Re: [PATCH] kbuild: Parameterize kallsyms generation and correct reporting

Kees Cook
2019-08-13T15:17:09Z

On Wed, Aug 14, 2019 at 12:00:05AM +0900, Masahiro Yamada wrote:
> On Tue, Aug 13, 2019 at 6:49 AM Kees Cook <keescook@chromium.org> wrote:
> >
> > When kallsyms generation happens, temporary vmlinux outputs are linked
> > but the quiet make output doesn't report it, giving the impression that
> > the prior command is taking longer than expected.
> >
> > Instead, report the KSYM step before the temporary linking. While at it,
> > this consolidates the repeated "kallsyms generation step" into a single
> > function and removes the existing copy/pasting.
> >
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
>
> Hmm, I did not notice this.

He either until I was getting link errors from MODINFO :)

> How about showing the link stage explicitly?
> (Is it too verbose?)
>
> MODINFO modules.builtin.modinfo
> LD .tmp_vmlinux1
> KSYMS .tmp_kallsyms1.o
> LD .tmp_vmlinux2
> KSYMS .tmp_kallsyms2.o
> LD vmlinux
> SORTEX vmlinux

I'm fine with this -- it's probably the right thing to do since getting
vmlinux link errors fro KSYMS probably doesn't make sense either. ;)

> If this verbosity is OK,
> you can move 'info LD ${2}' into vmlinux_link()

Done.

> Anyway, I like the clean-ups in this patch.
>
> This is just my personal preference, but
> may I ask two cosmetic changes?
>
> [1] Could you move kallsyms_step()
> between kallsyms() and mksysmap() ?
> I want to collect function definitions
> to the top of the script.
>
> [2] Could you shorten 'kallsymso_previous'
> to 'kallsymso_prev' ?

Sounds good. v2 sent.

--
Kees Cook