Re: [RFC PATCH 0/15] x86: Remove support for TSC-less and CX8-less CPUs

[H. Peter Anvin]

On May 5, 2025 1:53:04 AM PDT, "Maciej W. Rozycki" <macro@xxxxxxxxxxx> wrote:
>On Fri, 25 Apr 2025, Ingo Molnar wrote:
>
>>  > I really get the feeling that it's time to leave i486 support behind.
>>  > There's zero real reason for anybody to waste one second of
>>  > development effort on this kind of issue.
>> 
>> This series increases minimum kernel support features to include TSC and
>> CX8 (CMPXCHG8B) hardware support, which removes 486 (and derivatives) support
>> and early-586 (and derivatives) support.
>
> FWIW I'm not happy about that at the very least because this will prevent 
>me from using my 486 box for EISA defxx driver maintenance.  What exactly 
>is the problem with 486?
>
> I know the lack of TSC has security implications, but don't use the 
>machine in a way for which it would be an issue and I don't expect anyone 
>doing otherwise.  We have non-x86 platforms that lack a high-resolution 
>timer and nobody's going to drop them.
>
> We also have platforms that lack atomics, let alone double-precision ones 
>and they're fine too, so why is x86 different?
>
>  Maciej

Why is x86 different? Because it is a tightly integrated platform with code shared across a very large number of generations, without "silly embedded nonsense hacks."

I think if you have a use case, you need to speak up about it, rather than for people to guess.