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Date: Thu, 20 Mar 2008 15:15:00 +1100
From: Paul Mackerras <paulus@samba.org>
To: Roland McGrath <roland@redhat.com>
Subject: Re: unprivileged use of MSR_SE
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Roland McGrath writes:

> I'd like to clean this up for powerpc too.  If there is no way at all for
> user-mode to set MSR_SE, then it doesn't much matter whether it shows up
> when ptrace reads it--ptrace just needs to ignore attempts to set it.  So
> if there's no reason not to, what I would do is remove MSR_SE from the
> MSR_DEBUGCHANGE mask and make sigreturn always clear MSR_SE.

OK, I found MSR_DEBUGCHANGE, it's in ptrace.c. :)  So it only applies
to attempts to change the MSR of a process using ptrace.  So, what you
want is just to disallow changing MSR via PTRACE_POKEUSR or
equivalent, then?

Paul.