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, 88 insertions, 0 deletions

diff --git a/kernel/arch/arm/mm/copypage-v4wt.c b/kernel/arch/arm/mm/copypage-v4wt.c
new file mode 100644
index 000000000..b85c5da2e
--- /dev/null
+++ b/kernel/arch/arm/mm/copypage-v4wt.c
@@ -0,0 +1,88 @@
+/*
+ *  linux/arch/arm/mm/copypage-v4wt.S
+ *
+ *  Copyright (C) 1995-1999 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ *  This is for CPUs with a writethrough cache and 'flush ID cache' is
+ *  the only supported cache operation.
+ */
+#include <linux/init.h>
+#include <linux/highmem.h>
+
+/*
+ * ARMv4 optimised copy_user_highpage
+ *
+ * Since we have writethrough caches, we don't have to worry about
+ * dirty data in the cache.  However, we do have to ensure that
+ * subsequent reads are up to date.
+ */
+static void __naked
+v4wt_copy_user_page(void *kto, const void *kfrom)
+{
+	asm("\
+	stmfd	sp!, {r4, lr}			@ 2\n\
+	mov	r2, %2				@ 1\n\
+	ldmia	r1!, {r3, r4, ip, lr}		@ 4\n\
+1:	stmia	r0!, {r3, r4, ip, lr}		@ 4\n\
+	ldmia	r1!, {r3, r4, ip, lr}		@ 4+1\n\
+	stmia	r0!, {r3, r4, ip, lr}		@ 4\n\
+	ldmia	r1!, {r3, r4, ip, lr}		@ 4\n\
+	stmia	r0!, {r3, r4, ip, lr}		@ 4\n\
+	ldmia	r1!, {r3, r4, ip, lr}		@ 4\n\
+	subs	r2, r2, #1			@ 1\n\
+	stmia	r0!, {r3, r4, ip, lr}		@ 4\n\
+	ldmneia	r1!, {r3, r4, ip, lr}		@ 4\n\
+	bne	1b				@ 1\n\
+	mcr	p15, 0, r2, c7, c7, 0		@ flush ID cache\n\
+	ldmfd	sp!, {r4, pc}			@ 3"
+	:
+	: "r" (kto), "r" (kfrom), "I" (PAGE_SIZE / 64));
+}
+
+void v4wt_copy_user_highpage(struct page *to, struct page *from,
+	unsigned long vaddr, struct vm_area_struct *vma)
+{
+	void *kto, *kfrom;
+
+	kto = kmap_atomic(to);
+	kfrom = kmap_atomic(from);
+	v4wt_copy_user_page(kto, kfrom);
+	kunmap_atomic(kfrom);
+	kunmap_atomic(kto);
+}
+
+/*
+ * ARMv4 optimised clear_user_page
+ *
+ * Same story as above.
+ */
+void v4wt_clear_user_highpage(struct page *page, unsigned long vaddr)
+{
+	void *ptr, *kaddr = kmap_atomic(page);
+	asm volatile("\
+	mov	r1, %2				@ 1\n\
+	mov	r2, #0				@ 1\n\
+	mov	r3, #0				@ 1\n\
+	mov	ip, #0				@ 1\n\
+	mov	lr, #0				@ 1\n\
+1:	stmia	%0!, {r2, r3, ip, lr}		@ 4\n\
+	stmia	%0!, {r2, r3, ip, lr}		@ 4\n\
+	stmia	%0!, {r2, r3, ip, lr}		@ 4\n\
+	stmia	%0!, {r2, r3, ip, lr}		@ 4\n\
+	subs	r1, r1, #1			@ 1\n\
+	bne	1b				@ 1\n\
+	mcr	p15, 0, r2, c7, c7, 0		@ flush ID cache"
+	: "=r" (ptr)
+	: "0" (kaddr), "I" (PAGE_SIZE / 64)
+	: "r1", "r2", "r3", "ip", "lr");
+	kunmap_atomic(kaddr);
+}
+
+struct cpu_user_fns v4wt_user_fns __initdata = {
+	.cpu_clear_user_highpage = v4wt_clear_user_highpage,
+	.cpu_copy_user_highpage	= v4wt_copy_user_highpage,
+};