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, 278 insertions, 0 deletions

diff --git a/kernel/arch/xtensa/mm/tlb.c b/kernel/arch/xtensa/mm/tlb.c
new file mode 100644
index 000000000..5ece856c5
--- /dev/null
+++ b/kernel/arch/xtensa/mm/tlb.c
@@ -0,0 +1,278 @@
+/*
+ * arch/xtensa/mm/tlb.c
+ *
+ * Logic that manipulates the Xtensa MMU.  Derived from MIPS.
+ *
+ * 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) 2001 - 2003 Tensilica Inc.
+ *
+ * Joe Taylor
+ * Chris Zankel	<chris@zankel.net>
+ * Marc Gauthier
+ */
+
+#include <linux/mm.h>
+#include <asm/processor.h>
+#include <asm/mmu_context.h>
+#include <asm/tlbflush.h>
+#include <asm/cacheflush.h>
+
+
+static inline void __flush_itlb_all (void)
+{
+	int w, i;
+
+	for (w = 0; w < ITLB_ARF_WAYS; w++) {
+		for (i = 0; i < (1 << XCHAL_ITLB_ARF_ENTRIES_LOG2); i++) {
+			int e = w + (i << PAGE_SHIFT);
+			invalidate_itlb_entry_no_isync(e);
+		}
+	}
+	asm volatile ("isync\n");
+}
+
+static inline void __flush_dtlb_all (void)
+{
+	int w, i;
+
+	for (w = 0; w < DTLB_ARF_WAYS; w++) {
+		for (i = 0; i < (1 << XCHAL_DTLB_ARF_ENTRIES_LOG2); i++) {
+			int e = w + (i << PAGE_SHIFT);
+			invalidate_dtlb_entry_no_isync(e);
+		}
+	}
+	asm volatile ("isync\n");
+}
+
+
+void local_flush_tlb_all(void)
+{
+	__flush_itlb_all();
+	__flush_dtlb_all();
+}
+
+/* If mm is current, we simply assign the current task a new ASID, thus,
+ * invalidating all previous tlb entries. If mm is someone else's user mapping,
+ * wie invalidate the context, thus, when that user mapping is swapped in,
+ * a new context will be assigned to it.
+ */
+
+void local_flush_tlb_mm(struct mm_struct *mm)
+{
+	int cpu = smp_processor_id();
+
+	if (mm == current->active_mm) {
+		unsigned long flags;
+		local_irq_save(flags);
+		mm->context.asid[cpu] = NO_CONTEXT;
+		activate_context(mm, cpu);
+		local_irq_restore(flags);
+	} else {
+		mm->context.asid[cpu] = NO_CONTEXT;
+		mm->context.cpu = -1;
+	}
+}
+
+
+#define _ITLB_ENTRIES (ITLB_ARF_WAYS << XCHAL_ITLB_ARF_ENTRIES_LOG2)
+#define _DTLB_ENTRIES (DTLB_ARF_WAYS << XCHAL_DTLB_ARF_ENTRIES_LOG2)
+#if _ITLB_ENTRIES > _DTLB_ENTRIES
+# define _TLB_ENTRIES _ITLB_ENTRIES
+#else
+# define _TLB_ENTRIES _DTLB_ENTRIES
+#endif
+
+void local_flush_tlb_range(struct vm_area_struct *vma,
+		unsigned long start, unsigned long end)
+{
+	int cpu = smp_processor_id();
+	struct mm_struct *mm = vma->vm_mm;
+	unsigned long flags;
+
+	if (mm->context.asid[cpu] == NO_CONTEXT)
+		return;
+
+#if 0
+	printk("[tlbrange<%02lx,%08lx,%08lx>]\n",
+			(unsigned long)mm->context.asid[cpu], start, end);
+#endif
+	local_irq_save(flags);
+
+	if (end-start + (PAGE_SIZE-1) <= _TLB_ENTRIES << PAGE_SHIFT) {
+		int oldpid = get_rasid_register();
+
+		set_rasid_register(ASID_INSERT(mm->context.asid[cpu]));
+		start &= PAGE_MASK;
+		if (vma->vm_flags & VM_EXEC)
+			while(start < end) {
+				invalidate_itlb_mapping(start);
+				invalidate_dtlb_mapping(start);
+				start += PAGE_SIZE;
+			}
+		else
+			while(start < end) {
+				invalidate_dtlb_mapping(start);
+				start += PAGE_SIZE;
+			}
+
+		set_rasid_register(oldpid);
+	} else {
+		local_flush_tlb_mm(mm);
+	}
+	local_irq_restore(flags);
+}
+
+void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
+{
+	int cpu = smp_processor_id();
+	struct mm_struct* mm = vma->vm_mm;
+	unsigned long flags;
+	int oldpid;
+
+	if (mm->context.asid[cpu] == NO_CONTEXT)
+		return;
+
+	local_irq_save(flags);
+
+	oldpid = get_rasid_register();
+	set_rasid_register(ASID_INSERT(mm->context.asid[cpu]));
+
+	if (vma->vm_flags & VM_EXEC)
