Re: [PATCH] xen/arm: Init traps very early

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 28/05/14 14:33, Julien Grall wrote:
> The function init_traps setups the handler taken when Xen hits a BUG_ON/ASSERT.
>
> If an error happen before init_traps is called, we loose the backtrace.
>
> As the function doesn't require any specific setup, we can call it just
> after Xen has jumped in C code.
>
> Signed-off-by: Julien Grall <julien.grall@linaro.org>
> ---
>  xen/arch/arm/setup.c |    3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
> index b9ce7a9..5bf8686 100644
> --- a/xen/arch/arm/setup.c
> +++ b/xen/arch/arm/setup.c
> @@ -666,6 +666,7 @@ void __init start_xen(unsigned long boot_phys_offset,
>      struct domain *dom0;
>  
>      setup_cache();
> +    init_traps();

Having recently redone this in x86, it must be after
set_processor_id(0), set_current() for debug sanity, and after
percpu_init_areas() for future proofing.

~Andrew

>  
>      percpu_init_areas();
>      set_processor_id(0); /* needed early, for smp_processor_id() */
> @@ -709,8 +710,6 @@ void __init start_xen(unsigned long boot_phys_offset,
>      set_current((struct vcpu *)0xfffff000); /* debug sanity */
>      idle_vcpu[0] = current;
>  
> -    init_traps();
> -
>      setup_virt_paging();
>  
>      p2m_vmid_allocator_init();