[PATCH] ACPICA: Use uintptr_t and offsetof() in Linux kernel builds

From: Rafael J. Wysocki
Date: Tue Jan 11 2022 - 10:55:31 EST


From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

To avoid "performing pointer subtraction with a null pointer has
undefined behavior" compiler warnings, use uintptr_t and offsetof()
that are always available during Linux kernel builds to define
acpi_uintptr_t and the ACPI_TO_INTEGER() and ACPI_OFFSET() macros.

Based on earlier proposal from Arnd Bergmann.

Link: https://lore.kernel.org/linux-acpi/20210927121338.938994-1-arnd@xxxxxxxxxx
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
include/acpi/actypes.h | 4 ++++
include/acpi/platform/aclinux.h | 5 +++++
2 files changed, 9 insertions(+)

Index: linux-pm/include/acpi/platform/aclinux.h
===================================================================
--- linux-pm.orig/include/acpi/platform/aclinux.h
+++ linux-pm/include/acpi/platform/aclinux.h
@@ -114,6 +114,11 @@
#define acpi_raw_spinlock raw_spinlock_t *
#define acpi_cpu_flags unsigned long

+#define acpi_uintptr_t uintptr_t
+
+#define ACPI_TO_INTEGER(p) ((uintptr_t)(p))
+#define ACPI_OFFSET(d, f) offsetof(d, f)
+
/* Use native linux version of acpi_os_allocate_zeroed */

#define USE_NATIVE_ALLOCATE_ZEROED
Index: linux-pm/include/acpi/actypes.h
===================================================================
--- linux-pm.orig/include/acpi/actypes.h
+++ linux-pm/include/acpi/actypes.h
@@ -507,8 +507,12 @@ typedef u64 acpi_integer;
/* Pointer/Integer type conversions */

#define ACPI_TO_POINTER(i) ACPI_CAST_PTR (void, (acpi_size) (i))
+#ifndef ACPI_TO_INTEGER
#define ACPI_TO_INTEGER(p) ACPI_PTR_DIFF (p, (void *) 0)
+#endif
+#ifndef ACPI_OFFSET
#define ACPI_OFFSET(d, f) ACPI_PTR_DIFF (&(((d *) 0)->f), (void *) 0)
+#endif
#define ACPI_PTR_TO_PHYSADDR(i) ACPI_TO_INTEGER(i)

/* Optimizations for 4-character (32-bit) acpi_name manipulation */