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79 lines
2.0 KiB
79 lines
2.0 KiB
7 years ago
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// See LICENSE for license details.
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#ifndef _RISCV_ATOMIC_H
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#define _RISCV_ATOMIC_H
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#include "config.h"
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#include "encoding.h"
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// Currently, interrupts are always disabled in M-mode.
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#define disable_irqsave() (0)
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#define enable_irqrestore(flags) ((void) (flags))
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typedef struct { int lock; } spinlock_t;
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#define SPINLOCK_INIT {0}
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#define mb() asm volatile ("fence" ::: "memory")
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#define atomic_set(ptr, val) (*(volatile typeof(*(ptr)) *)(ptr) = val)
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#define atomic_read(ptr) (*(volatile typeof(*(ptr)) *)(ptr))
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#ifdef __riscv_atomic
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# define atomic_add(ptr, inc) __sync_fetch_and_add(ptr, inc)
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# define atomic_or(ptr, inc) __sync_fetch_and_or(ptr, inc)
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# define atomic_swap(ptr, swp) __sync_lock_test_and_set(ptr, swp)
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# define atomic_cas(ptr, cmp, swp) __sync_val_compare_and_swap(ptr, cmp, swp)
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#else
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# define atomic_binop(ptr, inc, op) ({ \
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long flags = disable_irqsave(); \
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typeof(*(ptr)) res = atomic_read(ptr); \
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atomic_set(ptr, op); \
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enable_irqrestore(flags); \
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res; })
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# define atomic_add(ptr, inc) atomic_binop(ptr, inc, res + (inc))
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# define atomic_or(ptr, inc) atomic_binop(ptr, inc, res | (inc))
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# define atomic_swap(ptr, inc) atomic_binop(ptr, inc, (inc))
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# define atomic_cas(ptr, cmp, swp) ({ \
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long flags = disable_irqsave(); \
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typeof(*(ptr)) res = *(volatile typeof(*(ptr)) *)(ptr); \
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if (res == (cmp)) *(volatile typeof(ptr))(ptr) = (swp); \
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enable_irqrestore(flags); \
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res; })
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#endif
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static inline int spinlock_trylock(spinlock_t* lock)
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{
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int res = atomic_swap(&lock->lock, -1);
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mb();
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return res;
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}
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static inline void spinlock_lock(spinlock_t* lock)
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{
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do
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{
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while (atomic_read(&lock->lock))
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;
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} while (spinlock_trylock(lock));
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}
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static inline void spinlock_unlock(spinlock_t* lock)
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{
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mb();
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atomic_set(&lock->lock,0);
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}
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static inline long spinlock_lock_irqsave(spinlock_t* lock)
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{
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long flags = disable_irqsave();
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spinlock_lock(lock);
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return flags;
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}
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static inline void spinlock_unlock_irqrestore(spinlock_t* lock, long flags)
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{
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spinlock_unlock(lock);
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enable_irqrestore(flags);
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}
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#endif
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