arch/sh64/mm/fault.c - kernel/msm-4.19 - Gitiles

 /*
  * 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.
  *
  * arch/sh64/mm/fault.c
  *
  * Copyright (C) 2000, 2001  Paolo Alberelli
  * Copyright (C) 2003  Richard Curnow (/proc/tlb, bug fixes)
  * Copyright (C) 2003  Paul Mundt
  *
  */

 #include <linux/signal.h>
 #include <linux/rwsem.h>
 #include <linux/sched.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/ptrace.h>
 #include <linux/mman.h>
 #include <linux/mm.h>
 #include <linux/smp.h>
 #include <linux/smp_lock.h>
 #include <linux/interrupt.h>

 #include <asm/system.h>
 #include <asm/io.h>
 #include <asm/tlb.h>
 #include <asm/uaccess.h>
 #include <asm/pgalloc.h>
 #include <asm/mmu_context.h>
 #include <asm/registers.h>		/* required by inline asm statements */

 #if defined(CONFIG_SH64_PROC_TLB)
 #include <linux/init.h>
 #include <linux/proc_fs.h>
 /* Count numbers of tlb refills in each region */
 static unsigned long long calls_to_update_mmu_cache = 0ULL;
 static unsigned long long calls_to_flush_tlb_page   = 0ULL;
 static unsigned long long calls_to_flush_tlb_range  = 0ULL;
 static unsigned long long calls_to_flush_tlb_mm     = 0ULL;
 static unsigned long long calls_to_flush_tlb_all    = 0ULL;
 unsigned long long calls_to_do_slow_page_fault = 0ULL;
 unsigned long long calls_to_do_fast_page_fault = 0ULL;

 /* Count size of ranges for flush_tlb_range */
 static unsigned long long flush_tlb_range_1         = 0ULL;
 static unsigned long long flush_tlb_range_2         = 0ULL;
 static unsigned long long flush_tlb_range_3_4       = 0ULL;
 static unsigned long long flush_tlb_range_5_7       = 0ULL;
 static unsigned long long flush_tlb_range_8_11      = 0ULL;
 static unsigned long long flush_tlb_range_12_15     = 0ULL;
 static unsigned long long flush_tlb_range_16_up     = 0ULL;

 static unsigned long long page_not_present          = 0ULL;

 #endif

 extern void die(const char *,struct pt_regs *,long);

 #define PFLAG(val,flag)   (( (val) & (flag) ) ? #flag : "" )
 #define PPROT(flag) PFLAG(pgprot_val(prot),flag)

 static inline void print_prots(pgprot_t prot)
 {
 	printk("prot is 0x%08lx\n",pgprot_val(prot));

 	printk("%s %s %s %s %s\n",PPROT(_PAGE_SHARED),PPROT(_PAGE_READ),
 	       PPROT(_PAGE_EXECUTE),PPROT(_PAGE_WRITE),PPROT(_PAGE_USER));
 }

 static inline void print_vma(struct vm_area_struct *vma)
 {
 	printk("vma start 0x%08lx\n", vma->vm_start);
 	printk("vma end   0x%08lx\n", vma->vm_end);

 	print_prots(vma->vm_page_prot);
 	printk("vm_flags 0x%08lx\n", vma->vm_flags);
 }

 static inline void print_task(struct task_struct *tsk)
 {
 	printk("Task pid %d\n", tsk->pid);
 }

 static pte_t *lookup_pte(struct mm_struct *mm, unsigned long address)
 {
 	pgd_t *dir;
 	pmd_t *pmd;
 	pte_t *pte;
 	pte_t entry;

 	dir = pgd_offset(mm, address);
 	if (pgd_none(*dir)) {
 		return NULL;
 	}

 	pmd = pmd_offset(dir, address);
 	if (pmd_none(*pmd)) {
 		return NULL;
 	}

 	pte = pte_offset_kernel(pmd, address);
 	entry = *pte;

 	if (pte_none(entry)) {
 		return NULL;
 	}
 	if (!pte_present(entry)) {
 		return NULL;
 	}

 	return pte;
 }

 /*
  * This routine handles page faults.  It determines the address,
  * and the problem, and then passes it off to one of the appropriate
  * routines.
  */
 asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long writeaccess,
 			      unsigned long textaccess, unsigned long address)
 {
 	struct task_struct *tsk;
 	struct mm_struct *mm;
 	struct vm_area_struct * vma;
 	const struct exception_table_entry *fixup;
 	pte_t *pte;

 #if defined(CONFIG_SH64_PROC_TLB)
         ++calls_to_do_slow_page_fault;
 #endif

