[PATCH v2] objtool: query pkg-config for libelf location

From: Rolf Eike Beer
Date: Wed Mar 20 2019 - 11:58:33 EST


If it is not in the default location compilation would fail at several points.

Signed-off-by: Rolf Eike Beer <eb@xxxxxxxxx>
---
Changes in v2:
-also hide stderr when querying cflags
-use ":=" assignment as in other places in that file

Makefile | 4 +++-
tools/objtool/Makefile | 7 +++++--
2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index 99c0530489ef..32caf30e0d79 100644
--- a/Makefile
+++ b/Makefile
@@ -950,9 +950,11 @@ mod_sign_cmd = true
endif
export mod_sign_cmd

+HOST_LIBELF_LIBS = $(shell pkg-config libelf --libs 2>/dev/null || echo -lelf)
+
ifdef CONFIG_STACK_VALIDATION
has_libelf := $(call try-run,\
- echo "int main() {}" | $(HOSTCC) -xc -o /dev/null -lelf -,1,0)
+ echo "int main() {}" | $(HOSTCC) -xc -o /dev/null $(HOST_LIBELF_LIBS) -,1,0)
ifeq ($(has_libelf),1)
objtool_target := tools/objtool FORCE
else
diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index c9d038f91af6..53f8be0f4a1f 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -25,14 +25,17 @@ LIBSUBCMD = $(LIBSUBCMD_OUTPUT)libsubcmd.a
OBJTOOL := $(OUTPUT)objtool
OBJTOOL_IN := $(OBJTOOL)-in.o

+LIBELF_FLAGS := $(shell pkg-config libelf --cflags 2>/dev/null)
+LIBELF_LIBS := $(shell pkg-config libelf --libs 2>/dev/null || echo -lelf)
+
all: $(OBJTOOL)

INCLUDES := -I$(srctree)/tools/include \
-I$(srctree)/tools/arch/$(HOSTARCH)/include/uapi \
-I$(srctree)/tools/objtool/arch/$(ARCH)/include
WARNINGS := $(EXTRA_WARNINGS) -Wno-switch-default -Wno-switch-enum -Wno-packed
-CFLAGS += -Werror $(WARNINGS) $(KBUILD_HOSTCFLAGS) -g $(INCLUDES)
-LDFLAGS += -lelf $(LIBSUBCMD) $(KBUILD_HOSTLDFLAGS)
+CFLAGS += -Werror $(WARNINGS) $(KBUILD_HOSTCFLAGS) -g $(INCLUDES) $(LIBELF_FLAGS)
+LDFLAGS += $(LIBELF_LIBS) $(LIBSUBCMD) $(KBUILD_HOSTLDFLAGS)

# Allow old libelf to be used:
elfshdr := $(shell echo '$(pound)include <libelf.h>' | $(CC) $(CFLAGS) -x c -E - | grep elf_getshdr)
--
2.21.0

--
Rolf Eike Beer, emlix GmbH, http://www.emlix.com
Fon +49 551 30664-0, Fax +49 551 30664-11
Gothaer Platz 3, 37083 GÃttingen, Germany
Sitz der Gesellschaft: GÃttingen, Amtsgericht GÃttingen HR B 3160
GeschÃftsfÃhrung: Heike Jordan, Dr. Uwe Kracke â Ust-IdNr.: DE 205 198 055

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