linux-stable/include/asm-generic/atomic.h

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Generic C implementation of atomic counter operations. Usable on
* UP systems only. Do not include in machine independent code.
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#ifndef __ASM_GENERIC_ATOMIC_H
#define __ASM_GENERIC_ATOMIC_H
#include <asm/cmpxchg.h>
#include <asm/barrier.h>
/*
* atomic_$op() - $op integer to atomic variable
* @i: integer value to $op
* @v: pointer to the atomic variable
*
* Atomically $ops @i to @v. Does not strictly guarantee a memory-barrier, use
* smp_mb__{before,after}_atomic().
*/
/*
* atomic_$op_return() - $op interer to atomic variable and returns the result
* @i: integer value to $op
* @v: pointer to the atomic variable
*
* Atomically $ops @i to @v. Does imply a full memory barrier.
*/
#ifdef CONFIG_SMP
/* we can build all atomic primitives from cmpxchg */
#define ATOMIC_OP(op, c_op) \
static inline void atomic_##op(int i, atomic_t *v) \
{ \
int c, old; \
\
c = v->counter; \
while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \
c = old; \
}
#define ATOMIC_OP_RETURN(op, c_op) \
static inline int atomic_##op##_return(int i, atomic_t *v) \
{ \
int c, old; \
\
c = v->counter; \
while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \
c = old; \
\
return c c_op i; \
}
#define ATOMIC_FETCH_OP(op, c_op) \
static inline int atomic_fetch_##op(int i, atomic_t *v) \
{ \
int c, old; \
\
c = v->counter; \
while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \
c = old; \
\
return c; \
}
#else
#include <linux/irqflags.h>
#define ATOMIC_OP(op, c_op) \
static inline void atomic_##op(int i, atomic_t *v) \
{ \
unsigned long flags; \
\
raw_local_irq_save(flags); \
v->counter = v->counter c_op i; \
raw_local_irq_restore(flags); \
}
#define ATOMIC_OP_RETURN(op, c_op) \
static inline int atomic_##op##_return(int i, atomic_t *v) \
{ \
unsigned long flags; \
int ret; \
\
raw_local_irq_save(flags); \
ret = (v->counter = v->counter c_op i); \
raw_local_irq_restore(flags); \
\
return ret; \
}
#define ATOMIC_FETCH_OP(op, c_op) \
static inline int atomic_fetch_##op(int i, atomic_t *v) \
{ \
unsigned long flags; \
int ret; \
\
raw_local_irq_save(flags); \
ret = v->counter; \
v->counter = v->counter c_op i; \
raw_local_irq_restore(flags); \
\
return ret; \
}
#endif /* CONFIG_SMP */
#ifndef atomic_add_return
ATOMIC_OP_RETURN(add, +)
#endif
#ifndef atomic_sub_return
ATOMIC_OP_RETURN(sub, -)
#endif
#ifndef atomic_fetch_add
ATOMIC_FETCH_OP(add, +)
#endif
#ifndef atomic_fetch_sub
ATOMIC_FETCH_OP(sub, -)
#endif
#ifndef atomic_fetch_and
ATOMIC_FETCH_OP(and, &)
#endif
#ifndef atomic_fetch_or
ATOMIC_FETCH_OP(or, |)
#endif
#ifndef atomic_fetch_xor
ATOMIC_FETCH_OP(xor, ^)
#endif
#ifndef atomic_and
ATOMIC_OP(and, &)
#endif
#ifndef atomic_or
ATOMIC_OP(or, |)
#endif
#ifndef atomic_xor
ATOMIC_OP(xor, ^)
#endif
#undef ATOMIC_FETCH_OP
#undef ATOMIC_OP_RETURN
#undef ATOMIC_OP
/*
* Atomic operations that C can't guarantee us. Useful for
* resource counting etc..
*/
/**
* atomic_read - read atomic variable
* @v: pointer of type atomic_t
*
* Atomically reads the value of @v.
*/
#ifndef atomic_read
#define atomic_read(v) READ_ONCE((v)->counter)
#endif
/**
* atomic_set - set atomic variable
* @v: pointer of type atomic_t
* @i: required value
*
* Atomically sets the value of @v to @i.
*/
#define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
Fix IRQ flag handling naming Fix the IRQ flag handling naming. In linux/irqflags.h under one configuration, it maps: local_irq_enable() -> raw_local_irq_enable() local_irq_disable() -> raw_local_irq_disable() local_irq_save() -> raw_local_irq_save() ... and under the other configuration, it maps: raw_local_irq_enable() -> local_irq_enable() raw_local_irq_disable() -> local_irq_disable() raw_local_irq_save() -> local_irq_save() ... This is quite confusing. There should be one set of names expected of the arch, and this should be wrapped to give another set of names that are expected by users of this facility. Change this to have the arch provide: flags = arch_local_save_flags() flags = arch_local_irq_save() arch_local_irq_restore(flags) arch_local_irq_disable() arch_local_irq_enable() arch_irqs_disabled_flags(flags) arch_irqs_disabled() arch_safe_halt() Then linux/irqflags.h wraps these to provide: raw_local_save_flags(flags) raw_local_irq_save(flags) raw_local_irq_restore(flags) raw_local_irq_disable() raw_local_irq_enable() raw_irqs_disabled_flags(flags) raw_irqs_disabled() raw_safe_halt() with type checking on the flags 'arguments', and then wraps those to provide: local_save_flags(flags) local_irq_save(flags) local_irq_restore(flags) local_irq_disable() local_irq_enable() irqs_disabled_flags(flags) irqs_disabled() safe_halt() with tracing included if enabled. The arch functions can now all be inline functions rather than some of them having to be macros. Signed-off-by: David Howells <dhowells@redhat.com> [X86, FRV, MN10300] Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> [Tile] Signed-off-by: Michal Simek <monstr@monstr.eu> [Microblaze] Tested-by: Catalin Marinas <catalin.marinas@arm.com> [ARM] Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> [AVR] Acked-by: Tony Luck <tony.luck@intel.com> [IA-64] Acked-by: Hirokazu Takata <takata@linux-m32r.org> [M32R] Acked-by: Greg Ungerer <gerg@uclinux.org> [M68K/M68KNOMMU] Acked-by: Ralf Baechle <ralf@linux-mips.org> [MIPS] Acked-by: Kyle McMartin <kyle@mcmartin.ca> [PA-RISC] Acked-by: Paul Mackerras <paulus@samba.org> [PowerPC] Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [S390] Acked-by: Chen Liqin <liqin.chen@sunplusct.com> [Score] Acked-by: Matt Fleming <matt@console-pimps.org> [SH] Acked-by: David S. Miller <davem@davemloft.net> [Sparc] Acked-by: Chris Zankel <chris@zankel.net> [Xtensa] Reviewed-by: Richard Henderson <rth@twiddle.net> [Alpha] Reviewed-by: Yoshinori Sato <ysato@users.sourceforge.jp> [H8300] Cc: starvik@axis.com [CRIS] Cc: jesper.nilsson@axis.com [CRIS] Cc: linux-cris-kernel@axis.com
2010-10-07 13:08:55 +00:00
#include <linux/irqflags.h>
static inline void atomic_add(int i, atomic_t *v)
{
atomic_add_return(i, v);
}
static inline void atomic_sub(int i, atomic_t *v)
{
atomic_sub_return(i, v);
}
#define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v)))
#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
#endif /* __ASM_GENERIC_ATOMIC_H */