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

[Peter Maydell]

On Mon, 23 Sep 2019 at 19:36, Thomas Huth <address@hidden> wrote:
>
> On 23/09/2019 20.27, Peter Maydell wrote:
> > On Mon, 23 Sep 2019 at 18:54, Thomas Huth <address@hidden> wrote:
> >> Ok, then what would you suggest to solve the problem that this file has
> >> always to be linked into the binary? I can't use "obj-y += ..." in
> >> hw/intc/Makefile.objs since that would mean that the file also gets
> >> compiled for non-Arm boards. Would you prefer a bunch of stubs instead
> >> that get used if CONFIG_ARM_V7M is not set?
> >
> > I thought obj-y was for only-this-target and obj-common-y was
> > for all-boards ?
>
> Well, obj-y is for the current target that gets compiled. But if you use
> it in a Makefile that gets used by all targets, the file gets compiled
> for each target individually.
>
> 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.

This is exactly the same as for the GICv3's arm_gicv3_cpuif.c, which
is also protected by a CONFIG_ flag that's only set by the Arm
default-configs, because it needs to be compiled as a target-specific
file for arm and only arm.

thanks
-- PMM