From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756248Ab0BBOh4 (ORCPT ); Tue, 2 Feb 2010 09:37:56 -0500 Received: from moutng.kundenserver.de ([212.227.17.10]:55271 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753595Ab0BBOhw (ORCPT ); Tue, 2 Feb 2010 09:37:52 -0500 From: Arnd Bergmann To: Christoph Hellwig Subject: Re: [PATCH 4/6] improve sys_personality for compat architectures Date: Tue, 2 Feb 2010 15:36:51 +0100 User-Agent: KMail/1.12.2 (Linux/2.6.33-rc5; KDE/4.3.2; x86_64; ; ) Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, tony.luck@intel.com, ralf@linux-mips.org, kyle@mcmartin.ca, benh@kernel.crashing.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, viro@zeniv.linux.org.uk References: <20100201185607.GD11045@lst.de> In-Reply-To: <20100201185607.GD11045@lst.de> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201002021536.51928.arnd@arndb.de> X-Provags-ID: V01U2FsdGVkX19JkMq72sjrHEaBE+h+Y/LBm2t3W10Xc9s9/Uf CDS1WsfgU37FfsD2nSIXPY70LasdQHznnmrqafWQdaz5SrhJKP 3ZHbjUF8PQNsMr/QgAVXg== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 01 February 2010, Christoph Hellwig wrote: > +/* > + * Get/set the personality. > + * > + * Note that we simply return PER_LINUX even if we actually have a 32-bit > + * task (PER_LINUX32) as this is expected by 32-bit userland. > + */ > SYSCALL_DEFINE1(personality, u_long, personality) > { > u_long old = current->personality; > > if (personality != 0xffffffff) { > + if (personality(old) == PER_LINUX32 && > + personality == PER_LINUX) > + personality = PER_LINUX32; > set_personality(personality); > if (current->personality != personality) > return -EINVAL; > } > > - return (long)old; > + return (long)(old == PER_LINUX32 ? PER_LINUX : old); > } What does this do for a native 64 bit process setting PER_LINUX32? It looks to me like it could never set it back to the original value, or am I missing something here? It's what the arch specific code does already, but it seems a bit strange anyway. Arnd