Re: [PATCH v2 7/8] mips: allow compiling out CONFIG_MIPS_ITU

[Philippe Mathieu-Daudé]

Hi Paolo,

On 7/2/24 12:14, Paolo Bonzini wrote:
> itc_reconfigure() is referenced from TCG, provide a stub if needed.
> This makes it possible to build a QEMU binary that only includes
> boards without a CPS device (only Malta and Boston create one).
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>   hw/mips/mips_itu-stub.c | 26 ++++++++++++++++++++++++++
>   hw/mips/meson.build     |  1 +
>   2 files changed, 27 insertions(+)
>   create mode 100644 hw/mips/mips_itu-stub.c
>
> diff --git a/hw/mips/mips_itu-stub.c b/hw/mips/mips_itu-stub.c
> new file mode 100644
> index 00000000000..4cc82b8461f
> --- /dev/null
> +++ b/hw/mips/mips_itu-stub.c
> @@ -0,0 +1,26 @@
> +/*
> + * Inter-Thread Communication Unit emulation.
> + *
> + * Copyright (c) 2016 Imagination Technologies
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see <http://www.gnu.org/licenses/>.

This is your code addition, so "Inter-Thread Communication Unit stubs" /
RH / SPDX GPLv2-or-later.

> + */
> +
> +#include "qemu/osdep.h"
> +#include "hw/misc/mips_itu.h"
> +
> +void itc_reconfigure(MIPSITUState *tag)
> +{
> +    abort();

As Zoltan suggested, g_assert_not_reached(). Indeed this path
can't be reached without ITU, TCG won't emit anything and will
call instead:

    qemu_log_mask(LOG_UNIMP, "mthc0 %s (reg %d sel %d)\n",
                  register_name, reg, sel);

I'm reluctant to add stubs, but since it helps you (hoping we
can figure a clean way to split architectural access to hw/ from
tcg/ one day):

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

Regards,

Phil.