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/*
* <asm/smplock.h>
*
* i386 SMP lock implementation
*/
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/sched.h>
#include <asm/current.h>
extern spinlock_t kernel_flag;
#define kernel_locked() spin_is_locked(&kernel_flag)
/*
* Release global kernel lock and global interrupt lock
*/
#define release_kernel_lock(task, cpu) \
do { \
if (task->lock_depth >= 0) \
spin_unlock(&kernel_flag); \
release_irqlock(cpu); \
__sti(); \
} while (0)
/*
* Re-acquire the kernel lock
*/
#define reacquire_kernel_lock(task) \
do { \
if (task->lock_depth >= 0) \
spin_lock(&kernel_flag); \
} while (0)
/*
* Getting the big kernel lock.
*
* This cannot happen asynchronously,
* so we only need to worry about other
* CPU's.
*/
static __inline__ void lock_kernel(void)
{
#if 1
if (!++current->lock_depth)
spin_lock(&kernel_flag);
#else
__asm__ __volatile__(
"incl %1\n\t"
"jne 9f"
spin_lock_string
"\n9:"
:"=m" (__dummy_lock(&kernel_flag)),
"=m" (current->lock_depth));
#endif
}
static __inline__ void unlock_kernel(void)
{
if (current->lock_depth < 0)
BUG();
#if 1
if (--current->lock_depth < 0)
spin_unlock(&kernel_flag);
#else
__asm__ __volatile__(
"decl %1\n\t"
"jns 9f\n\t"
spin_unlock_string
"\n9:"
:"=m" (__dummy_lock(&kernel_flag)),
"=m" (current->lock_depth));
#endif
}
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