On Thu, Jul 7, 2022 at 6:37 AM Pu Lehui <[email protected]> wrote:
>
> Currently, when cross compiling bpf samples, the host side
> cannot use arch-specific bpftool to generate vmlinux.h or
> skeleton. We need to compile the bpftool with the host
> compiler.
>
> Signed-off-by: Pu Lehui <[email protected]>
> ---
samples/bpf use bpftool for vmlinux.h, skeleton, and static linking
only. All that is supported by lightweight "bootstrap" bpftool
version, so we can build just that. It will be faster, and bootstrap
version should be always host-native even during cross compilation.
See [0] for what I did in libbpf-bootstrap.
Also please cc Quention for bpftool-related changes. Thanks!
[0] https://github.com/libbpf/libbpf-bootstrap/commit/fc28424eb3f0e39cfb5959296b070389b9a8bd8f
> samples/bpf/Makefile | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
> index 5002a5b9a7da..fe54a8c8f312 100644
> --- a/samples/bpf/Makefile
> +++ b/samples/bpf/Makefile
> @@ -1,4 +1,5 @@
> # SPDX-License-Identifier: GPL-2.0
> +-include tools/scripts/Makefile.include
>
> BPF_SAMPLES_PATH ?= $(abspath $(srctree)/$(src))
> TOOLS_PATH := $(BPF_SAMPLES_PATH)/../../tools
> @@ -283,11 +284,10 @@ $(LIBBPF): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OU
> BPFTOOLDIR := $(TOOLS_PATH)/bpf/bpftool
> BPFTOOL_OUTPUT := $(abspath $(BPF_SAMPLES_PATH))/bpftool
> BPFTOOL := $(BPFTOOL_OUTPUT)/bpftool
> -$(BPFTOOL): $(LIBBPF) $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) | $(BPFTOOL_OUTPUT)
> +$(BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) | $(BPFTOOL_OUTPUT)
> $(MAKE) -C $(BPFTOOLDIR) srctree=$(BPF_SAMPLES_PATH)/../../ \
> - OUTPUT=$(BPFTOOL_OUTPUT)/ \
> - LIBBPF_OUTPUT=$(LIBBPF_OUTPUT)/ \
> - LIBBPF_DESTDIR=$(LIBBPF_DESTDIR)/
> + ARCH= CROSS_COMPILE= CC=$(HOSTCC) LD=$(HOSTLD) \
> + OUTPUT=$(BPFTOOL_OUTPUT)/
>
> $(LIBBPF_OUTPUT) $(BPFTOOL_OUTPUT):
> $(call msg,MKDIR,$@)
> --
> 2.25.1
>