Re: [RFC][PATCH] x86,ibt: Use UDB instead of 0xEA

[Peter Zijlstra]

On Fri, Aug 15, 2025 at 11:43:11AM +0100, Andrew Cooper wrote:

> >> I've had to use cs prefixed jcc.d32, because our older toolchains don't
> >> like the ,pn notation.
> > And then I forgot to move that cs prefix around in the bhi1 case...
> > fixed that.
> 
> Dare I ask what ,pn notation is?  It's not only the older toolchains
> that don't know it :)

Some fancy notation for the CS/DS branch hints.

CS Jcc, decodes to Jcc,pn for non-taken
DS Jcc, decodes to Jcc,pt for taken