xref: /openbmc/qemu/include/exec/translator.h (revision 646b5378)
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 #include "qemu/bswap.h"
22 #include "exec/vaddr.h"
23 
24 /**
25  * gen_intermediate_code
26  * @cpu: cpu context
27  * @tb: translation block
28  * @max_insns: max number of instructions to translate
29  * @pc: guest virtual program counter address
30  * @host_pc: host physical program counter address
31  *
32  * This function must be provided by the target, which should create
33  * the target-specific DisasContext, and then invoke translator_loop.
34  */
35 void gen_intermediate_code(CPUState *cpu, TranslationBlock *tb, int *max_insns,
36                            vaddr pc, void *host_pc);
37 
38 /**
39  * DisasJumpType:
40  * @DISAS_NEXT: Next instruction in program order.
41  * @DISAS_TOO_MANY: Too many instructions translated.
42  * @DISAS_NORETURN: Following code is dead.
43  * @DISAS_TARGET_*: Start of target-specific conditions.
44  *
45  * What instruction to disassemble next.
46  */
47 typedef enum DisasJumpType {
48     DISAS_NEXT,
49     DISAS_TOO_MANY,
50     DISAS_NORETURN,
51     DISAS_TARGET_0,
52     DISAS_TARGET_1,
53     DISAS_TARGET_2,
54     DISAS_TARGET_3,
55     DISAS_TARGET_4,
56     DISAS_TARGET_5,
57     DISAS_TARGET_6,
58     DISAS_TARGET_7,
59     DISAS_TARGET_8,
60     DISAS_TARGET_9,
61     DISAS_TARGET_10,
62     DISAS_TARGET_11,
63 } DisasJumpType;
64 
65 /**
66  * DisasContextBase:
67  * @tb: Translation block for this disassembly.
68  * @pc_first: Address of first guest instruction in this TB.
69  * @pc_next: Address of next guest instruction in this TB (current during
70  *           disassembly).
71  * @is_jmp: What instruction to disassemble next.
72  * @num_insns: Number of translated instructions (including current).
73  * @max_insns: Maximum number of instructions to be translated in this TB.
74  * @plugin_enabled: TCG plugin enabled in this TB.
75  * @fake_insn: True if translator_fake_ldb used.
76  * @insn_start: The last op emitted by the insn_start hook,
77  *              which is expected to be INDEX_op_insn_start.
78  *
79  * Architecture-agnostic disassembly context.
80  */
81 struct DisasContextBase {
82     TranslationBlock *tb;
83     vaddr pc_first;
84     vaddr pc_next;
85     DisasJumpType is_jmp;
86     int num_insns;
87     int max_insns;
88     bool plugin_enabled;
89     bool fake_insn;
90     struct TCGOp *insn_start;
91     void *host_addr[2];
92 
93     /*
94      * Record insn data that we cannot read directly from host memory.
95      * There are only two reasons we cannot use host memory:
96      * (1) We are executing from I/O,
97      * (2) We are executing a synthetic instruction (s390x EX).
98      * In both cases we need record exactly one instruction,
99      * and thus the maximum amount of data we record is limited.
100      */
101     int record_start;
102     int record_len;
103     uint8_t record[32];
104 };
105 
106 /**
107  * TranslatorOps:
108  * @init_disas_context:
109  *      Initialize the target-specific portions of DisasContext struct.
110  *      The generic DisasContextBase has already been initialized.
111  *
112  * @tb_start:
113  *      Emit any code required before the start of the main loop,
114  *      after the generic gen_tb_start().
115  *
116  * @insn_start:
117  *      Emit the tcg_gen_insn_start opcode.
118  *
119  * @translate_insn:
120  *      Disassemble one instruction and set db->pc_next for the start
121  *      of the following instruction.  Set db->is_jmp as necessary to
122  *      terminate the main loop.
123  *
124  * @tb_stop:
125  *      Emit any opcodes required to exit the TB, based on db->is_jmp.
126  *
127  * @disas_log:
128  *      Print instruction disassembly to log.
129  */
130 typedef struct TranslatorOps {
131     void (*init_disas_context)(DisasContextBase *db, CPUState *cpu);
132     void (*tb_start)(DisasContextBase *db, CPUState *cpu);
133     void (*insn_start)(DisasContextBase *db, CPUState *cpu);
134     void (*translate_insn)(DisasContextBase *db, CPUState *cpu);
135     void (*tb_stop)(DisasContextBase *db, CPUState *cpu);
136     bool (*disas_log)(const DisasContextBase *db, CPUState *cpu, FILE *f);
137 } TranslatorOps;
138 
139 /**
140  * translator_loop:
141  * @cpu: Target vCPU.
142  * @tb: Translation block.
143  * @max_insns: Maximum number of insns to translate.
144  * @pc: guest virtual program counter address
145  * @host_pc: host physical program counter address
146  * @ops: Target-specific operations.
147  * @db: Disassembly context.
148  *
149  * Generic translator loop.
