From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1IeWhn-00074B-Gc for qemu-devel@nongnu.org; Sun, 07 Oct 2007 10:02:03 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1IeWhl-00072G-S9 for qemu-devel@nongnu.org; Sun, 07 Oct 2007 10:02:03 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1IeWhl-000729-Pj for qemu-devel@nongnu.org; Sun, 07 Oct 2007 10:02:01 -0400 Received: from bangui.magic.fr ([195.154.194.245]) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1IeWhk-0008No-H3 for qemu-devel@nongnu.org; Sun, 07 Oct 2007 10:02:00 -0400 Subject: Re: [Qemu-devel] [RFC, PATCH] Support for loading 32 bit ELF files for 64 bit linux-user From: "J. Mayer" In-Reply-To: References: Content-Type: text/plain Date: Sun, 07 Oct 2007 16:01:56 +0200 Message-Id: <1191765716.9976.17.camel@rapid> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Blue Swirl On Sun, 2007-10-07 at 15:45 +0300, Blue Swirl wrote: > Hi, Hi, > This patch adds support for loading a 32 bit ELF file in the 64 bit > user mode emulator. This means that qemu-sparc64 can be used to > execute 32 bit ELF files containing V9 instructions (SPARC32PLUS). > This format is used by Solaris/Sparc and maybe by Debian in the > future. > > Other targets shouldn't be affected, but I have done only compile > testing. Any comments? The idea of loading 32 bits executables on 64 bits target seems great. Then, I got two remarks about this patch: - it seems that it does not take care about my patch. As I was to commit it today, I wonder if I still should do it. But then, your patch lacks some bugifxes (start_data not properly computed and TARGET_LONG_BITS != HOST_LONG_BITS problems). - it seems that quite all the ELF loader code is affected by your patch. I think (maybe too naively) that adding functions to read the ELF infos should be sufficient, ie add a read_elf_ehdr, ..., functions and a few patches in the create_elf_table function. Then, all informations nedded to load a 32 bits executable can be kept into the 64 bits structures. As the kernel does not duplicate the code to handle this case, I think Qemu loader should be kept as simple as the kernel one, and the elfload_ops.h seems to me to be useless. In fact, Qemu loader could (should ?) even be the same code than the kernel one with just a few helpers for endianness swaps and the needed fixes to avoid confusions between host_long and target_long... -- J. Mayer Never organized