Re: [Qemu-devel] MIPS: UART access w/o -kernel option

[Alexander Voropay]

Alexander Voropay wrote:

> I'm still trying to run a MIPS mmon as a BIOS :)
>
> I've found one strange issue : when it runs at the
> KSEG0 region (0x80008000) with -kernel option it works fine.
> When I'm trying to run it in the MIPS BIOS region (0xbfc00000)
> it can't output anything to the UART and Qemu segfaults
> on the any keypress (not my program, but whole Qemu !)

I've found this bug  :  hw/mips_r4k.c:mips_r4k_init()

Qemu/MIPS does not initialize an ISA memory region when issued
without -kernel option. (I've added some debug output).

Whith -kernel:
cpu_register_physical_memory: start=00000000, size=08000000, offset=00000000
cpu_register_physical_memory: start=14000000, size=00010000, offset=00000050
cpu_register_physical_memory: start=100A0000, size=00020000, offset=00000060
cpu_register_physical_memory: start=E0000000, size=00400000, offset=08000000

Without -kernel:
cpu_register_physical_memory: start=00000000, size=08000000, offset=00000000
cpu_register_physical_memory: start=1FC00000, size=00020000, offset=08400010
Segmentation fault

Could someone correct this ? The ISA region and devices initialization should
be performed *before* any fileload.


P.S.  The MIPS initial state (PC=0xbfc00000) is defined twice in the qemu: 
./target-mips/translate.c:cpu_mips_init():1766
and
./hw/mips_r4k.c:mips_r4k_init()

Seems, this is a bug too.


--
-=AV=-