arm64: Reduce the kernel executable pages
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Authored by andrew on May 2 2024, 4:10 PM.

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emaste

imp

Details

Reviewers

manu
kib
markj
alc

Group Reviewers

arm64

Summary

When creating the kernel page tables we create them all executable to
allow the kernel to boot.

We can reduce the number of 2 blocks or l3 pages created as executable
by looking where the end of the .text section is and only marking
memory up to this as executable (rounded up to the block/page size).

Diff Detail

Repository

rG FreeBSD src repository

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Unit

Tests Skipped

Build Status

Buildable 57545
Build 54433: arc lint + arc unit

Event Timeline

andrew created this revision.May 2 2024, 4:10 PM

Herald added a reviewer: manu. · View Herald TranscriptMay 2 2024, 4:10 PM

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

andrew requested review of this revision.May 2 2024, 4:10 PM

Harbormaster completed remote builds in B57545: Diff 138022.May 2 2024, 4:10 PM

andrew added a parent revision: D45062: arm64: Use tables to find early page tables.May 2 2024, 4:10 PM

andrew added a child revision: D45064: arm64: Create an L3 table to limit permissions.

I assume that's supposed to be "l2 blocks" in the comment message?

And I guess it's really marking memory beyond this (rounded up end of .text) as non-executable

andrew added reviewers: kib, markj, alc.Jun 6 2024, 2:44 PM

Revision Contents
Changeset List

Path

Size

sys/

arm64/

locore.S

18 lines

Diff 138022

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arm64: Reduce the kernel executable pagesNeeds ReviewPublicActions