81 lines
1.5 KiB
C
81 lines
1.5 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
|
|
|
|
#define LOCKMAGIC 0x6673ffea
|
|
|
|
extern int use_console_lock;
|
|
|
|
void
|
|
initlock(struct spinlock *lock, char *name)
|
|
{
|
|
lock->magic = LOCKMAGIC;
|
|
lock->name = name;
|
|
lock->locked = 0;
|
|
lock->cpu = 0xffffffff;
|
|
}
|
|
|
|
void
|
|
getcallerpcs(void *v, uint pcs[])
|
|
{
|
|
uint *ebp = (uint*)v - 2;
|
|
int i;
|
|
for(i = 0; i < 10 && ebp && ebp != (uint*)0xffffffff; ebp = (uint*)*ebp, i++){
|
|
pcs[i] = *(ebp + 1);
|
|
}
|
|
for( ; i < 10; i++)
|
|
pcs[i] = 0;
|
|
}
|
|
|
|
void
|
|
acquire(struct spinlock * lock)
|
|
{
|
|
if(lock->magic != LOCKMAGIC)
|
|
panic("weird lock magic");
|
|
if(holding(lock))
|
|
panic("acquire");
|
|
|
|
if(cpus[cpu()].nlock == 0)
|
|
cli();
|
|
cpus[cpu()].nlock++;
|
|
|
|
while(cmpxchg(0, 1, &lock->locked) == 1)
|
|
;
|
|
cpuid(0, 0, 0, 0, 0); // memory barrier
|
|
getcallerpcs(&lock, lock->pcs);
|
|
lock->cpu = cpu() + 10;
|
|
cpus[cpu()].lastacquire = lock;
|
|
}
|
|
|
|
void
|
|
release(struct spinlock * lock)
|
|
{
|
|
if(lock->magic != LOCKMAGIC)
|
|
panic("weird lock magic");
|
|
|
|
if(!holding(lock))
|
|
panic("release");
|
|
|
|
cpus[cpu()].lastrelease = lock;
|
|
lock->pcs[0] = 0;
|
|
lock->cpu = 0xffffffff;
|
|
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() + 10;
|
|
}
|