Re: [PATCH 5/5] target/arm: Correctly implement Feat_DoubleLock

[Richard Henderson <richard.henderson@linaro.org>]

On 7/1/22 01:11, Peter Maydell wrote:
> +static inline bool isar_feature_any_doublelock(const ARMISARegisters *id)
> +{
> +    /*
> +     * We can't just OR together the aa32 and aa64 checks, because
> +     * if there is no AArch64 support the aa64 function will default
> +     * to returning true for a zero id_aa64dfr0.
> +     * We use "is id_aa64pfr0 non-zero" as a proxy for "do we have
> +     * the AArch64 ID register values in id", because it's always the
> +     * case that ID_AA64PFR0_EL1.EL0 at least will be non-zero.
> +     */
> +    if (id->id_aa64pfr0) {
> +        return isar_feature_aa64_doublelock(id);
> +    }
> +    return isar_feature_aa32_doublelock(id);
> +}

If you're going to rely on this, you need to clear this register for -cpu aarch64=off. 
It's probably easier to drop this function...

> +static void osdlr_write(CPUARMState *env, const ARMCPRegInfo *ri,
> +                        uint64_t value)
> +{
> +    /*
> +     * Only defined bit is bit 0 (DLK); if Feat_DoubleLock is not
> +     * implemented this is RAZ/WI.
> +     */
> +    if (cpu_isar_feature(any_doublelock, env_archcpu(env))) {

... and use

     if (arm_feature(env, ARM_FEATURE_AARCH64)
         ? cpu_isar_feature(aa64_doublelock, cpu)
         : cpu_isar_feature(aa32_doublelock, cpu)) {

since it's just used once.


r~