unsubscribe backports On 8/24/16, Luis R. Rodriguez <mcgrof@xxxxxxxxxx> wrote: > On Wed, Aug 24, 2016 at 01:05:04PM +0200, Michal Marek wrote: >> On 2016-08-23 23:32, Luis R. Rodriguez wrote: >> > On Fri, Aug 19, 2016 at 11:07:36AM +0200, Michal Marek wrote: >> >> On 2016-08-18 19:55, Luis R. Rodriguez wrote: >> >>> On Wed, Aug 17, 2016 at 09:26:58PM +0200, Cristina Moraru wrote: >> >>> >> >>>> This patchset implements dynamic pegging of kconfig symbol >> >>>> into driver modinfo section >> >>> >> >>> First a little bit of motivation here helps, so let me try to >> >>> help fill in some gaps. This may help explain what you have >> >>> been working on a bit more. >> >>> >> >>> First, for those that were not Cc'd but curious about this work >> >>> so far, you can read the patches here: >> >>> >> >>> Original cover letter: >> >>> >> >>> https://lkml.kernel.org/r/1471462023-119645-1-git-send-email-cristina.moraru09@xxxxxxxxx >> >>> >> >>> https://marc.info/?l=linux-kernel&m=147146213519750&w=2 - patch 1 >> >>> https://marc.info/?l=linux-kernel&m=147146209019744&w=2 - patch 2 >> >>> https://marc.info/?l=linux-kernel&m=147146211819747&w=2 - patch 3 >> >>> https://marc.info/?l=linux-kernel&m=147146209119745&w=2 - patch 4 >> >>> https://marc.info/?l=linux-kernel&m=147146209519746&w=2 - patch 5 >> >>> >> >>> There are a few situations in which you may want to extract a >> >>> subset of Kconfig CONFIG_* symbols for a system. At least when >> >>> only considering modules: >> >>> >> >>> a) When optimizing build requirements for a kernel for a system. >> >>> That is you boot into a distro kernel and then want to build >> >>> a slim kernel only with sensible kernel configuration options. >> >>> >> >>> b) When you are on a distribution kernel but the distribution >> >>> kernel provided lacks hardware support for your device, you >> >>> may either want to upgrade the full kernel in which case you >> >>> want to do a) or -- you may want to just a backports release >> >>> which provides just the modules you need, you'd use it on top >> >>> of the distribution kernel. >> >> >> >> c) Having the mapping in sysfs would allow to simplify >> >> streamline_config.pl avoid parsing Makefiles in perl. >> > >> > Indeed, this was actually a side possible goal here :) only it seems >> > we totally forgot about it while addressing the work. >> > >> >> Only if the patch did not depend on streamline_config.pl :) >> > >> > Indeed, lets get rid of that dependency. >> > >> >> One idea would be to generate >> >> the Module.ksymb in a similar way we generate the modules.builtin >> >> file: >> >> Generate an alternate include/config/*.conf with all CONFIG_FOO=m >> >> replaced with >> >> >> >> CONFIG_FOO=m-CONFIG_FOO >> >> >> >> and in the Makefile, iterate over $(filter m-CONFIG_%, $(.VARIABLES)) >> >> to >> should be obj-m-CONFIG_% >> >> >> create the mapping. This would also properly cover cases where we >> >> build >> >> the $(obj-m) list from another list. It would certainly create other >> >> corner cases, but it's worth trying IMO. >> > >> > Neat, would that cover lib-m then as well or other targets that would >> > generate >> > modules ? >> >> This would have to be handled as well by the patch. Obviously it's not >> going to be as simple as described in a single paragraph of text :). > > Ah OK, it was not clear to me if your suggestion captured all modules > already. > There may still be a way. We just have to look harder. Then what precise > target was used would be irrelevant. > >> >> Another thing is that we do not necessarily need to record this >> >> information in .modinfo, but we can generate a list in >> >> /lib/modules/`uname -r`/ for consumption. It could also include >> >> drivers >> >> that are builtin in the current configuration. >> > >> > Well so one future use would be for instance a 'make udevconfig' which >> > in theory should be able then to scrape all possible related needed >> > device CONFIG_'s and then give you an optimal kernel configuration. >> > It'd be nice to be able to extract this from the kernel and modules >> > without needing build sources in /lib/modules/`uname -r`/. >> >> I meant that the file can be installed by modules_install. Like you have >> /lib/modules/`uname -r`/modules.builtin with recent kernels and recent >> distro packages. > > Got it. > >> But really, it's a minor issue how the information is >> presented to userspace. > > To us perhaps, but to userspace and users this is a big deal. It'd be nice > to be able to construct a kernel config only with what CONFIG's your > hardware > needs, doing this should mean trying to expose enough information in a way > userspace is easily able to handle. The reason to go with the mod section > stuff > was this was already being picked up by udevadm for its own hardware db > info, > so this seemed like a logical evolution, and it would not require your > kernel sources installed. > > Luis > -- > To unsubscribe from this list: send the line "unsubscribe backports" in > -- To unsubscribe from this list: send the line "unsubscribe backports" in