 	/* SIM
 	 * Note this is now called with interrupts still disabled
 	 * This is to cope with being called for a missing IO port
 	 * address with interupts disabled. This should be fixed as
 	 * soon as we have a better 'fast path' miss handler.
 	 *
 	 * Plus take care how you try and debug this stuff.
 	 * For example, writing debug data to a port which you
 	 * have just faulted on is not going to work.
 	 */

 	tsk = current;
 	mm = tsk->mm;

 	/* Not an IO address, so reenable interrupts */
 	local_irq_enable();

 	/*
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
 	if (in_interrupt() || !mm)
 		goto no_context;

 	/* TLB misses upon some cache flushes get done under cli() */
 	down_read(&mm->mmap_sem);

 	vma = find_vma(mm, address);

 	if (!vma) {
 #ifdef DEBUG_FAULT
 		print_task(tsk);
 		printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
 		       __FUNCTION__,__LINE__,
 		       address,regs->pc,textaccess,writeaccess);
 		show_regs(regs);
 #endif
 		goto bad_area;
 	}
 	if (vma->vm_start <= address) {
 		goto good_area;
 	}

 	if (!(vma->vm_flags & VM_GROWSDOWN)) {
 #ifdef DEBUG_FAULT
 		print_task(tsk);
 		printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
 		       __FUNCTION__,__LINE__,
 		       address,regs->pc,textaccess,writeaccess);
 		show_regs(regs);

 		print_vma(vma);
 #endif
 		goto bad_area;
 	}
 	if (expand_stack(vma, address)) {
 #ifdef DEBUG_FAULT
 		print_task(tsk);
 		printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
 		       __FUNCTION__,__LINE__,
 		       address,regs->pc,textaccess,writeaccess);
 		show_regs(regs);
 #endif
 		goto bad_area;
 	}
 /*
  * Ok, we have a good vm_area for this memory access, so
  * we can handle it..
  */
 good_area:
 	if (textaccess) {
 		if (!(vma->vm_flags & VM_EXEC))
 			goto bad_area;
 	} else {
 		if (writeaccess) {
 			if (!(vma->vm_flags & VM_WRITE))
 				goto bad_area;
 		} else {
 			if (!(vma->vm_flags & VM_READ))
 				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.
 	 */
 survive:
 	switch (handle_mm_fault(mm, vma, address, writeaccess)) {
 	case 1:
 		tsk->min_flt++;
 		break;
 	case 2:
 		tsk->maj_flt++;
 		break;
 	case 0:
 		goto do_sigbus;
 	default:
 		goto out_of_memory;
 	}
 	/* If we get here, the page fault has been handled.  Do the TLB refill
 	   now from the newly-setup PTE, to avoid having to fault again right
 	   away on the same instruction. */
 	pte = lookup_pte (mm, address);
 	if (!pte) {
 		/* From empirical evidence, we can get here, due to
 		   !pte_present(pte).  (e.g. if a swap-in occurs, and the page
 		   is swapped back out again before the process that wanted it
 		   gets rescheduled?) */
 		goto no_pte;
 	}

 	__do_tlb_refill(address, textaccess, pte);

 no_pte:

 	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:
 #ifdef DEBUG_FAULT
 	printk("fault:bad area\n");
 #endif
 	up_read(&mm->mmap_sem);

 	if (user_mode(regs)) {
 		static int count=0;
 		siginfo_t info;
 		if (count < 4) {
 			/* This is really to help debug faults when starting
 			 * usermode, so only need a few */
 			count++;
 			printk("user mode bad_area address=%08lx pid=%d (%s) pc=%08lx\n",
 				address, current->pid, current->comm,
 				(unsigned long) regs->pc);
 #if 0
 			show_regs(regs);
 #endif
 		}
 		if (tsk->pid == 1) {
 			panic("INIT had user mode bad_area\n");
 		}
 		tsk->thread.address = address;
 		tsk->thread.error_code = writeaccess;
 		info.si_signo = SIGSEGV;
 		info.si_errno = 0;
 		info.si_addr = (void *) address;
 		force_sig_info(SIGSEGV, &info, tsk);
 		return;
 	}

 no_context:
 #ifdef DEBUG_FAULT
 	printk("fault:No context\n");
 #endif
 	/* Are we prepared to handle this kernel fault?  */
 	fixup = search_exception_tables(regs->pc);
 	if (fixup) {
 		regs->pc = fixup->fixup;
 		return;
 	}

