On Tue, Nov 12, 2019 at 9:31 PM Will Deacon <will@xxxxxxxxxx> wrote: > > [+lkml, Masahiro, Alexei and Daniel] > > On Tue, Nov 12, 2019 at 04:56:39PM +0800, Xiao Yang wrote: > > With your patch[1], I alway get the following error when building > > tools/bpf: > > In case people want to reproduce this, my branch is here: > > https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/log/?h=lto > > > ---------------------------------------------------------------------------------- > > > > make -C tools/bpf/ > > make: Entering directory > > '/usr/src/perf_selftests-x86_64-rhel-7.6-642a312d47ceb54603630d9d04f5052f3b46d9a3/tools/bpf' > > > > Auto-detecting system features: > > ... libbfd: [ on ] > > ... disassembler-four-args: [ OFF ] > > > > CC bpf_jit_disasm.o > > CC bpf_dbg.o > > In file included from > > /usr/src/perf_selftests-x86_64-rhel-7.6-642a312d47ceb54603630d9d04f5052f3b46d9a3/include/uapi/linux/filter.h:9:0, > > from > > /usr/src/perf_selftests-x86_64-rhel-7.6-642a312d47ceb54603630d9d04f5052f3b46d9a3/tools/bpf/bpf_dbg.c:41: > > /usr/src/perf_selftests-x86_64-rhel-7.6-642a312d47ceb54603630d9d04f5052f3b46d9a3/include/linux/compiler.h:247:24: > > fatal error: asm/rwonce.h: No such file or directory > > #include <asm/rwonce.h> > > ^ > > compilation terminated. > > Makefile:61: recipe for target 'bpf_dbg.o' failed > > make: *** [bpf_dbg.o] Error 1 > > make: *** Waiting for unfinished jobs.... > > make: Leaving directory > > > > ---------------------------------------------------------------------------------- > > > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/commit/?h=lto&id=642a312d47ceb54603630d9d04f5052f3b46d9a3 > > > > It seems that include/linux/compiler.h cannot find the asm/rwonce.h because > > tools/bpf/Makefile doesn't include arch/*/include/generated/asm/rwonce.h. > > The problem with referring to the generated files is that they don't exist > unless you've configured the main source directory. The real problem here > seems to be that tools/bpf/ refers directly to header files in the kernel > sources without any understanding of kbuild, and therefore mandatory-y > headers simply don't exist when it goes looking for them. Please note tools/ is out of scope of Kbuild. The tools/ created a completely different build system. tools/bpf/ looks like a host program. Does it include a kernel-space header of the target architecture? I see a lots of header duplication in tools/include/, but I am not sure if tools/include/linux/filter.h is the correct header to include. > > Perhaps it's possible to introduce a dependency on a top-level "make > asm-generic" so that we can reference the generated headers from the arch > directly. Thoughts? > > Will -- Best Regards Masahiro Yamada
