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 "exec/replay-core.h"
  20
  21 bool translator_use_goto_tb(DisasContextBase *db, target_ulong dest)
  22 {
  23     /* Suppress goto_tb if requested. */
  24     if (tb_cflags(db->tb) & CF_NO_GOTO_TB) {
  25         return false;
  26     }
  27
  28     /* Check for the dest on the same page as the start of the TB.  */
  29     return ((db->pc_first ^ dest) & TARGET_PAGE_MASK) == 0;
  30 }
  31
  32 void translator_loop(CPUState *cpu, TranslationBlock *tb, int *max_insns,
  33                      target_ulong pc, void *host_pc,
  34                      const TranslatorOps *ops, DisasContextBase *db)
  35 {
  36     uint32_t cflags = tb_cflags(tb);
  37     bool plugin_enabled;
  38
  39     /* Initialize DisasContext */
  40     db->tb = tb;
  41     db->pc_first = pc;
  42     db->pc_next = pc;
  43     db->is_jmp = DISAS_NEXT;
  44     db->num_insns = 0;
  45     db->max_insns = *max_insns;
  46     db->singlestep_enabled = cflags & CF_SINGLE_STEP;
  47     db->host_addr[0] = host_pc;
  48     db->host_addr[1] = NULL;
  49
  50 #ifdef CONFIG_USER_ONLY
  51     page_protect(pc);
  52 #endif
  53
  54     ops->init_disas_context(db, cpu);
  55     tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
  56
  57     /* Start translating.  */
  58     gen_tb_start(db->tb);
  59     ops->tb_start(db, cpu);
  60     tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
  61
  62     plugin_enabled = plugin_gen_tb_start(cpu, db, cflags & CF_MEMI_ONLY);
  63
  64     while (true) {
  65         *max_insns = ++db->num_insns;
  66         ops->insn_start(db, cpu);
  67         tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
  68
  69         if (plugin_enabled) {
  70             plugin_gen_insn_start(cpu, db);
  71         }
  72
  73         /* Disassemble one instruction.  The translate_insn hook should
  74            update db->pc_next and db->is_jmp to indicate what should be
  75            done next -- either exiting this loop or locate the start of
  76            the next instruction.  */
  77         if (db->num_insns == db->max_insns && (cflags & CF_LAST_IO)) {
  78             /* Accept I/O on the last instruction.  */
  79             gen_io_start();
  80             ops->translate_insn(db, cpu);
  81         } else {
  82             /* we should only see CF_MEMI_ONLY for io_recompile */
  83             tcg_debug_assert(!(cflags & CF_MEMI_ONLY));
  84             ops->translate_insn(db, cpu);
  85         }
  86
  87         /*
  88          * We can't instrument after instructions that change control
  89          * flow although this only really affects post-load operations.
  90          *
  91          * Calling plugin_gen_insn_end() before we possibly stop translation
  92          * is important. Even if this ends up as dead code, plugin generation
  93          * needs to see a matching plugin_gen_insn_{start,end}() pair in order
  94          * to accurately track instrumented helpers that might access memory.
