[PATCH v3 1/3] lib: sbi: Add support for Supervisor Software Events extension

Clément Léger cleger at rivosinc.com
Thu Mar 21 08:57:16 PDT 2024


This extension [1] allows to deliver events from SBI to supervisor via a
software mechanism. This extension defines events (either local or
global) which are signaled by the SBI on specific signal sources (IRQ,
exceptions, etc) and are injected to be executed in supervisor mode.

[1] https://lists.riscv.org/g/tech-prs/message/798

Signed-off-by: Clément Léger <cleger at rivosinc.com>
---
 include/sbi/sbi_ecall_interface.h |   79 +-
 include/sbi/sbi_error.h           |    2 +
 include/sbi/sbi_sse.h             |   94 +++
 lib/sbi/objects.mk                |    1 +
 lib/sbi/sbi_init.c                |   13 +
 lib/sbi/sbi_sse.c                 | 1131 +++++++++++++++++++++++++++++
 lib/sbi/sbi_trap.c                |    5 +
 7 files changed, 1324 insertions(+), 1 deletion(-)
 create mode 100644 include/sbi/sbi_sse.h
 create mode 100644 lib/sbi/sbi_sse.c

diff --git a/include/sbi/sbi_ecall_interface.h b/include/sbi/sbi_ecall_interface.h
index 690c31b..a511e0b 100644
--- a/include/sbi/sbi_ecall_interface.h
+++ b/include/sbi/sbi_ecall_interface.h
@@ -33,6 +33,7 @@
 #define SBI_EXT_SUSP				0x53555350
 #define SBI_EXT_CPPC				0x43505043
 #define SBI_EXT_DBTR				0x44425452
+#define SBI_EXT_SSE				0x535345
 
 /* SBI function IDs for BASE extension*/
 #define SBI_EXT_BASE_GET_SPEC_VERSION		0x0
@@ -304,6 +305,80 @@ enum sbi_cppc_reg_id {
 	SBI_CPPC_NON_ACPI_LAST		= SBI_CPPC_TRANSITION_LATENCY,
 };
 
+/* SBI Function IDs for SSE extension */
+#define SBI_EXT_SSE_READ_ATTR		0x00000000
+#define SBI_EXT_SSE_WRITE_ATTR		0x00000001
+#define SBI_EXT_SSE_REGISTER		0x00000002
+#define SBI_EXT_SSE_UNREGISTER		0x00000003
+#define SBI_EXT_SSE_ENABLE		0x00000004
+#define SBI_EXT_SSE_DISABLE		0x00000005
+#define SBI_EXT_SSE_COMPLETE		0x00000006
+#define SBI_EXT_SSE_INJECT		0x00000007
+
+/* SBI SSE Event Attributes. */
+enum sbi_sse_attr_id {
+	SBI_SSE_ATTR_STATUS		= 0x00000000,
+	SBI_SSE_ATTR_PRIO		= 0x00000001,
+	SBI_SSE_ATTR_CONFIG		= 0x00000002,
+	SBI_SSE_ATTR_PREFERRED_HART	= 0x00000003,
+	SBI_SSE_ATTR_ENTRY_PC		= 0x00000004,
+	SBI_SSE_ATTR_ENTRY_ARG		= 0x00000005,
+	SBI_SSE_ATTR_INTERRUPTED_SEPC	= 0x00000006,
+	SBI_SSE_ATTR_INTERRUPTED_FLAGS	= 0x00000007,
+	SBI_SSE_ATTR_INTERRUPTED_A6	= 0x00000008,
+	SBI_SSE_ATTR_INTERRUPTED_A7	= 0x00000009,
+
+	SBI_SSE_ATTR_MAX		= 0x0000000A
+};
+
+#define SBI_SSE_ATTR_STATUS_STATE_OFFSET	0
+#define SBI_SSE_ATTR_STATUS_STATE_MASK		0x3
+#define SBI_SSE_ATTR_STATUS_PENDING_OFFSET	2
+#define SBI_SSE_ATTR_STATUS_INJECT_OFFSET	3
+
+#define SBI_SSE_ATTR_CONFIG_ONESHOT	(1 << 0)
+
+#define SBI_SSE_ATTR_INTERRUPTED_FLAGS_STATUS_SPP	BIT(0)
+#define SBI_SSE_ATTR_INTERRUPTED_FLAGS_STATUS_SPIE	BIT(1)
+#define SBI_SSE_ATTR_INTERRUPTED_FLAGS_HSTATUS_SPV	BIT(2)
+#define SBI_SSE_ATTR_INTERRUPTED_FLAGS_HSTATUS_SPVP	BIT(3)
+
+enum sbi_sse_state {
+	SBI_SSE_STATE_UNUSED     = 0,
+	SBI_SSE_STATE_REGISTERED = 1,
+	SBI_SSE_STATE_ENABLED    = 2,
+	SBI_SSE_STATE_RUNNING    = 3,
+};
+
+/* SBI SSE Event IDs. */
+#define SBI_SSE_EVENT_LOCAL_RAS			0x00000000
+#define	SBI_SSE_EVENT_LOCAL_PLAT_0_START	0x00004000
+#define SBI_SSE_EVENT_LOCAL_PLAT_0_END		0x00007fff
+#define SBI_SSE_EVENT_GLOBAL_RAS		0x00008000
+#define	SBI_SSE_EVENT_GLOBAL_PLAT_0_START	0x00004000
+#define SBI_SSE_EVENT_GLOBAL_PLAT_0_END		0x00007fff
+
+#define SBI_SSE_EVENT_LOCAL_PMU			0x00010000
+#define	SBI_SSE_EVENT_LOCAL_PLAT_1_START	0x00014000
+#define SBI_SSE_EVENT_LOCAL_PLAT_1_END		0x00017fff
+#define	SBI_SSE_EVENT_GLOBAL_PLAT_1_START	0x0001c000
+#define SBI_SSE_EVENT_GLOBAL_PLAT_1_END		0x0001ffff
+
+#define	SBI_SSE_EVENT_LOCAL_PLAT_2_START	0x00024000
+#define SBI_SSE_EVENT_LOCAL_PLAT_2_END		0x00027fff
+#define	SBI_SSE_EVENT_GLOBAL_PLAT_2_START	0x0002c000
+#define SBI_SSE_EVENT_GLOBAL_PLAT_2_END		0x0002ffff
+
+#define SBI_SSE_EVENT_LOCAL_SOFTWARE		0xffff0000
+#define	SBI_SSE_EVENT_LOCAL_PLAT_3_START	0xffff4000
+#define SBI_SSE_EVENT_LOCAL_PLAT_3_END		0xffff7fff
+#define SBI_SSE_EVENT_GLOBAL_SOFTWARE		0xffff8000
+#define	SBI_SSE_EVENT_GLOBAL_PLAT_3_START	0xffffc000
+#define SBI_SSE_EVENT_GLOBAL_PLAT_3_END		0xffffffff
+
+#define SBI_SSE_EVENT_GLOBAL_BIT		(1 << 15)
+#define SBI_SSE_EVENT_PLATFORM_BIT		(1 << 14)
+
 /* SBI base specification related macros */
 #define SBI_SPEC_VERSION_MAJOR_OFFSET		24
 #define SBI_SPEC_VERSION_MAJOR_MASK		0x7f
@@ -324,8 +399,10 @@ enum sbi_cppc_reg_id {
 #define SBI_ERR_ALREADY_STARTED			-7
 #define SBI_ERR_ALREADY_STOPPED			-8
 #define SBI_ERR_NO_SHMEM			-9
+#define SBI_ERR_INVALID_STATE			-10
+#define SBI_ERR_BAD_RANGE			-11
 
