Re: [Qemu-devel] [PATCH target-arm v3 8/8] target-arm: Call pmccntr_sync() when swapping ELs

[Peter Crosthwaite]

On Mon, Aug 18, 2014 at 6:32 PM, Peter Maydell <address@hidden> wrote:
> On 18 August 2014 09:16, Peter Crosthwaite <address@hidden> wrote:
>> Call the pmccntr_sync() when the EL changes. All Runtime changes
>> of EL are done as a pstate_write so we can catch these EL-change side
>> effects here.
>
> Hmm. This probably clashes badly with Alex's cleanup of how we
> handle pstate writes... I'm not sure I really want more side
> effects in pstate_write(), either; the ones we have in cpsr_write()
> are pretty annoying (makes migration load awkward).
>

Well what exactly can we do then? Do we need another fn between el
change logic and pstate_write where we can dump el change side
effects?

At the end of the day, changing EL does have side effects so we need a
common place for this stuff.

Regards,
Peter

>> Signed-off-by: Peter Crosthwaite <address@hidden>
>> ---
>>
>>  target-arm/cpu.h | 12 ++++++++++++
>>  1 file changed, 12 insertions(+)
>>
>> diff --git a/target-arm/cpu.h b/target-arm/cpu.h
>> index 5bc2afe..2533fc0 100644
>> --- a/target-arm/cpu.h
>> +++ b/target-arm/cpu.h
>> @@ -503,12 +503,24 @@ static inline uint32_t pstate_read(CPUARMState *env)
>>
>>  static inline void pstate_write(CPUARMState *env, uint32_t val)
>>  {
>> +#ifndef CONFIG_USER_ONLY
>> +    bool pmccntr_need_sync = (env->pstate ^ val) & PSTATE_M;
>> +
>> +    if (pmccntr_need_sync) {
>> +        pmccntr_sync(env);
>> +    }
>> +#endif
>>      env->ZF = (~val) & PSTATE_Z;
>>      env->NF = val;
>>      env->CF = (val >> 29) & 1;
>>      env->VF = (val << 3) & 0x80000000;
>>      env->daif = val & PSTATE_DAIF;
>>      env->pstate = val & ~CACHED_PSTATE_BITS;
>> +#ifndef CONFIG_USER_ONLY
>> +    if (pmccntr_need_sync) {
>> +        pmccntr_sync(env);
>> +    }
>> +#endif
>>  }
>>
>>  /* Return the current CPSR value.  */
>> --
>> 2.0.1.1.gfbfc394
>
> thanks
> -- PMM
>