[PATCH v5 0/3] drivers/acpi: Remove function callback casts

[PATCH v5 0/3] drivers/acpi: 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 in the acpi driver.

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.

The third patch removes the function cast in the ACPI_DECLARE_PROBE_ENTRY
macro to ensure that the functions passed as a last parameter to this macro
have the right prototype. This macro is used only in another macro
called "TIMER_ACPI_DECLARE". An this is used only in the file:

drivers/clocksource/arm_arch_timer.c

In this file, the function used in the last parameter of the
TIMER_ACPI_DECLARE macro already has the right prototype. So there is no
need to modify its prototype.

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
  Co-developed-by: Marc Zyngier <maz@kernel.org>
  Signed-off-by: Marc Zyngier <maz@kernel.org>

Changelog v3->v4
- Add a new patch to remove the cast of the macro
  ACPI_DECLARE_PROBE_ENTRY (Marc Zyngier)
- Change the subject of the first patch

Changelog v4->v5
- Add the following lines removed by error in the v4 version:
  Co-developed-by: Marc Zyngier <maz@kernel.org>
  Signed-off-by: Marc Zyngier <maz@kernel.org>

Oscar Carter (3):
  drivers/acpi: Add new macro ACPI_DECLARE_SUBTABLE_PROBE_ENTRY
  drivers/irqchip: Use new macro ACPI_DECLARE_SUBTABLE_PROBE_ENTRY
  drivers/acpi: Remove function cast

 drivers/irqchip/irq-gic-v3.c |  2 +-
 drivers/irqchip/irq-gic.c    |  2 +-
 include/linux/acpi.h         | 23 +++++++++++++++++------
 include/linux/irqchip.h      |  5 +++--
 4 files changed, 22 insertions(+), 10 deletions(-)

--
2.20.1

[PATCH v5 1/3] drivers/acpi: 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 v5 2/3] 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

[PATCH v5 3/3] drivers/acpi: Remove function cast

[Oscar Carter]

Remove the function cast in the ACPI_DECLARE_PROBE_ENTRY macro to ensure
that the functions passed as a last parameter to this macro have the
right prototype.

This is an effort to enable -Wcast-function-type in the top-level Makefile
to support Control Flow Integrity builds.

Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Oscar Carter <oscar.carter@gmx.com>
---
 include/linux/acpi.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index cf74e044a570..1cda2d32e4c4 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1143,16 +1143,16 @@ struct acpi_probe_entry {
 	kernel_ulong_t driver_data;
 };

-#define ACPI_DECLARE_PROBE_ENTRY(table, name, table_id, subtable, valid, data, fn)	\
+#define ACPI_DECLARE_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)		\
-		 = {							\
+		__used __section(__##table##_acpi_probe_table) = {	\
 			.id = table_id,					\
 			.type = subtable,				\
 			.subtable_valid = valid,			\
-			.probe_table = (acpi_tbl_table_handler)fn,	\
-			.driver_data = data, 				\
-		   }
+			.probe_table = fn,				\
+			.driver_data = data,				\
+		}

 #define ACPI_DECLARE_SUBTABLE_PROBE_ENTRY(table, name, table_id,	\
 					  subtable, valid, data, fn)	\
--
2.20.1

Re: [PATCH v5 0/3] drivers/acpi: Remove function callback casts

[Marc Zyngier]

Hi Rafael,

On 2020-05-30 15:34, 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 in the acpi driver.
> 
> 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.
> 
> The third patch removes the function cast in the 
> ACPI_DECLARE_PROBE_ENTRY
> macro to ensure that the functions passed as a last parameter to this 
> macro
> have the right prototype. This macro is used only in another macro
> called "TIMER_ACPI_DECLARE". An this is used only in the file:
> 
> drivers/clocksource/arm_arch_timer.c
> 
> In this file, the function used in the last parameter of the
> TIMER_ACPI_DECLARE macro already has the right prototype. So there is 
> no
> need to modify its prototype.

I'd like to see this into 5.9. Can you please let me know if
you are OK with the acpi.h changes? I can queue it via the irqchip
tree.

Thanks,

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

Re: [PATCH v5 0/3] drivers/acpi: Remove function callback casts

[Rafael J. Wysocki]

Hi,

On Fri, Jun 26, 2020 at 3:07 PM Marc Zyngier <maz@kernel.org> wrote:
>
> Hi Rafael,
>
> On 2020-05-30 15:34, 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 in the acpi driver.
> >
> > 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.
> >
> > The third patch removes the function cast in the
> > ACPI_DECLARE_PROBE_ENTRY
> > macro to ensure that the functions passed as a last parameter to this
> > macro
> > have the right prototype. This macro is used only in another macro
> > called "TIMER_ACPI_DECLARE". An this is used only in the file:
> >
> > drivers/clocksource/arm_arch_timer.c
> >
> > In this file, the function used in the last parameter of the
> > TIMER_ACPI_DECLARE macro already has the right prototype. So there is
> > no
> > need to modify its prototype.
>
> I'd like to see this into 5.9. Can you please let me know if
> you are OK with the acpi.h changes?

Yes, I am.

> I can queue it via the irqchip tree.

Please do!  Also please feel free to add

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

to the patches.

Thanks!

Re: [PATCH v5 0/3] drivers/acpi: Remove function callback casts

[Marc Zyngier]

On Sat, 30 May 2020 16:34:27 +0200, 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 in the acpi driver.
> 
> 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.
> 
> [...]

Applied to irq/irqchip-5.9:

[1/3] drivers/acpi: Add new macro ACPI_DECLARE_SUBTABLE_PROBE_ENTRY
      commit: 89778093d38d547cd80f6097659d1cf1c2dd4d9d
[2/3] drivers/irqchip: Use new macro ACPI_DECLARE_SUBTABLE_PROBE_ENTRY
      commit: aba3c7ed3fcf74524b7072615028827d5e5750d7
[3/3] drivers/acpi: Remove function cast
      commit: 8ebf642f3d809b59f57d0d408189a2218294e269

Thanks,

	M.
-- 
Without deviation from the norm, progress is not possible.