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Differential D35234

Support LSE atomics in the arm64 casue* functions
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Authored by andrew on May 17 2022, 1:56 PM.
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emaste
imp

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Reviewers
markj
kib
manu
Group Reviewers
arm64
Commits
rG20d21e435145: Support LSE atomics in the arm64 casue* functions
rG88ac318759f2: Support LSE atomics in the arm64 casue* functions
Summary

As with atomic(9) use the ARMv8.1 Large System Extension atomic
instructions to implement the userspace compare and swap functions.

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Repository
rS FreeBSD src repository - subversion
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No Test Coverage
Build Status
Buildable 45607
Build 42495: arc lint + arc unit

Event Timeline

andrew created this revision.May 17 2022, 1:56 PM
Herald added a reviewer: manu. · View Herald TranscriptMay 17 2022, 1:56 PM
Herald added subscribers: emaste, imp. · View Herald Transcript
andrew requested review of this revision.May 17 2022, 1:56 PM
Harbormaster completed remote builds in B45607: Diff 106108.May 17 2022, 1:56 PM
andrew added a reviewer: arm64.May 17 2022, 2:01 PM
kib accepted this revision.May 17 2022, 11:47 PM

I believe that the patch itself if fine.

But I noted a thing with casueword(32) and its use in kern_umtx.c. It seems that kern_umtx.c assumes that the function has sequential-constistent fence semantic. Note that both lock acquire and release just return success if casueword32 succeeded, in do_lock_normal() and do_unlock_normal(). The full fence semantic is provided on x86, but I suspect all ll/sc arches are affected.

This revision is now accepted and ready to land.May 17 2022, 11:47 PM
Closed by commit rG88ac318759f2: Support LSE atomics in the arm64 casue* functions (authored by andrew). · Explain WhyMay 19 2022, 10:33 AM
This revision was automatically updated to reflect the committed changes.
andrew added a commit: rG88ac318759f2: Support LSE atomics in the arm64 casue* functions.
andrew added a commit: rG20d21e435145: Support LSE atomics in the arm64 casue* functions.Jun 7 2022, 2:24 PM

Revision Contents
Changeset List

PathSize
sys/
arm64/
arm64/
52 lines
58 lines
conf/
1 line

Diff 106108

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sys/arm64/arm64/support.S

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sys/arm64/arm64/support_ifunc.c

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sys/conf/files.arm64

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