+		invalidate_itlb_mapping(page);
+	invalidate_dtlb_mapping(page);
+
+	set_rasid_register(oldpid);
+
+	local_irq_restore(flags);
+}
+
+void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
+{
+	if (end > start && start >= TASK_SIZE && end <= PAGE_OFFSET &&
+	    end - start < _TLB_ENTRIES << PAGE_SHIFT) {
+		start &= PAGE_MASK;
+		while (start < end) {
+			invalidate_itlb_mapping(start);
+			invalidate_dtlb_mapping(start);
+			start += PAGE_SIZE;
+		}
+	} else {
+		local_flush_tlb_all();
+	}
+}
+
+#ifdef CONFIG_DEBUG_TLB_SANITY
+
+static unsigned get_pte_for_vaddr(unsigned vaddr)
+{
+	struct task_struct *task = get_current();
+	struct mm_struct *mm = task->mm;
+	pgd_t *pgd;
+	pmd_t *pmd;
+	pte_t *pte;
+
+	if (!mm)
+		mm = task->active_mm;
+	pgd = pgd_offset(mm, vaddr);
+	if (pgd_none_or_clear_bad(pgd))
+		return 0;
+	pmd = pmd_offset(pgd, vaddr);
+	if (pmd_none_or_clear_bad(pmd))
+		return 0;
+	pte = pte_offset_map(pmd, vaddr);
+	if (!pte)
+		return 0;
+	return pte_val(*pte);
+}
+
+enum {
+	TLB_SUSPICIOUS	= 1,
+	TLB_INSANE	= 2,
+};
+
+static void tlb_insane(void)
+{
+	BUG_ON(1);
+}
+
+static void tlb_suspicious(void)
+{
+	WARN_ON(1);
+}
+
+/*
+ * Check that TLB entries with kernel ASID (1) have kernel VMA (>= TASK_SIZE),
+ * and TLB entries with user ASID (>=4) have VMA < TASK_SIZE.
+ *
+ * Check that valid TLB entries either have the same PA as the PTE, or PTE is
+ * marked as non-present. Non-present PTE and the page with non-zero refcount
+ * and zero mapcount is normal for batched TLB flush operation. Zero refcount
+ * means that the page was freed prematurely. Non-zero mapcount is unusual,
+ * but does not necessary means an error, thus marked as suspicious.
+ */
+static int check_tlb_entry(unsigned w, unsigned e, bool dtlb)
+{
+	unsigned tlbidx = w | (e << PAGE_SHIFT);
+	unsigned r0 = dtlb ?
+		read_dtlb_virtual(tlbidx) : read_itlb_virtual(tlbidx);
+	unsigned vpn = (r0 & PAGE_MASK) | (e << PAGE_SHIFT);
+	unsigned pte = get_pte_for_vaddr(vpn);
+	unsigned mm_asid = (get_rasid_register() >> 8) & ASID_MASK;
+	unsigned tlb_asid = r0 & ASID_MASK;
+	bool kernel = tlb_asid == 1;
+	int rc = 0;
+
+	if (tlb_asid > 0 && ((vpn < TASK_SIZE) == kernel)) {
+		pr_err("%cTLB: way: %u, entry: %u, VPN %08x in %s PTE\n",
+				dtlb ? 'D' : 'I', w, e, vpn,
+				kernel ? "kernel" : "user");
+		rc |= TLB_INSANE;
+	}
+
+	if (tlb_asid == mm_asid) {
+		unsigned r1 = dtlb ? read_dtlb_translation(tlbidx) :
+			read_itlb_translation(tlbidx);
+		if ((pte ^ r1) & PAGE_MASK) {
+			pr_err("%cTLB: way: %u, entry: %u, mapping: %08x->%08x, PTE: %08x\n",
+					dtlb ? 'D' : 'I', w, e, r0, r1, pte);
+			if (pte == 0 || !pte_present(__pte(pte))) {
+				struct page *p = pfn_to_page(r1 >> PAGE_SHIFT);
+				pr_err("page refcount: %d, mapcount: %d\n",
+						page_count(p),
+						page_mapcount(p));
+				if (!page_count(p))
+					rc |= TLB_INSANE;
+				else if (page_mapped(p))
+					rc |= TLB_SUSPICIOUS;
+			} else {
+				rc |= TLB_INSANE;
+			}
+		}
+	}
+	return rc;
+}
+
+void check_tlb_sanity(void)
+{
+	unsigned long flags;
+	unsigned w, e;
+	int bug = 0;
+
+	local_irq_save(flags);
+	for (w = 0; w < DTLB_ARF_WAYS; ++w)
+		for (e = 0; e < (1 << XCHAL_DTLB_ARF_ENTRIES_LOG2); ++e)
+			bug |= check_tlb_entry(w, e, true);
+	for (w = 0; w < ITLB_ARF_WAYS; ++w)
+		for (e = 0; e < (1 << XCHAL_ITLB_ARF_ENTRIES_LOG2); ++e)
+			bug |= check_tlb_entry(w, e, false);
+	if (bug & TLB_INSANE)
+		tlb_insane();
+	if (bug & TLB_SUSPICIOUS)
+		tlb_suspicious();
+	local_irq_restore(flags);
+}
+
+#endif /* CONFIG_DEBUG_TLB_SANITY */