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authorJean-Philippe Brucker <jean-philippe@linaro.org>2021-06-03 19:05:16 +0200
committerDaniel Borkmann <daniel@iogearbox.net>2021-06-08 21:59:08 +0200
commit0779890fed7817725f399d6ec85730e08ebfdeee (patch)
treea7323161645afc4cf70eaa8f85f58e96ce44b6a9 /tools/bpf
parentselftests/bpf: Add xdp_redirect_multi into .gitignore (diff)
downloadlinux-0779890fed7817725f399d6ec85730e08ebfdeee.tar.xz
linux-0779890fed7817725f399d6ec85730e08ebfdeee.zip
tools/bpftool: Fix cross-build
When the bootstrap and final bpftool have different architectures, we need to build two distinct disasm.o objects. Add a recipe for the bootstrap disasm.o. After commit d510296d331a ("bpftool: Use syscall/loader program in "prog load" and "gen skeleton" command.") cross-building bpftool didn't work anymore, because the bootstrap bpftool was linked using objects from different architectures: $ make O=/tmp/bpftool ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- -C tools/bpf/bpftool/ V=1 [...] aarch64-linux-gnu-gcc ... -c -MMD -o /tmp/bpftool/disasm.o /home/z/src/linux/kernel/bpf/disasm.c gcc ... -c -MMD -o /tmp/bpftool//bootstrap/main.o main.c gcc ... -o /tmp/bpftool//bootstrap/bpftool /tmp/bpftool//bootstrap/main.o ... /tmp/bpftool/disasm.o /usr/bin/ld: /tmp/bpftool/disasm.o: Relocations in generic ELF (EM: 183) /usr/bin/ld: /tmp/bpftool/disasm.o: Relocations in generic ELF (EM: 183) /usr/bin/ld: /tmp/bpftool/disasm.o: Relocations in generic ELF (EM: 183) /usr/bin/ld: /tmp/bpftool/disasm.o: error adding symbols: file in wrong format collect2: error: ld returned 1 exit status [...] The final bpftool was built for e.g. arm64, while the bootstrap bpftool, executed on the host, was built for x86. The problem here was that disasm.o linked into the bootstrap bpftool was arm64 rather than x86. With the fix we build two disasm.o, one for the target bpftool in arm64, and one for the bootstrap bpftool in x86. Fixes: d510296d331a ("bpftool: Use syscall/loader program in "prog load" and "gen skeleton" command.") Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210603170515.1854642-1-jean-philippe@linaro.org
Diffstat (limited to 'tools/bpf')
-rw-r--r--tools/bpf/bpftool/Makefile5
1 files changed, 4 insertions, 1 deletions
diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index d16d289ade7a..d73232be1e99 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -136,7 +136,7 @@ endif
BPFTOOL_BOOTSTRAP := $(BOOTSTRAP_OUTPUT)bpftool
-BOOTSTRAP_OBJS = $(addprefix $(BOOTSTRAP_OUTPUT),main.o common.o json_writer.o gen.o btf.o xlated_dumper.o btf_dumper.o) $(OUTPUT)disasm.o
+BOOTSTRAP_OBJS = $(addprefix $(BOOTSTRAP_OUTPUT),main.o common.o json_writer.o gen.o btf.o xlated_dumper.o btf_dumper.o disasm.o)
OBJS = $(patsubst %.c,$(OUTPUT)%.o,$(SRCS)) $(OUTPUT)disasm.o
VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux) \
@@ -180,6 +180,9 @@ endif
CFLAGS += $(if $(BUILD_BPF_SKELS),,-DBPFTOOL_WITHOUT_SKELETONS)
+$(BOOTSTRAP_OUTPUT)disasm.o: $(srctree)/kernel/bpf/disasm.c
+ $(QUIET_CC)$(HOSTCC) $(CFLAGS) -c -MMD -o $@ $<
+
$(OUTPUT)disasm.o: $(srctree)/kernel/bpf/disasm.c
$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD -o $@ $<