On 12/07/2022 04:08, Pu Lehui wrote: > Currently, when cross compiling bpf samples, the host side cannot > use arch-specific bpftool to generate vmlinux.h or skeleton. Since > samples/bpf use bpftool for vmlinux.h, skeleton, and static linking > only, we can use lightweight bootstrap version of bpftool to handle > these, and it's always host-native. > > Signed-off-by: Pu Lehui <pulehui@xxxxxxxxxx> > Suggested-by: Andrii Nakryiko <andrii@xxxxxxxxxx> > --- > samples/bpf/Makefile | 16 +++++++++++----- > 1 file changed, 11 insertions(+), 5 deletions(-) > > diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile > index 5002a5b9a7da..57012b8259d2 100644 > --- a/samples/bpf/Makefile > +++ b/samples/bpf/Makefile > @@ -282,12 +282,18 @@ $(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 := $(BPFTOOL_OUTPUT)/bootstrap/bpftool > +ifeq ($(CROSS_COMPILE),) > $(BPFTOOL): $(LIBBPF) $(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)/ > + $(MAKE) -C $(BPFTOOLDIR) srctree=$(BPF_SAMPLES_PATH)/../../ \ > + OUTPUT=$(BPFTOOL_OUTPUT)/ \ > + LIBBPF_BOOTSTRAP_OUTPUT=$(LIBBPF_OUTPUT)/ \ > + LIBBPF_BOOTSTRAP_DESTDIR=$(LIBBPF_DESTDIR)/ bootstrap > +else > +$(BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) | $(BPFTOOL_OUTPUT) Thanks for this! Just trying to fully understand the details here. When cross-compiling, you leave aside the dependency on target-arch-libbpf, so that "make -C <bpftool-dir> bootstrap" rebuilds its own host-arch libbpf, is this correct? > + $(MAKE) -C $(BPFTOOLDIR) srctree=$(BPF_SAMPLES_PATH)/../../ \ > + OUTPUT=$(BPFTOOL_OUTPUT)/ bootstrap > +endif > > $(LIBBPF_OUTPUT) $(BPFTOOL_OUTPUT): > $(call msg,MKDIR,$@)
