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emulated atomic64: disable interrupts as the lock mechanism on !SMP

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Reviewed by:	jhibbits, bdragon
Differential Revision:	https://reviews.freebsd.org/D23015
This commit is contained in:
Kyle Evans 2020-01-03 18:29:20 +00:00
parent 770379b92c
commit 3a22f09cbf
1 changed files with 12 additions and 2 deletions
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14
sys/kern/subr_atomic64.c
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@ -55,9 +55,12 @@ enum {
};
#ifdef _KERNEL
#ifdef SMP
#define A64_POOL_SIZE MAXCPU
/* Estimated size of a cacheline */
#define CACHE_ALIGN CACHE_LINE_SIZE
static struct mtx a64_mtx_pool[A64_POOL_SIZE];
#define GET_MUTEX(p) \
(&a64_mtx_pool[(pmap_kextract((vm_offset_t)p) / CACHE_ALIGN) % (A64_POOL_SIZE)])
@ -68,6 +71,13 @@ enum {
#define UNLOCK_A64() if (smp_started) mtx_unlock(_amtx)
#else /* !SMP */
#define LOCK_A64() { register_t s = intr_disable()
#define UNLOCK_A64() intr_restore(s); }
#endif /* SMP */
#define ATOMIC64_EMU_UN(op, rt, block, ret) \
rt \
atomic_##op##_64(volatile u_int64_t *p) { \
@ -86,8 +96,6 @@ enum {
UNLOCK_A64(); \
ret; } struct hack
static struct mtx a64_mtx_pool[A64_POOL_SIZE];
ATOMIC64_EMU_BIN(add, void, (*p = *p + v), return);
ATOMIC64_EMU_BIN(clear, void, *p &= ~v, return);
ATOMIC64_EMU_BIN(fetchadd, u_int64_t, (*p = *p + v, v = *p - v), return (v));
@ -126,6 +134,7 @@ int atomic_fcmpset_64(volatile u_int64_t *p, u_int64_t *old, u_int64_t new)
return (tmp == tmp_old);
}
#ifdef SMP
static void
atomic64_mtxinit(void *x __unused)
{
@ -136,5 +145,6 @@ atomic64_mtxinit(void *x __unused)
}
SYSINIT(atomic64_mtxinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, atomic64_mtxinit, NULL);
#endif /* SMP */
#endif /* _KERNEL */