I got the following error when I tried to build perf on a read-only
filesystem with O=dir option.
$ cd /some/where/ro/linux/tools/perf
$ make O=$HOME/build/perf
...
CC /home/namhyung/build/perf/lib.o
/bin/sh: bpf_helper_defs.h: Read-only file system
make[3]: *** [Makefile:184: bpf_helper_defs.h] Error 1
make[2]: *** [Makefile.perf:778: /home/namhyung/build/perf/libbpf.a] Error 2
make[2]: *** Waiting for unfinished jobs....
LD /home/namhyung/build/perf/libperf-in.o
AR /home/namhyung/build/perf/libperf.a
PERF_VERSION = 5.4.0
make[1]: *** [Makefile.perf:225: sub-make] Error 2
make: *** [Makefile:70: all] Error 2
It was becaused bpf_helper_defs.h was generated in current directory.
Move it to OUTPUT directory.
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/lib/bpf/Makefile | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index 99425d0be6ff..2f42a35f4634 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -159,7 +159,7 @@ all: fixdep
all_cmd: $(CMD_TARGETS) check
-$(BPF_IN_SHARED): force elfdep bpfdep bpf_helper_defs.h
+$(BPF_IN_SHARED): force elfdep bpfdep $(OUTPUT)bpf_helper_defs.h
@(test -f ../../include/uapi/linux/bpf.h -a -f ../../../include/uapi/linux/bpf.h && ( \
(diff -B ../../include/uapi/linux/bpf.h ../../../include/uapi/linux/bpf.h >/dev/null) || \
echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf.h' differs from latest version at 'include/uapi/linux/bpf.h'" >&2 )) || true
@@ -177,12 +177,12 @@ $(BPF_IN_SHARED): force elfdep bpfdep bpf_helper_defs.h
echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/if_xdp.h' differs from latest version at 'include/uapi/linux/if_xdp.h'" >&2 )) || true
$(Q)$(MAKE) $(build)=libbpf OUTPUT=$(SHARED_OBJDIR) CFLAGS="$(CFLAGS) $(SHLIB_FLAGS)"
-$(BPF_IN_STATIC): force elfdep bpfdep bpf_helper_defs.h
+$(BPF_IN_STATIC): force elfdep bpfdep $(OUTPUT)bpf_helper_defs.h
$(Q)$(MAKE) $(build)=libbpf OUTPUT=$(STATIC_OBJDIR)
-bpf_helper_defs.h: $(srctree)/include/uapi/linux/bpf.h
+$(OUTPUT)bpf_helper_defs.h: $(srctree)/include/uapi/linux/bpf.h
$(Q)$(srctree)/scripts/bpf_helpers_doc.py --header \
- --file $(srctree)/include/uapi/linux/bpf.h > bpf_helper_defs.h
+ --file $(srctree)/include/uapi/linux/bpf.h > $(OUTPUT)bpf_helper_defs.h
$(OUTPUT)libbpf.so: $(OUTPUT)libbpf.so.$(LIBBPF_VERSION)
@@ -246,7 +246,7 @@ install_lib: all_cmd
$(call do_install_mkdir,$(libdir_SQ)); \
cp -fpR $(LIB_FILE) $(DESTDIR)$(libdir_SQ)
-install_headers: bpf_helper_defs.h
+install_headers: $(OUTPUT)bpf_helper_defs.h
$(call QUIET_INSTALL, headers) \
$(call do_install,bpf.h,$(prefix)/include/bpf,644); \
$(call do_install,libbpf.h,$(prefix)/include/bpf,644); \
@@ -254,7 +254,7 @@ install_headers: bpf_helper_defs.h
$(call do_install,libbpf_util.h,$(prefix)/include/bpf,644); \
$(call do_install,xsk.h,$(prefix)/include/bpf,644); \
$(call do_install,bpf_helpers.h,$(prefix)/include/bpf,644); \
- $(call do_install,bpf_helper_defs.h,$(prefix)/include/bpf,644); \
+ $(call do_install,$(OUTPUT)bpf_helper_defs.h,$(prefix)/include/bpf,644); \
$(call do_install,bpf_tracing.h,$(prefix)/include/bpf,644); \
$(call do_install,bpf_endian.h,$(prefix)/include/bpf,644); \
$(call do_install,bpf_core_read.h,$(prefix)/include/bpf,644);
@@ -274,7 +274,7 @@ install: install_lib install_pkgconfig
clean:
$(call QUIET_CLEAN, libbpf) $(RM) -rf $(CMD_TARGETS) \
*.o *~ *.a *.so *.so.$(LIBBPF_MAJOR_VERSION) .*.d .*.cmd \
- *.pc LIBBPF-CFLAGS bpf_helper_defs.h \
+ *.pc LIBBPF-CFLAGS $(OUTPUT)bpf_helper_defs.h \
$(SHARED_OBJDIR) $(STATIC_OBJDIR)
$(call QUIET_CLEAN, core-gen) $(RM) $(OUTPUT)FEATURE-DUMP.libbpf
--
2.24.1.735.g03f4e72817-goog
