Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756624AbbLQQ0T (ORCPT ); Thu, 17 Dec 2015 11:26:19 -0500 Received: from mx2.suse.de ([195.135.220.15]:53358 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750936AbbLQQ0Q (ORCPT ); Thu, 17 Dec 2015 11:26:16 -0500 Date: Thu, 17 Dec 2015 17:26:13 +0100 From: Petr Mladek To: Jessica Yu Cc: Rusty Russell , Josh Poimboeuf , Seth Jennings , Jiri Kosina , Vojtech Pavlik , Jonathan Corbet , Miroslav Benes , linux-api@vger.kernel.org, live-patching@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [RFC PATCH v2 2/6] module: preserve Elf information for livepatch modules Message-ID: <20151217162613.GH3729@pathway.suse.cz> References: <1448943679-3412-1-git-send-email-jeyu@redhat.com> <1448943679-3412-3-git-send-email-jeyu@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1448943679-3412-3-git-send-email-jeyu@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1864 Lines: 50 On Mon 2015-11-30 23:21:15, Jessica Yu wrote: > For livepatch modules, copy Elf section, symbol, and string information > from the load_info struct in the module loader. > > Livepatch uses special relocation sections in order to be able to patch > modules that are not yet loaded, as well as apply patches to the kernel > when the addresses of symbols cannot be determined at compile time (for > example, when kaslr is enabled). Livepatch modules must preserve Elf > information such as section indices in order to apply the remaining > relocation sections at the appropriate time (i.e. when the target module > loads). > > Signed-off-by: Jessica Yu > --- > include/linux/module.h | 9 +++++ > kernel/module.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++-- > 2 files changed, 105 insertions(+), 2 deletions(-) > > diff --git a/include/linux/module.h b/include/linux/module.h > index 3a19c79..9b46256 100644 > --- a/include/linux/module.h > +++ b/include/linux/module.h > @@ -425,6 +425,14 @@ struct module { > > /* Notes attributes */ > struct module_notes_attrs *notes_attrs; > + > + /* Elf information (optionally saved) */ > + Elf_Ehdr *hdr; > + Elf_Shdr *sechdrs; > + char *secstrings; > + struct { > + unsigned int sym, str, mod, vers, info, pcpu; > + } index; > #endif I would hide this into a structure. It is 3 pointers and 6 integers that are mostly unused. I think about using a pointer to struct load_info here. We could set the unused stuff to zero and NULL. Any better idea how to share the definition with struct load_info is welcome. Best Regards, Petr -- 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/