memblock: always include KHO headers

In a coming commit, memblock will start using kho_scratch_overlap()
without a compile guard. The compile guard for the function is in
kexec_handover.h and provides a stub when CONFIG_KEXEC_HANDOVER is
disabled.

Since in memblock the call will exist unconditionally, always include
the KHO headers.

Including these headers unconditionally breaks memblock test
compilation. Add stubs to fix that.

Signed-off-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Link: https://patch.msgid.link/20260801084833.1897543-20-pratyush@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

mm/memblock.c

@@ -19,11 +19,9 @@
 #include <linux/mutex.h>
 #include <linux/string_helpers.h>
 
-#ifdef CONFIG_KEXEC_HANDOVER
 #include <linux/libfdt.h>
 #include <linux/kexec_handover.h>
 #include <linux/kho/abi/memblock.h>
-#endif /* CONFIG_KEXEC_HANDOVER */
 
 #include <asm/sections.h>
 #include <linux/io.h>

tools/testing/memblock/linux/kexec_handover.h

@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef LINUX_KEXEC_HANDOVER_H
+#define LINUX_KEXEC_HANDOVER_H
+
+/*
+ * Header stub to avoid test build breakage; we don't need to actually implement
+ * any KHO functions as they are not used in the tests.
+ */
+#endif /* LINUX_KEXEC_HANDOVER_H */

tools/testing/memblock/linux/kho/abi/memblock.h

@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _LINUX_KHO_ABI_MEMBLOCK_H
+#define _LINUX_KHO_ABI_MEMBLOCK_H
+
+/*
+ * Header stub to avoid test build breakage; we don't need to actually define
+ * any ABI as they are not used in the tests.
+ */
+#endif /* _LINUX_KHO_ABI_MEMBLOCK_H */

tools/testing/memblock/linux/libfdt.h

@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _INCLUDE_LIBFDT_H_
+#define _INCLUDE_LIBFDT_H_
+
+/*
+ * Header stub to avoid test build breakage; we don't need to actually implement
+ * any FDT functions as they are not used in the tests.
+ */
+#endif /* _INCLUDE_LIBFDT_H_ */