From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756564AbbAIQfY (ORCPT ); Fri, 9 Jan 2015 11:35:24 -0500 Received: from gw-1.arm.linux.org.uk ([78.32.30.217]:55915 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751659AbbAIQfX (ORCPT ); Fri, 9 Jan 2015 11:35:23 -0500 Date: Fri, 9 Jan 2015 16:35:05 +0000 From: Russell King - ARM Linux To: "Jon Medhurst (Tixy)" Cc: Wang Nan , masami.hiramatsu.pt@hitachi.com, lizefan@huawei.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v20 08/11] ARM: kprobes: enable OPTPROBES for ARM 32 Message-ID: <20150109163505.GS12302@n2100.arm.linux.org.uk> References: <1420457376-77366-1-git-send-email-wangnan0@huawei.com> <1420785456-21900-1-git-send-email-wangnan0@huawei.com> <1420799154.4160.19.camel@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1420799154.4160.19.camel@linaro.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 09, 2015 at 10:25:54AM +0000, Jon Medhurst (Tixy) wrote: > On Fri, 2015-01-09 at 14:37 +0800, Wang Nan wrote: > > + " and r4, sp, #4\n" > > + " sub sp, sp, r4\n" > > +#if __LINUX_ARM_ARCH__ >= 5 > > + " blx r2\n" > > +#else > > + " mov lr, pc\n" > > + " bx r2\n" > > I think the BX instruction is not supported for ARMv4 chips that don't > have Thumb support (e.g. SA110), at least an old ARM ARM I have says BX > is supported on "Version 5 and above, and T variants of version 4". Correct. > Though building assabet_defconfig with kprobes enabled doesn't produce > an error for the BX instruction (!?) Which config are you using? Does it have CONFIG_CPU_32v4 enabled? That should result in "-D__LINUX_ARM_ARCH__=4 -march=armv4" being passed to the compiler (please check with make V=1). -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net.