Re: [Xen-devel] [PATCH v2 3/4] arm: traps: handle unknown exceptions in check_conditional_instr()

[Julien Grall <julien.grall@xxxxxxx>]

On 09/08/2017 20:44, Volodymyr Babchuk wrote:
> According to ARM architecture reference manual (ARM DDI 0487A.k page D7-1938,
Please quote a more recent ARM ARM. In general, please use the latest 
ARM ARM when sending code specific to the architecture.
Assuming this will be fixed in the next revision:

Acked-by: Julien Grall <julien.grall@xxxxxxx>

Cheers,


> ARM DDI 0406C.c page B3-1426), exception with 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 unconditional.
>
> Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>
> ---
>
> - Added reference to the ARM manuals
>
> ---
>  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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