From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with archive (Exim 4.43) id 1LiCqW-0000Pw-Un for mharc-grub-devel@gnu.org; Fri, 13 Mar 2009 15:15:04 -0400 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LiCqU-0000PS-WA for grub-devel@gnu.org; Fri, 13 Mar 2009 15:15:03 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LiCqQ-0000KX-ID for grub-devel@gnu.org; Fri, 13 Mar 2009 15:15:02 -0400 Received: from [199.232.76.173] (port=43812 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LiCqQ-0000KQ-AR for grub-devel@gnu.org; Fri, 13 Mar 2009 15:14:58 -0400 Received: from aybabtu.com ([69.60.117.155]:49825) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1LiCqP-0004qC-RT for grub-devel@gnu.org; Fri, 13 Mar 2009 15:14:58 -0400 Received: from [192.168.10.10] (helo=thorin) by aybabtu.com with esmtp (Exim 4.69) (envelope-from ) id 1LiChr-0008Gv-Qn for grub-devel@gnu.org; Fri, 13 Mar 2009 20:06:13 +0100 Received: from rmh by thorin with local (Exim 4.69) (envelope-from ) id 1LiCqA-0004U8-1f for grub-devel@gnu.org; Fri, 13 Mar 2009 20:14:42 +0100 Date: Fri, 13 Mar 2009 20:14:42 +0100 From: Robert Millan To: The development of GRUB 2 Message-ID: <20090313191442.GC17068@thorin> References: <49AB29BA.6040609@gmail.com> <20090311211541.GC29956@thorin> <49B82B65.3080506@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49B82B65.3080506@gmail.com> Organization: free as in freedom X-Message-Flag: Worried about Outlook viruses? Switch to Thunderbird! www.mozilla.com/thunderbird X-Debbugs-No-Ack: true User-Agent: Mutt/1.5.18 (2008-05-17) X-detected-operating-system: by monty-python.gnu.org: Genre and OS details not recognized. Subject: Re: ELF bugfixes X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: The development of GRUB 2 List-Id: The development of GRUB 2 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 13 Mar 2009 19:15:03 -0000 On Wed, Mar 11, 2009 at 10:21:41PM +0100, phcoder wrote: > Robert Millan wrote: >> On Mon, Mar 02, 2009 at 01:35:06AM +0100, phcoder wrote: >>> + * include/grub/elf.h: added missing attributes >> >> This should be a bit more descriptive. >> >>> for (i = 0; i < ehdr->e_phnum; i++) >>> if (phdr(i)->p_type == PT_LOAD && phdr(i)->p_filesz != 0) >>> { >>> - if (phdr(i)->p_paddr < phdr(lowest_segment)->p_paddr) >>> + if (lowest_segment == -1 + || phdr(i)->p_paddr < >>> phdr(lowest_segment)->p_paddr) >>> lowest_segment = i; >>> - if (phdr(i)->p_paddr > phdr(highest_segment)->p_paddr) >>> + if (highest_segment == -1 >>> + || phdr(i)->p_paddr > phdr(highest_segment)->p_paddr) >>> highest_segment = i; >>> } >> >> Why? > > Because if first segment doesn't have the PT_LOAD attribute set then it > should be considered in this comparison But you didn't remove the PT_LOAD check. And in the routine below that does the actual segment load, we still check for PT_LOAD. Those should be consistent, right? >>> - grub_multiboot_payload_entry_offset = ehdr->e_entry - phdr(lowest_segment)->p_vaddr; >>> + grub_multiboot_payload_entry_offset = ehdr->e_entry - phdr(lowest_segment)->p_paddr; >> >> Are you sure about this? IIRC e_entry is in the virtual address space. I >> think we had some trouble with this (with NetBSD?), which lead to the current >> use of p_vaddr in this line. >> > Actually now thinking I see that the problem is more deep. The section > which is loaded at the lowest address isn't necessarily the section > which contains entry point. I'll fix this part cleanly and will resubmit > the patch No, but AFAICT the entry point is defined relative to that address, regardless of which segment contains it. -- Robert Millan The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and how) you may access your data; but nobody's threatening your freedom: we still allow you to remove your data and not access it at all."