linux-kernel - Re: [PATCH] x86: pad assembly functions with INT3

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Message-ID: <20180515065405.GA31240@gmail.com>
Date:   Tue, 15 May 2018 08:54:05 +0200
From:   Ingo Molnar <mingo@...nel.org>
To:     hpa@...or.com
Cc:     David Laight <David.Laight@...LAB.COM>,
        'Alexey Dobriyan' <adobriyan@...il.com>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>
Subject: Re: [PATCH] x86: pad assembly functions with INT3


* hpa@...or.com <hpa@...or.com> 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