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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Q5uho8c111Sif1rjA6es7LKqax+bTf/baHAxUzEgiBs=; b=FMbRlDdYgysPGrHa34rZAUFBBBxVG5hs+NXkOVinZJC9VZ7o93IAcz8RIYDYKf5qJl +73Ku52joTw3zT26BMNH/G4vuo6Zryv6IyfCh0bKiOWKWjYImfJ32CZqRsctG5/jKmWw xnwa/a6AqptADP1hNAUwzh23foXQfZNYCHC9qVZXIsb+wbHyZApHTzrsq31UftoWAYBw LgfmdxOHzri7pFk0ak0H2INt5Wa2YXY4C2fqFVMsNN5Uj4xYiDWoSrCBE1nJGz6qxkEW V3D4WUTtccCcdyWVR3JZqe6462hTIbxd8U0giX/qmeP/9SXQNNQd+WxrQ+7PutdpdMzh s8VQ== X-Gm-Message-State: AOAM530cuab/v9KpNet4QjxbqwrCJDS9SZgMY3S5weZ4S5k02hyJQVoV TCH+GbLTBm+7QHtIOdAYk9A/Z6vUllag9xzVX+f+/Q== X-Google-Smtp-Source: ABdhPJyF1/TvRtGDiGqtJCE9/ZaqS8MWqJmh/44/JnQk8HhLwq5VDQLuH1PjTPWAuAmpVNS/nDZZEqrEYVoucPXQbvA= X-Received: by 2002:a17:906:6959:: with SMTP id c25mr1128516ejs.375.1595448203126; Wed, 22 Jul 2020 13:03:23 -0700 (PDT) MIME-Version: 1.0 References: <20200624203200.78870-1-samitolvanen@google.com> <20200624203200.78870-5-samitolvanen@google.com> <20200624212737.GV4817@hirez.programming.kicks-ass.net> <20200624214530.GA120457@google.com> <20200625074530.GW4817@hirez.programming.kicks-ass.net> <20200625161503.GB173089@google.com> <20200625200235.GQ4781@hirez.programming.kicks-ass.net> <20200625224042.GA169781@google.com> <20200626112931.GF4817@hirez.programming.kicks-ass.net> <20200722135542.41127cc4@oasis.local.home> <20200722184137.GP10769@hirez.programming.kicks-ass.net> <20200722150943.53046592@oasis.local.home> In-Reply-To: <20200722150943.53046592@oasis.local.home> From: Sami Tolvanen Date: Wed, 22 Jul 2020 13:03:12 -0700 Message-ID: Subject: Re: [RFC][PATCH] objtool,x86_64: Replace recordmcount with objtool To: Steven Rostedt X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200722_160325_696465_ED9DBB52 X-CRM114-Status: GOOD ( 15.73 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch , X86 ML , Kees Cook , "Paul E. McKenney" , Kernel Hardening , Peter Zijlstra , Greg Kroah-Hartman , Masahiro Yamada , linux-kbuild , Nick Desaulniers , LKML , clang-built-linux , Josh Poimboeuf , linux-pci@vger.kernel.org, Will Deacon , linux-arm-kernel Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Jul 22, 2020 at 12:09 PM Steven Rostedt wrote: > > On Wed, 22 Jul 2020 20:41:37 +0200 > Peter Zijlstra wrote: > > > > That said, Andi Kleen added an option to gcc called -mnop-mcount which > > > will have gcc do both create the mcount section and convert the calls > > > into nops. When doing so, it defines CC_USING_NOP_MCOUNT which will > > > tell ftrace to expect the calls to already be converted. > > > > That seems like the much easier solution, then we can forget about > > recordmcount / objtool entirely for this. > > Of course that was only for some gcc compilers, and I'm not sure if > clang can do this. > > Or do you just see all compilers doing this in the future, and not > worrying about record-mcount at all, and bothering with objtool? Clang appears to only support -mrecord-mcount and -mnop-mcount for s390, so we still need recordmcount / objtool for x86. Sami _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel