include/exec/translator.h

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