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/* Generic system definitions, based on MN10300 definitions.
*
* It should be possible to use these on really simple architectures,
* but it serves more as a starting point for new ports.
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#ifndef __ASM_GENERIC_SYSTEM_H
#define __ASM_GENERIC_SYSTEM_H
#ifdef __KERNEL__
#ifndef __ASSEMBLY__
#include <linux/types.h>
#include <linux/irqflags.h>
#include <asm/cmpxchg-local.h>
struct task_struct;
/* context switching is now performed out-of-line in switch_to.S */
extern struct task_struct *__switch_to(struct task_struct *,
struct task_struct *);
#define switch_to(prev, next, last) \
do { \
((last) = __switch_to((prev), (next))); \
} while (0)
#define arch_align_stack(x) (x)
#define nop() asm volatile ("nop")
#endif /* !__ASSEMBLY__ */
/*
* Force strict CPU ordering.
* And yes, this is required on UP too when we're talking
* to devices.
*
* This implementation only contains a compiler barrier.
*/
#define mb() asm volatile ("": : :"memory")
#define rmb() mb()
#define wmb() asm volatile ("": : :"memory")
#ifdef CONFIG_SMP
#define smp_mb() mb()
#define smp_rmb() rmb()
#define smp_wmb() wmb()
#else
#define smp_mb() barrier()
#define smp_rmb() barrier()
#define smp_wmb() barrier()
#endif
#define set_mb(var, value) do { var = value; mb(); } while (0)
#define set_wmb(var, value) do { var = value; wmb(); } while (0)
#define read_barrier_depends() do {} while (0)
#define smp_read_barrier_depends() do {} while (0)
/*
* we make sure local_irq_enable() doesn't cause priority inversion
*/
#ifndef __ASSEMBLY__
/* This function doesn't exist, so you'll get a linker error
* if something tries to do an invalid 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))))
static inline unsigned long __cmpxchg(volatile unsigned long *m,
unsigned long old, unsigned long new)
{
unsigned long retval;
unsigned long flags;
local_irq_save(flags);
retval = *m;
if (retval == old)
*m = new;
local_irq_restore(flags);
return retval;
}
#define cmpxchg(ptr, o, n) \
((__typeof__(*(ptr))) __cmpxchg((unsigned long *)(ptr), \
(unsigned long)(o), \
(unsigned long)(n)))
#endif /* !__ASSEMBLY__ */
#endif /* __KERNEL__ */
#endif /* __ASM_GENERIC_SYSTEM_H */
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