Hi James,

On Tue, Jun 26, 2018 at 06:00:56PM +0100, James Morse wrote:

The aim of this series is to wire arm64's SDEI into APEI.

On arm64 we have three APEI notifications that are NMI-like, and
in the unlikely event that all three are supported by a platform,
they can interrupt each other.
The GHES driver shouldn't have to deal with this, so this series aims
to make it re-entrant.

To do that, we refactor the estatus queue to allow multiple notifications
to use it, then convert NOTIFY_SEA to always be described as NMI-like,
and to use the estatus queue.

From here we push the locking and fixmap choices out to the notification
functions, and remove the use of per-ghes estatus and flags. This removes
the in_nmi() 'timebomb' in ghes_copy_tofrom_phys().

Things get sticky when an NMI notification needs to know how big the
CPER records might be, before reading it. This series splits
ghes_estatus_read() to let us peek at the buffer. A side effect of this
is the 20byte header will get read twice. (how does it work today? it
reads the records into a per-ghes worst-case sized buffer, allocates
the correct size and copies the records. in_nmi() use of this per-ghes
buffer needs eliminating).

One alternative was to trust firmware's 'max raw data length' and use
that to allocate 'enough' memory. We don't use this value today, so its
probably wrong on some sytem somewhere.

Since v4 patches 5,8-15 are new, otherwise changes are noted in the patch.

The little bits touching arch/arm64/ all look fine to me here, but it looks
like other patches need review separately and ultimately I suspect you're
going to route it via some other tree.

Let me know if you need me to help with anything.

Will