[PATCH v2] drivers: crypto: mod_exp_sw: Re-add DM_FLAG_PRE_RELOC

[Heinrich Schuchardt]

On 22.05.20 14:21, Jan Kiszka wrote:
> On 22.05.20 13:38, Heinrich Schuchardt wrote:
>> Am May 22, 2020 10:50:29 AM UTC schrieb Jan Kiszka <jan.kiszka at siemens.com>:
>>> On 22.05.20 12:42, Heinrich Schuchardt wrote:
>>>> On 5/20/20 2:22 PM, Tom Rini wrote:
>>>>> On Thu, May 07, 2020 at 08:36:03PM +0200, Jan Kiszka wrote:
>>>>>
>>>>>> From: Jan Kiszka <jan.kiszka at siemens.com>
>>>>>>
>>>>>> This driver is safe to use in SPL without relocation. Denying
>>>>>> DM_FLAG_PRE_RELOC prevents its usability for verifying the main
>>> U-Boot
>>>>>> or other artifacts from the SPL unless needless enabling the full
>>> driver
>>>>>> set (SPL_OF_PLATDATA).
>>>>>>
>>>>>> Fixes: 17e117408571 ("drivers: crypto: rsa_mod_exp: avoid
>>> DM_FLAG_PRE_RELOC")
>>>>>> CC: Heinrich Schuchardt <xypron.glpk at gmx.de>
>>>>>> CC: Marek Vasut <marex at denx.de>
>>>>>> Signed-off-by: Jan Kiszka <jan.kiszka at siemens.com>
>>>>>
>>>>> Applied to u-boot/master, thanks!
>>>>>
>>>>
>>>> With this patch applied pine64-lts_defconfig with CONFIG_RSA=y does
>>> not
>>>> boot anymore. See the output below. So something is wrong with this
>>> driver.
>>>>
>>>> Do you have an idea how to analyze what is wrong? Unfortunately there
>>> is
>>>> no DEBUG_UART available on the Pine A64 LTS board.
>>>
>>> I would start crippling it down until things start to boot again. Are
>>> you using it (for image verification e.g.), or is this just the
>>> registration that breaks already?
>>>
>>
>>
>> RSA is needed in the UEFI subsystem for verifying variables and images. But there is no need in SPL for it at all.
>>
>> In my configuration RSA is not used at all. Something breaks before even the console becomes available.
>>
>> The pine64-lts_defconfig board boots via SPL->BL31->U-Boot
>
> But then a workaround for you would be to turn this driver off in SPL.
> UEFI is main U-Boot only, isn't it?
>
> That said, understanding the reason for the breakage would still be nice
> for the case someone needs to validate what SPL loads with the help of
> RSA (which is the case for us on an AM65x board).
>
> Jan
>
As I described above I did *not* select RSA_SPL. The breakage is in main
U-boot. SPL works fine loading TF-A BL31 which in turn loads U-Boot. But
during driver initialization U-Boot does not even reach the point where
we have a console due to something wrong with DM_FLAG_PRE_RELOC.

Best regards

Heinrich