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, 146 insertions, 0 deletions

diff --git a/kernel/arch/powerpc/mm/mmu_context_hash64.c b/kernel/arch/powerpc/mm/mmu_context_hash64.c
new file mode 100644
index 000000000..178876aef
--- /dev/null
+++ b/kernel/arch/powerpc/mm/mmu_context_hash64.c
@@ -0,0 +1,146 @@
+/*
+ *  MMU context allocation for 64-bit kernels.
+ *
+ *  Copyright (C) 2004 Anton Blanchard, IBM Corp. <anton@samba.org>
+ *
+ *  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; either version
+ *  2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/spinlock.h>
+#include <linux/idr.h>
+#include <linux/export.h>
+#include <linux/gfp.h>
+#include <linux/slab.h>
+
+#include <asm/mmu_context.h>
+#include <asm/pgalloc.h>
+
+#include "icswx.h"
+
+static DEFINE_SPINLOCK(mmu_context_lock);
+static DEFINE_IDA(mmu_context_ida);
+
+int __init_new_context(void)
+{
+	int index;
+	int err;
+
+again:
+	if (!ida_pre_get(&mmu_context_ida, GFP_KERNEL))
+		return -ENOMEM;
+
+	spin_lock(&mmu_context_lock);
+	err = ida_get_new_above(&mmu_context_ida, 1, &index);
+	spin_unlock(&mmu_context_lock);
+
+	if (err == -EAGAIN)
+		goto again;
+	else if (err)
+		return err;
+
+	if (index > MAX_USER_CONTEXT) {
+		spin_lock(&mmu_context_lock);
+		ida_remove(&mmu_context_ida, index);
+		spin_unlock(&mmu_context_lock);
+		return -ENOMEM;
+	}
+
+	return index;
+}
+EXPORT_SYMBOL_GPL(__init_new_context);
+
+int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+	int index;
+
+	index = __init_new_context();
+	if (index < 0)
+		return index;
+
+	/* The old code would re-promote on fork, we don't do that
+	 * when using slices as it could cause problem promoting slices
+	 * that have been forced down to 4K
+	 */
+	if (slice_mm_new_context(mm))
+		slice_set_user_psize(mm, mmu_virtual_psize);
+	subpage_prot_init_new_context(mm);
+	mm->context.id = index;
+#ifdef CONFIG_PPC_ICSWX
+	mm->context.cop_lockp = kmalloc(sizeof(spinlock_t), GFP_KERNEL);
+	if (!mm->context.cop_lockp) {
+		__destroy_context(index);
+		subpage_prot_free(mm);
+		mm->context.id = MMU_NO_CONTEXT;
+		return -ENOMEM;
+	}
+	spin_lock_init(mm->context.cop_lockp);
+#endif /* CONFIG_PPC_ICSWX */
+
+#ifdef CONFIG_PPC_64K_PAGES
+	mm->context.pte_frag = NULL;
+#endif
+	return 0;
+}
+
+void __destroy_context(int context_id)
+{
+	spin_lock(&mmu_context_lock);
+	ida_remove(&mmu_context_ida, context_id);
+	spin_unlock(&mmu_context_lock);
+}
+EXPORT_SYMBOL_GPL(__destroy_context);
+
+#ifdef CONFIG_PPC_64K_PAGES
+static void destroy_pagetable_page(struct mm_struct *mm)
+{
+	int count;
+	void *pte_frag;
+	struct page *page;
+
+	pte_frag = mm->context.pte_frag;
+	if (!pte_frag)
+		return;
+
+	page = virt_to_page(pte_frag);
+	/* drop all the pending references */
+	count = ((unsigned long)pte_frag & ~PAGE_MASK) >> PTE_FRAG_SIZE_SHIFT;
+	/* We allow PTE_FRAG_NR fragments from a PTE page */
+	count = atomic_sub_return(PTE_FRAG_NR - count, &page->_count);
+	if (!count) {
+		pgtable_page_dtor(page);
+		free_hot_cold_page(page, 0);
+	}
+}
+
+#else
+static inline void destroy_pagetable_page(struct mm_struct *mm)
+{
+	return;
+}
+#endif
+
+
+void destroy_context(struct mm_struct *mm)
+{
+
+#ifdef CONFIG_PPC_ICSWX
+	drop_cop(mm->context.acop, mm);
+	kfree(mm->context.cop_lockp);
+	mm->context.cop_lockp = NULL;
+#endif /* CONFIG_PPC_ICSWX */
+
+	destroy_pagetable_page(mm);
+	__destroy_context(mm->context.id);
+	subpage_prot_free(mm);
+	mm->context.id = MMU_NO_CONTEXT;
+}