arm64: Add the SVE registers to the signal frame
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Authored by andrew on Jan 4 2024, 12:32 PM.

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Reviewers

kib
markj
manu

Group Reviewers

arm64

Commits

rG7588c7024ed9: arm64: Add the SVE registers to the signal frame
rGe45132e97803: arm64: Add the SVE registers to the signal frame

Summary

Use the new extended register support in the arm64 signal frame to
handle the SVE registers.

As these registers alias the VFP registers we use the floating point
register values to restore the lower bits of the SVE registers. This
is to support software that doesn't understand SVE to continue working.

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Repository

rG FreeBSD src repository

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Buildable 58162
Build 55050: arc lint + arc unit

Event Timeline

andrew created this revision.Jan 4 2024, 12:32 PM

Herald added a reviewer: manu. · View Herald TranscriptJan 4 2024, 12:32 PM

Herald added subscribers: emaste, imp. · View Herald Transcript

andrew requested review of this revision.Jan 4 2024, 12:32 PM

Harbormaster completed remote builds in B55237: Diff 132254.Jan 4 2024, 12:32 PM

andrew added a parent revision: D43306: arm64: Initial SVE support.Jan 4 2024, 12:32 PM

andrew added a child revision: D43308: arm64: Add an SVE sysarch.

I have the same question here I did about the other change to sigreturn: why no changes to setcontext and how does this interact with them?

andrew mentioned this in D43302: arm64: Support passing more registers to signals.Mar 6 2024, 5:06 PM

I don't think we need to store the SCE registers in getcontextx. It's a function call that doesn't take an SVE register as an argument so the ABI doesn't require the upper bits of SVE registers to be preserved. We could restore the SVE registers in setcontextx if they are in the list of registers.