447 lines
9.9 KiB
C
447 lines
9.9 KiB
C
/*
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* arch/arm/include/asm/atomic.h
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*
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* Copyright (C) 1996 Russell King.
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* Copyright (C) 2002 Deep Blue Solutions Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef __ASM_ARM_ATOMIC_H
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#define __ASM_ARM_ATOMIC_H
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#include <linux/compiler.h>
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#include <linux/prefetch.h>
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#include <linux/types.h>
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#include <linux/irqflags.h>
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#include <asm/barrier.h>
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#include <asm/cmpxchg.h>
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#define ATOMIC_INIT(i) { (i) }
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#ifdef __KERNEL__
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/*
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* On ARM, ordinary assignment (str instruction) doesn't clear the local
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* strex/ldrex monitor on some implementations. The reason we can use it for
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* atomic_set() is the clrex or dummy strex done on every exception return.
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*/
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#define atomic_read(v) ACCESS_ONCE((v)->counter)
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#define atomic_set(v,i) (((v)->counter) = (i))
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#if __LINUX_ARM_ARCH__ >= 6
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/*
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* ARMv6 UP and SMP safe atomic ops. We use load exclusive and
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* store exclusive to ensure that these are atomic. We may loop
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* to ensure that the update happens.
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*/
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#define ATOMIC_OP(op, c_op, asm_op) \
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static inline void atomic_##op(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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\
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prefetchw(&v->counter); \
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__asm__ __volatile__("@ atomic_" #op "\n" \
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"1: ldrex %0, [%3]\n" \
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" " #asm_op " %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" \
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: "=&r" (result), "=&r" (tmp), "+Qo" (v->counter) \
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: "r" (&v->counter), "Ir" (i) \
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: "cc"); \
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} \
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#define ATOMIC_OP_RETURN(op, c_op, asm_op) \
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static inline int atomic_##op##_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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\
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smp_mb(); \
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prefetchw(&v->counter); \
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\
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__asm__ __volatile__("@ atomic_" #op "_return\n" \
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"1: ldrex %0, [%3]\n" \
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" " #asm_op " %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" \
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: "=&r" (result), "=&r" (tmp), "+Qo" (v->counter) \
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: "r" (&v->counter), "Ir" (i) \
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: "cc"); \
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\
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smp_mb(); \
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\
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return result; \
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}
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static inline int atomic_cmpxchg(atomic_t *ptr, int old, int new)
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{
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int oldval;
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unsigned long res;
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smp_mb();
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prefetchw(&ptr->counter);
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do {
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__asm__ __volatile__("@ atomic_cmpxchg\n"
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"ldrex %1, [%3]\n"
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"mov %0, #0\n"
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"teq %1, %4\n"
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"strexeq %0, %5, [%3]\n"
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: "=&r" (res), "=&r" (oldval), "+Qo" (ptr->counter)
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: "r" (&ptr->counter), "Ir" (old), "r" (new)
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: "cc");
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} while (res);
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smp_mb();
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return oldval;
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}
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static inline int __atomic_add_unless(atomic_t *v, int a, int u)
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{
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int oldval, newval;
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unsigned long tmp;
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smp_mb();
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prefetchw(&v->counter);
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__asm__ __volatile__ ("@ atomic_add_unless\n"
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"1: ldrex %0, [%4]\n"
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" teq %0, %5\n"
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" beq 2f\n"
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" add %1, %0, %6\n"
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" strex %2, %1, [%4]\n"
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" teq %2, #0\n"
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" bne 1b\n"
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"2:"
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: "=&r" (oldval), "=&r" (newval), "=&r" (tmp), "+Qo" (v->counter)
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: "r" (&v->counter), "r" (u), "r" (a)
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: "cc");
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if (oldval != u)
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smp_mb();
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return oldval;
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}
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#else /* ARM_ARCH_6 */
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#ifdef CONFIG_SMP
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#error SMP not supported on pre-ARMv6 CPUs
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#endif
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#define ATOMIC_OP(op, c_op, asm_op) \
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static inline void atomic_##op(int i, atomic_t *v) \
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{ \
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unsigned long flags; \
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\
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raw_local_irq_save(flags); \
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v->counter c_op i; \
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raw_local_irq_restore(flags); \
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} \
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#define ATOMIC_OP_RETURN(op, c_op, asm_op) \
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static inline int atomic_##op##_return(int i, atomic_t *v) \
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{ \
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unsigned long flags; \
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int val; \
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\
