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[209.85.208.181]) by smtp.gmail.com with ESMTPSA id e82sm409455lfg.34.2018.11.29.09.35.27 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 29 Nov 2018 09:35:28 -0800 (PST) Received: by mail-lj1-f181.google.com with SMTP id l15-v6so2487795lja.9 for ; Thu, 29 Nov 2018 09:35:27 -0800 (PST) X-Received: by 2002:a2e:2416:: with SMTP id k22-v6mr1886754ljk.80.1543512927326; Thu, 29 Nov 2018 09:35:27 -0800 (PST) MIME-Version: 1.0 References: <20181126160217.GR2113@hirez.programming.kicks-ass.net> <20181126171036.chcbmb35ygpxziub@treble> <20181126175624.bruqfbkngbucpvxr@treble> <20181126200801.GW2113@hirez.programming.kicks-ass.net> <20181126212628.4apztfazichxnt7r@treble> <20181127084330.GX2113@hirez.programming.kicks-ass.net> <20181129094210.GC2131@hirez.programming.kicks-ass.net> <20181129143853.GO2131@hirez.programming.kicks-ass.net> <20181129163342.tp5wlfcyiazwwyoh@treble> <0A629D30-ADCF-4159-9443-E5727146F65F@amacapital.net> <20181129121307.12393c57@gandalf.local.home> In-Reply-To: <20181129121307.12393c57@gandalf.local.home> From: Linus Torvalds Date: Thu, 29 Nov 2018 09:35:11 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 4/4] x86/static_call: Add inline static call implementation for x86-64 To: Steven Rostedt Cc: Andy Lutomirski , Josh Poimboeuf , Peter Zijlstra , Andrew Lutomirski , "the arch/x86 maintainers" , Linux List Kernel Mailing , Ard Biesheuvel , Ingo Molnar , Thomas Gleixner , mhiramat@kernel.org, jbaron@akamai.com, Jiri Kosina , David.Laight@aculab.com, bp@alien8.de, julia@ni.com, jeyu@kernel.org, Peter Anvin Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 29, 2018 at 9:13 AM Steven Rostedt wrote: > > No, we really do need to sync after we change the second part of the > command with the int3 on it. Unless there's another way to guarantee > that the full instruction gets seen when we replace the int3 with the > finished command. Making sure the call instruction is aligned with the I$ fetch boundary should do that. It's not in the SDM, but neither was our current behavior - we were/are just relying on "it will work". Linus