[U-Boot] [PATCH] arm: add 8-byte alignment for ABI compliance before board_init_f

[Heiko Schocher <hs@denx.de>]

Hello Reinhard,

Reinhard Meyer wrote:
> Dear Heiko Schocher,
>> diff --git a/arch/arm/cpu/sa1100/start.S b/arch/arm/cpu/sa1100/start.S
>> index ace0c07..91cdd72 100644
>> --- a/arch/arm/cpu/sa1100/start.S
>> +++ b/arch/arm/cpu/sa1100/start.S
>> @@ -152,6 +152,7 @@ reset:
>>   /* Set stackpointer in internal RAM to call board_init_f */
>>   call_board_init_f:
>>       ldr    sp, =(CONFIG_SYS_INIT_SP_ADDR)
>> +    bic    sp, sp, #7 /* 8-byte alignment for ABI compliance */
>>       ldr    r0,=0x00000000
>>       bl    board_init_f
>>
>> diff --git a/arch/arm/lib/board.c b/arch/arm/lib/board.c
>> index 1fd5f83..96c0e30 100644
>> --- a/arch/arm/lib/board.c
>> +++ b/arch/arm/lib/board.c
>> @@ -276,7 +276,7 @@ void board_init_f (ulong bootflag)
>>       ulong addr, addr_sp;
>>
>>       /* Pointer is writable since we allocated a register for it */
>> -    gd = (gd_t *) (CONFIG_SYS_INIT_SP_ADDR);
>> +    gd = (gd_t *) ((CONFIG_SYS_INIT_SP_ADDR)&  ~0x07);
>>       /* compiler optimization barrier needed for GCC>= 3.4 */
>>       __asm__ __volatile__("": : :"memory");
>>
> 
> Is bootflag ever used? If not, why not change the parameter to

No.

> give the gd address to board_init_f?
> 
>     ld r0, sp (whatever the exact assembly syntax for that would be)
> 
> void board_init_f (gd_t *gd_addr)
> ...
>     gd = gd_addr;

I thought this too, but in arch/powerpc/lib/board.c it is used as bootflag,
so I didn;t want to touch this ... but looking in arch/*/lib/board.c
this first parameter is not always used as bootflag ... so I think
that would be good ... opinions?

> One further thought, why not init the reserved register in assembly and
> remove the gd relevant code in C? But that bears some risk if the register
> is changed and the assembly is forgotten to adapt..

No, I think this is to risky ...

bye,
Heiko
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