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[209.85.167.47]) by smtp.gmail.com with ESMTPSA id v1sm408919lfg.13.2019.02.25.09.34.33 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 25 Feb 2019 09:34:34 -0800 (PST) Received: by mail-lf1-f47.google.com with SMTP id g2so7490961lfh.11 for ; Mon, 25 Feb 2019 09:34:33 -0800 (PST) X-Received: by 2002:a19:c744:: with SMTP id x65mr1535829lff.148.1551116073198; Mon, 25 Feb 2019 09:34:33 -0800 (PST) MIME-Version: 1.0 References: <20190225124330.613028745@infradead.org> <20190225125232.191698923@infradead.org> <20190225161234.GM32477@hirez.programming.kicks-ass.net> <20190225171531.GD32534@hirez.programming.kicks-ass.net> In-Reply-To: <20190225171531.GD32534@hirez.programming.kicks-ass.net> From: Linus Torvalds Date: Mon, 25 Feb 2019 09:34:17 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 5/6] objtool: Add UACCESS validation To: Peter Zijlstra Cc: Andy Lutomirski , Thomas Gleixner , "H. Peter Anvin" , Julien Thierry , Will Deacon , Ingo Molnar , Catalin Marinas , James Morse , valentin.schneider@arm.com, Brian Gerst , Josh Poimboeuf , Andrew Lutomirski , Borislav Petkov , Denys Vlasenko , LKML 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 Mon, Feb 25, 2019 at 9:15 AM Peter Zijlstra wrote: > > Ah, so the thing we need for inline-asm is %=, but Linus didn't like it: Well, to be fair, I also didn't like the random big numbers. I think that inline asm that has local labels should just use simple enumeration, and always use the direction suffix to make those local labels be unambiguous. Now, there are cases where we may not be able to do that, because we have internal macros within the asm that _also_ wants to do its own numbers. This isn't such a case. For that case, you might actually want to use a fancy "get me a unique number and prefix", but it should be seen as the exception rather than the first solution, because the code starts looking really random. Linus