| Message ID | 20200630004759.521530-1-andriin@fb.com |
|---|---|
| State | Accepted |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | [bpf-next,1/2] tools/bpftool: allow substituting custom vmlinux.h for the build | expand |
On 6/29/20 5:47 PM, Andrii Nakryiko wrote: > In some build contexts (e.g., Travis CI build for outdated kernel), vmlinux.h, > generated from available kernel, doesn't contain all the types necessary for > BPF program compilation. For such set up, the most maintainable way to deal > with this problem is to keep pre-generated (almost up-to-date) vmlinux.h > checked in and use it for compilation purposes. bpftool after that can deal > with kernel missing some of the features in runtime with no problems. > > To that effect, allow to specify path to custom vmlinux.h to bpftool's > Makefile with VMLINUX_H variable. > > Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Yonghong Song <yhs@fb.com>
On 6/30/20 2:47 AM, Andrii Nakryiko wrote: > In some build contexts (e.g., Travis CI build for outdated kernel), vmlinux.h, > generated from available kernel, doesn't contain all the types necessary for > BPF program compilation. For such set up, the most maintainable way to deal > with this problem is to keep pre-generated (almost up-to-date) vmlinux.h > checked in and use it for compilation purposes. bpftool after that can deal > with kernel missing some of the features in runtime with no problems. > > To that effect, allow to specify path to custom vmlinux.h to bpftool's > Makefile with VMLINUX_H variable. > > Signed-off-by: Andrii Nakryiko <andriin@fb.com> Both applied, thanks!
diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile index 8c6563e56ffc..273da1615503 100644 --- a/tools/bpf/bpftool/Makefile +++ b/tools/bpf/bpftool/Makefile @@ -122,20 +122,24 @@ BPFTOOL_BOOTSTRAP := $(if $(OUTPUT),$(OUTPUT)bpftool-bootstrap,./bpftool-bootstr BOOTSTRAP_OBJS = $(addprefix $(OUTPUT),main.o common.o json_writer.o gen.o btf.o) OBJS = $(patsubst %.c,$(OUTPUT)%.o,$(SRCS)) $(OUTPUT)disasm.o -VMLINUX_BTF_PATHS := $(if $(O),$(O)/vmlinux) \ +VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux) \ $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux) \ ../../../vmlinux \ /sys/kernel/btf/vmlinux \ /boot/vmlinux-$(shell uname -r) -VMLINUX_BTF := $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS)))) +VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS)))) -ifneq ($(VMLINUX_BTF),) +ifneq ($(VMLINUX_BTF)$(VMLINUX_H),) ifeq ($(feature-clang-bpf-co-re),1) BUILD_BPF_SKELS := 1 $(OUTPUT)vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL_BOOTSTRAP) +ifeq ($(VMLINUX_H),) $(QUIET_GEN)$(BPFTOOL_BOOTSTRAP) btf dump file $< format c > $@ +else + $(Q)cp "$(VMLINUX_H)" $@ +endif $(OUTPUT)%.bpf.o: skeleton/%.bpf.c $(OUTPUT)vmlinux.h $(LIBBPF) $(QUIET_CLANG)$(CLANG) \
In some build contexts (e.g., Travis CI build for outdated kernel), vmlinux.h, generated from available kernel, doesn't contain all the types necessary for BPF program compilation. For such set up, the most maintainable way to deal with this problem is to keep pre-generated (almost up-to-date) vmlinux.h checked in and use it for compilation purposes. bpftool after that can deal with kernel missing some of the features in runtime with no problems. To that effect, allow to specify path to custom vmlinux.h to bpftool's Makefile with VMLINUX_H variable. Signed-off-by: Andrii Nakryiko <andriin@fb.com> --- tools/bpf/bpftool/Makefile | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)