2005-04-17 06:20:36 +08:00
|
|
|
/*
|
|
|
|
* Locks for smp ppc
|
|
|
|
*
|
|
|
|
* Written by Cort Dougan (cort@cs.nmt.edu)
|
|
|
|
*/
|
|
|
|
|
|
|
|
#include <linux/config.h>
|
|
|
|
#include <linux/sched.h>
|
|
|
|
#include <linux/spinlock.h>
|
|
|
|
#include <linux/module.h>
|
|
|
|
#include <asm/ppc_asm.h>
|
|
|
|
#include <asm/smp.h>
|
|
|
|
|
|
|
|
#ifdef CONFIG_DEBUG_SPINLOCK
|
|
|
|
|
|
|
|
#undef INIT_STUCK
|
|
|
|
#define INIT_STUCK 200000000 /*0xffffffff*/
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Try to acquire a spinlock.
|
|
|
|
* Only does the stwcx. if the load returned 0 - the Programming
|
|
|
|
* Environments Manual suggests not doing unnecessary stcwx.'s
|
|
|
|
* since they may inhibit forward progress by other CPUs in getting
|
|
|
|
* a lock.
|
|
|
|
*/
|
|
|
|
static inline unsigned long __spin_trylock(volatile unsigned long *lock)
|
|
|
|
{
|
|
|
|
unsigned long ret;
|
|
|
|
|
|
|
|
__asm__ __volatile__ ("\n\
|
|
|
|
1: lwarx %0,0,%1\n\
|
|
|
|
cmpwi 0,%0,0\n\
|
|
|
|
bne 2f\n"
|
|
|
|
PPC405_ERR77(0,%1)
|
|
|
|
" stwcx. %2,0,%1\n\
|
|
|
|
bne- 1b\n\
|
|
|
|
isync\n\
|
|
|
|
2:"
|
|
|
|
: "=&r"(ret)
|
|
|
|
: "r"(lock), "r"(1)
|
|
|
|
: "cr0", "memory");
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
void _raw_spin_lock(spinlock_t *lock)
|
|
|
|
{
|
|
|
|
int cpu = smp_processor_id();
|
|
|
|
unsigned int stuck = INIT_STUCK;
|
|
|
|
while (__spin_trylock(&lock->lock)) {
|
|
|
|
while ((unsigned volatile long)lock->lock != 0) {
|
|
|
|
if (!--stuck) {
|
|
|
|
printk("_spin_lock(%p) CPU#%d NIP %p"
|
|
|
|
" holder: cpu %ld pc %08lX\n",
|
|
|
|
lock, cpu, __builtin_return_address(0),
|
|
|
|
lock->owner_cpu,lock->owner_pc);
|
|
|
|
stuck = INIT_STUCK;
|
|
|
|
/* steal the lock */
|
|
|
|
/*xchg_u32((void *)&lock->lock,0);*/
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
lock->owner_pc = (unsigned long)__builtin_return_address(0);
|
|
|
|
lock->owner_cpu = cpu;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(_raw_spin_lock);
|
|
|
|
|
|
|
|
int _raw_spin_trylock(spinlock_t *lock)
|
|
|
|
{
|
|
|
|
if (__spin_trylock(&lock->lock))
|
|
|
|
return 0;
|
|
|
|
lock->owner_cpu = smp_processor_id();
|
|
|
|
lock->owner_pc = (unsigned long)__builtin_return_address(0);
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(_raw_spin_trylock);
|
|
|
|
|
|
|
|
void _raw_spin_unlock(spinlock_t *lp)
|
|
|
|
{
|
|
|
|
if ( !lp->lock )
|
|
|
|
printk("_spin_unlock(%p): no lock cpu %d curr PC %p %s/%d\n",
|
|
|
|
lp, smp_processor_id(), __builtin_return_address(0),
|
|
|
|
current->comm, current->pid);
|
|
|
|
if ( lp->owner_cpu != smp_processor_id() )
|
|
|
|
printk("_spin_unlock(%p): cpu %d trying clear of cpu %d pc %lx val %lx\n",
|
|
|
|
lp, smp_processor_id(), (int)lp->owner_cpu,
|
|
|
|
lp->owner_pc,lp->lock);
|
|
|
|
lp->owner_pc = lp->owner_cpu = 0;
|
|
|
|
wmb();
|
|
|
|
lp->lock = 0;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(_raw_spin_unlock);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* For rwlocks, zero is unlocked, -1 is write-locked,
|
|
|
|
* positive is read-locked.
