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Differential D33079

Per-thread stack canary on arm64
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Authored by andrew on Nov 22 2021, 4:38 PM.

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rGb5346307ed34: Per-thread stack canary on arm64
rGae92ace05fd4: Per-thread stack canary on arm64

Summary

With the update to llvm 13 we are able to tell the compiler it can find
the SSP canary relative to the register that holds the userspace stack
pointer. As this is unused in most of the kernel it can be used here
to point to a per-thread SSP canary.

As the kernel could be built with an old toolchain, e.g. when upgrading
from 13, add a warning that the options was enabled but the compiler
doesn't support it to both the build and kernel boot.

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rG FreeBSD src repository

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Event Timeline

andrew created this revision.Nov 22 2021, 4:38 PM

Herald added a reviewer: manu. · View Herald TranscriptNov 22 2021, 4:38 PM

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

andrew requested review of this revision.Nov 22 2021, 4:38 PM

Harbormaster completed remote builds in B42918: Diff 98839.Nov 22 2021, 4:38 PM

emaste added inline comments.Nov 22 2021, 4:43 PM

sys/conf/Makefile.arm64
35	`perthread-ssp` in `COMPILER_FEATURES` perhaps?

andrew added inline comments.Nov 22 2021, 4:56 PM

sys/conf/Makefile.arm64
35	We could although it's not something userspace could use as `sp_el0` is only available to the kernel & hypervisor.

emaste added inline comments.Nov 26 2021, 1:12 AM

sys/conf/Makefile.arm64
35	Yeah, I guess this is fine

This revision was not accepted when it landed; it landed in state Needs Review.Nov 26 2021, 2:51 PM

Closed by commit rGae92ace05fd4: Per-thread stack canary on arm64 (authored by andrew). · Explain Why

This revision was automatically updated to reflect the committed changes.

andrew added a commit: rGae92ace05fd4: Per-thread stack canary on arm64.

andrew added a commit: rGb5346307ed34: Per-thread stack canary on arm64.Dec 20 2021, 2:02 PM

Revision Contents
Changeset List

Path

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sys/

arm64/

arm64/

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1 line

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4 lines

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conf/

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include/

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conf/

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Diff 99054

sys/arm64/arm64/exception.S

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sys/arm64/arm64/genassym.c

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sys/arm64/arm64/locore.S

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sys/arm64/arm64/machdep.c

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sys/arm64/arm64/pmap.c

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sys/arm64/arm64/vm_machdep.c

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sys/arm64/conf/std.arm64

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sys/arm64/include/proc.h

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sys/conf/Makefile.arm64

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sys/conf/options.arm64

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