[mirror_ubuntu-focal-kernel.git] / arch / mn10300 / mm / fault.c

/* MN10300 MMU Fault handler
 *
 * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Modified by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#include <linux/signal.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/interrupt.h>
#include <linux/init.h>
#include <linux/vt_kern.h>		/* For unblank_screen() */

#include <asm/uaccess.h>
#include <asm/pgalloc.h>
#include <asm/hardirq.h>
#include <asm/cpu-regs.h>
#include <asm/debugger.h>
#include <asm/gdb-stub.h>

/*
 * Unlock any spinlocks which will prevent us from getting the
 * message out
 */
void bust_spinlocks(int yes)
{
	if (yes) {
		oops_in_progress = 1;
	} else {
		int loglevel_save = console_loglevel;
#ifdef CONFIG_VT
		unblank_screen();
#endif
		oops_in_progress = 0;
		/*
		 * OK, the message is on the console.  Now we call printk()
		 * without oops_in_progress set so that printk will give klogd
		 * a poke.  Hold onto your hats...
		 */
		console_loglevel = 15;	/* NMI oopser may have shut the console
					 * up */
		printk(" ");
		console_loglevel = loglevel_save;
	}
}

void do_BUG(const char *file, int line)
{
	bust_spinlocks(1);
	printk(KERN_EMERG "------------[ cut here ]------------\n");
	printk(KERN_EMERG "kernel BUG at %s:%d!\n", file, line);
}

#if 0
static void print_pagetable_entries(pgd_t *pgdir, unsigned long address)
{
	pgd_t *pgd;
	pmd_t *pmd;
	pte_t *pte;

	pgd = pgdir + __pgd_offset(address);
	printk(KERN_DEBUG "pgd entry %p: %016Lx\n",
	       pgd, (long long) pgd_val(*pgd));

	if (!pgd_present(*pgd)) {
		printk(KERN_DEBUG "... pgd not present!\n");
		return;
	}
	pmd = pmd_offset(pgd, address);
	printk(KERN_DEBUG "pmd entry %p: %016Lx\n",
	       pmd, (long long)pmd_val(*pmd));

	if (!pmd_present(*pmd)) {
		printk(KERN_DEBUG "... pmd not present!\n");
		return;
	}
	pte = pte_offset(pmd, address);
	printk(KERN_DEBUG "pte entry %p: %016Lx\n",
	       pte, (long long) pte_val(*pte));

	if (!pte_present(*pte))
		printk(KERN_DEBUG "... pte not present!\n");
}
#endif

/*
 * This routine handles page faults.  It determines the address,
 * and the problem, and then passes it off to one of the appropriate
 * routines.
 *
 * fault_code:
 * - LSW: either MMUFCR_IFC or MMUFCR_DFC as appropriate
 * - MSW: 0 if data access, 1 if instruction access
 * - bit 0: TLB miss flag
 * - bit 1: initial write
 * - bit 2: page invalid
 * - bit 3: protection violation
 * - bit 4: accessor (0=user 1=kernel)
 * - bit 5: 0=read 1=write
 * - bit 6-8: page protection spec
 * - bit 9: illegal address
 * - bit 16: 0=data 1=ins
 *
 */
asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code,
			      unsigned long address)
{
	struct vm_area_struct *vma;
	struct task_struct *tsk;
	struct mm_struct *mm;
	unsigned long page;
	siginfo_t info;
	int fault;
	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;

#ifdef CONFIG_GDBSTUB
	/* handle GDB stub causing a fault */
	if (gdbstub_busy) {
		gdbstub_exception(regs, TBR & TBR_INT_CODE);
		return;
	}
#endif

#if 0
	printk(KERN_DEBUG "--- do_page_fault(%p,%s:%04lx,%08lx)\n",
	       regs,
	       fault_code & 0x10000 ? "ins" : "data",
	       fault_code & 0xffff, address);
#endif

	tsk = current;

	/*
	 * 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.
	 *
	 * This verifies that the fault happens in kernel space
	 * and that the fault was a page not present (invalid) error
	 */
	if (address >= VMALLOC_START && address < VMALLOC_END &&
	    (fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR &&
	    (fault_code & MMUFCR_xFC_PGINVAL) == MMUFCR_xFC_PGINVAL
	    )
		goto vmalloc_fault;

	mm = tsk->mm;
	info.si_code = SEGV_MAPERR;

