> On Jun 7, 2019, at 1:49 AM, Ard Biesheuvel <ard.biesheu...@linaro.org> wrote:
>
>> On Fri, 7 Jun 2019 at 10:29, Peter Zijlstra <pet...@infradead.org> wrote:
>>
>> On Thu, Jun 06, 2019 at 10:44:23PM +0000, Nadav Amit wrote:
>>>> + * Usage example:
>>>> + *
>>>> + * # Start with the following functions (with identical prototypes):
>>>> + * int func_a(int arg1, int arg2);
>>>> + * int func_b(int arg1, int arg2);
>>>> + *
>>>> + * # Define a 'my_key' reference, associated with func_a() by default
>>>> + * DEFINE_STATIC_CALL(my_key, func_a);
>>>> + *
>>>> + * # Call func_a()
>>>> + * static_call(my_key, arg1, arg2);
>>>> + *
>>>> + * # Update 'my_key' to point to func_b()
>>>> + * static_call_update(my_key, func_b);
>>>> + *
>>>> + * # Call func_b()
>>>> + * static_call(my_key, arg1, arg2);
>>>
>>> I think that this calling interface is not very intuitive.
>>
>> Yeah, it is somewhat unfortunate..
>>
>
> Another thing I brought up at the time is that it would be useful to
> have the ability to 'reset' a static call to its default target. E.g.,
> for crypto modules that implement an accelerated version of a library
> interface, removing the module should revert those call sites back to
> the original target, without putting a disproportionate burden on the
> module itself to implement the logic to support this.
I was thinking this could be a layer on top. We could have a way to register a
static call with the module core so that, when a GPL module with an appropriate
symbol is loaded, the static call gets replaced.
KVM could use this too. Or we could just require KVM to be built in some day.
