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/mips/include/asm/switch_to.h b/kernel/arch/mips/include/asm/switch_to.h
new file mode 100644
index 000000000..7163cd7fd
--- /dev/null
+++ b/kernel/arch/mips/include/asm/switch_to.h
@@ -0,0 +1,127 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1994, 95, 96, 97, 98, 99, 2003, 06 by Ralf Baechle
+ * Copyright (C) 1996 by Paul M. Antoine
+ * Copyright (C) 1999 Silicon Graphics
+ * Kevin D. Kissell, kevink@mips.org and Carsten Langgaard, carstenl@mips.com
+ * Copyright (C) 2000 MIPS Technologies, Inc.
+ */
+#ifndef _ASM_SWITCH_TO_H
+#define _ASM_SWITCH_TO_H
+
+#include <asm/cpu-features.h>
+#include <asm/watch.h>
+#include <asm/dsp.h>
+#include <asm/cop2.h>
+#include <asm/msa.h>
+
+struct task_struct;
+
+enum {
+	FP_SAVE_NONE	= 0,
+	FP_SAVE_VECTOR	= -1,
+	FP_SAVE_SCALAR	= 1,
+};
+
+/**
+ * resume - resume execution of a task
+ * @prev:	The task previously executed.
+ * @next:	The task to begin executing.
+ * @next_ti:	task_thread_info(next).
+ * @fp_save:	Which, if any, FP context to save for prev.
+ *
+ * This function is used whilst scheduling to save the context of prev & load
+ * the context of next. Returns prev.
+ */
+extern asmlinkage struct task_struct *resume(struct task_struct *prev,
+		struct task_struct *next, struct thread_info *next_ti,
+		s32 fp_save);
+
+extern unsigned int ll_bit;
+extern struct task_struct *ll_task;
+
+#ifdef CONFIG_MIPS_MT_FPAFF
+
+/*
+ * Handle the scheduler resume end of FPU affinity management.	We do this
+ * inline to try to keep the overhead down. If we have been forced to run on
+ * a "CPU" with an FPU because of a previous high level of FP computation,
+ * but did not actually use the FPU during the most recent time-slice (CU1
+ * isn't set), we undo the restriction on cpus_allowed.
+ *
+ * We're not calling set_cpus_allowed() here, because we have no need to
+ * force prompt migration - we're already switching the current CPU to a
+ * different thread.
+ */
+
+#define __mips_mt_fpaff_switch_to(prev)					\
+do {									\
+	struct thread_info *__prev_ti = task_thread_info(prev);		\
+									\
+	if (cpu_has_fpu &&						\
+	    test_ti_thread_flag(__prev_ti, TIF_FPUBOUND) &&		\
+	    (!(KSTK_STATUS(prev) & ST0_CU1))) {				\
+		clear_ti_thread_flag(__prev_ti, TIF_FPUBOUND);		\
+		prev->cpus_allowed = prev->thread.user_cpus_allowed;	\
+	}								\
+	next->thread.emulated_fp = 0;					\
+} while(0)
+
+#else
+#define __mips_mt_fpaff_switch_to(prev) do { (void) (prev); } while (0)
+#endif
+
+#define __clear_software_ll_bit()					\
+do {	if (cpu_has_rw_llb) {						\
+		write_c0_lladdr(0);					\
+	} else {							\
+		if (!__builtin_constant_p(cpu_has_llsc) || !cpu_has_llsc)\
+			ll_bit = 0;					\
+	}								\
+} while (0)
+
+#define switch_to(prev, next, last)					\
+do {									\
+	u32 __c0_stat;							\
+	s32 __fpsave = FP_SAVE_NONE;					\
+	__mips_mt_fpaff_switch_to(prev);				\
+	if (cpu_has_dsp)						\
+		__save_dsp(prev);					\
+	if (cop2_present && (KSTK_STATUS(prev) & ST0_CU2)) {		\
+		if (cop2_lazy_restore)					\
+			KSTK_STATUS(prev) &= ~ST0_CU2;			\
+		__c0_stat = read_c0_status();				\
+		write_c0_status(__c0_stat | ST0_CU2);			\
+		cop2_save(prev);					\
+		write_c0_status(__c0_stat & ~ST0_CU2);			\
+	}								\
+	__clear_software_ll_bit();					\
+	if (test_and_clear_tsk_thread_flag(prev, TIF_USEDFPU))		\
+		__fpsave = FP_SAVE_SCALAR;				\
+	if (test_and_clear_tsk_thread_flag(prev, TIF_USEDMSA))		\
+		__fpsave = FP_SAVE_VECTOR;				\
+	(last) = resume(prev, next, task_thread_info(next), __fpsave);	\
+} while (0)
+
+#define finish_arch_switch(prev)					\
+do {									\
+	u32 __c0_stat;							\
+	if (cop2_present && !cop2_lazy_restore &&			\
+			(KSTK_STATUS(current) & ST0_CU2)) {		\
+		__c0_stat = read_c0_status();				\
+		write_c0_status(__c0_stat | ST0_CU2);			\
+		cop2_restore(current);					\
+		write_c0_status(__c0_stat & ~ST0_CU2);			\
+	}								\
+	if (cpu_has_dsp)						\
+		__restore_dsp(current);					\
+	if (cpu_has_userlocal)						\
+		write_c0_userlocal(current_thread_info()->tp_value);	\
+	__restore_watch();						\
+	disable_msa();							\
+} while (0)
+
+#endif /* _ASM_SWITCH_TO_H */