150  *
151  * Translation will stop in the following cases (in order):
152  * - When is_jmp set by #TranslatorOps::breakpoint_check.
153  *   - set to DISAS_TOO_MANY exits after translating one more insn
154  *   - set to any other value than DISAS_NEXT exits immediately.
155  * - When is_jmp set by #TranslatorOps::translate_insn.
156  *   - set to any value other than DISAS_NEXT exits immediately.
157  * - When the TCG operation buffer is full.
158  * - When single-stepping is enabled (system-wide or on the current vCPU).
159  * - When too many instructions have been translated.
160  */
161 void translator_loop(CPUState *cpu, TranslationBlock *tb, int *max_insns,
162                      vaddr pc, void *host_pc, const TranslatorOps *ops,
163                      DisasContextBase *db);
164 
165 /**
166  * translator_use_goto_tb
167  * @db: Disassembly context
168  * @dest: target pc of the goto
169  *
170  * Return true if goto_tb is allowed between the current TB
171  * and the destination PC.
172  */
173 bool translator_use_goto_tb(DisasContextBase *db, vaddr dest);
174 
175 /**
176  * translator_io_start
177  * @db: Disassembly context
178  *
179  * If icount is enabled, set cpu->can_do_io, adjust db->is_jmp to
180  * DISAS_TOO_MANY if it is still DISAS_NEXT, and return true.
181  * Otherwise return false.
182  */
183 bool translator_io_start(DisasContextBase *db);
184 
185 /*
186  * Translator Load Functions
187  *
188  * These are intended to replace the direct usage of the cpu_ld*_code
189  * functions and are mandatory for front-ends that have been migrated
190  * to the common translator_loop. These functions are only intended
191  * to be called from the translation stage and should not be called
192  * from helper functions. Those functions should be converted to encode
193  * the relevant information at translation time.
194  */
195 
196 uint8_t translator_ldub(CPUArchState *env, DisasContextBase *db, vaddr pc);
197 uint16_t translator_lduw(CPUArchState *env, DisasContextBase *db, vaddr pc);
198 uint32_t translator_ldl(CPUArchState *env, DisasContextBase *db, vaddr pc);
199 uint64_t translator_ldq(CPUArchState *env, DisasContextBase *db, vaddr pc);
200 
201 static inline uint16_t
202 translator_lduw_swap(CPUArchState *env, DisasContextBase *db,
203                      vaddr pc, bool do_swap)
204 {
205     uint16_t ret = translator_lduw(env, db, pc);
206     if (do_swap) {
207         ret = bswap16(ret);
208     }
209     return ret;
210 }
211 
212 static inline uint32_t
213 translator_ldl_swap(CPUArchState *env, DisasContextBase *db,
214                     vaddr pc, bool do_swap)
215 {
216     uint32_t ret = translator_ldl(env, db, pc);
217     if (do_swap) {
218         ret = bswap32(ret);
219     }
220     return ret;
221 }
222 
223 static inline uint64_t
224 translator_ldq_swap(CPUArchState *env, DisasContextBase *db,
225                     vaddr pc, bool do_swap)
226 {
227     uint64_t ret = translator_ldq(env, db, pc);
228     if (do_swap) {
229         ret = bswap64(ret);
230     }
231     return ret;
232 }
233 
234 /**
235  * translator_fake_ld - fake instruction load
236  * @db: Disassembly context
237  * @data: bytes of instruction
238  * @len: number of bytes
239  *
240  * This is a special case helper used where the instruction we are
241  * about to translate comes from somewhere else (e.g. being
242  * re-synthesised for s390x "ex"). It ensures we update other areas of
243  * the translator with details of the executed instruction.
244  */
245 void translator_fake_ld(DisasContextBase *db, const void *data, size_t len);
246 
247 /**
248  * translator_st
249  * @db: disassembly context
250  * @dest: address to copy into
251  * @addr: virtual address within TB
252  * @len: length
253  *
254  * Copy @len bytes from @addr into @dest.
255  * All bytes must have been read during translation.
256  * Return true on success or false on failure.
257  */
258 bool translator_st(const DisasContextBase *db, void *dest,
259                    vaddr addr, size_t len);
260 
261 /**
262  * translator_st_len
263  * @db: disassembly context
264  *
265  * Return the number of bytes available to copy from the
266  * current translation block with translator_st.
267  */
268 size_t translator_st_len(const DisasContextBase *db);
269 
270 #ifdef COMPILING_PER_TARGET
271 /*
272  * Return whether addr is on the same page as where disassembly started.
273  * Translators can use this to enforce the rule that only single-insn
274  * translation blocks are allowed to cross page boundaries.
275  */
276 static inline bool is_same_page(const DisasContextBase *db, vaddr addr)
277 {
278     return ((addr ^ db->pc_first) & TARGET_PAGE_MASK) == 0;
279 }
280 #endif
281 
282 #endif /* EXEC__TRANSLATOR_H */
283