struct

#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"

struct
{
ulong locks;
ulong glare;
ulong inglare;
} lockstats;

static void
dumplockmem(char *tag, Lock *l)
{
uchar *cp;
int i;

iprint("%s: ", tag);
cp = (uchar*)l;
for(i = 0; i < 64; i++)
iprint("%2.2ux ", cp[i]);
iprint("\n");
}

void
lockloop(Lock *l, ulong pc)
{
Proc *p;

p = l->p;
print("lock 0x%lux loop key 0x%lux pc 0x%lux held by pc 0x%lux proc %lud\n",
l, l->key, pc, l->pc, p ? p->pid : 0);
dumpaproc(up);
if(p != nil)
dumpaproc(p);
}

int
lock(Lock *l)
{
int i;
ulong pc;

pc = getcallerpc(&l);

lockstats.locks++;
if(up)
up->nlocks++; /* prevent being scheded */
if(tas(&l->key) == 0){
if(up)
up->lastlock = l;
l->pc = pc;
l->p = up;
l->isilock = 0;
return 0;
}
if(up)
up->nlocks--; /* didn't get the lock, allow scheding */

lockstats.glare++;
for(;;){
lockstats.inglare++;
i = 0;
while(l->key){
if(i++ > 100000000){
i = 0;
lockloop(l, pc);
}
}
if(up)
up->nlocks++;
if(tas(&l->key) == 0){
if(up)
up->lastlock = l;
l->pc = pc;
l->p = up;
l->isilock = 0;
return 1;
}
if(up)
up->nlocks--;
}
return 0; /* For the compiler */
}

void
ilock(Lock *l)
{
ulong x;
ulong pc;

pc = getcallerpc(&l);
lockstats.locks++;

x = splhi();
if(tas(&l->key) == 0){
m->ilockdepth++;
if(up)
up->lastlock = l;
l->sr = x;
l->pc = pc;
l->p = up;
l->isilock = 1;
return;
}

lockstats.glare++;
if(conf.nmach < 2){
dumplockmem("ilock:", l);
panic("ilock: no way out: pc %luX\n", pc);
}

for(;;){
lockstats.inglare++;
splx(x);
while(l->key)
;
x = splhi();
if(tas(&l->key) == 0){
m->ilockdepth++;
if(up)
up->lastlock = l;
l->sr = x;
l->pc = pc;
l->p = up;
l->isilock = 1;
return;
}
}
}

int
canlock(Lock *l)
{
if(up)
up->nlocks++;
if(tas(&l->key)){
if(up)
up->nlocks--;
return 0;
}

if(up)
up->lastlock = l;
l->pc = getcallerpc(&l);
l->p = up;
l->isilock = 0;
return 1;
}

void
unlock(Lock *l)
{
if(l->key == 0)
print("unlock: not locked: pc %luX\n", getcallerpc(&l));
if(l->isilock)
print("unlock of ilock: pc %lux, held by %lux\n", getcallerpc(&l), l->pc);
if(l->p != up)
print("unlock: up changed: pc %lux, acquired at pc %lux, lock p 0x%p, unlock up 0x%p\n", getcallerpc(&l), l->pc, l->p, up);
l->key = 0;
coherence();

if(up)
--up->nlocks;
}

void
iunlock(Lock *l)
{
ulong sr;

if(l->key == 0)
print("iunlock: not locked: pc %luX\n", getcallerpc(&l));
if(!l->isilock)
print("iunlock of lock: pc %lux, held by %lux\n", getcallerpc(&l), l->pc);
if(islo())
print("iunlock while lo: pc %lux, held by %lux\n", getcallerpc(&l), l->pc);

sr = l->sr;
l->key = 0;
coherence();

m->splpc = getcallerpc(&l);
m->ilockdepth--;
splxpc(sr);
}