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diff --git a/arch/tile/include/asm/system.h b/arch/tile/include/asm/system.h
new file mode 100644
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+++ b/arch/tile/include/asm/system.h
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+/*
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful, but
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ */
+
+#ifndef _ASM_TILE_SYSTEM_H
+#define _ASM_TILE_SYSTEM_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+#include <linux/irqflags.h>
+
+/* NOTE: we can't include <linux/ptrace.h> due to #include dependencies. */
+#include <asm/ptrace.h>
+
+#include <arch/chip.h>
+#include <arch/sim_def.h>
+#include <arch/spr_def.h>
+
+/*
+ * read_barrier_depends - Flush all pending reads that subsequents reads
+ * depend on.
+ *
+ * No data-dependent reads from memory-like regions are ever reordered
+ * over this barrier.  All reads preceding this primitive are guaranteed
+ * to access memory (but not necessarily other CPUs' caches) before any
+ * reads following this primitive that depend on the data return by
+ * any of the preceding reads.  This primitive is much lighter weight than
+ * rmb() on most CPUs, and is never heavier weight than is
+ * rmb().
+ *
+ * These ordering constraints are respected by both the local CPU
+ * and the compiler.
+ *
+ * Ordering is not guaranteed by anything other than these primitives,
+ * not even by data dependencies.  See the documentation for
+ * memory_barrier() for examples and URLs to more information.
+ *
+ * For example, the following code would force ordering (the initial
+ * value of "a" is zero, "b" is one, and "p" is "&a"):
+ *
+ * <programlisting>
+ *      CPU 0                           CPU 1
+ *
+ *      b = 2;
+ *      memory_barrier();
+ *      p = &b;                         q = p;
+ *                                      read_barrier_depends();
+ *                                      d = *q;
+ * </programlisting>
+ *
+ * because the read of "*q" depends on the read of "p" and these
+ * two reads are separated by a read_barrier_depends().  However,
+ * the following code, with the same initial values for "a" and "b":
+ *
+ * <programlisting>
+ *      CPU 0                           CPU 1
+ *
+ *      a = 2;
+ *      memory_barrier();
+ *      b = 3;                          y = b;
+ *                                      read_barrier_depends();
+ *                                      x = a;
+ * </programlisting>
+ *
+ * does not enforce ordering, since there is no data dependency between
+ * the read of "a" and the read of "b".  Therefore, on some CPUs, such
+ * as Alpha, "y" could be set to 3 and "x" to 0.  Use rmb()
+ * in cases like this where there are no data dependencies.
+ */
+
+#define read_barrier_depends()  do { } while (0)
+
+#define __sync()        __insn_mf()
+
+#if CHIP_HAS_SPLIT_CYCLE()
+#define get_cycles_low() __insn_mfspr(SPR_CYCLE_LOW)
+#else
+#define get_cycles_low() __insn_mfspr(SPR_CYCLE)   /* just get all 64 bits */
+#endif
+
+/* Fence to guarantee visibility of stores to incoherent memory. */
+static inline void
+mb_incoherent(void)
+{
+        __insn_mf();
+
+#if !CHIP_HAS_MF_WAITS_FOR_VICTIMS()
+        {
+                int __mb_incoherent(void);
+#if CHIP_HAS_TILE_WRITE_PENDING()
+                const unsigned long WRITE_TIMEOUT_CYCLES = 400;
+                unsigned long start = get_cycles_low();
+                do {
+                        if (__insn_mfspr(SPR_TILE_WRITE_PENDING) == 0)
+                                return;
+                } while ((get_cycles_low() - start) < WRITE_TIMEOUT_CYCLES);
+#endif /* CHIP_HAS_TILE_WRITE_PENDING() */
+                (void) __mb_incoherent();
+        }
+#endif /* CHIP_HAS_MF_WAITS_FOR_VICTIMS() */
+}
+
+#define fast_wmb()      __sync()
+#define fast_rmb()      __sync()
+#define fast_mb()       __sync()
+#define fast_iob()      mb_incoherent()
+
+#define wmb()           fast_wmb()
+#define rmb()           fast_rmb()
+#define mb()            fast_mb()
+#define iob()           fast_iob()
+
+#ifdef CONFIG_SMP
+#define smp_mb()        mb()
+#define smp_rmb()       rmb()
+#define smp_wmb()       wmb()
+#define smp_read_barrier_depends()      read_barrier_depends()
+#else
+#define smp_mb()        barrier()
+#define smp_rmb()       barrier()
+#define smp_wmb()       barrier()
+#define smp_read_barrier_depends()      do { } while (0)
+#endif
+
+#define set_mb(var, value) \
+        do { var = value; mb(); } while (0)
+
+#include <linux/irqflags.h>
+
+/*
+ * Pause the DMA engine and static network before task switching.
