[PATCH] objtool: Upgrade libelf-devel warning to error for CONFIG_ORC_UNWINDER

[Josh Poimboeuf]

With CONFIG_ORC_UNWINDER, if the user doesn't have libelf-devel
installed, and they don't see the make warning, their ORC unwinder will
be silently broken.  Upgrade the warning to an error.

Reported-and-tested-by: Borislav Petkov <bp@xxxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
 Makefile | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index cf007a31d575..5445cbf4d9a0 100644
--- a/Makefile
+++ b/Makefile
@@ -933,7 +933,11 @@ ifdef CONFIG_STACK_VALIDATION
   ifeq ($(has_libelf),1)
     objtool_target := tools/objtool FORCE
   else
-    $(warning "Cannot use CONFIG_STACK_VALIDATION, please install libelf-dev, libelf-devel or elfutils-libelf-devel")
+    ifdef CONFIG_ORC_UNWINDER
+      $(error "Cannot generate ORC metadata for CONFIG_ORC_UNWINDER, please install libelf-dev, libelf-devel or elfutils-libelf-devel")
+    else
+      $(warning "Cannot use CONFIG_STACK_VALIDATION, please install libelf-dev, libelf-devel or elfutils-libelf-devel")
+    endif
     SKIP_STACK_VALIDATION := 1
     export SKIP_STACK_VALIDATION
   endif
-- 
2.13.6