From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753280AbcGSHUh (ORCPT ); Tue, 19 Jul 2016 03:20:37 -0400 Received: from icp-osb-irony-out6.external.iinet.net.au ([203.59.1.106]:34786 "EHLO icp-osb-irony-out6.external.iinet.net.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752933AbcGSHUf (ORCPT ); Tue, 19 Jul 2016 03:20:35 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: A2AtBQDD041X/zXSMGcNThsBAQGDdypSo3QGkl6ECRqGAAKBfAEBAQEBAYVpAQEBAQIBeQULCw0LLlcGAQwGAgEBiCSuaY58AQEBAQEBAQMBAQEBAQEhhWKCQAiCTYEiiHkFiB+RBAGGE4o3hFmDI4VQkB6DEoFHXIgQAQEB X-IPAS-Result: A2AtBQDD041X/zXSMGcNThsBAQGDdypSo3QGkl6ECRqGAAKBfAEBAQEBAYVpAQEBAQIBeQULCw0LLlcGAQwGAgEBiCSuaY58AQEBAQEBAQMBAQEBAQEhhWKCQAiCTYEiiHkFiB+RBAGGE4o3hFmDI4VQkB6DEoFHXIgQAQEB X-IronPort-AV: E=Sophos;i="5.28,388,1464624000"; d="scan'208";a="254200670" Subject: Re: [PULL REQUEST] [PATCH v2 00/10] allow BFLT executables on systems with a MMU To: Nicolas Pitre , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org References: <1468812716-30537-1-git-send-email-nicolas.pitre@linaro.org> Cc: Alexander Viro , David Howells From: Greg Ungerer Message-ID: <6b75e7a0-e181-08da-5013-315f6c45f02a@linux-m68k.org> Date: Tue, 19 Jul 2016 17:21:30 +1000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <1468812716-30537-1-git-send-email-nicolas.pitre@linaro.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Nicolas, On 18/07/16 13:31, Nicolas Pitre wrote: > This series provides the necessary changes to allow "flat" executable > binaries meant for no-MMU systems to actually run on systems with a MMU. > > This can also be found in the following git repo: > > git://git.linaro.org/people/nicolas.pitre/linux binfmt_flat_with_mmu > > *Why?* > > Because developing and testing natively on a large system with lots of > RAM makes it so much more convenient to use all the existing profiling > tools and debugging facilities that a kernel with lots of RAM can give. > And incidentally, those systems with lots of RAM all have a MMU. > > *Why not use elf_fdpic?* > > The flat executable format is simple with very small footprint > overhead, either in the executables themselves or kernel support. > This makes the flat format more suitable than elf_fdpic for very small > single-user-app embedded systems. > > And while elf_fdpic binaries can run on MMU systems, flat binaries still > couldn't, which just felt wrong. > > So here it is. The no-MMU support should remain unaffected. Please consider > for pulling. > > Tested on ARM only with a busybox build. Tested on m68k (ColdFire specifically) and everything compiles cleanly and works as before. I tried running a flat binary on an MMU ColdFire system and that crashed out with a SIGSEGV. I haven't debugged any further than that yet. I had a look over the patches and I didn't see any specific problems. So from me: Reviewed-by: Greg Ungerer When I get a minute I'll dig a little into that bflat running on MMU problem on ColdFire. Regards Greg > Changes since v1: > > - Removed SuperH and Xtensa from the Kconfig rule as they fail to build > due to lack of get/put_unaligned_user(). > > - Clarified some commit logs a bit. > > diffstat: > > arch/arm/include/asm/flat.h | 5 +- > arch/m68k/include/asm/flat.h | 5 +- > fs/Kconfig.binfmt | 3 +- > fs/binfmt_elf_fdpic.c | 38 +--- > fs/binfmt_flat.c | 372 +++++++++++++++++++++-------------- > fs/exec.c | 33 ++++ > include/linux/binfmts.h | 2 + > 7 files changed, 268 insertions(+), 190 deletions(-) > >