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To: John Baldwin <jhb@FreeBSD.org>
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Date: Fri, 02 May 2003 15:12:36 -0700
From: Peter Wemm <peter@wemm.org>
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cc: Perforce Change Reviews <perforce@freebsd.org>
Subject: Re: PERFORCE change 29745 for review 
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John Baldwin wrote:
> 
> On 25-Apr-2003 Peter Wemm wrote:
> > http://perforce.freebsd.org/chv.cgi?CH=29745
> > 
> > Change 29745 by peter@peter_daintree on 2003/04/25 16:01:39
> > 
> >       Add a pcb flag to indicate that a full trapframe restore
> >       is required, even from syscall.. eg: a sigreturn(2).
> >       I'm not sure if this is the right place for it.  mdthread
> >       perhaps?  Anyway, it'll do for now.
> 
> mdthread sounds right.  Alpha uses a flags field on the trapframe to
> accomplish this:
> 
> sys/alpha/include/frame.h
> #define FRAME_FLAGS             27
> #define FRAME_FLAGS_SYSCALL             1 /* partial frame for syscalls */

They put the frames in the space reserved for the 'zero' register if I
recall correctly.

On a side note, there are times when I'd like to move the pcb stuff into
mdthread..

Cheers,
-Peter
--
Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com
"All of this is for nothing if we don't go to the stars" - JMS/B5