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From: Richard Henderson <rth@twiddle.net>
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Date: Tue, 8 Jan 2019 08:17:00 +1000
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Subject: Re: [Qemu-devel] [Bug 1810545] Re: [alpha] Strange exception
 address reported
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To: Peter Maydell <peter.maydell@linaro.org>, QEMU Developers <qemu-devel@nongnu.org>

On 1/8/19 5:00 AM, Peter Maydell wrote:
> On Mon, 7 Jan 2019 at 18:10, Peter Maydell <peter.maydell@linaro.org> wrote:
> (re: https://bugs.launchpad.net/bugs/1810545)
> 
>> The problem seems to be that the PC we report for an OPCDEC
>> is first selected by gen_invalid()/gen_excp() in
>> target/alpha/translate.c, which uses pc_next (ie the insn's
>> address plus 4). But that is then handed through to our custom
>> PALcode (https://git.qemu.org/?p=qemu-palcode.git;a=blob;f=pal.S;h=1781c4b415700ca3a68af07fdae90ae43e722501;hb=HEAD) which does
>>   addq    p6, 4, p1  // increment past the faulting insn
>> resulting in insn + 8.
>>
>> That is, the palcode and the QEMU code have a disagreement about what
>> the (private) API between them is. I'm not sure which side is wrong and
>> should be corrected. I think the linux-user code assumes the same thing
>> that translate.c is doing, so perhaps the palcode.
> 
> Richard -- any suggestions for which side of this API we should
> be changing?

Probably the palcode side.  I'll take care of it.


r~