[U-Boot] [PATCH] ARM1136: Align stack to 8 bytes

[Vitaly Kuzmichev]

Ok, but probably other ARM starters should be fixed too?
I have no possibility to check all ARM CPUs, but I believe this patch
won't break them.

On 06/15/2010 03:16 PM, Martin Krause wrote:
> Hi Vitaly,
> 
> the exact same problem applies to ARM1176. Maybe you could update
> your patch and add the same line to /arch/arm/cpu/arm1176/start.S.
> I am currently not working on an top-of-tree U-Boot, so it would
> be not so easy for me to create a separate patch for ARM1176.
> 
> Regards,
> Martin
> 
> u-boot-bounces at lists.denx.de wrote on Tuesday, June 15, 2010 12:52 PM:
>> The ARM ABI requires that the stack be aligned to 8 bytes as it is
>> noted in Procedure Call Standard for the ARM Architecture:
>> http://infocenter.arm.com/help/topic/com.arm.doc.ihi0042d/index.html
>>
>> Unaligned SP also causes the problem with variable-length arrays
>> allocation when VLA address becomes less than stack pointer during
>> aligning of this address, so the further 'push' into the stack
>> overwrites first 4 bytes of VLA.
>>
>> Signed-off-by: Vitaly Kuzmichev <vkuzmichev at mvista.com>
>> Signed-off-by: George G. Davis <gdavis at mvista.com>
>> ---
>>  arch/arm/cpu/arm1136/start.S |    1 +
>>  1 files changed, 1 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/arm/cpu/arm1136/start.S
>> b/arch/arm/cpu/arm1136/start.S index 957f438..d0c5717 100644
>> --- a/arch/arm/cpu/arm1136/start.S
>> +++ b/arch/arm/cpu/arm1136/start.S
>> @@ -185,6 +185,7 @@ stack_setup:
>>  #endif
>>  	sub	sp, r0, #12		/* leave 3 words for abort-stack    */
>>  #endif	/* CONFIG_PRELOADER */
>> +	bic	sp, sp, #7		/* 8-byte alignment                 */
>>
>>  clear_bss:
>>  	ldr	r0, _bss_start		/* find start of bss segment	    */