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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Jan Beulich <jbeulich@novell.com>
Cc: Ingo Molnar <mingo@elte.hu>,
	the arch/x86 maintainers <x86@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Xen-devel <xen-devel@lists.xensource.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [Xen-devel] [PATCH 2/5] xen/x86-64: clean up warnings	 aboutIST-using traps
Date: Fri, 08 May 2009 08:23:01 -0700	[thread overview]
Message-ID: <4A044E55.20803@goop.org> (raw)
In-Reply-To: <4A03F947.76EA.0078.0@novell.com>

Jan Beulich wrote:
>> else if (addr == (unsigned long)int3)
>> 		addr = (unsigned long)xen_int3;
>> -	else
>> -		WARN_ON(val->ist != 0);
>> +	else if (addr == (unsigned long)double_fault ||
>> +		 addr == (unsigned long)stack_segment) {
>>     
>
> I don't think you want to exclude handling stack faults: Ordinary memory
> references using rsp or rbp as the base register will cause these instead
> of general protection faults when the resulting effective address is non-
> canonical.
>   

So even usermode memory accesses?  Ew.  Well, we can run the trap 
handler on the normal kernel stack in that case.  I'll cook something up.

    J

WARNING: multiple messages have this Message-ID (diff)
From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Jan Beulich <jbeulich@novell.com>
Cc: Ingo Molnar <mingo@elte.hu>,
	the arch/x86 maintainers <x86@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Xen-devel <xen-devel@lists.xensource.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/5] xen/x86-64: clean up warnings	 aboutIST-using traps
Date: Fri, 08 May 2009 08:23:01 -0700	[thread overview]
Message-ID: <4A044E55.20803@goop.org> (raw)
In-Reply-To: <4A03F947.76EA.0078.0@novell.com>

Jan Beulich wrote:
>> else if (addr == (unsigned long)int3)
>> 		addr = (unsigned long)xen_int3;
>> -	else
>> -		WARN_ON(val->ist != 0);
>> +	else if (addr == (unsigned long)double_fault ||
>> +		 addr == (unsigned long)stack_segment) {
>>     
>
> I don't think you want to exclude handling stack faults: Ordinary memory
> references using rsp or rbp as the base register will cause these instead
> of general protection faults when the resulting effective address is non-
> canonical.
>   

So even usermode memory accesses?  Ew.  Well, we can run the trap 
handler on the normal kernel stack in that case.  I'll cook something up.

    J

  parent reply	other threads:[~2009-05-08 15:23 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-07 18:56 [PATCH 2/5] xen/x86-64: clean up warnings about IST-using traps Jeremy Fitzhardinge
2009-05-08  7:20 ` [Xen-devel] [PATCH 2/5] xen/x86-64: clean up warnings aboutIST-using traps Jan Beulich
2009-05-08  7:20   ` Jan Beulich
2009-05-08  8:58   ` [Xen-devel] " Ingo Molnar
2009-05-08  8:58     ` Ingo Molnar
2009-05-08 15:31     ` [Xen-devel] " Jeremy Fitzhardinge
2009-05-08 15:31       ` Jeremy Fitzhardinge
2009-05-08 15:23   ` Jeremy Fitzhardinge [this message]
2009-05-08 15:23     ` Jeremy Fitzhardinge
2009-05-08 15:30     ` [Xen-devel] [PATCH 2/5] xen/x86-64: clean up warnings aboutIST-usingtraps Jan Beulich
2009-05-08 15:30       ` Jan Beulich

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