2014-02-27 19:15:35

by Arnd Bergmann

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Subject: Re: Fwd: [RFC][PATCH] staging: Fix build issues with new binder API

On Wednesday 26 February 2014, John Stultz wrote:
> The new 64bit binder API causes build issues on 32bit ARM
> due to the lack of 64bit __get_user_asm_* implementation.

It is impossible to implement this. Many have tried before.

> Until that implementation is done, remove the choice for
> 32bit ARM, automatically enabling the old 32bit binder
> protocol.
>
> This can be reverted once a 64bit __get_user_asm_*
> implementation is merged.

I think the best solution is to use __copy_from_user for
the 64-bit access. You can wrap it in a helper function
if you want to speed up the native-word-size case.

Arnd


2014-02-27 19:20:41

by John Stultz

[permalink] [raw]
Subject: Re: Fwd: [RFC][PATCH] staging: Fix build issues with new binder API

On 02/27/2014 11:15 AM, Arnd Bergmann wrote:
> On Wednesday 26 February 2014, John Stultz wrote:
>> The new 64bit binder API causes build issues on 32bit ARM
>> due to the lack of 64bit __get_user_asm_* implementation.
> It is impossible to implement this. Many have tried before.
>
>> Until that implementation is done, remove the choice for
>> 32bit ARM, automatically enabling the old 32bit binder
>> protocol.
>>
>> This can be reverted once a 64bit __get_user_asm_*
>> implementation is merged.
> I think the best solution is to use __copy_from_user for
> the 64-bit access. You can wrap it in a helper function
> if you want to speed up the native-word-size case.

Ah. Thanks for the context and the tip. Will try to get an appropriate
solution there then.

thanks
-john