On Wed, Nov 13, 2019 at 12:13 AM Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote: > > On 11/12/19 1:50 PM, Masahiro Yamada wrote: > > 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. > > Hmm, I am puzzled why that is. :/ I think there are two options, i) remove it > from CFLAGS like below (at least this doesn't let the build fail in my case > but requires linux headers to be installed) or ii) add a copy of filter.h to > tools/include/uapi/linux/filter.h so the few tools can just reuse it. We do have > bpf_common.h and bpf.h there already. > > diff --git a/tools/bpf/Makefile b/tools/bpf/Makefile > index 5d1995fd369c..08dfd289174c 100644 > --- a/tools/bpf/Makefile > +++ b/tools/bpf/Makefile > @@ -10,7 +10,6 @@ MAKE = make > INSTALL ?= install > > CFLAGS += -Wall -O2 > -CFLAGS += -D__EXPORTED_HEADERS__ -I$(srctree)/include/uapi -I$(srctree)/include > > # This will work when bpf is built in tools env. where srctree > # isn't set and when invoked from selftests build, where srctree > I think this is the most sane fix to include the linux/filter.h in the system. (probably, it is located in /usr/include/linux/filter.h) -- Best Regards Masahiro Yamada
