e6942b7de2
Implement atomic logic ops -- atomic_{or,xor,and}.
These will replace the atomic_{set,clear}_mask functions that are
available on some archs.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
598 lines
16 KiB
C
598 lines
16 KiB
C
/*
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* Atomic operations that C can't guarantee us. Useful for
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* resource counting etc..
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*
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* But use these as seldom as possible since they are much more slower
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* than regular operations.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1996, 97, 99, 2000, 03, 04, 06 by Ralf Baechle
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*/
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#ifndef _ASM_ATOMIC_H
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#define _ASM_ATOMIC_H
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#include <linux/irqflags.h>
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#include <linux/types.h>
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#include <asm/barrier.h>
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#include <asm/compiler.h>
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#include <asm/cpu-features.h>
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#include <asm/cmpxchg.h>
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#include <asm/war.h>
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#define ATOMIC_INIT(i) { (i) }
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/*
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* atomic_read - read atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically reads the value of @v.
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*/
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#define atomic_read(v) ACCESS_ONCE((v)->counter)
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/*
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* atomic_set - set atomic variable
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* @v: pointer of type atomic_t
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* @i: required value
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*
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* Atomically sets the value of @v to @i.
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*/
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#define atomic_set(v, i) ((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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if (kernel_uses_llsc && R10000_LLSC_WAR) { \
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int temp; \
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\
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__asm__ __volatile__( \
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" .set arch=r4000 \n" \
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"1: ll %0, %1 # atomic_" #op " \n" \
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" " #asm_op " %0, %2 \n" \
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" sc %0, %1 \n" \
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" beqzl %0, 1b \n" \
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" .set mips0 \n" \
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: "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (v->counter) \
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: "Ir" (i)); \
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} else if (kernel_uses_llsc) { \
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int temp; \
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\
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do { \
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__asm__ __volatile__( \
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" .set "MIPS_ISA_LEVEL" \n" \
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" ll %0, %1 # atomic_" #op "\n" \
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" " #asm_op " %0, %2 \n" \
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" sc %0, %1 \n" \
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" .set mips0 \n" \
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: "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (v->counter) \
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: "Ir" (i)); \
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} while (unlikely(!temp)); \
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} else { \
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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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}
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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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int result; \
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\
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smp_mb__before_llsc(); \
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\
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if (kernel_uses_llsc && R10000_LLSC_WAR) { \
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int temp; \
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\
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__asm__ __volatile__( \
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" .set arch=r4000 \n" \
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"1: ll %1, %2 # atomic_" #op "_return \n" \
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" " #asm_op " %0, %1, %3 \n" \
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" sc %0, %2 \n" \
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" beqzl %0, 1b \n" \
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" " #asm_op " %0, %1, %3 \n" \
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" .set mips0 \n" \
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: "=&r" (result), "=&r" (temp), \
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"+" GCC_OFF_SMALL_ASM() (v->counter) \
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: "Ir" (i)); \
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} else if (kernel_uses_llsc) { \
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int temp; \
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\
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do { \
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__asm__ __volatile__( \
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" .set "MIPS_ISA_LEVEL" \n" \
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" ll %1, %2 # atomic_" #op "_return \n" \
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" " #asm_op " %0, %1, %3 \n" \
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" sc %0, %2 \n" \
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" .set mips0 \n" \
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: "=&r" (result), "=&r" (temp), \
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"+" GCC_OFF_SMALL_ASM() (v->counter) \
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: "Ir" (i)); \
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} while (unlikely(!result)); \
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\
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result = temp; result c_op i; \
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} else { \
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unsigned long flags; \
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\
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raw_local_irq_save(flags); \
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result = v->counter; \
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result c_op i; \
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v->counter = result; \
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raw_local_irq_restore(flags); \
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} \
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\
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smp_llsc_mb(); \
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\
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return result; \
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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_OPS(add, +=, addu)
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ATOMIC_OPS(sub, -=, subu)
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ATOMIC_OP(and, &=, and)
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ATOMIC_OP(or, |=, or)
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ATOMIC_OP(xor, ^=, xor)
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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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/*
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* atomic_sub_if_positive - conditionally subtract integer from atomic variable
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* @i: integer value to subtract
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* @v: pointer of type atomic_t
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*
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* Atomically test @v and subtract @i if @v is greater or equal than @i.
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* The function returns the old value of @v minus @i.
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*/
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static __inline__ int atomic_sub_if_positive(int i, atomic_t * v)
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{
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int result;
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smp_mb__before_llsc();
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if (kernel_uses_llsc && R10000_LLSC_WAR) {
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int temp;
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__asm__ __volatile__(
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" .set arch=r4000 \n"
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"1: ll %1, %2 # atomic_sub_if_positive\n"
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" subu %0, %1, %3 \n"
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" bltz %0, 1f \n"
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" sc %0, %2 \n"
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" .set noreorder \n"
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" beqzl %0, 1b \n"
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" subu %0, %1, %3 \n"
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" .set reorder \n"
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"1: \n"
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" .set mips0 \n"
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: "=&r" (result), "=&r" (temp),
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"+" GCC_OFF_SMALL_ASM() (v->counter)
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: "Ir" (i), GCC_OFF_SMALL_ASM() (v->counter)
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: "memory");
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} else if (kernel_uses_llsc) {
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int temp;
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__asm__ __volatile__(
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" .set "MIPS_ISA_LEVEL" \n"
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"1: ll %1, %2 # atomic_sub_if_positive\n"
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" subu %0, %1, %3 \n"
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" bltz %0, 1f \n"
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" sc %0, %2 \n"
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" .set noreorder \n"
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" beqz %0, 1b \n"
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" subu %0, %1, %3 \n"
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" .set reorder \n"
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"1: \n"
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" .set mips0 \n"
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: "=&r" (result), "=&r" (temp),
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"+" GCC_OFF_SMALL_ASM() (v->counter)
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: "Ir" (i));
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} else {
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unsigned long flags;
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raw_local_irq_save(flags);
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result = v->counter;
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result -= i;
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if (result >= 0)
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v->counter = result;
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raw_local_irq_restore(flags);
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}
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smp_llsc_mb();
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return result;
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}
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#define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
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#define atomic_xchg(v, new) (xchg(&((v)->counter), (new)))
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/**
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* __atomic_add_unless - add unless the number is a given value
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* @v: pointer of type atomic_t
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* @a: the amount to add to v...
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* @u: ...unless v is equal to u.
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*
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* Atomically adds @a to @v, so long as it was not @u.
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* Returns the old value of @v.
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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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for (;;) {
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if (unlikely(c == (u)))
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break;
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old = atomic_cmpxchg((v), c, c + (a));
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if (likely(old == c))
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break;
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c = old;
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}
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return c;
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}
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#define atomic_dec_return(v) atomic_sub_return(1, (v))
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#define atomic_inc_return(v) atomic_add_return(1, (v))
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/*
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* atomic_sub_and_test - subtract value from variable and test result
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* @i: integer value to subtract
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* @v: pointer of type atomic_t
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*
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* Atomically subtracts @i from @v and returns
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* true if the result is zero, or false for all
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* other cases.
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*/
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#define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
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/*
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* atomic_inc_and_test - increment and test
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* @v: pointer of type atomic_t
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*
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* Atomically increments @v by 1
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* and returns true if the result is zero, or false for all
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* other cases.
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*/
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#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
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/*
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* atomic_dec_and_test - decrement by 1 and test
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* @v: pointer of type atomic_t
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*
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* Atomically decrements @v by 1 and
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* returns true if the result is 0, or false for all other
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* cases.
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*/
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#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
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/*
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* atomic_dec_if_positive - decrement by 1 if old value positive
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* @v: pointer of type atomic_t
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*/
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#define atomic_dec_if_positive(v) atomic_sub_if_positive(1, v)
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/*
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* atomic_inc - increment atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically increments @v by 1.
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*/
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#define atomic_inc(v) atomic_add(1, (v))
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/*
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* atomic_dec - decrement and test
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* @v: pointer of type atomic_t
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*
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* Atomically decrements @v by 1.
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*/
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#define atomic_dec(v) atomic_sub(1, (v))
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/*
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* atomic_add_negative - add and test if negative
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* @v: pointer of type atomic_t
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* @i: integer value to add
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*
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* Atomically adds @i to @v and returns true
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* if the result is negative, or false when
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* result is greater than or equal to zero.
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*/
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#define atomic_add_negative(i, v) (atomic_add_return(i, (v)) < 0)
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#ifdef CONFIG_64BIT
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#define ATOMIC64_INIT(i) { (i) }
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/*
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* atomic64_read - read atomic variable
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* @v: pointer of type atomic64_t
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*
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*/
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#define atomic64_read(v) ACCESS_ONCE((v)->counter)
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/*
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* atomic64_set - set atomic variable
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* @v: pointer of type atomic64_t
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* @i: required value
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*/
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#define atomic64_set(v, i) ((v)->counter = (i))
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#define ATOMIC64_OP(op, c_op, asm_op) \
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static __inline__ void atomic64_##op(long i, atomic64_t * v) \
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{ \
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if (kernel_uses_llsc && R10000_LLSC_WAR) { \
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long temp; \
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\
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__asm__ __volatile__( \
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" .set arch=r4000 \n" \
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"1: lld %0, %1 # atomic64_" #op " \n" \
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" " #asm_op " %0, %2 \n" \
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" scd %0, %1 \n" \
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" beqzl %0, 1b \n" \
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" .set mips0 \n" \
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: "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (v->counter) \
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: "Ir" (i)); \
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} else if (kernel_uses_llsc) { \
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long temp; \
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\
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do { \
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__asm__ __volatile__( \
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" .set "MIPS_ISA_LEVEL" \n" \
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" lld %0, %1 # atomic64_" #op "\n" \
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" " #asm_op " %0, %2 \n" \
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" scd %0, %1 \n" \
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" .set mips0 \n" \
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: "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (v->counter) \
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: "Ir" (i)); \
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} while (unlikely(!temp)); \
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} else { \
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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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}
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#define ATOMIC64_OP_RETURN(op, c_op, asm_op) \
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static __inline__ long atomic64_##op##_return(long i, atomic64_t * v) \
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{ \
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long result; \
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\
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smp_mb__before_llsc(); \
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\
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if (kernel_uses_llsc && R10000_LLSC_WAR) { \
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long temp; \
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\
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__asm__ __volatile__( \
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" .set arch=r4000 \n" \
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"1: lld %1, %2 # atomic64_" #op "_return\n" \
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" " #asm_op " %0, %1, %3 \n" \
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" scd %0, %2 \n" \
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" beqzl %0, 1b \n" \
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" " #asm_op " %0, %1, %3 \n" \
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" .set mips0 \n" \
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: "=&r" (result), "=&r" (temp), \
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"+" GCC_OFF_SMALL_ASM() (v->counter) \
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: "Ir" (i)); \
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} else if (kernel_uses_llsc) { \
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long temp; \
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\
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do { \
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__asm__ __volatile__( \
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" .set "MIPS_ISA_LEVEL" \n" \
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" lld %1, %2 # atomic64_" #op "_return\n" \
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" " #asm_op " %0, %1, %3 \n" \
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" scd %0, %2 \n" \
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" .set mips0 \n" \
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: "=&r" (result), "=&r" (temp), \
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"=" GCC_OFF_SMALL_ASM() (v->counter) \
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: "Ir" (i), GCC_OFF_SMALL_ASM() (v->counter) \
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: "memory"); \
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} while (unlikely(!result)); \
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\
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result = temp; result c_op i; \
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} else { \
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unsigned long flags; \
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\
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raw_local_irq_save(flags); \
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result = v->counter; \
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result c_op i; \
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v->counter = result; \
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raw_local_irq_restore(flags); \
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} \
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\
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smp_llsc_mb(); \
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\
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return result; \
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}
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#define ATOMIC64_OPS(op, c_op, asm_op) \
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ATOMIC64_OP(op, c_op, asm_op) \
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ATOMIC64_OP_RETURN(op, c_op, asm_op)
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ATOMIC64_OPS(add, +=, daddu)
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ATOMIC64_OPS(sub, -=, dsubu)
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ATOMIC64_OP(and, &=, and)
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ATOMIC64_OP(or, |=, or)
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ATOMIC64_OP(xor, ^=, xor)
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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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/*
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* atomic64_sub_if_positive - conditionally subtract integer from atomic
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* variable
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* @i: integer value to subtract
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* @v: pointer of type atomic64_t
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*
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* Atomically test @v and subtract @i if @v is greater or equal than @i.
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* The function returns the old value of @v minus @i.
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*/
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static __inline__ long atomic64_sub_if_positive(long i, atomic64_t * v)
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{
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long result;
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smp_mb__before_llsc();
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if (kernel_uses_llsc && R10000_LLSC_WAR) {
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long temp;
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__asm__ __volatile__(
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" .set arch=r4000 \n"
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"1: lld %1, %2 # atomic64_sub_if_positive\n"
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" dsubu %0, %1, %3 \n"
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" bltz %0, 1f \n"
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" scd %0, %2 \n"
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" .set noreorder \n"
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" beqzl %0, 1b \n"
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" dsubu %0, %1, %3 \n"
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" .set reorder \n"
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"1: \n"
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" .set mips0 \n"
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: "=&r" (result), "=&r" (temp),
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"=" GCC_OFF_SMALL_ASM() (v->counter)
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: "Ir" (i), GCC_OFF_SMALL_ASM() (v->counter)
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: "memory");
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} else if (kernel_uses_llsc) {
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long temp;
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__asm__ __volatile__(
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" .set "MIPS_ISA_LEVEL" \n"
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"1: lld %1, %2 # atomic64_sub_if_positive\n"
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" dsubu %0, %1, %3 \n"
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" bltz %0, 1f \n"
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" scd %0, %2 \n"
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" .set noreorder \n"
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" beqz %0, 1b \n"
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" dsubu %0, %1, %3 \n"
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" .set reorder \n"
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"1: \n"
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" .set mips0 \n"
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: "=&r" (result), "=&r" (temp),
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"+" GCC_OFF_SMALL_ASM() (v->counter)
|
|
: "Ir" (i));
|
|
} else {
|
|
unsigned long flags;
|
|
|
|
raw_local_irq_save(flags);
|
|
result = v->counter;
|
|
result -= i;
|
|
if (result >= 0)
|
|
v->counter = result;
|
|
raw_local_irq_restore(flags);
|
|
}
|
|
|
|
smp_llsc_mb();
|
|
|
|
return result;
|
|
}
|
|
|
|
#define atomic64_cmpxchg(v, o, n) \
|
|
((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
|
|
#define atomic64_xchg(v, new) (xchg(&((v)->counter), (new)))
|
|
|
|
/**
|
|
* atomic64_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, so long as it was not @u.
|
|
* Returns the old value of @v.
|
|
*/
|
|
static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
|
|
{
|
|
long c, old;
|
|
c = atomic64_read(v);
|
|
for (;;) {
|
|
if (unlikely(c == (u)))
|
|
break;
|
|
old = atomic64_cmpxchg((v), c, c + (a));
|
|
if (likely(old == c))
|
|
break;
|
|
c = old;
|
|
}
|
|
return c != (u);
|
|
}
|
|
|
|
#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
|
|
|
|
#define atomic64_dec_return(v) atomic64_sub_return(1, (v))
|
|
#define atomic64_inc_return(v) atomic64_add_return(1, (v))
|
|
|
|
/*
|
|
* atomic64_sub_and_test - subtract value from variable and test result
|
|
* @i: integer value to subtract
|
|
* @v: pointer of type atomic64_t
|
|
*
|
|
* Atomically subtracts @i from @v and returns
|
|
* true if the result is zero, or false for all
|
|
* other cases.
|
|
*/
|
|
#define atomic64_sub_and_test(i, v) (atomic64_sub_return((i), (v)) == 0)
|
|
|
|
/*
|
|
* atomic64_inc_and_test - increment and test
|
|
* @v: pointer of type atomic64_t
|
|
*
|
|
* Atomically increments @v by 1
|
|
* and returns true if the result is zero, or false for all
|
|
* other cases.
|
|
*/
|
|
#define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0)
|
|
|
|
/*
|
|
* atomic64_dec_and_test - decrement by 1 and test
|
|
* @v: pointer of type atomic64_t
|
|
*
|
|
* Atomically decrements @v by 1 and
|
|
* returns true if the result is 0, or false for all other
|
|
* cases.
|
|
*/
|
|
#define atomic64_dec_and_test(v) (atomic64_sub_return(1, (v)) == 0)
|
|
|
|
/*
|
|
* atomic64_dec_if_positive - decrement by 1 if old value positive
|
|
* @v: pointer of type atomic64_t
|
|
*/
|
|
#define atomic64_dec_if_positive(v) atomic64_sub_if_positive(1, v)
|
|
|
|
/*
|
|
* atomic64_inc - increment atomic variable
|
|
* @v: pointer of type atomic64_t
|
|
*
|
|
* Atomically increments @v by 1.
|
|
*/
|
|
#define atomic64_inc(v) atomic64_add(1, (v))
|
|
|
|
/*
|
|
* atomic64_dec - decrement and test
|
|
* @v: pointer of type atomic64_t
|
|
*
|
|
* Atomically decrements @v by 1.
|
|
*/
|
|
#define atomic64_dec(v) atomic64_sub(1, (v))
|
|
|
|
/*
|
|
* atomic64_add_negative - add and test if negative
|
|
* @v: pointer of type atomic64_t
|
|
* @i: integer value to add
|
|
*
|
|
* Atomically adds @i to @v and returns true
|
|
* if the result is negative, or false when
|
|
* result is greater than or equal to zero.
|
|
*/
|
|
#define atomic64_add_negative(i, v) (atomic64_add_return(i, (v)) < 0)
|
|
|
|
#endif /* CONFIG_64BIT */
|
|
|
|
#endif /* _ASM_ATOMIC_H */
|