Apologies for delayed response - I've been horrendously busy. :-/ On Sun, Jul 08, 2018 at 11:03:12PM +0300, Adrian Bunk wrote: >On Wed, Jun 27, 2018 at 08:03:00PM +0000, Niels Thykier wrote: >>... >> armel/armhf: >> ------------ >> >> * Undesirable to keep the hardware running beyond 2020. armhf VM >> support uncertain. (DSA) >>... > >I'd like to get a clear picture regarding the situation of building >armel for buster on arm64, ideally moving it to arm64 hardwre soon.
ACK. >1. What issues are considered possible problems for moving building > armel from 32bit v7 hardware to 64bit v8 hardware? > >ARM has some history of adding new functionality in new versions of >their architecture that gets deprecated in the next version of their >architecture. > >The armel baseline (currently armv5te) is low enough that several >of the issues with running armhf code on arm64 are not present >when running armel code on arm64. > >If anyone sees potential blockers for building armel on arm64, >especially ones that are not present for building armhf on arm64, >please speak up now. I was worried about CP15 barriers, but I've been digging in docs for a while and can't find anything to back that up for v5. >2. What level of testing has been done before building armhf on arm64? > >64bit arm-arm-01 has started participating in building armhf for >unstable and experimental. > >I don't want to do less testing for armel than has been done for armhf >prior to doing that, what testing had been done for armhf on arm64 >building prior to doing it on a buildd? Not very much *so far*. I wsan't expecting to find any issues, but at least two clear issues have shown up so far: * Alignment fixups. We have these enabled on our v7 buildds, but there is no support for this at all in the arcm64 kernel. See #902990 as an example. * The definitions for MINSIGSTKSZ differ between armhf and arm64 - see #904385 To get an idea about these and any other problems, I've started a mass rebuild of the archive as armhf-on-arm64 on three machines at home. They're currently ~40% of the way through the archive and I estimate they are going to take another couple of weeks to complete. The next big problem I can see is in our haskell packages for armhf. From my build log for haskell-zxcvbn-c_1.0.1-4.log (as an example): ... Setting up llvm-3.9 (1:3.9.1-19+b1) ... Setting up ghc (8.2.2-4) ... Illegal instruction update-alternatives: using /usr/bin/ghc to provide /usr/bin/haskell-compiler (haskell-compiler) in auto mode Illegal instruction dpkg: error processing package ghc (--configure): installed ghc package post-installation script subprocess returned error exit status 132 ... I'm going to have a look at that later today. >3. Starting to build armel on arm64 > >Depending on the answers to the questions above I would like to >setup building armel on arm64, perhaps on the same arm-arm-01. Possibly. Let's see how things go - I'm looking at sourcing many more machines too... -- Steve McIntyre, Cambridge, UK. st...@einval.com "I can't ever sleep on planes ... call it irrational if you like, but I'm afraid I'll miss my stop" -- Vivek Das Mohapatra
