From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Date: Tue, 2 Oct 2012 19:49:21 +0200 Subject: [Buildroot] Question about 64Bit kernel and 32Bit applications In-Reply-To: References: <20121002160254.3b94fe25@skate> Message-ID: <20121002194921.5fb92a46@skate> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Ronny, Please keep the list Cc'ed for Buildroot related discussions. On Tue, 2 Oct 2012 19:43:46 +0200, Ronny Meeus wrote: > The toolchain is available from cnusers.org. > You need to register first but once registered (can take 1 day or so), go to: > Downloads -> Downloads for registered users -> Octeon Software > development kit -> SDK 2.3 > This is the complete octeon SDK including an installed toochain, Linux > source code, example code, uboot etc for the Cavium reference boards. > This is the direct link: > http://www.cnusers.org/index.php?option=com_remository&Itemid=32&func=fileinfo&id=165 Ok, thanks, I'll have a look. However, if registration is required, integrating the toolchain in Buildroot will be difficult. > > And my opinion is that we should not try to support this. Unless I'm > > missing something, it is a really bizarre use case, and adding support > > for it would create an horrible additional complexity in Buildroot. > > In my opinion this usecase is not so bizarre. New applications can be > compiled in 64Bit mode while legacy applications (coming from a 32Bit > machine) can be compiled with the -mabi=n32 compiler option. If we > would not do this and just compile in 64Bit mode, the impact in the > application can be big (size of several types changes from 4 to 8 > bytes, impact on the size of data-types, alignment issues etc). > > What about the support to compile the userland with a different ABI > than the kernel? Sure. Do you know what changes we should do to make this possible? > > The change you did for libfuse cannot be integrated: it is MIPS > > specific, and we also have no way of specifying on a per-package basis > > whether it should be built for 32 bits or 64 bits. > > I just included this code to give you an indication of the changes I > needed to do ... Sure, that's the way I took your code, I just highlighted the reason why we couldn't accept this type of modification. Thanks! Thomas -- Thomas Petazzoni, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com