1#ifndef __ASM_GENERIC_CMPXCHG_H
 2#define __ASM_GENERIC_CMPXCHG_H
 3
 4/*
 5 * Generic cmpxchg
 6 *
 7 * Uses the local cmpxchg. Does not support SMP.
 8 */
 9#ifdef CONFIG_SMP
10#error "Cannot use generic cmpxchg on SMP"
11#endif
12
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
13/*
14 * Atomic compare and exchange.
15 *
16 * Do not define __HAVE_ARCH_CMPXCHG because we want to use it to check whether
17 * a cmpxchg primitive faster than repeated local irq save/restore exists.
18 */
 
 
 
 
 
 
 
 
 
 
 
 
19#define cmpxchg(ptr, o, n)	cmpxchg_local((ptr), (o), (n))
20#define cmpxchg64(ptr, o, n)	cmpxchg64_local((ptr), (o), (n))
21
22#endif

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