From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1SwCGM-00070N-2k for barebox@lists.infradead.org; Tue, 31 Jul 2012 13:13:48 +0000 Date: Tue, 31 Jul 2012 15:13:19 +0200 From: Sascha Hauer Message-ID: <20120731131319.GY30009@pengutronix.de> References: <50170C6A.2000101@erwinrol.com> <5017B839.7070806@erwinrol.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <5017B839.7070806@erwinrol.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: barebox-bounces@lists.infradead.org Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: x86 weirdness To: Erwin Rol Cc: barebox@lists.infradead.org Hi Erwin, On Tue, Jul 31, 2012 at 12:49:29PM +0200, Erwin Rol wrote: > Hey x86-asm-experts, Surely you do not mean me ;) > > On 31-7-2012 0:36, Erwin Rol wrote: > > So when I use the memset code the asm looks like this below. As you > can see the memset gets its 3 parameters from the stack (see > comments below in the asm src). But when you look at the location > when memset is called it looks like the caller tries to pass the > parameters in registers. After looking into the Makefile I noticed > the arch/x86/boot/* sources get compiled with -mregparm=3, but the > other sources use normal calling convention. This means code from > arch/x86/boot/* can not call any other barebox functions when they > are not of type void f(void). The file arch/x86/boot/regs.c also > calls memset but it seems the compiler notices that regs.c is 16bit > code and so it inlines a 16bit memset version (I at least don't see > a call function). > > Is there any GCC or LD magic we can use to prevent error like this? > Wouldn't it be better to _not_ change the calling convention in the > Makefile, but mark the functions that need it with __attribute__ ? Maybe it's easier and more straight forward to just use a for-loop here instead of playing magic games with attributes and or flags? Are there more functions affected or is it just memset? Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox