Re: [PATCH v2] sparc64: Add support for Application Data Integrity (ADI)

[David Miller]

From: Khalid Aziz <khalid.aziz@xxxxxxxxxx>
Date: Mon, 7 Mar 2016 14:27:09 -0700

> I agree with your point of view. PSTATE.mcde and TTE.mcd are set in
> response to request from userspace. If userspace asked for them to be
> set, they already know but it was the database guys that asked for
> these two functions and they are the primary customers for the ADI
> feature. I am not crazy about this idea since this extends the
> mprotect API even further but would you consider using the return
> value from mprotect to indicate if PSTATE.mcde or TTE.mcd were already
> set on the given address?

Well, that's the idea.

If the mprotect using MAP_ADI or whatever succeeds, then ADI is
enabled.

Users can thus also pass MAP_ADI as a flag to mmap() to get ADI
protection from the very beginning.