 /*
  * Oops. The kernel tried to access some bad page. We'll have to
  * terminate things with extreme prejudice.
  *
  */
 	if (address < PAGE_SIZE)
 		printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
 	else
 		printk(KERN_ALERT "Unable to handle kernel paging request");
 	printk(" at virtual address %08lx\n", address);
 	printk(KERN_ALERT "pc = %08Lx%08Lx\n", regs->pc >> 32, regs->pc & 0xffffffff);
 	die("Oops", regs, writeaccess);
 	do_exit(SIGKILL);

 /*
  * We ran out of memory, or some other thing happened to us that made
  * us unable to handle the page fault gracefully.
  */
 out_of_memory:
 	if (current->pid == 1) {
 		panic("INIT out of memory\n");
 		yield();
 		goto survive;
 	}
 	printk("fault:Out of memory\n");
 	up_read(&mm->mmap_sem);
 	if (current->pid == 1) {
 		yield();
 		down_read(&mm->mmap_sem);
 		goto survive;
 	}
 	printk("VM: killing process %s\n", tsk->comm);
 	if (user_mode(regs))
 		do_exit(SIGKILL);
 	goto no_context;

 do_sigbus:
 	printk("fault:Do sigbus\n");
 	up_read(&mm->mmap_sem);

 	/*
 	 * Send a sigbus, regardless of whether we were in kernel
 	 * or user mode.
 	 */
 	tsk->thread.address = address;
 	tsk->thread.error_code = writeaccess;
 	tsk->thread.trap_no = 14;
 	force_sig(SIGBUS, tsk);

 	/* Kernel mode? Handle exceptions or die */
 	if (!user_mode(regs))
 		goto no_context;
 }


 void flush_tlb_all(void);

 void update_mmu_cache(struct vm_area_struct * vma,
 			unsigned long address, pte_t pte)
 {
 #if defined(CONFIG_SH64_PROC_TLB)
 	++calls_to_update_mmu_cache;
 #endif

 	/*
 	 * This appears to get called once for every pte entry that gets
 	 * established => I don't think it's efficient to try refilling the
 	 * TLBs with the pages - some may not get accessed even.  Also, for
 	 * executable pages, it is impossible to determine reliably here which
 	 * TLB they should be mapped into (or both even).
 	 *
 	 * So, just do nothing here and handle faults on demand.  In the
 	 * TLBMISS handling case, the refill is now done anyway after the pte
 	 * has been fixed up, so that deals with most useful cases.
 	 */
 }

 static void __flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 {
 	unsigned long long match, pteh=0, lpage;
 	unsigned long tlb;
 	struct mm_struct *mm;

 	mm = vma->vm_mm;

 	if (mm->context == NO_CONTEXT)
 		return;

 	/*
 	 * Sign-extend based on neff.
 	 */
 	lpage = (page & NEFF_SIGN) ? (page | NEFF_MASK) : page;
 	match = ((mm->context & MMU_CONTEXT_ASID_MASK) << PTEH_ASID_SHIFT) | PTEH_VALID;
 	match |= lpage;

         /* Do ITLB : don't bother for pages in non-exectutable VMAs */
 	if (vma->vm_flags & VM_EXEC) {
 		for_each_itlb_entry(tlb) {
 			asm volatile ("getcfg	%1, 0, %0"
 				      : "=r" (pteh)
 				      : "r" (tlb) );

 			if (pteh == match) {
 				__flush_tlb_slot(tlb);
 				break;
 			}

 		}
 	}

         /* Do DTLB : any page could potentially be in here. */
 	for_each_dtlb_entry(tlb) {
 		asm volatile ("getcfg	%1, 0, %0"
 			      : "=r" (pteh)
 			      : "r" (tlb) );

 		if (pteh == match) {
 			__flush_tlb_slot(tlb);
 			break;
 		}

 	}
 }

 void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 {
 	unsigned long flags;

 #if defined(CONFIG_SH64_PROC_TLB)
         ++calls_to_flush_tlb_page;
 #endif

 	if (vma->vm_mm) {
 		page &= PAGE_MASK;
 		local_irq_save(flags);
 		__flush_tlb_page(vma, page);
 		local_irq_restore(flags);
 	}
 }

 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 		     unsigned long end)
 {
 	unsigned long flags;
 	unsigned long long match, pteh=0, pteh_epn, pteh_low;
 	unsigned long tlb;
 	struct mm_struct *mm;

 	mm = vma->vm_mm;

 #if defined(CONFIG_SH64_PROC_TLB)
 	++calls_to_flush_tlb_range;

