Merge pull request #1152 from jeenu-arm/ehf-and-sdei

EHF and SDEI

bl31/bl31.mk

@@ -32,6 +32,20 @@ ifeq (${ENABLE_PMF}, 1)
 BL31_SOURCES		+=	lib/pmf/pmf_main.c
 endif
 
+ifeq (${EL3_EXCEPTION_HANDLING},1)
+BL31_SOURCES		+=	bl31/ehf.c
+endif
+
+ifeq (${SDEI_SUPPORT},1)
+ifeq (${EL3_EXCEPTION_HANDLING},0)
+  $(error EL3_EXCEPTION_HANDLING must be 1 for SDEI support)
+endif
+BL31_SOURCES		+=	services/std_svc/sdei/sdei_event.c	\
+				services/std_svc/sdei/sdei_intr_mgmt.c	\
+				services/std_svc/sdei/sdei_main.c	\
+				services/std_svc/sdei/sdei_state.c
+endif
+
 BL31_LINKERFILE		:=	bl31/bl31.ld.S
 
 # Flag used to indicate if Crash reporting via console should be included
@@ -41,4 +55,9 @@ CRASH_REPORTING		:=	$(DEBUG)
 endif
 
 $(eval $(call assert_boolean,CRASH_REPORTING))
+$(eval $(call assert_boolean,EL3_EXCEPTION_HANDLING))
+$(eval $(call assert_boolean,SDEI_SUPPORT))
+
 $(eval $(call add_define,CRASH_REPORTING))
+$(eval $(call add_define,EL3_EXCEPTION_HANDLING))
+$(eval $(call add_define,SDEI_SUPPORT))

bl31/bl31_main.c

@@ -12,6 +12,7 @@
 #include <console.h>
 #include <context_mgmt.h>
 #include <debug.h>
+#include <ehf.h>
 #include <platform.h>
 #include <pmf.h>
 #include <runtime_instr.h>
@@ -79,6 +80,11 @@ void bl31_main(void)
 	/* Initialise helper libraries */
 	bl31_lib_init();
 
+#if EL3_EXCEPTION_HANDLING
+	INFO("BL31: Initialising Exception Handling Framework\n");
+	ehf_init();
+#endif
+
 	/* Initialize the runtime services e.g. psci. */
 	INFO("BL31: Initializing runtime services\n");
 	runtime_svc_init();

