SPM: Allow preemption in non-blocking requests

Change-Id: I1fdc2285a3f6517a715ad6159322543fd5a37a37
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

3 files changed, 65 insertions, 8 deletions

diff --git a/services/std_svc/spm/spci.c b/services/std_svc/spm/spci.c
index 41b0b00c..5e4ff918 100644
--- a/services/std_svc/spm/spci.c
+++ b/services/std_svc/spm/spci.c
@@ -348,7 +348,7 @@ static uint64_t spci_service_request_blocking(void *handle,
 	}
 
 	/* Jump to the Secure Partition. */
-	rx0 = spm_sp_synchronous_entry(sp_ctx);
+	rx0 = spm_sp_synchronous_entry(sp_ctx, 0);
 
 	/* Verify returned value */
 	if (rx0 != SPRT_PUT_RESPONSE_AARCH64) {
@@ -454,8 +454,14 @@ static uint64_t spci_service_request_start(void *handle,
 	/* Save the Normal world context */
 	cm_el1_sysregs_context_save(NON_SECURE);
 
+	/*
+	 * This request is non-blocking and needs to be interruptible by
+	 * non-secure interrupts. Enable their routing to EL3 during the
+	 * processing of the Secure Partition's service on this core.
+	 */
+
 	/* Jump to the Secure Partition. */
-	uint64_t ret = spm_sp_synchronous_entry(sp_ctx);
+	uint64_t ret = spm_sp_synchronous_entry(sp_ctx, 1);
 
 	/* Verify returned values */
 	if (ret == SPRT_PUT_RESPONSE_AARCH64) {
@@ -480,7 +486,8 @@ static uint64_t spci_service_request_start(void *handle,
 			 */
 			panic();
 		}
-	} else if (ret != SPRT_YIELD_AARCH64) {
+	} else if ((ret != SPRT_YIELD_AARCH64) &&
+		   (ret != SPM_SECURE_PARTITION_PREEMPTED)) {
 		ERROR("SPM: %s: Unexpected x0 value 0x%llx\n", __func__, ret);
 		panic();
 	}
@@ -554,8 +561,14 @@ static uint64_t spci_service_request_resume(void *handle, u_register_t x1,
 	/* Save the Normal world context */
 	cm_el1_sysregs_context_save(NON_SECURE);
 
+	/*
+	 * This request is non-blocking and needs to be interruptible by
+	 * non-secure interrupts. Enable their routing to EL3 during the
+	 * processing of the Secure Partition's service on this core.
+	 */
+
 	/* Jump to the Secure Partition. */
-	uint64_t ret = spm_sp_synchronous_entry(sp_ctx);
+	uint64_t ret = spm_sp_synchronous_entry(sp_ctx, 1);
 
 	/* Verify returned values */
 	if (ret == SPRT_PUT_RESPONSE_AARCH64) {
@@ -580,7 +593,8 @@ static uint64_t spci_service_request_resume(void *handle, u_register_t x1,
 			 */
 			panic();
 		}
-	} else if (ret != SPRT_YIELD_AARCH64) {
+	} else if ((ret != SPRT_YIELD_AARCH64) &&
+		   (ret != SPM_SECURE_PARTITION_PREEMPTED)) {
 		ERROR("SPM: %s: Unexpected x0 value 0x%llx\n", __func__, ret);
 		panic();
 	}
diff --git a/services/std_svc/spm/spm_main.c b/services/std_svc/spm/spm_main.c
index 050c66cc..5d3cc1a3 100644
--- a/services/std_svc/spm/spm_main.c
+++ b/services/std_svc/spm/spm_main.c
@@ -11,6 +11,7 @@
 #include <debug.h>
 #include <ehf.h>
 #include <errno.h>
+#include <interrupt_mgmt.h>
 #include <platform.h>
 #include <runtime_svc.h>
 #include <smccc.h>
@@ -167,7 +168,7 @@ int sp_state_try_switch(sp_context_t *sp_ptr, sp_state_t from, sp_state_t to)
  * This function takes an SP context pointer and performs a synchronous entry
  * into it.
  ******************************************************************************/
-uint64_t spm_sp_synchronous_entry(sp_context_t *sp_ctx)
+uint64_t spm_sp_synchronous_entry(sp_context_t *sp_ctx, int can_preempt)
 {
 	uint64_t rc;
 	unsigned int linear_id = plat_my_core_pos();
@@ -186,6 +187,12 @@ uint64_t spm_sp_synchronous_entry(sp_context_t *sp_ctx)
 	tlbivmalle1();
 	dsbish();
 
