1 /*
2  * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
3  *
4  * SPDX-License-Identifier: BSD-3-Clause
5  */
6 
7 #ifndef EHF_H
8 #define EHF_H
9 
10 #ifndef __ASSEMBLER__
11 
12 #include <cdefs.h>
13 #include <stdint.h>
14 
15 #include <lib/utils_def.h>
16 
17 /* Valid priorities set bit 0 of the priority handler. */
18 #define EHF_PRI_VALID_	BIT(0)
19 
20 /* Marker for no handler registered for a valid priority */
21 #define EHF_NO_HANDLER_	(0U | EHF_PRI_VALID_)
22 
23 /* Extract the specified number of top bits from 7 lower bits of priority */
24 #define EHF_PRI_TO_IDX(pri, plat_bits) \
25 	((((unsigned) (pri)) & 0x7fu) >> (7u - (plat_bits)))
26 
27 /* Install exception priority descriptor at a suitable index */
28 #define EHF_PRI_DESC(plat_bits, priority) \
29 	[EHF_PRI_TO_IDX(priority, plat_bits)] = { \
30 		.ehf_handler = EHF_NO_HANDLER_, \
31 	}
32 
33 /* Macro for platforms to regiter its exception priorities */
34 #define EHF_REGISTER_PRIORITIES(priorities, num, bits) \
35 	const ehf_priorities_t exception_data = { \
36 		.num_priorities = (num), \
37 		.ehf_priorities = (priorities), \
38 		.pri_bits = (bits), \
39 	}
40 
41 /*
42  * Priority stack, managed as a bitmap.
43  *
44  * Currently only supports 32 priority levels, allowing platforms to use up to 5
45  * top bits of priority. But the type can be changed to uint64_t should need
46  * arise to support 64 priority levels, allowing platforms to use up to 6 top
47  * bits of priority.
48  */
49 typedef uint32_t ehf_pri_bits_t;
50 
51 /*
52  * Per-PE exception data. The data for each PE is kept as a per-CPU data field.
53  * See cpu_data.h.
54  */
55 typedef struct {
56 	ehf_pri_bits_t active_pri_bits;
57 
58 	/* Priority mask value before any priority levels were active */
59 	uint8_t init_pri_mask;
60 
61 	/* Non-secure priority mask value stashed during Secure execution */
62 	uint8_t ns_pri_mask;
63 } __aligned(sizeof(uint64_t)) pe_exc_data_t;
64 
65 typedef int (*ehf_handler_t)(uint32_t intr_raw, uint32_t flags, void *handle,
66 		void *cookie);
67 
68 typedef struct ehf_pri_desc {
69 	/*
70 	 * 4-byte-aligned exception handler. Bit 0 indicates the corresponding
71 	 * priority level is valid. This is effectively of ehf_handler_t type,
72 	 * but left as uintptr_t in order to make pointer arithmetic convenient.
73 	 */
74 	uintptr_t ehf_handler;
75 } ehf_pri_desc_t;
76 
77 typedef struct ehf_priority_type {
78 	ehf_pri_desc_t *ehf_priorities;
79 	unsigned int num_priorities;
80 	unsigned int pri_bits;
81 } ehf_priorities_t;
82 
83 void ehf_init(void);
84 void ehf_activate_priority(unsigned int priority);
85 void ehf_deactivate_priority(unsigned int priority);
86 void ehf_register_priority_handler(unsigned int pri, ehf_handler_t handler);
87 void ehf_allow_ns_preemption(uint64_t preempt_ret_code);
88 unsigned int ehf_is_ns_preemption_allowed(void);
89 
90 #endif /* __ASSEMBLER__ */
91 
92 #endif /* EHF_H */
93