On 11/12/19 8:31 PM, Will Deacon 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.
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?
Hi Will,
Thanks for your reply.
I tried to do "make asm-generic" operation before, but it just generated
asm/rwonce.h
in arch/*/include/generated directory and building tools/bpf still
cannot find it.
Perhaps, the Makefile of tools/bpf needs to be improved.
Best Regards,
Xiao Yang
Will