-#define SBI_LAST_ERR				SBI_ERR_NO_SHMEM
+#define SBI_LAST_ERR				SBI_ERR_BAD_RANGE
 
 /* clang-format on */
 
diff --git a/include/sbi/sbi_error.h b/include/sbi/sbi_error.h
index a77e3f8..fb78bf6 100644
--- a/include/sbi/sbi_error.h
+++ b/include/sbi/sbi_error.h
@@ -24,6 +24,8 @@
 #define SBI_EALREADY_STARTED	SBI_ERR_ALREADY_STARTED
 #define SBI_EALREADY_STOPPED	SBI_ERR_ALREADY_STOPPED
 #define SBI_ENO_SHMEM		SBI_ERR_NO_SHMEM
+#define SBI_EINVALID_STATE	SBI_ERR_INVALID_STATE
+#define SBI_EBAD_RANGE		SBI_ERR_BAD_RANGE
 
 #define SBI_ENODEV		-1000
 #define SBI_ENOSYS		-1001
diff --git a/include/sbi/sbi_sse.h b/include/sbi/sbi_sse.h
new file mode 100644
index 0000000..390840e
--- /dev/null
+++ b/include/sbi/sbi_sse.h
@@ -0,0 +1,94 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2023 Rivos Systems.
+ */
+
+#ifndef __SBI_SSE_H__
+#define __SBI_SSE_H__
+
+#include <sbi/sbi_types.h>
+#include <sbi/sbi_list.h>
+#include <sbi/riscv_locks.h>
+
+struct sbi_scratch;
+struct sbi_trap_regs;
+struct sbi_ecall_return;
+
+#define EXC_MODE_PP_SHIFT		0
+#define EXC_MODE_PP			BIT(EXC_MODE_PP_SHIFT)
+#define EXC_MODE_PV_SHIFT		1
+#define EXC_MODE_PV			BIT(EXC_MODE_PV_SHIFT)
+#define EXC_MODE_SSTATUS_SPIE_SHIFT	2
+#define EXC_MODE_SSTATUS_SPIE		BIT(EXC_MODE_SSTATUS_SPIE_SHIFT)
+
+
+struct sbi_sse_cb_ops {
+	/**
+	 * Called when hart_id is changed on the event.
+	 */
+	void (*set_hartid_cb)(uint32_t event_id, unsigned long hart_id);
+
+	/**
+	 * Called when the SBI_EXT_SSE_COMPLETE is invoked on the event.
+	 */
+	void (*complete_cb)(uint32_t event_id);
+
+	/**
+	 * Called when the SBI_EXT_SSE_REGISTER is invoked on the event.
+	 */
+	void (*register_cb)(uint32_t event_id);
+
+	/**
+	 * Called when the SBI_EXT_SSE_UNREGISTER is invoked on the event.
+	 */
+	void (*unregister_cb)(uint32_t event_id);
+
+	/**
+	 * Called when the SBI_EXT_SSE_ENABLE is invoked on the event.
+	 */
+	void (*enable_cb)(uint32_t event_id);
+
+	/**
+	 * Called when the SBI_EXT_SSE_DISABLE is invoked on the event.
+	 */
+	void (*disable_cb)(uint32_t event_id);
+};
+
+/* Set the callback operations for an event
+ * @param event_id Event identifier (SBI_SSE_EVENT_*)
+ * @param cb_ops Callback operations
+ * @return 0 on success, error otherwise
+ */
+int sbi_sse_set_cb_ops(uint32_t event_id, const struct sbi_sse_cb_ops *cb_ops);
+
+/* Inject an event to the current hard
+ * @param event_id Event identifier (SBI_SSE_EVENT_*)
+ * @param regs Registers that were used on SBI entry
+ * @return 0 on success, error otherwise
+ */
+int sbi_sse_inject_event(uint32_t event_id);
+
+void sbi_sse_process_pending_events(struct sbi_trap_regs *regs);
+
+
+int sbi_sse_init(struct sbi_scratch *scratch, bool cold_boot);
+void sbi_sse_exit(struct sbi_scratch *scratch);
+
+/* Interface called from sbi_ecall_sse.c */
+int sbi_sse_register(uint32_t event_id, unsigned long handler_entry_pc,
+		     unsigned long handler_entry_arg);
+int sbi_sse_unregister(uint32_t event_id);
+int sbi_sse_enable(uint32_t event_id);
+int sbi_sse_disable(uint32_t event_id);
+int sbi_sse_complete(struct sbi_trap_regs *regs, struct sbi_ecall_return *out);
+int sbi_sse_inject_from_ecall(uint32_t event_id, unsigned long hart_id,
+			      struct sbi_ecall_return *out);
+int sbi_sse_read_attrs(uint32_t event_id, uint32_t base_attr_id,
+		       uint32_t attr_count, unsigned long output_phys_lo,
+		       unsigned long output_phys_hi);
+int sbi_sse_write_attrs(uint32_t event_id, uint32_t base_attr_id,
+			uint32_t attr_count, unsigned long input_phys_lo,
+			unsigned long input_phys_hi);
+
+#endif
diff --git a/lib/sbi/objects.mk b/lib/sbi/objects.mk
index 5d06d25..2b9ac1f 100644
--- a/lib/sbi/objects.mk
+++ b/lib/sbi/objects.mk
@@ -75,6 +75,7 @@ libsbi-objs-y += sbi_platform.o
 libsbi-objs-y += sbi_pmu.o
 libsbi-objs-y += sbi_dbtr.o
 libsbi-objs-y += sbi_scratch.o
+libsbi-objs-y += sbi_sse.o
 libsbi-objs-y += sbi_string.o
 libsbi-objs-y += sbi_system.o
 libsbi-objs-y += sbi_timer.o
diff --git a/lib/sbi/sbi_init.c b/lib/sbi/sbi_init.c
index 796cccc..0dd62d4 100644
--- a/lib/sbi/sbi_init.c
+++ b/lib/sbi/sbi_init.c
@@ -24,6 +24,7 @@
 #include <sbi/sbi_platform.h>
 #include <sbi/sbi_pmu.h>
 #include <sbi/sbi_dbtr.h>
+#include <sbi/sbi_sse.h>
 #include <sbi/sbi_system.h>
 #include <sbi/sbi_string.h>
 #include <sbi/sbi_timer.h>
@@ -319,6 +320,12 @@ static void __noreturn init_coldboot(struct sbi_scratch *scratch, u32 hartid)
 	if (rc)
 		sbi_hart_hang();
 
