xref: /openbmc/qemu/include/exec/translator.h (revision d525f73f)
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  * gen_intermediate_code
31  * @cpu: cpu context
32  * @tb: translation block
33  * @max_insns: max number of instructions to translate
34  * @pc: guest virtual program counter address
35  * @host_pc: host physical program counter address
36  *
37  * This function must be provided by the target, which should create
38  * the target-specific DisasContext, and then invoke translator_loop.
39  */
40 void gen_intermediate_code(CPUState *cpu, TranslationBlock *tb, int max_insns,
41                            target_ulong pc, void *host_pc);
42 
43 /**
44  * DisasJumpType:
45  * @DISAS_NEXT: Next instruction in program order.
46  * @DISAS_TOO_MANY: Too many instructions translated.
47  * @DISAS_NORETURN: Following code is dead.
48  * @DISAS_TARGET_*: Start of target-specific conditions.
49  *
50  * What instruction to disassemble next.
51  */
52 typedef enum DisasJumpType {
53     DISAS_NEXT,
54     DISAS_TOO_MANY,
55     DISAS_NORETURN,
56     DISAS_TARGET_0,
57     DISAS_TARGET_1,
58     DISAS_TARGET_2,
59     DISAS_TARGET_3,
60     DISAS_TARGET_4,
61     DISAS_TARGET_5,
62     DISAS_TARGET_6,
63     DISAS_TARGET_7,
64     DISAS_TARGET_8,
65     DISAS_TARGET_9,
66     DISAS_TARGET_10,
67     DISAS_TARGET_11,
68 } DisasJumpType;
69 
70 /**
71  * DisasContextBase:
72  * @tb: Translation block for this disassembly.
73  * @pc_first: Address of first guest instruction in this TB.
74  * @pc_next: Address of next guest instruction in this TB (current during
75  *           disassembly).
76  * @is_jmp: What instruction to disassemble next.
77  * @num_insns: Number of translated instructions (including current).
78  * @max_insns: Maximum number of instructions to be translated in this TB.
79  * @singlestep_enabled: "Hardware" single stepping enabled.
80  *
81  * Architecture-agnostic disassembly context.
82  */
83 typedef struct DisasContextBase {
84     TranslationBlock *tb;
85     target_ulong pc_first;
86     target_ulong pc_next;
87     DisasJumpType is_jmp;
88     int num_insns;
89     int max_insns;
90     bool singlestep_enabled;
91     void *host_addr[2];
92 } DisasContextBase;
93 
94 /**
95  * TranslatorOps:
96  * @init_disas_context:
97  *      Initialize the target-specific portions of DisasContext struct.
98  *      The generic DisasContextBase has already been initialized.
99  *
100  * @tb_start:
101  *      Emit any code required before the start of the main loop,
102  *      after the generic gen_tb_start().
103  *
104  * @insn_start:
105  *      Emit the tcg_gen_insn_start opcode.
106  *
107  * @translate_insn:
108  *      Disassemble one instruction and set db->pc_next for the start
109  *      of the following instruction.  Set db->is_jmp as necessary to
110  *      terminate the main loop.
111  *
112  * @tb_stop:
113  *      Emit any opcodes required to exit the TB, based on db->is_jmp.
114  *
115  * @disas_log:
116  *      Print instruction disassembly to log.
117  */
118 typedef struct TranslatorOps {
119     void (*init_disas_context)(DisasContextBase *db, CPUState *cpu);
120     void (*tb_start)(DisasContextBase *db, CPUState *cpu);
121     void (*insn_start)(DisasContextBase *db, CPUState *cpu);
122     void (*translate_insn)(DisasContextBase *db, CPUState *cpu);
123     void (*tb_stop)(DisasContextBase *db, CPUState *cpu);
124     void (*disas_log)(const DisasContextBase *db, CPUState *cpu, FILE *f);
125 } TranslatorOps;
126 
127 /**
128  * translator_loop:
129  * @cpu: Target vCPU.
130  * @tb: Translation block.
131  * @max_insns: Maximum number of insns to translate.
132  * @pc: guest virtual program counter address
133  * @host_pc: host physical program counter address
134  * @ops: Target-specific operations.
135  * @db: Disassembly context.
136  *
137  * Generic translator loop.
138  *
139  * Translation will stop in the following cases (in order):
140  * - When is_jmp set by #TranslatorOps::breakpoint_check.
141  *   - set to DISAS_TOO_MANY exits after translating one more insn
142  *   - set to any other value than DISAS_NEXT exits immediately.
143  * - When is_jmp set by #TranslatorOps::translate_insn.
144  *   - set to any value other than DISAS_NEXT exits immediately.
145  * - When the TCG operation buffer is full.
146  * - When single-stepping is enabled (system-wide or on the current vCPU).
147  * - When too many instructions have been translated.
148  */
149 void translator_loop(CPUState *cpu, TranslationBlock *tb, int max_insns,
150                      target_ulong pc, void *host_pc,
151                      const TranslatorOps *ops, DisasContextBase *db);
152 
153 void translator_loop_temp_check(DisasContextBase *db);
154 
155 /**
156  * translator_use_goto_tb
157  * @db: Disassembly context
158  * @dest: target pc of the goto
159  *
160  * Return true if goto_tb is allowed between the current TB
161  * and the destination PC.
162  */
163 bool translator_use_goto_tb(DisasContextBase *db, target_ulong dest);
164 
165 /*
166  * Translator Load Functions
167  *
168  * These are intended to replace the direct usage of the cpu_ld*_code
169  * functions and are mandatory for front-ends that have been migrated
170  * to the common translator_loop. These functions are only intended
171  * to be called from the translation stage and should not be called
172  * from helper functions. Those functions should be converted to encode
173  * the relevant information at translation time.
174  */
175 
176 uint8_t translator_ldub(CPUArchState *env, DisasContextBase *db, abi_ptr pc);
177 uint16_t translator_lduw(CPUArchState *env, DisasContextBase *db, abi_ptr pc);
178 uint32_t translator_ldl(CPUArchState *env, DisasContextBase *db, abi_ptr pc);
179 uint64_t translator_ldq(CPUArchState *env, DisasContextBase *db, abi_ptr pc);
180 
181 static inline uint16_t
182 translator_lduw_swap(CPUArchState *env, DisasContextBase *db,
183                      abi_ptr pc, bool do_swap)
184 {
185     uint16_t ret = translator_lduw(env, db, pc);
186     if (do_swap) {
187         ret = bswap16(ret);
188     }
189     return ret;
190 }
191 
192 static inline uint32_t
193 translator_ldl_swap(CPUArchState *env, DisasContextBase *db,
194                     abi_ptr pc, bool do_swap)
195 {
196     uint32_t ret = translator_ldl(env, db, pc);
197     if (do_swap) {
198         ret = bswap32(ret);
199     }
200     return ret;
201 }
202 
203 static inline uint64_t
204 translator_ldq_swap(CPUArchState *env, DisasContextBase *db,
205                     abi_ptr pc, bool do_swap)
206 {
207     uint64_t ret = translator_ldq(env, db, pc);
208     if (do_swap) {
209         ret = bswap64(ret);
210     }
211     return ret;
212 }
213 
214 /*
215  * Return whether addr is on the same page as where disassembly started.
216  * Translators can use this to enforce the rule that only single-insn
217  * translation blocks are allowed to cross page boundaries.
218  */
219 static inline bool is_same_page(const DisasContextBase *db, target_ulong addr)
220 {
221     return ((addr ^ db->pc_first) & TARGET_PAGE_MASK) == 0;
222 }
223 
224 #endif /* EXEC__TRANSLATOR_H */
225