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