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, 110 insertions, 0 deletions

diff --git a/kernel/arch/x86/include/asm/mutex_32.h b/kernel/arch/x86/include/asm/mutex_32.h
new file mode 100644
index 000000000..85e6cda45
--- /dev/null
+++ b/kernel/arch/x86/include/asm/mutex_32.h
@@ -0,0 +1,110 @@
+/*
+ * 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_32_H
+#define _ASM_X86_MUTEX_32_H
+
+#include <asm/alternative.h>
+
+/**
+ *  __mutex_fastpath_lock - try to take the lock by moving the count
+ *                          from 1 to a 0 value
+ *  @count: pointer of type atomic_t
+ *  @fn: function to call if the original value was not 1
+ *
+ * Change the count from 1 to a value lower than 1, and call <fn> if it
+ * wasn't 1 originally. This function MUST leave the value lower than 1
+ * even when the "1" assertion wasn't true.
+ */
+#define __mutex_fastpath_lock(count, fail_fn)			\
+do {								\
+	unsigned int dummy;					\
+								\
+	typecheck(atomic_t *, count);				\
+	typecheck_fn(void (*)(atomic_t *), fail_fn);		\
+								\
+	asm volatile(LOCK_PREFIX "   decl (%%eax)\n"		\
+		     "   jns 1f	\n"				\
+		     "   call " #fail_fn "\n"			\
+		     "1:\n"					\
+		     : "=a" (dummy)				\
+		     : "a" (count)				\
+		     : "memory", "ecx", "edx");			\
+} while (0)
+
+
+/**
+ *  __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 - try to promote the mutex from 0 to 1
+ *  @count: pointer of type atomic_t
+ *  @fail_fn: function to call if the original value was not 0
+ *
+ * try to promote the mutex from 0 to 1. if it wasn't 0, call <fail_fn>.
+ * In the failure case, this function is allowed to either set the value
+ * to 1, or to set it to a value lower than 1.
+ *
+ * If the implementation sets it to a value of lower than 1, the
+ * __mutex_slowpath_needs_to_unlock() macro needs to return 1, it needs
+ * to return 0 otherwise.
+ */
+#define __mutex_fastpath_unlock(count, fail_fn)			\
+do {								\
+	unsigned int dummy;					\
+								\
+	typecheck(atomic_t *, count);				\
+	typecheck_fn(void (*)(atomic_t *), fail_fn);		\
+								\
+	asm volatile(LOCK_PREFIX "   incl (%%eax)\n"		\
+		     "   jg	1f\n"				\
+		     "   call " #fail_fn "\n"			\
+		     "1:\n"					\
+		     : "=a" (dummy)				\
+		     : "a" (count)				\
+		     : "memory", "ecx", "edx");			\
+} while (0)
+
+#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 a value lower than 1, and return 0 (failure)
+ * if it wasn't 1 originally, or return 1 (success) otherwise. This function
+ * MUST leave the value lower than 1 even when the "1" assertion wasn't true.
+ * Additionally, if the value was < 0 originally, this function must not leave
+ * it to 0 on failure.
+ */
+static inline int __mutex_fastpath_trylock(atomic_t *count,
+					   int (*fail_fn)(atomic_t *))
+{
+	/* cmpxchg because it never induces a false contention state. */
+	if (likely(atomic_cmpxchg(count, 1, 0) == 1))
+		return 1;
+
+	return 0;
+}
+
+#endif /* _ASM_X86_MUTEX_32_H */