Re: [RFC 0/2] RISC-V: A proposal to add vendor-specific code

[Arnd Bergmann]

On 11/5/18, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> On Mon, Nov 05, 2018 at 02:58:07PM +0800, Vincent Chen wrote:
>> Many thanks for kinds of comments. I quickly synthesize the comments and
>> list them as below.
>> 1. The kernel image shall include all vendor-specific code.
>
> I fundamentally disagree with thisâ and think it should be the contrary.
>
> 1. The kernel shall support no vendor specific instructions whatsoever,
> period.

I think what was meant above is

1. If a vendor extension requires kernel support, that support
must be able to be built into a kernel image without breaking support
for CPUs that do not have that extension, to allow building a single
kernel image that works on all CPUs.

       Arnd