diff --git a/services/spd/tspd/tspd_common.c b/services/spd/tspd/tspd_common.c
index d3fe5dd..2d0b08b 100644
--- a/services/spd/tspd/tspd_common.c
+++ b/services/spd/tspd/tspd_common.c
@@ -85,7 +85,14 @@
 	write_ctx_reg(el1_state, CTX_SCTLR_EL1, sctlr);
 
 	/* Set this context as ready to be initialised i.e OFF */
-	tsp_ctx->state = TSP_STATE_OFF;
+	set_tsp_pstate(tsp_ctx->state, TSP_PSTATE_OFF);
+
+	/*
+	 * This context has not been used yet. It will become valid
+	 * when the TSP is interrupted and wants the TSPD to preserve
+	 * the context.
+	 */
+	clr_std_smc_active_flag(tsp_ctx->state);
 
 	/* Associate this context with the cpu specified */
 	tsp_ctx->mpidr = mpidr;
diff --git a/services/spd/tspd/tspd_main.c b/services/spd/tspd/tspd_main.c
index 21ff7ff..f192d34 100644
--- a/services/spd/tspd/tspd_main.c
+++ b/services/spd/tspd/tspd_main.c
@@ -142,7 +142,7 @@
 	rc = tspd_synchronous_sp_entry(tsp_ctx);
 	assert(rc != 0);
 	if (rc) {
-		tsp_ctx->state = TSP_STATE_ON;
+		set_tsp_pstate(tsp_ctx->state, TSP_PSTATE_ON);
 
 		/*
 		 * TSP has been successfully initialized. Register power
diff --git a/services/spd/tspd/tspd_pm.c b/services/spd/tspd/tspd_pm.c
index 2447d9e..75b4b30 100644
--- a/services/spd/tspd/tspd_pm.c
+++ b/services/spd/tspd/tspd_pm.c
@@ -56,7 +56,7 @@
 	tsp_context_t *tsp_ctx = &tspd_sp_context[linear_id];
 
 	assert(tsp_entry_info);
-	assert(tsp_ctx->state == TSP_STATE_ON);
+	assert(get_tsp_pstate(tsp_ctx->state) == TSP_PSTATE_ON);
 
 	/* Program the entry point and enter the TSP */
 	cm_set_el3_elr(SECURE, (uint64_t) tsp_entry_info->cpu_off_entry);
@@ -73,7 +73,7 @@
 	 * Reset TSP's context for a fresh start when this cpu is turned on
 	 * subsequently.
 	 */
-	 tsp_ctx->state = TSP_STATE_OFF;
+	set_tsp_pstate(tsp_ctx->state, TSP_PSTATE_OFF);
 
 	 return 0;
 }
@@ -90,7 +90,7 @@
 	tsp_context_t *tsp_ctx = &tspd_sp_context[linear_id];
 
 	assert(tsp_entry_info);
-	assert(tsp_ctx->state == TSP_STATE_ON);
+	assert(get_tsp_pstate(tsp_ctx->state) == TSP_PSTATE_ON);
 
 	/* Program the entry point, power_state parameter and enter the TSP */
 	write_ctx_reg(get_gpregs_ctx(&tsp_ctx->cpu_ctx),
@@ -107,7 +107,7 @@
 		panic();
 
 	/* Update its context to reflect the state the TSP is in */
-	tsp_ctx->state = TSP_STATE_SUSPEND;
+	set_tsp_pstate(tsp_ctx->state, TSP_PSTATE_SUSPEND);
 }
 
 /*******************************************************************************
@@ -124,7 +124,7 @@
 	tsp_context_t *tsp_ctx = &tspd_sp_context[linear_id];
 
 	assert(tsp_entry_info);
-	assert(tsp_ctx->state == TSP_STATE_OFF);
+	assert(get_tsp_pstate(tsp_ctx->state) == TSP_PSTATE_OFF);
 
