1 files changed, 54 insertions, 0 deletions
diff --git a/include/linux/kho/abi/block.h b/include/linux/kho/abi/block.h
new file mode 100644
index 000000000000..d06d64b963be
--- /dev/null
+++ b/include/linux/kho/abi/block.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2026, Google LLC.
+ * Pasha Tatashin <pasha.tatashin@soleen.com>
+ */
+
+/**
+ * DOC: KHO Serialization Blocks ABI
+ *
+ * Subsystems using the KHO Serialization Blocks framework rely on the stable
+ * Application Binary Interface defined below to pass serialized state from a
+ * pre-update kernel to a post-update kernel.
+ *
+ * This interface is a contract. Any modification to the structure fields,
+ * compatible strings, or the layout of the `__packed` serialization
+ * structures defined here constitutes a breaking change. Such changes require
+ * incrementing the version number in the `KHO_FDT_COMPATIBLE` string to
+ * prevent a new kernel from misinterpreting data from an old kernel.
+ *
+ * Changes are allowed provided the compatibility version is incremented;
+ * however, backward/forward compatibility is only guaranteed for kernels
+ * supporting the same ABI version.
+ */
+
+#ifndef _LINUX_KHO_ABI_BLOCK_H
+#define _LINUX_KHO_ABI_BLOCK_H
+
+#include <asm/page.h>
+#include <linux/types.h>
+
+/**
+ * KHO_BLOCK_SIZE - The size of each serialization block.
+ *
+ * This is defined as PAGE_SIZE. PAGE_SIZE is ABI compliant because live
+ * update between kernels with different page sizes is not supported by KHO.
+ */
+#define KHO_BLOCK_SIZE			PAGE_SIZE
+
+/**
+ * struct kho_block_header_ser - Header for the serialized data block.
+ * @next:  Physical address of the next struct kho_block_header_ser.
+ * @count: The number of entries that immediately follow this header in the
+ *         memory block.
+ *
+ * This structure is located at the beginning of a block of physical memory
+ * preserved across a kexec. It provides the necessary metadata to interpret
+ * the array of entries that follow.
+ */
+struct kho_block_header_ser {
+	u64 next;
+	u64 count;
+} __packed;
+
+#endif /* _LINUX_KHO_ABI_BLOCK_H */