b8b572e101
from include/asm-powerpc. This is the result of a mkdir arch/powerpc/include/asm git mv include/asm-powerpc/* arch/powerpc/include/asm Followed by a few documentation/comment fixups and a couple of places where <asm-powepc/...> was being used explicitly. Of the latter only one was outside the arch code and it is a driver only built for powerpc. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
295 lines
6.6 KiB
C
295 lines
6.6 KiB
C
#ifndef __ASM_SPINLOCK_H
|
|
#define __ASM_SPINLOCK_H
|
|
#ifdef __KERNEL__
|
|
|
|
/*
|
|
* Simple spin lock operations.
|
|
*
|
|
* Copyright (C) 2001-2004 Paul Mackerras <paulus@au.ibm.com>, IBM
|
|
* Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
|
|
* Copyright (C) 2002 Dave Engebretsen <engebret@us.ibm.com>, IBM
|
|
* Rework to support virtual processors
|
|
*
|
|
* Type of int is used as a full 64b word is not necessary.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*
|
|
* (the type definitions are in asm/spinlock_types.h)
|
|
*/
|
|
#include <linux/irqflags.h>
|
|
#ifdef CONFIG_PPC64
|
|
#include <asm/paca.h>
|
|
#include <asm/hvcall.h>
|
|
#include <asm/iseries/hv_call.h>
|
|
#endif
|
|
#include <asm/asm-compat.h>
|
|
#include <asm/synch.h>
|
|
|
|
#define __raw_spin_is_locked(x) ((x)->slock != 0)
|
|
|
|
#ifdef CONFIG_PPC64
|
|
/* use 0x800000yy when locked, where yy == CPU number */
|
|
#define LOCK_TOKEN (*(u32 *)(&get_paca()->lock_token))
|
|
#else
|
|
#define LOCK_TOKEN 1
|
|
#endif
|
|
|
|
#if defined(CONFIG_PPC64) && defined(CONFIG_SMP)
|
|
#define CLEAR_IO_SYNC (get_paca()->io_sync = 0)
|
|
#define SYNC_IO do { \
|
|
if (unlikely(get_paca()->io_sync)) { \
|
|
mb(); \
|
|
get_paca()->io_sync = 0; \
|
|
} \
|
|
} while (0)
|
|
#else
|
|
#define CLEAR_IO_SYNC
|
|
#define SYNC_IO
|
|
#endif
|
|
|
|
/*
|
|
* This returns the old value in the lock, so we succeeded
|
|
* in getting the lock if the return value is 0.
|
|
*/
|
|
static inline unsigned long __spin_trylock(raw_spinlock_t *lock)
|
|
{
|
|
unsigned long tmp, token;
|
|
|
|
token = LOCK_TOKEN;
|
|
__asm__ __volatile__(
|
|
"1: lwarx %0,0,%2\n\
|
|
cmpwi 0,%0,0\n\
|
|
bne- 2f\n\
|
|
stwcx. %1,0,%2\n\
|
|
bne- 1b\n\
|
|
isync\n\
|
|
2:" : "=&r" (tmp)
|
|
: "r" (token), "r" (&lock->slock)
|
|
: "cr0", "memory");
|
|
|
|
return tmp;
|
|
}
|
|
|
|
static inline int __raw_spin_trylock(raw_spinlock_t *lock)
|
|
{
|
|
CLEAR_IO_SYNC;
|
|
return __spin_trylock(lock) == 0;
|
|
}
|
|
|
|
/*
|
|
* On a system with shared processors (that is, where a physical
|
|
* processor is multiplexed between several virtual processors),
|
|
* there is no point spinning on a lock if the holder of the lock
|
|
* isn't currently scheduled on a physical processor. Instead
|
|
* we detect this situation and ask the hypervisor to give the
|
|
* rest of our timeslice to the lock holder.
