[PATCH AUTOSEL 4.14 52/59] kbuild: fix false positive warning/error about missing libelf

Sasha Levin
2018-12-26T22:42:28Z

From: Masahiro Yamada <yamada.masahiro@socionext.com>

[ Upstream commit ef7cfd00b2caf6edeb7f169682b64be2d0a798cf ]

For the same reason as commit 25896d073d8a ("x86/build: Fix compiler
support check for CONFIG_RETPOLINE"), you cannot put this $(error ...)
into the parse stage of the top Makefile.

Perhaps I'd propose a more sophisticated solution later, but this is
the best I can do for now.

Link: https://lkml.org/lkml/2017/12/25/211
Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Reported-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reported-by: Qian Cai <cai@lca.pw>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Qian Cai <cai@lca.pw>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
Makefile | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index 280c7193e246..f72fb4b403b7 100644
--- a/Makefile
+++ b/Makefile
@@ -954,11 +954,6 @@ ifdef CONFIG_STACK_VALIDATION
ifeq ($(has_libelf),1)
objtool_target := tools/objtool FORCE
else
- ifdef CONFIG_UNWINDER_ORC
- $(error "Cannot generate ORC metadata for CONFIG_UNWINDER_ORC=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel")
- else
- $(warning "Cannot use CONFIG_STACK_VALIDATION=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel")
- endif
SKIP_STACK_VALIDATION := 1
export SKIP_STACK_VALIDATION
endif
@@ -1102,6 +1097,14 @@ uapi-asm-generic:

PHONY += prepare-objtool
prepare-objtool: $(objtool_target)
+ifeq ($(SKIP_STACK_VALIDATION),1)
+ifdef CONFIG_UNWINDER_ORC
+ @echo "error: Cannot generate ORC metadata for CONFIG_UNWINDER_ORC=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel" >&2
+ @false
+else
+ @echo "warning: Cannot use CONFIG_STACK_VALIDATION=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel" >&2
+endif
+endif

# Check for CONFIG flags that require compiler support. Abort the build
# after .config has been processed, but before the kernel build starts.
--
2.19.1