49 lines
1.1 KiB
C
49 lines
1.1 KiB
C
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#ifndef JOS_INC_SPINLOCK_H
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#define JOS_INC_SPINLOCK_H
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#include <inc/types.h>
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// Comment this to disable spinlock debugging
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#define DEBUG_SPINLOCK
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// Mutual exclusion lock.
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struct spinlock {
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unsigned locked; // Is the lock held?
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#ifdef DEBUG_SPINLOCK
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// For debugging:
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char *name; // Name of lock.
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struct CpuInfo *cpu; // The CPU holding the lock.
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uintptr_t pcs[10]; // The call stack (an array of program counters)
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// that locked the lock.
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#endif
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};
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void __spin_initlock(struct spinlock *lk, char *name);
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void spin_lock(struct spinlock *lk);
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void spin_unlock(struct spinlock *lk);
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#define spin_initlock(lock) __spin_initlock(lock, #lock)
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extern struct spinlock kernel_lock;
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static inline void
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lock_kernel(void)
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{
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spin_lock(&kernel_lock);
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}
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static inline void
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unlock_kernel(void)
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{
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spin_unlock(&kernel_lock);
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// Normally we wouldn't need to do this, but QEMU only runs
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// one CPU at a time and has a long time-slice. Without the
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// pause, this CPU is likely to reacquire the lock before
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// another CPU has even been given a chance to acquire it.
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asm volatile("pause");
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}
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#endif
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