arm64 hwpmc: Support restricting counters to user or kernel mode.
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Authored by jhb on Mar 11 2022, 1:18 AM.

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Reviewers

markj
manu
andrew
emaste
gnn

Commits

rGf5858d5551b4: arm64 hwpmc: Support restricting counters to user or kernel mode.
rG6bb7ba4aa180: arm64 hwpmc: Support restricting counters to user or kernel mode.

Summary

Support the "usr" and "os" qualifiers on arm64 events to restrict
event counting to either usermode or the kernel, respectively.
If neither qualifier is given, events are counted in both.

Sponsored by: University of Cambridge, Google, Inc.

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rG FreeBSD src repository

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Event Timeline

jhb created this revision.Mar 11 2022, 1:18 AM

Herald added a subscriber: imp. · View Herald TranscriptMar 11 2022, 1:18 AM

jhb requested review of this revision.Mar 11 2022, 1:18 AM

jhb added a parent revision: D34526: aarch64: Add constants for fields in the PMEVTYPERn_EL0 event registers..

Harbormaster completed remote builds in B44741: Diff 103749.Mar 11 2022, 1:18 AM

emaste accepted this revision.Mar 11 2022, 3:42 AM

emaste added inline comments.

sys/dev/hwpmc/hwpmc_arm64.c
191	using a switch here to "handle" `PMC_CAP_SYSTEM \| PMC_CAP_USER` is clever but IMO might be worth a comment

This revision is now accepted and ready to land.Mar 11 2022, 3:42 AM

jhb added inline comments.Mar 11 2022, 5:13 PM

sys/dev/hwpmc/hwpmc_arm64.c
191	Ok, I will add a default case with a comment.

emaste added inline comments.Mar 11 2022, 5:24 PM

sys/dev/hwpmc/hwpmc_arm64.c
191	Sounds good - at first I didn't read the description in the commit message and it looked strange to me. I figured it out after looking at the Arm ARM.