 	{
 		unsigned long size = (end - 1) - start;
 		size >>= 12; /* divide by PAGE_SIZE */
 		size++; /* end=start+4096 => 1 page */
 		switch (size) {
 		  case  1        : flush_tlb_range_1++;     break;
 		  case  2        : flush_tlb_range_2++;     break;
 		  case  3 ...  4 : flush_tlb_range_3_4++;   break;
 		  case  5 ...  7 : flush_tlb_range_5_7++;   break;
 		  case  8 ... 11 : flush_tlb_range_8_11++;  break;
 		  case 12 ... 15 : flush_tlb_range_12_15++; break;
 		  default        : flush_tlb_range_16_up++; break;
 		}
 	}
 #endif

 	if (mm->context == NO_CONTEXT)
 		return;

 	local_irq_save(flags);

 	start &= PAGE_MASK;
 	end &= PAGE_MASK;

 	match = ((mm->context & MMU_CONTEXT_ASID_MASK) << PTEH_ASID_SHIFT) | PTEH_VALID;

 	/* Flush ITLB */
 	for_each_itlb_entry(tlb) {
 		asm volatile ("getcfg	%1, 0, %0"
 			      : "=r" (pteh)
 			      : "r" (tlb) );

 		pteh_epn = pteh & PAGE_MASK;
 		pteh_low = pteh & ~PAGE_MASK;

 		if (pteh_low == match && pteh_epn >= start && pteh_epn <= end)
 			__flush_tlb_slot(tlb);
 	}

 	/* Flush DTLB */
 	for_each_dtlb_entry(tlb) {
 		asm volatile ("getcfg	%1, 0, %0"
 			      : "=r" (pteh)
 			      : "r" (tlb) );

 		pteh_epn = pteh & PAGE_MASK;
 		pteh_low = pteh & ~PAGE_MASK;

 		if (pteh_low == match && pteh_epn >= start && pteh_epn <= end)
 			__flush_tlb_slot(tlb);
 	}

 	local_irq_restore(flags);
 }

 void flush_tlb_mm(struct mm_struct *mm)
 {
 	unsigned long flags;

 #if defined(CONFIG_SH64_PROC_TLB)
 	++calls_to_flush_tlb_mm;
 #endif

 	if (mm->context == NO_CONTEXT)
 		return;

 	local_irq_save(flags);

 	mm->context=NO_CONTEXT;
 	if(mm==current->mm)
 		activate_context(mm);

 	local_irq_restore(flags);

 }

 void flush_tlb_all(void)
 {
 	/* Invalidate all, including shared pages, excluding fixed TLBs */

 	unsigned long flags, tlb;

 #if defined(CONFIG_SH64_PROC_TLB)
 	++calls_to_flush_tlb_all;
 #endif

 	local_irq_save(flags);

 	/* Flush each ITLB entry */
 	for_each_itlb_entry(tlb) {
 		__flush_tlb_slot(tlb);
 	}

 	/* Flush each DTLB entry */
 	for_each_dtlb_entry(tlb) {
 		__flush_tlb_slot(tlb);
 	}

 	local_irq_restore(flags);
 }

 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
 {
         /* FIXME: Optimize this later.. */
         flush_tlb_all();
 }

 #if defined(CONFIG_SH64_PROC_TLB)
 /* Procfs interface to read the performance information */

 static int
 tlb_proc_info(char *buf, char **start, off_t fpos, int length, int *eof, void *data)
 {
   int len=0;
   len += sprintf(buf+len, "do_fast_page_fault   called %12lld times\n", calls_to_do_fast_page_fault);
   len += sprintf(buf+len, "do_slow_page_fault   called %12lld times\n", calls_to_do_slow_page_fault);
   len += sprintf(buf+len, "update_mmu_cache     called %12lld times\n", calls_to_update_mmu_cache);
   len += sprintf(buf+len, "flush_tlb_page       called %12lld times\n", calls_to_flush_tlb_page);
   len += sprintf(buf+len, "flush_tlb_range      called %12lld times\n", calls_to_flush_tlb_range);
   len += sprintf(buf+len, "flush_tlb_mm         called %12lld times\n", calls_to_flush_tlb_mm);
   len += sprintf(buf+len, "flush_tlb_all        called %12lld times\n", calls_to_flush_tlb_all);
   len += sprintf(buf+len, "flush_tlb_range_sizes\n"
                           " 1      : %12lld\n"
                           " 2      : %12lld\n"
                           " 3 -  4 : %12lld\n"
                           " 5 -  7 : %12lld\n"
                           " 8 - 11 : %12lld\n"
                           "12 - 15 : %12lld\n"
                           "16+     : %12lld\n",
                           flush_tlb_range_1, flush_tlb_range_2, flush_tlb_range_3_4,
                           flush_tlb_range_5_7, flush_tlb_range_8_11, flush_tlb_range_12_15,
                           flush_tlb_range_16_up);
   len += sprintf(buf+len, "page not present           %12lld times\n", page_not_present);
   *eof = 1;
   return len;
 }

 static int __init register_proc_tlb(void)
 {
   create_proc_read_entry("tlb", 0, NULL, tlb_proc_info, NULL);
   return 0;
 }

