NetBSD Problem Report #59306

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Date: Thu, 17 Apr 2025 05:12:44 +0000 (UTC)
From: campbell+netbsd@mumble.net
Reply-To: campbell+netbsd@mumble.net
To: gnats-bugs@NetBSD.org
Subject: kernel longjmp(9) fails to make setjmp(9) return 1
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>Number:         59306
>Category:       port-powerpc
>Synopsis:       kernel longjmp(9) fails to make setjmp(9) return 1
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-powerpc-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Apr 17 05:15:00 +0000 2025
>Last-Modified:  Tue Apr 29 11:00:03 +0000 2025
>Originator:     Taylor R Campbell
>Release:        current
>Organization:
i'm out of clever names tonight foundation
>Environment:
>Description:
Kernel longjmp(9) is supposed to make setjmp(9) return 1 -- it doesn't take a second argument for the return value.  But the powerpc code does this:

    103 	mr %r3, %r4
    104 	blr

https://nxr.netbsd.org/xref/src/sys/arch/powerpc/powerpc/setjmp.S?r=1.4

powerpc ABI puts arguments in %r3, %r4, ..., and return value in %r3, so this returns whatever garbage is in the register for the second argument -- garbage because kernel longjmp doesn't take a second argument.
>How-To-Repeat:
code inspection
mess with ddb, probably
>Fix:
Change

mr %r3, %r4

to

li %r3, 1

>Audit-Trail:
From: "Martin Husemann" <martin@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc: 
Subject: PR/59306 CVS commit: src/sys/arch/powerpc/powerpc
Date: Tue, 29 Apr 2025 10:56:38 +0000

 Module Name:	src
 Committed By:	martin
 Date:		Tue Apr 29 10:56:38 UTC 2025

 Modified Files:
 	src/sys/arch/powerpc/powerpc: setjmp.S

 Log Message:
 PR port-powerpc/59306: kernel longjmp(9) only takes one argument,
 always make setjmp(9) return 1.
 Change as suggested by Taylor.


 To generate a diff of this commit:
 cvs rdiff -u -r1.4 -r1.5 src/sys/arch/powerpc/powerpc/setjmp.S

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

From: "Martin Husemann" <martin@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc: 
Subject: PR/59306 CVS commit: src/tests/kernel
Date: Tue, 29 Apr 2025 10:57:18 +0000

 Module Name:	src
 Committed By:	martin
 Date:		Tue Apr 29 10:57:17 UTC 2025

 Modified Files:
 	src/tests/kernel: t_setjmp.sh

 Log Message:
 PR port-powerpc/59306 has been fixed, remove expected failure.


 To generate a diff of this commit:
 cvs rdiff -u -r1.4 -r1.5 src/tests/kernel/t_setjmp.sh

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

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