+        rc = sbi_sse_init(scratch, true);
+        if (rc) {
+                sbi_printf("%s: sse init failed (error %d)\n", __func__, rc);
+                sbi_hart_hang();
+        }
+
 	rc = sbi_pmu_init(scratch, true);
 	if (rc) {
 		sbi_printf("%s: pmu init failed (error %d)\n",
@@ -445,6 +452,10 @@ static void __noreturn init_warm_startup(struct sbi_scratch *scratch,
 	if (rc)
 		sbi_hart_hang();
 
+	rc = sbi_sse_init(scratch, false);
+	if (rc)
+		sbi_hart_hang();
+
 	rc = sbi_pmu_init(scratch, false);
 	if (rc)
 		sbi_hart_hang();
@@ -653,6 +664,8 @@ void __noreturn sbi_exit(struct sbi_scratch *scratch)
 
 	sbi_platform_early_exit(plat);
 
+	sbi_sse_exit(scratch);
+
 	sbi_pmu_exit(scratch);
 
 	sbi_timer_exit(scratch);
diff --git a/lib/sbi/sbi_sse.c b/lib/sbi/sbi_sse.c
new file mode 100644
index 0000000..0fb77aa
--- /dev/null
+++ b/lib/sbi/sbi_sse.c
@@ -0,0 +1,1131 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2023 Rivos Systems Inc.
+ *
+ */
+
+#include <sbi/riscv_asm.h>
+#include <sbi/riscv_barrier.h>
+#include <sbi/riscv_encoding.h>
+#include <sbi/riscv_locks.h>
+#include <sbi/sbi_domain.h>
+#include <sbi/sbi_ecall.h>
+#include <sbi/sbi_ecall_interface.h>
+#include <sbi/sbi_error.h>
+#include <sbi/sbi_fifo.h>
+#include <sbi/sbi_hart.h>
+#include <sbi/sbi_heap.h>
+#include <sbi/sbi_hsm.h>
+#include <sbi/sbi_ipi.h>
+#include <sbi/sbi_list.h>
+#include <sbi/sbi_platform.h>
+#include <sbi/sbi_pmu.h>
+#include <sbi/sbi_sse.h>
+#include <sbi/sbi_scratch.h>
+#include <sbi/sbi_string.h>
+#include <sbi/sbi_trap.h>
+
+#include <sbi/sbi_console.h>
+
+#define sse_get_hart_state_ptr(__scratch) \
+	sbi_scratch_read_type((__scratch), void *, shs_ptr_off)
+
+#define sse_thishart_state_ptr() \
+	sse_get_hart_state_ptr(sbi_scratch_thishart_ptr())
+
+#define sse_set_hart_state_ptr(__scratch, __sse_state) \
+	sbi_scratch_write_type((__scratch), void *, shs_ptr_off, (__sse_state))
+
+#define EVENT_IS_GLOBAL(__event_id) ((__event_id) & SBI_SSE_EVENT_GLOBAL_BIT)
+
+static const uint32_t supported_events[] = {
+	SBI_SSE_EVENT_LOCAL_RAS,
+	SBI_SSE_EVENT_GLOBAL_RAS,
+	SBI_SSE_EVENT_LOCAL_PMU,
+	SBI_SSE_EVENT_LOCAL_SOFTWARE,
+	SBI_SSE_EVENT_GLOBAL_SOFTWARE,
+};
+
+#define EVENT_COUNT array_size(supported_events)
+
+#define sse_event_invoke_cb(_event, _cb, ...)                                 \
+	{                                                                     \
+		if (_event->cb_ops && _event->cb_ops->_cb)                    \
+			_event->cb_ops->_cb(_event->event_id, ##__VA_ARGS__); \
+	}
+
+struct sse_entry_state {
+	/** entry pc */
+	unsigned long pc;
+	/** a6 register state */
+	unsigned long arg;
+};
+
+struct sse_interrupted_state {
+	/** sepc register state */
+	unsigned long sepc;
+	/** flags register state */
+	unsigned long flags;
+	/** a6 register state */
+	unsigned long a6;
+	/** a7 register state */
+	unsigned long a7;
+};
+
+struct sse_ipi_inject_data {
+	uint32_t event_id;
+};
+
+struct sbi_sse_event_attrs {
+	unsigned long status;
+	unsigned long prio;
+	unsigned long config;
+	unsigned long hartid;
+	struct sse_entry_state entry;
+	struct sse_interrupted_state interrupted;
+};
+
+/* Make sure all attributes are packed for direct memcpy in ATTR_READ */
+#define assert_field_offset(field, attr_offset)                  \
+	_Static_assert(                                          \
+		((offsetof(struct sbi_sse_event_attrs, field)) / \
+		 sizeof(unsigned long)) == attr_offset,          \
+		"field " #field                                  \
+		" from struct sbi_sse_event_attrs invalid offset, expected " #attr_offset)
+
+assert_field_offset(status, SBI_SSE_ATTR_STATUS);
+assert_field_offset(prio, SBI_SSE_ATTR_PRIO);
+assert_field_offset(config, SBI_SSE_ATTR_CONFIG);
+assert_field_offset(hartid, SBI_SSE_ATTR_PREFERRED_HART);
+assert_field_offset(entry.pc, SBI_SSE_ATTR_ENTRY_PC);
+assert_field_offset(entry.arg, SBI_SSE_ATTR_ENTRY_ARG);
+assert_field_offset(interrupted.sepc, SBI_SSE_ATTR_INTERRUPTED_SEPC);
+assert_field_offset(interrupted.flags, SBI_SSE_ATTR_INTERRUPTED_FLAGS);
+assert_field_offset(interrupted.a6, SBI_SSE_ATTR_INTERRUPTED_A6);
+assert_field_offset(interrupted.a7, SBI_SSE_ATTR_INTERRUPTED_A7);
+
+struct sbi_sse_event {
+	struct sbi_sse_event_attrs attrs;
+	uint32_t event_id;
+	const struct sbi_sse_cb_ops *cb_ops;
+	struct sbi_dlist node;
+};
+
+/** Per-hart state */
+struct sse_hart_state {
+	/* Priority sorted list of enabled events (global and local in >=
+	 * ENABLED state). This list is protected by the enabled_event_lock.
+	 *
+	 * Global events can also be inserted in this list. Since these events
+	 * can be accessed by all harts, we actually need to lock independently
+	 * (see sse_global_event).
+	 *
+	 * Local events do not actually need to be locked since, we do
+	 * not have preemption and there are solely accessed by the current
+	 * hart. So when inserting a local event in this list, we just need to
