kinst/arm64: Fix return values from kinst_invop()
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Authored by markj on Wed, May 13, 4:04 PM.

Details

Reviewers

christos
andrew

Group Reviewers

DTrace
arm64

Commits

rG25bb939c7871: kinst/arm64: Fix return values from kinst_invop()
rGd6f0e671d079: kinst/arm64: Fix return values from kinst_invop()

Summary

After commit 853cd8723494 it became invalid for kinst_invop() to return
0: dtrace_invop_start() would convert this to a sentinel value
indicating that it did not consume the breakpoint, and so we'd just
call kdb_trap() to handle it.

Change kinst_invop() to return NOP_INSTR after handling a matching
breakpoint. NOP_INSTR is handled by advancing the ELR, so we have to
compensate by subtracting INSTR_SIZE before returning.

Fixes: 853cd8723494 ("arm64: Clean up usage of the dtrace invop handler")

Diff Detail

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rG FreeBSD src repository

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Event Timeline

markj created this revision.Wed, May 13, 4:04 PM

Herald added a reviewer: andrew. · View Herald TranscriptWed, May 13, 4:04 PM

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

markj requested review of this revision.Wed, May 13, 4:04 PM

Harbormaster completed remote builds in B73075: Diff 177785.Wed, May 13, 4:04 PM

markj added a child revision: D56988: kinst/arm64: Handle an additional PC-relative instruction.Wed, May 13, 4:04 PM

christos added inline comments.Thu, May 14, 2:25 PM

sys/cddl/dev/kinst/aarch64/kinst_isa.c
233–234	I think it'd be good to include the explanation from the commit message here as well. After a while it might not be obvious what we meant here.