58 lines
1 KiB
C
58 lines
1 KiB
C
#include "types.h"
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#include "defs.h"
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#include "x86.h"
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#include "mmu.h"
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#include "param.h"
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#include "proc.h"
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#include "spinlock.h"
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// Can't call cprintf from inside these routines,
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// because cprintf uses them itself.
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//#define cprintf dont_use_cprintf
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extern int use_console_lock;
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int
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getcallerpc(void *v)
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{
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return ((int*)v)[-1];
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}
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void
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acquire(struct spinlock * lock)
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{
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if(holding(lock)){
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extern use_console_lock;
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use_console_lock = 0;
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cprintf("lock %s pc %x\n", lock->name ? lock->name : "", lock->pc);
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panic("acquire");
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}
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if(cpus[cpu()].nlock++ == 0)
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cli();
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while(cmpxchg(0, 1, &lock->locked) == 1)
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;
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cpuid(0, 0, 0, 0, 0); // memory barrier
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lock->pc = getcallerpc(&lock);
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lock->cpu = cpu();
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cpus[cpu()].lastacquire = lock;
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}
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void
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release(struct spinlock * lock)
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{
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if(!holding(lock))
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panic("release");
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cpus[cpu()].lastrelease = lock;
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cpuid(0, 0, 0, 0, 0); // memory barrier
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lock->locked = 0;
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if(--cpus[cpu()].nlock == 0)
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sti();
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}
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int
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holding(struct spinlock *lock)
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{
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return lock->locked && lock->cpu == cpu();
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}
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