Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758033AbZGCUQk (ORCPT ); Fri, 3 Jul 2009 16:16:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755825AbZGCUQb (ORCPT ); Fri, 3 Jul 2009 16:16:31 -0400 Received: from cantor.suse.de ([195.135.220.2]:53979 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755150AbZGCUQa (ORCPT ); Fri, 3 Jul 2009 16:16:30 -0400 Message-ID: <4A4E671C.2090201@suse.cz> Date: Fri, 03 Jul 2009 22:16:28 +0200 From: Michal Marek User-Agent: Thunderbird 2.0.0.19 (X11/20081227) MIME-Version: 1.0 To: Jan Beulich Cc: Ingo Molnar , tony.luck@intel.com, Thomas Gleixner , Rusty Russell , hpa@zytor.com, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-modules@vger.kernel.org Subject: Re: [PATCH] reduce export symbol CRC table size on 64-bit archs References: <4A4A18780200007800008345@vpn.id2.novell.com> In-Reply-To: <4A4A18780200007800008345@vpn.id2.novell.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2123 Lines: 61 Jan Beulich napsal(a): > Since these CRCs are really only 32-bit quantities, there's no need to > store them in 64-bit slots. Since, however, gcc doesn't allow > respective initializations, asm() constructs get used to create the CRC > tables (and its for that reason that the patch only makes x86-64 and > ia64 utilize that functionality, as I can't verify this doesn't break > in some subtle way elsewhere). > ... > struct modversion_info > { > - unsigned long crc; > + ksym_crc_t crc; > char name[MODULE_NAME_LEN]; > }; This change breaks module-init-tools: Before: $ /sbin/modprobe --dump-modversions _build/drivers/usb/core/usbcore.ko | head 0xb49b735a module_layout 0xdb7e6a70 bus_register 0xe3a25bcc device_remove_file 0x1fedf0f4 __request_region 0x37429b3b device_remove_bin_file 0x27ac237c cdev_del 0xf3be63b3 per_cpu__current_task 0x26b76a45 kmalloc_caches 0x5a34a45c __kmalloc 0x1c820358 cdev_init After: $ /sbin/modprobe --dump-modversions _build-crc-int/drivers/usb/core/usbcore.ko | head 0x75646f6d91ea7b5c le_layout 0x5f7375623e215f43 register 0x69766564848c67e2 ce_remove_file 0x65725f5f1fedf0f4 quest_region 0x69766564a0c29c25 ce_remove_bin_file 0x766564633ce98bc2 _del 0x5f72657012c9615b cpu__current_task 0x6c616d6b6ea6c464 loc_caches 0x6d6b5f5f5a34a45c alloc 0x766564631e5d885b _init It also breaks the newly added depmod -E option (check symbol versions), which also reads the struct modversion_info array (*). Is it possible name the section differently (__versions2?) on those architectures where the size changes, so that it is possible to fix m-i-t in a backwards-compatible manner? Michal (*) dump_modvers() and load_symbols() in http://git.kernel.org/?p=utils/kernel/module-init-tools/module-init-tools.git;a=blob;f=elfops_core.c;hb=HEAD -- 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/