[PATCH 1/1] sunxi: CONFIG_INIT_SP_RELATIVE=y for Pine64 LTS

[André Przywara]

On 02/06/2020 20:55, Tom Rini wrote:

Hi,

> On Tue, Jun 02, 2020 at 09:45:25PM +0200, Heinrich Schuchardt wrote:
>> On 6/2/20 5:51 PM, Tom Rini wrote:
>>> On Sun, May 31, 2020 at 10:43:00AM +0000, Heinrich Schuchardt wrote:
>>>
>>>> Booting pine64-lts_defconfig with either of CONFIG_RSA=y or CONFIG_LOG=y
>>>> fails if CONFIG_INIT_SP_RELATIVE is not set.
>>>>
>>>> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
>>>> ---
>>>>  configs/pine64-lts_defconfig | 3 +++
>>>>  1 file changed, 3 insertions(+)
>>>>
>>>> diff --git a/configs/pine64-lts_defconfig b/configs/pine64-lts_defconfig
>>>> index ef108a1a31..b03bef01b1 100644
>>>> --- a/configs/pine64-lts_defconfig
>>>> +++ b/configs/pine64-lts_defconfig
>>>> @@ -1,5 +1,8 @@
>>>>  CONFIG_ARM=y
>>>> +CONFIG_INIT_SP_RELATIVE=y
>>>>  CONFIG_ARCH_SUNXI=y
>>>> +CONFIG_SYS_MALLOC_F_LEN=0x8000
>>>> +CONFIG_SPL_SYS_MALLOC_F_LEN=0x400
>>>>  CONFIG_SPL=y
>>>>  CONFIG_MACH_SUN50I=y
>>>>  CONFIG_SUNXI_DRAM_LPDDR3_STOCK=y
>>>
>>> Look at the option however.  This is something that all sunxi should be
>>> selecting.
>>
>> What indicates that all sunxi should select CONFIG_INIT_SP_RELATIVE?
> 
> config INIT_SP_RELATIVE
>         bool "Specify the early stack pointer relative to the .bss section"
>         help
>           U-Boot typically uses a hard-coded value for the stack pointer
>           before relocation. Enable this option to instead calculate the
>           initial SP at run-time. This is useful to avoid hard-coding addresses
>           into U-Boot, so that it can be loaded and executed at arbitrary
>           addresses and thus avoid using arbitrary addresses at runtime.
> 
>           If this option is enabled, the early stack pointer is set to
>           &_bss_start with a offset value added. The offset is specified by
>           SYS_INIT_SP_BSS_OFFSET.
> 
> And that in turn tells me this is something that's done at the SoC
> level, especially for sunxi where things have been abstracted such that
> everyone (very roughly) shares the same board file, linker file, etc,
> and it's just defconfig+dts* files that change from board to board.

I agree on that, this particular defconfig change is generic to all
sunxi boards and we should fix this properly for the whole platform.

> So, to put it another way, what about the pine64-lts config is unique
> and causing this to be needed, but another arm64 sunxi platform would
> not?

I think were Heinrich came from is selecting CONFIG_RSA for his
particular build. I guess this requires a bigger malloc area. Now this
somehow collides which how we calculate the stack pointer, but it is too
late here to really track this down ;-)

Heinrich, can you please give an explanation what problem
CONFIG_INIT_SP_RELATIVE fixed and why? It seems like to cause some side
effect, but does not sound like the proper solution (because this is
more mean for the position independent build option).

Cheers,
Andre