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Date:   Wed, 15 Nov 2000 12:17:54 -0800
From:   Jun Sun <jsun@mvista.com>
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To:     Harald Koerfgen <Harald.Koerfgen@home.ivm.de>
CC:     linux-mips@oss.sgi.com, "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>,
        Ralf Baechle <ralf@oss.sgi.com>
Subject: Re: Build failure for R3000 DECstation
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Harald Koerfgen wrote:
> > I also doubt if k0 is absolutely non-zero after a context ...
> 
> That's not the problem here, yes, it is. At least for the the CONFIG_CPU_R3000
> case. Have a look at include/asm-mips/stackframe.h, especially the R3000
> version of the RESTORE_SP_AND_RET macro.
> 

I did not doubt the non-zero value of k0.  I really doubted the
approach: a userland primitive is based on non-documented,
non-guarranteed kernel stack restoring code.  Once something changes in
kernel, you will get really obscure bugs.

Jun