Messages in this thread | | | From | Paul Turner <> | Date | Mon, 8 Jan 2018 16:15:51 -0800 | Subject | Re: [PATCH] x86/retpoline: Avoid return buffer underflows on context switch |
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On Mon, Jan 8, 2018 at 2:25 PM, Andi Kleen <ak@linux.intel.com> wrote: >> So pjt did alignment, a single unroll and per discussion earlier today >> (CET) or late last night (PST), he only does 16. > > I used the Intel recommended sequence, which recommends 32. > > Not sure if alignment makes a difference. I can check. > >> Why is none of that done here? Also, can we pretty please stop using >> those retarded number labels, they make this stuff unreadable. > > Personally I find the magic labels with strange ASCII characters > far less readable than a simple number. > > But can change it if you insist. > >> Also, pause is unlikely to stop speculation, that comment doesn't make >> sense. Looking at PJT's version there used to be a speculation trap in >> there, but I can't see that here. > > My understanding is that it stops speculation. But could also > use LFENCE. >
Neither pause nor lfence stop speculation.
> -Andi
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