Re: [PATCH] x86: pad assembly functions with INT3

From: hpa
Date: Tue May 15 2018 - 03:00:18 EST


On May 14, 2018 11:54:05 PM PDT, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
>
>* hpa@xxxxxxxxx <hpa@xxxxxxxxx> wrote:
>
>> > I guess it won't try to speculatively execute the 'pad'
>instructions - but you
>> > can never really tell!
>> >
>> > David
>>
>> The CPU doesn't speculate down past an unconditional control
>transfer. Doing so
>> would be idiotic.
>
>I think, when it comes to speculative execution, our general
>expectation that CPUs
>don't do idiotic things got somewhat weakened in the past year or so
>...
>
>Thanks,
>
> Ingo

Sort-of-kind-of... the things that have cropped up were reasonable consequences of designing under a set of assumptions which turned out to be incorrect. Speculating through an unconditional control transfer did not make sense under those assumptions either.
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