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[46.139.12.213]) by smtp.gmail.com with ESMTPSA id m17-v6sm12529709wrh.3.2018.05.14.23.54.07 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 14 May 2018 23:54:07 -0700 (PDT) Date: Tue, 15 May 2018 08:54:05 +0200 From: Ingo Molnar To: hpa@zytor.com Cc: David Laight , 'Alexey Dobriyan' , "tglx@linutronix.de" , "mingo@redhat.com" , "linux-kernel@vger.kernel.org" , "x86@kernel.org" Subject: Re: [PATCH] x86: pad assembly functions with INT3 Message-ID: <20180515065405.GA31240@gmail.com> References: <20180507213755.GA32406@avx2> <20fb84fd5eef4c45b2d38d0290235d5d@AcuMS.aculab.com> <5c6762fe-5cbe-42ed-ac4e-a7144b8ef7ad@zytor.com> <83866d054b27419c9d9dd97d9c66c3de@AcuMS.aculab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * hpa@zytor.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