summaryrefslogtreecommitdiff
path: root/lib/sbi/sbi_illegal_insn.c
blob: 554183867ac03c14a46a2a49af3639698ece3bd6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
/*
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2019 Western Digital Corporation or its affiliates.
 *
 * Authors:
 *   Anup Patel <anup.patel@wdc.com>
 */

#include <sbi/riscv_asm.h>
#include <sbi/riscv_encoding.h>
#include <sbi/riscv_unpriv.h>
#include <sbi/sbi_bits.h>
#include <sbi/sbi_emulate_csr.h>
#include <sbi/sbi_error.h>
#include <sbi/sbi_illegal_insn.h>
#include <sbi/sbi_trap.h>

typedef int (*illegal_insn_func)(ulong insn, u32 hartid, ulong mcause,
				 struct sbi_trap_regs *regs,
				 struct sbi_scratch *scratch);

static int truly_illegal_insn(ulong insn, u32 hartid, ulong mcause,
			      struct sbi_trap_regs *regs,
			      struct sbi_scratch *scratch)
{
	return sbi_trap_redirect(regs, scratch, regs->mepc, mcause, insn);
}

static int system_opcode_insn(ulong insn, u32 hartid, ulong mcause,
			      struct sbi_trap_regs *regs,
			      struct sbi_scratch *scratch)
{
	int do_write, rs1_num = (insn >> 15) & 0x1f;
	ulong rs1_val = GET_RS1(insn, regs);
	int csr_num   = (u32)insn >> 20;
	ulong csr_val, new_csr_val;

	if (sbi_emulate_csr_read(csr_num, hartid, regs->mstatus, scratch,
				 &csr_val))
		return truly_illegal_insn(insn, hartid, mcause, regs, scratch);

	do_write = rs1_num;
	switch (GET_RM(insn)) {
	case 1:
		new_csr_val = rs1_val;
		do_write    = 1;
		break;
	case 2:
		new_csr_val = csr_val | rs1_val;
		break;
	case 3:
		new_csr_val = csr_val & ~rs1_val;
		break;
	case 5:
		new_csr_val = rs1_num;
		do_write    = 1;
		break;
	case 6:
		new_csr_val = csr_val | rs1_num;
		break;
	case 7:
		new_csr_val = csr_val & ~rs1_num;
		break;
	default:
		return truly_illegal_insn(insn, hartid, mcause, regs, scratch);
	};

	if (do_write && sbi_emulate_csr_write(csr_num, hartid, regs->mstatus,
					      scratch, new_csr_val))
		return truly_illegal_insn(insn, hartid, mcause, regs, scratch);

	SET_RD(insn, regs, csr_val);

	regs->mepc += 4;

	return 0;
}

static illegal_insn_func illegal_insn_table[32] = {
	truly_illegal_insn, /* 0 */
	truly_illegal_insn, /* 1 */
	truly_illegal_insn, /* 2 */
	truly_illegal_insn, /* 3 */
	truly_illegal_insn, /* 4 */
	truly_illegal_insn, /* 5 */
	truly_illegal_insn, /* 6 */
	truly_illegal_insn, /* 7 */
	truly_illegal_insn, /* 8 */
	truly_illegal_insn, /* 9 */
	truly_illegal_insn, /* 10 */
	truly_illegal_insn, /* 11 */
	truly_illegal_insn, /* 12 */
	truly_illegal_insn, /* 13 */
	truly_illegal_insn, /* 14 */
	truly_illegal_insn, /* 15 */
	truly_illegal_insn, /* 16 */
	truly_illegal_insn, /* 17 */
	truly_illegal_insn, /* 18 */
	truly_illegal_insn, /* 19 */
	truly_illegal_insn, /* 20 */
	truly_illegal_insn, /* 21 */
	truly_illegal_insn, /* 22 */
	truly_illegal_insn, /* 23 */
	truly_illegal_insn, /* 24 */
	truly_illegal_insn, /* 25 */
	truly_illegal_insn, /* 26 */
	truly_illegal_insn, /* 27 */
	system_opcode_insn, /* 28 */
	truly_illegal_insn, /* 29 */
	truly_illegal_insn, /* 30 */
	truly_illegal_insn  /* 31 */
};

int sbi_illegal_insn_handler(u32 hartid, ulong mcause,
			     struct sbi_trap_regs *regs,
			     struct sbi_scratch *scratch)
{
	ulong insn = csr_read(mbadaddr);

	if (unlikely((insn & 3) != 3)) {
		if (insn == 0)
			insn = get_insn(regs->mepc, NULL);
		if ((insn & 3) != 3)
			return truly_illegal_insn(insn, hartid, mcause, regs,
						  scratch);
	}

	return illegal_insn_table[(insn & 0x7c) >> 2](insn, hartid, mcause,
						      regs, scratch);
}