Merge pull request #1284 from jeenu-arm/tspd-ehf
TSPD and EHF
diff --git a/bl31/ehf.c b/bl31/ehf.c
index 39ee635..8673564 100644
--- a/bl31/ehf.c
+++ b/bl31/ehf.c
@@ -9,6 +9,8 @@
*/
#include <assert.h>
+#include <context.h>
+#include <context_mgmt.h>
#include <cpu_data.h>
#include <debug.h>
#include <ehf.h>
@@ -308,15 +310,17 @@
/*
* Program Priority Mask to the original Non-secure priority such that
* Non-secure interrupts may preempt Secure execution, viz. during Yielding SMC
- * calls.
+ * calls. The 'preempt_ret_code' parameter indicates the Yielding SMC's return
+ * value in case the call was preempted.
*
* This API is expected to be invoked before delegating a yielding SMC to Secure
* EL1. I.e. within the window of secure execution after Non-secure context is
* saved (after entry into EL3) and Secure context is restored (before entering
* Secure EL1).
*/
-void ehf_allow_ns_preemption(void)
+void ehf_allow_ns_preemption(uint64_t preempt_ret_code)
{
+ cpu_context_t *ns_ctx;
unsigned int old_pmr __unused;
pe_exc_data_t *pe_data = this_cpu_data();
@@ -333,6 +337,15 @@
panic();
}
+ /*
+ * Program preempted return code to x0 right away so that, if the
+ * Yielding SMC was indeed preempted before a dispatcher gets a chance
+ * to populate it, the caller would find the correct return value.
+ */
+ ns_ctx = cm_get_context(NON_SECURE);
+ assert(ns_ctx);
+ write_ctx_reg(get_gpregs_ctx(ns_ctx), CTX_GPREG_X0, preempt_ret_code);
+
old_pmr = plat_ic_set_priority_mask(pe_data->ns_pri_mask);
EHF_LOG("Priority Mask: 0x%x => 0x%x\n", old_pmr, pe_data->ns_pri_mask);
diff --git a/include/bl31/ehf.h b/include/bl31/ehf.h
index be8c957..f963f8d 100644
--- a/include/bl31/ehf.h
+++ b/include/bl31/ehf.h
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -82,7 +82,7 @@
void ehf_activate_priority(unsigned int priority);
void ehf_deactivate_priority(unsigned int priority);
void ehf_register_priority_handler(unsigned int pri, ehf_handler_t handler);
-void ehf_allow_ns_preemption(void);
+void ehf_allow_ns_preemption(uint64_t preempt_ret_code);
unsigned int ehf_is_ns_preemption_allowed(void);
#endif /* __ASSEMBLY__ */
diff --git a/services/spd/tspd/tspd_main.c b/services/spd/tspd/tspd_main.c
index c564f8b..3d06e0b 100644
--- a/services/spd/tspd/tspd_main.c
+++ b/services/spd/tspd/tspd_main.c
@@ -549,9 +549,10 @@
* preempt Secure execution. However, for
* yielding SMCs, we want preemption to happen;
* so explicitly allow NS preemption in this
- * case.
+ * case, and supply the preemption return code
+ * for TSP.
*/
- ehf_allow_ns_preemption();
+ ehf_allow_ns_preemption(TSP_PREEMPTED);
#endif
}
@@ -662,9 +663,10 @@
#if EL3_EXCEPTION_HANDLING
/*
* Allow the resumed yielding SMC processing to be preempted by
- * Non-secure interrupts.
+ * Non-secure interrupts. Also, supply the preemption return
+ * code for TSP.
*/
- ehf_allow_ns_preemption();
+ ehf_allow_ns_preemption(TSP_PREEMPTED);
#endif
/* We just need to return to the preempted point in