xref: /openbmc/qemu/include/exec/translator.h (revision 4d84bb6c)
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 "qemu/bswap.h"
23 #include "exec/exec-all.h"
24 #include "exec/cpu_ldst.h"
25 #include "exec/plugin-gen.h"
26 #include "exec/translate-all.h"
27 #include "tcg/tcg.h"
28 
29 
30 /**
31  * DisasJumpType:
32  * @DISAS_NEXT: Next instruction in program order.
33  * @DISAS_TOO_MANY: Too many instructions translated.
34  * @DISAS_NORETURN: Following code is dead.
35  * @DISAS_TARGET_*: Start of target-specific conditions.
36  *
37  * What instruction to disassemble next.
38  */
39 typedef enum DisasJumpType {
40     DISAS_NEXT,
41     DISAS_TOO_MANY,
42     DISAS_NORETURN,
43     DISAS_TARGET_0,
44     DISAS_TARGET_1,
45     DISAS_TARGET_2,
46     DISAS_TARGET_3,
47     DISAS_TARGET_4,
48     DISAS_TARGET_5,
49     DISAS_TARGET_6,
50     DISAS_TARGET_7,
51     DISAS_TARGET_8,
52     DISAS_TARGET_9,
53     DISAS_TARGET_10,
54     DISAS_TARGET_11,
55 } DisasJumpType;
56 
57 /**
58  * DisasContextBase:
59  * @tb: Translation block for this disassembly.
60  * @pc_first: Address of first guest instruction in this TB.
61  * @pc_next: Address of next guest instruction in this TB (current during
62  *           disassembly).
63  * @is_jmp: What instruction to disassemble next.
64  * @num_insns: Number of translated instructions (including current).
65  * @max_insns: Maximum number of instructions to be translated in this TB.
66  * @singlestep_enabled: "Hardware" single stepping enabled.
67  *
68  * Architecture-agnostic disassembly context.
69  */
70 typedef struct DisasContextBase {
71     const TranslationBlock *tb;
72     target_ulong pc_first;
73     target_ulong pc_next;
74     DisasJumpType is_jmp;
75     int num_insns;
76     int max_insns;
77     bool singlestep_enabled;
78 #ifdef CONFIG_USER_ONLY
79     /*
80      * Guest address of the last byte of the last protected page.
81      *
82      * Pages containing the translated instructions are made non-writable in
83      * order to achieve consistency in case another thread is modifying the
84      * code while translate_insn() fetches the instruction bytes piecemeal.
85      * Such writer threads are blocked on mmap_lock() in page_unprotect().
86      */
87     target_ulong page_protect_end;
88 #endif
89 } DisasContextBase;
90 
91 /**
92  * TranslatorOps:
93  * @init_disas_context:
94  *      Initialize the target-specific portions of DisasContext struct.
95  *      The generic DisasContextBase has already been initialized.
96  *
97  * @tb_start:
98  *      Emit any code required before the start of the main loop,
99  *      after the generic gen_tb_start().
100  *
101  * @insn_start:
102  *      Emit the tcg_gen_insn_start opcode.
103  *
104  * @translate_insn:
105  *      Disassemble one instruction and set db->pc_next for the start
106  *      of the following instruction.  Set db->is_jmp as necessary to
107  *      terminate the main loop.
108  *
109  * @tb_stop:
110  *      Emit any opcodes required to exit the TB, based on db->is_jmp.
111  *
112  * @disas_log:
113  *      Print instruction disassembly to log.
114  */
115 typedef struct TranslatorOps {
116     void (*init_disas_context)(DisasContextBase *db, CPUState *cpu);
117     void (*tb_start)(DisasContextBase *db, CPUState *cpu);
118     void (*insn_start)(DisasContextBase *db, CPUState *cpu);
119     void (*translate_insn)(DisasContextBase *db, CPUState *cpu);
120     void (*tb_stop)(DisasContextBase *db, CPUState *cpu);
121     void (*disas_log)(const DisasContextBase *db, CPUState *cpu, FILE *f);
122 } TranslatorOps;
123 
124 /**
125  * translator_loop:
126  * @ops: Target-specific operations.
127  * @db: Disassembly context.
128  * @cpu: Target vCPU.
129  * @tb: Translation block.
130  * @max_insns: Maximum number of insns to translate.
131  *
132  * Generic translator loop.
133  *
134  * Translation will stop in the following cases (in order):
135  * - When is_jmp set by #TranslatorOps::breakpoint_check.
136  *   - set to DISAS_TOO_MANY exits after translating one more insn
137  *   - set to any other value than DISAS_NEXT exits immediately.
138  * - When is_jmp set by #TranslatorOps::translate_insn.
139  *   - set to any value other than DISAS_NEXT exits immediately.
140  * - When the TCG operation buffer is full.
141  * - When single-stepping is enabled (system-wide or on the current vCPU).
142  * - When too many instructions have been translated.
143  */
144 void translator_loop(const TranslatorOps *ops, DisasContextBase *db,
145                      CPUState *cpu, TranslationBlock *tb, int max_insns);
146 
147 void translator_loop_temp_check(DisasContextBase *db);
148 
149 /**
150  * translator_use_goto_tb
151  * @db: Disassembly context
152  * @dest: target pc of the goto
153  *
154  * Return true if goto_tb is allowed between the current TB
155  * and the destination PC.
156  */
157 bool translator_use_goto_tb(DisasContextBase *db, target_ulong dest);
158 
159 /*
160  * Translator Load Functions
161  *
162  * These are intended to replace the direct usage of the cpu_ld*_code
163  * functions and are mandatory for front-ends that have been migrated
164  * to the common translator_loop. These functions are only intended
165  * to be called from the translation stage and should not be called
166  * from helper functions. Those functions should be converted to encode
167  * the relevant information at translation time.
168  */
169 
170 #define GEN_TRANSLATOR_LD(fullname, type, load_fn, swap_fn)             \
171     type fullname ## _swap(CPUArchState *env, DisasContextBase *dcbase, \
172                            abi_ptr pc, bool do_swap);                   \
173     static inline type fullname(CPUArchState *env,                      \
174                                 DisasContextBase *dcbase, abi_ptr pc)   \
175     {                                                                   \
176         return fullname ## _swap(env, dcbase, pc, false);               \
177     }
178 
179 #define FOR_EACH_TRANSLATOR_LD(F)                                       \
180     F(translator_ldub, uint8_t, cpu_ldub_code, /* no swap */)           \
181     F(translator_ldsw, int16_t, cpu_ldsw_code, bswap16)                 \
182     F(translator_lduw, uint16_t, cpu_lduw_code, bswap16)                \
183     F(translator_ldl, uint32_t, cpu_ldl_code, bswap32)                  \
184     F(translator_ldq, uint64_t, cpu_ldq_code, bswap64)
185 
186 FOR_EACH_TRANSLATOR_LD(GEN_TRANSLATOR_LD)
187 
188 #undef GEN_TRANSLATOR_LD
189 
190 #endif /* EXEC__TRANSLATOR_H */
191