[PATCH] drivers/irqchip: Remove function callback casts

[PATCH] drivers/irqchip: Remove function callback casts

[Oscar Carter]

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.

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,				\
+		}

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

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

[Marc Zyngier]

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...

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

[Oscar Carter]

Hi Marc,

On Sun, May 24, 2020 at 12:46:34PM +0100, Marc Zyngier wrote:
> 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).

Ok, I will add a more detailed explanation.

> > 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.

Ok, I will do the changes you suggested and I will resend a new version.
Later, I will also send a series to clean up the checkpatch warnings and
errors for the acpi.h header.

> >  #ifdef CONFIG_IRQCHIP
> >  void irqchip_init(void);
> > --
> > 2.20.1
> >
> >
>
> Thanks,
>
> 	M.
> --
> Jazz is not dead. It just smells funny...

Thanks,
Oscar Carter

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

[Marc Zyngier]

On 2020-05-24 17:06, Oscar Carter wrote:
> Hi Marc,
> 
> On Sun, May 24, 2020 at 12:46:34PM +0100, Marc Zyngier wrote:
>> 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).
> 
> Ok, I will add a more detailed explanation.
> 
>> > 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.
> 
> Ok, I will do the changes you suggested and I will resend a new 
> version.
> Later, I will also send a series to clean up the checkpatch warnings 
> and
> errors for the acpi.h header.

Not necessarily a good idea. Churn for the sake of keeping checkpatch
at bay is pretty pointless. Do fix bugs if you spot any, but please
exercise judgement.

Thanks,

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

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

[Oscar Carter]

Hi Marc,

On Sun, May 24, 2020 at 05:16:41PM +0100, Marc Zyngier wrote:
> On 2020-05-24 17:06, Oscar Carter wrote:
>
> > Ok, I will do the changes you suggested and I will resend a new version.
> > Later, I will also send a series to clean up the checkpatch warnings and
> > errors for the acpi.h header.
>
> Not necessarily a good idea. Churn for the sake of keeping checkpatch
> at bay is pretty pointless. Do fix bugs if you spot any, but please
> exercise judgement.

Ok, thanks for your advise. For now I will only fix the part related to this
patch.

> Thanks,
>
>         M.
> --
> Jazz is not dead. It just smells funny...

Thanks,
Oscar