arm May 2011

arm@lists.fedoraproject.org

35 participants
26 discussions

armv7hl requirements
by Jon Masters 13 May '11

13 May '11

Folks, I'd like to kick off a discussion about flags for ARMv7. My proposal here is that we treat v7hl as an entirely different architecture, and don't try any multi-arch kind of hacks (there isn't the established user base for Fedora ARM to justify doing any of those things at the moment). Things I think we should consider as a minimum: *). Little endian (obviously, but worth stating) (l) *). Cortex-A8 or higher fully compliant core(s) *). ARM VFP3 hardware floating point (h) *). ARM NEON Architecture *). Thumb2 interworking *). Your suggestion here? I think we should build for ARM (as opposed to Thumb2) but we should support interworking with Thumb2 code through the toolchain options. We should then later consider implementing some Thumb2 optimization. It's more armv7thl, but the (t) is implied since it's ARMv7 anyway. Several folks have begun looking at toolchain bringup based on the F-15 toolchain applied to an F-13 userspace initially. But I'd like us to discuss options/requirements for toolchains before we go too far. Once I get some feedback, I'll be updating the wiki, along with some more F-15 goals and (hopefully) generally useful stuff. Jon.

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aapcs-vfpv3 "hardfp" update
by Jon Masters 13 May '11

13 May '11

Folks, I met with various Linaro, ARM, Canonical, and Debian folks to discuss cross-distro compatibility as far as ABI. I will followup, including details of the Linaro forum we will use for discussion. Jon. -- Sent from my phone - message formatted and/or shortened accordingly.

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Fedora 2.6.38 kernel for ARM-OMAP
by d.marlin 12 May '11

12 May '11

I was looking to try a newer kernel on the beagle board and panda board I was using (both running F13), and decided to try building 2.6.38 from the Fedora 15 SRPM. I modified the spec file to include an option to build for armv7l, and added an armv7l config file, as well as armv7l support in Makefile.config. I also included one 2.6.39 upstream patch (PandaBoard-remove-unused-power-regulators). All the source and binary packages I built are in: http://people.redhat.com/dmarlin/packages/FedoraArm/ I built a kernel from the following source package: SRPMS/kernel-2.6.38.5-24.01.fc13.src.rpm using the F13 tools on the panda board, and installed and booted it on both the beagle and panda boards. The command I use to build it is: rpmbuild -bb --target=armv7l SPECS/kernel.spec Before installing the kernel binary RPM, I installed new linux-firmware and grubby RPMs on the boards. The 2.6.38 kernel requires a newer version of linux-firmware than is available in the F13 ARM repo, so I rebuilt the one from F15. The new grubby package is not really necessary, but I patched it to be armv7l aware, otherwise it defaults to x86 (and looks for lilo or grub bootloaders). The modifications also provide a placeholder in case I wanted to modify it further to create the uboot images for the beagle/panda boards. To install the kernel on the panda board I just use: rpm -ivh kernel-omap-2.6.38.5-24.01.fc13.armv7l.rpm It takes a while to install, since it has to install all the modules, make an initramfs, etc. I keep all the uboot files in /boot/uboot. To build the uboot images for this kernel I use: cd /boot mkimage -A arm -O linux -T kernel -C none -a 0x80008000 -e 0x80008000 -n 2.6.38.5-24.01.fc13.armv7l.omap -d vmlinuz-2.6.38.5-24.01.fc13.armv7l.omap uboot/uImage-2.6.38.5-24.01.fc13.armv7l.omap mkimage -A arm -O linux -T ramdisk -C none -a 0 -e 0 -n initramfs -d initramfs-2.6.38.5-24.01.fc13.armv7l.omap.img uboot/uInitrd-2.6.38.5-24.01.fc13.armv7l.omap I then reboot the board from the console, and interrupt the auto-boot script. The commands I use to boot and test the new kernel on the panda board are: setenv mpurate 800 setenv bootargs console=ttyO2,115200n8 mem=463M ro rootwait root=/dev/mmcblk0p4 mpurate=${mpurate} init=/sbin/init earlyprintk rd_NO_PLYMOUTH setenv bootcmd 'mmc rescan 0; mmc init; fatload mmc 0:1 0x80300000 uImage-2.6.38.5-24.01.fc13.armv7l.omap; fatload mmc 0:1 0x81600000 uInitrd-2.6.38.5-24.01.fc13.armv7l.omap; bootm 0x80300000 0x81600000' boot Your options may differ, depending on your flash configuration, uboot version, etc., but these work for me. I have not preformed extensive testing, but it does boot and seems to work well on the F13 rootfs. Notes: I have only modified this to build for armv7l. Further modifications will be necessary for other variants. The config file I used is based on an older existing ARM config, so I'm sure the options are not optimal. The config file does not follow the Fedora conventions (broken down between the generic, arch, and board config files). I'm not sure the best way to break this out and maintain it, so suggestions are welcome. Please let me know if you have any questions, comments, or suggestions. d.marlin

