132 lines
3.3 KiB
C
132 lines
3.3 KiB
C
/* MN10300 System definitions
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#ifndef _ASM_SYSTEM_H
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#define _ASM_SYSTEM_H
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#include <asm/cpu-regs.h>
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#ifdef __KERNEL__
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#ifndef __ASSEMBLY__
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#include <linux/kernel.h>
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#include <linux/irqflags.h>
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struct task_struct;
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struct thread_struct;
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extern asmlinkage
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struct task_struct *__switch_to(struct thread_struct *prev,
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struct thread_struct *next,
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struct task_struct *prev_task);
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/* context switching is now performed out-of-line in switch_to.S */
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#define switch_to(prev, next, last) \
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do { \
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current->thread.wchan = (u_long) __builtin_return_address(0); \
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(last) = __switch_to(&(prev)->thread, &(next)->thread, (prev)); \
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mb(); \
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current->thread.wchan = 0; \
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} while (0)
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#define arch_align_stack(x) (x)
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#define nop() asm volatile ("nop")
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#endif /* !__ASSEMBLY__ */
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/*
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* Force strict CPU ordering.
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* And yes, this is required on UP too when we're talking
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* to devices.
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*
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* For now, "wmb()" doesn't actually do anything, as all
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* Intel CPU's follow what Intel calls a *Processor Order*,
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* in which all writes are seen in the program order even
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* outside the CPU.
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*
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* I expect future Intel CPU's to have a weaker ordering,
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* but I'd also expect them to finally get their act together
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* and add some real memory barriers if so.
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*
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* Some non intel clones support out of order store. wmb() ceases to be a
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* nop for these.
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*/
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#define mb() asm volatile ("": : :"memory")
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#define rmb() mb()
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#define wmb() asm volatile ("": : :"memory")
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#ifdef CONFIG_SMP
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#define smp_mb() mb()
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#define smp_rmb() rmb()
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#define smp_wmb() wmb()
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#else
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#define smp_mb() barrier()
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#define smp_rmb() barrier()
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#define smp_wmb() barrier()
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#endif
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#define set_mb(var, value) do { var = value; mb(); } while (0)
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#define set_wmb(var, value) do { var = value; wmb(); } while (0)
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#define read_barrier_depends() do {} while (0)
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#define smp_read_barrier_depends() do {} while (0)
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/*****************************************************************************/
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/*
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* MN10300 doesn't actually have an exchange instruction
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*/
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#ifndef __ASSEMBLY__
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struct __xchg_dummy { unsigned long a[100]; };
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#define __xg(x) ((struct __xchg_dummy *)(x))
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static inline
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unsigned long __xchg(volatile unsigned long *m, unsigned long val)
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{
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unsigned long retval;
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unsigned long flags;
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local_irq_save(flags);
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retval = *m;
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*m = val;
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local_irq_restore(flags);
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return retval;
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}
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#define xchg(ptr, v) \
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((__typeof__(*(ptr))) __xchg((unsigned long *)(ptr), \
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(unsigned long)(v)))
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static inline unsigned long __cmpxchg(volatile unsigned long *m,
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unsigned long old, unsigned long new)
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{
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unsigned long retval;
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unsigned long flags;
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local_irq_save(flags);
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retval = *m;
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if (retval == old)
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*m = new;
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local_irq_restore(flags);
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return retval;
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}
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#define cmpxchg(ptr, o, n) \
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((__typeof__(*(ptr))) __cmpxchg((unsigned long *)(ptr), \
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(unsigned long)(o), \
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(unsigned long)(n)))
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#endif /* !__ASSEMBLY__ */
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#endif /* __KERNEL__ */
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#endif /* _ASM_SYSTEM_H */
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