1 files changed, 92 insertions, 0 deletions
diff --git a/include/bl31/ehf.h b/include/bl31/ehf.h
new file mode 100644
index 0000000..c13d28c
--- /dev/null
+++ b/include/bl31/ehf.h
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef EHF_H
+#define EHF_H
+
+#ifndef __ASSEMBLER__
+
+#include <cdefs.h>
+#include <stdint.h>
+
+#include <lib/utils_def.h>
+
+/* Valid priorities set bit 0 of the priority handler. */
+#define EHF_PRI_VALID_	BIT(0)
+
+/* Marker for no handler registered for a valid priority */
+#define EHF_NO_HANDLER_	(0U | EHF_PRI_VALID_)
+
+/* Extract the specified number of top bits from 7 lower bits of priority */
+#define EHF_PRI_TO_IDX(pri, plat_bits) \
+	((((unsigned) (pri)) & 0x7fu) >> (7u - (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_priority_type {
+	ehf_pri_desc_t *ehf_priorities;
+	unsigned int num_priorities;
+	unsigned 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(uint64_t preempt_ret_code);
+unsigned int ehf_is_ns_preemption_allowed(void);
+
+#endif /* __ASSEMBLER__ */
+
+#endif /* EHF_H */