syscallarg_t: Add a type for system call arguments
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Authored by brooks on Jan 7 2022, 4:44 PM.

Details

Reviewers

kib
jhb
jrtc27
manu
imp

Commits

rGb1ad6a9000c3: syscallarg_t: Add a type for system call arguments
rG1544e0f5d1f1: syscallarg_t: Add a type for system call arguments

Summary

This more clearly differentiates system call arguments from integer
registers and return values. On current architectures it has no effect,
but on architectures where pointers are not integers (CHERI) and may
not even share registers (CHERI-MIPS) it is necessiary to differentiate
between system call arguments (syscallarg_t) and integer register values
(register_t).

Obtained from: CheriBSD

Diff Detail

Repository

rS FreeBSD src repository - subversion

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Unit

No Test Coverage

Build Status

Buildable 43856
Build 40744: arc lint + arc unit

Event Timeline

brooks created this revision.Jan 7 2022, 4:44 PM

Herald added a reviewer: manu. · View Herald TranscriptJan 7 2022, 4:44 PM

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

brooks requested review of this revision.Jan 7 2022, 4:44 PM

Harbormaster completed remote builds in B43767: Diff 101102.Jan 7 2022, 4:44 PM

I like this.

This revision is now accepted and ready to land.Jan 7 2022, 4:46 PM

👍

Do you plan to also update other architectures and ABIs?

Update amd64 and arm

This revision now requires review to proceed.Jan 7 2022, 10:25 PM

Harbormaster completed remote builds in B43774: Diff 101110.Jan 7 2022, 10:25 PM

In D33780#764080, @andrew wrote:

Do you plan to also update other architectures and ABIs?

I've done arm and amd64. I've not touched powerpc because it follows a unique model.

kib added inline comments.Jan 8 2022, 2:48 AM

sys/sys/types.h
273	Can we have it named less verbose, e.g. scarg_t ?
sys/vm/vm_mmap.c
423	Is this cast needed at all?

Remove needless cast

Harbormaster completed remote builds in B43856: Diff 101304.Jan 11 2022, 5:34 PM

brooks marked an inline comment as done.Jan 11 2022, 5:35 PM

brooks added inline comments.

sys/vm/vm_mmap.c
423	It doesn't appear to be. I've removed it.

brooks marked an inline comment as done.Jan 11 2022, 5:37 PM

brooks added inline comments.

sys/sys/types.h
273	I don't see the value in trading a more obfuscated name for 5 bytes per use of a rarely used type.

kib accepted this revision.Jan 12 2022, 4:53 AM

kib added inline comments.

sys/sys/types.h
273	The lines where syscallarg_t needs to be spelled, get too long. Typically if you need to cast, you need to repeat the type name in the same expression one more time, so it is 5-10 chars lost out of 72.

This revision is now accepted and ready to land.Jan 12 2022, 4:53 AM

Closed by commit rG1544e0f5d1f1: syscallarg_t: Add a type for system call arguments (authored by brooks). · Explain WhyJan 12 2022, 10:52 PM

This revision was automatically updated to reflect the committed changes.

brooks added a commit: rG1544e0f5d1f1: syscallarg_t: Add a type for system call arguments.

brooks added a reverting change: rG0910a41ef3b9: Revert "syscallarg_t: Add a type for system call arguments".Jan 12 2022, 11:31 PM

brooks added a commit: rGb1ad6a9000c3: syscallarg_t: Add a type for system call arguments.Mar 28 2022, 6:45 PM