Re: [PATCH] MODSIGN: Change default key details [ver #2]

[Linus Torvalds]

On Fri, May 1, 2015 at 2:41 PM, Abelardo Ricart III <aricart@xxxxxxxxxx> wrote:
>
> Here's my two-line patch strictly defining the build order, for your perusal.

Ok, so this looks possible and sounds like it could explain the issues.

But I'd like somebody who is much more familiar with these kinds of
subtleties in 'make' to take anothe rlook and ack it. Because I had
personally never even heard (much less used) about these magical GNU
make "order-only prerequisites". Live and learn.

> -signing_key.priv signing_key.x509: x509.genkey
> +signing_key.priv signing_key.x509: | x509.genkey
> +       $(warning *** X.509 module signing key pair not found in root of source tree ***)

So we shouldn't warn about this. The "generate random key" should be
the normal action for just about everybody but actual preduction
vendor builds. It's definitely not an error condition.

But that ": |" syntax is interesting. I quick grep does show that we
do have a few previous uses, so I guess we really *do* use just about
every possible feature of GNU make even if I wasn't aware of this
one..

The "generate random key" does seem to be a similar "prep" phase as
the __dtbs_install_prep thing we do in the dtb install.

Adding Michal Marek to the cc, since I want an Ack from somebody who
knows the details of GNU make more than I do.  Anybody else who is a
makefile God?

                    Linus
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