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raw_local_irq_save(flags); \
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v->counter c_op i; \
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val = v->counter; \
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raw_local_irq_restore(flags); \
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\
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return val; \
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}
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static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
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{
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int ret;
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unsigned long flags;
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raw_local_irq_save(flags);
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ret = v->counter;
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if (likely(ret == old))
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v->counter = new;
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raw_local_irq_restore(flags);
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return ret;
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}
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static inline int __atomic_add_unless(atomic_t *v, int a, int u)
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{
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int c, old;
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c = atomic_read(v);
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while (c != u && (old = atomic_cmpxchg((v), c, c + a)) != c)
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c = old;
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return c;
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}
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#endif /* __LINUX_ARM_ARCH__ */
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#define ATOMIC_OPS(op, c_op, asm_op) \
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ATOMIC_OP(op, c_op, asm_op) \
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ATOMIC_OP_RETURN(op, c_op, asm_op)
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ATOMIC_OPS(add, +=, add)
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ATOMIC_OPS(sub, -=, sub)
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#undef ATOMIC_OPS
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#undef ATOMIC_OP_RETURN
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#undef ATOMIC_OP
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#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
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#define atomic_inc(v) atomic_add(1, v)
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#define atomic_dec(v) atomic_sub(1, v)
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#define atomic_inc_and_test(v) (atomic_add_return(1, v) == 0)
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#define atomic_dec_and_test(v) (atomic_sub_return(1, v) == 0)
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#define atomic_inc_return(v) (atomic_add_return(1, v))
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#define atomic_dec_return(v) (atomic_sub_return(1, v))
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#define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0)
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#define atomic_add_negative(i,v) (atomic_add_return(i, v) < 0)
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#ifndef CONFIG_GENERIC_ATOMIC64
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typedef struct {
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long long counter;
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} atomic64_t;
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#define ATOMIC64_INIT(i) { (i) }
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#ifdef CONFIG_ARM_LPAE
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static inline long long atomic64_read(const atomic64_t *v)
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{
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long long result;
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__asm__ __volatile__("@ atomic64_read\n"
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" ldrd %0, %H0, [%1]"
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: "=&r" (result)
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: "r" (&v->counter), "Qo" (v->counter)
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);
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return result;
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}
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static inline void atomic64_set(atomic64_t *v, long long i)
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{
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__asm__ __volatile__("@ atomic64_set\n"
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" strd %2, %H2, [%1]"
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: "=Qo" (v->counter)
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: "r" (&v->counter), "r" (i)
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);
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}
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#else
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static inline long long atomic64_read(const atomic64_t *v)
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{
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long long result;
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__asm__ __volatile__("@ atomic64_read\n"
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" ldrexd %0, %H0, [%1]"
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: "=&r" (result)
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: "r" (&v->counter), "Qo" (v->counter)
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);
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return result;
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}
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static inline void atomic64_set(atomic64_t *v, long long i)
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{
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long long tmp;
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prefetchw(&v->counter);
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__asm__ __volatile__("@ atomic64_set\n"
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"1: ldrexd %0, %H0, [%2]\n"
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" strexd %0, %3, %H3, [%2]\n"
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" teq %0, #0\n"
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" bne 1b"
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: "=&r" (tmp), "=Qo" (v->counter)
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: "r" (&v->counter), "r" (i)
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: "cc");
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}
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#endif
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#define ATOMIC64_OP(op, op1, op2) \
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static inline void atomic64_##op(long long i, atomic64_t *v) \
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{ \
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long long result; \
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unsigned long tmp; \
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\
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prefetchw(&v->counter); \
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__asm__ __volatile__("@ atomic64_" #op "\n" \
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"1: ldrexd %0, %H0, [%3]\n" \
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" " #op1 " %Q0, %Q0, %Q4\n" \
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" " #op2 " %R0, %R0, %R4\n" \
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" strexd %1, %0, %H0, [%3]\n" \
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" teq %1, #0\n" \
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" bne 1b" \
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: "=&r" (result), "=&r" (tmp), "+Qo" (v->counter) \
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: "r" (&v->counter), "r" (i) \
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: "cc"); \
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} \
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#define ATOMIC64_OP_RETURN(op, op1, op2) \
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static inline long long atomic64_##op##_return(long long i, atomic64_t *v) \
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{ \
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long long result; \
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unsigned long tmp; \
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\
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smp_mb(); \
