1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H
 3#define __ASM_GENERIC_CMPXCHG_LOCAL_H
 4
 5#include <linux/types.h>
 6#include <linux/irqflags.h>
 7
 8extern unsigned long wrong_size_cmpxchg(volatile void *ptr)
 9	__noreturn;
10
11/*
12 * Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
13 * long parameter, supporting various types of architectures.
14 */
15static inline unsigned long __generic_cmpxchg_local(volatile void *ptr,
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
26	raw_local_irq_save(flags);
27	switch (size) {
28	case 1: prev = *(u8 *)ptr;
29		if (prev == (old & 0xffu))
30			*(u8 *)ptr = (new & 0xffu);
31		break;
32	case 2: prev = *(u16 *)ptr;
33		if (prev == (old & 0xffffu))
34			*(u16 *)ptr = (new & 0xffffu);
35		break;
36	case 4: prev = *(u32 *)ptr;
37		if (prev == (old & 0xffffffffu))
38			*(u32 *)ptr = (new & 0xffffffffu);
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	}
47	raw_local_irq_restore(flags);
48	return prev;
49}
50
51/*
52 * Generic version of __cmpxchg64_local. Takes an u64 parameter.
53 */
54static inline u64 __generic_cmpxchg64_local(volatile void *ptr,
55		u64 old, u64 new)
56{
57	u64 prev;
58	unsigned long flags;
59
60	raw_local_irq_save(flags);
61	prev = *(u64 *)ptr;
62	if (prev == old)
63		*(u64 *)ptr = new;
64	raw_local_irq_restore(flags);
65	return prev;
66}
67
68#endif

 1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H
 3#define __ASM_GENERIC_CMPXCHG_LOCAL_H
 4
 5#include <linux/types.h>
 6#include <linux/irqflags.h>
 7
 8extern unsigned long wrong_size_cmpxchg(volatile void *ptr)
 9	__noreturn;
10
11/*
12 * Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
13 * long parameter, supporting various types of architectures.
14 */
15static inline unsigned long __generic_cmpxchg_local(volatile void *ptr,
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
26	raw_local_irq_save(flags);
27	switch (size) {
28	case 1: prev = *(u8 *)ptr;
29		if (prev == (old & 0xffu))
30			*(u8 *)ptr = (new & 0xffu);
31		break;
32	case 2: prev = *(u16 *)ptr;
33		if (prev == (old & 0xffffu))
34			*(u16 *)ptr = (new & 0xffffu);
35		break;
36	case 4: prev = *(u32 *)ptr;
37		if (prev == (old & 0xffffffffu))
38			*(u32 *)ptr = (new & 0xffffffffu);
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	}
47	raw_local_irq_restore(flags);
48	return prev;
49}
50
51/*
52 * Generic version of __cmpxchg64_local. Takes an u64 parameter.
53 */
54static inline u64 __generic_cmpxchg64_local(volatile void *ptr,
55		u64 old, u64 new)
56{
57	u64 prev;
58	unsigned long flags;
59
60	raw_local_irq_save(flags);
61	prev = *(u64 *)ptr;
62	if (prev == old)
63		*(u64 *)ptr = new;
64	raw_local_irq_restore(flags);
65	return prev;
66}
67
68#endif