The -target option has been deprecated since clang 3.4 in 2013. Therefore, use
the preferred --target=bpf form instead. This also matches how we use --target=
in scripts/Makefile.clang.

Signed-off-by: Fangrui Song <maskray@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Link: https://github.com/llvm/llvm-project/commit/274b6f0c87a6a1798de0a68135afc7f95def6277
Link: https://lore.kernel.org/bpf/20230624001856.1903733-1-maskray@google.com

This makes it possible to add sanitizer flags.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230210001210.395194-3-iii@linux.ibm.com

tools/runqslower use bpftool for vmlinux.h, skeleton, and static linking
only. So we can use lightweight bootstrap version of bpftool to handle
these, and it will be faster.

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220714024612.944071-3-pulehui@huawei.com

Explicitly set libbpf 1.0 API mode, then we can avoid using the deprecated
RLIMIT_MEMLOCK.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220409125958.92629-5-laoar.shao@gmail.com

On ppc64le, trying to build bpf seltests throws the below warning:
  In file included from runqslower.bpf.c:5:
  ./runqslower.h:7:8: error: redefinition of 'event'
  struct event {
	 ^
  /home/naveen/linux/tools/testing/selftests/bpf/tools/build/runqslower/vmlinux.h:156602:8:
  note: previous definition is here
  struct event {
	 ^

This happens since 'struct event' is defined in
drivers/net/ethernet/alteon/acenic.h . Rename the one in runqslower to a
more appropriate 'runq_event' to avoid the naming conflict.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c13cb3767d26257ca4387b8296b632b433a58db6.1641468127.git.naveen.n.rao@linux.vnet.ibm.com

Cross-building using clang requires passing the "-target" flag rather
than using the CROSS_COMPILE prefix. Makefile.include transforms
CROSS_COMPILE into CLANG_CROSS_FLAGS. Add them to CFLAGS, and erase
CROSS_COMPILE for the bpftool build, since it needs to be executed on
the host.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20211216163842.829836-6-jean-philippe@linaro.org

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Commit be79505caf3f ("tools/runqslower: Install libbpf headers when
building") uses the target libbpf to build the host bpftool, which
doesn't work when cross-building:

  make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- -C tools/bpf/runqslower O=/tmp/runqslower
  ...
    LINK    /tmp/runqslower/bpftool/bpftool
  /usr/bin/ld: /tmp/runqslower/libbpf/libbpf.a(libbpf-in.o): Relocations in generic ELF (EM: 183)
  /usr/bin/ld: /tmp/runqslower/libbpf/libbpf.a: error adding symbols: file in wrong format
  collect2: error: ld returned 1 exit status

When cross-building, the target architecture differs from the host. The
bpftool used for building runqslower is executed on the host, and thus
must use a different libbpf than that used for runqslower itself.
Remove the LIBBPF_OUTPUT and LIBBPF_DESTDIR parameters, so the bpftool
build makes its own library if necessary.

In the selftests, pass the host bpftool, already a prerequisite for the
runqslower recipe, as BPFTOOL_OUTPUT. The runqslower Makefile will use
the bpftool that's already built for selftests instead of making a new
one.

Fixes: be79505caf3f ("tools/runqslower: Install libbpf headers when building")
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20211112155128.565680-1-jean-philippe@linaro.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Use v1.0+ compatible variant of perf_buffer__new() call to prepare for
deprecation.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211111053624.190580-9-andrii@kernel.org

API headers from libbpf should not be accessed directly from the
library's source directory. Instead, they should be exported with "make
install_headers". Let's make sure that runqslower installs the
headers properly when building.

We use a libbpf_hdrs target to mark the logical dependency on libbpf's
headers export for a number of object files, even though the headers
should have been exported at this time (since bpftool needs them, and is
required to generate the skeleton or the vmlinux.h).

When descending from a parent Makefile, the specific output directories
for building the library and exporting the headers are configurable with
BPFOBJ_OUTPUT and BPF_DESTDIR, respectively. This is in addition to
OUTPUT, on top of which those variables are constructed by default.

Also adjust the Makefile for the BPF selftests. We pass a number of
variables to the "make" invocation, because we want to point runqslower
to the (target) libbpf shared with other tools, instead of building its
own version. In addition, runqslower relies on (target) bpftool, and we
also want to pass the proper variables to its Makefile so that bpftool
itself reuses the same libbpf.

Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211007194438.34443-6-quentin@isovalent.com