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

/* SPDX-License-Identifier: GPL-2.0 */
#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 __generic_cmpxchg_local(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 & 0xffu))
			*(u8 *)ptr = (new & 0xffu);
		break;
	case 2: prev = *(u16 *)ptr;
		if (prev == (old & 0xffffu))
			*(u16 *)ptr = (new & 0xffffu);
		break;
	case 4: prev = *(u32 *)ptr;
		if (prev == (old & 0xffffffffffu))
			*(u32 *)ptr = (new & 0xffffffffu);
		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 __generic_cmpxchg64_local(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
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
068fbad2 MD	2	#ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H
	3	#define __ASM_GENERIC_CMPXCHG_LOCAL_H
	4
	5	#include <linux/types.h>
df9ee292	6	#include <linux/irqflags.h>
068fbad2	7
aa93685a BW	8	extern unsigned long wrong_size_cmpxchg(volatile void *ptr)
aa93685a BW	9	__noreturn;
068fbad2 MD	10
	11	/*
	12	* Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
	13	* long parameter, supporting various types of architectures.
	14	*/
6988631b	15	static inline unsigned long __generic_cmpxchg_local(volatile void *ptr,
068fbad2 MD	16	unsigned long old, unsigned long new, int size)
	17	{
	18	unsigned long flags, prev;
	19
	20	/*
	21	* Sanity checking, compile-time.
	22	*/
	23	if (size == 8 && sizeof(unsigned long) != 8)
	24	wrong_size_cmpxchg(ptr);
	25
5042afe7	26	raw_local_irq_save(flags);
068fbad2 MD	27	switch (size) {
068fbad2 MD	28	case 1: prev = (u8 )ptr;
656e9007 AB	29	if (prev == (old & 0xffu))
656e9007 AB	30	(u8 )ptr = (new & 0xffu);
068fbad2 MD	31	break;
068fbad2 MD	32	case 2: prev = (u16 )ptr;
656e9007 AB	33	if (prev == (old & 0xffffu))
656e9007 AB	34	(u16 )ptr = (new & 0xffffu);
068fbad2 MD	35	break;
068fbad2 MD	36	case 4: prev = (u32 )ptr;
656e9007 AB	37	if (prev == (old & 0xffffffffffu))
656e9007 AB	38	(u32 )ptr = (new & 0xffffffffu);
068fbad2 MD	39	break;
	40	case 8: prev = (u64 )ptr;
	41	if (prev == old)
	42	(u64 )ptr = (u64)new;
	43	break;
	44	default:
	45	wrong_size_cmpxchg(ptr);
	46	}
5042afe7	47	raw_local_irq_restore(flags);
068fbad2 MD	48	return prev;
	49	}
	50
	51	/*
	52	* Generic version of __cmpxchg64_local. Takes an u64 parameter.
	53	*/
6988631b	54	static inline u64 __generic_cmpxchg64_local(volatile void *ptr,
068fbad2 MD	55	u64 old, u64 new)
	56	{
	57	u64 prev;
	58	unsigned long flags;
	59
5042afe7	60	raw_local_irq_save(flags);
068fbad2 MD	61	prev = (u64 )ptr;
	62	if (prev == old)
	63	(u64 )ptr = new;
5042afe7	64	raw_local_irq_restore(flags);
068fbad2 MD	65	return prev;
	66	}
	67
	68	#endif