Date: Mon, 07 Mar 2016 14:16:00 -0500 (EST)
Message-Id: <20160307.141600.1873883635480850431.davem@davemloft.net>
To: khalid.aziz@oracle.com
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Subject: Re: [PATCH v2] sparc64: Add support for Application Data Integrity
 (ADI)
From: David Miller <davem@davemloft.net>
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	<56DDC776.3040003@oracle.com>
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From: Khalid Aziz <khalid.aziz@oracle.com>
Date: Mon, 7 Mar 2016 11:24:54 -0700

> Tags can be cleared by user by setting tag to 0. Tags are
> automatically cleared by the hardware when the mapping for a virtual
> address is removed from TSB (which is why swappable pages are a
> problem), so kernel does not have to do it as part of clean up.

You might be able to crib some bits for the Tag in the swp_entry_t, it's
64-bit and you can therefore steal bits from the offset field.

That way you'll have the ADI tag in the page tables, ready to re-install
at swapin time.