1 /*
2 * Copyright (C) 2014-2020 Paul Cercueil <paul@crapouillou.net>
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 */
14
15 #include "config.h"
16
17 #if ENABLE_DISASSEMBLER
18 #include <dis-asm.h>
19 #endif
20 #include <stdbool.h>
21 #include <stdlib.h>
22 #include <string.h>
23
24 #include "debug.h"
25 #include "disassembler.h"
26 #include "lightrec-private.h"
27 #include "memmanager.h"
28
is_unconditional_jump(const struct opcode * op)29 static bool is_unconditional_jump(const struct opcode *op)
30 {
31 switch (op->i.op) {
32 case OP_SPECIAL:
33 return op->r.op == OP_SPECIAL_JR || op->r.op == OP_SPECIAL_JALR;
34 case OP_J:
35 case OP_JAL:
36 return true;
37 case OP_BEQ:
38 case OP_BLEZ:
39 return op->i.rs == op->i.rt;
40 case OP_REGIMM:
41 return (op->r.rt == OP_REGIMM_BGEZ ||
42 op->r.rt == OP_REGIMM_BGEZAL) && op->i.rs == 0;
43 default:
44 return false;
45 }
46 }
47
is_syscall(const struct opcode * op)48 static bool is_syscall(const struct opcode *op)
49 {
50 return (op->i.op == OP_SPECIAL && (op->r.op == OP_SPECIAL_SYSCALL ||
51 op->r.op == OP_SPECIAL_BREAK)) ||
52 (op->i.op == OP_CP0 && (op->r.rs == OP_CP0_MTC0 ||
53 op->r.rs == OP_CP0_CTC0) &&
54 (op->r.rd == 12 || op->r.rd == 13));
55 }
56
lightrec_free_opcode_list(struct lightrec_state * state,struct opcode * list)57 void lightrec_free_opcode_list(struct lightrec_state *state, struct opcode *list)
58 {
59 struct opcode *next;
60
61 while (list) {
62 next = list->next;
63 lightrec_free(state, MEM_FOR_IR, sizeof(*list), list);
64 list = next;
65 }
66 }
67
lightrec_disassemble(struct lightrec_state * state,const u32 * src,unsigned int * len)68 struct opcode * lightrec_disassemble(struct lightrec_state *state,
69 const u32 *src, unsigned int *len)
70 {
71 struct opcode *head = NULL;
72 bool stop_next = false;
73 struct opcode *curr, *last;
74 unsigned int i;
75
76 for (i = 0, last = NULL; ; i++, last = curr) {
77 curr = lightrec_calloc(state, MEM_FOR_IR, sizeof(*curr));
78 if (!curr) {
79 pr_err("Unable to allocate memory\n");
80 lightrec_free_opcode_list(state, head);
81 return NULL;
82 }
83
84 if (!last)
85 head = curr;
86 else
87 last->next = curr;
88
89 /* TODO: Take care of endianness */
90 curr->opcode = LE32TOH(*src++);
91 curr->offset = i;
92
93 /* NOTE: The block disassembly ends after the opcode that
94 * follows an unconditional jump (delay slot) */
95 if (stop_next || is_syscall(curr))
96 break;
97 else if (is_unconditional_jump(curr))
98 stop_next = true;
99 }
100
101 if (len)
102 *len = (i + 1) * sizeof(u32);
103
104 return head;
105 }
106
lightrec_cycles_of_opcode(union code code)107 unsigned int lightrec_cycles_of_opcode(union code code)
108 {
109 switch (code.i.op) {
110 case OP_META_REG_UNLOAD:
111 case OP_META_SYNC:
112 return 0;
113 default:
114 return 2;
115 }
116 }
117
118 #if ENABLE_DISASSEMBLER
lightrec_print_disassembly(const struct block * block,const u32 * code,unsigned int length)119 void lightrec_print_disassembly(const struct block *block,
120 const u32 *code, unsigned int length)
121 {
122 struct disassemble_info info;
123 unsigned int i;
124
125 memset(&info, 0, sizeof(info));
126 init_disassemble_info(&info, stdout, (fprintf_ftype) fprintf);
127
128 info.buffer = (bfd_byte *) code;
129 info.buffer_vma = (bfd_vma)(uintptr_t) code;
130 info.buffer_length = length;
131 info.flavour = bfd_target_unknown_flavour;
132 info.arch = bfd_arch_mips;
133 info.mach = bfd_mach_mips3000;
134 disassemble_init_for_target(&info);
135
136 for (i = 0; i < length; i += 4) {
137 void print_insn_little_mips(bfd_vma, struct disassemble_info *);
138 putc('\t', stdout);
139 print_insn_little_mips((bfd_vma)(uintptr_t) code++, &info);
140 putc('\n', stdout);
141 }
142 }
143 #endif
144