bl31/ehf.c

+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+/*
+ * Exception handlers at EL3, their priority levels, and management.
+ */
+
+#include <assert.h>
+#include <cpu_data.h>
+#include <debug.h>
+#include <ehf.h>
+#include <gic_common.h>
+#include <interrupt_mgmt.h>
+#include <platform.h>
+#include <pubsub_events.h>
+
+/* Output EHF logs as verbose */
+#define EHF_LOG(...)	VERBOSE("EHF: " __VA_ARGS__)
+
+#define EHF_INVALID_IDX	(-1)
+
+/* For a valid handler, return the actual function pointer; otherwise, 0. */
+#define RAW_HANDLER(h) \
+	((ehf_handler_t) ((h & _EHF_PRI_VALID) ? (h & ~_EHF_PRI_VALID) : 0))
+
+#define PRI_BIT(idx)	(((ehf_pri_bits_t) 1) << idx)
+
+/*
+ * Convert index into secure priority using the platform-defined priority bits
+ * field.
+ */
+#define IDX_TO_PRI(idx) \
+	((idx << (7 - exception_data.pri_bits)) & 0x7f)
+
+/* Check whether a given index is valid */
+#define IS_IDX_VALID(idx) \
+	((exception_data.ehf_priorities[idx].ehf_handler & _EHF_PRI_VALID) != 0)
+
+/* Returns whether given priority is in secure priority range */
+#define IS_PRI_SECURE(pri)	((pri & 0x80) == 0)
+
+/* To be defined by the platform */
+extern const ehf_priorities_t exception_data;
+
+/* Translate priority to the index in the priority array */
+static int pri_to_idx(unsigned int priority)
+{
+	int idx;
+
+	idx = EHF_PRI_TO_IDX(priority, exception_data.pri_bits);
+	assert((idx >= 0) && (idx < exception_data.num_priorities));
+	assert(IS_IDX_VALID(idx));
+
+	return idx;
+}
+
+/* Return whether there are outstanding priority activation */
+static int has_valid_pri_activations(pe_exc_data_t *pe_data)
+{
+	return pe_data->active_pri_bits != 0;
+}
+
+static pe_exc_data_t *this_cpu_data(void)
+{
+	return &get_cpu_data(ehf_data);
+}
+
+/*
+ * Return the current priority index of this CPU. If no priority is active,
+ * return EHF_INVALID_IDX.
+ */
+static int get_pe_highest_active_idx(pe_exc_data_t *pe_data)
+{
+	if (!has_valid_pri_activations(pe_data))
+		return EHF_INVALID_IDX;
+
+	/* Current priority is the right-most bit */
+	return __builtin_ctz(pe_data->active_pri_bits);
+}
+
+/*
+ * Mark priority active by setting the corresponding bit in active_pri_bits and
+ * programming the priority mask.
+ *
+ * This API is to be used as part of delegating to lower ELs other than for
+ * interrupts; e.g. while handling synchronous exceptions.
+ *
+ * This API is expected to be invoked before restoring context (Secure or
+ * Non-secure) in preparation for the respective dispatch.
+ */
+void ehf_activate_priority(unsigned int priority)
+{
+	int idx, cur_pri_idx;
+	unsigned int old_mask, run_pri;
+	pe_exc_data_t *pe_data = this_cpu_data();
+
+	/*
+	 * Query interrupt controller for the running priority, or idle priority
+	 * if no interrupts are being handled. The requested priority must be
+	 * less (higher priority) than the active running priority.
+	 */
+	run_pri = plat_ic_get_running_priority();
+	if (priority >= run_pri) {
+		ERROR("Running priority higher (0x%x) than requested (0x%x)\n",
+				run_pri, priority);
+		panic();
+	}
+
+	/*
+	 * If there were priority activations already, the requested priority
+	 * must be less (higher priority) than the current highest priority
+	 * activation so far.
+	 */
+	cur_pri_idx = get_pe_highest_active_idx(pe_data);
+	idx = pri_to_idx(priority);
+	if ((cur_pri_idx != EHF_INVALID_IDX) && (idx >= cur_pri_idx)) {
+		ERROR("Activation priority mismatch: req=0x%x current=0x%x\n",
+				priority, IDX_TO_PRI(cur_pri_idx));
+		panic();
+	}
+
+	/* Set the bit corresponding to the requested priority */
+	pe_data->active_pri_bits |= PRI_BIT(idx);
+
+	/*
+	 * Program priority mask for the activated level. Check that the new
+	 * priority mask is setting a higher priority level than the existing
+	 * mask.
+	 */
+	old_mask = plat_ic_set_priority_mask(priority);
+	if (priority >= old_mask) {
+		ERROR("Requested priority (0x%x) lower than Priority Mask (0x%x)\n",
+				priority, old_mask);
+		panic();
+	}
+
+	/*
+	 * If this is the first activation, save the priority mask. This will be
+	 * restored after the last deactivation.
+	 */
+	if (cur_pri_idx == EHF_INVALID_IDX)
+		pe_data->init_pri_mask = old_mask;
+
+	EHF_LOG("activate prio=%d\n", get_pe_highest_active_idx(pe_data));
+}
+
+/*
+ * Mark priority inactive by clearing the corresponding bit in active_pri_bits,
+ * and programming the priority mask.
+ *
+ * This API is expected to be used as part of delegating to to lower ELs other
+ * than for interrupts; e.g. while handling synchronous exceptions.
+ *
+ * This API is expected to be invoked after saving context (Secure or
+ * Non-secure), having concluded the respective dispatch.
+ */
+void ehf_deactivate_priority(unsigned int priority)
+{
+	int idx, cur_pri_idx;
+	pe_exc_data_t *pe_data = this_cpu_data();
+	unsigned int old_mask, run_pri;
+
+	/*
+	 * Query interrupt controller for the running priority, or idle priority
+	 * if no interrupts are being handled. The requested priority must be
+	 * less (higher priority) than the active running priority.
+	 */
+	run_pri = plat_ic_get_running_priority();
+	if (priority >= run_pri) {
+		ERROR("Running priority higher (0x%x) than requested (0x%x)\n",
+				run_pri, priority);
+		panic();
+	}
+
+	/*
+	 * Deactivation is allowed only when there are priority activations, and
+	 * the deactivation priority level must match the current activated
+	 * priority.
+	 */
+	cur_pri_idx = get_pe_highest_active_idx(pe_data);
+	idx = pri_to_idx(priority);
+	if ((cur_pri_idx == EHF_INVALID_IDX) || (idx != cur_pri_idx)) {
+		ERROR("Deactivation priority mismatch: req=0x%x current=0x%x\n",
+				priority, IDX_TO_PRI(cur_pri_idx));
+		panic();
+	}
+
+	/* Clear bit corresponding to highest priority */
+	pe_data->active_pri_bits &= (pe_data->active_pri_bits - 1);
+
+	/*
+	 * Restore priority mask corresponding to the next priority, or the
+	 * one stashed earlier if there are no more to deactivate.
+	 */
+	idx = get_pe_highest_active_idx(pe_data);
+	if (idx == EHF_INVALID_IDX)
+		old_mask = plat_ic_set_priority_mask(pe_data->init_pri_mask);
+	else
+		old_mask = plat_ic_set_priority_mask(priority);
+
+	if (old_mask >= priority) {
+		ERROR("Deactivation priority (0x%x) lower than Priority Mask (0x%x)\n",
+				priority, old_mask);
+		panic();
+	}
+
+	EHF_LOG("deactivate prio=%d\n", get_pe_highest_active_idx(pe_data));
+}
+
+/*
+ * After leaving Non-secure world, stash current Non-secure Priority Mask, and
+ * set Priority Mask to the highest Non-secure priority so that Non-secure
+ * interrupts cannot preempt Secure execution.
+ *
+ * If the current running priority is in the secure range, or if there are
+ * outstanding priority activations, this function does nothing.
+ *
+ * This function subscribes to the 'cm_exited_normal_world' event published by
+ * the Context Management Library.
+ */
+static void *ehf_exited_normal_world(const void *arg)
+{
+	unsigned int run_pri;
+	pe_exc_data_t *pe_data = this_cpu_data();
+
+	/* If the running priority is in the secure range, do nothing */
+	run_pri = plat_ic_get_running_priority();
+	if (IS_PRI_SECURE(run_pri))
+		return 0;
+
+	/* Do nothing if there are explicit activations */
+	if (has_valid_pri_activations(pe_data))
+		return 0;
+
+	assert(pe_data->ns_pri_mask == 0);
+
+	pe_data->ns_pri_mask =
+		plat_ic_set_priority_mask(GIC_HIGHEST_NS_PRIORITY);
+
+	/* The previous Priority Mask is not expected to be in secure range */
