Hi Randy, On 06/07/2018 05:07 PM, Randy Dunlap wrote: > On 06/06/2018 04:16 PM, Jayant Chowdhary wrote: >> In order for static analysis tools to analyze each of the uapi headers, >> we need to enable them to compile stand-alone. Some uapi headers were >> missing dependencies which would not make them compile stand-alone in >> user-land. This patch adds those dependencies. > > Hi, > > Thanks for getting started on this. I see that the kbuild robot and I were > still not able to do successful builds even after this patch is applied. > We were building different targets though. robot was doing kernel builds > and I was doing a large "all-uapi" build. > > I started on my all-uapi work about 1 week ago but haven't posted anything yet, > but it's posted (attached) below. It's not yet up to kernel quality yet (for a > Makefile), and I have made very little progress toward a successful userspace build. > > If anyone is interested, just put these 3 files in <kernel_tree>/tools/build > and then run: > > make ARCH=$some_arch O=build_dir headers_check > so that the headers will be cleaned up and installed in build_dir/usr/. > > Then run 'make -f all-uapi.mk' > and the userspace program with all header files found in build_dir/usr/include > will be built -- i.e., attempted (not successfully). > > (note: chmod +x hdr-fix-lines.pl) > > Thank you for this. This is surely a more formal way of finding out and verifying problems w.r.t the uapi headers, being compiled from user-land. I do have one concern with this approach though: the make target 'all-uapi.o' depends on all-uapi.h, which includes all the uapi headers installed in <build-dir>. So this does make sure that when all the uapi headers are included, a user-land program will be able to compile fine, without adding any additional dependencies. However, this could be masking some cases of dependency exclusion. An example can be seen as follows: Header dependency chain: A.h->B.h, however A.h doesn't actually include B.h C.h->B.h, C.h does include B.h all-uapi.h #include<C.h> #include<A.h> all-uapi.h will compile fine, since the inclusion of C.h before A.h satisfies A.h's dependency on B.h. However, if a user-land program includes just A.h, it will not compile without adding B.h. So the target being built successfully masked an issue with the uapi header, no? I guess it might be better to just have a Makefile which produces a target for each header in the set produced by 'make headers_install' and compile those, with a -I flag as <build-dir>/usr/include ? Also, do you think it might be better to do this work in phases ? I'm guessing we'll be seeing many headers to fix (especially arch specific ones). Fixing these separately: first the generic ones, followed by the ones for the arches, might be easier ? Thanks, Jayant -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