+	 * lock the list at insertion/removal time.
+	 *
+	 * When an event is in a state >= ENABLED, then it is inserted in the
+	 * this enabled_event_list and thus can only be removed from this
+	 * list upon disable ecall or on complete with ONE_SHOT flag.
+	 */
+	struct sbi_dlist enabled_event_list;
+
+	/**
+	 * Lock that protects enabled_event_list
+	 */
+	spinlock_t enabled_event_lock;
+
+	/**
+	 * List of local events allocated at boot time.
+	 */
+	struct sbi_sse_event *local_events;
+};
+
+/**
+ * Global events are accessible by all harts
+ */
+struct sse_global_event {
+	/**
+	 * global event struct
+	 */
+	struct sbi_sse_event event;
+
+	/**
+	 * Global event lock protecting access from multiple harts from ecall to
+	 * the event.
+	 */
+	spinlock_t lock;
+};
+
+static unsigned int local_event_count;
+static unsigned int global_event_count;
+static struct sse_global_event *global_events;
+
+static unsigned long sse_inject_fifo_off;
+static unsigned long sse_inject_fifo_mem_off;
+/* Offset of pointer to SSE HART state in scratch space */
+static unsigned long shs_ptr_off;
+
+static u32 sse_ipi_inject_event = SBI_IPI_EVENT_MAX;
+
+static int sse_ipi_inject_send(unsigned long hartid, uint32_t event_id);
+
+static unsigned long sse_event_state(struct sbi_sse_event *e)
+{
+	return e->attrs.status & SBI_SSE_ATTR_STATUS_STATE_MASK;
+}
+
+static unsigned long sse_event_pending(struct sbi_sse_event *e)
+{
+	return !!(e->attrs.status & BIT(SBI_SSE_ATTR_STATUS_PENDING_OFFSET));
+}
+
+static bool sse_event_is_global(struct sbi_sse_event *e)
+{
+	return EVENT_IS_GLOBAL(e->event_id);
+}
+
+static bool sse_event_is_local(struct sbi_sse_event *e)
+{
+	return !sse_event_is_global(e);
+}
+
+/**
+ * If event is global, must be called under global event lock
+ */
+static struct sse_hart_state *sse_get_hart_state(struct sbi_sse_event *e)
+{
+	struct sbi_scratch *s = sbi_hartid_to_scratch(e->attrs.hartid);
+
+	return sse_get_hart_state_ptr(s);
+}
+
+static struct sse_global_event *sse_get_global_event(struct sbi_sse_event* e)
+{
+	return container_of(e, struct sse_global_event, event);
+}
+
+/**
+ * If event is global, must be called under global event lock
+ */
+static void sse_enabled_event_lock(struct sbi_sse_event *e)
+{
+	struct sse_hart_state *shs;
+
+	shs = sse_get_hart_state(e);
+	spin_lock(&shs->enabled_event_lock);
+}
+
+/**
+ * If event is global, must be called under global event lock
+ */
+static void sse_hart_unlock(struct sbi_sse_event *e)
+{
+	struct sse_hart_state *shs;
+
+	shs = sse_get_hart_state(e);
+	spin_unlock(&shs->enabled_event_lock);
+}
+
+static void sse_event_set_state(struct sbi_sse_event *e,
+				unsigned long new_state)
+{
+	e->attrs.status &= ~SBI_SSE_ATTR_STATUS_STATE_MASK;
+	e->attrs.status |= new_state;
+}
+
+static struct sbi_sse_event *sse_event_get(uint32_t event_id)
+{
+	unsigned int i;
+	struct sbi_sse_event *e;
+	struct sse_hart_state *shs;
+
+	if (EVENT_IS_GLOBAL(event_id)) {
+		for (i = 0; i < global_event_count; i++) {
+			e = &global_events[i].event;
+			if (e->event_id == event_id) {
+				spin_lock(&global_events[i].lock);
+				return e;
+			}
+		}
+	} else {
+		shs = sse_thishart_state_ptr();
+		for (i = 0; i < local_event_count; i++) {
+			e = &shs->local_events[i];
+			if (e->event_id == event_id)
+				return e;
+		}
+	}
+
+	return NULL;
+}
+
+static void sse_event_put(struct sbi_sse_event *e)
+{
+	struct sse_global_event *ge;
+
+	if (sse_event_is_local(e))
+		return;
+
+	ge = sse_get_global_event(e);
+	spin_unlock(&ge->lock);
+}
+
+static void sse_event_remove_from_list(struct sbi_sse_event *e)
+{
+	sbi_list_del(&e->node);
+}
+
+/**
+ * Must be called under owner hart lock
+ */
+static void sse_event_add_to_list(struct sbi_sse_event *e)
+{
+	struct sse_hart_state *state = sse_get_hart_state(e);
+	struct sbi_sse_event *tmp;
+
+	sbi_list_for_each_entry(tmp, &state->enabled_event_list, node)
+	{
+		if (e->attrs.prio < tmp->attrs.prio)
+			break;
+		if (e->attrs.prio == tmp->attrs.prio &&
+		    e->event_id < tmp->event_id)
+			break;
+	}
+	sbi_list_add_tail(&e->node, &tmp->node);
+}
+
+/**
+ * Must be called under owner hart lock
+ */
+static int sse_event_disable(struct sbi_sse_event *e)
+{
+	if (sse_event_state(e) != SBI_SSE_STATE_ENABLED)
+		return SBI_EINVALID_STATE;
+
+	sse_event_invoke_cb(e, disable_cb);
+
+	sse_event_remove_from_list(e);
+	sse_event_set_state(e, SBI_SSE_STATE_REGISTERED);
+
+	return SBI_OK;
+}
+
+static int sse_event_set_hart_id_check(struct sbi_sse_event *e,
+				       unsigned long new_hartid)
+{
+	int hstate;
+	unsigned int hartid = (uint32_t)new_hartid;
+	struct sbi_domain *hd = sbi_domain_thishart_ptr();
+
+	if (!sse_event_is_global(e))
+		return SBI_EBAD_RANGE;
+
+	if (!sbi_domain_is_assigned_hart(hd, new_hartid))
+		return SBI_EINVAL;
+
+	hstate = sbi_hsm_hart_get_state(hd, hartid);
+	if (hstate != SBI_HSM_STATE_STARTED)
+		return SBI_EINVAL;
+
+	return SBI_OK;
+}
+
