[PATCH] arm64: Properly clear BSS

[brock.zheng]

i am glad to see my patch been reviewed.

I can not access the international network easily.
so any of you can fix / rewrite / change that patch.

If I can see the fixup in the offical git repo, I will be very very glad.


On 2025-09-02 09:08:12, Ilias Apalodimas wrote:
> Date: Tue,  2 Sep 2025 09:08:12 +0300
> From: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> To: trini at konsulko.com
> Cc: heinrich.schuchardt at canonical.com,  Ilias Apalodimas
>  <ilias.apalodimas at linaro.org>, brock_zheng <yzheng at techyauld.com>,  Simon
>  Glass <sjg at chromium.org>, Marek Vasut <marek.vasut+renesas at mailbox.org>,
>   u-boot at lists.denx.de
> Subject: [PATCH] arm64: Properly clear BSS
> X-Mailer: git-send-email 2.50.1
> 
> Brock reports a breakage on an RK3568 SoC. His patch is
> correct but he never followed up on the requested changes.
> 
> We currently use ldr to calculate the address of __bss_start and
> __bss_end. However the absolute addresses of the literal pool are never
> relocated and we end up clearing the wrong memory section. Use
> PC-relative addressing instead.
> 
> Link: https://lore.kernel.org/u-boot/zfknlzcemnnaka5w2er5wjwefwoidrpndc4gjhx6d5xr6nlcjr@pasfayjiutii/
> 
> Suggested-by: brock_zheng <yzheng at techyauld.com>
> Reported-by: brock_zheng <yzheng at techyauld.com>
> Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> ---
>  arch/arm/lib/crt0_64.S | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/lib/crt0_64.S b/arch/arm/lib/crt0_64.S
> index f3f279f2c39c..3e7627aa389b 100644
> --- a/arch/arm/lib/crt0_64.S
> +++ b/arch/arm/lib/crt0_64.S
> @@ -158,8 +158,10 @@ relocation_return:
>  /*
>   * Clear BSS section
>   */
> -	ldr	x0, =__bss_start		/* this is auto-relocated! */
> -	ldr	x1, =__bss_end			/* this is auto-relocated! */
> +	adrp	x0, __bss_start
> +	add	x0, x0, #:lo12:__bss_start
> +	adrp	x1, __bss_end
> +	add	x1, x1, #:lo12:__bss_end
>  clear_loop:
>  	str	xzr, [x0], #8
>  	cmp	x0, x1
> -- 
> 2.50.1
> 
> 
> 

-- 
Brock Zheng <yzheng at techyauld.com>