Re: [Xen-devel] [PATCH] ARM/boot: Don't poison 'current' during early boot

[Julien Grall <julien@xxxxxxx>]

Hi,

On 15/01/2020 18:43, Andrew Cooper wrote:
> This logic was inherited from x86 (which was updated several times since).
> Unlike x86 (at the time) however, while NULL isn't mapped in ARM, 0xfffff000
> is, making this actively dangerous.
>
> Drop the logic entirely, and leave 'current' as NULL during early boot.
>
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Thank you for the cleanup!

Acked-by: Julien Grall <julien@xxxxxxx>

Cheers,

> ---
> CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> CC: Julien Grall <julien@xxxxxxx>
> CC: Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
> ---
>   xen/arch/arm/setup.c | 3 ---
>   1 file changed, 3 deletions(-)
>
> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
> index 3c899cd4a0..9dd3738d44 100644
> --- a/xen/arch/arm/setup.c
> +++ b/xen/arch/arm/setup.c
> @@ -798,9 +798,6 @@ void __init start_xen(unsigned long boot_phys_offset,
>       percpu_init_areas();
>       set_processor_id(0); /* needed early, for smp_processor_id() */
>   
> -    set_current((struct vcpu *)0xfffff000); /* debug sanity */
> -    idle_vcpu[0] = current;
> -
>       setup_virtual_regions(NULL, NULL);
>       /* Initialize traps early allow us to get backtrace when an error 
> occurred */
>       init_traps();
--
Julien Grall

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