[Xenomai] ipipe: kernel updates in the light of recent fixes (meltdown...)
Hi Philippe, as the number of question increase here, but I bet elsewhere as well, and I'm planning to work on some parts soonish, I'd like to coordinate: Where are we standing with 4.14 right now? There is nothing for x86 yet, right? What are the update plans for 4.9? We currently have one x86 user on that kernel, but I suppose we could also move on to 4.14 once it's ready. For me the question is right now where to invest x86-wise, 4.9 update or 4.14 completion + update? For 4.4, which we will need for product use for sure, I'm considering to lift the support from 4.4 LTS to the CIP [1][2] kernel. That one will be longer maintained and basically differs from LTS only in mainline backports of certain hardware support and critical features. Plus some reverts of broken LTS commits that will later on be reverted there as well. The fuss that meltdown brings in would be a good point to do the jump IMHO (there is no CIP kernel with meltdown fixes yet, due to issues in LTS, but that will change soon). Regarding spectre, I'm not expected that much impact on ipipe, but that situation is still too much in flux, even in upstream. What do you think? @all: What are requirements of other users here? Jan [1] https://git.kernel.org/pub/scm/linux/kernel/git/bwh/linux-cip.git [2] https://wiki.linuxfoundation.org/civilinfrastructureplatform/cipkernelmaintenance -- Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate Competence Center Embedded Linux ___ Xenomai mailing list Xenomai@xenomai.org https://xenomai.org/mailman/listinfo/xenomai
Re: [Xenomai] ipipe: kernel updates in the light of recent fixes (meltdown...)
I think using the CIP kernel would be a great idea. I can see this being popular with product developers. -Greg On Tue, Jan 23, 2018 at 12:52 PM, Jan Kiszka wrote: > Hi Philippe, > > as the number of question increase here, but I bet elsewhere as well, > and I'm planning to work on some parts soonish, I'd like to coordinate: > > Where are we standing with 4.14 right now? There is nothing for x86 yet, > right? > > What are the update plans for 4.9? We currently have one x86 user on > that kernel, but I suppose we could also move on to 4.14 once it's > ready. For me the question is right now where to invest x86-wise, 4.9 > update or 4.14 completion + update? > > For 4.4, which we will need for product use for sure, I'm considering to > lift the support from 4.4 LTS to the CIP [1][2] kernel. That one will be > longer maintained and basically differs from LTS only in mainline > backports of certain hardware support and critical features. Plus some > reverts of broken LTS commits that will later on be reverted there as > well. The fuss that meltdown brings in would be a good point to do the > jump IMHO (there is no CIP kernel with meltdown fixes yet, due to issues > in LTS, but that will change soon). > > Regarding spectre, I'm not expected that much impact on ipipe, but that > situation is still too much in flux, even in upstream. > > What do you think? > > @all: What are requirements of other users here? > > Jan > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/bwh/linux-cip.git > [2] > https://wiki.linuxfoundation.org/civilinfrastructureplatform/cipkernelmaintenance > > -- > Siemens AG, Corporate Technology, CT RDA IOT SES-DE > Corporate Competence Center Embedded Linux > > ___ > Xenomai mailing list > Xenomai@xenomai.org > https://xenomai.org/mailman/listinfo/xenomai ___ Xenomai mailing list Xenomai@xenomai.org https://xenomai.org/mailman/listinfo/xenomai
Re: [Xenomai] ipipe: kernel updates in the light of recent fixes (meltdown...)
Hi Jan, On 01/23/2018 06:52 PM, Jan Kiszka wrote: > Hi Philippe, > > as the number of question increase here, but I bet elsewhere as well, > and I'm planning to work on some parts soonish, I'd like to coordinate: > > Where are we standing with 4.14 right now? There is nothing for x86 yet, > right? > Correct. > What are the update plans for 4.9? We currently have one x86 user on > that kernel, but I suppose we could also move on to 4.14 once it's > ready. For me the question is right now where to invest x86-wise, 4.9 > update or 4.14 completion + update? > Regarding x86, 4.9 is still the current release for the pipeline. Porting to 4.14/x86 requires an overhaul of the fpu management in the pipeline and cobalt cores (actually, the mainline changes requiring this were introduced in the 4.11 timeframe). The basic issue is about dropping the assumptions cobalt does about the kernel using the lazy fpu scheme, since mainline switched to strict eager mode for x86, dropping the former option entirely. > For 4.4, which we will need for product use for sure, I'm considering to > lift the support from 4.4 LTS to the CIP [1][2] kernel. That one will be > longer maintained and basically differs from LTS only in mainline > backports of certain hardware support and critical features. Plus some > reverts of broken LTS commits that will later on be reverted there as > well. The fuss that meltdown brings in would be a good point to do the > jump IMHO (there is no CIP kernel with meltdown fixes yet, due to issues > in LTS, but that will change soon). > No objection. > Regarding spectre, I'm not expected that much impact on ipipe, but that > situation is still too much in flux, even in upstream. > > What do you think? > I did not have any issue porting dovetail (4th gen pipeline) to arm/4.15; although the pipeline implementation is quite different, the mm portions are similar, so there is hope for the current pipeline with respect to mainline changes to the generic vm core, the situation with x86-specific bits is likely going to be different for obvious reasons. I did not check in details though. > @all: What are requirements of other users here? > > Jan > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/bwh/linux-cip.git > [2] > https://wiki.linuxfoundation.org/civilinfrastructureplatform/cipkernelmaintenance > -- Philippe. ___ Xenomai mailing list Xenomai@xenomai.org https://xenomai.org/mailman/listinfo/xenomai
