[linux.git] / include / asm-generic / cmpxchg-local.h

#ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H
#define __ASM_GENERIC_CMPXCHG_LOCAL_H

#include <linux/types.h>
#include <linux/irqflags.h>

extern unsigned long wrong_size_cmpxchg(volatile void *ptr)
	__noreturn;

/*
 * Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
 * long parameter, supporting various types of architectures.
 */
static inline unsigned long __cmpxchg_local_generic(volatile void *ptr,
		unsigned long old, unsigned long new, int size)
{
	unsigned long flags, prev;

	/*
	 * Sanity checking, compile-time.
	 */
	if (size == 8 && sizeof(unsigned long) != 8)
		wrong_size_cmpxchg(ptr);

	raw_local_irq_save(flags);
	switch (size) {
	case 1: prev = *(u8 *)ptr;
		if (prev == old)
			*(u8 *)ptr = (u8)new;
		break;
	case 2: prev = *(u16 *)ptr;
		if (prev == old)
			*(u16 *)ptr = (u16)new;
		break;
	case 4: prev = *(u32 *)ptr;
		if (prev == old)
			*(u32 *)ptr = (u32)new;
		break;
	case 8: prev = *(u64 *)ptr;
		if (prev == old)
			*(u64 *)ptr = (u64)new;
		break;
	default:
		wrong_size_cmpxchg(ptr);
	}
	raw_local_irq_restore(flags);
	return prev;
}

/*
 * Generic version of __cmpxchg64_local. Takes an u64 parameter.
 */
static inline u64 __cmpxchg64_local_generic(volatile void *ptr,
		u64 old, u64 new)
{
	u64 prev;
	unsigned long flags;

	raw_local_irq_save(flags);
	prev = *(u64 *)ptr;
	if (prev == old)
		*(u64 *)ptr = new;
	raw_local_irq_restore(flags);
	return prev;
}

#endif
Commit	Line	Data
068fbad2 MD	1	#ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H
	2	#define __ASM_GENERIC_CMPXCHG_LOCAL_H
	3
	4	#include <linux/types.h>
df9ee292	5	#include <linux/irqflags.h>
068fbad2	6
aa93685a BW	7	extern unsigned long wrong_size_cmpxchg(volatile void *ptr)
aa93685a BW	8	__noreturn;
068fbad2 MD	9
	10	/*
	11	* Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
	12	* long parameter, supporting various types of architectures.
	13	*/
	14	static inline unsigned long __cmpxchg_local_generic(volatile void *ptr,
	15	unsigned long old, unsigned long new, int size)
	16	{
	17	unsigned long flags, prev;
	18
	19	/*
	20	* Sanity checking, compile-time.
	21	*/
	22	if (size == 8 && sizeof(unsigned long) != 8)
	23	wrong_size_cmpxchg(ptr);
	24
5042afe7	25	raw_local_irq_save(flags);
068fbad2 MD	26	switch (size) {
	27	case 1: prev = (u8 )ptr;
	28	if (prev == old)
	29	(u8 )ptr = (u8)new;
	30	break;
	31	case 2: prev = (u16 )ptr;
	32	if (prev == old)
	33	(u16 )ptr = (u16)new;
	34	break;
	35	case 4: prev = (u32 )ptr;
	36	if (prev == old)
	37	(u32 )ptr = (u32)new;
	38	break;
	39	case 8: prev = (u64 )ptr;
	40	if (prev == old)
	41	(u64 )ptr = (u64)new;
	42	break;
	43	default:
	44	wrong_size_cmpxchg(ptr);
	45	}
5042afe7	46	raw_local_irq_restore(flags);
068fbad2 MD	47	return prev;
	48	}
	49
	50	/*
	51	* Generic version of __cmpxchg64_local. Takes an u64 parameter.
	52	*/
	53	static inline u64 __cmpxchg64_local_generic(volatile void *ptr,
	54	u64 old, u64 new)
	55	{
	56	u64 prev;
	57	unsigned long flags;
	58
5042afe7	59	raw_local_irq_save(flags);
068fbad2 MD	60	prev = (u64 )ptr;
	61	if (prev == old)
	62	(u64 )ptr = new;
5042afe7	63	raw_local_irq_restore(flags);
068fbad2 MD	64	return prev;
	65	}
	66
	67	#endif