107 lines
3.0 KiB
C
107 lines
3.0 KiB
C
/*
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* Copyright (C) 2018 Intel Corporation. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Intel Corporation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef SPINLOCK_H
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#define SPINLOCK_H
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#ifndef ASSEMBLER
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#include <types.h>
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/** The architecture dependent spinlock type. */
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typedef struct _spinlock {
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uint32_t head;
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uint32_t tail;
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} spinlock_t;
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/* Function prototypes */
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int spinlock_init(spinlock_t *lock);
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int spinlock_obtain(spinlock_t *lock);
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static inline int spinlock_release(spinlock_t *lock)
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{
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/* Increment tail of queue */
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asm volatile (" lock incl %[tail]\n"
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:
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: [tail] "m" (lock->tail)
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: "cc", "memory");
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return 0;
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}
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#else /* ASSEMBLER */
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/** The offset of the head element. */
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#define SYNC_SPINLOCK_HEAD_OFFSET 0
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/** The offset of the tail element. */
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#define SYNC_SPINLOCK_TAIL_OFFSET 4
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.macro spinlock_obtain lock
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movl $1, % eax
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lea \lock, % rbx
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lock xaddl % eax, SYNC_SPINLOCK_HEAD_OFFSET(%rbx)
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cmpl % eax, SYNC_SPINLOCK_TAIL_OFFSET(%rbx)
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jz 1f
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2 :
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pause
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cmpl % eax, SYNC_SPINLOCK_TAIL_OFFSET(%rbx)
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jnz 2b
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1 :
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.endm
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#define spinlock_obtain(x) spinlock_obtain lock = (x)
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.macro spinlock_release lock
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lea \lock, % rbx
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lock incl SYNC_SPINLOCK_TAIL_OFFSET(%rbx)
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.endm
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#define spinlock_release(x) spinlock_release lock = (x)
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#endif /* ASSEMBLER */
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#define spinlock_rflags unsigned long cpu_int_value
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#define spinlock_irqsave_obtain(l) \
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do { \
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CPU_INT_ALL_DISABLE(); \
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spinlock_obtain((l)); \
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} while (0)
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#define spinlock_irqrestore_release(l) \
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do { \
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spinlock_release((l)); \
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CPU_INT_ALL_RESTORE(); \
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} while (0)
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#endif /* SPINLOCK_H */
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