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3a74e62ec4
Extract common interface to include/lib/spinlock.h, and invoke the variant implementation of arch. Refine assemble macro code in case that ASSEMBLER defined. Tracked-On: #8803 Signed-off-by: Haoyu Tang <haoyu.tang@intel.com> Reviewed-by: Yifan Liu <yifan1.liu@intel.com> Acked-by: Wang, Yu1 <yu1.wang@intel.com>
75 lines
1.8 KiB
C
75 lines
1.8 KiB
C
/*
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* Copyright (C) 2018-2025 Intel Corporation.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#ifndef X86_LIB_SPINLOCK_H
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#define X86_LIB_SPINLOCK_H
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#ifndef ASSEMBLER
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/** The architecture dependent spinlock type. */
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typedef struct _arch_spinlock {
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uint32_t head;
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uint32_t tail;
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} arch_spinlock_t;
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static inline void arch_spinlock_obtain(arch_spinlock_t *lock)
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{
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/* The lock function atomically increments and exchanges the head
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* counter of the queue. If the old head of the queue is equal to the
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* tail, we have locked the spinlock. Otherwise we have to wait.
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*/
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asm volatile (" movl $0x1,%%eax\n"
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" lock xaddl %%eax,%[head]\n"
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" cmpl %%eax,%[tail]\n"
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" jz 1f\n"
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"2: pause\n"
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" cmpl %%eax,%[tail]\n"
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" jnz 2b\n"
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"1:\n"
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:
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:
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[head] "m"(lock->head),
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[tail] "m"(lock->tail)
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: "cc", "memory", "eax");
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}
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static inline void arch_spinlock_release(arch_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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}
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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 arch_spinlock_obtain lock_arg
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movl $1, % eax
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lea \lock_arg, % 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 arch_spinlock_obtain(x) arch_spinlock_obtain lock_arg = (x)
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.macro arch_spinlock_release lock_arg
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lea \lock_arg, % rbx
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lock incl SYNC_SPINLOCK_TAIL_OFFSET(%rbx)
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.endm
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#define arch_spinlock_release(x) arch_spinlock_release lock_arg = (x)
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#endif /* ASSEMBLER */
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#endif /* X86_LIB_SPINLOCK_H */
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