cregit-Linux how code gets into the kernel

Release 4.14 arch/sh/include/asm/spinlock-cas.h

/*
 * include/asm-sh/spinlock-cas.h
 *
 * Copyright (C) 2015 SEI
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#ifndef __ASM_SH_SPINLOCK_CAS_H

#define __ASM_SH_SPINLOCK_CAS_H

#include <asm/barrier.h>
#include <asm/processor.h>


static inline unsigned __sl_cas(volatile unsigned *p, unsigned old, unsigned new) { __asm__ __volatile__("cas.l %1,%0,@r0" : "+r"(new) : "r"(old), "z"(p) : "t", "memory" ); return new; }

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Rich Felker24100.00%1100.00%
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/* * Your basic SMP spinlocks, allowing only a single CPU anywhere */ #define arch_spin_is_locked(x) ((x)->lock <= 0) #define arch_spin_lock_flags(lock, flags) arch_spin_lock(lock)
static inline void arch_spin_lock(arch_spinlock_t *lock) { while (!__sl_cas(&lock->lock, 1, 0)); }

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static inline void arch_spin_unlock(arch_spinlock_t *lock) { __sl_cas(&lock->lock, 0, 1); }

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Rich Felker23100.00%1100.00%
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static inline int arch_spin_trylock(arch_spinlock_t *lock) { return __sl_cas(&lock->lock, 1, 0); }

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Rich Felker24100.00%1100.00%
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/* * 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. */ /** * read_can_lock - would read_trylock() succeed? * @lock: the rwlock in question. */ #define arch_read_can_lock(x) ((x)->lock > 0) /** * write_can_lock - would write_trylock() succeed? * @lock: the rwlock in question. */ #define arch_write_can_lock(x) ((x)->lock == RW_LOCK_BIAS)
static inline void arch_read_lock(arch_rwlock_t *rw) { unsigned old; do old = rw->lock; while (!old || __sl_cas(&rw->lock, old, old-1) != old); }

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Rich Felker43100.00%1100.00%
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static inline void arch_read_unlock(arch_rwlock_t *rw) { unsigned old; do old = rw->lock; while (__sl_cas(&rw->lock, old, old+1) != old); }

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Rich Felker40100.00%1100.00%
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static inline void arch_write_lock(arch_rwlock_t *rw) { while (__sl_cas(&rw->lock, RW_LOCK_BIAS, 0) != RW_LOCK_BIAS); }

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Rich Felker28100.00%1100.00%
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static inline void arch_write_unlock(arch_rwlock_t *rw) { __sl_cas(&rw->lock, 0, RW_LOCK_BIAS); }

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Rich Felker23100.00%1100.00%
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static inline int arch_read_trylock(arch_rwlock_t *rw) { unsigned old; do old = rw->lock; while (old && __sl_cas(&rw->lock, old, old-1) != old); return !!old; }

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Rich Felker47100.00%1100.00%
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static inline int arch_write_trylock(arch_rwlock_t *rw) { return __sl_cas(&rw->lock, RW_LOCK_BIAS, 0) == RW_LOCK_BIAS; }

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Rich Felker26100.00%1100.00%
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#define arch_read_lock_flags(lock, flags) arch_read_lock(lock) #define arch_write_lock_flags(lock, flags) arch_write_lock(lock) #define arch_spin_relax(lock) cpu_relax() #define arch_read_relax(lock) cpu_relax() #define arch_write_relax(lock) cpu_relax() #endif /* __ASM_SH_SPINLOCK_CAS_H */

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Rich Felker394100.00%1100.00%
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