+static int sse_event_set_attr_check(struct sbi_sse_event *e, uint32_t attr_id,
+				    unsigned long val)
+{
+	int ret = SBI_OK;
+
+	switch (attr_id) {
+	case SBI_SSE_ATTR_CONFIG:
+		if (val & ~SBI_SSE_ATTR_CONFIG_ONESHOT)
+			ret = SBI_EINVAL;
+		break;
+	case SBI_SSE_ATTR_PRIO:
+#if __riscv_xlen > 32
+		if (val > 0xFFFFFFFFUL) {
+			ret = SBI_EINVAL;
+			break;
+		}
+#endif
+		break;
+	case SBI_SSE_ATTR_PREFERRED_HART:
+		ret = sse_event_set_hart_id_check(e, val);
+		break;
+	default:
+		ret = SBI_EBAD_RANGE;
+		break;
+	}
+
+	return ret;
+}
+
+static void sse_event_set_attr(struct sbi_sse_event *e, uint32_t attr_id,
+			       unsigned long val)
+{
+	switch (attr_id) {
+	case SBI_SSE_ATTR_CONFIG:
+		e->attrs.config = val;
+		break;
+	case SBI_SSE_ATTR_PRIO:
+		e->attrs.prio = (uint32_t)val;
+		break;
+	case SBI_SSE_ATTR_PREFERRED_HART:
+		e->attrs.hartid = val;
+		sse_event_invoke_cb(e, set_hartid_cb, val);
+		break;
+	}
+}
+
+static int sse_event_register(struct sbi_sse_event *e,
+			      unsigned long handler_entry_pc,
+			      unsigned long handler_entry_arg)
+{
+	if (sse_event_state(e) != SBI_SSE_STATE_UNUSED)
+		return SBI_EINVALID_STATE;
+
+	e->attrs.entry.pc = handler_entry_pc;
+	e->attrs.entry.arg = handler_entry_arg;
+
+	sse_event_set_state(e, SBI_SSE_STATE_REGISTERED);
+
+	sse_event_invoke_cb(e, register_cb);
+
+	return 0;
+}
+
+static int sse_event_unregister(struct sbi_sse_event *e)
+{
+	if (sse_event_state(e) != SBI_SSE_STATE_REGISTERED)
+		return SBI_EINVALID_STATE;
+
+	sse_event_invoke_cb(e, unregister_cb);
+
+	sse_event_set_state(e, SBI_SSE_STATE_UNUSED);
+
+	return 0;
+}
+
+static unsigned long sse_interrupted_flags(unsigned long mstatus)
+{
+	unsigned long hstatus, flags = 0;
+
+	if (mstatus & (MSTATUS_SPIE))
+		flags |= SBI_SSE_ATTR_INTERRUPTED_FLAGS_STATUS_SPIE;
+	if (mstatus & (MSTATUS_SPP))
+		flags |= SBI_SSE_ATTR_INTERRUPTED_FLAGS_STATUS_SPP;
+
+	if (misa_extension('H')) {
+		hstatus = csr_read(CSR_HSTATUS);
+		if (hstatus & HSTATUS_SPV)
+			flags |= SBI_SSE_ATTR_INTERRUPTED_FLAGS_HSTATUS_SPV;
+		if (hstatus & HSTATUS_SPVP)
+			flags |= SBI_SSE_ATTR_INTERRUPTED_FLAGS_HSTATUS_SPVP;
+	}
+
+	return flags;
+}
+
+static void sse_event_inject(struct sbi_sse_event *e,
+			     struct sbi_trap_regs *regs)
+{
+	struct sse_interrupted_state *i_ctx = &e->attrs.interrupted;
+
+	sse_event_set_state(e, SBI_SSE_STATE_RUNNING);
+
+	e->attrs.status = ~BIT(SBI_SSE_ATTR_STATUS_PENDING_OFFSET);
+
+	i_ctx->a6 = regs->a6;
+	i_ctx->a7 = regs->a7;
+	i_ctx->flags = sse_interrupted_flags(regs->mstatus);
+	i_ctx->sepc = csr_read(CSR_SEPC);
+
+	regs->mstatus &= ~(MSTATUS_SPP | SSTATUS_SPIE);
+	if (regs->mstatus & MSTATUS_MPP)
+		regs->mstatus |= MSTATUS_SPP;
+	if (regs->mstatus & MSTATUS_SIE)
+		regs->mstatus |= MSTATUS_SPIE;
+
+	if (misa_extension('H')) {
+		unsigned long hstatus = csr_read(CSR_HSTATUS);
+
+#if __riscv_xlen == 64
+		if (regs->mstatus & MSTATUS_MPV)
+#elif __riscv_xlen == 32
+		if (regs->mstatusH & MSTATUSH_MPV)
+#else
+#error "Unexpected __riscv_xlen"
+#endif
+			hstatus |= HSTATUS_SPV;
+
+		hstatus &= ~HSTATUS_SPVP;
+		if (hstatus & HSTATUS_SPV && regs->mstatus & SSTATUS_SPP)
+				hstatus |= HSTATUS_SPVP;
+
+		csr_write(CSR_HSTATUS, hstatus);
+	}
+	csr_write(CSR_SEPC, regs->mepc);
+
+	/* Setup entry context */
+	regs->a6 = e->attrs.entry.arg;
+	regs->a7 = current_hartid();
+	regs->mepc = e->attrs.entry.pc;
+
+	/* Return to S-mode with virtualization disabled */
+	regs->mstatus &= ~(MSTATUS_MPP | MSTATUS_SIE);
+	regs->mstatus |= (PRV_S << MSTATUS_MPP_SHIFT);
+
+#if __riscv_xlen == 64
+	regs->mstatus &= ~MSTATUS_MPV;
+#elif __riscv_xlen == 32
+	regs->mstatusH &= ~MSTATUSH_MPV;
+#else
+#error "Unexpected __riscv_xlen"
+#endif
+
+}
+
+static void sse_event_resume(struct sbi_sse_event *e,
+			     struct sbi_trap_regs *regs)
+{
+	struct sse_interrupted_state *i_ctx = &e->attrs.interrupted;
+
+	regs->mepc = csr_read(CSR_SEPC);
+
+	regs->mstatus &= ~MSTATUS_MPP;
+	if (regs->mstatus & MSTATUS_SPP)
+		regs->mstatus |= (PRV_S << MSTATUS_MPP_SHIFT);
+
+	if (misa_extension('H')) {
+		unsigned long hstatus = csr_read(CSR_HSTATUS);
+#if __riscv_xlen == 64
+		regs->mstatus &= ~MSTATUS_MPV;
+		if (hstatus & HSTATUS_SPV)
+			regs->mstatus |= MSTATUS_MPV;
+#elif __riscv_xlen == 32
+		regs->mstatusH &= ~MSTATUSH_MPV;
+		if (hstatus & HSTATUS_SPV)
+			regs->mstatusH |= MSTATUSH_MPV;
+#else
+#error "Unexpected __riscv_xlen"
+#endif
+		hstatus &= ~(HSTATUS_SPV | HSTATUS_SPVP);
+		if (i_ctx->flags & SBI_SSE_ATTR_INTERRUPTED_FLAGS_HSTATUS_SPV)
+			hstatus |= HSTATUS_SPV;
+
+		if (i_ctx->flags & SBI_SSE_ATTR_INTERRUPTED_FLAGS_HSTATUS_SPVP)
+			hstatus |= HSTATUS_SPVP;
+
+		csr_write(CSR_HSTATUS, hstatus);
+	}
+
+	regs->mstatus &= ~MSTATUS_SIE;
+	if (regs->mstatus & MSTATUS_SPIE)
+		regs->mstatus |= MSTATUS_SIE;
+
+	regs->mstatus &= ~MSTATUS_SPIE;
+	if (i_ctx->flags & SBI_SSE_ATTR_INTERRUPTED_FLAGS_STATUS_SPIE)
+		regs->mstatus |= MSTATUS_SPIE;
+
+	regs->mstatus &= ~MSTATUS_SPP;
