From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265590AbTFRWk5 (ORCPT ); Wed, 18 Jun 2003 18:40:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265592AbTFRWk4 (ORCPT ); Wed, 18 Jun 2003 18:40:56 -0400 Received: from aneto.able.es ([212.97.163.22]:11250 "EHLO aneto.able.es") by vger.kernel.org with ESMTP id S265590AbTFRWkk (ORCPT ); Wed, 18 Jun 2003 18:40:40 -0400 Date: Thu, 19 Jun 2003 00:54:36 +0200 From: "J.A. Magallon" To: Lista Linux-Kernel Cc: Marcelo Tosatti Subject: [RFC][PATCH] Correct AT_PLATFORM for HT P4 in 2.4.21 Message-ID: <20030618225436.GE3768@werewolf.able.es> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Disposition: inline Content-Transfer-Encoding: 7BIT X-Mailer: Balsa 2.0.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi all... Current kernel fails to set AT_PLATFORM when siblings are present, so HT-P4 fails to publish itself as an i686, and ld.so does not pick automatically i686 optmized libraries. Explanation of current bug in create_elf_tables::fs/binfmt_elf.c: u_platform is used both as the place where platform info is copied at the beginning of the process data area, and as the stack begin: - if (k_platform), it is copied at stack top, and u_platform is set to the beginning of that info. - if siblings are present, u_platform is moved to avoid cache conflicts and predictability - the address of u_platform is put to user space, but it has changed and now does not point to correct info This patch separates the two uses, stack and u_platform Note: it also changes the shifting factor from a fixed 64 to NR_CPUS to save some space... Comments ? --- linux/fs/binfmt_elf.c.orig 2002-12-28 00:12:32.000000000 +0100 +++ linux/fs/binfmt_elf.c 2002-12-28 00:32:37.000000000 +0100 @@ -116,11 +116,14 @@ elf_caddr_t *argv; elf_caddr_t *envp; elf_addr_t *sp, *csp; + char *stack_top; char *k_platform, *u_platform; long hwcap; size_t platform_len = 0; size_t len; + stack_top = p; + /* * Get hold of platform and hardware capabilities masks for * the machine we are running on. In some cases (Sparc), @@ -135,8 +138,8 @@ platform_len = strlen(k_platform) + 1; u_platform = p - platform_len; __copy_to_user(u_platform, k_platform, platform_len); - } else - u_platform = p; + stack_top = u_platform; + } #if defined(__i386__) && defined(CONFIG_SMP) /* @@ -149,15 +152,14 @@ * processors. This keeps Mr Marcelo Person happier but should be * removed for 2.5 */ - if(smp_num_siblings > 1) - u_platform = u_platform - ((current->pid % 64) << 7); + stack_top -= ((current->pid % NR_CPUS) << 7); #endif /* * Force 16 byte _final_ alignment here for generality. */ - sp = (elf_addr_t *)(~15UL & (unsigned long)(u_platform)); + sp = (elf_addr_t *)(~15UL & (unsigned long)(stack_top)); csp = sp; csp -= (1+DLINFO_ITEMS)*2 + (k_platform ? 2 : 0); #ifdef DLINFO_ARCH_ITEMS -- J.A. Magallon \ Software is like sex: werewolf.able.es \ It's better when it's free Mandrake Linux release 9.2 (Cooker) for i586 Linux 2.4.21-jam1 (gcc 3.3 (Mandrake Linux 9.2 3.3-1mdk))