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tcg: Merge tb_find_slow() and tb_find_fast() 

These functions are not too big and can be merged together. This makes
locking scheme more clear and easier to follow.

Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com>
Signed-off-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20160715175852.30749-12-sergey.fedorov@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sergey Fedorov 2016-07-15 20:58:51 +03:00 committed by Paolo Bonzini
parent 74d356dd48
commit bd2710d5da
1 changed files with 30 additions and 42 deletions
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72
cpu-exec.c
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@ -279,45 +279,9 @@ static TranslationBlock *tb_find_physical(CPUState *cpu,
return qht_lookup(&tcg_ctx.tb_ctx.htable, tb_cmp, &desc, h);
}
static TranslationBlock *tb_find_slow(CPUState *cpu,
target_ulong pc,
target_ulong cs_base,
uint32_t flags,
bool *have_tb_lock)
{
TranslationBlock *tb;
tb = tb_find_physical(cpu, pc, cs_base, flags);
if (!tb) {
/* 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();
*have_tb_lock = true;
/* 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);
}
mmap_unlock();
}
/* 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;
}
static inline TranslationBlock *tb_find_fast(CPUState *cpu,
TranslationBlock *last_tb,
int tb_exit)
static inline TranslationBlock *tb_find(CPUState *cpu,
TranslationBlock *last_tb,
int tb_exit)
{
CPUArchState *env = (CPUArchState *)cpu->env_ptr;
TranslationBlock *tb;
@ -332,7 +296,31 @@ static inline TranslationBlock *tb_find_fast(CPUState *cpu,
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)) {
tb = tb_find_slow(cpu, pc, cs_base, flags, &have_tb_lock);
tb = tb_find_physical(cpu, pc, cs_base, flags);
if (!tb) {
/* 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();
have_tb_lock = true;
/* 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);
}
mmap_unlock();
}
/* 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);
}
#ifndef CONFIG_USER_ONLY
/* We don't take care of direct jumps when address mapping changes in
@ -437,7 +425,7 @@ static inline bool cpu_handle_exception(CPUState *cpu, int *ret)
} else if (replay_has_exception()
&& cpu->icount_decr.u16.low + cpu->icount_extra == 0) {
/* try to cause an exception pending in the log */
cpu_exec_nocache(cpu, 1, tb_find_fast(cpu, NULL, 0), true);
cpu_exec_nocache(cpu, 1, tb_find(cpu, NULL, 0), true);
*ret = -1;
return true;
#endif
@ -620,7 +608,7 @@ int cpu_exec(CPUState *cpu)
atomic_mb_set(&cpu->tb_flushed, false); /* reset before first TB lookup */
for(;;) {
cpu_handle_interrupt(cpu, &last_tb);
tb = tb_find_fast(cpu, last_tb, tb_exit);
tb = tb_find(cpu, last_tb, tb_exit);
cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit, &sc);
/* Try to align the host and virtual clocks
if the guest is in advance */