Re: [PATCH v4 11/16] objtool: Add --mnop as an option to --mcount

Josh Poimboeuf
2022-10-11T20:33:41Z

On Mon, Oct 10, 2022 at 05:07:46PM +0530, Naveen N. Rao wrote:
> > +++ b/scripts/Makefile.lib
> > @@ -234,6 +234,7 @@ objtool_args = \
> > $(if $(CONFIG_HAVE_NOINSTR_HACK), --hacks=noinstr) \
> > $(if $(CONFIG_X86_KERNEL_IBT), --ibt) \
> > $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \
> > + $(if $(CONFIG_HAVE_OBJTOOL_NOP_MCOUNT), --mnop) \
>
> This still won't help: for instance, if CONFIG_FTRACE itself is disabled. I
> think we should make this depend on CONFIG_FTRACE_MCOUNT_USE_OBJTOOL. The
> below change works for me:
>
> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index 54d2d6451bdacc..fd3f55a1fdb7bb 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -245,8 +245,8 @@ objtool_args = \
> $(if $(CONFIG_HAVE_JUMP_LABEL_HACK), --hacks=jump_label) \
> $(if $(CONFIG_HAVE_NOINSTR_HACK), --hacks=noinstr) \
> $(if $(CONFIG_X86_KERNEL_IBT), --ibt) \
> - $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \
> - $(if $(CONFIG_HAVE_OBJTOOL_NOP_MCOUNT), --mnop) \
> + $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), \
> + $(if $(CONFIG_HAVE_OBJTOOL_NOP_MCOUNT), --mcount --mnop, --mcount)) \
> $(if $(CONFIG_UNWINDER_ORC), --orc) \
> $(if $(CONFIG_RETPOLINE), --retpoline) \
> $(if $(CONFIG_RETHUNK), --rethunk) \

This has a new conflict, may need something like:

--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -256,6 +256,9 @@ objtool-args-$(CONFIG_HAVE_JUMP_LABEL_HACK) += --hacks=jump_label
objtool-args-$(CONFIG_HAVE_NOINSTR_HACK) += --hacks=noinstr
objtool-args-$(CONFIG_X86_KERNEL_IBT) += --ibt
objtool-args-$(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL) += --mcount
+ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL
+objtool-args-$(CONFIG_HAVE_OBJTOOL_NOP_MCOUNT) += --mnop
+endif
objtool-args-$(CONFIG_UNWINDER_ORC) += --orc
objtool-args-$(CONFIG_RETPOLINE) += --retpoline
objtool-args-$(CONFIG_RETHUNK) += --rethunk