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, 342 insertions, 0 deletions

diff --git a/kernel/arch/mips/mm/fault.c b/kernel/arch/mips/mm/fault.c
new file mode 100644
index 000000000..36c0f26fa
--- /dev/null
+++ b/kernel/arch/mips/mm/fault.c
@@ -0,0 +1,342 @@
+/*
+ * 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) 1995 - 2000 by Ralf Baechle
+ */
+#include <linux/context_tracking.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/ratelimit.h>
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/module.h>
+#include <linux/kprobes.h>
+#include <linux/perf_event.h>
+#include <linux/uaccess.h>
+
+#include <asm/branch.h>
+#include <asm/mmu_context.h>
+#include <asm/ptrace.h>
+#include <asm/highmem.h>		/* For VMALLOC_END */
+#include <linux/kdebug.h>
+
+int show_unhandled_signals = 1;
+
+/*
+ * This routine handles page faults.  It determines the address,
+ * and the problem, and then passes it off to one of the appropriate
+ * routines.
+ */
+static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write,
+	unsigned long address)
+{
+	struct vm_area_struct * vma = NULL;
+	struct task_struct *tsk = current;
+	struct mm_struct *mm = tsk->mm;
+	const int field = sizeof(unsigned long) * 2;
+	siginfo_t info;
+	int fault;
+	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+
+	static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
+
+#if 0
+	printk("Cpu%d[%s:%d:%0*lx:%ld:%0*lx]\n", raw_smp_processor_id(),
+	       current->comm, current->pid, field, address, write,
+	       field, regs->cp0_epc);
+#endif
+
+#ifdef CONFIG_KPROBES
+	/*
+	 * This is to notify the fault handler of the kprobes.	The
+	 * exception code is redundant as it is also carried in REGS,
+	 * but we pass it anyhow.
+	 */
+	if (notify_die(DIE_PAGE_FAULT, "page fault", regs, -1,
+		       (regs->cp0_cause >> 2) & 0x1f, SIGSEGV) == NOTIFY_STOP)
+		return;
+#endif
+
+	info.si_code = SEGV_MAPERR;
+
+	/*
+	 * We fault-in kernel-space virtual memory on-demand. The
+	 * 'reference' page table is init_mm.pgd.
+	 *
+	 * NOTE! We MUST NOT take any locks for this case. We may
+	 * be in an interrupt or a critical region, and should
+	 * only copy the information from the master page table,
+	 * nothing more.
+	 */
+#ifdef CONFIG_64BIT
+# define VMALLOC_FAULT_TARGET no_context
+#else
+# define VMALLOC_FAULT_TARGET vmalloc_fault
+#endif
+
+	if (unlikely(address >= VMALLOC_START && address <= VMALLOC_END))
+		goto VMALLOC_FAULT_TARGET;
+#ifdef MODULE_START
+	if (unlikely(address >= MODULE_START && address < MODULE_END))
+		goto VMALLOC_FAULT_TARGET;
+#endif
+
+	/*
+	 * If we're in an interrupt or have no user
+	 * context, we must not take the fault..
+	 */
+	if (faulthandler_disabled() || !mm)
+		goto bad_area_nosemaphore;
+
+	if (user_mode(regs))
+		flags |= FAULT_FLAG_USER;
+retry:
+	down_read(&mm->mmap_sem);
+	vma = find_vma(mm, address);
+	if (!vma)
+		goto bad_area;
+	if (vma->vm_start <= address)
+		goto good_area;
+	if (!(vma->vm_flags & VM_GROWSDOWN))
+		goto bad_area;
+	if (expand_stack(vma, address))
+		goto bad_area;
+/*
+ * Ok, we have a good vm_area for this memory access, so
+ * we can handle it..
+ */
+good_area:
+	info.si_code = SEGV_ACCERR;
+
+	if (write) {
+		if (!(vma->vm_flags & VM_WRITE))
+			goto bad_area;
+		flags |= FAULT_FLAG_WRITE;
+	} else {
+		if (cpu_has_rixi) {
+			if (address == regs->cp0_epc && !(vma->vm_flags & VM_EXEC)) {
+#if 0
+				pr_notice("Cpu%d[%s:%d:%0*lx:%ld:%0*lx] XI violation\n",
+					  raw_smp_processor_id(),
+					  current->comm, current->pid,
+					  field, address, write,
+					  field, regs->cp0_epc);
+#endif
+				goto bad_area;
+			}
+			if (!(vma->vm_flags & VM_READ)) {
+#if 0
+				pr_notice("Cpu%d[%s:%d:%0*lx:%ld:%0*lx] RI violation\n",
+					  raw_smp_processor_id(),
+					  current->comm, current->pid,
+					  field, address, write,
+					  field, regs->cp0_epc);
+#endif
+				goto bad_area;
+			}
+		} else {
+			if (!(vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)))
+				goto bad_area;
+		}
+	}
+
+	/*
+	 * If for any reason at all we couldn't handle the fault,
+	 * make sure we exit gracefully rather than endlessly redo
+	 * the fault.
+	 */
+	fault = handle_mm_fault(mm, vma, address, flags);
+
+	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
+		return;
+
+	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
+	if (unlikely(fault & VM_FAULT_ERROR)) {
+		if (fault & VM_FAULT_OOM)
+			goto out_of_memory;
+		else if (fault & VM_FAULT_SIGSEGV)
+			goto bad_area;
+		else if (fault & VM_FAULT_SIGBUS)
+			goto do_sigbus;
+		BUG();
+	}
+	if (flags & FAULT_FLAG_ALLOW_RETRY) {
+		if (fault & VM_FAULT_MAJOR) {
+			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
+						  regs, address);
+			tsk->maj_flt++;
+		} else {
+			perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
+						  regs, address);
+			tsk->min_flt++;
+		}
+		if (fault & VM_FAULT_RETRY) {
+			flags &= ~FAULT_FLAG_ALLOW_RETRY;
+			flags |= FAULT_FLAG_TRIED;
+
+			/*
+			 * No need to up_read(&mm->mmap_sem) as we would
+			 * have already released it in __lock_page_or_retry
+			 * in mm/filemap.c.