+	if (IS_PRI_SECURE(pe_data->ns_pri_mask)) {
+		ERROR("Priority Mask (0x%x) already in secure range\n",
+				pe_data->ns_pri_mask);
+		panic();
+	}
+
+	EHF_LOG("Priority Mask: 0x%x => 0x%x\n", pe_data->ns_pri_mask,
+			GIC_HIGHEST_NS_PRIORITY);
+
+	return 0;
+}
+
+/*
+ * Conclude Secure execution and prepare for return to Non-secure world. Restore
+ * the Non-secure Priority Mask previously stashed upon leaving Non-secure
+ * world.
+ *
+ * If there the current running priority is in the secure range, or if there are
+ * outstanding priority activations, this function does nothing.
+ *
+ * This function subscribes to the 'cm_entering_normal_world' event published by
+ * the Context Management Library.
+ */
+static void *ehf_entering_normal_world(const void *arg)
+{
+	unsigned int old_pmr, run_pri;
+	pe_exc_data_t *pe_data = this_cpu_data();
+
+	/* If the running priority is in the secure range, do nothing */
+	run_pri = plat_ic_get_running_priority();
+	if (IS_PRI_SECURE(run_pri))
+		return 0;
+
+	/*
+	 * If there are explicit activations, do nothing. The Priority Mask will
+	 * be restored upon the last deactivation.
+	 */
+	if (has_valid_pri_activations(pe_data))
+		return 0;
+
+	/* Do nothing if we don't have a valid Priority Mask to restore */
+	if (pe_data->ns_pri_mask == 0)
+		return 0;
+
+	old_pmr = plat_ic_set_priority_mask(pe_data->ns_pri_mask);
+
+	/*
+	 * When exiting secure world, the current Priority Mask must be
+	 * GIC_HIGHEST_NS_PRIORITY (as set during entry), or the Non-secure
+	 * priority mask set upon calling ehf_allow_ns_preemption()
+	 */
+	if ((old_pmr != GIC_HIGHEST_NS_PRIORITY) &&
+			(old_pmr != pe_data->ns_pri_mask)) {
+		ERROR("Invalid Priority Mask (0x%x) restored\n", old_pmr);
+		panic();
+	}
+
+	EHF_LOG("Priority Mask: 0x%x => 0x%x\n", old_pmr, pe_data->ns_pri_mask);
+
+	pe_data->ns_pri_mask = 0;
+
+	return 0;
+}
+
+/*
+ * Program Priority Mask to the original Non-secure priority such that
+ * Non-secure interrupts may preempt Secure execution, viz. during Yielding SMC
+ * calls.
+ *
+ * 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)
+{
+	unsigned int old_pmr __unused;
+	pe_exc_data_t *pe_data = this_cpu_data();
+
+	/*
+	 * We should have been notified earlier of entering secure world, and
+	 * therefore have stashed the Non-secure priority mask.
+	 */
+	assert(pe_data->ns_pri_mask != 0);
+
+	/* Make sure no priority levels are active when requesting this */
+	if (has_valid_pri_activations(pe_data)) {
+		ERROR("PE %lx has priority activations: 0x%x\n",
+				read_mpidr_el1(), pe_data->active_pri_bits);
+		panic();
+	}
+
+	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);
+
+	pe_data->ns_pri_mask = 0;
+}
+
+/*
+ * Return whether Secure execution has explicitly allowed Non-secure interrupts
+ * to preempt itself, viz. during Yielding SMC calls.
+ */
+unsigned int ehf_is_ns_preemption_allowed(void)
+{
+	unsigned int run_pri;
+	pe_exc_data_t *pe_data = this_cpu_data();
+
+	/* If running priority is in secure range, return false */
+	run_pri = plat_ic_get_running_priority();
+	if (IS_PRI_SECURE(run_pri))
+		return 0;
+
+	/*
+	 * If Non-secure preemption was permitted by calling
+	 * ehf_allow_ns_preemption() earlier:
+	 *
+	 * - There wouldn't have been priority activations;
+	 * - We would have cleared the stashed the Non-secure Priority Mask.
+	 */
+	if (has_valid_pri_activations(pe_data))
+		return 0;
+	if (pe_data->ns_pri_mask != 0)
+		return 0;
+
+	return 1;
+}
+
+/*
+ * Top-level EL3 interrupt handler.
+ */
+static uint64_t ehf_el3_interrupt_handler(uint32_t id, uint32_t flags,
+		void *handle, void *cookie)
+{
+	int pri, idx, intr, intr_raw, ret = 0;
+	ehf_handler_t handler;
+
+	/*
+	 * Top-level interrupt type handler from Interrupt Management Framework
+	 * doesn't acknowledge the interrupt; so the interrupt ID must be
+	 * invalid.
+	 */
+	assert(id == INTR_ID_UNAVAILABLE);
+
+	/*
+	 * Acknowledge interrupt. Proceed with handling only for valid interrupt
+	 * IDs. This situation may arise because of Interrupt Management
+	 * Framework identifying an EL3 interrupt, but before it's been
+	 * acknowledged here, the interrupt was either deasserted, or there was
+	 * a higher-priority interrupt of another type.
+	 */
+	intr_raw = plat_ic_acknowledge_interrupt();
+	intr = plat_ic_get_interrupt_id(intr_raw);
+	if (intr == INTR_ID_UNAVAILABLE)
+		return 0;
+
+	/* Having acknowledged the interrupt, get the running priority */
+	pri = plat_ic_get_running_priority();
+
+	/* Check EL3 interrupt priority is in secure range */
+	assert(IS_PRI_SECURE(pri));
+
+	/*
+	 * Translate the priority to a descriptor index. We do this by masking
+	 * and shifting the running priority value (platform-supplied).
+	 */
+	idx = pri_to_idx(pri);
+
+	/* Validate priority */
+	assert(pri == IDX_TO_PRI(idx));
+
+	handler = RAW_HANDLER(exception_data.ehf_priorities[idx].ehf_handler);
+	if (!handler) {
+		ERROR("No EL3 exception handler for priority 0x%x\n",
+				IDX_TO_PRI(idx));
+		panic();
+	}
+
+	/*
+	 * Call registered handler. Pass the raw interrupt value to registered
+	 * handlers.
+	 */
+	ret = handler(intr_raw, flags, handle, cookie);
+
+	return ret;
+}
+
+/*
+ * Initialize the EL3 exception handling.
+ */
+void ehf_init(void)
+{
+	unsigned int flags = 0;
+	int ret __unused;
+
+	/* Ensure EL3 interrupts are supported */
+	assert(plat_ic_has_interrupt_type(INTR_TYPE_EL3));
+
+	/*
+	 * Make sure that priority water mark has enough bits to represent the
+	 * whole priority array.
+	 */
+	assert(exception_data.num_priorities <= (sizeof(ehf_pri_bits_t) * 8));
+
+	assert(exception_data.ehf_priorities);
+
+	/*
+	 * Bit 7 of GIC priority must be 0 for secure interrupts. This means
+	 * platforms must use at least 1 of the remaining 7 bits.
+	 */
+	assert((exception_data.pri_bits >= 1) || (exception_data.pri_bits < 8));
+
+	/* Route EL3 interrupts when in Secure and Non-secure. */
+	set_interrupt_rm_flag(flags, NON_SECURE);
+	set_interrupt_rm_flag(flags, SECURE);
+
+	/* Register handler for EL3 interrupts */
+	ret = register_interrupt_type_handler(INTR_TYPE_EL3,
+			ehf_el3_interrupt_handler, flags);
+	assert(ret == 0);
+}
+
+/*
+ * Register a handler at the supplied priority. Registration is allowed only if
+ * a handler hasn't been registered before, or one wasn't provided at build
+ * time. The priority for which the handler is being registered must also accord
+ * with the platform-supplied data.
+ */
+void ehf_register_priority_handler(unsigned int pri, ehf_handler_t handler)
+{
+	int idx;
+
+	/* Sanity check for handler */
+	assert(handler != NULL);
+
+	/* Handler ought to be 4-byte aligned */
+	assert((((uintptr_t) handler) & 3) == 0);
+
+	/* Ensure we register for valid priority */
+	idx = pri_to_idx(pri);
+	assert(idx < exception_data.num_priorities);
+	assert(IDX_TO_PRI(idx) == pri);
+
+	/* Return failure if a handler was already registered */
+	if (exception_data.ehf_priorities[idx].ehf_handler != _EHF_NO_HANDLER) {
+		ERROR("Handler already registered for priority 0x%x\n", pri);
+		panic();
+	}
+
+	/*
+	 * Install handler, and retain the valid bit. We assume that the handler
+	 * is 4-byte aligned, which is usually the case.
+	 */
+	exception_data.ehf_priorities[idx].ehf_handler =
+		(((uintptr_t) handler) | _EHF_PRI_VALID);
+
+	EHF_LOG("register pri=0x%x handler=%p\n", pri, handler);
+}
+
+SUBSCRIBE_TO_EVENT(cm_entering_normal_world, ehf_entering_normal_world);
+SUBSCRIBE_TO_EVENT(cm_exited_normal_world, ehf_exited_normal_world);