|
|
*
|
|
* So that we can tell which virtual processor is holding a lock,
|
|
* we put 0x80000000 | smp_processor_id() in the lock when it is
|
|
* held. Conveniently, we have a word in the paca that holds this
|
|
* value.
|
|
*/
|
|
|
|
#if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES)
|
|
/* We only yield to the hypervisor if we are in shared processor mode */
|
|
#define SHARED_PROCESSOR (get_lppaca()->shared_proc)
|
|
extern void __spin_yield(raw_spinlock_t *lock);
|
|
extern void __rw_yield(raw_rwlock_t *lock);
|
|
#else /* SPLPAR || ISERIES */
|
|
#define __spin_yield(x) barrier()
|
|
#define __rw_yield(x) barrier()
|
|
#define SHARED_PROCESSOR 0
|
|
#endif
|
|
|
|
static inline void __raw_spin_lock(raw_spinlock_t *lock)
|
|
{
|
|
CLEAR_IO_SYNC;
|
|
while (1) {
|
|
if (likely(__spin_trylock(lock) == 0))
|
|
break;
|
|
do {
|
|
HMT_low();
|
|
if (SHARED_PROCESSOR)
|
|
__spin_yield(lock);
|
|
} while (unlikely(lock->slock != 0));
|
|
HMT_medium();
|
|
}
|
|
}
|
|
|
|
static inline
|
|
void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags)
|
|
{
|
|
unsigned long flags_dis;
|
|
|
|
CLEAR_IO_SYNC;
|
|
while (1) {
|
|
if (likely(__spin_trylock(lock) == 0))
|
|
break;
|
|
local_save_flags(flags_dis);
|
|
local_irq_restore(flags);
|
|
do {
|
|
HMT_low();
|
|
if (SHARED_PROCESSOR)
|
|
__spin_yield(lock);
|
|
} while (unlikely(lock->slock != 0));
|
|
HMT_medium();
|
|
local_irq_restore(flags_dis);
|
|
}
|
|
}
|
|
|
|
static inline void __raw_spin_unlock(raw_spinlock_t *lock)
|
|
{
|
|
SYNC_IO;
|
|
__asm__ __volatile__("# __raw_spin_unlock\n\t"
|
|
LWSYNC_ON_SMP: : :"memory");
|
|
lock->slock = 0;
|
|
}
|
|
|
|
#ifdef CONFIG_PPC64
|
|
extern void __raw_spin_unlock_wait(raw_spinlock_t *lock);
|
|
#else
|
|
#define __raw_spin_unlock_wait(lock) \
|
|
do { while (__raw_spin_is_locked(lock)) cpu_relax(); } while (0)
|
|
#endif
|
|
|
|
/*
|
|
* Read-write spinlocks, allowing multiple readers
|
|
* but only one writer.
|
|
*
|
|
* NOTE! it is quite common to have readers in interrupts
|
|
* but no interrupt writers. For those circumstances we
|
|
* can "mix" irq-safe locks - any writer needs to get a
|
|
* irq-safe write-lock, but readers can get non-irqsafe
|
|
* read-locks.
|
|
*/
|
|
|
|
#define __raw_read_can_lock(rw) ((rw)->lock >= 0)
|
|
#define __raw_write_can_lock(rw) (!(rw)->lock)
|
|
|
|
#ifdef CONFIG_PPC64
|
|
#define __DO_SIGN_EXTEND "extsw %0,%0\n"
|
|
#define WRLOCK_TOKEN LOCK_TOKEN /* it's negative */
|
|
#else
|
|
#define __DO_SIGN_EXTEND
|
|
#define WRLOCK_TOKEN (-1)
|
|
#endif
|
|
|
|
/*
|
|
* This returns the old value in the lock + 1,
|
|
* so we got a read lock if the return value is > 0.
