Re: [PATCH] drivers/irqchip: Remove function callback casts

Marc Zyngier
2020-05-24T11:46:39Z

On Sun, 24 May 2020 10:09:10 +0200
Oscar Carter <oscar.carter@gmx.com> wrote:

Hi Oscar,

Thanks for this. Comments below.

> In an effort to enable -Wcast-function-type in the top-level Makefile to
> support Control Flow Integrity builds, remove all the function callback
> casts.
>
> To do this, modify the IRQCHIP_ACPI_DECLARE macro initializing the
> acpi_probe_entry struct directly instead of use the existent macro
> ACPI_DECLARE_PROBE_ENTRY.
>
> In this new initialization use the probe_subtbl field instead of the
> probe_table field use in the ACPI_DECLARE_PROBE_ENTRY macro.

Please add *why* this is a valid transformation (probe_table and
probe_subtbl are part of a union).

>
> Signed-off-by: Oscar Carter <oscar.carter@gmx.com>
> ---
> include/linux/irqchip.h | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/irqchip.h b/include/linux/irqchip.h
> index 950e4b2458f0..1f464fd10df0 100644
> --- a/include/linux/irqchip.h
> +++ b/include/linux/irqchip.h
> @@ -39,8 +39,14 @@
> * @fn: initialization function
> */
> #define IRQCHIP_ACPI_DECLARE(name, subtable, validate, data, fn) \
> - ACPI_DECLARE_PROBE_ENTRY(irqchip, name, ACPI_SIG_MADT, \
> - subtable, validate, data, fn)
> + static const struct acpi_probe_entry __acpi_probe_##name \
> + __used __section(__irqchip_acpi_probe_table) = { \
> + .id = ACPI_SIG_MADT, \
> + .type = subtable, \
> + .subtable_valid = validate, \
> + .probe_subtbl = (acpi_tbl_entry_handler)fn, \
> + .driver_data = data, \
> + }
>

I'd rather you add an ACPI_DECLARE_SUBTABLE_PROBE_ENTRY to acpi.h, and
use that here so that we can keep the ACPI gunk in a single place.

> #ifdef CONFIG_IRQCHIP
> void irqchip_init(void);
> --
> 2.20.1
>
>

Thanks,

M.
--
Jazz is not dead. It just smells funny...