Re: [PATCH v8 02/10] x86/bhi: Make clear_bhb_loop() effective on newer CPUs
From: Borislav Petkov
Date: Thu Mar 26 2026 - 06:25:44 EST
On Thu, Mar 26, 2026 at 01:39:34AM -0700, Pawan Gupta wrote:
> I believe the equivalent for cpu_feature_enabled() in asm is the
> ALTERNATIVE. Please let me know if I am missing something.
Yes, you are.
The point is that you don't want to stick those alternative calls inside some
magic bhb_loop function but hand them in from the outside, as function
arguments.
Basically what I did.
Then you were worried about this being C code and it had to be noinstr... So
that outer function can be rewritten in asm, I think, and still keep it well
separate.
I'll try to rewrite it once I get a free minute, and see how it looks.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette