[PATCH v3 0/2] drivers/irqchip: Remove function callback casts

[PATCH v3 0/2] 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, there are the need to remove all
the function callback casts.

The first patch creates a macro called ACPI_DECLARE_SUBTABLE_PROBE_ENTRY
to initialize the acpi_probe_entry struct using the probe_subtbl field
instead of the probe_table field to avoid function cast mismatches.

The second patch modifies the IRQCHIP_ACPI_DECLARE macro to use the new
defined macro ACPI_DECLARE_SUBTABLE_PROBE_ENTRY instead of the macro
ACPI_DECLARE_PROBE_ENTRY. Also, modifies the prototype of the functions
used by the invocation of the IRQCHIP_ACPI_DECLARE macro to match all the
parameters.

Changelog v1->v2
- Add more details in the commit changelog to clarify the changes (Marc
  Zyngier)
- Declare a new macro called ACPI_DECLARE_SUBTABLE_PROBE_ENTRY (Marc
  Zyngier)
- In the IRQCHIP_ACPI_DECLARE use the new defined macro (Marc Zyngier)

Changelog v2->v3
- Remove the cast of the macro ACPI_DECLARE_SUBTABLE_PROBE_ENTRY (Marc
  Zyngier)
- Change the prototype of the functions used by the invocation of the
  macro IRQCHIP_ACPI_DECLARE (Marc Zyngier)
- Split the changes in two patches.
- Add these two lines, to give credit to Marc Zyngier
  Signed-off-by: Marc Zyngier <maz@kernel.org>
  Signed-off-by: Oscar Carter <oscar.carter@gmx.com>

Oscar Carter (2):
  drivers/irqchip: Add new macro ACPI_DECLARE_SUBTABLE_PROBE_ENTRY
  drivers/irqchip: Use new macro ACPI_DECLARE_SUBTABLE_PROBE_ENTRY

 drivers/irqchip/irq-gic-v3.c |  2 +-
 drivers/irqchip/irq-gic.c    |  2 +-
 include/linux/acpi.h         | 11 +++++++++++
 include/linux/irqchip.h      |  5 +++--
 4 files changed, 16 insertions(+), 4 deletions(-)

--
2.20.1

[PATCH v3 1/2] drivers/irqchip: Add new macro ACPI_DECLARE_SUBTABLE_PROBE_ENTRY

[Oscar Carter]

In an effort to enable -Wcast-function-type in the top-level Makefile to
support Control Flow Integrity builds, there are the need to remove all
the function callback casts.

To do this, create a new macro called ACPI_DECLARE_SUBTABLE_PROBE_ENTRY
to initialize the acpi_probe_entry struct using the probe_subtbl field
instead of the probe_table field. This is a previous work to be able to
modify the IRQCHIP_ACPI_DECLARE macro to use this new defined macro.

Even though these two commented fields are part of a union, this is
necessary to avoid function cast mismatches. That is, due to the
IRQCHIP_ACPI_DECLARE invocations use as last parameter a function with
the protoype "int (*func)(struct acpi_subtable_header *, const unsigned
long)" it's necessary that this macro initialize the probe_subtbl field
of the acpi_probe_entry struct and not the probe_table field.

Co-developed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Oscar Carter <oscar.carter@gmx.com>
---
 include/linux/acpi.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index d661cd0ee64d..cf74e044a570 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1154,6 +1154,17 @@ struct acpi_probe_entry {
 			.driver_data = data, 				\
 		   }

+#define ACPI_DECLARE_SUBTABLE_PROBE_ENTRY(table, name, table_id,	\
+					  subtable, valid, data, fn)	\
+	static const struct acpi_probe_entry __acpi_probe_##name	\
+		__used __section(__##table##_acpi_probe_table) = {	\
+			.id = table_id,					\
+			.type = subtable,				\
+			.subtable_valid = valid,			\
+			.probe_subtbl = fn,				\
+			.driver_data = data,				\
+		}
+
 #define ACPI_PROBE_TABLE(name)		__##name##_acpi_probe_table
 #define ACPI_PROBE_TABLE_END(name)	__##name##_acpi_probe_table_end

--
2.20.1

[PATCH v3 2/2] drivers/irqchip: Use new macro ACPI_DECLARE_SUBTABLE_PROBE_ENTRY

[Oscar Carter]

In an effort to enable -Wcast-function-type in the top-level Makefile to
support Control Flow Integrity builds, there are the need to remove all
the function callback casts.

To do this, modify the IRQCHIP_ACPI_DECLARE macro to use the new defined
macro ACPI_DECLARE_SUBTABLE_PROBE_ENTRY instead of the macro
ACPI_DECLARE_PROBE_ENTRY. This is necessary to be able to initialize the
the acpi_probe_entry struct using the probe_subtbl field instead of the
probe_table field and avoid function cast mismatches.

Also, modify the prototype of the functions used by the invocation of the
IRQCHIP_ACPI_DECLARE macro to match all the parameters.

