties.

On Fri, Jun 05, 2020 at 04:30:52PM +0900, Wooyeon Kim wrote:
> From: Wooki Min <wooki.min@xxxxxxxxxxx>
> 
>      This is an patch to use FPSIMD register in Kernel space.
>      It need to manage to use FPSIMD register without damaging it
>      of the user task.
>      Following items have been implemented and added.

Please introduce the problem you are trying to solve in more detail. We
already have kernel_neon_{begin,end}() for kernel-mode NEON; why is that
not sufficient for your needs? Please answer this before considering
other details.

What do you want to use this for?

> 
>      1. Using FPSIMD in ISR (in_interrupt)
> 	It can used __efi_fpsimd_begin/__efi_fpsimd_end
> 	which is already implemented.
> 	Save fpsimd state before entering ISR,
> 	and restore fpsimd state after ISR ends.
> 	For use in external kernel module,
> 	it is declared as EXPORT_SYMBOL.

This patch adds no in-tree modular users of this, so per the usual
conventions, NAK to EXPORT_SYMBOL().

Thanks,
Mark.