+	if (i_ctx->flags & SBI_SSE_ATTR_INTERRUPTED_FLAGS_STATUS_SPP)
+		regs->mstatus |= MSTATUS_SPP;
+
+	regs->a7 = i_ctx->a7;
+	regs->a6 = i_ctx->a6;
+	csr_write(CSR_SEPC, i_ctx->sepc);
+}
+
+static bool sse_event_is_ready(struct sbi_sse_event *e)
+{
+	if (!sse_event_pending(e) ||
+	    sse_event_state(e) != SBI_SSE_STATE_ENABLED ||
+	    e->attrs.hartid != current_hartid()) {
+		return false;
+	}
+
+	return true;
+}
+
+static bool sse_event_check_inject(struct sbi_sse_event *e,
+				   struct sbi_trap_regs *regs)
+{
+	/*
+	* List of event is ordered by priority, stop at first running
+	* event since all other events after this one are of lower
+	* priority. This means an event of higher priority is already
+	* running.
+	*/
+	if (sse_event_state(e) == SBI_SSE_STATE_RUNNING) {
+		return true;
+	}
+
+	if (sse_event_is_ready(e)) {
+		sse_event_inject(e, regs);
+		return true;
+	}
+
+	return false;
+}
+
+/* Return true if an event has been injected, false otherwise */
+void sbi_sse_process_pending_events(struct sbi_trap_regs *regs)
+{
+	bool ret;
+	struct sbi_sse_event *e;
+	struct sse_hart_state *state = sse_thishart_state_ptr();
+
+	spin_lock(&state->enabled_event_lock);
+
+	if (sbi_list_empty(&state->enabled_event_list))
+		goto out;
+
+	sbi_list_for_each_entry(e, &state->enabled_event_list, node) {
+		ret = sse_event_check_inject(e, regs);
+		if (ret)
+			goto out;
+	}
+
+out:
+	spin_unlock(&state->enabled_event_lock);
+}
+
+static int sse_event_set_pending(struct sbi_sse_event *e)
+{
+	if (sse_event_state(e) != SBI_SSE_STATE_RUNNING &&
+	    sse_event_state(e) != SBI_SSE_STATE_ENABLED)
+		return SBI_EINVALID_STATE;
+
+	e->attrs.status |= BIT(SBI_SSE_ATTR_STATUS_PENDING_OFFSET);
+
+	return SBI_OK;
+}
+
+static void sse_ipi_inject_process(struct sbi_scratch *scratch)
+{
+	struct sbi_sse_event *e;
+	struct sse_ipi_inject_data evt;
+	struct sbi_fifo *sse_inject_fifo_r =
+		sbi_scratch_offset_ptr(scratch, sse_inject_fifo_off);
+
+	/* Mark all queued events as pending */
+	while (!sbi_fifo_dequeue(sse_inject_fifo_r, &evt)) {
+		e = sse_event_get(evt.event_id);
+		if (!e)
+			continue;
+
+		sse_event_set_pending(e);
+		sse_event_put(e);
+	}
+}
+
+static struct sbi_ipi_event_ops sse_ipi_inject_ops = {
+	.name	 = "IPI_SSE_INJECT",
+	.process = sse_ipi_inject_process,
+};
+
+static int sse_ipi_inject_send(unsigned long hartid, uint32_t event_id)
+{
+	int ret;
+	struct sbi_scratch *remote_scratch = NULL;
+	struct sse_ipi_inject_data evt = {event_id};
+	struct sbi_fifo *sse_inject_fifo_r;
+
+	remote_scratch = sbi_hartid_to_scratch(hartid);
+	if (!remote_scratch)
+		return SBI_EINVAL;
+	sse_inject_fifo_r =
+		sbi_scratch_offset_ptr(remote_scratch, sse_inject_fifo_off);
+
+	ret = sbi_fifo_enqueue(sse_inject_fifo_r, &evt);
+	if (ret)
+		return SBI_EFAIL;
+
+	ret = sbi_ipi_send_many(1, hartid, sse_ipi_inject_event, NULL);
+	if (ret)
+		return SBI_EFAIL;
+
+	return SBI_OK;
+}
+
+static int sse_inject_event(uint32_t event_id, unsigned long hartid,
+			    struct sbi_ecall_return *out)
+{
+	int ret;
+	struct sbi_sse_event *e;
+
+	e = sse_event_get(event_id);
+	if (!e)
+		return SBI_EINVAL;
+
+
+	/* In case of global event, provided hart_id is ignored */
+	if (sse_event_is_global(e))
+		hartid = e->attrs.hartid;
+
+	/* Event is for another hart, send it through IPI */
+	if (hartid != current_hartid()) {
+		sse_event_put(e);
+		return sse_ipi_inject_send(hartid, event_id);
+	}
+
+	ret = sse_event_set_pending(e);
+	sse_event_put(e);
+	if (ret)
+		return ret;
+
+	return SBI_OK;
+}
+
+/**
+ * Must be called under owner hart lock
+ */
+static int sse_event_enable(struct sbi_sse_event *e)
+{
+	if (sse_event_state(e) != SBI_SSE_STATE_REGISTERED)
+		return SBI_EINVALID_STATE;
+
+	sse_event_set_state(e, SBI_SSE_STATE_ENABLED);
+	sse_event_add_to_list(e);
+
+	if (sse_event_pending(e))
+		sbi_ipi_send_many(1, e->attrs.hartid, sse_ipi_inject_event,
+				  NULL);
+
+	sse_event_invoke_cb(e, enable_cb);
+
+	return SBI_OK;
+}
+
+static int sse_event_complete(struct sbi_sse_event *e,
+			      struct sbi_trap_regs *regs,
+			      struct sbi_ecall_return *out)
+{
+	if (sse_event_state(e) != SBI_SSE_STATE_RUNNING)
+		return SBI_EINVALID_STATE;
+
+	if (e->attrs.hartid != current_hartid())
+		return SBI_EINVAL;
+
+	sse_event_set_state(e, SBI_SSE_STATE_ENABLED);
+	if (e->attrs.config & SBI_SSE_ATTR_CONFIG_ONESHOT)
+		sse_event_disable(e);
+
+	sse_event_invoke_cb(e, complete_cb);
+
+	sse_event_resume(e, regs);
+	out->skip_regs_update = true;
+
+	return SBI_OK;
+}
+
+int sbi_sse_complete(struct sbi_trap_regs *regs, struct sbi_ecall_return *out)
+{
+	int ret = SBI_OK;
+	struct sbi_sse_event *tmp;
+	struct sse_hart_state *state = sse_thishart_state_ptr();
+
+	spin_lock(&state->enabled_event_lock);
+	sbi_list_for_each_entry(tmp, &state->enabled_event_list, node) {
+		/*
+		 * List of event is ordered by priority, first one running is
+		 * the one that needs to be completed
+		 */
