[mirror_ubuntu-bionic-kernel.git] / include / asm-generic / cmpxchg.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Generic UP xchg and cmpxchg using interrupt disablement.  Does not
 * support SMP.
 */

#ifndef __ASM_GENERIC_CMPXCHG_H
#define __ASM_GENERIC_CMPXCHG_H

#ifdef CONFIG_SMP
#error "Cannot use generic cmpxchg on SMP"
#endif

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

#ifndef xchg

/*
 * This function doesn't exist, so you'll get a linker error if
 * something tries to do an invalidly-sized xchg().
 */
extern void __xchg_called_with_bad_pointer(void);

static inline
unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
{
	unsigned long ret, flags;

	switch (size) {
	case 1:
#ifdef __xchg_u8
		return __xchg_u8(x, ptr);
#else
		local_irq_save(flags);
		ret = *(volatile u8 *)ptr;
		*(volatile u8 *)ptr = x;
		local_irq_restore(flags);
		return ret;
#endif /* __xchg_u8 */

	case 2:
#ifdef __xchg_u16
		return __xchg_u16(x, ptr);
#else
		local_irq_save(flags);
		ret = *(volatile u16 *)ptr;
		*(volatile u16 *)ptr = x;
		local_irq_restore(flags);
		return ret;
#endif /* __xchg_u16 */

	case 4:
#ifdef __xchg_u32
		return __xchg_u32(x, ptr);
#else
		local_irq_save(flags);
		ret = *(volatile u32 *)ptr;
		*(volatile u32 *)ptr = x;
		local_irq_restore(flags);
		return ret;
#endif /* __xchg_u32 */

#ifdef CONFIG_64BIT
	case 8:
#ifdef __xchg_u64
		return __xchg_u64(x, ptr);
#else
		local_irq_save(flags);
		ret = *(volatile u64 *)ptr;
		*(volatile u64 *)ptr = x;
		local_irq_restore(flags);
		return ret;
#endif /* __xchg_u64 */
#endif /* CONFIG_64BIT */

	default:
		__xchg_called_with_bad_pointer();
		return x;
	}
}

#define xchg(ptr, x) ({							\
	((__typeof__(*(ptr)))						\
		__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))));	\
})

#endif /* xchg */

/*
 * Atomic compare and exchange.
 */
#include <asm-generic/cmpxchg-local.h>

#ifndef cmpxchg_local
#define cmpxchg_local(ptr, o, n) ({					       \
	((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
			(unsigned long)(n), sizeof(*(ptr))));		       \
})
#endif

#ifndef cmpxchg64_local
#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
#endif

#define cmpxchg(ptr, o, n)	cmpxchg_local((ptr), (o), (n))
#define cmpxchg64(ptr, o, n)	cmpxchg64_local((ptr), (o), (n))

#endif /* __ASM_GENERIC_CMPXCHG_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
b4816afa DH	2	/*
	3	* Generic UP xchg and cmpxchg using interrupt disablement. Does not
	4	* support SMP.
	5	*/
	6
068fbad2 MD	7	#ifndef __ASM_GENERIC_CMPXCHG_H
	8	#define __ASM_GENERIC_CMPXCHG_H
	9
068fbad2 MD	10	#ifdef CONFIG_SMP
	11	#error "Cannot use generic cmpxchg on SMP"
	12	#endif
	13
80da6a4f	14	#include <linux/types.h>
b4816afa DH	15	#include <linux/irqflags.h>
	16
	17	#ifndef xchg
	18
	19	/*
	20	* This function doesn't exist, so you'll get a linker error if
	21	* something tries to do an invalidly-sized xchg().
	22	*/
	23	extern void __xchg_called_with_bad_pointer(void);
	24
	25	static inline
	26	unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
	27	{
	28	unsigned long ret, flags;
	29
	30	switch (size) {
	31	case 1:
	32	#ifdef __xchg_u8
	33	return __xchg_u8(x, ptr);
	34	#else
	35	local_irq_save(flags);
	36	ret = (volatile u8 )ptr;
	37	(volatile u8 )ptr = x;
	38	local_irq_restore(flags);
	39	return ret;
	40	#endif /* __xchg_u8 */
	41
	42	case 2:
	43	#ifdef __xchg_u16
	44	return __xchg_u16(x, ptr);
	45	#else
	46	local_irq_save(flags);
	47	ret = (volatile u16 )ptr;
	48	(volatile u16 )ptr = x;
	49	local_irq_restore(flags);
	50	return ret;
	51	#endif /* __xchg_u16 */
	52
	53	case 4:
	54	#ifdef __xchg_u32
	55	return __xchg_u32(x, ptr);
	56	#else
	57	local_irq_save(flags);
	58	ret = (volatile u32 )ptr;
	59	(volatile u32 )ptr = x;
	60	local_irq_restore(flags);
	61	return ret;
	62	#endif /* __xchg_u32 */
	63
	64	#ifdef CONFIG_64BIT
	65	case 8:
	66	#ifdef __xchg_u64
	67	return __xchg_u64(x, ptr);
	68	#else
	69	local_irq_save(flags);
	70	ret = (volatile u64 )ptr;
	71	(volatile u64 )ptr = x;
	72	local_irq_restore(flags);
	73	return ret;
	74	#endif /* __xchg_u64 */
	75	#endif /* CONFIG_64BIT */
	76
	77	default:
	78	__xchg_called_with_bad_pointer();
79	return x;
80	}
81	}
82
d975440b MV	83	#define xchg(ptr, x) ({ \
	84	((__typeof__(*(ptr))) \
	85	__xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \
	86	})
b4816afa DH	87
b4816afa DH	88	#endif /* xchg */
34484277	89
068fbad2 MD	90	/*
068fbad2 MD	91	* Atomic compare and exchange.
068fbad2	92	*/
b4816afa DH	93	#include <asm-generic/cmpxchg-local.h>
b4816afa DH	94
00c30e06	95	#ifndef cmpxchg_local
d975440b	96	#define cmpxchg_local(ptr, o, n) ({ \
00c30e06	97	((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
d975440b MV	98	(unsigned long)(n), sizeof(*(ptr)))); \
d975440b MV	99	})
00c30e06 JB	100	#endif
	101
	102	#ifndef cmpxchg64_local
	103	#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
	104	#endif
	105
068fbad2 MD	106	#define cmpxchg(ptr, o, n) cmpxchg_local((ptr), (o), (n))
	107	#define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n))
	108
b4816afa	109	#endif /* __ASM_GENERIC_CMPXCHG_H */