Re: [Qemu-devel] [PATCH for-1.6] target-mips: do not raise exceptions when accessing invalid memory

[Stefan Weil]

Am 27.07.2013 22:58, schrieb Stefan Weil:
> Am 27.07.2013 22:43, schrieb Andreas Färber:
>> Am 27.07.2013 21:37, schrieb Stefan Weil:
>>> Am 27.07.2013 19:43, schrieb Peter Maydell:
>>>> On 27 July 2013 17:18, Hervé Poussineau <address@hidden> wrote:
>>>>> Another solution would be to add a big dummy memory regions on all MIPS 
>>>>> boards
>>>>> to catch memory accesses and not raise an exception. However, this means 
>>>>> that
>>>>> each MIPS board will have its own unassigned memory handler, different 
>>>>> from the
>>>>> global QEMU one.
>>>> Better would be to at least provide fake RAZ/WI implementations of
>>>> devices for the boards, rather than making the dummy region cover
>>>> the whole of the address space. Not 1.6 material, though.


For MIPS Malta, Linux boot can be fixed by handling read access for two
addresses:

0x1fbf8008
0x1bc80110

The corresponding definitions in the Linux kernel code seem to be these
lines:

#define GCMP_BASE_ADDR                  0x1fbf8000
#define GCMP_ADDRSPACE_SZ               (256 * 1024)
#define GCMP_GCB_GCMPB_OFS              0x0008          /* Global GCMP
Base */

#define MSC01_BIU_REG_BASE              0x1bc80000
#define MSC01_BIU_ADDRSPACE_SZ          (256 * 1024)
#define MSC01_SC_CFG_OFS                0x0110

=> mips_malta.c needs a handler for reads of
(GCMP_BASE_ADDR + GCMP_GCB_GCMPB_OFS) and
(MSC01_BIU_REG_BASE + MSC01_SC_CFG_OFS).

Regards,

Stefan W.