From owner-freebsd-emulation  Wed Aug 25 10:22: 9 1999
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Date: Thu, 26 Aug 1999 03:21:24 +1000
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199908251721.DAA25993@godzilla.zeta.org.au>
To: bde@zeta.org.au, marcel@scc.nl
Subject: Re: SIGBUS for threaded Linux binaries (glibc2.1) [PSL_AC related?]
Cc: emulation@FreeBSD.ORG
Sender: owner-freebsd-emulation@FreeBSD.ORG
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>> This means that the stack is misaligned.  This seems to be an emulator
>> bug.  The stack is also misaligned for an old version of Linux `cat'
>> when I attach to it while it is waiting for input.
>
>You're right. `linux_sigcode' in linux_locore.s doesn't have the 'right'
>size. Consequently `linux_szsigcode' is no multiple of 4 which results in a
>misaligned stack. I'll commit the fix shortly.

This is ELF breakage.  I've even noticed the problem before.  `.align 2'
should be `.p2align 2', or better, ALIGN_TEXT as in locore.s.

The committed fix is wrong.  `.align 4' gives 16-byte alignment, which
is harmless but bogotifies the comment.  Why not use the standard macro?

There are also broken .align statements in:
    apic_ipl.s (two .align 2's, one with a comment saying that things MUST
		be 32-bit aligned)
    svr4_locore.s (same bugs as in linux_locore.s).

There are also dubious .align statements in:
    alpha/locore.s (.align 3)
    alpha/prom_disp.s (.align 4)
At least the first is apparently a power of 2 aligne statement and should
be spelled .p2align.

Bruce


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