* make modules_prepare failing @ 2021-06-16 19:35 Tim Harvey 2021-06-16 19:55 ` Russell King (Oracle) 0 siblings, 1 reply; 4+ messages in thread From: Tim Harvey @ 2021-06-16 19:35 UTC (permalink / raw) To: Linux ARM Mailing List Greetings, I'm trying to understand how to use the 'modules_prepare' target to prepare kernel headers on a dev host appropriate for building out-of-tree modules on a target board. I'm interested in the minimum headers necessary and have noticed the Ubuntu 'linux-headers-*' packages are only about 24MiB. I've looked over https://www.kernel.org/doc/Documentation/kbuild/modules.txt and it does not provide an example showing how to build the headers in a different directory. $ make O=foo modules_prepare make[1]: Entering directory '/usr/src/venice/bsp/linux/foo' *** *** The source tree is not clean, please run 'make mrproper' *** in /usr/src/venice/bsp/linux *** /usr/src/venice/bsp/linux/Makefile:512: recipe for target 'outputmakefile' failed make[1]: *** [outputmakefile] Error 1 make[1]: Leaving directory '/usr/src/venice/bsp/linux/foo' Makefile:179: recipe for target 'sub-make' failed make: *** [sub-make] Error 2 A 'make mrproper' as suggested just complains that a .config is not found, but then if there is a .config found it will complain I need to make mrproper again. The 'modules_prepare' does work if I don't try to output to a different directory but then it isn't clear what to package compared to the entire >1GiB kernel source tree. I wish https://www.kernel.org/doc/Documentation/kbuild/modules.txt had an example expalining how a distro packager would create linux-headers-<foo>. I'm not familiar enough with Ubuntu packaging to understand how to disect how their packages are created. Any suggestions? Best regards, Tim _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: make modules_prepare failing 2021-06-16 19:35 make modules_prepare failing Tim Harvey @ 2021-06-16 19:55 ` Russell King (Oracle) 2021-06-16 20:21 ` Tim Harvey 0 siblings, 1 reply; 4+ messages in thread From: Russell King (Oracle) @ 2021-06-16 19:55 UTC (permalink / raw) To: Tim Harvey; +Cc: Linux ARM Mailing List On Wed, Jun 16, 2021 at 12:35:16PM -0700, Tim Harvey wrote: > Greetings, > > I'm trying to understand how to use the 'modules_prepare' target to > prepare kernel headers on a dev host appropriate for building > out-of-tree modules on a target board. I'm interested in the minimum > headers necessary and have noticed the Ubuntu 'linux-headers-*' > packages are only about 24MiB. > > I've looked over > https://www.kernel.org/doc/Documentation/kbuild/modules.txt and it > does not provide an example showing how to build the headers in a > different directory. > > $ make O=foo modules_prepare > make[1]: Entering directory '/usr/src/venice/bsp/linux/foo' > *** > *** The source tree is not clean, please run 'make mrproper' > *** in /usr/src/venice/bsp/linux > *** > /usr/src/venice/bsp/linux/Makefile:512: recipe for target > 'outputmakefile' failed > make[1]: *** [outputmakefile] Error 1 > make[1]: Leaving directory '/usr/src/venice/bsp/linux/foo' > Makefile:179: recipe for target 'sub-make' failed > make: *** [sub-make] Error 2 This means your tree (/usr/src/venice/bsp/linux) is not clean, it is not referring to "foo". It is only possible to do a split source/ object tree build with a clean source tree. So, this is telling you to do "make mrproper" with nothing else in the source directory - no O= argument. If that is still failing, then it suggests there is a file somewhere in the source tree that shouldn't be there. > The 'modules_prepare' does work if I don't try to output to a > different directory but then it isn't clear what to package compared > to the entire >1GiB kernel source tree. I'm not sure you're going about this in the correct way. Doing a split object tree build does not mean everything you need to build modules is in the object tree - much depends on the source tree for the kernel build infrastructure and the other header files in the include subdirectory, as well as other places (such as picking up architecture options from arch/*/Makefile and the architecture specific header files.) So, if you are thinking "I can just package up the object tree to build modules" that is not correct. > I wish https://www.kernel.org/doc/Documentation/kbuild/modules.txt had > an example expalining how a distro packager would create > linux-headers-<foo>. I'm not familiar enough with Ubuntu packaging to > understand how to disect how their packages are created. Isn't that package used for building the C library rather than for modules? That will likely be created by "make headers_install" which gives you all the headers for userspace to use with kernel internals sanitised away. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last! _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: make modules_prepare failing 2021-06-16 19:55 ` Russell King (Oracle) @ 2021-06-16 20:21 ` Tim Harvey 2021-06-16 20:37 ` Russell King (Oracle) 0 siblings, 1 reply; 4+ messages in thread From: Tim Harvey @ 2021-06-16 20:21 UTC (permalink / raw) To: Russell King (Oracle); +Cc: Linux ARM Mailing List On Wed, Jun 16, 2021 at 12:55 PM Russell King (Oracle) <linux@armlinux.org.uk> wrote: > > On Wed, Jun 16, 2021 at 12:35:16PM -0700, Tim Harvey wrote: > > Greetings, > > > > I'm trying to understand how to use the 'modules_prepare' target to > > prepare kernel headers on a dev host appropriate for building > > out-of-tree modules on a target board. I'm interested in the minimum > > headers necessary and have noticed the Ubuntu 'linux-headers-*' > > packages are only about 24MiB. > > > > I've looked over > > https://www.kernel.org/doc/Documentation/kbuild/modules.txt and it > > does not provide an example showing how to build the headers in a > > different directory. > > > > $ make O=foo modules_prepare > > make[1]: Entering directory '/usr/src/venice/bsp/linux/foo' > > *** > > *** The source tree is not clean, please run 'make mrproper' > > *** in /usr/src/venice/bsp/linux > > *** > > /usr/src/venice/bsp/linux/Makefile:512: recipe for target > > 'outputmakefile' failed > > make[1]: *** [outputmakefile] Error 1 > > make[1]: Leaving directory '/usr/src/venice/bsp/linux/foo' > > Makefile:179: recipe for target 'sub-make' failed > > make: *** [sub-make] Error 2 > > This means your tree (/usr/src/venice/bsp/linux) is not clean, it > is not referring to "foo". It is only possible to do a split source/ > object tree build with a clean source tree. > > So, this is telling you to do "make mrproper" with nothing else in > the source directory - no O= argument. If that is still failing, > then it suggests there is a file somewhere in the source tree that > shouldn't be there. > > > The 'modules_prepare' does work if I don't try to output to a > > different directory but then it isn't clear what to package compared > > to the entire >1GiB kernel source tree. > > I'm not sure you're going about this in the correct way. Doing a > split object tree build does not mean everything you need to build > modules is in the object tree - much depends on the source tree for > the kernel build infrastructure and the other header files in the > include subdirectory, as well as other places (such as picking up > architecture options from arch/*/Makefile and the architecture > specific header files.) > > So, if you are thinking "I can just package up the object tree to > build modules" that is not correct. > > > I wish https://www.kernel.org/doc/Documentation/kbuild/modules.txt had > > an example expalining how a distro packager would create > > linux-headers-<foo>. I'm not familiar enough with Ubuntu packaging to > > understand how to disect how their packages are created. > > Isn't that package used for building the C library rather than for > modules? That will likely be created by "make headers_install" which > gives you all the headers for userspace to use with kernel internals > sanitised away. Russell, Thanks for the response. I thought that Ubuntu's linux-headers-* package also provided enough to build out of tree modules but perhaps I'm wrong. Here is what I did to try and figure out what was in the linux-headers file on an Ubuntu bionic system: $ cat /etc/lsb-release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=18.04 DISTRIB_CODENAME=bionic DISTRIB_DESCRIPTION="Ubuntu 18.04.5 LTS" $ uname -r 5.4.0-73-generic $ dpkg -S /usr/src/linux-headers-5.4.0-73-generic linux-headers-5.4.0-73-generic: /usr/src/linux-headers-5.4.0-73-generic $ dpkg -L linux-headers-5.4.0-73-generic /. /lib /lib/modules /lib/modules/5.4.0-73-generic /usr /usr/share /usr/share/doc /usr/share/doc/linux-headers-5.4.0-73-generic /usr/share/doc/linux-headers-5.4.0-73-generic/changelog.Debian.gz /usr/share/doc/linux-headers-5.4.0-73-generic/copyright /usr/src /usr/src/linux-headers-5.4.0-73-generic /usr/src/linux-headers-5.4.0-73-generic/.config /usr/src/linux-headers-5.4.0-73-generic/.config.old /usr/src/linux-headers-5.4.0-73-generic/.gitignore /usr/src/linux-headers-5.4.0-73-generic/.missing-syscalls.d /usr/src/linux-headers-5.4.0-73-generic/Module.symvers /usr/src/linux-headers-5.4.0-73-generic/arch ... $ dpkg -L linux-headers-5.4.0-73-generic | grep -v "^/usr/src/linux-headers-5.4.0-73-generic" /. /lib /lib/modules /lib/modules/5.4.0-73-generic /usr /usr/share /usr/share/doc /usr/share/doc/linux-headers-5.4.0-73-generic /usr/share/doc/linux-headers-5.4.0-73-generic/changelog.Debian.gz /usr/share/doc/linux-headers-5.4.0-73-generic/copyright /usr/src /lib/modules/5.4.0-73-generic/build $ ls -l /lib/modules/5.4.0-73-generic/build lrwxrwxrwx 1 root root 39 Apr 16 07:44 /lib/modules/5.4.0-73-generic/build -> /usr/src/linux-headers-5.4.0-73-generic $ du -h /usr/src/linux-headers-5.4.0-73-generic/ | tail -n1 24M /usr/src/linux-headers-5.4.0-73-generic/ When I started poking around to see how I could create this I did find this guide here but it did not work (the whole mrproper clean issue): https://unix.stackexchange.com/questions/270123/how-to-create-usr-src-linux-headers-version-files What I am after is trying to see if I can easily appease users on embedded Linux boards that want to build out-of-tree modules