  95          */
  96         if (plugin_enabled) {
  97             plugin_gen_insn_end();
  98         }
  99
 100         /* Stop translation if translate_insn so indicated.  */
 101         if (db->is_jmp != DISAS_NEXT) {
 102             break;
 103         }
 104
 105         /* Stop translation if the output buffer is full,
 106            or we have executed all of the allowed instructions.  */
 107         if (tcg_op_buf_full() || db->num_insns >= db->max_insns) {
 108             db->is_jmp = DISAS_TOO_MANY;
 109             break;
 110         }
 111     }
 112
 113     /* Emit code to exit the TB, as indicated by db->is_jmp.  */
 114     ops->tb_stop(db, cpu);
 115     gen_tb_end(db->tb, db->num_insns);
 116
 117     if (plugin_enabled) {
 118         plugin_gen_tb_end(cpu);
 119     }
 120
 121     /* The disas_log hook may use these values rather than recompute.  */
 122     tb->size = db->pc_next - db->pc_first;
 123     tb->icount = db->num_insns;
 124
 125 #ifdef DEBUG_DISAS
 126     if (qemu_loglevel_mask(CPU_LOG_TB_IN_ASM)
 127         && qemu_log_in_addr_range(db->pc_first)) {
 128         FILE *logfile = qemu_log_trylock();
 129         if (logfile) {
 130             fprintf(logfile, "----------------\n");
 131             ops->disas_log(db, cpu, logfile);
 132             fprintf(logfile, "\n");
 133             qemu_log_unlock(logfile);
 134         }
 135     }
 136 #endif
 137 }
 138
 139 static void *translator_access(CPUArchState *env, DisasContextBase *db,
 140                                target_ulong pc, size_t len)
 141 {
 142     void *host;
 143     target_ulong base, end;
 144     TranslationBlock *tb;
 145
 146     tb = db->tb;
 147
 148     /* Use slow path if first page is MMIO. */
 149     if (unlikely(tb_page_addr0(tb) == -1)) {
 150         return NULL;
 151     }
 152
 153     end = pc + len - 1;
 154     if (likely(is_same_page(db, end))) {
 155         host = db->host_addr[0];
 156         base = db->pc_first;
 157     } else {
 158         host = db->host_addr[1];
 159         base = TARGET_PAGE_ALIGN(db->pc_first);
 160         if (host == NULL) {
 161             tb_page_addr_t phys_page =
 162                 get_page_addr_code_hostp(env, base, &db->host_addr[1]);
 163
 164             /*
 165              * If the second page is MMIO, treat as if the first page
 166              * was MMIO as well, so that we do not cache the TB.
 167              */
 168             if (unlikely(phys_page == -1)) {
 169                 tb_set_page_addr0(tb, -1);
 170                 return NULL;
 171             }
 172
 173             tb_set_page_addr1(tb, phys_page);
 174 #ifdef CONFIG_USER_ONLY
 175             page_protect(end);
 176 #endif
 177             host = db->host_addr[1];
 178         }
 179
 180         /* Use slow path when crossing pages. */
 181         if (is_same_page(db, pc)) {
 182             return NULL;
 183         }
 184     }
 185
 186     tcg_debug_assert(pc >= base);
 187     return host + (pc - base);
 188 }
 189
 190 uint8_t translator_ldub(CPUArchState *env, DisasContextBase *db, abi_ptr pc)
 191 {
 192     uint8_t ret;
 193     void *p = translator_access(env, db, pc, sizeof(ret));
 194
 195     if (p) {
 196         plugin_insn_append(pc, p, sizeof(ret));
 197         return ldub_p(p);
 198     }
 199     ret = cpu_ldub_code(env, pc);
 200     plugin_insn_append(pc, &ret, sizeof(ret));
 201     return ret;
 202 }
 203
 204 uint16_t translator_lduw(CPUArchState *env, DisasContextBase *db, abi_ptr pc)
 205 {
 206     uint16_t ret, plug;
 207     void *p = translator_access(env, db, pc, sizeof(ret));
 208
 209     if (p) {
 210         plugin_insn_append(pc, p, sizeof(ret));
 211         return lduw_p(p);
 212     }
 213     ret = cpu_lduw_code(env, pc);
 214     plug = tswap16(ret);
 215     plugin_insn_append(pc, &plug, sizeof(ret));
 216     return ret;
 217 }
 218
 219 uint32_t translator_ldl(CPUArchState *env, DisasContextBase *db, abi_ptr pc)
 220 {
 221     uint32_t ret, plug;
 222     void *p = translator_access(env, db, pc, sizeof(ret));
 223
 224     if (p) {
 225         plugin_insn_append(pc, p, sizeof(ret));
 226         return ldl_p(p);
 227     }
 228     ret = cpu_ldl_code(env, pc);
 229     plug = tswap32(ret);
 230     plugin_insn_append(pc, &plug, sizeof(ret));
 231     return ret;
 232 }
 233
 234 uint64_t translator_ldq(CPUArchState *env, DisasContextBase *db, abi_ptr pc)
 235 {
 236     uint64_t ret, plug;
 237     void *p = translator_access(env, db, pc, sizeof(ret));
 238
 239     if (p) {
 240         plugin_insn_append(pc, p, sizeof(ret));
 241         return ldq_p(p);
 242     }
 243     ret = cpu_ldq_code(env, pc);
 244     plug = tswap64(ret);
 245     plugin_insn_append(pc, &plug, sizeof(ret));
 246     return ret;
 247 }