[PATCH] objtool: make use of pkg-config for libelf

[PATCH] objtool: make use of pkg-config for libelf

[Philipp Puschmann]

For libelf with non-standard paths make use of pkg-config.

Signed-off-by: Philipp Puschmann <pp@emlix.com>
---
 Makefile               | 4 +++-
 tools/objtool/Makefile | 8 ++++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index 659a7780aeb3..31b296b0e941 100644
--- a/Makefile
+++ b/Makefile
@@ -953,8 +953,10 @@ endif
 export mod_sign_cmd
 
 ifdef CONFIG_STACK_VALIDATION
+  LIBELF_LIBS = $(shell pkg-config --libs libelf 2> /dev/null || \
+                        echo -lelf)
   has_libelf := $(call try-run,\
-		echo "int main() {}" | $(HOSTCC) -xc -o /dev/null -lelf -,1,0)
+		echo "int main() {}" | $(HOSTCC) -xc -o /dev/null $(LIBELF_LIBS) -,1,0)
   ifeq ($(has_libelf),1)
     objtool_target := tools/objtool FORCE
   else
diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index e6acc281dd37..c565eff8c393 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -27,12 +27,16 @@ OBJTOOL_IN := $(OBJTOOL)-in.o
 
 all: $(OBJTOOL)
 
+LIBELF_LIBS     = $(shell pkg-config --libs libelf 2> /dev/null || \
+                        echo -lelf)
+LIBELF_INCLUDES = $(shell pkg-config --cflags libelf 2> /dev/null)
 INCLUDES := -I$(srctree)/tools/include \
 	    -I$(srctree)/tools/arch/$(HOSTARCH)/include/uapi \
-	    -I$(srctree)/tools/objtool/arch/$(ARCH)/include
+	    -I$(srctree)/tools/objtool/arch/$(ARCH)/include \
+	    $(LIBELF_INCLUDES)
 WARNINGS := $(EXTRA_WARNINGS) -Wno-switch-default -Wno-switch-enum -Wno-packed
 CFLAGS   += -Wall -Werror $(WARNINGS) -fomit-frame-pointer -O2 -g $(INCLUDES)
-LDFLAGS  += -lelf $(LIBSUBCMD)
+LDFLAGS  += $(LIBELF_LIBS) $(LIBSUBCMD)
 
 # Allow old libelf to be used:
 elfshdr := $(shell echo '\#include <libelf.h>' | $(CC) $(CFLAGS) -x c -E - | grep elf_getshdr)
-- 
2.16.1

Re: [PATCH] objtool: make use of pkg-config for libelf

[Josh Poimboeuf]

[ Adding Robin ]

Robin, does this fix the same issue as your recent patches?  If so, I'd
prefer this one because it doesn't need any new environment variables.

On Thu, Mar 01, 2018 at 01:55:37PM +0100, Philipp Puschmann wrote:
> For libelf with non-standard paths make use of pkg-config.
> 
> Signed-off-by: Philipp Puschmann <pp@emlix.com>
> ---
>  Makefile               | 4 +++-
>  tools/objtool/Makefile | 8 ++++++--
>  2 files changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/Makefile b/Makefile
> index 659a7780aeb3..31b296b0e941 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -953,8 +953,10 @@ endif
>  export mod_sign_cmd
>  
>  ifdef CONFIG_STACK_VALIDATION
> +  LIBELF_LIBS = $(shell pkg-config --libs libelf 2> /dev/null || \
> +                        echo -lelf)
>    has_libelf := $(call try-run,\
> -		echo "int main() {}" | $(HOSTCC) -xc -o /dev/null -lelf -,1,0)
> +		echo "int main() {}" | $(HOSTCC) -xc -o /dev/null $(LIBELF_LIBS) -,1,0)
>    ifeq ($(has_libelf),1)
>      objtool_target := tools/objtool FORCE
>    else
> diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
> index e6acc281dd37..c565eff8c393 100644
> --- a/tools/objtool/Makefile
> +++ b/tools/objtool/Makefile
> @@ -27,12 +27,16 @@ OBJTOOL_IN := $(OBJTOOL)-in.o
>  
>  all: $(OBJTOOL)
>  
> +LIBELF_LIBS     = $(shell pkg-config --libs libelf 2> /dev/null || \
> +                        echo -lelf)
> +LIBELF_INCLUDES = $(shell pkg-config --cflags libelf 2> /dev/null)
>  INCLUDES := -I$(srctree)/tools/include \
>  	    -I$(srctree)/tools/arch/$(HOSTARCH)/include/uapi \
> -	    -I$(srctree)/tools/objtool/arch/$(ARCH)/include
> +	    -I$(srctree)/tools/objtool/arch/$(ARCH)/include \
> +	    $(LIBELF_INCLUDES)
>  WARNINGS := $(EXTRA_WARNINGS) -Wno-switch-default -Wno-switch-enum -Wno-packed
>  CFLAGS   += -Wall -Werror $(WARNINGS) -fomit-frame-pointer -O2 -g $(INCLUDES)
> -LDFLAGS  += -lelf $(LIBSUBCMD)
> +LDFLAGS  += $(LIBELF_LIBS) $(LIBSUBCMD)
>  
>  # Allow old libelf to be used:
>  elfshdr := $(shell echo '\#include <libelf.h>' | $(CC) $(CFLAGS) -x c -E - | grep elf_getshdr)
> -- 
> 2.16.1
> 

-- 
Josh

Re: [PATCH] objtool: make use of pkg-config for libelf

[Robin Jarry]

2018-03-05, Josh Poimboeuf:
> [ Adding Robin ]
> 
> Robin, does this fix the same issue as your recent patches?  If so, I'd
> prefer this one because it doesn't need any new environment variables.

Hi Josh,

this looks like it would work. I need to do proper testing before
confirmation. Also, I did not have time to work on a v3. I'll wait a bit
to see where this goes first.

-- 
Robin