[U-Boot] [PATCH] board_f.c: Insure gd->new_bootstage alignment

[Heinrich Schuchardt]

On 11/26/19 1:16 PM, Patrick DELAUNAY wrote:
> Hi,
>
>> From: Patrice CHOTARD <patrice.chotard at st.com>
>> Sent: lundi 25 novembre 2019 14:48
>>
>> In reserve_bootstage(), in case size is odd, gd->new_bootstage is not aligned. In
>> bootstage_relocate(), the platform hangs when getting access to data-
>>> record[i].name.
>> To avoid this issue, make gd->new_bootstage 16 byte aligned.
>>
>> Fixes: ac9cd4805c8b ("bootstage: Correct relocation algorithm")
>>
>> Signed-off-by: Patrice Chotard <patrice.chotard at st.com>
>> Reviewed-by: Vikas MANOCHA <vikas.manocha at st.com>
>> ---
>
> This patch is mandatory for stm32mp1 (ARM plaform with bootstage feature activated).
>
> Without this patch, the boot failed for v2020.01-rc3 (crash has struct pointer new_bootstage is not aligned).
>
> Reviewed-by: Patrick Delaunay <patrick.delaunay at st.com>
> Tested-by: Patrick Delaunay <patrick.delaunay at st.com>
>
>>   common/board_f.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/common/board_f.c b/common/board_f.c index e3591cbaeb..9cd4cfaf5f
>> 100644
>> --- a/common/board_f.c
>> +++ b/common/board_f.c
>> @@ -559,6 +559,7 @@ static int reserve_bootstage(void)
>>   	int size = bootstage_get_size();
>>
>>   	gd->start_addr_sp -= size;
>> +	gd->start_addr_sp = ALIGN_DOWN(gd->start_addr_sp, 16);

A comment in the code describing why this ALIGN_DOWN() is done would be
helpful.

Is this value sufficient for all boards?

I found references for:

x86_64 ABI: https://reviews.llvm.org/D30049: 16 bytes
ARMv8: ARMv8 Instruction Set Overview: quad word, 16 bytes

Best regards

Heinrich

>>   	gd->new_bootstage = map_sysmem(gd->start_addr_sp, size);
>>   	debug("Reserving %#x Bytes for bootstage at: %08lx\n", size,
>>   	      gd->start_addr_sp);
>> --
>> 2.17.1
>
> Thanks
>
> Patrick
>