drivers/acpi: Add new macro ACPI_DECLARE_SUBTABLE_PROBE_ENTRY

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>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20200530143430.5203-2-oscar.carter@gmx.com

diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index d661cd0..cf74e04 100644 (file)
--- 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