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Differential D22133

ARM64: Treat alignment faults as bus errors
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Authored by jhibbits on Oct 23 2019, 7:10 PM.
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andrew
emaste
imp
stevek

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manu
andrew
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ARM
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rS354182: ARM64: Treat alignment faults as bus errors
Summary

ARM64 currently treats all data abort exceptions as page faults. This
can cause infinite loops on non-page fault faults, such as alignment faults.

Since kernel-side alignment faults should be avoided, this adds support directly
to the el0 fault handler, instead of the data_abort() handler.

Test Plan

Tested on rpi3, with a misaligned ldm test.

Diff Detail

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rS FreeBSD src repository - subversion
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Event Timeline

jhibbits created this revision.Oct 23 2019, 7:10 PM
Herald added a reviewer: manu. · View Herald TranscriptOct 23 2019, 7:10 PM
Herald added subscribers: emaste, andrew, imp. · View Herald Transcript
Harbormaster completed remote builds in B27176: Diff 63602.Oct 23 2019, 7:10 PM
andrew added a comment.Oct 24 2019, 6:16 PM

I've been thinking we should use a table of function pointers similar to how 32 bit arm does it. There are a few other cases that shouldn't be handled by data_abort.

sys/arm64/arm64/trap.c
418 ↗(On Diff #63602)

I thing you want ISS_DATA_DFSC_MASK here.

jhibbits marked an inline comment as done.Oct 24 2019, 6:30 PM
jhibbits added inline comments.
sys/arm64/arm64/trap.c
418 ↗(On Diff #63602)

You're right, that makes more sense.

jhibbits updated this revision to Diff 63645.Oct 24 2019, 6:39 PM
jhibbits marked an inline comment as done.

Address @andrew's feedback. Use the right sub-mask to get the DFSC bits.

Harbormaster completed remote builds in B27206: Diff 63645.Oct 24 2019, 6:39 PM
andrew added a comment.Oct 28 2019, 12:04 PM

Can you rebase on top of D22170?

jhibbits updated this revision to Diff 63728.Oct 28 2019, 5:28 PM

Rebase on top of D22170

Harbormaster completed remote builds in B27243: Diff 63728.Oct 28 2019, 5:28 PM
andrew accepted this revision.Oct 30 2019, 10:43 AM
This revision is now accepted and ready to land.Oct 30 2019, 10:43 AM
Closed by commit rS354182: ARM64: Treat alignment faults as bus errors (authored by jhibbits). · Explain WhyOct 30 2019, 3:30 PM
This revision was automatically updated to reflect the committed changes.
jhibbits added a commit: rS354182: ARM64: Treat alignment faults as bus errors.

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head/
sys/
arm64/
arm64/
13 lines

Diff 63798

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head/sys/arm64/arm64/trap.c

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