[PATCH] arm: relocate: Introduce data-only relocation mode

[Marek Vasut]

On 3/16/26 6:10 PM, Tom Rini wrote:

Hello Tom,

>>>> +config SKIP_RELOCATE_CODE
>>>> +	bool "Skips relocation of U-Boot code to end of RAM"
>>>> +	help
>>>> +	  Skips relocation of U-Boot code to the end of RAM, but still does
>>>> +	  relocate data to the end of RAM. This is mainly meant to relocate
>>>> +	  data to read-write portion of the RAM, while the code remains in
>>>> +	  read-only portion of the RAM from which it is allowed to execute.
>>>> +	  This split configuration is present on various secure cores.
>>>
>>> Is this really configurable, or is this determined by the SoC? This
>>> feels like something a board should be select'ing rather than
>>> configuring and I do worry about boards abusing this in the same of some
>>> possibly dubious speed-up rather than the intented and valid use case.
>>
>> On R-Car X5H, the Cortex-M core U-Boot port selects this, the Cortex-A core
>> U-Boot port does NOT select this. So, this is neither SoC level
>> configuration nor board level configuration, this is SoC CPU core level
>> configuration. I can definitely hide this symbol and conditionally select it
>> on SoC level.
> 
> At the high level, this sounds similar to the TI K3 platforms where we
> have a Cortex-R build and a Cortex-A build and so (ARCH_K3 && CPU_V7R)
> is valid in Kconfig. I assume there something similar in this situation,
> so yes please, thanks.
> 
>>> [snip]
>>>> diff --git a/arch/arm/lib/relocate.S b/arch/arm/lib/relocate.S
>>>> index 6ee58f4edfe..b6a648708f4 100644
>>>> --- a/arch/arm/lib/relocate.S
>>>> +++ b/arch/arm/lib/relocate.S
>>>> @@ -79,6 +79,15 @@ ENDPROC(relocate_vectors)
>>>>    ENTRY(relocate_code)
>>>>    relocate_base:
>>>>    	adr	r3, relocate_base
>>>> +
>>>> +#ifdef CONFIG_SKIP_RELOCATE_CODE
>>>> +	mov r4,	#CONFIG_SKIP_RELOCATE_CODE_DATA_OFFSET
>>>
>>> Spacing. But if there's no other comments and propmting the user is
>>> correct, I can fix when applying.
>> Fixed in V2 .
> 
> Thanks.
Either drop this patch and wait for V2, or I will send a follow up ?