Re: [PATCH v2 1/2] ARM: setupc_32: remove relocation code from setup_c

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

Hello Sascha,

On 3/4/26 8:53 AM, Sascha Hauer wrote:
> All callers of setup_c() already call relocate_to_current_adr() or
> relocate_to_adr() before setup_c(), so the relocation (memcpy) code
> in setup_c is dead and also the sync_caches_for_execution() is unnecessary
> Remove it and reduce setup_c to just clearing BSS.

David reports this breaks his enclustra-sa2 and I observe also a hang on
Qemu Virt:

$ make multi_v7_defconfig
$ pytest --interactive
Using -bios device tree at 40000000
<hang>

Please drop from next, it's likely also what's breaking CI.

Cheers,
Ahmad

> 
> Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  arch/arm/cpu/setupc_32.S | 27 +++++----------------------
>  1 file changed, 5 insertions(+), 22 deletions(-)
> 
> diff --git a/arch/arm/cpu/setupc_32.S b/arch/arm/cpu/setupc_32.S
> index 0134637f62..c2c3f97528 100644
> --- a/arch/arm/cpu/setupc_32.S
> +++ b/arch/arm/cpu/setupc_32.S
> @@ -7,33 +7,16 @@
>  .section .text.setupc
>  
>  /*
> - * setup_c: copy binary to link address, clear bss and
> - * continue executing at new address.
> - *
> - * This function does not return to the address it is
> - * called from, but to the same location in the copied
> - * binary.
> + * setup_c: clear bss
>   */
>  ENTRY(setup_c)
> -	push	{r4, r5}
> -	mov	r5, lr
> -	bl	get_runtime_offset
> -	subs	r4, r0, #0
> -	beq	1f			/* skip memcpy if already at correct address */
> -	ldr	r0,=_text
> -	ldr	r2,=__bss_start
> -	sub	r2, r2, r0
> -	add	r1, r0, r4
> -	bl	__memcpy			/* memcpy(_text, _text + offset, __bss_start - _text) */
> -1:	ldr	r0, =__bss_start
> +	mov	r4, lr
> +	ldr	r0, =__bss_start
>  	mov	r1, #0
>  	ldr	r2, =__bss_stop
>  	sub	r2, r2, r0
> -	bl	__memset			/* clear bss */
> -	bl	sync_caches_for_execution
> -	sub	lr, r5, r4		/* adjust return address to new location */
> -	pop	{r4, r5}
> -	ret	lr
> +	bl	__memset		/* clear bss */
> +	ret	r4
>  ENDPROC(setup_c)
>  
>  /*
> 

-- 
Pengutronix e.K.                  |                             |
Steuerwalder Str. 21              | http://www.pengutronix.de/  |
31137 Hildesheim, Germany         | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686  | Fax:   +49-5121-206917-5555 |