From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755417AbYHFKhF (ORCPT ); Wed, 6 Aug 2008 06:37:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761849AbYHFKgv (ORCPT ); Wed, 6 Aug 2008 06:36:51 -0400 Received: from mta23.gyao.ne.jp ([125.63.38.249]:48486 "EHLO mx.gate01.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1761836AbYHFKgt (ORCPT ); Wed, 6 Aug 2008 06:36:49 -0400 Date: Wed, 6 Aug 2008 19:36:00 +0900 From: Paul Mundt To: David Howells , Andrew Morton , linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/3] binfmt_elf_fdpic: Convert initial stack alignment to arch_align_stack() Message-ID: <20080806103600.GB5194@linux-sh.org> Mail-Followup-To: Paul Mundt , David Howells , Andrew Morton , linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org References: <20080806103458.GE2610@linux-sh.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080806103458.GE2610@linux-sh.org> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org binfmt_elf_fdpic seems to have grabbed a hard-coded hack from an ancient version of binfmt_elf in order to try and fix up initial stack alignment on multi-threaded x86, which while in addition to being unused, was also pushed down beyond the first set of operations on the stack pointer, negating the entire purpose. These days, we have an architecture independent arch_align_stack(), so we switch to using that instead. Move the initial alignment up before the initial stores while we're at it. Signed-off-by: Paul Mundt Signed-off-by: David Howells --- fs/binfmt_elf_fdpic.c | 25 ++++++++----------------- 1 files changed, 8 insertions(+), 17 deletions(-) diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index 7c83605..f9d6eaa 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -466,7 +466,8 @@ error_kill: #endif /* - * present useful information to the program + * present useful information to the program by shovelling it onto the new + * process's stack */ static int create_elf_fdpic_tables(struct linux_binprm *bprm, struct mm_struct *mm, @@ -482,9 +483,13 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm, int loop; int nr; /* reset for each csp adjustment */ - /* we're going to shovel a whole load of stuff onto the stack */ #ifdef CONFIG_MMU - sp = bprm->p; + /* In some cases (e.g. Hyper-Threading), we want to avoid L1 evictions + * by the processes running on the same package. One thing we can do is + * to shuffle the initial stack for them, so we give the architecture + * an opportunity to do so here. + */ + sp = arch_align_stack(bprm->p); #else sp = mm->start_stack; @@ -527,20 +532,6 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm, return -EFAULT; } -#if defined(__i386__) && defined(CONFIG_SMP) - /* in some cases (e.g. Hyper-Threading), we want to avoid L1 evictions - * by the processes running on the same package. One thing we can do is - * to shuffle the initial stack for them. - * - * the conditionals here are unneeded, but kept in to make the code - * behaviour the same as pre change unless we have hyperthreaded - * processors. This keeps Mr Marcelo Person happier but should be - * removed for 2.5 - */ - if (smp_num_siblings > 1) - sp = sp - ((current->pid % 64) << 7); -#endif - sp &= ~7UL; /* stack the load map(s) */