xref: /openbmc/qemu/include/exec/translator.h (revision 9d81b2d2) 
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  * @singlestep_enabled: "Hardware" single stepping enabled.
62  *
63  * Architecture-agnostic disassembly context.
64  */
65 typedef struct DisasContextBase {
66     TranslationBlock *tb;
67     target_ulong pc_first;
68     target_ulong pc_next;
69     DisasJumpType is_jmp;
70     unsigned int num_insns;
71     bool singlestep_enabled;
72 } DisasContextBase;
73 
74 /**
75  * TranslatorOps:
76  * @init_disas_context:
77  *      Initialize the target-specific portions of DisasContext struct.
78  *      The generic DisasContextBase has already been initialized.
79  *      Return max_insns, modified as necessary by db->tb->flags.
80  *
81  * @tb_start:
82  *      Emit any code required before the start of the main loop,
83  *      after the generic gen_tb_start().
84  *
85  * @insn_start:
86  *      Emit the tcg_gen_insn_start opcode.
87  *
88  * @breakpoint_check:
89  *      When called, the breakpoint has already been checked to match the PC,
90  *      but the target may decide the breakpoint missed the address
91  *      (e.g., due to conditions encoded in their flags).  Return true to
92  *      indicate that the breakpoint did hit, in which case no more breakpoints
93  *      are checked.  If the breakpoint did hit, emit any code required to
94  *      signal the exception, and set db->is_jmp as necessary to terminate
95  *      the main loop.
96  *
97  * @translate_insn:
98  *      Disassemble one instruction and set db->pc_next for the start
99  *      of the following instruction.  Set db->is_jmp as necessary to
100  *      terminate the main loop.
101  *
102  * @tb_stop:
103  *      Emit any opcodes required to exit the TB, based on db->is_jmp.
104  *
105  * @disas_log:
106  *      Print instruction disassembly to log.
107  */
108 typedef struct TranslatorOps {
109     int (*init_disas_context)(DisasContextBase *db, CPUState *cpu,
110                               int max_insns);
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  *
127  * Generic translator loop.
128  *
129  * Translation will stop in the following cases (in order):
130  * - When is_jmp set by #TranslatorOps::breakpoint_check.
131  *   - set to DISAS_TOO_MANY exits after translating one more insn
132  *   - set to any other value than DISAS_NEXT exits immediately.
133  * - When is_jmp set by #TranslatorOps::translate_insn.
134  *   - set to any value other than DISAS_NEXT exits immediately.
135  * - When the TCG operation buffer is full.
136  * - When single-stepping is enabled (system-wide or on the current vCPU).
137  * - When too many instructions have been translated.
138  */
139 void translator_loop(const TranslatorOps *ops, DisasContextBase *db,
140                      CPUState *cpu, TranslationBlock *tb);
141 
142 void translator_loop_temp_check(DisasContextBase *db);
143 
144 #endif  /* EXEC__TRANSLATOR_H */
145