+			 */
+
+			goto retry;
+		}
+	}
+
+	up_read(&mm->mmap_sem);
+	return;
+
+/*
+ * Something tried to access memory that isn't in our memory map..
+ * Fix it, but check if it's kernel or user first..
+ */
+bad_area:
+	up_read(&mm->mmap_sem);
+
+bad_area_nosemaphore:
+	/* User mode accesses just cause a SIGSEGV */
+	if (user_mode(regs)) {
+		tsk->thread.cp0_badvaddr = address;
+		tsk->thread.error_code = write;
+		if (show_unhandled_signals &&
+		    unhandled_signal(tsk, SIGSEGV) &&
+		    __ratelimit(&ratelimit_state)) {
+			pr_info("\ndo_page_fault(): sending SIGSEGV to %s for invalid %s %0*lx",
+				tsk->comm,
+				write ? "write access to" : "read access from",
+				field, address);
+			pr_info("epc = %0*lx in", field,
+				(unsigned long) regs->cp0_epc);
+			print_vma_addr(" ", regs->cp0_epc);
+			pr_info("ra  = %0*lx in", field,
+				(unsigned long) regs->regs[31]);
+			print_vma_addr(" ", regs->regs[31]);
+			pr_info("\n");
+		}
+		info.si_signo = SIGSEGV;
+		info.si_errno = 0;
+		/* info.si_code has been set above */
+		info.si_addr = (void __user *) address;
+		force_sig_info(SIGSEGV, &info, tsk);
+		return;
+	}
+
+no_context:
+	/* Are we prepared to handle this kernel fault?	 */
+	if (fixup_exception(regs)) {
+		current->thread.cp0_baduaddr = address;
+		return;
+	}
+
+	/*
+	 * Oops. The kernel tried to access some bad page. We'll have to
+	 * terminate things with extreme prejudice.
+	 */
+	bust_spinlocks(1);
+
+	printk(KERN_ALERT "CPU %d Unable to handle kernel paging request at "
+	       "virtual address %0*lx, epc == %0*lx, ra == %0*lx\n",
+	       raw_smp_processor_id(), field, address, field, regs->cp0_epc,
+	       field,  regs->regs[31]);
+	die("Oops", regs);
+
+out_of_memory:
+	/*
+	 * We ran out of memory, call the OOM killer, and return the userspace
+	 * (which will retry the fault, or kill us if we got oom-killed).
+	 */
+	up_read(&mm->mmap_sem);
+	if (!user_mode(regs))
+		goto no_context;
+	pagefault_out_of_memory();
+	return;
+
+do_sigbus:
+	up_read(&mm->mmap_sem);
+
+	/* Kernel mode? Handle exceptions or die */
+	if (!user_mode(regs))
+		goto no_context;
+	else
+	/*
+	 * Send a sigbus, regardless of whether we were in kernel
+	 * or user mode.
+	 */
+#if 0
+		printk("do_page_fault() #3: sending SIGBUS to %s for "
+		       "invalid %s\n%0*lx (epc == %0*lx, ra == %0*lx)\n",
+		       tsk->comm,
+		       write ? "write access to" : "read access from",
+		       field, address,
+		       field, (unsigned long) regs->cp0_epc,
+		       field, (unsigned long) regs->regs[31]);
+#endif
+	tsk->thread.cp0_badvaddr = address;
+	info.si_signo = SIGBUS;
+	info.si_errno = 0;
+	info.si_code = BUS_ADRERR;
+	info.si_addr = (void __user *) address;
+	force_sig_info(SIGBUS, &info, tsk);
+
+	return;
+#ifndef CONFIG_64BIT
+vmalloc_fault:
+	{
+		/*
+		 * Synchronize this task's top level page-table
+		 * with the 'reference' page table.
+		 *
+		 * Do _not_ use "tsk" here. We might be inside
+		 * an interrupt in the middle of a task switch..
+		 */
+		int offset = __pgd_offset(address);
+		pgd_t *pgd, *pgd_k;
+		pud_t *pud, *pud_k;
+		pmd_t *pmd, *pmd_k;
+		pte_t *pte_k;
+
+		pgd = (pgd_t *) pgd_current[raw_smp_processor_id()] + offset;
+		pgd_k = init_mm.pgd + offset;
+
+		if (!pgd_present(*pgd_k))
+			goto no_context;
+		set_pgd(pgd, *pgd_k);
+
+		pud = pud_offset(pgd, address);
+		pud_k = pud_offset(pgd_k, address);
+		if (!pud_present(*pud_k))
+			goto no_context;
+
+		pmd = pmd_offset(pud, address);
+		pmd_k = pmd_offset(pud_k, address);
+		if (!pmd_present(*pmd_k))
+			goto no_context;
+		set_pmd(pmd, *pmd_k);
+
+		pte_k = pte_offset_kernel(pmd_k, address);
+		if (!pte_present(*pte_k))
+			goto no_context;
+		return;
+	}
+#endif
+}
+
+asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
+	unsigned long write, unsigned long address)
+{
+	enum ctx_state prev_state;
+
+	prev_state = exception_enter();
+	__do_page_fault(regs, write, address);
+	exception_exit(prev_state);
+}