Re: [PATCH v2 2/2] ARM: setup_c: avoid clearing BSS twice

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hi,

On 3/4/26 8:53 AM, Sascha Hauer wrote:
> Add a bss_cleared variable that is set after the first call to
> setup_c(). On subsequent calls, the BSS clear is skipped to avoid
> wiping already-initialized data.
> 
> Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

Minor point below:

> +.section .data

.data.bss_cleared or is it already in its own section?

> +bss_cleared:
> +	.word 	0
> +
>  /*
>   * void relocate_to_adr(unsigned long targetadr)
>   *
> diff --git a/arch/arm/cpu/setupc_64.S b/arch/arm/cpu/setupc_64.S
> index fd95187a04..caa16d3582 100644
> --- a/arch/arm/cpu/setupc_64.S
> +++ b/arch/arm/cpu/setupc_64.S
> @@ -7,19 +7,29 @@
>  .section .text.setupc
>  
>  /*
> - * setup_c: clear bss
> + * setup_c: clear bss if not yet done
>   */
>  ENTRY(setup_c)
> +	adr_l	x0, bss_cleared
> +	ldr	w1, [x0]
> +	cbnz	w1, 1f			/* skip if already done */
>  	mov	x15, x30
>  	adr_l	x0, __bss_start
>  	mov	x1, #0
>  	adr_l	x2, __bss_stop
>  	sub	x2, x2, x0
>  	bl	__memset		/* clear bss */
> +	adr_l	x0, bss_cleared
> +	mov	w1, #1
> +	str	w1, [x0]		/* mark bss cleared */
>  	mov	x30, x15
> -	ret
> +1:	ret
>  ENDPROC(setup_c)
>  
> +.section .data

Same question

> +bss_cleared:
> +	.word 	0
> +
>  /*
>   * void relocate_to_adr(unsigned long targetadr)
>   *
> 

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