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Re: [fedora-arm] Linaro Developer Summit
by Jon Masters 08 May '11

08 May '11

Great. Already planned to be im those sessions :) Will come say hi tomorrow...catching up on work tonight. Staying at New York Palace (the overflow hotel down the street). Jon. -- Sent from my phone - message formatted and/or shortened accordingly. -----Original Message----- From: Michael Hope [michael.hope(a)linaro.org] Received: Saturday, 07 May 2011, 22:51 To: Jon Masters [jonathan(a)jonmasters.org] CC: Fedora ARM secondary architecture list [arm(a)lists.fedoraproject.org] Subject: Re: [fedora-arm] Linaro Developer Summit On Sun, May 8, 2011 at 8:26 AM, Jon Masters <jonathan(a)jonmasters.org> wrote: > Folks, > > I am attending the Linaro Developer Summit next week. If anyone else is > attending, please do say hi! Also, if there are topics you think are of > interest to the Fedora ARM project that I might or might not have > already thought about, let me know if I can do anything useful :) Hi Jon. I'm keen to meet up and talk about the ARMv7 hard float port. You might be interested in the toolchain sessions: http://summit.ubuntu.com/uds-o/track/linaro-toolchain/ and what we currently support: https://wiki.linaro.org/WorkingGroups/ToolChain/Flyer Come and say hello! I'm the guy at: https://wiki.linaro.org/MeetTheTeam#Toolchain -- Michael _______________________________________________ arm mailing list arm(a)lists.fedoraproject.org https://admin.fedoraproject.org/mailman/listinfo/arm

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Linaro Developer Summit
by Jon Masters 07 May '11

07 May '11

Folks, I am attending the Linaro Developer Summit next week. If anyone else is attending, please do say hi! Also, if there are topics you think are of interest to the Fedora ARM project that I might or might not have already thought about, let me know if I can do anything useful :) I'll send a followup with some notes from the event. Jon.

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armv7hl VFP notes
by Jon Masters 04 May '11

04 May '11

Folks, This might be of use to someone else trying to figure this out. I am going to followup with a thread proposing some flags to consider for building toolchains based around a minimum of VFP3 *AND* NEON (with some emphasis on discussion about the latter), and Thumb2 interworking. But for now, you might find this useful if you're trying to figure out which way is up when it comes to some of the ARM ABI nomenclature. ARM has had several ABIs over the years. Linux blazed a trail (OABI) prior to the real ARM-backed standardization that is known as the official "Application Binary Interface (ABI) for the ARM Architecture". This is frequently referred to as EABI, though that is not its name and there is only a minor reference to that in the docs. You really want to look at the ABI documentation, of which there are many different levels: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ihi0044d/index.… There is an overview PDF document there, and also the specifics for ELF, DWARF, and for the Procedure Call Standard for ARM Architecture (AAPCS). To start reading, visit "ABI for the ARM Architecture (Base Standard)": http://infocenter.arm.com/help/topic/com.arm.doc.ihi0036b/IHI0036B_bsabi.pdf However. The real dirt you're looking for is documented in the AAPCS (which replaced the APCS/even earlier stuff), which you can find here: http://infocenter.arm.com/help/topic/com.arm.doc.ihi0042d/IHI0042D_aapcs.pdf Specifically, section 6 alludes to "The Standard Variants" and talks about modifications for improved performance on VFP. Basically, a sub-variant of the AAPCS that is ABI incompatible with the base. This seems to be referred to around the interwebs as aapcs-vfp, for example by some of the gcc folks, though the official document on ARM's website cunningly manages to avoid having any useful references to that name, or to specifically calling out this as the official "hard float ABI". Anyway, it seems when we're talking about "The hardfp ABI", what we really mean is aapcs-vfp. Unless I'm smoking something, can we all please use the real names for things so we give others a hope of figuring this stuff out without trawling through piles of docs :) I can't speak for other projects, but I'd like it if we did! Then I'd like it if the official docs would be fixed to make this more clear too! Jon.

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arm May 2011