diff --git a/spm/common/sp_helpers.h b/spm/common/sp_helpers.h
index 6fe8ec0..ef60221 100644
--- a/spm/common/sp_helpers.h
+++ b/spm/common/sp_helpers.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2021, Arm Limited. All rights reserved.
+ * Copyright (c) 2018-2022, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -10,6 +10,10 @@
 #include <stdint.h>
 #include <tftf_lib.h>
 #include <spm_common.h>
+#include <spinlock.h>
+
+/* Currently, Hafnium/SPM supports only 64 virtual interrupt IDs. */
+#define NUM_VINT_ID	64
 
 typedef struct {
 	u_register_t fid;
@@ -62,4 +66,16 @@
 /* Sleep for at least 'ms' milliseconds. */
 void sp_sleep(uint32_t ms);
 
+void sp_handler_spin_lock_init(void);
+
+/* Handler invoked at the tail end of interrupt processing by SP. */
+extern void (*sp_interrupt_tail_end_handler[NUM_VINT_ID])(void);
+
+/* Register the handler. */
+void sp_register_interrupt_tail_end_handler(void (*handler)(void),
+						uint32_t interrupt_id);
+
+/* Un-register the handler. */
+void sp_unregister_interrupt_tail_end_handler(uint32_t interrupt_id);
+
 #endif /* SP_HELPERS_H */