On Wed, 8 Dec 2021 14:11:19 -0600, Rob Herring wrote:

Another version of arm64 userspace counter access support. No changes from
the last version except rebasing and rewriting a commit message.

The arm64 support departs from the x86 implementation by requiring the user
to explicitly request user access (via attr.config1) and only enables access
for task bound events. Since usage is explicitly requested, access is
enabled at perf_event_open() rather than on mmap() as that greatly
simplifies the implementation. Rather than trying to lock down the access
as the x86 implementation has been doing, we can start with only a limited
use case enabled and later expand it if needed.

[...]

Applied to will (for-next/perf-user-counter-access), thanks!

[1/5] x86: perf: Move RDPMC event flag to a common definition
      https://git.kernel.org/arm64/c/369461ce8fb6
[2/5] perf: Add a counter for number of user access events in context
      https://git.kernel.org/arm64/c/82ff0c022d19
[3/5] arm64: perf: Add userspace counter access disable switch
      https://git.kernel.org/arm64/c/e2012600810c
[4/5] arm64: perf: Enable PMU counter userspace access for perf event
      https://git.kernel.org/arm64/c/83a7a4d643d3
[5/5] Documentation: arm64: Document PMU counters access from userspace
      https://git.kernel.org/arm64/c/aa1005d15d2a

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev

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