xref: /openbmc/qemu/include/exec/translator.h (revision ae3c12a0) 
1 /*
2  * Generic intermediate code generation.
3  *
4  * Copyright (C) 2016-2017 Lluís Vilanova <vilanova@ac.upc.edu>
5  *
6  * This work is licensed under the terms of the GNU GPL, version 2 or later.
7  * See the COPYING file in the top-level directory.
8  */
9 
10 #ifndef EXEC__TRANSLATOR_H
11 #define EXEC__TRANSLATOR_H
12 
13 /*
14  * Include this header from a target-specific file, and add a
15  *
16  *     DisasContextBase base;
17  *
18  * member in your target-specific DisasContext.
19  */
20 
21 
22 #include "exec/exec-all.h"
23 #include "tcg/tcg.h"
24 
25 
26 /**
27  * DisasJumpType:
28  * @DISAS_NEXT: Next instruction in program order.
29  * @DISAS_TOO_MANY: Too many instructions translated.
30  * @DISAS_NORETURN: Following code is dead.
31  * @DISAS_TARGET_*: Start of target-specific conditions.
32  *
33  * What instruction to disassemble next.
34  */
35 typedef enum DisasJumpType {
36     DISAS_NEXT,
37     DISAS_TOO_MANY,
38     DISAS_NORETURN,
39     DISAS_TARGET_0,
40     DISAS_TARGET_1,
41     DISAS_TARGET_2,
42     DISAS_TARGET_3,
43     DISAS_TARGET_4,
44     DISAS_TARGET_5,
45     DISAS_TARGET_6,
46     DISAS_TARGET_7,
47     DISAS_TARGET_8,
48     DISAS_TARGET_9,
49     DISAS_TARGET_10,
50     DISAS_TARGET_11,
51 } DisasJumpType;
52 
53 /**
54  * DisasContextBase:
55  * @tb: Translation block for this disassembly.
56  * @pc_first: Address of first guest instruction in this TB.
57  * @pc_next: Address of next guest instruction in this TB (current during
58  *           disassembly).
59  * @is_jmp: What instruction to disassemble next.
60  * @num_insns: Number of translated instructions (including current).
61  * @max_insns: Maximum number of instructions to be translated in this TB.
62  * @singlestep_enabled: "Hardware" single stepping enabled.
63  *
64  * Architecture-agnostic disassembly context.
65  */
66 typedef struct DisasContextBase {
67     TranslationBlock *tb;
68     target_ulong pc_first;
69     target_ulong pc_next;
70     DisasJumpType is_jmp;
71     int num_insns;
72     int max_insns;
73     bool singlestep_enabled;
74 } DisasContextBase;
75 
76 /**
77  * TranslatorOps:
78  * @init_disas_context:
79  *      Initialize the target-specific portions of DisasContext struct.
80  *      The generic DisasContextBase has already been initialized.
81  *
82  * @tb_start:
83  *      Emit any code required before the start of the main loop,
84  *      after the generic gen_tb_start().
85  *
86  * @insn_start:
87  *      Emit the tcg_gen_insn_start opcode.
88  *
89  * @breakpoint_check:
90  *      When called, the breakpoint has already been checked to match the PC,
91  *      but the target may decide the breakpoint missed the address
92  *      (e.g., due to conditions encoded in their flags).  Return true to
93  *      indicate that the breakpoint did hit, in which case no more breakpoints
94  *      are checked.  If the breakpoint did hit, emit any code required to
95  *      signal the exception, and set db->is_jmp as necessary to terminate
96  *      the main loop.
97  *
98  * @translate_insn:
99  *      Disassemble one instruction and set db->pc_next for the start
100  *      of the following instruction.  Set db->is_jmp as necessary to
101  *      terminate the main loop.
102  *
103  * @tb_stop:
104  *      Emit any opcodes required to exit the TB, based on db->is_jmp.
105  *
106  * @disas_log:
107  *      Print instruction disassembly to log.
108  */
109 typedef struct TranslatorOps {
110     void (*init_disas_context)(DisasContextBase *db, CPUState *cpu);
111     void (*tb_start)(DisasContextBase *db, CPUState *cpu);
112     void (*insn_start)(DisasContextBase *db, CPUState *cpu);
113     bool (*breakpoint_check)(DisasContextBase *db, CPUState *cpu,
114                              const CPUBreakpoint *bp);
115     void (*translate_insn)(DisasContextBase *db, CPUState *cpu);
116     void (*tb_stop)(DisasContextBase *db, CPUState *cpu);
117     void (*disas_log)(const DisasContextBase *db, CPUState *cpu);
118 } TranslatorOps;
119 
120 /**
121  * translator_loop:
122  * @ops: Target-specific operations.
123  * @db: Disassembly context.
124  * @cpu: Target vCPU.
125  * @tb: Translation block.
126  * @max_insns: Maximum number of insns to translate.
127  *
128  * Generic translator loop.
129  *
130  * Translation will stop in the following cases (in order):
131  * - When is_jmp set by #TranslatorOps::breakpoint_check.
132  *   - set to DISAS_TOO_MANY exits after translating one more insn
133  *   - set to any other value than DISAS_NEXT exits immediately.
134  * - When is_jmp set by #TranslatorOps::translate_insn.
135  *   - set to any value other than DISAS_NEXT exits immediately.
136  * - When the TCG operation buffer is full.
137  * - When single-stepping is enabled (system-wide or on the current vCPU).
138  * - When too many instructions have been translated.
139  */
140 void translator_loop(const TranslatorOps *ops, DisasContextBase *db,
141                      CPUState *cpu, TranslationBlock *tb, int max_insns);
142 
143 void translator_loop_temp_check(DisasContextBase *db);
144 
145 #endif /* EXEC__TRANSLATOR_H */
146