From 1a49b2fd8f58dd397043a17de9b3c421ccf8eda7 Mon Sep 17 00:00:00 2001
From: Joe Lawrence <joe.lawrence@redhat.com>
Date: Tue, 26 Mar 2019 10:50:28 -0400
Subject: [PATCH] kbuild: strip whitespace in cmd_record_mcount findstring

References: bsc#1065729
Patch-mainline: v5.1-rc3
Git-commit: 1a49b2fd8f58dd397043a17de9b3c421ccf8eda7

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.

[masahiro.yamada: This issue only happens in the released versions
of GNU Make. CC_FLAGS_FTRACE will not contain the trailing space if
you use the latest GNU Make, which contains commit b90fabc8d6f3
("* NEWS: Do not insert a space during '+=' if the value is empty.") ]

Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> (refactoring)
Fixes: 6977f95e63b9 ("powerpc: avoid -mno-sched-epilog on GCC 4.9 and newer").
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 scripts/Makefile.build | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -246,11 +246,8 @@ sub_cmd_record_mcount = set -e ; perl $(
 	"$(if $(part-of-module),1,0)" "$(@)";
 recordmcount_source := $(srctree)/scripts/recordmcount.pl
 endif
-cmd_record_mcount =						\
-	if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" =	\
-	     "$(CC_FLAGS_FTRACE)" ]; then			\
-		$(sub_cmd_record_mcount)			\
-	fi;
+cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)),	\
+	$(sub_cmd_record_mcount))
 endif
 
 ifdef CONFIG_STACK_VALIDATION