 __initcall(register_proc_tlb);

 #endif
	/*
	* 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.
	*
	* arch/sh64/mm/fault.c
	*
	* Copyright (C) 2000, 2001 Paolo Alberelli
	* Copyright (C) 2003 Richard Curnow (/proc/tlb, bug fixes)
	* Copyright (C) 2003 Paul Mundt
	*
	*/

	#include <linux/signal.h>
	#include <linux/rwsem.h>
	#include <linux/sched.h>
	#include <linux/kernel.h>
	#include <linux/errno.h>
	#include <linux/string.h>
	#include <linux/types.h>
	#include <linux/ptrace.h>
	#include <linux/mman.h>
	#include <linux/mm.h>
	#include <linux/smp.h>
	#include <linux/smp_lock.h>
	#include <linux/interrupt.h>

	#include <asm/system.h>
	#include <asm/io.h>
	#include <asm/tlb.h>
	#include <asm/uaccess.h>
	#include <asm/pgalloc.h>
	#include <asm/mmu_context.h>
	#include <asm/registers.h> /* required by inline asm statements */

	#if defined(CONFIG_SH64_PROC_TLB)
	#include <linux/init.h>
	#include <linux/proc_fs.h>
	/* Count numbers of tlb refills in each region */
	static unsigned long long calls_to_update_mmu_cache = 0ULL;
	static unsigned long long calls_to_flush_tlb_page = 0ULL;
	static unsigned long long calls_to_flush_tlb_range = 0ULL;
	static unsigned long long calls_to_flush_tlb_mm = 0ULL;
	static unsigned long long calls_to_flush_tlb_all = 0ULL;
	unsigned long long calls_to_do_slow_page_fault = 0ULL;
	unsigned long long calls_to_do_fast_page_fault = 0ULL;

	/* Count size of ranges for flush_tlb_range */
	static unsigned long long flush_tlb_range_1 = 0ULL;
	static unsigned long long flush_tlb_range_2 = 0ULL;
	static unsigned long long flush_tlb_range_3_4 = 0ULL;
	static unsigned long long flush_tlb_range_5_7 = 0ULL;
	static unsigned long long flush_tlb_range_8_11 = 0ULL;
	static unsigned long long flush_tlb_range_12_15 = 0ULL;
	static unsigned long long flush_tlb_range_16_up = 0ULL;

	static unsigned long long page_not_present = 0ULL;

	#endif

	extern void die(const char ,struct pt_regs ,long);

	#define PFLAG(val,flag) (( (val) & (flag) ) ? #flag : "" )
	#define PPROT(flag) PFLAG(pgprot_val(prot),flag)

	static inline void print_prots(pgprot_t prot)
	{
	printk("prot is 0x%08lx\n",pgprot_val(prot));

	printk("%s %s %s %s %s\n",PPROT(_PAGE_SHARED),PPROT(_PAGE_READ),
	PPROT(_PAGE_EXECUTE),PPROT(_PAGE_WRITE),PPROT(_PAGE_USER));
	}

	static inline void print_vma(struct vm_area_struct *vma)
	{
	printk("vma start 0x%08lx\n", vma->vm_start);
	printk("vma end 0x%08lx\n", vma->vm_end);

	print_prots(vma->vm_page_prot);
	printk("vm_flags 0x%08lx\n", vma->vm_flags);
	}

	static inline void print_task(struct task_struct *tsk)
	{
	printk("Task pid %d\n", tsk->pid);
	}

	static pte_t lookup_pte(struct mm_struct mm, unsigned long address)
	{
	pgd_t *dir;
	pmd_t *pmd;
	pte_t *pte;
	pte_t entry;

	dir = pgd_offset(mm, address);
	if (pgd_none(*dir)) {
	return NULL;
	}

	pmd = pmd_offset(dir, address);
	if (pmd_none(*pmd)) {
	return NULL;
	}

	pte = pte_offset_kernel(pmd, address);
	entry = *pte;

	if (pte_none(entry)) {
	return NULL;
	}
	if (!pte_present(entry)) {
	return NULL;
	}

	return pte;
	}

	/*
	* This routine handles page faults. It determines the address,
	* and the problem, and then passes it off to one of the appropriate
	* routines.
	*/
	asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long writeaccess,
	unsigned long textaccess, unsigned long address)
	{
	struct task_struct *tsk;
	struct mm_struct *mm;
	struct vm_area_struct * vma;
	const struct exception_table_entry *fixup;
	pte_t *pte;

