Re: [PATCH] m68knommu: remove set_fs()

Christoph Hellwig <[email protected]> Thu, 8 Jul 2021 06:17:37 +0200

Newsgroups	gmane.linux.ports.m68k,gmane.linux.uclinux.devel
Message-ID	<[email protected]>

On Wed, Jul 07, 2021 at 09:14:29PM -0700, Linus Torvalds wrote:
> Except now that I think about it, I worry about getting scheduled away
> *between* the instruction that sets SFC and the one that sets DFC. And
> then switch_to() will save just SFC to the thread-struct. And then
> restore the (new thread) SFC value to _both_ SFC and DFC.

arch/m68k/Kconfig:      select ARCH_NO_PREEMPT if !COLDFIRE

So only coldfire can support kernel preemption, and coldfire never uses
SFC/DFC.