mirror of https://gitee.com/openkylin/qemu.git
84 lines
2.4 KiB
C
84 lines
2.4 KiB
C
|
/*
|
||
|
|
* Copyright (C) 2018, Emilio G. Cota <cota@braap.org>
|
||
|
|
*
|
||
|
|
* License: GNU GPL, version 2 or later.
|
||
|
|
* See the COPYING file in the top-level directory.
|
||
|
|
*/
|
||
|
|
#include "qemu/osdep.h"
|
||
|
|
#include "qemu/atomic.h"
|
||
|
|
#include "qemu/thread.h"
|
||
|
|
|
||
|
|
#ifdef CONFIG_ATOMIC64
|
||
|
|
#error This file must only be compiled if !CONFIG_ATOMIC64
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/*
|
||
|
|
* When !CONFIG_ATOMIC64, we serialize both reads and writes with spinlocks.
|
||
|
|
* We use an array of spinlocks, with padding computed at run-time based on
|
||
|
|
* the host's dcache line size.
|
||
|
|
* We point to the array with a void * to simplify the padding's computation.
|
||
|
|
* Each spinlock is located every lock_size bytes.
|
||
|
|
*/
|
||
|
|
static void *lock_array;
|
||
|
|
static size_t lock_size;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Systems without CONFIG_ATOMIC64 are unlikely to have many cores, so we use a
|
||
|
|
* small array of locks.
|
||
|
|
*/
|
||
|
|
#define NR_LOCKS 16
|
||
|
|
|
||
|
|
static QemuSpin *addr_to_lock(const void *addr)
|
||
|
|
{
|
||
|
|
uintptr_t a = (uintptr_t)addr;
|
||
|
|
uintptr_t idx;
|
||
|
|
|
||
|
|
idx = a >> qemu_dcache_linesize_log;
|
||
|
|
idx ^= (idx >> 8) ^ (idx >> 16);
|
||
|
|
idx &= NR_LOCKS - 1;
|
||
|
|
return lock_array + idx * lock_size;
|
||
|
|
}
|
||
|
|
|
||
|
|
#define GEN_READ(name, type) \
|
||
|
|
type name(const type *ptr) \
|
||
|
|
{ \
|
||
|
|
QemuSpin *lock = addr_to_lock(ptr); \
|
||
|
|
type ret; \
|
||
|
|
\
|
||
|
|
qemu_spin_lock(lock); \
|
||
|
|
ret = *ptr; \
|
||
|
|
qemu_spin_unlock(lock); \
|
||
|
|
return ret; \
|
||
|
|
}
|
||
|
|
|
||
|
|
GEN_READ(atomic_read_i64, int64_t)
|
||
|
|
GEN_READ(atomic_read_u64, uint64_t)
|
||
|
|
#undef GEN_READ
|
||
|
|
|
||
|
|
#define GEN_SET(name, type) \
|
||
|
|
void name(type *ptr, type val) \
|
||
|
|
{ \
|
||
|
|
QemuSpin *lock = addr_to_lock(ptr); \
|
||
|
|
\
|
||
|
|
qemu_spin_lock(lock); \
|
||
|
|
*ptr = val; \
|
||
|
|
qemu_spin_unlock(lock); \
|
||
|
|
}
|
||
|
|
|
||
|
|
GEN_SET(atomic_set_i64, int64_t)
|
||
|
|
GEN_SET(atomic_set_u64, uint64_t)
|
||
|
|
#undef GEN_SET
|
||
|
|
|
||
|
|
void atomic64_init(void)
|
||
|
|
{
|
||
|
|
int i;
|
||
|
|
|
||
|
|
lock_size = ROUND_UP(sizeof(QemuSpin), qemu_dcache_linesize);
|
||
|
|
lock_array = qemu_memalign(qemu_dcache_linesize, lock_size * NR_LOCKS);
|
||
|
|
for (i = 0; i < NR_LOCKS; i++) {
|
||
|
|
QemuSpin *lock = lock_array + i * lock_size;
|
||
|
|
|
||
|
|
qemu_spin_init(lock);
|
||
|
|
}
|
||
|
|
}
|