diff options
| author | Christoph Muellner <cmuellner@linux.com> | 2021-04-06 03:53:54 +0200 |
|---|---|---|
| committer | Anup Patel <anup@brainfault.org> | 2021-04-09 18:48:50 +0530 |
| commit | 4d8e2f135d659697337f8d4a33fec60cd475f0dc (patch) | |
| tree | 9f1bd8ef91f5b6a52123db13b5f80437e62ba197 /include | |
| parent | d0e406fa44a108210d29b26281777206961cd772 (diff) | |
lib: sbi: Replace test-and-set locks by ticket locks
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>
Diffstat (limited to 'include')
| -rw-r--r-- | include/sbi/riscv_locks.h | 33 |
1 files changed, 22 insertions, 11 deletions
diff --git a/include/sbi/riscv_locks.h b/include/sbi/riscv_locks.h index faa9676..492935f 100644 --- a/include/sbi/riscv_locks.h +++ b/include/sbi/riscv_locks.h @@ -2,26 +2,37 @@ * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2019 Western Digital Corporation or its affiliates. - * - * Authors: - * Anup Patel <anup.patel@wdc.com> + * Copyright (c) 2021 Christoph Müllner <cmuellner@linux.com> */ #ifndef __RISCV_LOCKS_H__ #define __RISCV_LOCKS_H__ +#include <sbi/sbi_types.h> + +#define TICKET_SHIFT 16 + typedef struct { - volatile long lock; -} spinlock_t; +#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ + u16 next; + u16 owner; +#else + u16 owner; + u16 next; +#endif +} __aligned(4) spinlock_t; + +#define __SPIN_LOCK_UNLOCKED \ + (spinlock_t) { 0, 0 } -#define __RISCV_SPIN_UNLOCKED 0 +#define SPIN_LOCK_INIT(x) \ + x = __SPIN_LOCK_UNLOCKED -#define SPIN_LOCK_INIT(x) (x).lock = __RISCV_SPIN_UNLOCKED +#define SPIN_LOCK_INITIALIZER \ + __SPIN_LOCK_UNLOCKED -#define SPIN_LOCK_INITIALIZER \ - { \ - .lock = __RISCV_SPIN_UNLOCKED, \ - } +#define DEFINE_SPIN_LOCK(x) \ + spinlock_t SPIN_LOCK_INIT(x) int spin_lock_check(spinlock_t *lock); |