Re: [Qemu-devel] [PATCH 02/10 v11] linux-user: Support tilegx architecture in linux-user

[Peter Maydell]

On 3 June 2015 at 16:10, Chris Metcalf <address@hidden> wrote:
> On 06/03/2015 08:47 AM, Chen Gang wrote:
>>
>> On 06/03/2015 08:34 PM, Peter Maydell wrote:
>>> You must do something. You can't allow guest code (even
>>> broken guest code) to make QEMU assert. You need to find
>>> out what the hardware does here, and do that.
>>>
>> OK, what you said sounds reasonable to me. I will check what to do next
>> for the 56..62 registers (at present, I guess, we need generate a
>> hardware exception, and its default handler will do nothing).
>
>
> The registers in question are mapped directly to the on-chip
> networks.
>
> 56 - sn (static network)
> 57 - idn0 (internal dynamic network, demux 0)
> 58 - idn1 (internal dynamic network, demux 1)
> 59 - udn0 (user dynamic network, demux 0)
> 60 - udn1 (user dynamic network, demux 1)
> 61 - udn2 (user dynamic network, demux 2)
> 62 - udn3 (user dynamic network, demux 3)
>
> The "sn" is obsoleted in tilegx so acts just like "zero".
>
> Accessing idn0 or idn1 will generate an IDN_ACCESS exception,
> and accessing udn0..udn3 will generate a UDN_ACCESS exception;
> either of those becomes a SIGILL to a userspace application
> with code ILL_PRVREG.

Presumably this applies for all register accesses, not
just atomic instructions?

thanks
-- PMM