[PATCH 4/4] kbuild: arm: Fix duplicate builds of dtbs

[Jan Kiszka]

On 08.05.20 17:40, Andrew F. Davis wrote:
> On 5/4/20 8:38 AM, Jan Kiszka wrote:
>> From: Jan Kiszka <jan.kiszka at siemens.com>
>>
>> Build the secured board dtbs (.dtb_HS) as part of the regular dtb build
>> on CONFIG_TI_SECURE_DEVICE targets. This avoids rebuilding them,
>> possibly overwriting artifacts that are in use, as it is done so far.
>>
>> In the same run, fix needless rebuilding of the secured spl dtb.
>>
>> Fixes: 508369672ca3 ("arm: mach-k3: Add secure device build support")
>> CC: Andrew F. Davis <afd at ti.com>
>> Signed-off-by: Jan Kiszka <jan.kiszka at siemens.com>
>> ---
>>   arch/arm/dts/Makefile             |  6 ++++--
>>   arch/arm/mach-k3/config_secure.mk | 19 ++++++++++++++-----
>>   2 files changed, 18 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
>> index 2c123bd6da..b68e9c0726 100644
>> --- a/arch/arm/dts/Makefile
>> +++ b/arch/arm/dts/Makefile
>> @@ -1,5 +1,7 @@
>>   # SPDX-License-Identifier: GPL-2.0+
>>
>> +include $(srctree)/arch/arm/mach-k3/config_secure.mk
>> +
>
>
> This is hacky, we should not in the top level dts makefile have a
> dependency on a specific platform configuration file.
>
> What about mach-omap/config_secure.mk, etc..

They don't need those special signing the k3 need. If they did, they
could be included here as well.

>
> The negative of building dtbs twice for HS is very minor compared to the
> extra complexity this patch adds. It will be much more difficult to
> clean this up later.

Overwriting a build artifacts that were already completed and may just
be in use while doing so is broken. This must be fixed.

As I wrote, I will add support for injecting public keys into the dtbs,
and that also revealed this issue.

Better suggestions welcome.

Jan