	#if defined(CONFIG_SH64_PROC_TLB)
	++calls_to_do_slow_page_fault;
	#endif

	/* SIM
	* Note this is now called with interrupts still disabled
	* This is to cope with being called for a missing IO port
	* address with interupts disabled. This should be fixed as
	* soon as we have a better 'fast path' miss handler.
	*
	* Plus take care how you try and debug this stuff.
	* For example, writing debug data to a port which you
	* have just faulted on is not going to work.
	*/

	tsk = current;
	mm = tsk->mm;

	/* Not an IO address, so reenable interrupts */
	local_irq_enable();

	/*
	* If we're in an interrupt or have no user
	* context, we must not take the fault..
	*/
	if (in_interrupt() \|\| !mm)
	goto no_context;

	/* TLB misses upon some cache flushes get done under cli() */
	down_read(&mm->mmap_sem);

	vma = find_vma(mm, address);

	if (!vma) {
	#ifdef DEBUG_FAULT
	print_task(tsk);
	printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
	__FUNCTION__,__LINE__,
	address,regs->pc,textaccess,writeaccess);
	show_regs(regs);
	#endif
	goto bad_area;
	}
	if (vma->vm_start <= address) {
	goto good_area;
	}

	if (!(vma->vm_flags & VM_GROWSDOWN)) {
	#ifdef DEBUG_FAULT
	print_task(tsk);
	printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
	__FUNCTION__,__LINE__,
	address,regs->pc,textaccess,writeaccess);
	show_regs(regs);

	print_vma(vma);
	#endif
	goto bad_area;
	}
	if (expand_stack(vma, address)) {
	#ifdef DEBUG_FAULT
	print_task(tsk);
	printk("%s:%d fault, address is 0x%08x PC %016Lx textaccess %d writeaccess %d\n",
	__FUNCTION__,__LINE__,
	address,regs->pc,textaccess,writeaccess);
	show_regs(regs);
	#endif
	goto bad_area;
	}
	/*
	* Ok, we have a good vm_area for this memory access, so
	* we can handle it..
	*/
	good_area:
	if (textaccess) {
	if (!(vma->vm_flags & VM_EXEC))
	goto bad_area;
	} else {
	if (writeaccess) {
	if (!(vma->vm_flags & VM_WRITE))
	goto bad_area;
	} else {
	if (!(vma->vm_flags & VM_READ))
	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.
	*/
	survive:
	switch (handle_mm_fault(mm, vma, address, writeaccess)) {
	case 1:
	tsk->min_flt++;
	break;
	case 2:
	tsk->maj_flt++;
	break;
	case 0:
	goto do_sigbus;
	default:
	goto out_of_memory;
	}
	/* If we get here, the page fault has been handled. Do the TLB refill
	now from the newly-setup PTE, to avoid having to fault again right
	away on the same instruction. */
	pte = lookup_pte (mm, address);
	if (!pte) {
	/* From empirical evidence, we can get here, due to
	!pte_present(pte). (e.g. if a swap-in occurs, and the page
	is swapped back out again before the process that wanted it
	gets rescheduled?) */
	goto no_pte;
	}

	__do_tlb_refill(address, textaccess, pte);

	no_pte:

	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:
	#ifdef DEBUG_FAULT
	printk("fault:bad area\n");
	#endif
	up_read(&mm->mmap_sem);

	if (user_mode(regs)) {
	static int count=0;
	siginfo_t info;
	if (count < 4) {
	/* This is really to help debug faults when starting
	* usermode, so only need a few */
	count++;
	printk("user mode bad_area address=%08lx pid=%d (%s) pc=%08lx\n",
	address, current->pid, current->comm,
	(unsigned long) regs->pc);
	#if 0
	show_regs(regs);
	#endif
	}
	if (tsk->pid == 1) {
	panic("INIT had user mode bad_area\n");
	}
	tsk->thread.address = address;
	tsk->thread.error_code = writeaccess;
	info.si_signo = SIGSEGV;
	info.si_errno = 0;
	info.si_addr = (void *) address;
	force_sig_info(SIGSEGV, &info, tsk);
	return;
	}

	no_context:
	#ifdef DEBUG_FAULT
	printk("fault:No context\n");
	#endif
	/* Are we prepared to handle this kernel fault? */
	fixup = search_exception_tables(regs->pc);
	if (fixup) {
	regs->pc = fixup->fixup;
	return;
	}

