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-rw-r--r--cpu-exec.c48
1 files changed, 21 insertions, 27 deletions
diff --git a/cpu-exec.c b/cpu-exec.c
index cdaab1dbcd..7ca2b71a89 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -287,35 +287,29 @@ static TranslationBlock *tb_find_slow(CPUState *cpu,
TranslationBlock *tb;
tb = tb_find_physical(cpu, pc, cs_base, flags);
- if (tb) {
- goto found;
- }
+ if (!tb) {
-#ifdef CONFIG_USER_ONLY
- /* mmap_lock is needed by tb_gen_code, and mmap_lock must be
- * taken outside tb_lock. Since we're momentarily dropping
- * tb_lock, there's a chance that our desired tb has been
- * translated.
- */
- tb_unlock();
- mmap_lock();
- tb_lock();
- tb = tb_find_physical(cpu, pc, cs_base, flags);
- if (tb) {
- mmap_unlock();
- goto found;
- }
-#endif
+ /* mmap_lock is needed by tb_gen_code, and mmap_lock must be
+ * taken outside tb_lock. As system emulation is currently
+ * single threaded the locks are NOPs.
+ */
+ mmap_lock();
+ tb_lock();
- /* if no translated code available, then translate it now */
- tb = tb_gen_code(cpu, pc, cs_base, flags, 0);
+ /* There's a chance that our desired tb has been translated while
+ * taking the locks so we check again inside the lock.
+ */
+ tb = tb_find_physical(cpu, pc, cs_base, flags);
+ if (!tb) {
+ /* if no translated code available, then translate it now */
+ tb = tb_gen_code(cpu, pc, cs_base, flags, 0);
+ }
-#ifdef CONFIG_USER_ONLY
- mmap_unlock();
-#endif
+ tb_unlock();
+ mmap_unlock();
+ }
-found:
- /* we add the TB in the virtual pc hash table */
+ /* We add the TB in the virtual pc hash table for the fast lookup */
atomic_set(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)], tb);
return tb;
}
@@ -333,7 +327,6 @@ static inline TranslationBlock *tb_find_fast(CPUState *cpu,
always be the same before a given translated block
is executed. */
cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
- tb_lock();
tb = atomic_rcu_read(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)]);
if (unlikely(!tb || tb->pc != pc || tb->cs_base != cs_base ||
tb->flags != flags)) {
@@ -350,14 +343,15 @@ static inline TranslationBlock *tb_find_fast(CPUState *cpu,
#endif
/* See if we can patch the calling TB. */
if (last_tb && !qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) {
+ tb_lock();
/* Check if translation buffer has been flushed */
if (cpu->tb_flushed) {
cpu->tb_flushed = false;
} else if (!tb->invalid) {
tb_add_jump(last_tb, tb_exit, tb);
}
+ tb_unlock();
}
- tb_unlock();
return tb;
}