Add the rt linux 4.1.3-rt3 as base

Import the rt linux 4.1.3-rt3 as OPNFV kvm base.

It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:

commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Sat Jul 25 12:13:34 2015 +0200

    Prepare v4.1.3-rt3

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.

Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>

1 files changed, 127 insertions, 0 deletions

diff --git a/kernel/arch/x86/include/asm/mutex_64.h b/kernel/arch/x86/include/asm/mutex_64.h
new file mode 100644
index 000000000..07537a442
--- /dev/null
+++ b/kernel/arch/x86/include/asm/mutex_64.h
@@ -0,0 +1,127 @@
+/*
+ * Assembly implementation of the mutex fastpath, based on atomic
+ * decrement/increment.
+ *
+ * started by Ingo Molnar:
+ *
+ *  Copyright (C) 2004, 2005, 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ */
+#ifndef _ASM_X86_MUTEX_64_H
+#define _ASM_X86_MUTEX_64_H
+
+/**
+ * __mutex_fastpath_lock - decrement and call function if negative
+ * @v: pointer of type atomic_t
+ * @fail_fn: function to call if the result is negative
+ *
+ * Atomically decrements @v and calls <fail_fn> if the result is negative.
+ */
+#ifdef CC_HAVE_ASM_GOTO
+static inline void __mutex_fastpath_lock(atomic_t *v,
+					 void (*fail_fn)(atomic_t *))
+{
+	asm_volatile_goto(LOCK_PREFIX "   decl %0\n"
+			  "   jns %l[exit]\n"
+			  : : "m" (v->counter)
+			  : "memory", "cc"
+			  : exit);
+	fail_fn(v);
+exit:
+	return;
+}
+#else
+#define __mutex_fastpath_lock(v, fail_fn)			\
+do {								\
+	unsigned long dummy;					\
+								\
+	typecheck(atomic_t *, v);				\
+	typecheck_fn(void (*)(atomic_t *), fail_fn);		\
+								\
+	asm volatile(LOCK_PREFIX "   decl (%%rdi)\n"		\
+		     "   jns 1f		\n"			\
+		     "   call " #fail_fn "\n"			\
+		     "1:"					\
+		     : "=D" (dummy)				\
+		     : "D" (v)					\
+		     : "rax", "rsi", "rdx", "rcx",		\
+		       "r8", "r9", "r10", "r11", "memory");	\
+} while (0)
+#endif
+
+/**
+ *  __mutex_fastpath_lock_retval - try to take the lock by moving the count
+ *                                 from 1 to a 0 value
+ *  @count: pointer of type atomic_t
+ *
+ * Change the count from 1 to a value lower than 1. This function returns 0
+ * if the fastpath succeeds, or -1 otherwise.
+ */
+static inline int __mutex_fastpath_lock_retval(atomic_t *count)
+{
+	if (unlikely(atomic_dec_return(count) < 0))
+		return -1;
+	else
+		return 0;
+}
+
+/**
+ * __mutex_fastpath_unlock - increment and call function if nonpositive
+ * @v: pointer of type atomic_t
+ * @fail_fn: function to call if the result is nonpositive
+ *
+ * Atomically increments @v and calls <fail_fn> if the result is nonpositive.
+ */
+#ifdef CC_HAVE_ASM_GOTO
+static inline void __mutex_fastpath_unlock(atomic_t *v,
+					   void (*fail_fn)(atomic_t *))
+{
+	asm_volatile_goto(LOCK_PREFIX "   incl %0\n"
+			  "   jg %l[exit]\n"
+			  : : "m" (v->counter)
+			  : "memory", "cc"
+			  : exit);
+	fail_fn(v);
+exit:
+	return;
+}
+#else
+#define __mutex_fastpath_unlock(v, fail_fn)			\
+do {								\
+	unsigned long dummy;					\
+								\
+	typecheck(atomic_t *, v);				\
+	typecheck_fn(void (*)(atomic_t *), fail_fn);		\
+								\
+	asm volatile(LOCK_PREFIX "   incl (%%rdi)\n"		\
+		     "   jg 1f\n"				\
+		     "   call " #fail_fn "\n"			\
+		     "1:"					\
+		     : "=D" (dummy)				\
+		     : "D" (v)					\
+		     : "rax", "rsi", "rdx", "rcx",		\
+		       "r8", "r9", "r10", "r11", "memory");	\
+} while (0)
+#endif
+
+#define __mutex_slowpath_needs_to_unlock()	1
+
+/**
+ * __mutex_fastpath_trylock - try to acquire the mutex, without waiting
+ *
+ *  @count: pointer of type atomic_t
+ *  @fail_fn: fallback function
+ *
+ * Change the count from 1 to 0 and return 1 (success), or return 0 (failure)
+ * if it wasn't 1 originally. [the fallback function is never used on
+ * x86_64, because all x86_64 CPUs have a CMPXCHG instruction.]
+ */
+static inline int __mutex_fastpath_trylock(atomic_t *count,
+					   int (*fail_fn)(atomic_t *))
+{
+	if (likely(atomic_cmpxchg(count, 1, 0) == 1))
+		return 1;
+	else
+		return 0;
+}
+
+#endif /* _ASM_X86_MUTEX_64_H */