1 files changed, 30 insertions, 17 deletions

diff --git a/tools/bpf/resolve_btfids/Makefile b/tools/bpf/resolve_btfids/Makefile
index 19a3112e271a..ac548a7baa73 100644
--- a/tools/bpf/resolve_btfids/Makefile
+++ b/tools/bpf/resolve_btfids/Makefile
@@ -17,15 +17,15 @@ else
   MAKEFLAGS=--no-print-directory
 endif
 
-# always use the host compiler
-AR       = $(HOSTAR)
-CC       = $(HOSTCC)
-LD       = $(HOSTLD)
-ARCH     = $(HOSTARCH)
+# Overrides for the prepare step libraries.
+HOST_OVERRIDES := AR="$(HOSTAR)" CC="$(HOSTCC)" LD="$(HOSTLD)" ARCH="$(HOSTARCH)" \
+		  CROSS_COMPILE="" EXTRA_CFLAGS="$(HOSTCFLAGS)"
+
 RM      ?= rm
+HOSTCC  ?= gcc
+HOSTLD  ?= ld
+HOSTAR  ?= ar
 CROSS_COMPILE =
-CFLAGS  := $(KBUILD_HOSTCFLAGS)
-LDFLAGS := $(KBUILD_HOSTLDFLAGS)
 
 OUTPUT ?= $(srctree)/tools/bpf/resolve_btfids/
 
@@ -35,51 +35,64 @@ SUBCMD_SRC := $(srctree)/tools/lib/subcmd/
 BPFOBJ     := $(OUTPUT)/libbpf/libbpf.a
 LIBBPF_OUT := $(abspath $(dir $(BPFOBJ)))/
 SUBCMDOBJ  := $(OUTPUT)/libsubcmd/libsubcmd.a
+SUBCMD_OUT := $(abspath $(dir $(SUBCMDOBJ)))/
 
 LIBBPF_DESTDIR := $(LIBBPF_OUT)
 LIBBPF_INCLUDE := $(LIBBPF_DESTDIR)include
 
+SUBCMD_DESTDIR := $(SUBCMD_OUT)
+SUBCMD_INCLUDE := $(SUBCMD_DESTDIR)include
+
 BINARY     := $(OUTPUT)/resolve_btfids
 BINARY_IN  := $(BINARY)-in.o
 
 all: $(BINARY)
 
+prepare: $(BPFOBJ) $(SUBCMDOBJ)
+
 $(OUTPUT) $(OUTPUT)/libsubcmd $(LIBBPF_OUT):
 	$(call msg,MKDIR,,$@)
 	$(Q)mkdir -p $(@)
 
 $(SUBCMDOBJ): fixdep FORCE | $(OUTPUT)/libsubcmd
-	$(Q)$(MAKE) -C $(SUBCMD_SRC) OUTPUT=$(abspath $(dir $@))/ $(abspath $@)
+	$(Q)$(MAKE) -C $(SUBCMD_SRC) OUTPUT=$(SUBCMD_OUT) \
+		    DESTDIR=$(SUBCMD_DESTDIR) $(HOST_OVERRIDES) prefix= subdir= \
+		    $(abspath $@) install_headers
 
 $(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OUT)
 	$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) OUTPUT=$(LIBBPF_OUT)    \
-		    DESTDIR=$(LIBBPF_DESTDIR) prefix= EXTRA_CFLAGS="$(CFLAGS)" \
+		    DESTDIR=$(LIBBPF_DESTDIR) $(HOST_OVERRIDES) prefix= subdir= \
 		    $(abspath $@) install_headers
 
-CFLAGS += -g \
+LIBELF_FLAGS := $(shell $(HOSTPKG_CONFIG) libelf --cflags 2>/dev/null)
+LIBELF_LIBS  := $(shell $(HOSTPKG_CONFIG) libelf --libs 2>/dev/null || echo -lelf)
+
+HOSTCFLAGS += -g \
           -I$(srctree)/tools/include \
           -I$(srctree)/tools/include/uapi \
           -I$(LIBBPF_INCLUDE) \
-          -I$(SUBCMD_SRC)
+          -I$(SUBCMD_INCLUDE) \
+          $(LIBELF_FLAGS)
 
-LIBS = -lelf -lz
+LIBS = $(LIBELF_LIBS) -lz
 
-export srctree OUTPUT CFLAGS Q
+export srctree OUTPUT HOSTCFLAGS Q HOSTCC HOSTLD HOSTAR
 include $(srctree)/tools/build/Makefile.include
 
-$(BINARY_IN): $(BPFOBJ) fixdep FORCE | $(OUTPUT)
+$(BINARY_IN): fixdep FORCE prepare | $(OUTPUT)
 	$(Q)$(MAKE) $(build)=resolve_btfids
 
 $(BINARY): $(BPFOBJ) $(SUBCMDOBJ) $(BINARY_IN)
 	$(call msg,LINK,$@)
-	$(Q)$(CC) $(BINARY_IN) $(LDFLAGS) -o $@ $(BPFOBJ) $(SUBCMDOBJ) $(LIBS)
+	$(Q)$(HOSTCC) $(BINARY_IN) $(KBUILD_HOSTLDFLAGS) -o $@ $(BPFOBJ) $(SUBCMDOBJ) $(LIBS)
 
 clean_objects := $(wildcard $(OUTPUT)/*.o                \
                             $(OUTPUT)/.*.o.cmd           \
                             $(OUTPUT)/.*.o.d             \
                             $(LIBBPF_OUT)                \
                             $(LIBBPF_DESTDIR)            \
-                            $(OUTPUT)/libsubcmd          \
+                            $(SUBCMD_OUT)                \
+                            $(SUBCMD_DESTDIR)            \
                             $(OUTPUT)/resolve_btfids)
 
 ifneq ($(clean_objects),)
@@ -96,4 +109,4 @@ tags:
 
 FORCE:
 
-.PHONY: all FORCE clean tags
+.PHONY: all FORCE clean tags prepare