[PATCH 2/5] arm64: initialize the frame pointer register

[Ilias Apalodimas]

On Thu, 3 Jul 2025 at 08:20, Heinrich Schuchardt
<heinrich.schuchardt at canonical.com> wrote:
>
> U-Boot may be compiled with frame pointers depending on defaults built into
> compilers are via explicitly passing -fno-omit-frame-pointer.
>
> To stop walking frames it is necessary that the initial value of the frame
> pointer register is 0.
>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>

Reviewed-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> ---
>  arch/arm/lib/crt0_64.S | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm/lib/crt0_64.S b/arch/arm/lib/crt0_64.S
> index f3f279f2c39..3ff0577e9c8 100644
> --- a/arch/arm/lib/crt0_64.S
> +++ b/arch/arm/lib/crt0_64.S
> @@ -168,6 +168,7 @@ clear_loop:
>         /* call board_init_r(gd_t *id, ulong dest_addr) */
>         mov     x0, x18                         /* gd_t */
>         ldr     x1, [x18, #GD_RELOCADDR]        /* dest_addr */
> +       mov     x29, 0                          /* frame pointer */
>         b       board_init_r                    /* PC relative jump */
>
>         /* NOTREACHED - board_init_r() does not return */
> --
> 2.48.1
>