[tip:core/urgent] objtool: Fix Makefile to properly see if libelf is supported
From: tip-bot for Steven Rostedt
Date: Fri Apr 22 2016 - 05:46:37 EST
Commit-ID: c2bb9e32e2315971a8535fee77335c04a739d71d
Gitweb: http://git.kernel.org/tip/c2bb9e32e2315971a8535fee77335c04a739d71d
Author: Steven Rostedt <rostedt@xxxxxxxxxxx>
AuthorDate: Wed, 20 Apr 2016 11:32:35 -0400
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 22 Apr 2016 09:00:57 +0200
objtool: Fix Makefile to properly see if libelf is supported
When doing a make allmodconfig, I hit the following compile error:
In file included from builtin-check.c:32:0:
elf.h:22:18: fatal error: gelf.h: No such file or directory
compilation terminated.
...
Digging into it, it appears that the $(shell ..) command in the Makefile does
not give the proper result when it fails to find -lelf, and continues to
compile objtool.
Instead, use the "try-run" makefile macro to perform the test. This gives a
proper result for both cases.
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Bernd Petrovitsch <bernd@xxxxxxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Chris J Arges <chris.j.arges@xxxxxxxxxxxxx>
Cc: Jiri Slaby <jslaby@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Michal Marek <mmarek@xxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxx>
Cc: Pedro Alves <palves@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: live-patching@xxxxxxxxxxxxxxx
Fixes: 442f04c34a1a4 ("objtool: Add tool to perform compile-time stack metadata validation")
Link: http://lkml.kernel.org/r/20160420153234.GA24032@xxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
Makefile | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
index 1d0aef0..70ca38e 100644
--- a/Makefile
+++ b/Makefile
@@ -1008,7 +1008,8 @@ prepare0: archprepare FORCE
prepare: prepare0 prepare-objtool
ifdef CONFIG_STACK_VALIDATION
- has_libelf := $(shell echo "int main() {}" | $(HOSTCC) -xc -o /dev/null -lelf - &> /dev/null && echo 1 || echo 0)
+ has_libelf := $(call try-run,\
+ echo "int main() {}" | $(HOSTCC) -xc -o /dev/null -lelf -,1,0)
ifeq ($(has_libelf),1)
objtool_target := tools/objtool FORCE
else