Re: [Xen-devel] [PATCH 3/4] arm: traps: handle unknown exceptions in check_conditional_instr()

[Julien Grall <julien.grall@xxxxxxx>]

Hi,

On 07/28/2017 08:43 PM, Volodymyr Babchuk wrote:
> According to ARM architecture reference manual, exception with
version + paragraph

> unknown reason (HSR.EC == 0) have no valid bits in HSR
> (apart from HSR.EC), so we can't check if that was caused by
> conditional instruction. We need  assume that it is uncoditional.
unconditional

> Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>
> ---
>   xen/arch/arm/traps.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
> index c07999b..eae2212 100644
> --- a/xen/arch/arm/traps.c
> +++ b/xen/arch/arm/traps.c
> @@ -1717,7 +1717,7 @@ static int check_conditional_instr(struct cpu_user_regs 
> *regs,
>       int cond;
>   
>       /* Unconditional Exception classes */
> -    if ( hsr.ec >= 0x10 )
> +    if ( hsr.ec == HSR_EC_UNKNOWN || hsr.ec >= 0x10 )
>           return 1;
>   
>       /* Check for valid condition in hsr */
--
Julien Grall

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