qemu/include/exec/translator.h
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   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 */
  39typedef 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 */
  70typedef 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 */
 115typedef 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);
 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 */
 144void translator_loop(const TranslatorOps *ops, DisasContextBase *db,
 145                     CPUState *cpu, TranslationBlock *tb, int max_insns);
 146
 147void 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 */
 157bool 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
 186FOR_EACH_TRANSLATOR_LD(GEN_TRANSLATOR_LD)
 187
 188#undef GEN_TRANSLATOR_LD
 189
 190#endif  /* EXEC__TRANSLATOR_H */
 191
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