sys/arm64: fix COMPAT_FREEBSD32 __syscall()
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Authored by fuz on Tue, Oct 21, 10:18 PM.

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Reviewers

markj
cognet
andrew
jrtc27
manu
emaste

Commits

rG1ca09538d942: sys/arm64: fix COMPAT_FREEBSD32 __syscall()

Summary

It seems like _QUAD_LOWWORD was incorrectly expanded into 1,
which is correct for big endian but not little endian. This
means we always grab the padding word for the syscall number,
which is usually 0, causing SIGSYS to be delivered to the caller.
Reintroduce _QUAD_LOWWORD to fix the syscall.

PR: 290411
MFC after: 1 week

Test Plan

PR 290411 reproducer no longer bugs out after applying the patch.

Diff Detail

Repository

rG FreeBSD src repository

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Event Timeline

fuz created this revision.Tue, Oct 21, 10:18 PM

Herald added a reviewer: manu. · View Herald TranscriptTue, Oct 21, 10:18 PM

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

fuz requested review of this revision.Tue, Oct 21, 10:18 PM

Harbormaster completed remote builds in B67980: Diff 164718.Tue, Oct 21, 10:18 PM

Fixes: 8c9c3144ccfa ("Impleent COMPAT_FREEBSD32 for arm64. This is based on early work by andrew@.")

(typo intended)

sys/arm64/arm64/elf32_machdep.c
213	Is there a reason not to just use 0? We don't support big-endian and never will.

markmi_dsl-only.net added a subscriber: markmi_dsl-only.net.Tue, Oct 21, 11:02 PM

markmi_dsl-only.net added inline comments.

sys/arm64/arm64/elf32_machdep.c
213	Possibly: # grep -r "code.ap._QUAD_LOWWORD" /usr/src/sys/ /usr/src/sys/arm/arm/syscall.c: sa->code = ap[_QUAD_LOWWORD]; unless both were to be changed to 0.

fuz added inline comments.Tue, Oct 21, 11:14 PM

sys/arm64/arm64/elf32_machdep.c
213	I have done it this way to match `sys/sys/arm/arm/syscall.c`, as @markmi_dsl-only.net mentioned. I would prefer to have the same code in both paths. That said, aarch64eb is not off the cards. Maybe I'll find time for it in the future.