docs/plantuml/plantuml_to_svg.sh

+#!/bin/bash
+
+# Convert all PlantUML files in this directory to SVG files. The plantuml_jar
+# environment variable must be set to the path to PlantUML JAR file.
+
+if [ -z "$plantuml_jar" ]; then
+	echo "Usage: plantuml_jar=/path/to/plantuml.jar $0 *.puml" >&2
+	exit 1
+fi
+
+java -jar "$plantuml_jar" -nometadata -tsvg "$@"
+
+# vim:set noet sts=8 tw=80:

docs/plantuml/sdei_explicit_dispatch.puml

+/'
+ ' Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ '
+ ' SPDX-License-Identifier: BSD-3-Clause
+ '/
+
+@startuml
+
+autonumber "<b>[#]</b>"
+participant "SDEI client" as EL2
+participant EL3
+participant SEL1
+
+activate EL2
+EL2->EL3: **SDEI_EVENT_REGISTER**(ev, handler, ...)
+EL3->EL2: success
+EL2->EL3: **SDEI_EVENT_ENABLE**(ev)
+EL3->EL2: success
+EL2->EL3: **SDEI_PE_UNMASK**()
+EL3->EL2: 1
+
+... <<Business as usual>> ...
+
+EL3<--]: **CRITICAL EVENT**
+activate EL3 #red
+note over EL3: Critical event triage
+EL3->SEL1: dispatch
+activate SEL1 #salmon
+note over SEL1: Critical event handling
+SEL1->EL3: done
+deactivate SEL1
+EL3-->EL3: sdei_dispatch_event(ev)
+note over EL3: Prepare SDEI dispatch
+EL3->EL2: dispatch
+activate EL2 #salmon
+note over EL2: SDEI handler
+EL2->EL3: **SDEI_EVENT_COMPLETE()**
+deactivate EL2
+note over EL3: Complete SDEI dispatch
+EL3->EL2: resumes preempted execution
+deactivate EL3
+
+... <<Normal execution resumes>> ...
+
+@enduml

docs/plantuml/sdei_explicit_dispatch.svg

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docs/plantuml/sdei_general.puml

+/'
+ ' Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ '
+ ' SPDX-License-Identifier: BSD-3-Clause
+ '/
+
+@startuml
+
+autonumber "<b>[#]</b>"
+participant "SDEI client" as EL2
+participant EL3
+participant "SDEI interrupt source" as SDEI
+
+activate EL2
+EL2->EL3: **SDEI_INTERRUPT_BIND**(irq)
+EL3->EL2: event number: ev
+EL2->EL3: **SDEI_EVENT_REGISTER**(ev, handler, ...)
+EL3->EL2: success
+EL2->EL3: **SDEI_EVENT_ENABLE**(ev)
+EL3->EL2: success
+EL2->EL3: **SDEI_PE_UNMASK**()
+EL3->EL2: 1
+
+... <<Business as usual>> ...
+
+SDEI-->EL3: SDEI interrupt
+activate SDEI #salmon
+activate EL3 #red
+note over EL3: Prepare SDEI dispatch
+EL3->EL2: dispatch
+activate EL2 #salmon
+note over EL2: SDEI handler
+EL2->EL3: **SDEI_EVENT_COMPLETE()**
+deactivate EL2
+note over EL3: Complete SDEI dispatch
+EL3-->SDEI: EOI
+deactivate SDEI
+EL3->EL2: resumes preempted execution
+deactivate EL3
+
+... <<Normal execution resumes>> ...
+
+@enduml

docs/plantuml/sdei_general.svg

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\ No newline at end of file

docs/platform-interrupt-controller-API.rst

@@ -292,6 +292,22 @@ inserts to order memory updates before updating mask, then writes to the GIC
 *Priority Mask Register*, and make sure memory updates are visible before
 potential trigger due to mask update.
 
+Function: unsigned int plat_ic_get_interrupt_id(unsigned int raw); [optional]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+::
+
+    Argument : unsigned int
+    Return   : unsigned int
+
+This API should extract and return the interrupt number from the raw value
+obtained by the acknowledging the interrupt (read using
+``plat_ic_acknowledge_interrupt()``). If the interrupt ID is invalid, this API
+should return ``INTR_ID_UNAVAILABLE``.
+
+In case of ARM standard platforms using GIC, the implementation of the API
+masks out the interrupt ID field from the acknowledged value from GIC.
+
 ----
 
 *Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.*

docs/porting-guide.rst

@@ -1904,6 +1904,74 @@ calculated by the linker then a link time assertion is raised. A compile time
 assertion is raised if the value of the constant is not aligned to the cache
 line boundary.
 
+SDEI porting requirements
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The SDEI dispatcher requires the platform to provide the following macros
+and functions, of which some are optional, and some others mandatory.
+
+Macros
+......
+
+Macro: PLAT_SDEI_NORMAL_PRI [mandatory]
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+This macro must be defined to the EL3 exception priority level associated with
+Normal SDEI events on the platform. This must have a higher value (therefore of
+lower priority) than ``PLAT_SDEI_CRITICAL_PRI``.
+
+Macro: PLAT_SDEI_CRITICAL_PRI [mandatory]
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+This macro must be defined to the EL3 exception priority level associated with
+Critical SDEI events on the platform. This must have a lower value (therefore of
+higher priority) than ``PLAT_SDEI_NORMAL_PRI``.
+
+It's recommended that SDEI exception priorities in general are assigned the
+lowest among Secure priorities. Among the SDEI exceptions, Critical SDEI
+priority must be higher than Normal SDEI priority.
+
+Functions
+.........
+
+Function: int plat_sdei_validate_entry_point(uintptr_t ep) [optional]
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+::
+
+  Argument: uintptr_t
+  Return: int
+
+This function validates the address of client entry points provided for both
+event registration and *Complete and Resume* SDEI calls. The function takes one
+argument, which is the address of the handler the SDEI client requested to
+register. The function must return ``0`` for successful validation, or ``-1``
+upon failure.
+
+The default implementation always returns ``0``. On ARM platforms, this function
+is implemented to translate the entry point to physical address, and further to
+ensure that the address is located in Non-secure DRAM.
+
+Function: void plat_sdei_handle_masked_trigger(uint64_t mpidr, unsigned int intr) [optional]
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+::
+
+  Argument: uint64_t
+  Argument: unsigned int
+  Return: void
+
+SDEI specification requires that a PE comes out of reset with the events masked.
+The client therefore is expected to call ``PE_UNMASK`` to unmask SDEI events on
+the PE. No SDEI events can be dispatched until such time.
+
+Should a PE receive an interrupt that was bound to an SDEI event while the
+events are masked on the PE, the dispatcher implementation invokes the function
+``plat_sdei_handle_masked_trigger``. The MPIDR of the PE that received the
+interrupt and the interrupt ID are passed as parameters.
+
+The default implementation only prints out a warning message.
+
 Power State Coordination Interface (in BL31)
 --------------------------------------------
 
@@ -2479,14 +2547,17 @@ Function : plat\_ic\_acknowledge\_interrupt() [mandatory]
     Return   : uint32_t
 
 This API is used by the CPU to indicate to the platform IC that processing of
-the highest pending interrupt has begun. It should return the id of the
-interrupt which is being processed.
+the highest pending interrupt has begun. It should return the raw, unmodified
+value obtained from the interrupt controller when acknowledging an interrupt.
+The actual interrupt number shall be extracted from this raw value using the API
+`plat_ic_get_interrupt_id()`__.
+
+.. __: platform-interrupt-controller-API.rst#function-unsigned-int-plat-ic-get-interrupt-id-unsigned-int-raw-optional
 
 This function in ARM standard platforms using GICv2, reads the *Interrupt
 Acknowledge Register* (``GICC_IAR``). This changes the state of the highest
 priority pending interrupt from pending to active in the interrupt controller.
-It returns the value read from the ``GICC_IAR``. This value is the id of the
-interrupt whose state has been changed.
+It returns the value read from the ``GICC_IAR``, unmodified.
 
