Re: [Qemu-devel] [PATCH v2 04/23] target-arm: preserve RAO/WI bits of ARMv7 SCTLR

[Sergey Fedorov <serge.fdrv@gmail.com>]

On 13.05.2014 20:15, Fabian Aggeler wrote:
> From: Svetlana Fedoseeva <s.fedoseeva@samsung.com>
>
> Signed-off-by: Svetlana Fedoseeva <s.fedoseeva@samsung.com>
> Signed-off-by: Sergey Fedorov <s.fedorov@samsung.com>
> Signed-off-by: Fabian Aggeler <aggelerf@ethz.ch>
> ---
>  target-arm/helper.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/target-arm/helper.c b/target-arm/helper.c
> index 9c3269f..2b57ad9 100644
> --- a/target-arm/helper.c
> +++ b/target-arm/helper.c
> @@ -2083,6 +2083,11 @@ static void sctlr_write(CPUARMState *env, const ARMCPRegInfo *ri,
>  {
>      ARMCPU *cpu = arm_env_get_cpu(env);
>  
> +    if (arm_feature(env, ARM_FEATURE_V7)) {
> +        value |= SCTLR_XP | SCTLR_U | SCTLR_nTWE | SCTLR_nTWI | SCTLR_L
> +                | SCTLR_CP15BEN | SCTLR_P; /* These bits are RAO/WI */

Actually, some of these bits are RAO/WI since v6. Also, there are some
RAZ/WI bits varying over architecture variants. There is some overview
at ARM ARM v7-AP section L.7.4. Maybe it is worth to fix more precisely
over supported architecture variants? By the way, this patch could be
separated from security extensions support patch set.

Thanks,
Sergey.

> +    }
> +
>      env->cp15.c1_sys = value;
>      /* ??? Lots of these bits are not implemented.  */
>      /* This may enable/disable the MMU, so do a TLB flush.  */