 	/* Initialise this cpu's secure context */
 	tspd_init_secure_context((uint64_t) tsp_entry_info->cpu_on_entry,
@@ -143,7 +143,7 @@
 		panic();
 
 	/* Update its context to reflect the state the SP is in */
-	tsp_ctx->state = TSP_STATE_ON;
+	set_tsp_pstate(tsp_ctx->state, TSP_PSTATE_ON);
 }
 
 /*******************************************************************************
@@ -159,7 +159,7 @@
 	tsp_context_t *tsp_ctx = &tspd_sp_context[linear_id];
 
 	assert(tsp_entry_info);
-	assert(tsp_ctx->state == TSP_STATE_SUSPEND);
+	assert(get_tsp_pstate(tsp_ctx->state) == TSP_PSTATE_SUSPEND);
 
 	/* Program the entry point, suspend_level and enter the SP */
 	write_ctx_reg(get_gpregs_ctx(&tsp_ctx->cpu_ctx),
@@ -176,7 +176,7 @@
 		panic();
 
 	/* Update its context to reflect the state the SP is in */
-	tsp_ctx->state = TSP_STATE_ON;
+	set_tsp_pstate(tsp_ctx->state, TSP_PSTATE_ON);
 }
 
 /*******************************************************************************
diff --git a/services/spd/tspd/tspd_private.h b/services/spd/tspd/tspd_private.h
index 81484e1..bb0afcd 100644
--- a/services/spd/tspd/tspd_private.h
+++ b/services/spd/tspd/tspd_private.h
@@ -38,10 +38,41 @@
 
 /*******************************************************************************
  * Secure Payload PM state information e.g. SP is suspended, uninitialised etc
+ * and macros to access the state information in the per-cpu 'state' flags
  ******************************************************************************/
-#define TSP_STATE_OFF		0
-#define TSP_STATE_ON		1
-#define TSP_STATE_SUSPEND	2
+#define TSP_PSTATE_OFF		0
+#define TSP_PSTATE_ON		1
+#define TSP_PSTATE_SUSPEND	2
+#define TSP_PSTATE_SHIFT	0
+#define TSP_PSTATE_MASK	0x3
+#define get_tsp_pstate(state)	((state >> TSP_PSTATE_SHIFT) & TSP_PSTATE_MASK)
+#define clr_tsp_pstate(state)	(state &= ~(TSP_PSTATE_MASK \
+					    << TSP_PSTATE_SHIFT))
+#define set_tsp_pstate(st, pst)	do {					       \
+					clr_tsp_pstate(st);		       \
+					st |= (pst & TSP_PSTATE_MASK) <<       \
+						TSP_PSTATE_SHIFT;	       \
+				} while (0);
+
+
+/*
+ * This flag is used by the TSPD to determine if the TSP is servicing a standard
+ * SMC request prior to programming the next entry into the TSP e.g. if TSP
+ * execution is preempted by a non-secure interrupt and handed control to the
+ * normal world. If another request which is distinct from what the TSP was
+ * previously doing arrives, then this flag will be help the TSPD to either
+ * reject the new request or service it while ensuring that the previous context
+ * is not corrupted.
+ */
+#define STD_SMC_ACTIVE_FLAG_SHIFT	2
+#define STD_SMC_ACTIVE_FLAG_MASK	1
+#define get_std_smc_active_flag(state)	((state >> STD_SMC_ACTIVE_FLAG_SHIFT) \
+					 & STD_SMC_ACTIVE_FLAG_MASK)
+#define set_std_smc_active_flag(state)	(state |=                             \
+					 1 << STD_SMC_ACTIVE_FLAG_SHIFT)
+#define clr_std_smc_active_flag(state)	(state &=                             \
+					 ~(STD_SMC_ACTIVE_FLAG_MASK           \
+					   << STD_SMC_ACTIVE_FLAG_SHIFT))
 
 /*******************************************************************************
  * Secure Payload execution state information i.e. aarch32 or aarch64