+		if (sse_event_state(tmp) == SBI_SSE_STATE_RUNNING) {
+			ret = sse_event_complete(tmp, regs, out);
+			break;
+		}
+	}
+	spin_unlock(&state->enabled_event_lock);
+
+	return ret;
+}
+
+int sbi_sse_enable(uint32_t event_id)
+{
+	int ret;
+	struct sbi_sse_event *e;
+
+	e = sse_event_get(event_id);
+	if (!e)
+		return SBI_EINVAL;
+
+	sse_enabled_event_lock(e);
+	ret = sse_event_enable(e);
+	sse_hart_unlock(e);
+	sse_event_put(e);
+
+	return ret;
+}
+
+int sbi_sse_disable(uint32_t event_id)
+{
+	int ret;
+	struct sbi_sse_event *e;
+
+	e = sse_event_get(event_id);
+	if (!e)
+		return SBI_EINVAL;
+
+	sse_enabled_event_lock(e);
+	ret = sse_event_disable(e);
+	sse_hart_unlock(e);
+
+	sse_event_put(e);
+
+	return ret;
+}
+
+int sbi_sse_inject_from_ecall(uint32_t event_id, unsigned long hartid,
+			      struct sbi_ecall_return *out)
+{
+	if (!sbi_domain_is_assigned_hart(sbi_domain_thishart_ptr(), hartid))
+		return SBI_EINVAL;
+
+	return sse_inject_event(event_id, hartid, out);
+}
+
+int sbi_sse_inject_event(uint32_t event_id)
+{
+	/* We don't really care about return value here */
+	struct sbi_ecall_return out;
+
+	return sse_inject_event(event_id, current_hartid(), &out);
+}
+
+int sbi_sse_set_cb_ops(uint32_t event_id, const struct sbi_sse_cb_ops *cb_ops)
+{
+	struct sbi_sse_event *e;
+
+	if (cb_ops->set_hartid_cb && !EVENT_IS_GLOBAL(event_id))
+		return SBI_EINVAL;
+
+	e = sse_event_get(event_id);
+	if (!e)
+		return SBI_EINVAL;
+
+	e->cb_ops = cb_ops;
+	sse_event_put(e);
+
+	return SBI_OK;
+}
+
+int sbi_sse_attr_check(uint32_t base_attr_id, uint32_t attr_count,
+		       unsigned long phys_lo, unsigned long phys_hi,
+		       unsigned long access)
+{
+	const unsigned align = __riscv_xlen >> 3;
+	uint64_t end_id = (uint64_t)base_attr_id + (attr_count - 1);
+
+	if (attr_count == 0)
+		return SBI_ERR_INVALID_PARAM;
+
+	if (end_id >= SBI_SSE_ATTR_MAX)
+		return SBI_EBAD_RANGE;
+
+	if (phys_lo & (align - 1))
+		return SBI_EINVALID_ADDR;
+
+	/*
+	 * On RV32, the M-mode can only access the first 4GB of
+	 * the physical address space because M-mode does not have
+	 * MMU to access full 34-bit physical address space.
+	 *
+	 * Based on above, we simply fail if the upper 32bits of
+	 * the physical address (i.e. a2 register) is non-zero on
+	 * RV32.
+	 */
+	if (phys_hi)
+		return SBI_EINVALID_ADDR;
+
+	if (!sbi_domain_check_addr_range(sbi_domain_thishart_ptr(), phys_lo,
+					 sizeof(unsigned long) * attr_count, 1,
+					 access))
+		return SBI_EINVALID_ADDR;
+
+	return SBI_OK;
+}
+
+static void copy_attrs(unsigned long *out, const unsigned long *in,
+		       unsigned int long_count)
+{
+	int i = 0;
+
+	/*
+	 * sbi_memcpy() does byte-per-byte copy, using this yields long-per-long
+	 * copy
+	 */
+	for (i = 0; i < long_count; i++)
+		out[i] = in[i];
+}
+
+int sbi_sse_read_attrs(uint32_t event_id, uint32_t base_attr_id,
+		       uint32_t attr_count, unsigned long output_phys_lo,
+		       unsigned long output_phys_hi)
+{
+	int ret;
+	unsigned long *e_attrs;
+	struct sbi_sse_event *e;
+	unsigned long *attrs;
+
+	ret = sbi_sse_attr_check(base_attr_id, attr_count, output_phys_lo,
+				 output_phys_hi, SBI_DOMAIN_WRITE);
+	if (ret)
+		return ret;
+
+	e = sse_event_get(event_id);
+	if (!e)
+		return SBI_EINVAL;
+
+	sbi_hart_map_saddr(output_phys_lo, sizeof(unsigned long) * attr_count);
+
+	/*
+	 * Copy all attributes at once since struct sse_event_attrs is matching
+	 * the SBI_SSE_ATTR_* attributes. While WRITE_ATTR attribute is not used
+	 * in s-mode sse handling path, READ_ATTR is used to retrieve the value
+	 * of registers when interrupted. Rather than doing multiple SBI calls,
+	 * a single one is done allowing to retrieve them all at once.
+	 */
+	e_attrs = (unsigned long *)&e->attrs;
+	attrs = (unsigned long *)output_phys_lo;
+	copy_attrs(attrs, &e_attrs[base_attr_id], attr_count);
+
+	sbi_hart_unmap_saddr();
+
+	sse_event_put(e);
+
+	return SBI_OK;
+}
+
+static int sse_write_attrs(struct sbi_sse_event *e, uint32_t base_attr_id,
+			   uint32_t attr_count, unsigned long input_phys)
+{
+	int ret = 0;
+	unsigned long attr = 0, val;
+	uint32_t id, end_id = base_attr_id + attr_count;
+	unsigned long *attrs = (unsigned long *)input_phys;
+
+	if (sse_event_state(e) >= SBI_SSE_STATE_ENABLED)
+		return SBI_EINVALID_STATE;
+
+	sbi_hart_map_saddr(input_phys, sizeof(unsigned long) * attr_count);
+
+	for (id = base_attr_id; id < end_id; id++) {
+		val = attrs[attr++];
+		ret = sse_event_set_attr_check(e, id, val);
+		if (ret)
+			goto out;
+	}
+
+	attr = 0;
+	for (id = base_attr_id; id < end_id; id++) {
+		val = attrs[attr++];
+		sse_event_set_attr(e, id, val);
+	}
+
+out:
+	sbi_hart_unmap_saddr();
+
+	return ret;
+}
+
+int sbi_sse_write_attrs(uint32_t event_id, uint32_t base_attr_id,
+			uint32_t attr_count, unsigned long input_phys_lo,
+			unsigned long input_phys_hi)
+{
+	int ret = 0;
+	struct sbi_sse_event *e;
+
+	ret = sbi_sse_attr_check(base_attr_id, attr_count, input_phys_lo,