 In the case of ARM standard platforms using GICv3, if the API is invoked
 from EL3, the function reads the system register ``ICC_IAR0_EL1``, *Interrupt
@@ -2494,7 +2565,7 @@ Acknowledge Register group 0*. If the API is invoked from S-EL1, the function
 reads the system register ``ICC_IAR1_EL1``, *Interrupt Acknowledge Register
 group 1*. The read changes the state of the highest pending interrupt from
 pending to active in the interrupt controller. The value read is returned
-and is the id of the interrupt whose state has been changed.
+unmodified.
 
 The TSP uses this API to start processing of the secure physical timer
 interrupt.

docs/sdei.rst

+Software Delegated Exception Interface
+======================================
+
+
+.. section-numbering::
+    :suffix: .
+
+.. contents::
+    :depth: 2
+
+This document provides an overview of the SDEI dispatcher implementation in ARM
+Trusted Firmware.
+
+Introduction
+------------
+
+`Software Delegated Exception Interface`_ (SDEI) is an ARM specification for
+Non-secure world to register handlers with firmware to receive notifications
+about system events. Firmware will first receive the system events by way of
+asynchronous exceptions and, in response, arranges for the registered handler to
+execute in the Non-secure EL.
+
+Normal world software that interacts with the SDEI dispatcher (makes SDEI
+requests and receives notifications) is referred to as the *SDEI Client*. A
+client receives the event notification at the registered handler even when it
+was executing with exceptions masked. The list of SDEI events available to the
+client are specific to the platform [#std-event]_. See also `Determining client
+EL`_.
+
+.. _general SDEI dispatch:
+
+The following figure depicts a general sequence involving SDEI client executing
+at EL2 and an event dispatch resulting from the triggering of a bound interrupt.
+A commentary is provided below:
+
+.. image:: plantuml/sdei_general.svg
+
+As part of initialisation, the SDEI client binds a Non-secure interrupt [1], and
+the SDEI dispatcher returns a platform dynamic event number [2]. The client then
+registers a handler for that event [3], enables the event [5], and unmasks all
+events on the current PE [7]. This sequence is typical of an SDEI client, but it
+may involve additional SDEI calls.
+
+At a later point in time, when the bound interrupt triggers [9], it's trapped to
+EL3. The interrupt is handed over to the SDEI dispatcher, which then arranges to
+execute the registered handler [10]. The client terminates its execution with
+``SDEI_EVENT_COMPLETE`` [11], following which the dispatcher resumes the
+original EL2 execution [13]. Note that the SDEI interrupt remains active until
+the client handler completes, at which point EL3 does EOI [12].
+
+SDEI events can be explicitly dispatched in response to other asynchronous
+exceptions. See `Explicit dispatch of events`_.
+
+The remainder of this document only discusses the design and implementation of
+SDEI dispatcher in ARM Trusted Firmware, and assumes that the reader is familiar
+with the SDEI specification, the interfaces, and their requirements.
+
+.. [#std-event] Except event 0, which is defined by the SDEI specification as a
+                standard event.
+
+Defining events
+---------------
+
+A platform choosing to include the SDEI dispatcher must also define the events
+available on the platform, along with their attributes.
+
+The platform is expected to provide two arrays of event descriptors: one for
+private events, and another for shared events. The SDEI dispatcher provides
+``SDEI_PRIVATE_EVENT()`` and ``SDEI_SHARED_EVENT()`` macros to populate the
+event descriptors. Both macros take 3 arguments:
+
+-  The event number: this must be a positive 32-bit integer.
+
+-  The interrupt number the event is bound to:
+
+   - If it's not applicable to an event, this shall be left as ``0``.
+
+   - If the event is dynamic, this should be specified as ``SDEI_DYN_IRQ``.
+
+-  A bit map of `Event flags`_.
+
+To define event 0, the macro ``SDEI_DEFINE_EVENT_0()`` should be used. This
+macro takes only one parameter: an SGI number to signal other PEs.
+
+Once the event descriptor arrays are defined, they should be exported to the
+SDEI dispatcher using the ``REGISTER_SDEI_MAP()`` macro, passing it the pointers
+to the private and shared event descriptor arrays, respectively. Note that the
+``REGISTER_SDEI_MAP()`` macro must be used in the same file where the arrays are
+defined.
+
+Regarding event descriptors:
+
+-  For Event 0:
+
+   - There must be exactly one descriptor in the private array, and none in the
+     shared array.
+
+   - The event should be defined using ``SDEI_DEFINE_EVENT_0()``.
+
+   - Must be bound to a Secure SGI on the platform.
+
+-  Statically bound shared and private interrupts must be bound to shared and
+   private interrupts on the platform, respectively. See the section on
+   `interrupt configuration`__.
+
+   .. __: `Configuration within Exception Handling Framework`_
+
+-  Both arrays should be one-dimensional. The ``REGISTER_SDEI_MAP()`` macro
+   takes care of replicating private events for each PE on the platform.
+
+-  Both arrays must be sorted in the increasing order of event number.
+
+The SDEI specification doesn't have provisions for discovery of available events
+on the platform. The list of events made available to the client, along with
+their semantics, have to be communicated out of band; for example, through
+Device Trees or firmware configuration tables.
+
+See also `Event definition example`_.
+
+Event flags
+~~~~~~~~~~~
+
+Event flags describe the properties of the event. They are bit maps that can be
+``OR``\ ed to form parameters to macros that `define events`__.
+
+.. __: `Defining events`_
+
+-  ``SDEI_MAPF_DYNAMIC``: Marks the event as dynamic. Dynamic events can be
+   bound to (or released from) any Non-secure interrupt at runtime via. the
+   ``SDEI_INTERRUPT_BIND`` and ``SDEI_INTERRUPT_RELEASE`` calls.
+
+-  ``SDEI_MAPF_BOUND``: Marks the event as statically bound to an interrupt.
+   These events cannot be re-bound at runtime.
+
+-  ``SDEI_MAPF_CRITICAL``: Marks the event as having *Critical* priority.
+   Without this flag, the event is assumed to have *Normal* priority.
+
+Event definition example
+------------------------
+
+.. code:: c
+
+   static sdei_ev_map_t plat_private_sdei[] = {
+        /* Event 0 definition */
+        SDEI_DEFINE_EVENT_0(8),
+
+        /* PPI */
+        SDEI_PRIVATE_EVENT(8, 23, SDEI_MAPF_BOUND),
+
+        /* Dynamic private events */
+        SDEI_PRIVATE_EVENT(100, SDEI_DYN_IRQ, SDEI_MAPF_DYNAMIC),
+        SDEI_PRIVATE_EVENT(101, SDEI_DYN_IRQ, SDEI_MAPF_DYNAMIC)
+   };
+
+   /* Shared event mappings */
+   static sdei_ev_map_t plat_shared_sdei[] = {
+        SDEI_SHARED_EVENT(804, 0, SDEI_MAPF_DYNAMIC),
+
+        /* Dynamic shared events */
+        SDEI_SHARED_EVENT(3000, SDEI_DYN_IRQ, SDEI_MAPF_DYNAMIC),
+        SDEI_SHARED_EVENT(3001, SDEI_DYN_IRQ, SDEI_MAPF_DYNAMIC)
+   };
+
+   /* Export SDEI events */
+   REGISTER_SDEI_MAP(plat_private_sdei, plat_shared_sdei);
+
+Configuration within Exception Handling Framework
+-------------------------------------------------
+
+The SDEI dispatcher functions alongside the Exception Handling Framework. This
+means that the platform must assign priorities to both Normal and Critical SDEI
+interrupts for the platform:
+
+-  Install priority descriptors for Normal and Critical SDEI interrupts.
+
+-  For those interrupts that are statically bound (i.e. events defined as having
+   the ``SDEI_MAPF_BOUND`` property), enumerate their properties for the GIC
+   driver to configure interrupts accordingly.
