2020-05-24 08:14:24

by Oscar Carter

[permalink] [raw]
Subject: [PATCH] drivers/irqchip: Remove function callback casts

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 <[email protected]>
---
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


2020-05-24 11:48:48

by Marc Zyngier

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

On Sun, 24 May 2020 10:09:10 +0200
Oscar Carter <[email protected]> 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 <[email protected]>
> ---
> 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...

2020-05-24 16:11:53

by Oscar Carter

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

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 <[email protected]> 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 <[email protected]>
> > ---
> > 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

2020-05-24 16:21:00

by Marc Zyngier

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

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 <[email protected]> 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 <[email protected]>
>> > ---
>> > 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...

2020-05-26 17:34:56

by Oscar Carter

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

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