From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: Re: [PATCH v3 04/22] x86/doublefault: Make memmove() notrace/NOKPROBE Date: Wed, 19 Feb 2020 10:36:14 -0500 Message-ID: <20200219103614.2299ff61@gandalf.local.home> References: <20200219144724.800607165@infradead.org> <20200219150744.604459293@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mail.kernel.org ([198.145.29.99]:42162 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726645AbgBSPgS (ORCPT ); Wed, 19 Feb 2020 10:36:18 -0500 In-Reply-To: <20200219150744.604459293@infradead.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, mingo@kernel.org, joel@joelfernandes.org, gregkh@linuxfoundation.org, gustavo@embeddedor.com, tglx@linutronix.de, paulmck@kernel.org, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, luto@kernel.org, tony.luck@intel.com, frederic@kernel.org, dan.carpenter@oracle.com, mhiramat@kernel.org On Wed, 19 Feb 2020 15:47:28 +0100 Peter Zijlstra wrote: > --- a/arch/x86/lib/memcpy_32.c > +++ b/arch/x86/lib/memcpy_32.c > @@ -21,7 +21,7 @@ __visible void *memset(void *s, int c, s > } > EXPORT_SYMBOL(memset); > > -__visible void *memmove(void *dest, const void *src, size_t n) > +__visible notrace void *memmove(void *dest, const void *src, size_t n) > { > int d0,d1,d2,d3,d4,d5; > char *ret = dest; > @@ -207,3 +207,8 @@ __visible void *memmove(void *dest, cons > > } > EXPORT_SYMBOL(memmove); Hmm, for things like this, which is adding notrace because of a single instance of it (although it is fine to trace in any other instance), it would be nice to have a gcc helper that could call "memmove+5" which would skip the tracing portion. -- Steve