|
|
*/
|
|
static inline long __read_trylock(raw_rwlock_t *rw)
|
|
{
|
|
long tmp;
|
|
|
|
__asm__ __volatile__(
|
|
"1: lwarx %0,0,%1\n"
|
|
__DO_SIGN_EXTEND
|
|
" addic. %0,%0,1\n\
|
|
ble- 2f\n"
|
|
PPC405_ERR77(0,%1)
|
|
" stwcx. %0,0,%1\n\
|
|
bne- 1b\n\
|
|
isync\n\
|
|
2:" : "=&r" (tmp)
|
|
: "r" (&rw->lock)
|
|
: "cr0", "xer", "memory");
|
|
|
|
return tmp;
|
|
}
|
|
|
|
/*
|
|
* This returns the old value in the lock,
|
|
* so we got the write lock if the return value is 0.
|
|
*/
|
|
static inline long __write_trylock(raw_rwlock_t *rw)
|
|
{
|
|
long tmp, token;
|
|
|
|
token = WRLOCK_TOKEN;
|
|
__asm__ __volatile__(
|
|
"1: lwarx %0,0,%2\n\
|
|
cmpwi 0,%0,0\n\
|
|
bne- 2f\n"
|
|
PPC405_ERR77(0,%1)
|
|
" stwcx. %1,0,%2\n\
|
|
bne- 1b\n\
|
|
isync\n\
|
|
2:" : "=&r" (tmp)
|
|
: "r" (token), "r" (&rw->lock)
|
|
: "cr0", "memory");
|
|
|
|
return tmp;
|
|
}
|
|
|
|
static inline void __raw_read_lock(raw_rwlock_t *rw)
|
|
{
|
|
while (1) {
|
|
if (likely(__read_trylock(rw) > 0))
|
|
break;
|
|
do {
|
|
HMT_low();
|
|
if (SHARED_PROCESSOR)
|
|
__rw_yield(rw);
|
|
} while (unlikely(rw->lock < 0));
|
|
HMT_medium();
|
|
}
|
|
}
|
|
|
|
static inline void __raw_write_lock(raw_rwlock_t *rw)
|
|
{
|
|
while (1) {
|
|
if (likely(__write_trylock(rw) == 0))
|
|
break;
|
|
do {
|
|
HMT_low();
|
|
if (SHARED_PROCESSOR)
|
|
__rw_yield(rw);
|
|
} while (unlikely(rw->lock != 0));
|
|
HMT_medium();
|
|
}
|
|
}
|
|
|
|
static inline int __raw_read_trylock(raw_rwlock_t *rw)
|
|
{
|
|
return __read_trylock(rw) > 0;
|
|
}
|
|
|
|
static inline int __raw_write_trylock(raw_rwlock_t *rw)
|
|
{
|
|
return __write_trylock(rw) == 0;
|
|
}
|
|
|
|
static inline void __raw_read_unlock(raw_rwlock_t *rw)
|
|
{
|
|
long tmp;
|
|
|
|
__asm__ __volatile__(
|
|
"# read_unlock\n\t"
|
|
LWSYNC_ON_SMP
|
|
"1: lwarx %0,0,%1\n\
|
|
addic %0,%0,-1\n"
|
|
PPC405_ERR77(0,%1)
|
|
" stwcx. %0,0,%1\n\
|
|
bne- 1b"
|
|
: "=&r"(tmp)
|
|
: "r"(&rw->lock)
|
|
: "cr0", "memory");
|
|
}
|
|
|
|
static inline void __raw_write_unlock(raw_rwlock_t *rw)
|
|
{
|
|
__asm__ __volatile__("# write_unlock\n\t"
|
|
LWSYNC_ON_SMP: : :"memory");
|
|
rw->lock = 0;
|
|
}
|
|
|
|
#define _raw_spin_relax(lock) __spin_yield(lock)
|
|
#define _raw_read_relax(lock) __rw_yield(lock)
|
|
#define _raw_write_relax(lock) __rw_yield(lock)
|
|
|
|
#endif /* __KERNEL__ */
|
|
#endif /* __ASM_SPINLOCK_H */
|