+	if (can_preempt == 1) {
+		enable_intr_rm_local(INTR_TYPE_NS, SECURE);
+	} else {
+		disable_intr_rm_local(INTR_TYPE_NS, SECURE);
+	}
+
 	/* Enter Secure Partition */
 	rc = spm_secure_partition_enter(&sp_ctx->c_rt_ctx);
 
@@ -216,6 +223,20 @@ __dead2 void spm_sp_synchronous_exit(uint64_t rc)
 }
 
 /*******************************************************************************
+ * This function is the handler registered for Non secure interrupts by the SPM.
+ * It validates the interrupt and upon success arranges entry into the normal
+ * world for handling the interrupt.
+ ******************************************************************************/
+static uint64_t spm_ns_interrupt_handler(uint32_t id, uint32_t flags,
+					  void *handle, void *cookie)
+{
+	/* Check the security state when the exception was generated */
+	assert(get_interrupt_src_ss(flags) == SECURE);
+
+	spm_sp_synchronous_exit(SPM_SECURE_PARTITION_PREEMPTED);
+}
+
+/*******************************************************************************
  * Jump to each Secure Partition for the first time.
  ******************************************************************************/
 static int32_t spm_init(void)
@@ -235,7 +256,7 @@ static int32_t spm_init(void)
 
 		ctx->state = SP_STATE_RESET;
 
-		rc = spm_sp_synchronous_entry(ctx);
+		rc = spm_sp_synchronous_entry(ctx, 0);
 		if (rc != SPRT_YIELD_AARCH64) {
 			ERROR("Unexpected return value 0x%llx\n", rc);
 			panic();
@@ -258,10 +279,29 @@ int32_t spm_setup(void)
 	sp_context_t *ctx;
 	void *sp_base, *rd_base;
 	size_t sp_size, rd_size;
+	uint64_t flags = 0U;
 
 	/* Disable MMU at EL1 (initialized by BL2) */
 	disable_mmu_icache_el1();
 
+	/*
+	 * Non-blocking services can be interrupted by Non-secure interrupts.
+	 * Register an interrupt handler for NS interrupts when generated while
+	 * the CPU is in secure state. They are routed to EL3.
+	 */
+	set_interrupt_rm_flag(flags, SECURE);
+
+	uint64_t rc_int = register_interrupt_type_handler(INTR_TYPE_NS,
+				spm_ns_interrupt_handler, flags);
+	if (rc_int) {
+		ERROR("SPM: Failed to register NS interrupt handler with rc = %llx\n",
+		      rc_int);
+		panic();
+	}
+
+	/*
+	 * Setup all Secure Partitions.
+	 */
 	unsigned int i = 0U;
 
 	while (1) {
diff --git a/services/std_svc/spm/spm_private.h b/services/std_svc/spm/spm_private.h
index 7216003b..5414e834 100644
--- a/services/std_svc/spm/spm_private.h
+++ b/services/std_svc/spm/spm_private.h
@@ -29,6 +29,9 @@
 #define SP_C_RT_CTX_SIZE	0x60
 #define SP_C_RT_CTX_ENTRIES	(SP_C_RT_CTX_SIZE >> DWORD_SHIFT)
 
+/* Value returned by spm_sp_synchronous_entry() when a partition is preempted */
+#define SPM_SECURE_PARTITION_PREEMPTED	U(0x1234)
+
 #ifndef __ASSEMBLY__
 
 #include <spinlock.h>
@@ -68,7 +71,7 @@ typedef struct sp_context {
 } sp_context_t;
 
 /* Functions used to enter/exit a Secure Partition synchronously */
-uint64_t spm_sp_synchronous_entry(sp_context_t *sp_ctx);
+uint64_t spm_sp_synchronous_entry(sp_context_t *sp_ctx, int can_preempt);
 __dead2 void spm_sp_synchronous_exit(uint64_t rc);
 
 /* Assembly helpers */