From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752418Ab2BTGWP (ORCPT ); Mon, 20 Feb 2012 01:22:15 -0500 Received: from e32.co.us.ibm.com ([32.97.110.150]:40416 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751981Ab2BTGWN (ORCPT ); Mon, 20 Feb 2012 01:22:13 -0500 Date: Mon, 20 Feb 2012 11:38:25 +0530 From: Srikar Dronamraju To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, jkenisto@us.ibm.com, a.p.zijlstra@chello.nl, ananth@in.ibm.com, anton@redhat.com, masami.hiramatsu.pt@hitachi.com, acme@infradead.org, oleg@redhat.com, tglx@linutronix.de, mingo@elte.hu, Benjamin Herrenschmidt , Josh Stone Cc: linux-tip-commits@vger.kernel.org Subject: Re: [tip:perf/uprobes] uprobes/core: Clean up, refactor and improve the code Message-ID: <20120220060825.GA22680@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12022006-3270-0000-0000-0000042A09F3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > - remove unnecessary volatile volatiles were added because of warnings thrown by gcc-4.6. Please see below. > > - restructure comment blocks to make them more uniform and > more readable in general > ... > diff --git a/arch/Kconfig b/arch/Kconfig > index 284f589..cca5b54 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -66,13 +66,19 @@ config OPTPROBES > depends on !PREEMPT > > config UPROBES > - bool "User-space probes (EXPERIMENTAL)" > + bool "Transparent user-space probes (EXPERIMENTAL)" > depends on ARCH_SUPPORTS_UPROBES > default n > help > - Uprobes enables kernel subsystems to establish probepoints > - in user applications and execute handler functions when > - the probepoints are hit. > + Uprobes is the user-space counterpart to kprobes: they > + enable instrumentation applications (such as 'perf probe') > + to establish unintrusive probes in user-space binaries and > + libraries, by executing handler functions when the probes > + are hit by user-space applications. > + > + ( These probes come in the form of single-byte breakpoints, One nit: In some architectures like powerpc, the breakpoints arent single-byte. > + managed by the kernel and kept transparent to the probed > + application. ) > > If in doubt, say "N". > > > #ifdef CONFIG_X86_64 > -static volatile u32 good_insns_64[256 / 32] = { > +static u32 good_insns_64[256 / 32] = { The volatiles were added to arch/x86/kernel/kprobes.c because of commit 7115e3fcf45 and 315eb8a2a1b. The volatiles are required because gcc 4.6 gave a warning about the asm operand for test_bit. So the same were added to arch/x86/kernel/uprobes.c. -- Thanks and Regards Srikar