	/*
	* Oops. The kernel tried to access some bad page. We'll have to
	* terminate things with extreme prejudice.
	*
	*/
	if (address < PAGE_SIZE)
	printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
	else
	printk(KERN_ALERT "Unable to handle kernel paging request");
	printk(" at virtual address %08lx\n", address);
	printk(KERN_ALERT "pc = %08Lx%08Lx\n", regs->pc >> 32, regs->pc & 0xffffffff);
	die("Oops", regs, writeaccess);
	do_exit(SIGKILL);

	/*
	* We ran out of memory, or some other thing happened to us that made
	* us unable to handle the page fault gracefully.
	*/
	out_of_memory:
	if (current->pid == 1) {
	panic("INIT out of memory\n");
	yield();
	goto survive;
	}
	printk("fault:Out of memory\n");
	up_read(&mm->mmap_sem);
	if (current->pid == 1) {
	yield();
	down_read(&mm->mmap_sem);
	goto survive;
	}
	printk("VM: killing process %s\n", tsk->comm);
	if (user_mode(regs))
	do_exit(SIGKILL);
	goto no_context;

	do_sigbus:
	printk("fault:Do sigbus\n");
	up_read(&mm->mmap_sem);

	/*
	* Send a sigbus, regardless of whether we were in kernel
	* or user mode.
	*/
	tsk->thread.address = address;
	tsk->thread.error_code = writeaccess;
	tsk->thread.trap_no = 14;
	force_sig(SIGBUS, tsk);

	/* Kernel mode? Handle exceptions or die */
	if (!user_mode(regs))
	goto no_context;
	}


	void flush_tlb_all(void);

	void update_mmu_cache(struct vm_area_struct * vma,
	unsigned long address, pte_t pte)
	{
	#if defined(CONFIG_SH64_PROC_TLB)
	++calls_to_update_mmu_cache;
	#endif

	/*
	* This appears to get called once for every pte entry that gets
	* established => I don't think it's efficient to try refilling the
	* TLBs with the pages - some may not get accessed even. Also, for
	* executable pages, it is impossible to determine reliably here which
	* TLB they should be mapped into (or both even).
	*
	* So, just do nothing here and handle faults on demand. In the
	* TLBMISS handling case, the refill is now done anyway after the pte
	* has been fixed up, so that deals with most useful cases.
	*/
	}

	static void __flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
	{
	unsigned long long match, pteh=0, lpage;
	unsigned long tlb;
	struct mm_struct *mm;

	mm = vma->vm_mm;

	if (mm->context == NO_CONTEXT)
	return;

	/*
	* Sign-extend based on neff.
	*/
	lpage = (page & NEFF_SIGN) ? (page \| NEFF_MASK) : page;
	match = ((mm->context & MMU_CONTEXT_ASID_MASK) << PTEH_ASID_SHIFT) \| PTEH_VALID;
	match \|= lpage;

	/* Do ITLB : don't bother for pages in non-exectutable VMAs */
	if (vma->vm_flags & VM_EXEC) {
	for_each_itlb_entry(tlb) {
	asm volatile ("getcfg %1, 0, %0"
	: "=r" (pteh)
	: "r" (tlb) );

	if (pteh == match) {
	__flush_tlb_slot(tlb);
	break;
	}

	}
	}

	/* Do DTLB : any page could potentially be in here. */
	for_each_dtlb_entry(tlb) {
	asm volatile ("getcfg %1, 0, %0"
	: "=r" (pteh)
	: "r" (tlb) );

	if (pteh == match) {
	__flush_tlb_slot(tlb);
	break;
	}

	}
	}

	void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
	{
	unsigned long flags;

	#if defined(CONFIG_SH64_PROC_TLB)
	++calls_to_flush_tlb_page;
	#endif

	if (vma->vm_mm) {
	page &= PAGE_MASK;
	local_irq_save(flags);
	__flush_tlb_page(vma, page);
	local_irq_restore(flags);
	}
	}

	void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
	unsigned long end)
	{
	unsigned long flags;
	unsigned long long match, pteh=0, pteh_epn, pteh_low;
	unsigned long tlb;
	struct mm_struct *mm;

	mm = vma->vm_mm;

	#if defined(CONFIG_SH64_PROC_TLB)
	++calls_to_flush_tlb_range;

