spinlock.c | Explore in Territory

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (2004) Linus Torvalds
 *
 * Author: Zwane Mwaikambo <[email protected]>
 *
 * Copyright (2004, 2005) Ingo Molnar
 *
 * This file contains the spinlock/rwlock implementations for the
 * SMP and the DEBUG_SPINLOCK cases. (UP-nondebug inlines them)
 *
 * Note that some architectures have special knowledge about the
 * stack frames of these functions in their profile_pc. If you
 * change anything significant here that could change the stack
 * frame contact the architecture maintainers.
 */

#include <linux/linkage.h>
#include <linux/preempt.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/debug_locks.h>
#include <linux/export.h>

#ifdef CONFIG_MMIOWB
#ifndef arch_mmiowb_state
DEFINE_PER_CPU(struct mmiowb_state, __mmiowb_state);
EXPORT_PER_CPU_SYMBOL(__mmiowb_state);
#endif
#endif

/*
 * If lockdep is enabled then we use the non-preemption spin-ops
 * even on CONFIG_PREEMPT, because lockdep assumes that interrupts are
 * not re-enabled during lock-acquire (which the preempt-spin-ops do):
 */
#if !defined(CONFIG_GENERIC_LOCKBREAK) || defined(CONFIG_DEBUG_LOCK_ALLOC)
/*
 * The __lock_function inlines are taken from
 * spinlock : include/linux/spinlock_api_smp.h
 * rwlock   : include/linux/rwlock_api_smp.h
 */
#else

/*
 * Some architectures can relax in favour of the CPU owning the lock.
 */
#ifndef arch_read_relax
#define arch_read_relax …
#endif
#ifndef arch_write_relax
#define arch_write_relax …
#endif
#ifndef arch_spin_relax
#define arch_spin_relax …
#endif

/*
 * We build the __lock_function inlines here. They are too large for
 * inlining all over the place, but here is only one user per function
 * which embeds them into the calling _lock_function below.
 *
 * This could be a long-held lock. We both prepare to spin for a long
 * time (making _this_ CPU preemptible if possible), and we also signal
 * towards that other CPU that it should break the lock ASAP.
 */
#define BUILD_LOCK_OPS …									\

/*
 * Build preemption-friendly versions of the following
 * lock-spinning functions:
 *
 *         __[spin|read|write]_lock()
 *         __[spin|read|write]_lock_irq()
 *         __[spin|read|write]_lock_irqsave()
 *         __[spin|read|write]_lock_bh()
 */
BUILD_LOCK_OPS(spin, raw_spinlock);

#ifndef CONFIG_PREEMPT_RT
BUILD_LOCK_OPS(read, rwlock);
BUILD_LOCK_OPS(write, rwlock);
#endif

#endif

#ifndef CONFIG_INLINE_SPIN_TRYLOCK
noinline int __lockfunc _raw_spin_trylock(raw_spinlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_SPIN_TRYLOCK_BH
noinline int __lockfunc _raw_spin_trylock_bh(raw_spinlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_SPIN_LOCK
noinline void __lockfunc _raw_spin_lock(raw_spinlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_SPIN_LOCK_IRQSAVE
noinline unsigned long __lockfunc _raw_spin_lock_irqsave(raw_spinlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_SPIN_LOCK_IRQ
noinline void __lockfunc _raw_spin_lock_irq(raw_spinlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_SPIN_LOCK_BH
noinline void __lockfunc _raw_spin_lock_bh(raw_spinlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifdef CONFIG_UNINLINE_SPIN_UNLOCK
noinline void __lockfunc _raw_spin_unlock(raw_spinlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQRESTORE
noinline void __lockfunc _raw_spin_unlock_irqrestore(raw_spinlock_t *lock, unsigned long flags)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_SPIN_UNLOCK_IRQ
noinline void __lockfunc _raw_spin_unlock_irq(raw_spinlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_SPIN_UNLOCK_BH
noinline void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_PREEMPT_RT

#ifndef CONFIG_INLINE_READ_TRYLOCK
noinline int __lockfunc _raw_read_trylock(rwlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_READ_LOCK
noinline void __lockfunc _raw_read_lock(rwlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_READ_LOCK_IRQSAVE
noinline unsigned long __lockfunc _raw_read_lock_irqsave(rwlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_READ_LOCK_IRQ
noinline void __lockfunc _raw_read_lock_irq(rwlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_READ_LOCK_BH
noinline void __lockfunc _raw_read_lock_bh(rwlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_READ_UNLOCK
noinline void __lockfunc _raw_read_unlock(rwlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_READ_UNLOCK_IRQRESTORE
noinline void __lockfunc _raw_read_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_READ_UNLOCK_IRQ
noinline void __lockfunc _raw_read_unlock_irq(rwlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_READ_UNLOCK_BH
noinline void __lockfunc _raw_read_unlock_bh(rwlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_WRITE_TRYLOCK
noinline int __lockfunc _raw_write_trylock(rwlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_WRITE_LOCK
noinline void __lockfunc _raw_write_lock(rwlock_t *lock)
{ … }
EXPORT_SYMBOL(…);

#ifndef CONFIG_DEBUG_LOCK_ALLOC
#define __raw_write_lock_nested …
#endif

void __lockfunc _raw_write_lock_nested(rwlock_t *lock, int subclass)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_WRITE_LOCK_IRQSAVE
noinline unsigned long __lockfunc _raw_write_lock_irqsave(rwlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_WRITE_LOCK_IRQ
noinline void __lockfunc _raw_write_lock_irq(rwlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_WRITE_LOCK_BH
noinline void __lockfunc _raw_write_lock_bh(rwlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_WRITE_UNLOCK
noinline void __lockfunc _raw_write_unlock(rwlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQRESTORE
noinline void __lockfunc _raw_write_unlock_irqrestore(rwlock_t *lock, unsigned long flags)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_WRITE_UNLOCK_IRQ
noinline void __lockfunc _raw_write_unlock_irq(rwlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef CONFIG_INLINE_WRITE_UNLOCK_BH
noinline void __lockfunc _raw_write_unlock_bh(rwlock_t *lock)
{ … }
EXPORT_SYMBOL(…);
#endif

#endif /* !CONFIG_PREEMPT_RT */

#ifdef CONFIG_DEBUG_LOCK_ALLOC

void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
{ … }
EXPORT_SYMBOL(…);

unsigned long __lockfunc _raw_spin_lock_irqsave_nested(raw_spinlock_t *lock,
						   int subclass)
{ … }
EXPORT_SYMBOL(…);

void __lockfunc _raw_spin_lock_nest_lock(raw_spinlock_t *lock,
				     struct lockdep_map *nest_lock)
{ … }
EXPORT_SYMBOL(…);

#endif

notrace int in_lock_functions(unsigned long addr)
{ … }
EXPORT_SYMBOL(…);

#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_PREEMPT_RT)
void notrace lockdep_assert_in_softirq_func(void)
{
	lockdep_assert_in_softirq();
}
EXPORT_SYMBOL(lockdep_assert_in_softirq_func);
#endif
linux/kernel/locking/spinlock.c
