Re: [Qemu-devel] [PATCH v1 16/22] target-arm: A64: Forbid ERET to unimplemented ELs

[Peter Crosthwaite]

On Tue, May 6, 2014 at 4:08 PM, Edgar E. Iglesias
<address@hidden> wrote:
> From: "Edgar E. Iglesias" <address@hidden>
>
> Check for EL2 support before returning to it.
>
> Signed-off-by: Edgar E. Iglesias <address@hidden>

Reviewed-by: Peter Crosthwaite <address@hidden>

> ---
>  target-arm/op_helper.c | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/target-arm/op_helper.c b/target-arm/op_helper.c
> index 770c776..f1ae05e 100644
> --- a/target-arm/op_helper.c
> +++ b/target-arm/op_helper.c
> @@ -411,12 +411,10 @@ void HELPER(exception_return)(CPUARMState *env)
>          env->regs[15] = env->elr_el[ELR_EL_IDX(1)] & ~0x1;
>      } else {
>          new_el = extract32(spsr, 2, 2);
> -        if (new_el > cur_el) {
> +        if (new_el > cur_el
> +            || (new_el == 2 && !arm_feature(env, ARM_FEATURE_EL2))) {
>              /* Disallow returns to higher ELs than the current one.  */
> -            goto illegal_return;
> -        }
> -        if (new_el > 1) {
> -            /* Return to unimplemented EL */
> +            /* Disallow returns to unimplemented ELs.  */
>              goto illegal_return;
>          }
>          if (extract32(spsr, 1, 1)) {
> --
> 1.8.3.2
>
>