[PATCH] kbuild: strip whitespace in cmd_record_mcount findstring

From: Joe Lawrence
Date: Mon Mar 25 2019 - 12:05:00 EST


CC_FLAGS_FTRACE may contain trailing whitespace that interferes with
findstring.

For example, commit 6977f95e63b9 ("powerpc: avoid -mno-sched-epilog on
GCC 4.9 and newer") introduced a change such that on my ppc64le box,
CC_FLAGS_FTRACE="-pg -mprofile-kernel ". (Note the trailing space.)
When cmd_record_mcount is now invoked, findstring fails as the ftrace
flags were found at very end of _c_flags, without the trailing space.

_c_flags=" ... -pg -mprofile-kernel"
CC_FLAGS_FTRACE="-pg -mprofile-kernel "
^
findstring is looking for this extra space

Remove the redundant whitespaces from CC_FLAGS_FTRACE in
cmd_record_mcount to avoid this problem.

Fixes: 6977f95e63b9 ("powerpc: avoid -mno-sched-epilog on GCC 4.9 and newer").
Signed-off-by: Joe Lawrence <joe.lawrence@xxxxxxxxxx>
---

Standard disclaimer: I'm not a kbuild expert, but this works around the
problem I reported where ftrace and livepatch self-tests were failing as
specified object files were not run through the recordmcount.pl script:

ppc64le: ftrace self-tests and $(CC_FLAGS_FTRACE) broken?
https://lists.ozlabs.org/pipermail/linuxppc-dev/2019-March/187298.html

scripts/Makefile.build | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 2554a15ecf2b..74d402b5aa3c 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -199,10 +199,10 @@ sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
"$(if $(part-of-module),1,0)" "$(@)";
recordmcount_source := $(srctree)/scripts/recordmcount.pl
endif # BUILD_C_RECORDMCOUNT
-cmd_record_mcount = \
- if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" = \
- "$(CC_FLAGS_FTRACE)" ]; then \
- $(sub_cmd_record_mcount) \
+cmd_record_mcount = \
+ if [ "$(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags))" = \
+ "$(strip $(CC_FLAGS_FTRACE))" ]; then \
+ $(sub_cmd_record_mcount) \
fi
endif # CC_USING_RECORD_MCOUNT
endif # CONFIG_FTRACE_MCOUNT_RECORD
--
2.20.1