From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756341AbcIVKVk (ORCPT ); Thu, 22 Sep 2016 06:21:40 -0400 Received: from ozlabs.org ([103.22.144.67]:46900 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756025AbcIVKVh (ORCPT ); Thu, 22 Sep 2016 06:21:37 -0400 From: Michael Ellerman To: Akshay Adiga , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Cc: anton@samba.org, Akshay Adiga Subject: Re: [PATCH] Work around for enabling CONFIG_CMDLINE on ppc64le In-Reply-To: <1474525245-10739-1-git-send-email-akshay.adiga@linux.vnet.ibm.com> References: <1474525245-10739-1-git-send-email-akshay.adiga@linux.vnet.ibm.com> User-Agent: Notmuch/0.21 (https://notmuchmail.org) Date: Thu, 22 Sep 2016 20:21:29 +1000 Message-ID: <87d1jw8cba.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Akshay Adiga writes: > Observed that boot arguments (passed as CONFIG_CMDLINE) are not being > picked up by kernel while using gcc-ppc64-linux-gnu v5.4.0 and v6.1.1. > While it works as expected with v5.3.1 . > > Found that in init/main.c in setup_command_line() the pointers passed to > strcpy() is messed up. Hi Akshay, Thanks for debugging this. > The problem goes away when compiler optimization is restricted to -O1. > diff --git a/init/main.c b/init/main.c > index a8a58e2..4259c42 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -358,7 +358,13 @@ static inline void smp_prepare_cpus(unsigned int maxcpus) { } > * parsing is performed in place, and we should allow a component to > * store reference of name/value for future reference. > */ > -static void __init setup_command_line(char *command_line) > +static void __init > +#ifdef CONFIG_PPC64 > + #if GCC_VERSION > 50301 > + __attribute__((optimize("-O1"))) > + #endif > +#endif > + setup_command_line(char *command_line) > { > saved_command_line = > memblock_virt_alloc(strlen(boot_command_line) + 1, 0); But I can't merge that patch. Our options are one or both of: - get GCC fixed and backport the fix to the compilers we care about. - blacklist the broken compiler versions. Is there a GCC bug filed for this? cheers