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authorJoe Lawrence <joe.lawrence@redhat.com>2019-03-26 10:50:28 -0400
committerMasahiro Yamada <yamada.masahiro@socionext.com>2019-03-28 23:46:55 +0900
commit1a49b2fd8f58dd397043a17de9b3c421ccf8eda7 (patch)
treeb4180f6d758ea9439e7bc09786197d76c5cebccd /scripts/Makefile.build
parent156e7cbb3ef50d6d58b7975d79802e4ffb024dc2 (diff)
downloadlinux-1a49b2fd8f58dd397043a17de9b3c421ccf8eda7.tar.gz
kbuild: strip whitespace in cmd_record_mcount findstring
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>
Diffstat (limited to 'scripts/Makefile.build')
-rw-r--r--scripts/Makefile.build7
1 files changed, 2 insertions, 5 deletions
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 2554a15ecf2b..76ca30cc4791 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -199,11 +199,8 @@ 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)			\
-	fi
+cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)),	\
+	$(sub_cmd_record_mcount))
 endif # CC_USING_RECORD_MCOUNT
 endif # CONFIG_FTRACE_MCOUNT_RECORD