File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/tile/include/asm/stack.h b/arch/tile/include/asm/stack.h
new file mode 100644
index 0000000..c3cb426
--- /dev/null
+++ b/arch/tile/include/asm/stack.h
@@ -0,0 +1,71 @@
+/*
+ * 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_STACK_H
+#define _ASM_TILE_STACK_H
+
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <asm/backtrace.h>
+#include <asm/page.h>
+#include <hv/hypervisor.h>
+
+/* Everything we need to keep track of a backtrace iteration */
+struct KBacktraceIterator {
+	BacktraceIterator it;
+	struct task_struct *task;     /* task we are backtracing */
+	int end;		      /* iteration complete. */
+	int new_context;              /* new context is starting */
+	int profile;                  /* profiling, so stop on async intrpt */
+	int verbose;		      /* printk extra info (don't want to
+				       * do this for profiling) */
+	int is_current;               /* backtracing current task */
+};
+
+/* Iteration methods for kernel backtraces */
+
+/*
+ * Initialize a KBacktraceIterator from a task_struct, and optionally from
+ * a set of registers.  If the registers are omitted, the process is
+ * assumed to be descheduled, and registers are read from the process's
+ * thread_struct and stack.  "verbose" means to printk some additional
+ * information about fault handlers as we pass them on the stack.
+ */
+extern void KBacktraceIterator_init(struct KBacktraceIterator *kbt,
+				    struct task_struct *, struct pt_regs *);
+
+/* Initialize iterator based on current stack. */
+extern void KBacktraceIterator_init_current(struct KBacktraceIterator *kbt);
+
+/* Helper method for above. */
+extern void _KBacktraceIterator_init_current(struct KBacktraceIterator *kbt,
+				ulong pc, ulong lr, ulong sp, ulong r52);
+
+/* No more frames? */
+extern int KBacktraceIterator_end(struct KBacktraceIterator *kbt);
+
+/* Advance to the next frame. */
+extern void KBacktraceIterator_next(struct KBacktraceIterator *kbt);
+
+/* Dump just the contents of the pt_regs structure. */
+extern void tile_show_regs(struct pt_regs *);
+
+/*
+ * Dump stack given complete register info. Use only from the
+ * architecture-specific code; show_stack()
+ * and dump_stack() are architecture-independent entry points.
+ */
+extern void tile_show_stack(struct KBacktraceIterator *);
+
+#endif /* _ASM_TILE_STACK_H */