Re: [PATCH v5 1/3] x86/cpu: Clear feature bits disabled at compile-time

[Borislav Petkov]

On Thu, Feb 12, 2026 at 03:04:44PM -0800, Sohil Mehta wrote:
> Can we just deprecate the "Flags" bits of /proc/cpuinfo at this point?
> 
> No production software can be using this meaningfully.

Before you do, grep glibc sources.

> We have always said that the *absence* of the feature doesn't mean anything.
> The feature could be disabled or the kernel doesn't know about it.
> 
> And now we've realized that the *presence* of the feature in /proc/cpuinfo
> doesn't mean anything either.

How so? The presence means, the kernel has enabled it. See
Documentation/arch/x86/cpuinfo.rst

> Should we come up with a more thought-out mechanism for user space
> feature detection?

No, because it'll be the same crap as what we have now.

This one works ok-ish.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette