7cc7eaad49
The ifdeffery for atomic*_{fetch_,}andnot() is unlike that for all the
other atomics. If atomic*_andnot() is not defined, the corresponding
atomic*_fetch_andnot() is assumed to not be defined.
Additionally, the fallbacks for the various ordering cases are written
much later in atomic.h as static inlines.
This isn't problematic today, but gets in the way of scripting the
generation of atomics. To prepare for scripting, this patch:
* Switches to separate ifdefs for atomic*_andnot() and
atomic*_fetch_andnot(), updating implementations as appropriate.
* Moves the fallbacks into the standards ifdefs, as macro expansions
rather than static inlines.
* Removes trivial andnot implementations from architectures, where these
are superseded by core code.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/20180621121321.4761-19-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
562 lines
13 KiB
C
562 lines
13 KiB
C
/*
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* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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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_ARC_ATOMIC_H
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#define _ASM_ARC_ATOMIC_H
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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#include <linux/compiler.h>
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#include <asm/cmpxchg.h>
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#include <asm/barrier.h>
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#include <asm/smp.h>
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#define ATOMIC_INIT(i) { (i) }
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#ifndef CONFIG_ARC_PLAT_EZNPS
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#define atomic_read(v) READ_ONCE((v)->counter)
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#ifdef CONFIG_ARC_HAS_LLSC
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#define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
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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 int val; \
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\
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__asm__ __volatile__( \
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"1: llock %[val], [%[ctr]] \n" \
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" " #asm_op " %[val], %[val], %[i] \n" \
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" scond %[val], [%[ctr]] \n" \
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" bnz 1b \n" \
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: [val] "=&r" (val) /* Early clobber to prevent reg reuse */ \
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: [ctr] "r" (&v->counter), /* Not "m": llock only supports reg direct addr mode */ \
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[i] "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 int val; \
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\
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/* \
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* Explicit full memory barrier needed before/after as \
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* LLOCK/SCOND thmeselves don't provide any such semantics \
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*/ \
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smp_mb(); \
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\
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__asm__ __volatile__( \
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"1: llock %[val], [%[ctr]] \n" \
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" " #asm_op " %[val], %[val], %[i] \n" \
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" scond %[val], [%[ctr]] \n" \
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" bnz 1b \n" \
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: [val] "=&r" (val) \
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: [ctr] "r" (&v->counter), \
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[i] "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 val; \
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}
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#define ATOMIC_FETCH_OP(op, c_op, asm_op) \
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static inline int atomic_fetch_##op(int i, atomic_t *v) \
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{ \
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unsigned int val, orig; \
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\
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/* \
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* Explicit full memory barrier needed before/after as \
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* LLOCK/SCOND thmeselves don't provide any such semantics \
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*/ \
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smp_mb(); \
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\
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__asm__ __volatile__( \
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"1: llock %[orig], [%[ctr]] \n" \
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" " #asm_op " %[val], %[orig], %[i] \n" \
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" scond %[val], [%[ctr]] \n" \
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" \n" \
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: [val] "=&r" (val), \
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[orig] "=&r" (orig) \
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: [ctr] "r" (&v->counter), \
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[i] "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 orig; \
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}
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#else /* !CONFIG_ARC_HAS_LLSC */
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#ifndef CONFIG_SMP
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/* violating atomic_xxx API locking protocol in UP for optimization sake */
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#define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
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#else
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static inline void atomic_set(atomic_t *v, int i)
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{
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/*
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* Independent of hardware support, all of the atomic_xxx() APIs need
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* to follow the same locking rules to make sure that a "hardware"
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* atomic insn (e.g. LD) doesn't clobber an "emulated" atomic insn
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* sequence
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*
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* Thus atomic_set() despite being 1 insn (and seemingly atomic)
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* requires the locking.
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*/
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unsigned long flags;
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atomic_ops_lock(flags);
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WRITE_ONCE(v->counter, i);
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atomic_ops_unlock(flags);
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}
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#define atomic_set_release(v, i) atomic_set((v), (i))
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#endif
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/*
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* Non hardware assisted Atomic-R-M-W
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* Locking would change to irq-disabling only (UP) and spinlocks (SMP)
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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 flags; \
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\
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atomic_ops_lock(flags); \
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v->counter c_op i; \
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atomic_ops_unlock(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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unsigned long temp; \
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\
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/* \
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* spin lock/unlock provides the needed smp_mb() before/after \
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*/ \
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atomic_ops_lock(flags); \
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temp = v->counter; \
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temp c_op i; \
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v->counter = temp; \
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atomic_ops_unlock(flags); \
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\
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return temp; \
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}
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#define ATOMIC_FETCH_OP(op, c_op, asm_op) \
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static inline int atomic_fetch_##op(int i, atomic_t *v) \
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{ \
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unsigned long flags; \
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unsigned long orig; \
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\
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/* \
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* spin lock/unlock provides the needed smp_mb() before/after \
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*/ \
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atomic_ops_lock(flags); \
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orig = v->counter; \
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v->counter c_op i; \
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atomic_ops_unlock(flags); \
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\
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return orig; \
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}
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#endif /* !CONFIG_ARC_HAS_LLSC */
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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_FETCH_OP(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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#define atomic_andnot atomic_andnot
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#define atomic_fetch_andnot atomic_fetch_andnot
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#undef ATOMIC_OPS
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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_FETCH_OP(op, c_op, asm_op)
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ATOMIC_OPS(and, &=, and)
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ATOMIC_OPS(andnot, &= ~, bic)
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ATOMIC_OPS(or, |=, or)
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ATOMIC_OPS(xor, ^=, xor)
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#else /* CONFIG_ARC_PLAT_EZNPS */
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static inline int atomic_read(const atomic_t *v)
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{
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int temp;
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__asm__ __volatile__(
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" ld.di %0, [%1]"
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: "=r"(temp)
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: "r"(&v->counter)
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: "memory");
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return temp;
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}
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static inline void atomic_set(atomic_t *v, int i)
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{
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__asm__ __volatile__(
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" st.di %0,[%1]"
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:
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: "r"(i), "r"(&v->counter)
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: "memory");
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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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__asm__ __volatile__( \
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" mov r2, %0\n" \
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" mov r3, %1\n" \
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" .word %2\n" \
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: \
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: "r"(i), "r"(&v->counter), "i"(asm_op) \
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: "r2", "r3", "memory"); \
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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 int temp = i; \
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\
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/* Explicit full memory barrier needed before/after */ \
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smp_mb(); \
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\
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__asm__ __volatile__( \
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" mov r2, %0\n" \
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" mov r3, %1\n" \
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" .word %2\n" \
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" mov %0, r2" \
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: "+r"(temp) \
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: "r"(&v->counter), "i"(asm_op) \
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: "r2", "r3", "memory"); \
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\
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smp_mb(); \
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\
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temp c_op i; \
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\
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return temp; \
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}
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#define ATOMIC_FETCH_OP(op, c_op, asm_op) \
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static inline int atomic_fetch_##op(int i, atomic_t *v) \
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{ \
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unsigned int temp = i; \
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\
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/* Explicit full memory barrier needed before/after */ \
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smp_mb(); \
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\
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__asm__ __volatile__( \
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" mov r2, %0\n" \
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" mov r3, %1\n" \
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" .word %2\n" \
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" mov %0, r2" \
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: "+r"(temp) \
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: "r"(&v->counter), "i"(asm_op) \
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: "r2", "r3", "memory"); \
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\
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smp_mb(); \
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\
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return temp; \
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}
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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_FETCH_OP(op, c_op, asm_op)
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ATOMIC_OPS(add, +=, CTOP_INST_AADD_DI_R2_R2_R3)
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#define atomic_sub(i, v) atomic_add(-(i), (v))
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#define atomic_sub_return(i, v) atomic_add_return(-(i), (v))
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#define atomic_fetch_sub(i, v) atomic_fetch_add(-(i), (v))
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#undef ATOMIC_OPS
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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_FETCH_OP(op, c_op, asm_op)
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ATOMIC_OPS(and, &=, CTOP_INST_AAND_DI_R2_R2_R3)
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ATOMIC_OPS(or, |=, CTOP_INST_AOR_DI_R2_R2_R3)
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ATOMIC_OPS(xor, ^=, CTOP_INST_AXOR_DI_R2_R2_R3)
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#endif /* CONFIG_ARC_PLAT_EZNPS */
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#undef ATOMIC_OPS
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#undef ATOMIC_FETCH_OP
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#undef ATOMIC_OP_RETURN
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#undef ATOMIC_OP
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#ifdef CONFIG_GENERIC_ATOMIC64
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#include <asm-generic/atomic64.h>
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#else /* Kconfig ensures this is only enabled with needed h/w assist */
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/*
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* ARCv2 supports 64-bit exclusive load (LLOCKD) / store (SCONDD)
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* - The address HAS to be 64-bit aligned
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* - There are 2 semantics involved here:
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* = exclusive implies no interim update between load/store to same addr
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* = both words are observed/updated together: this is guaranteed even
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* for regular 64-bit load (LDD) / store (STD). Thus atomic64_set()
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* is NOT required to use LLOCKD+SCONDD, STD suffices
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*/
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typedef struct {
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aligned_u64 counter;
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} atomic64_t;
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#define ATOMIC64_INIT(a) { (a) }
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static inline long long atomic64_read(const atomic64_t *v)
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{
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unsigned long long val;
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__asm__ __volatile__(
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" ldd %0, [%1] \n"
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: "=r"(val)
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: "r"(&v->counter));
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return val;
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}
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static inline void atomic64_set(atomic64_t *v, long long a)
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{
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/*
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* This could have been a simple assignment in "C" but would need
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* explicit volatile. Otherwise gcc optimizers could elide the store
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* which borked atomic64 self-test
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* In the inline asm version, memory clobber needed for exact same
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* reason, to tell gcc about the store.
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*
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* This however is not needed for sibling atomic64_add() etc since both
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* load/store are explicitly done in inline asm. As long as API is used
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* for each access, gcc has no way to optimize away any load/store
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*/
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__asm__ __volatile__(
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" std %0, [%1] \n"
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:
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: "r"(a), "r"(&v->counter)
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: "memory");
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}
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#define ATOMIC64_OP(op, op1, op2) \
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static inline void atomic64_##op(long long a, atomic64_t *v) \
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{ \
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unsigned long long val; \
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\
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__asm__ __volatile__( \
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"1: \n" \
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" llockd %0, [%1] \n" \
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" " #op1 " %L0, %L0, %L2 \n" \
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" " #op2 " %H0, %H0, %H2 \n" \
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" scondd %0, [%1] \n" \
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" bnz 1b \n" \
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: "=&r"(val) \
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: "r"(&v->counter), "ir"(a) \
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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 a, atomic64_t *v) \
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{ \
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unsigned long long val; \
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\
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smp_mb(); \
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\
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__asm__ __volatile__( \
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"1: \n" \
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" llockd %0, [%1] \n" \
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" " #op1 " %L0, %L0, %L2 \n" \
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" " #op2 " %H0, %H0, %H2 \n" \
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" scondd %0, [%1] \n" \
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" bnz 1b \n" \
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: [val] "=&r"(val) \
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: "r"(&v->counter), "ir"(a) \
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: "cc"); /* memory clobber comes from smp_mb() */ \
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\
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smp_mb(); \
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\
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return val; \
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}
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#define ATOMIC64_FETCH_OP(op, op1, op2) \
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static inline long long atomic64_fetch_##op(long long a, atomic64_t *v) \
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{ \
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unsigned long long val, orig; \
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\
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smp_mb(); \
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\
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__asm__ __volatile__( \
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"1: \n" \
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" llockd %0, [%2] \n" \
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" " #op1 " %L1, %L0, %L3 \n" \
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" " #op2 " %H1, %H0, %H3 \n" \
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" scondd %1, [%2] \n" \
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" bnz 1b \n" \
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: "=&r"(orig), "=&r"(val) \
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: "r"(&v->counter), "ir"(a) \
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: "cc"); /* memory clobber comes from smp_mb() */ \
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\
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smp_mb(); \
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\
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return orig; \
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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_FETCH_OP(op, op1, op2)
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#define atomic64_andnot atomic64_andnot
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#define atomic64_fetch_andnot atomic64_fetch_andnot
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ATOMIC64_OPS(add, add.f, adc)
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ATOMIC64_OPS(sub, sub.f, sbc)
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ATOMIC64_OPS(and, and, and)
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ATOMIC64_OPS(andnot, bic, bic)
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ATOMIC64_OPS(or, or, or)
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ATOMIC64_OPS(xor, xor, xor)
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#undef ATOMIC64_OPS
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#undef ATOMIC64_FETCH_OP
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#undef ATOMIC64_OP_RETURN
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#undef ATOMIC64_OP
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static inline long long
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atomic64_cmpxchg(atomic64_t *ptr, long long expected, long long new)
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{
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long long prev;
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smp_mb();
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__asm__ __volatile__(
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"1: llockd %0, [%1] \n"
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" brne %L0, %L2, 2f \n"
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" brne %H0, %H2, 2f \n"
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" scondd %3, [%1] \n"
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" bnz 1b \n"
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"2: \n"
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: "=&r"(prev)
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: "r"(ptr), "ir"(expected), "r"(new)
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: "cc"); /* memory clobber comes from smp_mb() */
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smp_mb();
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return prev;
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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 prev;
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smp_mb();
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|
|
|
__asm__ __volatile__(
|
|
"1: llockd %0, [%1] \n"
|
|
" scondd %2, [%1] \n"
|
|
" bnz 1b \n"
|
|
"2: \n"
|
|
: "=&r"(prev)
|
|
: "r"(ptr), "r"(new)
|
|
: "cc"); /* memory clobber comes from smp_mb() */
|
|
|
|
smp_mb();
|
|
|
|
return prev;
|
|
}
|
|
|
|
/**
|
|
* atomic64_dec_if_positive - decrement by 1 if old value positive
|
|
* @v: pointer of type atomic64_t
|
|
*
|
|
* The function returns the old value of *v minus 1, even if
|
|
* the atomic variable, v, was not decremented.
|
|
*/
|
|
|
|
static inline long long atomic64_dec_if_positive(atomic64_t *v)
|
|
{
|
|
long long val;
|
|
|
|
smp_mb();
|
|
|
|
__asm__ __volatile__(
|
|
"1: llockd %0, [%1] \n"
|
|
" sub.f %L0, %L0, 1 # w0 - 1, set C on borrow\n"
|
|
" sub.c %H0, %H0, 1 # if C set, w1 - 1\n"
|
|
" brlt %H0, 0, 2f \n"
|
|
" scondd %0, [%1] \n"
|
|
" bnz 1b \n"
|
|
"2: \n"
|
|
: "=&r"(val)
|
|
: "r"(&v->counter)
|
|
: "cc"); /* memory clobber comes from smp_mb() */
|
|
|
|
smp_mb();
|
|
|
|
return val;
|
|
}
|
|
#define atomic64_dec_if_positive atomic64_dec_if_positive
|
|
|
|
/**
|
|
* atomic64_fetch_add_unless - add unless the number is a given value
|
|
* @v: pointer of type atomic64_t
|
|
* @a: the amount to add to v...
|
|
* @u: ...unless v is equal to u.
|
|
*
|
|
* Atomically adds @a to @v, if it was not @u.
|
|
* Returns the old value of @v
|
|
*/
|
|
static inline long long atomic64_fetch_add_unless(atomic64_t *v, long long a,
|
|
long long u)
|
|
{
|
|
long long old, temp;
|
|
|
|
smp_mb();
|
|
|
|
__asm__ __volatile__(
|
|
"1: llockd %0, [%2] \n"
|
|
" brne %L0, %L4, 2f # continue to add since v != u \n"
|
|
" breq.d %H0, %H4, 3f # return since v == u \n"
|
|
"2: \n"
|
|
" add.f %L1, %L0, %L3 \n"
|
|
" adc %H1, %H0, %H3 \n"
|
|
" scondd %1, [%2] \n"
|
|
" bnz 1b \n"
|
|
"3: \n"
|
|
: "=&r"(old), "=&r" (temp)
|
|
: "r"(&v->counter), "r"(a), "r"(u)
|
|
: "cc"); /* memory clobber comes from smp_mb() */
|
|
|
|
smp_mb();
|
|
|
|
return old;
|
|
}
|
|
#define atomic64_fetch_add_unless atomic64_fetch_add_unless
|
|
|
|
#endif /* !CONFIG_GENERIC_ATOMIC64 */
|
|
|
|
#endif /* !__ASSEMBLY__ */
|
|
|
|
#endif
|