Re: [Qemu-arm] Booting Cortex-M3 Linux kernels in qemu

[Guenter Roeck]

Hi Peter,

On 06/15/2018 02:16 AM, Peter Maydell wrote:
> On 14 June 2018 at 22:54, Guenter Roeck <address@hidden> wrote:
> > qemu supports a number of boards with Cortex-M3 CPU. One board supported
> > by both qemu and Linux is an385.
> >
> > As part of my kernel testing effort, it would be great to be able to boot
> > a non-MMU kernel. However, nothing I tried works.
> >
> > Is it possible to boot a Cortex-M3 Linux kernel with qemu ? If yes, does
> > anyone happen to know how to do it ?
>
> I've never tried to boot Linux, only a few RTOS-ish things.
> mps2-an385 is probably a reasonably good choice to start with.
> Note that it is missing quite a lot of devices, so you might
> need to configure Linux not to try to use them (and also
> let us know which ones would be useful for us to implement...)
> If you pass QEMU the command line -d unimp option it should log
> accesses to ranges and devices we don't implement, which may
> throw up some useful hints.
>
> Also for M-profile I'd suggest always trying with the most
> recent QEMU if you aren't already, since we've been working
> actively on it recently.

I tried various versions, but usually I am on the latest version
or even mainline (in this case it is v2.12).

Anyway, my problem is much more basic than device support. Whatever I try,
I always get

qemu: fatal: Lockup: can't escalate 3 to HardFault (current priority -1)

R00=00000000 R01=00000000 R02=00000000 R03=00000000
R04=00000000 R05=00000000 R06=00000000 R07=00000000
R08=00000000 R09=00000000 R10=00000000 R11=00000000
R12=00000000 R13=ffffffe0 R14=fffffff9 R15=00000000
XPSR=40000003 -Z-- A handler
FPSCR: 00000000

even when I use a toolchain specifically built for Cortex-M3 and thumb2,
and no matter which image I try to load. Presumably that means that it
tries to execute or jump to a non-thumb2 instruction, but that doesn't
really help me. Any idea, or should I just give up ?

Thanks,
Guenter