	{
	unsigned long size = (end - 1) - start;
	size >>= 12; /* divide by PAGE_SIZE */
	size++; /* end=start+4096 => 1 page */
	switch (size) {
	case 1 : flush_tlb_range_1++; break;
	case 2 : flush_tlb_range_2++; break;
	case 3 ... 4 : flush_tlb_range_3_4++; break;
	case 5 ... 7 : flush_tlb_range_5_7++; break;
	case 8 ... 11 : flush_tlb_range_8_11++; break;
	case 12 ... 15 : flush_tlb_range_12_15++; break;
	default : flush_tlb_range_16_up++; break;
	}
	}
	#endif

	if (mm->context == NO_CONTEXT)
	return;

	local_irq_save(flags);

	start &= PAGE_MASK;
	end &= PAGE_MASK;

	match = ((mm->context & MMU_CONTEXT_ASID_MASK) << PTEH_ASID_SHIFT) \| PTEH_VALID;

	/* Flush ITLB */
	for_each_itlb_entry(tlb) {
	asm volatile ("getcfg %1, 0, %0"
	: "=r" (pteh)
	: "r" (tlb) );

	pteh_epn = pteh & PAGE_MASK;
	pteh_low = pteh & ~PAGE_MASK;

	if (pteh_low == match && pteh_epn >= start && pteh_epn <= end)
	__flush_tlb_slot(tlb);
	}

	/* Flush DTLB */
	for_each_dtlb_entry(tlb) {
	asm volatile ("getcfg %1, 0, %0"
	: "=r" (pteh)
	: "r" (tlb) );

	pteh_epn = pteh & PAGE_MASK;
	pteh_low = pteh & ~PAGE_MASK;

	if (pteh_low == match && pteh_epn >= start && pteh_epn <= end)
	__flush_tlb_slot(tlb);
	}

	local_irq_restore(flags);
	}

	void flush_tlb_mm(struct mm_struct *mm)
	{
	unsigned long flags;

	#if defined(CONFIG_SH64_PROC_TLB)
	++calls_to_flush_tlb_mm;
	#endif

	if (mm->context == NO_CONTEXT)
	return;

	local_irq_save(flags);

	mm->context=NO_CONTEXT;
	if(mm==current->mm)
	activate_context(mm);

	local_irq_restore(flags);

	}

	void flush_tlb_all(void)
	{
	/* Invalidate all, including shared pages, excluding fixed TLBs */

	unsigned long flags, tlb;

	#if defined(CONFIG_SH64_PROC_TLB)
	++calls_to_flush_tlb_all;
	#endif

	local_irq_save(flags);

	/* Flush each ITLB entry */
	for_each_itlb_entry(tlb) {
	__flush_tlb_slot(tlb);
	}

	/* Flush each DTLB entry */
	for_each_dtlb_entry(tlb) {
	__flush_tlb_slot(tlb);
	}

	local_irq_restore(flags);
	}

	void flush_tlb_kernel_range(unsigned long start, unsigned long end)
	{
	/* FIXME: Optimize this later.. */
	flush_tlb_all();
	}

	#if defined(CONFIG_SH64_PROC_TLB)
	/* Procfs interface to read the performance information */

	static int
	tlb_proc_info(char buf, char start, off_t fpos, int length, int eof, void *data)
	{
	int len=0;
	len += sprintf(buf+len, "do_fast_page_fault called %12lld times\n", calls_to_do_fast_page_fault);
	len += sprintf(buf+len, "do_slow_page_fault called %12lld times\n", calls_to_do_slow_page_fault);
	len += sprintf(buf+len, "update_mmu_cache called %12lld times\n", calls_to_update_mmu_cache);
	len += sprintf(buf+len, "flush_tlb_page called %12lld times\n", calls_to_flush_tlb_page);
	len += sprintf(buf+len, "flush_tlb_range called %12lld times\n", calls_to_flush_tlb_range);
	len += sprintf(buf+len, "flush_tlb_mm called %12lld times\n", calls_to_flush_tlb_mm);
	len += sprintf(buf+len, "flush_tlb_all called %12lld times\n", calls_to_flush_tlb_all);
	len += sprintf(buf+len, "flush_tlb_range_sizes\n"
	" 1 : %12lld\n"
	" 2 : %12lld\n"
	" 3 - 4 : %12lld\n"
	" 5 - 7 : %12lld\n"
	" 8 - 11 : %12lld\n"
	"12 - 15 : %12lld\n"
	"16+ : %12lld\n",
	flush_tlb_range_1, flush_tlb_range_2, flush_tlb_range_3_4,
	flush_tlb_range_5_7, flush_tlb_range_8_11, flush_tlb_range_12_15,
	flush_tlb_range_16_up);
	len += sprintf(buf+len, "page not present %12lld times\n", page_not_present);
	*eof = 1;
	return len;
	}

	static int __init register_proc_tlb(void)
	{
	create_proc_read_entry("tlb", 0, NULL, tlb_proc_info, NULL);
	return 0;
	}

	__initcall(register_proc_tlb);

	#endif