runtime constants: add default dummy infrastructure
This adds the initial dummy support for 'runtime constants' for when
an architecture doesn't actually support an implementation of fixing
up said runtime constants.
This ends up being the fallback to just using the variables as regular
__ro_after_init variables, and changes the dcache d_hash() function to
use this model.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild
index b20fa25..052e5c98 100644
--- a/include/asm-generic/Kbuild
+++ b/include/asm-generic/Kbuild
@@ -46,6 +46,7 @@
mandatory-y += percpu.h
mandatory-y += pgalloc.h
mandatory-y += preempt.h
+mandatory-y += runtime-const.h
mandatory-y += rwonce.h
mandatory-y += sections.h
mandatory-y += serial.h
diff --git a/include/asm-generic/runtime-const.h b/include/asm-generic/runtime-const.h
new file mode 100644
index 0000000..6704994
--- /dev/null
+++ b/include/asm-generic/runtime-const.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_RUNTIME_CONST_H
+#define _ASM_RUNTIME_CONST_H
+
+/*
+ * This is the fallback for when the architecture doesn't
+ * support the runtime const operations.
+ *
+ * We just use the actual symbols as-is.
+ */
+#define runtime_const_ptr(sym) (sym)
+#define runtime_const_shift_right_32(val, sym) ((u32)(val)>>(sym))
+#define runtime_const_init(type,sym) do { } while (0)
+
+#endif
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 5703526..389a784 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -944,6 +944,14 @@
#define CON_INITCALL \
BOUNDED_SECTION_POST_LABEL(.con_initcall.init, __con_initcall, _start, _end)
+#define RUNTIME_NAME(t,x) runtime_##t##_##x
+
+#define RUNTIME_CONST(t,x) \
+ . = ALIGN(8); \
+ RUNTIME_NAME(t,x) : AT(ADDR(RUNTIME_NAME(t,x)) - LOAD_OFFSET) { \
+ *(RUNTIME_NAME(t,x)); \
+ }
+
/* Alignment must be consistent with (kunit_suite *) in include/kunit/test.h */
#define KUNIT_TABLE() \
. = ALIGN(8); \
