Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752597AbWLQN3M (ORCPT ); Sun, 17 Dec 2006 08:29:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751347AbWLQN3M (ORCPT ); Sun, 17 Dec 2006 08:29:12 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:49058 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752598AbWLQN3L (ORCPT ); Sun, 17 Dec 2006 08:29:11 -0500 Subject: Re: V4L2: __ucmpdi2 undefined on ppc From: David Woodhouse To: Kyle McMartin Cc: Mauro Carvalho Chehab , Meelis Roos , Linux Kernel list , linuxppc-dev@ozlabs.org, paulus@samba.org In-Reply-To: <20061214195842.GA14041@athena.road.mcmartin.ca> References: <1166053317.909.19.camel@praia> <20061214195842.GA14041@athena.road.mcmartin.ca> Content-Type: text/plain Date: Sun, 17 Dec 2006 13:29:05 +0000 Message-Id: <1166362145.6714.53.camel@pmac.infradead.org> Mime-Version: 1.0 X-Mailer: Evolution 2.8.2.1 (2.8.2.1-2.fc6.dwmw2.1) Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2372 Lines: 74 On Thu, 2006-12-14 at 14:58 -0500, Kyle McMartin wrote: > I posted a patch to Paul this week to fix this, Hm, I didn't see it on linuxppc-dev. > Since ppc32 can't do a 64bit comparison on its own it seems, gcc > will generate a call to a helper function from libgcc. What other > arches do is link libgcc.a into libs-y, and export the symbol > they want from it. You still get to 'accidentally' do 64-bit arithmetic in-kernel that way though. Might be better just to provide __ucmpdi2, just as we have for the other functions which are required from libgcc It'd be better just to fix the compiler though -- which is in fact what they've done: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25724 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21237 I've applied this as a temporary hack to the Fedora kernel until the compiler is updated there... --- linux-2.6.19.ppc/arch/powerpc/kernel/misc_32.S~ 2006-11-29 21:57:37.000000000 +0000 +++ linux-2.6.19.ppc/arch/powerpc/kernel/misc_32.S 2006-12-17 12:19:48.000000000 +0000 @@ -728,6 +728,27 @@ _GLOBAL(__lshrdi3) or r4,r4,r7 # LSW |= t2 blr +/* + * __ucmpdi2: 64-bit comparison + * + * R3/R4 has 64 bit value A + * R5/R6 has 64 bit value B + * result in R3: 0 for A < B + * 1 for A == B + * 2 for A > B + */ +_GLOBAL(__ucmpdi2) + cmplw r7,r3,r5 # compare high words + li r3,0 + blt r7,2f # a < b ... return 0 + bgt r7,1f # a > b ... return 2 + cmplw r6,r4,r6 # compare low words + blt r6,2f # a < b ... return 0 + li r3,1 + ble r6,2f # a = b ... return 1 +1: li r3,2 +2: blr + _GLOBAL(abs) srawi r4,r3,31 xor r3,r3,r4 --- linux-2.6.19.ppc/arch/powerpc/kernel/ppc_ksyms.c~ 2006-12-15 17:19:56.000000000 +0000 +++ linux-2.6.19.ppc/arch/powerpc/kernel/ppc_ksyms.c 2006-12-17 12:16:54.000000000 +0000 @@ -161,9 +161,11 @@ EXPORT_SYMBOL(to_tm); long long __ashrdi3(long long, int); long long __ashldi3(long long, int); long long __lshrdi3(long long, int); +int __ucmpdi2(uint64_t, uint64_t); EXPORT_SYMBOL(__ashrdi3); EXPORT_SYMBOL(__ashldi3); EXPORT_SYMBOL(__lshrdi3); +EXPORT_SYMBOL(__ucmpdi2); #endif EXPORT_SYMBOL(memcpy); -- dwmw2 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/