From owner-freebsd-current  Fri Jul  5 20: 1:53 2002
Delivered-To: freebsd-current@freebsd.org
Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 6CE8837B400
	for <current@FreeBSD.ORG>; Fri,  5 Jul 2002 20:01:49 -0700 (PDT)
Received: from web20907.mail.yahoo.com (web20907.mail.yahoo.com [216.136.226.229])
	by mx1.FreeBSD.org (Postfix) with SMTP id 3833C43E31
	for <current@FreeBSD.ORG>; Fri,  5 Jul 2002 20:01:49 -0700 (PDT)
	(envelope-from bsddiy@yahoo.com)
Message-ID: <20020706030149.42503.qmail@web20907.mail.yahoo.com>
Received: from [218.108.150.59] by web20907.mail.yahoo.com via HTTP; Fri, 05 Jul 2002 20:01:49 PDT
Date: Fri, 5 Jul 2002 20:01:49 -0700 (PDT)
From: David Xu <bsddiy@yahoo.com>
To: Julian Elischer <julian@elischer.org>
Cc: Peter Wemm <peter@wemm.org>,
	FreeBSD current users <current@FreeBSD.ORG>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Sender: owner-freebsd-current@FreeBSD.ORG
Precedence: bulk
List-ID: <freebsd-current.FreeBSD.ORG>
List-Archive: <http://docs.freebsd.org/mail/> (Web Archive)
List-Help: <mailto:majordomo@FreeBSD.ORG?subject=help> (List Instructions)
List-Subscribe: <mailto:majordomo@FreeBSD.ORG?subject=subscribe%20freebsd-current>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20freebsd-current>
X-Loop: FreeBSD.ORG


----- Original Message ----- 
From: "Julian Elischer" <julian@elischer.org>
To: "Peter Wemm" <peter@wemm.org>
Cc: "FreeBSD current users" <current@FreeBSD.ORG>
Sent: Saturday, July 06, 2002 8:43 AM
Subject: i386 trap code


> 
> Looking at i386/exception.s
> one sees:
> ###################################
>         .globl  alltraps
>         .type   alltraps,@function
> alltraps:
>         pushal
>         pushl   %ds
>         pushl   %es
>         pushl   %fs
> alltraps_with_regs_pushed:
>         mov     $KDSEL,%ax
>         mov     %ax,%ds
>         mov     %ax,%es
>         mov     $KPSEL,%ax
>         mov     %ax,%fs
>         FAKE_MCOUNT(13*4(%esp))
> calltrap:
>         FAKE_MCOUNT(btrap)              /* init "from" btrap -> calltrap
> */
>         call    trap
> 
>         /*
>          * Return via doreti to handle ASTs.
>          */
>         MEXITCOUNT
>         jmp     doreti
> #######################################
> 
> but one has to look in isa/ipl.s to find:
> ########################################
>         SUPERALIGN_TEXT
>         .type   doreti,@function
> doreti:
>         FAKE_MCOUNT(bintr)              /* init "from" bintr -> doreti */
> doreti_next:
>         /*
>          * Check if ASTs can be handled now.  PSL_VM must be checked first
>          * since segment registers only have an RPL in non-VM86 mode.
>          */
>         testl   $PSL_VM,TF_EFLAGS(%esp) /* are we in vm86 mode? */
>         jz      doreti_notvm86
>         cmpl    $1,in_vm86call          /* are we in a vm86 call? */

sorry for a bit OT, does anyone see this in_vm86call crazy global variable?
it prevents two CPUs to trap into VM86 model :(
if you have interest in fixing this problem,  please have a look at PR :

http://www.freebsd.org/cgi/query-pr.cgi?pr=i386/38223

I have also fixed the problem that VM86 call is preempted by interrupt
threads and causes system crash. newest patch can always be gotten from :
http://opensource.zjonline.com.cn/freebsd/vm86patch.tgz

-David Xu


__________________________________________________
Do You Yahoo!?
Sign up for SBC Yahoo! Dial - First Month Free
http://sbc.yahoo.com

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-current" in the body of the message