+
+   The interrupts must be configured to target EL3. This means that they should
+   be configured as *Group 0*.  Additionally, on GICv2 systems, the build option
+   ``GICV2_G0_FOR_EL3`` must be set to ``1``.
+
+See also `SDEI porting requirements`_.
+
+Determining client EL
+---------------------
+
+The SDEI specification requires that the *physical* SDEI client executes in the
+highest Non-secure EL implemented on the system. This means that the dispatcher
+will only allow SDEI calls to be made from:
+
+-  EL2, if EL2 is implemented. The Hypervisor is expected to implement a
+   *virtual* SDEI dispatcher to support SDEI clients in Guest Operating Systems
+   executing in Non-secure EL1.
+
+-  Non-secure EL1, if EL2 is not implemented or disabled.
+
+See the function ``sdei_client_el()`` in ``sdei_private.h``.
+
+Explicit dispatch of events
+---------------------------
+
+Typically, an SDEI event dispatch is caused by the PE receiving interrupts that
+are bound to an SDEI event. However, there are cases where the Secure world
+requires dispatch of an SDEI event as a direct or indirect result of a past
+activity, viz. receiving a Secure interrupt or an exception.
+
+The SDEI dispatcher implementation provides ``sdei_dispatch_event()`` API for
+this purpose. The API has the following signature:
+
+::
+
+        int sdei_dispatch_event(int ev_num, unsigned int preempted_sec_state);
+
+-  The parameter ``ev_num`` is the event number to dispatch;
+
+-  The parameter ``preempted_sec_state`` indicates the context that was
+   preempted. This must be either ``SECURE`` or ``NON_SECURE``.
+
+The API returns ``0`` on success, or ``-1`` on failure.
+
+The following figure depicts a scenario involving explicit dispatch of SDEI
+event. A commentary is provided below:
+
+.. image:: plantuml/sdei_explicit_dispatch.svg
+
+As part of initialisation, the SDEI client registers a handler for a platform
+event [1], enables the event [3], and unmasks the current PE [5]. Note that,
+unlike in `general SDEI dispatch`_, this doesn't involve interrupt binding, as
+bound or dynamic events can't be explicitly dispatched (see the section below).
+
+At a later point in time, a critical event [#critical-event]_ is trapped into
+EL3 [7]. EL3 performs a first-level triage of the event, and decides to dispatch
+to Secure EL1 for further handling [8]. The dispatch completes, but intends to
+involve Non-secure world in further handling, and therefore decides to
+explicitly dispatch an event [10] (which the client had already registered for
+[1]). The rest of the sequence is similar to that in the `general SDEI
+dispatch`_: the requested event is dispatched to the client (assuming all the
+conditions are met), and when the handler completes, the preempted execution
+resumes.
+
+Conditions for event dispatch
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+All of the following requirements must be met for the API to return ``0`` and
+event to be dispatched:
+
+-  SDEI events must be unmasked on the PE. I.e. the client must have called
+   ``PE_UNMASK`` beforehand.
+
+-  Event 0 can't be dispatched.
+
+-  The event must neither be a dynamic event nor be bound to an interrupt.
+
+-  The event must be private to the PE.
+
+-  The event must have been registered for and enabled.
+
+-  A dispatch for the same event must not be outstanding. I.e. it hasn't already
+   been dispatched and is yet to be completed.
+
+-  The priority of the event (either Critical or Normal, as configured by the
+   platform at build-time) shouldn't cause priority inversion. This means:
+
+   -  If it's of Normal priority, neither Normal nor Critical priority dispatch
+      must be outstanding on the PE.
+
+   -  If it's of a Critical priority, no Critical priority dispatch must be
+      outstanding on the PE.
+
+Further, the caller should be aware of the following assumptions made by the
+dispatcher:
+
+-  The caller of the API is a component running in EL3; for example, the *Secure
+   Partition Manager*.
+
+-  The requested dispatch will be permitted by the Exception Handling Framework.
+   I.e. the caller must make sure that the requested dispatch has sufficient
+   priority so as not to cause priority level inversion within Exception
+   Handling Framework.
+
+-  At the time of the call, the active context is Secure, and it has been saved.
+
+-  Upon returning success, the Non-secure context will be restored and setup for
+   the event dispatch, and it will be the active context. The Non-secure context
+   should not be modified further by the caller.
+
+-  The API returning success only means that the dispatch is scheduled at the
+   next ``ERET``, and not immediately performed. Also, the caller must be
+   prepared for this API to return failure and handle accordingly.
+
+-  Upon completing the event (i.e. when the client calls either
+   ``SDEI_EVENT_COMPLETE`` or ``SDEI_COMPLETE_AND_RESUME``), the preempted
+   context is resumed (as indicated by the ``preempted_sec_state`` parameter of
+   the API).
+
+.. [#critical-event] Examples of critical event are *SError*, *Synchronous
+                     External Abort*, *Fault Handling interrupt*, or *Error
+                     Recovery interrupt* from one of RAS nodes in the system.
+
+Porting requirements
+--------------------
+
+The porting requirements of the SDEI dispatcher are outlined in the `porting
+guide`__.
+
+.. __: `SDEI porting requirements`_
+
+Note on writing SDEI event handlers
+-----------------------------------
+
+*This section pertains to SDEI event handlers in general, not just when using
+ARM Trusted Firmware SDEI dispatcher.*
+
+The SDEI specification requires that event handlers preserve the contents of all
+registers except ``x0`` to ``x17``. This has significance if event handler is
+written in C: compilers typically adjust the stack frame at the beginning and
+end of C functions. For example, AArch64 GCC typically produces the following
+function prologue and epilogue:
+
+::
+
+        c_event_handler:
+                stp     x29, x30, [sp,#-32]!
+                mov     x29, sp
+
+                ...
+
+                bl      ...
+
+                ...
+
+                ldp     x29, x30, [sp],#32
+                ret
+
+The register ``x29`` is used as frame pointer in the prologue. Because neither a
+valid ``SDEI_EVENT_COMPLETE`` nor ``SDEI_EVENT_COMPLETE_AND_RESUME`` calls
+return to the handler, the epilogue never gets executed, and registers ``x29``
+and ``x30`` (in the case above) are inadvertently corrupted. This violates the
+SDEI specification, and the normal execution thereafter will result in
+unexpected behaviour.
+
+To work this around, it's advised that the top-level event handlers are
+implemented in assembly, following a similar pattern as below:
+
+::
+
+        asm_event_handler:
+                /* Save link register whilst maintaining stack alignment */
+                stp     xzr, x30, [sp, #-16]!
+                bl      c_event_handler
+
+                /* Restore link register */
+                ldp     xzr, x30, [sp], #16
+
+                /* Complete call */
+                ldr     x0, =SDEI_EVENT_COMPLETE
+                smc     #0
+                b       .
+
+----
+
+*Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.*
+
+.. _SDEI specification: http://infocenter.arm.com/help/topic/com.arm.doc.den0054a/ARM_DEN0054A_Software_Delegated_Exception_Interface.pdf
+.. _SDEI porting requirements: porting-guide.rst#sdei-porting-requirements

docs/user-guide.rst

@@ -361,6 +361,11 @@ Common build options
    Firmware as error. It can take the value 1 (flag the use of deprecated
    APIs as error) or 0. The default is 0.
 
