From: Andrii Nakryiko <andriin@fb.com>
Date: Mon, 29 Jun 2020 17:47:58 -0700
Subject: tools/bpftool: Allow substituting custom vmlinux.h for the build
Patch-mainline: v5.9-rc1
Git-commit: ec23eb705620234421fd48fc2382490fcfbafc37
References: bsc#1177028
In some build contexts (e.g., Travis CI build for outdated kernel), vmlinux.h,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>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200630004759.521530-1-andriin@fb.com
Acked-by: Gary Lin <glin@suse.com>
---
tools/bpf/bpftool/Makefile | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -122,20 +122,24 @@ BPFTOOL_BOOTSTRAP := $(if $(OUTPUT),$(OU
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) \