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diff --git a/arch/mn10300/include/asm/system.h b/arch/mn10300/include/asm/system.h
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+/* MN10300 System definitions
+ *
+ * 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_SYSTEM_H
+#define _ASM_SYSTEM_H
+
+#include <asm/cpu-regs.h>
+
+#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
+
+#include <linux/kernel.h>
+
+struct task_struct;
+struct thread_struct;
+
+extern asmlinkage
+struct task_struct *__switch_to(struct thread_struct *prev,
+ struct thread_struct *next,
+ struct task_struct *prev_task);
+
+/* context switching is now performed out-of-line in switch_to.S */
+#define switch_to(prev, next, last) \
+do { \
+ current->thread.wchan = (u_long) __builtin_return_address(0); \
+ (last) = __switch_to(&(prev)->thread, &(next)->thread, (prev)); \
+ mb(); \
+ current->thread.wchan = 0; \
+} 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.
+ *
+ * For now, "wmb()" doesn't actually do anything, as all
+ * Intel CPU's follow what Intel calls a *Processor Order*,
+ * in which all writes are seen in the program order even
+ * outside the CPU.
+ *
+ * I expect future Intel CPU's to have a weaker ordering,
+ * but I'd also expect them to finally get their act together
+ * and add some real memory barriers if so.
+ *
+ * Some non intel clones support out of order store. wmb() ceases to be a
+ * nop for these.
+ */
+
+#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)
+
+/*****************************************************************************/
+/*
+ * interrupt control
+ * - "disabled": run in IM1/2
+ * - level 0 - GDB stub
+ * - level 1 - virtual serial DMA (if present)
+ * - level 5 - normal interrupt priority
+ * - level 6 - timer interrupt
+ * - "enabled": run in IM7
+ */
+#ifdef CONFIG_MN10300_TTYSM
+#define MN10300_CLI_LEVEL EPSW_IM_2
+#else
+#define MN10300_CLI_LEVEL EPSW_IM_1
+#endif
+
+#define local_save_flags(x) \
+do { \
+ typecheck(unsigned long, x); \
+ asm volatile( \
+ " mov epsw,%0 \n" \
+ : "=d"(x) \
+ ); \
+} while (0)
+
+#define local_irq_disable() \
+do { \
+ asm volatile( \
+ " and %0,epsw \n" \
+ " or %1,epsw \n" \
+ " nop \n" \
+ " nop \n" \
+ " nop \n" \
+ : \
+ : "i"(~EPSW_IM), "i"(EPSW_IE | MN10300_CLI_LEVEL) \
+ ); \
+} while (0)
+
+#define local_irq_save(x) \
+do { \
+ local_save_flags(x); \
+ local_irq_disable(); \
+} while (0)
+
+/*
+ * we make sure local_irq_enable() doesn't cause priority inversion
+ */
+#ifndef __ASSEMBLY__
+
+extern unsigned long __mn10300_irq_enabled_epsw;
+
+#endif
+
+#define local_irq_enable() \
+do { \
+ unsigned long tmp; \
+ \
+ asm volatile( \
+ " mov epsw,%0 \n" \
+ " and %1,%0 \n" \
+ " or %2,%0 \n" \
+ " mov %0,epsw \n" \
+ : "=&d"(tmp) \
+ : "i"(~EPSW_IM), "r"(__mn10300_irq_enabled_epsw) \
+ ); \
+} while (0)
+
+#define local_irq_restore(x) \
+do { \
+ typecheck(unsigned long, x); \
+ asm volatile( \
+ " mov %0,epsw \n" \
+ " nop \n" \
+ " nop \n" \
+ " nop \n" \
+ : \
+ : "d"(x) \
+ : "memory", "cc" \
+ ); \
+} while (0)
+
+#define irqs_disabled() \
+({ \
+ unsigned long flags; \
+ local_save_flags(flags); \
+ (flags & EPSW_IM) <= MN10300_CLI_LEVEL; \
+})
+
+/* hook to save power by halting the CPU
+ * - called from the idle loop
+ * - must reenable interrupts (which takes three instruction cycles to complete)
+ */
+#define safe_halt() \
+do { \
+ asm volatile(" or %0,epsw \n" \
+ " nop \n" \
+ " nop \n" \
+ " bset %2,(%1) \n" \
+ : \
+ : "i"(EPSW_IE|EPSW_IM), "n"(&CPUM), "i"(CPUM_SLEEP)\
+ : "cc" \
+ ); \
+} while (0)
+
+#define STI or EPSW_IE|EPSW_IM,epsw
+#define CLI and ~EPSW_IM,epsw; or EPSW_IE|MN10300_CLI_LEVEL,epsw; nop; nop; nop
+
+/*****************************************************************************/
+/*
+ * MN10300 doesn't actually have an exchange instruction
+ */
+#ifndef __ASSEMBLY__
+
+struct __xchg_dummy { unsigned long a[100]; };
+#define __xg(x) ((struct __xchg_dummy *)(x))
+
+static inline
+unsigned long __xchg(volatile unsigned long *m, unsigned long val)
+{
+ unsigned long retval;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ retval = *m;
+ *m = val;
+ local_irq_restore(flags);
+ return retval;
+}
+
+#define xchg(ptr, v) \
+ ((__typeof__(*(ptr))) __xchg((unsigned long *)(ptr), \
+ (unsigned long)(v)))
+
+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_SYSTEM_H */