+-  ``EL3_EXCEPTION_HANDLING``: When set to ``1``, enable handling of exceptions
+   targeted at EL3. When set ``0`` (default), no exceptions are expected or
+   handled at EL3, and a panic will result. This is supported only for AArch64
+   builds.
+
 -  ``FIP_NAME``: This is an optional build option which specifies the FIP
    filename for the ``fip`` target. Default is ``fip.bin``.
 
@@ -529,6 +534,12 @@ Common build options
    optional. It is only needed if the platform makefile specifies that it
    is required in order to build the ``fwu_fip`` target.
 
+-  ``SDEI_SUPPORT``: Setting this to ``1`` enables support for Software
+   Delegated Exception Interface to BL31 image. This defaults to ``0``.
+
+   When set to ``1``, the build option ``EL3_EXCEPTION_HANDLING`` must also be
+   set to ``1``.
+
 -  ``SEPARATE_CODE_AND_RODATA``: Whether code and read-only data should be
    isolated on separate memory pages. This is a trade-off between security and
    memory usage. See "Isolating code and read-only data on separate memory

drivers/arm/gic/v2/gicv2_main.c

@@ -72,6 +72,8 @@ void gicv2_cpuif_disable(void)
  ******************************************************************************/
 void gicv2_pcpu_distif_init(void)
 {
+	unsigned int ctlr;
+
 	assert(driver_data);
 	assert(driver_data->gicd_base);
 
@@ -89,6 +91,13 @@ void gicv2_pcpu_distif_init(void)
 				driver_data->g0_interrupt_array);
 	}
 #endif
+
+	/* Enable G0 interrupts if not already */
+	ctlr = gicd_read_ctlr(driver_data->gicd_base);
+	if ((ctlr & CTLR_ENABLE_G0_BIT) == 0) {
+		gicd_write_ctlr(driver_data->gicd_base,
+				ctlr | CTLR_ENABLE_G0_BIT);
+	}
 }
 
 /*******************************************************************************
@@ -308,9 +317,26 @@ void gicv2_set_pe_target_mask(unsigned int proc_num)
 	if (driver_data->target_masks[proc_num])
 		return;
 
-	/* Read target register corresponding to this CPU */
-	driver_data->target_masks[proc_num] =
-		gicv2_get_cpuif_id(driver_data->gicd_base);
+	/*
+	 * Update target register corresponding to this CPU and flush for it to
+	 * be visible to other CPUs.
+	 */
+	if (driver_data->target_masks[proc_num] == 0) {
+		driver_data->target_masks[proc_num] =
+			gicv2_get_cpuif_id(driver_data->gicd_base);
+#if !HW_ASSISTED_COHERENCY
+		/*
+		 * PEs only update their own masks. Primary updates it with
+		 * caches on. But because secondaries does it with caches off,
+		 * all updates go to memory directly, and there's no danger of
+		 * secondaries overwriting each others' mask, despite
+		 * target_masks[] not being cache line aligned.
+		 */
+		flush_dcache_range((uintptr_t)
+				&driver_data->target_masks[proc_num],
+				sizeof(driver_data->target_masks[proc_num]));
+#endif
+	}
 }
 
 /*******************************************************************************

drivers/arm/gic/v3/gicv3_helpers.c

@@ -541,12 +541,13 @@ void gicv3_secure_ppi_sgi_configure(uintptr_t gicr_base,
 /*******************************************************************************
  * Helper function to configure properties of secure G0 and G1S PPIs and SGIs.
  ******************************************************************************/
-void gicv3_secure_ppi_sgi_configure_props(uintptr_t gicr_base,
+unsigned int gicv3_secure_ppi_sgi_configure_props(uintptr_t gicr_base,
 		const interrupt_prop_t *interrupt_props,
 		unsigned int interrupt_props_num)
 {
 	unsigned int i;
 	const interrupt_prop_t *current_prop;
+	unsigned int ctlr_enable = 0;
 
 	/* Make sure there's a valid property array */
 	assert(interrupt_props != NULL);
@@ -564,10 +565,13 @@ void gicv3_secure_ppi_sgi_configure_props(uintptr_t gicr_base,
 		/* Configure this interrupt as G0 or a G1S interrupt */
 		assert((current_prop->intr_grp == INTR_GROUP0) ||
 				(current_prop->intr_grp == INTR_GROUP1S));
-		if (current_prop->intr_grp == INTR_GROUP1S)
+		if (current_prop->intr_grp == INTR_GROUP1S) {
 			gicr_set_igrpmodr0(gicr_base, current_prop->intr_num);
-		else
+			ctlr_enable |= CTLR_ENABLE_G1S_BIT;
+		} else {
 			gicr_clr_igrpmodr0(gicr_base, current_prop->intr_num);
+			ctlr_enable |= CTLR_ENABLE_G0_BIT;
+		}
 
 		/* Set the priority of this interrupt */
 		gicr_set_ipriorityr(gicr_base, current_prop->intr_num,
@@ -586,4 +590,6 @@ void gicv3_secure_ppi_sgi_configure_props(uintptr_t gicr_base,
 		/* Enable this interrupt */
 		gicr_set_isenabler0(gicr_base, current_prop->intr_num);
 	}
+
+	return ctlr_enable;
 }

drivers/arm/gic/v3/gicv3_main.c

@@ -224,12 +224,16 @@ void gicv3_distif_init(void)
 void gicv3_rdistif_init(unsigned int proc_num)
 {
 	uintptr_t gicr_base;
+	unsigned int bitmap = 0;
+	uint32_t ctlr;
 
 	assert(gicv3_driver_data);
 	assert(proc_num < gicv3_driver_data->rdistif_num);
 	assert(gicv3_driver_data->rdistif_base_addrs);
 	assert(gicv3_driver_data->gicd_base);
-	assert(gicd_read_ctlr(gicv3_driver_data->gicd_base) & CTLR_ARE_S_BIT);
+
+	ctlr = gicd_read_ctlr(gicv3_driver_data->gicd_base);
+	assert(ctlr & CTLR_ARE_S_BIT);
 
 	assert(IS_IN_EL3());
 
