On Mon, 25 Mar 2019 12:04:38 -0400
Joe Lawrence <joe.lawrence@xxxxxxxxxx> wrote:
> 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
Wow, what a bug.
>
> 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>
Acked-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
-- Steve
> ---
>
> 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
