forked from Mirrors/opensbi
4d8e2f135d
Replace the test-and-set spinlock implementation with ticket locks in order to get fairness (in form of FIFO order). The implementation uses a 32-bit wide struct, which consists of two 16-bit counters (owner and next). This is inspired by similar spinlock implementations on other architectures. This allows that the code works for both, RV32 and RV64. Signed-off-by: Christoph Muellner <cmuellner@linux.com> Reviewed-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Xiang W <wxjstz@126.com>
46 lines
843 B
C
46 lines
843 B
C
/*
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2019 Western Digital Corporation or its affiliates.
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* Copyright (c) 2021 Christoph Müllner <cmuellner@linux.com>
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*/
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#ifndef __RISCV_LOCKS_H__
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#define __RISCV_LOCKS_H__
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#include <sbi/sbi_types.h>
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#define TICKET_SHIFT 16
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typedef struct {
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#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
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u16 next;
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u16 owner;
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#else
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u16 owner;
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u16 next;
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#endif
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} __aligned(4) spinlock_t;
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#define __SPIN_LOCK_UNLOCKED \
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(spinlock_t) { 0, 0 }
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#define SPIN_LOCK_INIT(x) \
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x = __SPIN_LOCK_UNLOCKED
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#define SPIN_LOCK_INITIALIZER \
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__SPIN_LOCK_UNLOCKED
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#define DEFINE_SPIN_LOCK(x) \
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spinlock_t SPIN_LOCK_INIT(x)
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int spin_lock_check(spinlock_t *lock);
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int spin_trylock(spinlock_t *lock);
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void spin_lock(spinlock_t *lock);
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void spin_unlock(spinlock_t *lock);
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#endif
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