// SPDX-License-Identifier: GPL-2.0-or-later/* * Spin and read/write 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 */ #include <linux/kernel.h>#include <linux/spinlock.h>#include <linux/export.h>#include <linux/smp.h> /* waiting for a spinlock... */#if defined(CONFIG_PPC_SPLPAR)#include <asm/hvcall.h>#include <asm/smp.h> void splpar_spin_yield(arch_spinlock_t *lock){	unsigned int lock_value, holder_cpu, yield_count; 	lock_value = lock->slock;	if (lock_value == 0)		return;	holder_cpu = lock_value & 0xffff;	BUG_ON(holder_cpu >= NR_CPUS); 	yield_count = yield_count_of(holder_cpu);	if ((yield_count & 1) == 0)		return;		/* virtual cpu is currently running */	rmb();	if (lock->slock != lock_value)		return;		/* something has changed */	yield_to_preempted(holder_cpu, yield_count);}EXPORT_SYMBOL_GPL(splpar_spin_yield); /* * Waiting for a read lock or a write lock on a rwlock... * This turns out to be the same for read and write locks, since * we only know the holder if it is write-locked. */void splpar_rw_yield(arch_rwlock_t *rw){	int lock_value;	unsigned int holder_cpu, yield_count; 	lock_value = rw->lock;	if (lock_value >= 0)		return;		/* no write lock at present */	holder_cpu = lock_value & 0xffff;	BUG_ON(holder_cpu >= NR_CPUS); 	yield_count = yield_count_of(holder_cpu);	if ((yield_count & 1) == 0)		return;		/* virtual cpu is currently running */	rmb();	if (rw->lock != lock_value)		return;		/* something has changed */	yield_to_preempted(holder_cpu, yield_count);}#endif