accel/tcg/translator.c

   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 #include "qemu/osdep.h"
  11 #include "qemu/error-report.h"
  12 #include "tcg/tcg.h"
  13 #include "tcg/tcg-op.h"
  14 #include "exec/exec-all.h"
  15 #include "exec/gen-icount.h"
  16 #include "exec/log.h"
  17 #include "exec/translator.h"
  18 #include "exec/plugin-gen.h"
  19 #include "sysemu/replay.h"
  20
  21 /* Pairs with tcg_clear_temp_count.
  22    To be called by #TranslatorOps.{translate_insn,tb_stop} if
  23    (1) the target is sufficiently clean to support reporting,
  24    (2) as and when all temporaries are known to be consumed.
  25    For most targets, (2) is at the end of translate_insn.  */
  26 void translator_loop_temp_check(DisasContextBase *db)
  27 {
  28     if (tcg_check_temp_count()) {
  29         qemu_log("warning: TCG temporary leaks before "
  30                  TARGET_FMT_lx "\n", db->pc_next);
  31     }
  32 }
  33
  34 bool translator_use_goto_tb(DisasContextBase *db, target_ulong dest)
  35 {
  36     /* Suppress goto_tb if requested. */
  37     if (tb_cflags(db->tb) & CF_NO_GOTO_TB) {
  38         return false;
  39     }
  40
  41     /* Check for the dest on the same page as the start of the TB.  */
  42     return ((db->pc_first ^ dest) & TARGET_PAGE_MASK) == 0;
  43 }
  44
  45 static inline void translator_page_protect(DisasContextBase *dcbase,
  46                                            target_ulong pc)
  47 {
  48 #ifdef CONFIG_USER_ONLY
  49     dcbase->page_protect_end = pc | ~TARGET_PAGE_MASK;
  50     page_protect(pc);
  51 #endif
  52 }
  53
  54 void translator_loop(const TranslatorOps *ops, DisasContextBase *db,
  55                      CPUState *cpu, TranslationBlock *tb, int max_insns)
  56 {
  57     uint32_t cflags = tb_cflags(tb);
  58     bool plugin_enabled;
  59
  60     /* Initialize DisasContext */
  61     db->tb = tb;
  62     db->pc_first = tb->pc;
  63     db->pc_next = db->pc_first;
  64     db->is_jmp = DISAS_NEXT;
  65     db->num_insns = 0;
  66     db->max_insns = max_insns;
  67     db->singlestep_enabled = cflags & CF_SINGLE_STEP;
  68     translator_page_protect(db, db->pc_next);
  69
  70     ops->init_disas_context(db, cpu);
  71     tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
  72
  73     /* Reset the temp count so that we can identify leaks */
  74     tcg_clear_temp_count();
  75
  76     /* Start translating.  */
  77     gen_tb_start(db->tb);
  78     ops->tb_start(db, cpu);
  79     tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
  80
  81     plugin_enabled = plugin_gen_tb_start(cpu, tb, cflags & CF_MEMI_ONLY);
  82
  83     while (true) {
  84         db->num_insns++;
  85         ops->insn_start(db, cpu);
  86         tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
  87
  88         if (plugin_enabled) {
  89             plugin_gen_insn_start(cpu, db);
  90         }
  91
  92         /* Disassemble one instruction.  The translate_insn hook should
  93            update db->pc_next and db->is_jmp to indicate what should be
  94            done next -- either exiting this loop or locate the start of
  95            the next instruction.  */
  96         if (db->num_insns == db->max_insns && (cflags & CF_LAST_IO)) {
  97             /* Accept I/O on the last instruction.  */
  98             gen_io_start();
  99             ops->translate_insn(db, cpu);
 100         } else {
 101             /* we should only see CF_MEMI_ONLY for io_recompile */
 102             tcg_debug_assert(!(cflags & CF_MEMI_ONLY));
 103             ops->translate_insn(db, cpu);
 104         }
 105
 106         /* Stop translation if translate_insn so indicated.  */
 107         if (db->is_jmp != DISAS_NEXT) {
 108             break;
 109         }
 110
 111         /*
 112          * We can't instrument after instructions that change control
 113          * flow although this only really affects post-load operations.
 114          */
 115         if (plugin_enabled) {
 116             plugin_gen_insn_end();
 117         }
 118
 119         /* Stop translation if the output buffer is full,
 120            or we have executed all of the allowed instructions.  */
 121         if (tcg_op_buf_full() || db->num_insns >= db->max_insns) {
 122             db->is_jmp = DISAS_TOO_MANY;
 123             break;
 124         }
 125     }
 126
 127     /* Emit code to exit the TB, as indicated by db->is_jmp.  */
 128     ops->tb_stop(db, cpu);
 129     gen_tb_end(db->tb, db->num_insns);
 130
 131     if (plugin_enabled) {
 132         plugin_gen_tb_end(cpu);
 133     }
 134
 135     /* The disas_log hook may use these values rather than recompute.  */
 136     tb->size = db->pc_next - db->pc_first;
 137     tb->icount = db->num_insns;
 138
 139 #ifdef DEBUG_DISAS
 140     if (qemu_loglevel_mask(CPU_LOG_TB_IN_ASM)
 141         && qemu_log_in_addr_range(db->pc_first)) {
 142         FILE *logfile = qemu_log_lock();
 143         qemu_log("----------------\n");
 144         ops->disas_log(db, cpu);
 145         qemu_log("\n");
 146         qemu_log_unlock(logfile);
 147     }
 148 #endif
 149 }
 150
 151 static inline void translator_maybe_page_protect(DisasContextBase *dcbase,
 152                                                  target_ulong pc, size_t len)
 153 {
 154 #ifdef CONFIG_USER_ONLY
 155     target_ulong end = pc + len - 1;
 156
 157     if (end > dcbase->page_protect_end) {
 158         translator_page_protect(dcbase, end);
 159     }
 160 #endif
 161 }
 162
 163 #define GEN_TRANSLATOR_LD(fullname, type, load_fn, swap_fn)             \
 164     type fullname ## _swap(CPUArchState *env, DisasContextBase *dcbase, \
 165                            abi_ptr pc, bool do_swap)                    \
 166     {                                                                   \
 167         translator_maybe_page_protect(dcbase, pc, sizeof(type));        \
 168         type ret = load_fn(env, pc);                                    \
 169         if (do_swap) {                                                  \
 170             ret = swap_fn(ret);                                         \
 171         }                                                               \
 172         plugin_insn_append(pc, &ret, sizeof(ret));                      \
 173         return ret;                                                     \
 174     }
 175
 176 FOR_EACH_TRANSLATOR_LD(GEN_TRANSLATOR_LD)
 177
 178 #undef GEN_TRANSLATOR_LD