|
|
|
|
*/
|
|
|
|
static __inline__ int __read_trylock(rwlock_t *rw)
|
|
|
|
{
|
|
|
|
signed int tmp;
|
|
|
|
|
|
|
|
__asm__ __volatile__(
|
|
|
|
"2: lwarx %0,0,%1 # __read_trylock\n\
|
|
|
|
addic. %0,%0,1\n\
|
|
|
|
ble- 1f\n"
|
|
|
|
PPC405_ERR77(0,%1)
|
|
|
|
" stwcx. %0,0,%1\n\
|
|
|
|
bne- 2b\n\
|
|
|
|
isync\n\
|
|
|
|
1:"
|
|
|
|
: "=&r"(tmp)
|
|
|
|
: "r"(&rw->lock)
|
|
|
|
: "cr0", "memory");
|
|
|
|
|
|
|
|
return tmp;
|
|
|
|
}
|
|
|
|
|
|
|
|
int _raw_read_trylock(rwlock_t *rw)
|
|
|
|
{
|
|
|
|
return __read_trylock(rw) > 0;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(_raw_read_trylock);
|
|
|
|
|
|
|
|
void _raw_read_lock(rwlock_t *rw)
|
|
|
|
{
|
|
|
|
unsigned int stuck;
|
|
|
|
|
|
|
|
while (__read_trylock(rw) <= 0) {
|
|
|
|
stuck = INIT_STUCK;
|
|
|
|
while (!read_can_lock(rw)) {
|
|
|
|
if (--stuck == 0) {
|
|
|
|
printk("_read_lock(%p) CPU#%d lock %d\n",
|
2005-06-22 08:14:34 +08:00
|
|
|
rw, raw_smp_processor_id(), rw->lock);
|
2005-04-17 06:20:36 +08:00
|
|
|
stuck = INIT_STUCK;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(_raw_read_lock);
|
|
|
|
|
|
|
|
void _raw_read_unlock(rwlock_t *rw)
|
|
|
|
{
|
|
|
|
if ( rw->lock == 0 )
|
|
|
|
printk("_read_unlock(): %s/%d (nip %08lX) lock %d\n",
|
|
|
|
current->comm,current->pid,current->thread.regs->nip,
|
|
|
|
rw->lock);
|
|
|
|
wmb();
|
|
|
|
atomic_dec((atomic_t *) &(rw)->lock);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(_raw_read_unlock);
|
|
|
|
|
|
|
|
void _raw_write_lock(rwlock_t *rw)
|
|
|
|
{
|
|
|
|
unsigned int stuck;
|
|
|
|
|
|
|
|
while (cmpxchg(&rw->lock, 0, -1) != 0) {
|
|
|
|
stuck = INIT_STUCK;
|
|
|
|
while (!write_can_lock(rw)) {
|
|
|
|
if (--stuck == 0) {
|
|
|
|
printk("write_lock(%p) CPU#%d lock %d)\n",
|
2005-06-22 08:14:34 +08:00
|
|
|
rw, raw_smp_processor_id(), rw->lock);
|
2005-04-17 06:20:36 +08:00
|
|
|
stuck = INIT_STUCK;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
wmb();
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(_raw_write_lock);
|
|
|
|
|
|
|
|
int _raw_write_trylock(rwlock_t *rw)
|
|
|
|
{
|
|
|
|
if (cmpxchg(&rw->lock, 0, -1) != 0)
|
|
|
|
return 0;
|
|
|
|
wmb();
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(_raw_write_trylock);
|
|
|
|
|
|
|
|
void _raw_write_unlock(rwlock_t *rw)
|
|
|
|
{
|
|
|
|
if (rw->lock >= 0)
|
|
|
|
printk("_write_lock(): %s/%d (nip %08lX) lock %d\n",
|
|
|
|
current->comm,current->pid,current->thread.regs->nip,
|
|
|
|
rw->lock);
|
|
|
|
wmb();
|
|
|
|
rw->lock = 0;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(_raw_write_unlock);
|
|
|
|
|
|
|
|
#endif
|