Re: [PATCH v8 3/3] x86, mce: Add __mcsafe_copy()

[Tony Luck]

On Mon, Jan 11, 2016 at 2:44 AM, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
> So such a synthetic CPUID bit would definitely be useful.
>
> Also, knowing whether a memcpy function is recoverable or not, should not be
> delegated to callers: there should be the regular memcpy APIs, plus new APIs that
> do everything they can to provide recoverable memory copies. Whether it's achieved
> via flag checking, a function pointer or code patching is an implementation detail
> that's not visible to drivers making use of the new facility.
>
> I'd go for the simplest, most robust solution initially, also perhaps with boot
> time messages to make sure users know which variant is used and now.

Are there some examples of synthetic CPUID bits?  I grepped around and
found a handful of places making ad hoc decisions based on sub-strings of
x86_model_id[] ... but didn't find any systematic approach.

-Tony