[RFC PATCH 01/17] asm-generic: add registers.h with a pc_inside() helper

[Ahmad Fatoum <a.fatoum@barebox.org>]

The upcoming board info stage dispatch determines the stage it runs in
by checking which stage's memory region covers the program counter.

Add asm-generic/registers.h with pc_inside(), built on the get_pc() that
ARM, RISC-V and PowerPC provide, as the home for such register level
helpers.

Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
---
 include/asm-generic/registers.h | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 include/asm-generic/registers.h

diff --git a/include/asm-generic/registers.h b/include/asm-generic/registers.h
new file mode 100644
index 000000000000..8ce28f74e1db
--- /dev/null
+++ b/include/asm-generic/registers.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* SPDX-FileCopyrightText: 2026 Ahmad Fatoum */
+
+#ifndef __ASM_GENERIC_REGISTERS_H
+#define __ASM_GENERIC_REGISTERS_H
+
+#include <linux/compiler.h>
+#include <asm/common.h>
+
+/*
+ * pc_inside - check if the program counter is in [start, start + size)
+ *
+ * A single unsigned compare, so it also works for a region ending at the
+ * top of the address space.
+ */
+static __always_inline bool pc_inside(unsigned long start, unsigned long size)
+{
+	unsigned long pc = get_pc();
+
+	return pc - start < size;
+}
+
+#endif
-- 
2.47.3