diff options
Diffstat (limited to 'arch/riscv/include/asm/spinlock.h')
| -rw-r--r-- | arch/riscv/include/asm/spinlock.h | 163 |
1 files changed, 35 insertions, 128 deletions
diff --git a/arch/riscv/include/asm/spinlock.h b/arch/riscv/include/asm/spinlock.h index 8eb26d1ede81..52f11bfd0079 100644 --- a/arch/riscv/include/asm/spinlock.h +++ b/arch/riscv/include/asm/spinlock.h @@ -1,143 +1,50 @@ -/* - * Copyright (C) 2015 Regents of the University of California - * Copyright (C) 2017 SiFive - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation, version 2. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - */ +/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _ASM_RISCV_SPINLOCK_H -#define _ASM_RISCV_SPINLOCK_H +#ifndef __ASM_RISCV_SPINLOCK_H +#define __ASM_RISCV_SPINLOCK_H -#include <linux/kernel.h> -#include <asm/current.h> -#include <asm/fence.h> +#ifdef CONFIG_QUEUED_SPINLOCKS +#define _Q_PENDING_LOOPS (1 << 9) +#endif -/* - * Simple spin lock operations. These provide no fairness guarantees. - */ +#ifdef CONFIG_RISCV_COMBO_SPINLOCKS -/* FIXME: Replace this with a ticket lock, like MIPS. */ - -#define arch_spin_is_locked(x) (READ_ONCE((x)->lock) != 0) - -static inline void arch_spin_unlock(arch_spinlock_t *lock) -{ - smp_store_release(&lock->lock, 0); -} +#define __no_arch_spinlock_redefine +#include <asm/ticket_spinlock.h> +#include <asm/qspinlock.h> +#include <asm/jump_label.h> -static inline int arch_spin_trylock(arch_spinlock_t *lock) -{ - int tmp = 1, busy; - - __asm__ __volatile__ ( - " amoswap.w %0, %2, %1\n" - RISCV_ACQUIRE_BARRIER - : "=r" (busy), "+A" (lock->lock) - : "r" (tmp) - : "memory"); - - return !busy; -} - -static inline void arch_spin_lock(arch_spinlock_t *lock) -{ - while (1) { - if (arch_spin_is_locked(lock)) - continue; - - if (arch_spin_trylock(lock)) - break; - } -} - -/***********************************************************/ - -static inline void arch_read_lock(arch_rwlock_t *lock) -{ - int tmp; - - __asm__ __volatile__( - "1: lr.w %1, %0\n" - " bltz %1, 1b\n" - " addi %1, %1, 1\n" - " sc.w %1, %1, %0\n" - " bnez %1, 1b\n" - RISCV_ACQUIRE_BARRIER - : "+A" (lock->lock), "=&r" (tmp) - :: "memory"); -} - -static inline void arch_write_lock(arch_rwlock_t *lock) -{ - int tmp; +/* + * TODO: Use an alternative instead of a static key when we are able to parse + * the extensions string earlier in the boot process. + */ +DECLARE_STATIC_KEY_TRUE(qspinlock_key); - __asm__ __volatile__( - "1: lr.w %1, %0\n" - " bnez %1, 1b\n" - " li %1, -1\n" - " sc.w %1, %1, %0\n" - " bnez %1, 1b\n" - RISCV_ACQUIRE_BARRIER - : "+A" (lock->lock), "=&r" (tmp) - :: "memory"); +#define SPINLOCK_BASE_DECLARE(op, type, type_lock) \ +static __always_inline type arch_spin_##op(type_lock lock) \ +{ \ + if (static_branch_unlikely(&qspinlock_key)) \ + return queued_spin_##op(lock); \ + return ticket_spin_##op(lock); \ } -static inline int arch_read_trylock(arch_rwlock_t *lock) -{ - int busy; - - __asm__ __volatile__( - "1: lr.w %1, %0\n" - " bltz %1, 1f\n" - " addi %1, %1, 1\n" - " sc.w %1, %1, %0\n" - " bnez %1, 1b\n" - RISCV_ACQUIRE_BARRIER - "1:\n" - : "+A" (lock->lock), "=&r" (busy) - :: "memory"); +SPINLOCK_BASE_DECLARE(lock, void, arch_spinlock_t *) +SPINLOCK_BASE_DECLARE(unlock, void, arch_spinlock_t *) +SPINLOCK_BASE_DECLARE(is_locked, int, arch_spinlock_t *) +SPINLOCK_BASE_DECLARE(is_contended, int, arch_spinlock_t *) +SPINLOCK_BASE_DECLARE(trylock, bool, arch_spinlock_t *) +SPINLOCK_BASE_DECLARE(value_unlocked, int, arch_spinlock_t) - return !busy; -} +#elif defined(CONFIG_RISCV_QUEUED_SPINLOCKS) -static inline int arch_write_trylock(arch_rwlock_t *lock) -{ - int busy; +#include <asm/qspinlock.h> - __asm__ __volatile__( - "1: lr.w %1, %0\n" - " bnez %1, 1f\n" - " li %1, -1\n" - " sc.w %1, %1, %0\n" - " bnez %1, 1b\n" - RISCV_ACQUIRE_BARRIER - "1:\n" - : "+A" (lock->lock), "=&r" (busy) - :: "memory"); +#else - return !busy; -} +#include <asm/ticket_spinlock.h> -static inline void arch_read_unlock(arch_rwlock_t *lock) -{ - __asm__ __volatile__( - RISCV_RELEASE_BARRIER - " amoadd.w x0, %1, %0\n" - : "+A" (lock->lock) - : "r" (-1) - : "memory"); -} +#endif -static inline void arch_write_unlock(arch_rwlock_t *lock) -{ - smp_store_release(&lock->lock, 0); -} +#include <asm/qrwlock.h> -#endif /* _ASM_RISCV_SPINLOCK_H */ +#endif /* __ASM_RISCV_SPINLOCK_H */ |