[PATCH] ARM: imx: Enable kaslrseed command on DH i.MX8M Plus DHCOM

[Marek Vasut]

On 4/19/24 5:24 PM, Tim Harvey wrote:
> On Thu, Apr 18, 2024 at 11:42 AM Marek Vasut <marex at denx.de> wrote:
>>
>> On 4/18/24 8:02 PM, Fabio Estevam wrote:
>>> Hi Tim,
>>>
>>> On Thu, Apr 18, 2024 at 2:54 PM Tim Harvey <tharvey at gateworks.com> wrote:
>>>
>>>> Fabio, if you enable CONFIG_DM_RNG on an imx8m{m,p}_evk do you get the
>>>> following in the SPL?
>>>> Couldn't bind rng driver (-96)
>>>> SEC0:  RNG instantiated
>>>>
>>>> sec_init failed!
>>>
>>> Yes, if I add CONFIG_DM_RNG=y to imx8mm_evk_defconfig I get:
>>>
>>> U-Boot SPL 2024.04-00793-g3434b88d2c2f-dirty (Apr 18 2024 - 14:58:57 -0300)
>>> No pmic
>>> Couldn't bind rng driver (-96)
>>> SEC0:  RNG instantiated
>>>
>>> sec_init failed!
>>
>> Interesting. Which TFA blob version do you use ? I used the mainline
>> 2.10 for my tests.
> 
> Marek,
> 
> Were you able to reproduce this as well with the board you enabled
> DM_RNG for? If it does work fine what dtb were you using... perhaps
> there is something in its u-boot.dtsi that we need?

This one arch/arm/dts/imx8mp-dhcom-pdk3.dts , see log below. The build 
has a few extra patches in it, but nothing which affects the KASLR:

$ export SOURCE_DATE_EPOCH=1672531200 ; echo tst > .scmversion
$ make imx8mp_dhcom_pdk3_defconfig ; make

U-Boot SPL 2024.07-rc1tst (Jan 01 2023 - 00:00:00 +0000)
DDR:   4096 MiB [0x5]
DDR:   Inline ECC enabled
WDT:   Started watchdog at 30280000 with servicing every 1000ms (60s timeout)
Trying to boot from BOOTROM
Boot Stage: Primary boot
image offset 0x1000, pagesize 0x1, ivt offset 0x0
NOTICE:  Do not release JR0 to NS as it can be used by HAB
NOTICE:  BL31: v2.10.0  (release):v2.10.0-5-gfb51ca229
NOTICE:  BL31: Built : 20:30:36, Apr 23 2024


U-Boot 2024.07-rc1tst (Jan 01 2023 - 00:00:00 +0000)

CPU:   Freescale i.MX8MP[8] rev1.1 1600 MHz (running at 1200 MHz)
CPU:   Industrial temperature grade (-40C to 105C) at 70C
Reset cause: POR
Model: DH electronics i.MX8M Plus DHCOM Premium Developer Kit (3)
DRAM:  3.5 GiB
Core:  183 devices, 34 uclasses, devicetree: separate
WDT:   Started watchdog at 30280000 with servicing every 1000ms (60s timeout)
MMC:   FSL_SDHC: 0, FSL_SDHC: 1
Loading Environment from SPIFlash... SF: Detected w25q128jw with page 
size 256 Bytes, erase size 4 KiB, total 16 MiB
OK
In:    serial
Out:   serial
Err:   serial
SEC0:  RNG instantiated
Net:   eth1: ethernet at 30be0000, eth0: ethernet at 30bf0000
...

> The error -EPFNOSUPPORT is interesting and helps point to the only
> place it can be where the comment says the strange errno is to make
> this easier to find:
> https://elixir.bootlin.com/u-boot/latest/source/drivers/core/uclass.c#L70:
>          if (!uc_drv) {
>                  debug("Cannot find uclass for id %d: please add the
> UCLASS_DRIVER() declaration for this UCLASS_... id\n",
>                        id);
>                  /*
>                   * Use a strange error to make this case easier to find. When
>                   * a uclass is not available it can prevent driver model from
>                   * starting up and this failure is otherwise hard to debug.
>                   */
>                  return -EPFNOSUPPORT;
>          }
> 
> I'm not very familiar with the dm driver binding - does the
> U-BOOT_DRIVER usage in drivers/crypto/fsl/rng.c need to be refactored
> to use UCLASS_DRIVER for it to be usable in both SPL and U-Boot?

I don't think you need the CAAM RNG in SPL in the first place, or do you ?

> Honestly I don't know why we need DM_RNG in SPL anyway and we could
> just add support for disabling it there to avoid unwanted bloat.

I think you can disable it , yes.