Re: [PATCH v4 0/4] arm64: SPE ACPI enablement

From: Will Deacon
Date: Tue Jun 18 2019 - 12:47:16 EST

On Fri, Jun 14, 2019 at 08:09:06PM -0500, Jeremy Linton wrote:
> This patch series enables the Arm Statistical Profiling
> Extension (SPE) on ACPI platforms.
> This is possible because ACPI 6.3 uses a previously
> reserved field in the MADT to store the SPE interrupt
> number, similarly to how the normal PMU is described.
> If a consistent valid interrupt exists across all the
> cores in the system, a platform device is registered.
> That then triggers the SPE module, which runs as normal.
> We also add the ability to parse the PPTT for IDENTICAL
> cores. We then use this to sanity check the single SPE
> device we create. This creates a bit of a problem with
> respect to the specification though. The specification
> says that its legal for multiple tree's to exist in the
> PPTT. We handle this fine, but what happens in the
> case of multiple tree's is that the lack of a common
> node with IDENTICAL set forces us to assume that there
> are multiple non-IDENTICAL cores in the machine.
> v3->v4: Rebase to 5.2.
> Minor formatting, patch rearrangement.
> Add missing `inline` in static header definition.
> Drop ARM_SPE_ACPI and just use ARM_SPE_PMU.

I'm happy to take this via the arm64 perf tree for 5.3, but I'll need
Acks from Raphael on the first two patches and an Ack from Lorenzo on
patch 3.