Re: [Qemu-devel] [PATCH v1 5/5] hw/arm: Add the Netduino Plus 2

[Alistair Francis]

On Sun, May 5, 2019 at 8:34 AM Peter Maydell <address@hidden> wrote:
>
> On Sat, 4 May 2019 at 06:26, Alistair Francis <address@hidden> wrote:
> > Ah, it seems like -device loader doesn't work, it looks like not
> > setting the thumb register causes this core dump:
> >
> > qemu: fatal: Lockup: can't escalate 3 to HardFault (current priority -1)
> >
> > R00=20000000 R01=00000574 R02=200015d0 R03=200015d0
> > R04=00000000 R05=00000000 R06=00000000 R07=00000000
> > R08=00000000 R09=00000000 R10=00000000 R11=00000000
> > R12=00000000 R13=ffffffe0 R14=fffffff9 R15=0800cba4
>
> Is the ELF file incorrectly setting the entry point address to not
> be a Thumb one (ie low bit set), or is the loader device not honouring
> that? (I thought that we'd fixed the latter of those recently...)

It looks like all the reset logic is correct in terms of these lines
in arm_cpu_reset():
        env->regs[13] = initial_msp & 0xFFFFFFFC;
        env->regs[15] = initial_pc & ~1;
        env->thumb = initial_pc & 1;

The problem is that vecbase is 0, as cpu->init_svtor is 0.

cpu->init_svtor is set via QOM properties in armv7m_realize() based on
the armv7m property "init-svtor".

So hopefully I should be able to just set the property "init-svtor"
for the armv7m object. I'll test that out and see how it goes.

Alistair

>
> thanks
> -- PMM