Re: [PATCH 3/4] hw/arm: Move armv7m_nvic.c to hw/arm/ and always enable it for arm builds

[Peter Maydell]

On Tue, 24 Sep 2019 at 05:44, Thomas Huth <address@hidden> wrote:
>
> On 23/09/2019 20.50, Peter Maydell wrote:
> > On Mon, 23 Sep 2019 at 19:36, Thomas Huth <address@hidden> wrote:
> >> Just try to change "obj-$(CONFIG_ARM_V7M) += armv7m_nvic.o" into
> >> "obj-y += armv7m_nvic.o" in hw/int/Makefile.objs, and you'll see it break:
> >>
> >>   CC      alpha-softmmu/hw/intc/armv7m_nvic.o
> >> In file included from include/hw/intc/armv7m_nvic.h:13,
> >>                  from hw/intc/armv7m_nvic.c:19:
> >> target/arm/cpu.h:1416: error: "FPCR_DZE" redefined [-Werror]
> >>  #define FPCR_DZE    (1 << 9)    /* Divide by Zero exception trap enable */
> >
> > Sure, so don't define CONFIG_ARM_V7M in a default-config for
> > a non-Arm architecture. Then you get the behaviour you want:
> > the file is compiled only for the arm targets.
>
> Sigh, the point of this series is that it should also possible to
> compile *without* CONFIG_ARM_V7M in default-configs if you want (and
> yes, there are people out there who want to be able to compile a
> minimalistic QEMU). It's currently not possible to disable this switch.
> But ok, if you're not really interested in providing a possibility to
> make qemu-system-arm a little bit more flexible in this regard, never
> mind, I'll look into other issues instead.

No, I'm happy that we should be able to compile without CONFIG_ARM_V7M
selected. I'm just confused about why you think this requires that
we move this file out of hw/intc.

Case 1: arm target, CONFIG_ARM_V7M=y (presumably in a Kconfig world
this is set by default if the user doesn't flip that switch):
obj-$(CONFIG_ARM_V7M) expands to obj-y, file compiled, OK
Case 2: arm target, CONFIG_ARM_V7M=n set by user via Kconfig:
obj-$(CONFIG_ARM_V7M) expands to obj-n, file not compiled, which is
also what we want Case 3: not an arm target, CONFIG_ARM_V7M will be
either 'n' (or empty?) and is not settable by user: expands to obj-n
again, which is also what we want

Is there some Kconfig restriction I'm not aware of that
messes things up?

thanks
-- PMM