+				 input_phys_hi, SBI_DOMAIN_READ);
+	if (ret)
+		return ret;
+
+	e = sse_event_get(event_id);
+	if (!e)
+		return SBI_EINVAL;
+
+	ret = sse_write_attrs(e, base_attr_id, attr_count, input_phys_lo);
+
+	sse_event_put(e);
+
+	return ret;
+}
+
+int sbi_sse_register(uint32_t event_id, unsigned long handler_entry_pc,
+		     unsigned long handler_entry_arg)
+{
+	int ret;
+	struct sbi_sse_event *e;
+
+	if (handler_entry_pc & 0x1)
+		return SBI_EINVAL;
+
+	e = sse_event_get(event_id);
+	if (!e)
+		return SBI_EINVAL;
+
+	ret = sse_event_register(e, handler_entry_pc, handler_entry_arg);
+	sse_event_put(e);
+
+	return ret;
+}
+
+int sbi_sse_unregister(uint32_t event_id)
+{
+	int ret;
+	struct sbi_sse_event *e;
+
+	e = sse_event_get(event_id);
+	if (!e)
+		return SBI_EINVAL;
+
+	ret = sse_event_unregister(e);
+	sse_event_put(e);
+
+	return ret;
+}
+
+static void sse_event_init(struct sbi_sse_event *e, uint32_t event_id)
+{
+	e->event_id = event_id;
+	e->attrs.hartid = current_hartid();
+	/* Declare all events as injectable */
+	e->attrs.status |= BIT(SBI_SSE_ATTR_STATUS_INJECT_OFFSET);
+}
+
+static void sse_event_count_init()
+{
+	unsigned int i;
+
+	for (i = 0; i < EVENT_COUNT; i++) {
+		if (EVENT_IS_GLOBAL(supported_events[i]))
+			global_event_count++;
+		else
+			local_event_count++;
+	}
+}
+
+static int sse_global_init()
+{
+	struct sbi_sse_event *e;
+	unsigned int i, ev = 0;
+
+	global_events = sbi_zalloc(sizeof(*global_events) * global_event_count);
+	if (!global_events)
+		return SBI_ENOMEM;
+
+	for (i = 0; i < EVENT_COUNT; i++) {
+		if (!EVENT_IS_GLOBAL(supported_events[i]))
+			continue;
+
+		e = &global_events[ev].event;
+		sse_event_init(e, supported_events[i]);
+		SPIN_LOCK_INIT(global_events[ev].lock);
+
+		ev++;
+	}
+
+	return 0;
+}
+
+static void sse_local_init(struct sse_hart_state *shs)
+{
+	unsigned int i, ev = 0;
+
+	SBI_INIT_LIST_HEAD(&shs->enabled_event_list);
+	SPIN_LOCK_INIT(shs->enabled_event_lock);
+
+	for (i = 0; i < EVENT_COUNT; i++) {
+		if (EVENT_IS_GLOBAL(supported_events[i]))
+			continue;
+
+		sse_event_init(&shs->local_events[ev++], supported_events[i]);
+	}
+}
+
+int sbi_sse_init(struct sbi_scratch *scratch, bool cold_boot)
+{
+	int ret;
+	void *sse_inject_mem;
+	struct sse_hart_state *shs;
+	struct sbi_fifo *sse_inject_q;
+
+	if (cold_boot) {
+		sse_event_count_init();
+
+		ret = sse_global_init();
+		if (ret)
+			return ret;
+
+		shs_ptr_off = sbi_scratch_alloc_offset(sizeof(void *));
+		if (!shs_ptr_off)
+			return SBI_ENOMEM;
+
+		sse_inject_fifo_off =
+			sbi_scratch_alloc_offset(sizeof(*sse_inject_q));
+		if (!sse_inject_fifo_off) {
+			sbi_scratch_free_offset(shs_ptr_off);
+			return SBI_ENOMEM;
+		}
+
+		sse_inject_fifo_mem_off = sbi_scratch_alloc_offset(
+			EVENT_COUNT * sizeof(struct sse_ipi_inject_data));
+		if (!sse_inject_fifo_mem_off) {
+			sbi_scratch_free_offset(sse_inject_fifo_off);
+			sbi_scratch_free_offset(shs_ptr_off);
+			return SBI_ENOMEM;
+		}
+
+		ret = sbi_ipi_event_create(&sse_ipi_inject_ops);
+		if (ret < 0) {
+			sbi_scratch_free_offset(shs_ptr_off);
+			return ret;
+		}
+		sse_ipi_inject_event = ret;
+	}
+
+	shs = sse_get_hart_state_ptr(scratch);
+	if (!shs) {
+		/* Allocate per hart state and local events at once */
+		shs = sbi_zalloc(sizeof(*shs) + sizeof(struct sbi_sse_event) *
+							local_event_count);
+		if (!shs)
+			return SBI_ENOMEM;
+
+		shs->local_events = (struct sbi_sse_event *)(shs + 1);
+
+		sse_set_hart_state_ptr(scratch, shs);
+	}
+
+	sse_local_init(shs);
+
+	sse_inject_q = sbi_scratch_offset_ptr(scratch, sse_inject_fifo_off);
+	sse_inject_mem =
+		sbi_scratch_offset_ptr(scratch, sse_inject_fifo_mem_off);
+
+	sbi_fifo_init(sse_inject_q, sse_inject_mem, EVENT_COUNT,
+		      sizeof(struct sse_ipi_inject_data));
+
+	return 0;
+}
+
+void sbi_sse_exit(struct sbi_scratch *scratch)
+{
+	int i;
+	struct sbi_sse_event *e;
+
+	for (i = 0; i < EVENT_COUNT; i++) {
+		e = sse_event_get(supported_events[i]);
+
+		if (e->attrs.hartid != current_hartid())
+			continue;
+
+		if (sse_event_state(e) > SBI_SSE_STATE_REGISTERED) {
+			sbi_printf("Event %d in invalid state at exit", i);
+			sse_event_set_state(e, SBI_SSE_STATE_UNUSED);
+		}
+	}
+}
diff --git a/lib/sbi/sbi_trap.c b/lib/sbi/sbi_trap.c
index 175560f..624b45e 100644
--- a/lib/sbi/sbi_trap.c
+++ b/lib/sbi/sbi_trap.c
@@ -20,6 +20,7 @@
 #include <sbi/sbi_trap_ldst.h>
 #include <sbi/sbi_pmu.h>
 #include <sbi/sbi_scratch.h>
+#include <sbi/sbi_sse.h>
 #include <sbi/sbi_timer.h>
 #include <sbi/sbi_trap.h>
 
@@ -337,6 +338,10 @@ struct sbi_trap_context *sbi_trap_handler(struct sbi_trap_context *tcntx)
 trap_done:
 	if (rc)
 		sbi_trap_error(msg, rc, tcntx);
+
+	if (((regs->mstatus & MSTATUS_MPP) >> MSTATUS_MPP_SHIFT) != PRV_M)
+		sbi_sse_process_pending_events(regs);
+
 	sbi_trap_set_context(scratch, tcntx->prev_context);
 	return tcntx;
 }
-- 
2.43.0




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