mirror of
https://github.com/checkpoint-restore/criu
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67 lines
1.3 KiB
C
67 lines
1.3 KiB
C
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#ifndef __CR_ATOMIC_H__
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#define __CR_ATOMIC_H__
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typedef uint32_t atomic_t;
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/* Copied from the Linux kernel header arch/arm/include/asm/atomic.h */
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#define smp_mb() __asm__ __volatile__ ("dmb" : : : "memory")
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#define atomic_set(mem,v) (*(mem) = (v))
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#define atomic_get(v) (*(volatile uint32_t *)v)
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static inline unsigned int atomic_add_return(int i, atomic_t *v)
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{
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unsigned long tmp;
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unsigned int result;
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smp_mb();
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__asm__ __volatile__("@ atomic_add_return\n"
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"1: ldrex %0, [%3]\n"
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" add %0, %0, %4\n"
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" strex %1, %0, [%3]\n"
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" teq %1, #0\n"
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" bne 1b\n"
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: "=&r" (result), "=&r" (tmp), "+Qo" (v)
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: "r" (&v), "Ir" (i)
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: "cc");
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smp_mb();
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return result;
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}
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static inline unsigned int atomic_sub_return(int i, atomic_t *v)
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{
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unsigned long tmp;
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int result;
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smp_mb();
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__asm__ __volatile__("@ atomic_sub_return\n"
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"1: ldrex %0, [%3]\n"
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" sub %0, %0, %4\n"
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" strex %1, %0, [%3]\n"
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" teq %1, #0\n"
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" bne 1b\n"
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: "=&r" (result), "=&r" (tmp), "+Qo" (v)
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: "r" (&v), "Ir" (i)
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: "cc");
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smp_mb();
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return result;
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}
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static inline unsigned int atomic_inc(atomic_t *v) { return atomic_add_return(1, v) - 1; }
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static inline unsigned int atomic_dec(atomic_t *v) { return atomic_sub_return(1, v) + 1; }
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/* true if the result is 0, or false for all other cases. */
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#define atomic_dec_and_test(v) (atomic_sub_return(1, v) == 0)
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#endif /* __CR_ATOMIC_H__ */
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