Re: [Qemu-devel] [V6, 2/7] nios2: Add architecture emulation support

[Guenter Roeck]

Hi Marek,

On 11/07/2016 10:14 AM, Marek Vasut wrote:
> On 11/07/2016 04:58 AM, Guenter Roeck wrote:
> > On Tue, Oct 25, 2016 at 09:57:43PM +0200, Marek Vasut wrote:
> > > From: Chris Wulff <address@hidden>
> > >
> > > Add support for emulating Altera NiosII R1 architecture into qemu.
> > > This patch is based on previous work by Chris Wulff from 2012 and
> > > updated to latest mainline QEMU.
> > >
> > > Signed-off-by: Marek Vasut <address@hidden>
> > > Cc: Chris Wulff <address@hidden>
> > > Cc: Jeff Da Silva <address@hidden>
> > > Cc: Ley Foon Tan <address@hidden>
> > > Cc: Sandra Loosemore <address@hidden>
> > > Cc: Yves Vandervennet <address@hidden>
> > > ---
> > > V3: Thorough cleanup, deal with the review comments all over the place
> > > V4: - Use extract32()
> > >     - Fix gen_goto_tb() , suppress tcg_gen_goto_tb()
> > >     - Clean up gen_check_supervisor() helper
> > >     - Use TCGMemOp type for flags
> > >     - Drop jump labels from wrctl/rdctl
> > >     - More TCG cleanup
> > > V5: - Simplify load/store handling
> > >     - Handle loads into R_ZERO from protected page, add comment
> > > V6: - Fix division opcode handling
> > >     - Add missing disas handling
> > >     - V5 review comments cleanup
> > > ---
> > [ ... ]
> >
> > > diff --git a/target-nios2/cpu.h b/target-nios2/cpu.h
> > > new file mode 100644
> > > index 0000000..17c9a0f
> > [ ... ]
> >
> > > +static inline void cpu_get_tb_cpu_state(CPUNios2State *env, target_ulong *pc,
> > > +                                        target_ulong *cs_base, uint32_t *flags)
> > > +{
> > > +    *pc = env->regs[R_PC];
> > > +    *cs_base = 0;
> > > +    *flags = (env->regs[CR_STATUS] & (CR_STATUS_EH | CR_STATUS_U));
> > > +}
> > > +
> > > +#endif /* CPU_NIOS2_H */
> > > +
> >
> > The empty line at the end results in a whitespace message from git.
>
> Dropped, thanks. Is there anything else or is this patchset starting to
> become acceptable ?

Hard for me to say. I tried to build and run the series with the latest linux
kernel (v4.9-rc4), but it is stuck in early boot. I tried with 10m50_defconfig
and 10m50_devboard.dtb. gcc is 6.1.0 built with buildroot, though I also tried
with toolchains from CodeSourcery. Obviously I have no idea if there is a
kernel bug or a qemu bug or a problem with the command line I used.

Here is my command line:

qemu-system-nios2 -M 10m50-ghrd -kernel vmlinux -dtb 10m50_devboard.dtb \
        -append "earlycon=uart8250,mmio32,0x18001600,115200n8 console=ttyS0"

This may be wrong, but the boot is stuck in an endless loop in mark_bootmem(),
which seems early and odd. I tried with both vmlinux and 
arch/nios2/boot/vmImage,
with the same results.

Can you provide a working command line and kernel version, and/or directions how
to create a working image if I need to run the image, for example, from u-boot ?
Sorry if that is posted somewhere and I missed it.

> I'll wait a bit before you finish discussing the whitespace errors in
> 1/7 with Sandra.

I can't really comment on the whitespace issues; the qemu maintainers will have
to decide if they can accept this patch as-is. I am sure they will appreciate
a heads-up, though.

Thanks,
Guenter