ACPICA: Introduce ACPI_NONSTRING

ACPICA commit 878823ca20f1987cba0c9d4c1056be0d117ea4fe

In order to distinguish character arrays from C Strings (i.e. strings with
a terminating NUL character), add support for the "nonstring" attribute
provided by GCC. (A better name might be "ACPI_NONCSTRING", but that's
the attribute name, so stick to the existing naming convention.)

GCC 15's -Wunterminated-string-initialization will warn about truncation
of the NUL byte for string initializers unless the destination is marked
with "nonstring". Prepare for applying this attribute to the project.

Link: acpica/acpica@878823ca
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/1841930.VLH7GnMWUR@rjwysocki.net
Signed-off-by: Kees Cook <kees@kernel.org>
[ rjw: Pick up the tag from Kees ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: kees

include/acpi/actypes.h

@@ -1327,4 +1327,8 @@ typedef enum {
 #define ACPI_FLEX_ARRAY(TYPE, NAME)     TYPE NAME[0]
 #endif
 
+#ifndef ACPI_NONSTRING
+#define ACPI_NONSTRING		/* No terminating NUL character */
+#endif
+
 #endif				/* __ACTYPES_H__ */

include/acpi/platform/acgcc.h

@@ -72,4 +72,12 @@
                 TYPE NAME[];                    \
         }
 
+/*
+ * Explicitly mark strings that lack a terminating NUL character so
+ * that ACPICA can be built with -Wunterminated-string-initialization.
+ */
+#if __has_attribute(__nonstring__)
+#define ACPI_NONSTRING __attribute__((__nonstring__))
+#endif
+
 #endif				/* __ACGCC_H__ */