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prefetchw(&v->counter); \
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\
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__asm__ __volatile__("@ atomic64_" #op "_return\n" \
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"1: ldrexd %0, %H0, [%3]\n" \
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" " #op1 " %Q0, %Q0, %Q4\n" \
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" " #op2 " %R0, %R0, %R4\n" \
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" strexd %1, %0, %H0, [%3]\n" \
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" teq %1, #0\n" \
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" bne 1b" \
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: "=&r" (result), "=&r" (tmp), "+Qo" (v->counter) \
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: "r" (&v->counter), "r" (i) \
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: "cc"); \
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\
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smp_mb(); \
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\
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return result; \
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}
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#define ATOMIC64_OPS(op, op1, op2) \
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ATOMIC64_OP(op, op1, op2) \
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ATOMIC64_OP_RETURN(op, op1, op2)
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ATOMIC64_OPS(add, adds, adc)
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ATOMIC64_OPS(sub, subs, sbc)
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#undef ATOMIC64_OPS
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#undef ATOMIC64_OP_RETURN
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#undef ATOMIC64_OP
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static inline long long atomic64_cmpxchg(atomic64_t *ptr, long long old,
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long long new)
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{
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long long oldval;
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unsigned long res;
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smp_mb();
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prefetchw(&ptr->counter);
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do {
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__asm__ __volatile__("@ atomic64_cmpxchg\n"
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"ldrexd %1, %H1, [%3]\n"
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"mov %0, #0\n"
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"teq %1, %4\n"
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"teqeq %H1, %H4\n"
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"strexdeq %0, %5, %H5, [%3]"
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: "=&r" (res), "=&r" (oldval), "+Qo" (ptr->counter)
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: "r" (&ptr->counter), "r" (old), "r" (new)
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: "cc");
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} while (res);
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smp_mb();
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return oldval;
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}
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static inline long long atomic64_xchg(atomic64_t *ptr, long long new)
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{
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long long result;
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unsigned long tmp;
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smp_mb();
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prefetchw(&ptr->counter);
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__asm__ __volatile__("@ atomic64_xchg\n"
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"1: ldrexd %0, %H0, [%3]\n"
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" strexd %1, %4, %H4, [%3]\n"
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" teq %1, #0\n"
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" bne 1b"
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: "=&r" (result), "=&r" (tmp), "+Qo" (ptr->counter)
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: "r" (&ptr->counter), "r" (new)
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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 long long atomic64_dec_if_positive(atomic64_t *v)
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{
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long long result;
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unsigned long tmp;
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smp_mb();
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prefetchw(&v->counter);
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__asm__ __volatile__("@ atomic64_dec_if_positive\n"
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"1: ldrexd %0, %H0, [%3]\n"
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" subs %Q0, %Q0, #1\n"
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" sbc %R0, %R0, #0\n"
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" teq %R0, #0\n"
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" bmi 2f\n"
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" strexd %1, %0, %H0, [%3]\n"
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" teq %1, #0\n"
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" bne 1b\n"
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"2:"
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: "=&r" (result), "=&r" (tmp), "+Qo" (v->counter)
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: "r" (&v->counter)
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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 int atomic64_add_unless(atomic64_t *v, long long a, long long u)
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{
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long long val;
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unsigned long tmp;
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int ret = 1;
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smp_mb();
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prefetchw(&v->counter);
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__asm__ __volatile__("@ atomic64_add_unless\n"
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"1: ldrexd %0, %H0, [%4]\n"
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" teq %0, %5\n"
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" teqeq %H0, %H5\n"
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" moveq %1, #0\n"
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" beq 2f\n"
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" adds %Q0, %Q0, %Q6\n"
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" adc %R0, %R0, %R6\n"
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" strexd %2, %0, %H0, [%4]\n"
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" teq %2, #0\n"
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" bne 1b\n"
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"2:"
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: "=&r" (val), "+r" (ret), "=&r" (tmp), "+Qo" (v->counter)
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: "r" (&v->counter), "r" (u), "r" (a)
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: "cc");
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if (ret)
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smp_mb();
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return ret;
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}
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#define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0)
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#define atomic64_inc(v) atomic64_add(1LL, (v))
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#define atomic64_inc_return(v) atomic64_add_return(1LL, (v))
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#define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0)
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#define atomic64_sub_and_test(a, v) (atomic64_sub_return((a), (v)) == 0)
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#define atomic64_dec(v) atomic64_sub(1LL, (v))
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#define atomic64_dec_return(v) atomic64_sub_return(1LL, (v))
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#define atomic64_dec_and_test(v) (atomic64_dec_return((v)) == 0)
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#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1LL, 0LL)
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#endif /* !CONFIG_GENERIC_ATOMIC64 */
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#endif
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#endif
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