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Differential D48579

arm64: add inline functions for FEAT_WFxT instructions
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Authored by harry.moulton_arm.com on Tue, Jan 21, 3:21 PM.

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andrew
manu
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arm64
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rGe1c77d783206: arm64: add inline functions for FEAT_WFxT instructions
Summary

This adds inline functions for WFET/WFIT instructions introduced with
ARMv8.7 FEAT_WFxT. These instructions allow for regular WFE/WFI
instructions to be bound by a timeout. Once the value of CNTVCT_EL0
reaches, or exceeds, that of the timeout value, the WFE/WFI state will
be exited and the PE will continue.

These instructions are implemented as inline functions, with a write to
the corresponding system register acting as an alias for the two
instructions. Writing to these registers is only valid on ARMv8.7 and
above, therefore the use of these functions must be guarded by a feature
check.

Sponsored By: Arm Ltd
Signed-off-by: Harry Moulton <harry.moulton@arm.com>

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rG FreeBSD src repository
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Event Timeline

harry.moulton_arm.com created this revision.Tue, Jan 21, 3:21 PM
Herald added a reviewer: manu. · View Herald TranscriptTue, Jan 21, 3:21 PM
Herald added subscribers: emaste, imp. · View Herald Transcript
harry.moulton_arm.com requested review of this revision.Tue, Jan 21, 3:21 PM
harry.moulton_arm.com added a parent revision: D48578: arm64: add HWCAP for FEAT_WFxT.
harry.moulton_arm.com added a child revision: D48580: arm64: use FEAT_WFxT for DELAY() when available.
Harbormaster completed remote builds in B61867: Diff 149668.Tue, Jan 21, 3:21 PM
harry.moulton_arm.com added a parent revision: D48577: arm64: fix ID_AA64ISAR2_WFxT_IMPL value.Tue, Jan 21, 3:23 PM
andrew added inline comments.Tue, Jan 21, 3:46 PM
sys/arm64/include/cpufunc.h
169

Do you need the cast here? val is already a uint64_t

harry.moulton_arm.com updated this revision to Diff 149675.Tue, Jan 21, 5:40 PM

Cast to uint64_t not needed, removed.

Harbormaster completed remote builds in B61871: Diff 149675.Tue, Jan 21, 5:40 PM
andrew accepted this revision.Tue, Jan 21, 5:41 PM
This revision is now accepted and ready to land.Tue, Jan 21, 5:41 PM
Closed by commit rGe1c77d783206: arm64: add inline functions for FEAT_WFxT instructions (authored by harry.moulton_arm.com, committed by andrew). · Explain WhyThu, Jan 23, 5:27 PM
This revision was automatically updated to reflect the committed changes.
andrew added a commit: rGe1c77d783206: arm64: add inline functions for FEAT_WFxT instructions.

Revision Contents
Changeset List

PathSize
sys/
arm64/
include/
20 lines

Diff 149805

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sys/arm64/include/cpufunc.h

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