On 2022/7/9 6:42, Andrii Nakryiko wrote:
On Thu, Jul 7, 2022 at 6:37 AM Pu Lehui <pulehui@xxxxxxxxxx> 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 <pulehui@xxxxxxxxxx>
---
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
so brilliant，we can take it to other places where rely on bpftool.
thanks.
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
.