on their target because they can't seem to wrap their head around building the kernel+modules on a development host with a cross-toolchain (the 'proper' way to do it but which has a huge barrier to entry for many users). They run into instructions online such as: # build out-of-tree module apt install build-essential apt install linux-headers-$(uname -r) # some out-of-tree modules have you point to kernel source via a non-std env var make KSRC=/lib/modules/$(uname -r)/build # others follow what the kernel docs have you do which is to do a make in the kernel dir make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules make install Best regards, Tim _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: make modules_prepare failing 2021-06-16 20:21 ` Tim Harvey @ 2021-06-16 20:37 ` Russell King (Oracle) 0 siblings, 0 replies; 4+ messages in thread From: Russell King (Oracle) @ 2021-06-16 20:37 UTC (permalink / raw) To: Tim Harvey; +Cc: Linux ARM Mailing List On Wed, Jun 16, 2021 at 01:21:36PM -0700, Tim Harvey wrote: > On Wed, Jun 16, 2021 at 12:55 PM Russell King (Oracle) > <linux@armlinux.org.uk> wrote: > > > > On Wed, Jun 16, 2021 at 12:35:16PM -0700, Tim Harvey wrote: > > > Greetings, > > > > > > I'm trying to understand how to use the 'modules_prepare' target to > > > prepare kernel headers on a dev host appropriate for building > > > out-of-tree modules on a target board. I'm interested in the minimum > > > headers necessary and have noticed the Ubuntu 'linux-headers-*' > > > packages are only about 24MiB. > > > > > > I've looked over > > > https://www.kernel.org/doc/Documentation/kbuild/modules.txt and it > > > does not provide an example showing how to build the headers in a > > > different directory. > > > > > > $ make O=foo modules_prepare > > > make[1]: Entering directory '/usr/src/venice/bsp/linux/foo' > > > *** > > > *** The source tree is not clean, please run 'make mrproper' > > > *** in /usr/src/venice/bsp/linux > > > *** > > > /usr/src/venice/bsp/linux/Makefile:512: recipe for target > > > 'outputmakefile' failed > > > make[1]: *** [outputmakefile] Error 1 > > > make[1]: Leaving directory '/usr/src/venice/bsp/linux/foo' > > > Makefile:179: recipe for target 'sub-make' failed > > > make: *** [sub-make] Error 2 > > > > This means your tree (/usr/src/venice/bsp/linux) is not clean, it > > is not referring to "foo". It is only possible to do a split source/ > > object tree build with a clean source tree. > > > > So, this is telling you to do "make mrproper" with nothing else in > > the source directory - no O= argument. If that is still failing, > > then it suggests there is a file somewhere in the source tree that > > shouldn't be there. > > > > > The 'modules_prepare' does work if I don't try to output to a > > > different directory but then it isn't clear what to package compared > > > to the entire >1GiB kernel source tree. > > > > I'm not sure you're going about this in the correct way. Doing a > > split object tree build does not mean everything you need to build > > modules is in the object tree - much depends on the source tree for > > the kernel build infrastructure and the other header files in the > > include subdirectory, as well as other places (such as picking up > > architecture options from arch/*/Makefile and the architecture > > specific header files.) > > > > So, if you are thinking "I can just package up the object tree to > > build modules" that is not correct. > > > > > I wish https://www.kernel.org/doc/Documentation/kbuild/modules.txt had > > > an example expalining how a distro packager would create > > > linux-headers-<foo>. I'm not familiar enough with Ubuntu packaging to > > > understand how to disect how their packages are created. > > > > Isn't that package used for building the C library rather than for > > modules? That will likely be created by "make headers_install" which > > gives you all the headers for userspace to use with kernel internals > > sanitised away. > > Russell, > > Thanks for the response. > > I thought that Ubuntu's linux-headers-* package also provided enough > to build out of tree modules but perhaps I'm wrong. Here is what I did > to try and figure out what was in the linux-headers file on an Ubuntu > bionic system: Maybe it does - I don't use it, so I don't really know. If you do want to see how ubuntu creates the package, you could grab the source for the package and look at how they build it - that's what I would do. Of course, such a source package would mean downloading the entire kernel source tarball. You'll also have to look at disabling other stuff that ubuntu builds (like the kernel binary packages themselves.) -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last! _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-06-16 20:39 UTC | newest] Thread overview: 4+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2021-06-16 19:35 make modules_prepare failing Tim Harvey 2021-06-16 19:55 ` Russell King (Oracle) 2021-06-16 20:21 ` Tim Harvey 2021-06-16 20:37 ` Russell King (Oracle)
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