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Differential D42241

amd64: Zero-fill AP PCPU pages
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Authored by markj on Oct 16 2023, 10:51 PM.
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kib
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rGe4d86dda3413: amd64: Zero-fill AP PCPU pages
rG4533fa42ad91: amd64: Zero-fill AP PCPU pages
rGa37e484d0497: amd64: Zero-fill AP PCPU pages
Summary

At least KMSAN relies on zero-initialization of AP PCPU regions, see
commit 4b136ef259ce ("amd64: Set GS.base before calling init_secondary() on APs").
Prior to commit af1c6d3f3013 these were allocated with allocpages() in
the amd64 pmap, which always returns zero-initialized memory.

Fixes: af1c6d3f3013 ("amd64: do not leak pcpu pages")
MFC after: 3 days

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rG FreeBSD src repository
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Event Timeline

markj created this revision.Oct 16 2023, 10:51 PM
Herald added a subscriber: imp. · View Herald TranscriptOct 16 2023, 10:51 PM
markj requested review of this revision.Oct 16 2023, 10:51 PM
Harbormaster completed remote builds in B54019: Diff 128871.Oct 16 2023, 10:51 PM
kib accepted this revision.Oct 17 2023, 9:06 AM
kib added inline comments.
sys/amd64/amd64/mp_machdep.c
297

Why do you need a local var?

This revision is now accepted and ready to land.Oct 17 2023, 9:06 AM
markj added inline comments.Oct 17 2023, 1:04 PM
sys/amd64/amd64/mp_machdep.c
297

I just disliked the duplication.

Closed by commit rGa37e484d0497: amd64: Zero-fill AP PCPU pages (authored by markj). · Explain WhyOct 17 2023, 1:38 PM
This revision was automatically updated to reflect the committed changes.
markj added a commit: rGa37e484d0497: amd64: Zero-fill AP PCPU pages.
markj added a commit: rG4533fa42ad91: amd64: Zero-fill AP PCPU pages.Oct 20 2023, 4:02 PM
markj added a commit: rGe4d86dda3413: amd64: Zero-fill AP PCPU pages.Oct 22 2023, 3:06 PM

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sys/
amd64/
amd64/
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sys/amd64/amd64/mp_machdep.c

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