Re: [Qemu-devel] [PATCH v2 01/12] ARM: Export cpu_env

[Peter Maydell <peter.maydell@linaro.org>]

On 30 April 2013 13:00, Andreas Färber <afaerber@suse.de> wrote:
> Am 30.04.2013 13:54, schrieb Alexander Graf:
>> Am 30.04.2013 um 13:42 schrieb Andreas Färber <afaerber@suse.de>:
>>
>>> Am 30.04.2013 08:36, schrieb John Rigby:
>>>> From: Alexander Graf <agraf@suse.de>
>>>> diff --git a/target-arm/translate.c b/target-arm/translate.c
>>>> index 675773a..36537bd 100644
>>>> --- a/target-arm/translate.c
>>>> +++ b/target-arm/translate.c
>>>> @@ -59,7 +59,7 @@ static uint32_t gen_opc_condexec_bits[OPC_BUF_SIZE];
>>>> #define DISAS_WFI 4
>>>> #define DISAS_SWI 5
>>>>
>>>> -static TCGv_ptr cpu_env;
>>>> +TCGv_ptr cpu_env;
>>>> /* We reuse the same 64-bit temporaries for efficiency.  */
>>>> static TCGv_i64 cpu_V0, cpu_V1, cpu_M0;
>>>> static TCGv_i32 cpu_R[16];
>>>> diff --git a/target-arm/translate.h b/target-arm/translate.h
>>>> index e727bc6..8ba1433 100644
>>>> --- a/target-arm/translate.h
>>>> +++ b/target-arm/translate.h
>>>> @@ -24,4 +24,6 @@ typedef struct DisasContext {
>>>>     int vec_stride;
>>>> } DisasContext;
>>>>
>>>> +extern TCGv_ptr cpu_env;
>>>> +
>>>> #endif /* TARGET_ARM_TRANSLATE_H */
>>>
>>> Alex, have you checked whether the variable can be placed in qom/cpu.c
>>> instead once for all targets? I'd hope that would be possible with an
>>> appropriate typedef (since target_long size etc. are unknown there).
>>
>> I would prefer to keep the translation context separate from the execution context.
>
> Not sure if you understood my point? Exposing cpu_env from target-arm
> would seem to torpedo our efforts to link target-arm and, e.g.,
> target-microblaze together, since they all have cpu_env. I don't really
> care if it's qom/cpu.c or tcg/shared.c or renaming to arm_cpu_env. :)

So we could deal with this by:
 translate-a64.c has its own 'static TCGv_ptr cpu_env;'
 translate.c:arm_translate_init() passes cpu_env to
   a64_translate_init()
 translate-a64.c:a64_translate_init() stashes the value it
   gets passed in its own cpu_env static.

That avoids having it be a non-static global and doesn't require us
to rename every usage of cpu_env in translate.c either.

Any objections?

thanks
-- PMM