Re: [PATCH RFC 8/8] xen/arm: Some early trap logging

[Julien Grall <julien.grall@linaro.org>]

On 09/10/2013 03:18 PM, Ian Campbell wrote:
> Not for really for application, might be useful to someone?

I think it could be useful for early debugging on new platform or until
init_traps initialized the correct handlers.

Can you update this patch with more information about the trap (reset,
undefined, ...)?

> 
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> ---
>  xen/arch/arm/arm32/head.S |   15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S
> index 79e95b6..06d53ad 100644
> --- a/xen/arch/arm/arm32/head.S
> +++ b/xen/arch/arm/arm32/head.S
> @@ -366,6 +366,9 @@ paging:
>          bne   1b
>  
>  launch:
> +        adr   r0, early_trap_vector
> +        mcr   CP32(r0, VBAR_EL2)
> +        
>          ldr   r0, =init_stack        /* Find the boot-time stack */
>          ldr   sp, [r0]
>          add   sp, #STACK_SIZE        /* (which grows down from the top). */
> @@ -376,12 +379,24 @@ launch:
>          beq   start_xen              /* and disappear into the land of C */
>          b     start_secondary        /* (to the appropriate entry point) */
>  
> +trap_early:
> +        PRINT("\r\nEARLY TRAP\r\n")
>  /* Fail-stop
>   * r0: string explaining why */
>  fail:   PRINT("- Boot failed -\r\n")
>  1:      wfe
>          b     1b
>  
> +        .align 5
> +early_trap_vector:
> +        .word 0                         /* 0x00 - Reset */
> +        b trap_early                    /* 0x04 - Undefined Instruction */
> +        b trap_early                    /* 0x08 - Supervisor Call */
> +        b trap_early                    /* 0x0c - Prefetch Abort */
> +        b trap_early                    /* 0x10 - Data Abort */
> +        b trap_early                    /* 0x14 - Hypervisor */
> +        b trap_early                    /* 0x18 - IRQ */
> +        b trap_early                    /* 0x1c - FIQ */
>  
>  #ifdef EARLY_PRINTK
>  /* Bring up the UART.
> 


-- 
Julien Grall