Co-developed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Oscar Carter <oscar.carter@gmx.com>
---
 drivers/irqchip/irq-gic-v3.c | 2 +-
 drivers/irqchip/irq-gic.c    | 2 +-
 include/linux/irqchip.h      | 5 +++--
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index d7006ef18a0d..3870e9d4d3a8 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -2117,7 +2117,7 @@ static void __init gic_acpi_setup_kvm_info(void)
 }

 static int __init
-gic_acpi_init(struct acpi_subtable_header *header, const unsigned long end)
+gic_acpi_init(union acpi_subtable_headers *header, const unsigned long end)
 {
 	struct acpi_madt_generic_distributor *dist;
 	struct fwnode_handle *domain_handle;
diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index 30ab623343d3..fc431857ce90 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -1593,7 +1593,7 @@ static void __init gic_acpi_setup_kvm_info(void)
 	gic_set_kvm_info(&gic_v2_kvm_info);
 }

-static int __init gic_v2_acpi_init(struct acpi_subtable_header *header,
+static int __init gic_v2_acpi_init(union acpi_subtable_headers *header,
 				   const unsigned long end)
 {
 	struct acpi_madt_generic_distributor *dist;
diff --git a/include/linux/irqchip.h b/include/linux/irqchip.h
index 950e4b2458f0..447f22880a69 100644
--- a/include/linux/irqchip.h
+++ b/include/linux/irqchip.h
@@ -39,8 +39,9 @@
  * @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)
+	ACPI_DECLARE_SUBTABLE_PROBE_ENTRY(irqchip, name,		\
+					  ACPI_SIG_MADT, subtable,	\
+					  validate, data, fn)

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

Re: [PATCH v3 2/2] drivers/irqchip: Use new macro ACPI_DECLARE_SUBTABLE_PROBE_ENTRY

[Marc Zyngier]

Hi Oscar,

On 2020-05-29 18:18, Oscar Carter wrote:
> In an effort to enable -Wcast-function-type in the top-level Makefile 
> to
> support Control Flow Integrity builds, there are the need to remove all
> the function callback casts.
> 
> To do this, modify the IRQCHIP_ACPI_DECLARE macro to use the new 
> defined
> macro ACPI_DECLARE_SUBTABLE_PROBE_ENTRY instead of the macro
> ACPI_DECLARE_PROBE_ENTRY. This is necessary to be able to initialize 
> the
> the acpi_probe_entry struct using the probe_subtbl field instead of the
> probe_table field and avoid function cast mismatches.
> 
> Also, modify the prototype of the functions used by the invocation of 
> the
> IRQCHIP_ACPI_DECLARE macro to match all the parameters.
> 
> Co-developed-by: Marc Zyngier <maz@kernel.org>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> Signed-off-by: Oscar Carter <oscar.carter@gmx.com>
> ---
>  drivers/irqchip/irq-gic-v3.c | 2 +-
>  drivers/irqchip/irq-gic.c    | 2 +-
>  include/linux/irqchip.h      | 5 +++--
>  3 files changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-gic-v3.c 
> b/drivers/irqchip/irq-gic-v3.c
> index d7006ef18a0d..3870e9d4d3a8 100644
> --- a/drivers/irqchip/irq-gic-v3.c
> +++ b/drivers/irqchip/irq-gic-v3.c
> @@ -2117,7 +2117,7 @@ static void __init gic_acpi_setup_kvm_info(void)
>  }
> 
>  static int __init
> -gic_acpi_init(struct acpi_subtable_header *header, const unsigned long 
> end)
> +gic_acpi_init(union acpi_subtable_headers *header, const unsigned long 
> end)
>  {
>  	struct acpi_madt_generic_distributor *dist;
>  	struct fwnode_handle *domain_handle;
> diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
> index 30ab623343d3..fc431857ce90 100644
> --- a/drivers/irqchip/irq-gic.c
> +++ b/drivers/irqchip/irq-gic.c
> @@ -1593,7 +1593,7 @@ static void __init gic_acpi_setup_kvm_info(void)
>  	gic_set_kvm_info(&gic_v2_kvm_info);
>  }
> 
> -static int __init gic_v2_acpi_init(struct acpi_subtable_header 
> *header,
> +static int __init gic_v2_acpi_init(union acpi_subtable_headers 
> *header,
>  				   const unsigned long end)
>  {
>  	struct acpi_madt_generic_distributor *dist;
> diff --git a/include/linux/irqchip.h b/include/linux/irqchip.h
> index 950e4b2458f0..447f22880a69 100644
> --- a/include/linux/irqchip.h
> +++ b/include647b532275bbe/linux/irqchip.h
> @@ -39,8 +39,9 @@
>   * @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)
> +	ACPI_DECLARE_SUBTABLE_PROBE_ENTRY(irqchip, name,		\
> +					  ACPI_SIG_MADT, subtable,	\
> +					  validate, data, fn)
> 
>  #ifdef CONFIG_IRQCHIP
>  void irqchip_init(void);
> --
> 2.20.1

I can't help but notice that you have left the cast in 
ACPI_DECLARE_PROBE_ENTRY, which should definitely go. Probably worth a 
third patch.

Thanks,

         M.

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

Re: [PATCH v3 2/2] drivers/irqchip: Use new macro ACPI_DECLARE_SUBTABLE_PROBE_ENTRY

[Oscar Carter]

Hi Marc,

On Sat, May 30, 2020 at 10:34:51AM +0100, Marc Zyngier wrote:
>
> I can't help but notice that you have left the cast in
> ACPI_DECLARE_PROBE_ENTRY, which should definitely go. Probably worth a third
> patch.

Ok, I remove it and resend a new version.

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

Thanks,
Oscar Carter