+ */
+#define prepare_arch_switch(next) _prepare_arch_switch(next)
+void _prepare_arch_switch(struct task_struct *next);
+
+
+/*
+ * switch_to(n) should switch tasks to task nr n, first
+ * checking that n isn't the current task, in which case it does nothing.
+ * The number of callee-saved registers saved on the kernel stack
+ * is defined here for use in copy_thread() and must agree with __switch_to().
+ */
+#endif /* !__ASSEMBLY__ */
+#define CALLEE_SAVED_FIRST_REG 30
+#define CALLEE_SAVED_REGS_COUNT 24   /* r30 to r52, plus an empty to align */
+#ifndef __ASSEMBLY__
+struct task_struct;
+#define switch_to(prev, next, last) ((last) = _switch_to((prev), (next)))
+extern struct task_struct *_switch_to(struct task_struct *prev,
+                                      struct task_struct *next);
+
+/*
+ * On SMP systems, when the scheduler does migration-cost autodetection,
+ * it needs a way to flush as much of the CPU's caches as possible:
+ *
+ * TODO: fill this in!
+ */
+static inline void sched_cacheflush(void)
+{
+}
+
+#define arch_align_stack(x) (x)
+
+/*
+ * Is the kernel doing fixups of unaligned accesses?  If <0, no kernel
+ * intervention occurs and SIGBUS is delivered with no data address
+ * info.  If 0, the kernel single-steps the instruction to discover
+ * the data address to provide with the SIGBUS.  If 1, the kernel does
+ * a fixup.
+ */
+extern int unaligned_fixup;
+
+/* Is the kernel printing on each unaligned fixup? */
+extern int unaligned_printk;
+
+/* Number of unaligned fixups performed */
+extern unsigned int unaligned_fixup_count;
+
+/* User-level DMA management functions */
+void grant_dma_mpls(void);
+void restrict_dma_mpls(void);
+
+
+/* Invoke the simulator "syscall" mechanism (see arch/tile/kernel/entry.S). */
+extern int _sim_syscall(int syscall_num, ...);
+#define sim_syscall(syscall_num, ...) \
+        _sim_syscall(SIM_CONTROL_SYSCALL + \
+                ((syscall_num) << _SIM_CONTROL_OPERATOR_BITS), \
+                ## __VA_ARGS__)
+
+/*
+ * Kernel threads can check to see if they need to migrate their
+ * stack whenever they return from a context switch; for user
+ * threads, we defer until they are returning to user-space.
+ */
+#define finish_arch_switch(prev) do {                                     \
+        if (unlikely((prev)->state == TASK_DEAD))                         \
+                __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_EXIT |       \
+                        ((prev)->pid << _SIM_CONTROL_OPERATOR_BITS));     \
+        __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_SWITCH |             \
+                (current->pid << _SIM_CONTROL_OPERATOR_BITS));            \
+        if (current->mm == NULL && !kstack_hash &&                        \
+            current_thread_info()->homecache_cpu != smp_processor_id())   \
+                homecache_migrate_kthread();                              \
+} while (0)
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* _ASM_TILE_SYSTEM_H */