@@ -244,7 +248,7 @@ void gicv3_rdistif_init(unsigned int proc_num)
 #if !ERROR_DEPRECATED
 	if (gicv3_driver_data->interrupt_props != NULL) {
 #endif
-		gicv3_secure_ppi_sgi_configure_props(gicr_base,
+		bitmap = gicv3_secure_ppi_sgi_configure_props(gicr_base,
 				gicv3_driver_data->interrupt_props,
 				gicv3_driver_data->interrupt_props_num);
 #if !ERROR_DEPRECATED
@@ -258,6 +262,7 @@ void gicv3_rdistif_init(unsigned int proc_num)
 					gicv3_driver_data->g1s_interrupt_num,
 					gicv3_driver_data->g1s_interrupt_array,
 					INTR_GROUP1S);
+			bitmap |= CTLR_ENABLE_G1S_BIT;
 		}
 
 		/* Configure the G0 SGIs/PPIs */
@@ -266,9 +271,14 @@ void gicv3_rdistif_init(unsigned int proc_num)
 					gicv3_driver_data->g0_interrupt_num,
 					gicv3_driver_data->g0_interrupt_array,
 					INTR_GROUP0);
+			bitmap |= CTLR_ENABLE_G0_BIT;
 		}
 	}
 #endif
+
+	/* Enable interrupt groups as required, if not already */
+	if ((ctlr & bitmap) != bitmap)
+		gicd_set_ctlr(gicv3_driver_data->gicd_base, bitmap, RWP_TRUE);
 }
 
 /*******************************************************************************

drivers/arm/gic/v3/gicv3_private.h

@@ -95,7 +95,7 @@ void gicv3_secure_ppi_sgi_configure(uintptr_t gicr_base,
 					const unsigned int *sec_intr_list,
 					unsigned int int_grp);
 #endif
-void gicv3_secure_ppi_sgi_configure_props(uintptr_t gicr_base,
+unsigned int gicv3_secure_ppi_sgi_configure_props(uintptr_t gicr_base,
 		const interrupt_prop_t *interrupt_props,
 		unsigned int interrupt_props_num);
 unsigned int gicv3_secure_spis_configure_props(uintptr_t gicd_base,

include/bl31/ehf.h

+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef __EHF_H__
+#define __EHF_H__
+
+#ifndef __ASSEMBLY__
+
+#include <stdint.h>
+#include <utils_def.h>
+
+/* Valid priorities set bit 0 of the priority handler. */
+#define _EHF_PRI_VALID	(((uintptr_t) 1) << 0)
+
+/* Marker for no handler registered for a valid priority */
+#define _EHF_NO_HANDLER	(0 | _EHF_PRI_VALID)
+
+/* Extract the specified number of top bits from 7 lower bits of priority */
+#define EHF_PRI_TO_IDX(pri, plat_bits) \
+	((pri & 0x7f) >> (7 - plat_bits))
+
+/* Install exception priority descriptor at a suitable index */
+#define EHF_PRI_DESC(plat_bits, priority) \
+	[EHF_PRI_TO_IDX(priority, plat_bits)] = { \
+		.ehf_handler = _EHF_NO_HANDLER, \
+	}
+
+/* Macro for platforms to regiter its exception priorities */
+#define EHF_REGISTER_PRIORITIES(priorities, num, bits) \
+	const ehf_priorities_t exception_data = { \
+		.num_priorities = num, \
+		.ehf_priorities = priorities, \
+		.pri_bits = bits, \
+	}
+
+/*
+ * Priority stack, managed as a bitmap.
+ *
+ * Currently only supports 32 priority levels, allowing platforms to use up to 5
+ * top bits of priority. But the type can be changed to uint64_t should need
+ * arise to support 64 priority levels, allowing platforms to use up to 6 top
+ * bits of priority.
+ */
+typedef uint32_t ehf_pri_bits_t;
+
+/*
+ * Per-PE exception data. The data for each PE is kept as a per-CPU data field.
+ * See cpu_data.h.
+ */
+typedef struct {
+	ehf_pri_bits_t active_pri_bits;
+
+	/* Priority mask value before any priority levels were active */
+	uint8_t init_pri_mask;
+
+	/* Non-secure priority mask value stashed during Secure execution */
+	uint8_t ns_pri_mask;
+} __aligned(sizeof(uint64_t)) pe_exc_data_t;
+
+typedef int (*ehf_handler_t)(uint32_t intr_raw, uint32_t flags, void *handle,
+		void *cookie);
+
+typedef struct ehf_pri_desc {
+	/*
+	 * 4-byte-aligned exception handler. Bit 0 indicates the corresponding
+	 * priority level is valid. This is effectively of ehf_handler_t type,
+	 * but left as uintptr_t in order to make pointer arithmetic convenient.
+	 */
+	uintptr_t ehf_handler;
+} ehf_pri_desc_t;
+
+typedef struct ehf_priorities {
+	ehf_pri_desc_t *ehf_priorities;
+	unsigned int num_priorities;
+	int pri_bits;
+} ehf_priorities_t;
+
+void ehf_init(void);
+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);
+unsigned int ehf_is_ns_preemption_allowed(void);
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __EHF_H__ */

include/drivers/arm/gic_common.h

@@ -34,10 +34,10 @@
 #define GIC_INTR_CFG_EDGE		1
 
 /* Constants to categorise priorities */
-#define GIC_HIGHEST_SEC_PRIORITY	0
-#define GIC_LOWEST_SEC_PRIORITY		127
-#define GIC_HIGHEST_NS_PRIORITY		128
-#define GIC_LOWEST_NS_PRIORITY		254 /* 255 would disable an interrupt */
+#define GIC_HIGHEST_SEC_PRIORITY	0x0
+#define GIC_LOWEST_SEC_PRIORITY		0x7f
+#define GIC_HIGHEST_NS_PRIORITY		0x80
+#define GIC_LOWEST_NS_PRIORITY		0xfe /* 0xff would disable all interrupts */
 
 /*******************************************************************************
  * GIC Distributor interface register offsets that are common to GICv3 & GICv2

include/drivers/arm/gicv3.h

@@ -245,6 +245,9 @@
 #define GICR_NUM_REGS(reg_name)	\
 	DIV_ROUND_UP_2EVAL(TOTAL_PCPU_INTR_NUM, (1 << reg_name ## _SHIFT))
 
+/* Interrupt ID mask for HPPIR, AHPPIR, IAR and AIAR CPU Interface registers */
+#define INT_ID_MASK	0xffffff
+
 /*******************************************************************************
  * This structure describes some of the implementation defined attributes of the
  * GICv3 IP. It is used by the platform port to specify these attributes in order

include/lib/aarch64/arch.h

@@ -598,4 +598,10 @@
 
 #define MAKE_MAIR_NORMAL_MEMORY(inner, outer)	((inner) | ((outer) << MAIR_NORM_OUTER_SHIFT))
 
+/* PAR_EL1 fields */
+#define PAR_F_SHIFT	0
+#define PAR_F_MASK	1
+#define PAR_ADDR_SHIFT	12
+#define PAR_ADDR_MASK	(BIT(40) - 1) /* 40-bits-wide page address */
+
 #endif /* __ARCH_H__ */