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

	if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR)
		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 ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) {
		/* accessing the stack below the stack pointer is always a
		 * bug */
		if ((address & PAGE_MASK) + 2 * PAGE_SIZE < regs->sp) {
#if 0
			printk(KERN_WARNING
			       "[%d] ### Access below stack @%lx (sp=%lx)\n",
			       current->pid, address, regs->sp);
			printk(KERN_WARNING
			       "vma [%08x - %08x]\n",
			       vma->vm_start, vma->vm_end);
			show_registers(regs);
			printk(KERN_WARNING
			       "[%d] ### Code: [%08lx]"
			       " %02x %02x %02x %02x %02x %02x %02x %02x\n",
			       current->pid,
			       regs->pc,
			       ((u8 *) regs->pc)[0],
			       ((u8 *) regs->pc)[1],
			       ((u8 *) regs->pc)[2],
			       ((u8 *) regs->pc)[3],
			       ((u8 *) regs->pc)[4],
			       ((u8 *) regs->pc)[5],
			       ((u8 *) regs->pc)[6],
			       ((u8 *) regs->pc)[7]
			       );
#endif
			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;
	switch (fault_code & (MMUFCR_xFC_PGINVAL|MMUFCR_xFC_TYPE)) {
	default:	/* 3: write, present */
	case MMUFCR_xFC_TYPE_WRITE:
#ifdef TEST_VERIFY_AREA
		if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR)
			printk(KERN_DEBUG "WP fault at %08lx\n", regs->pc);
#endif
		/* write to absent page */
	case MMUFCR_xFC_PGINVAL | MMUFCR_xFC_TYPE_WRITE:
		if (!(vma->vm_flags & VM_WRITE))
			goto bad_area;
		flags |= FAULT_FLAG_WRITE;
		break;

		/* read from protected page */
	case MMUFCR_xFC_TYPE_READ:
		goto bad_area;

		/* read from absent page present */
	case MMUFCR_xFC_PGINVAL | MMUFCR_xFC_TYPE_READ:
		if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
			goto bad_area;
		break;
	}

	/*
	 * 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;

	if (unlikely(fault & VM_FAULT_ERROR)) {
		if (fault & VM_FAULT_OOM)
			goto out_of_memory;
		else if (fault & VM_FAULT_SIGBUS)
			goto do_sigbus;
		BUG();
	}
	if (flags & FAULT_FLAG_ALLOW_RETRY) {
		if (fault & VM_FAULT_MAJOR)
			current->maj_flt++;
		else
			current->min_flt++;
		if (fault & VM_FAULT_RETRY) {
			flags &= ~FAULT_FLAG_ALLOW_RETRY;

			 /* 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);

	/* User mode accesses just cause a SIGSEGV */
	if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) {
		info.si_signo = SIGSEGV;
		info.si_errno = 0;
		/* info.si_code has been set above */
		info.si_addr = (void *)address;
		force_sig_info(SIGSEGV, &info, tsk);
		return;
	}

no_context:
	/* Are we prepared to handle this kernel fault?  */
	if (fixup_exception(regs))
		return;

/*
 * Oops. The kernel tried to access some bad page. We'll have to
 * terminate things with extreme prejudice.
 */

	bust_spinlocks(1);

	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(" printing pc:\n");
	printk(KERN_ALERT "%08lx\n", regs->pc);

	debugger_intercept(fault_code & 0x00010000 ? EXCEP_IAERROR : EXCEP_DAERROR,
			   SIGSEGV, SEGV_ACCERR, regs);

	page = PTBR;
	page = ((unsigned long *) __va(page))[address >> 22];
	printk(KERN_ALERT "*pde = %08lx\n", page);
	if (page & 1) {
		page &= PAGE_MASK;
		address &= 0x003ff000;
		page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT];
		printk(KERN_ALERT "*pte = %08lx\n", page);
	}

	die("Oops", regs, fault_code);
	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:
	up_read(&mm->mmap_sem);
	if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) {
		pagefault_out_of_memory();
		return;
	}
	goto no_context;

do_sigbus:
	up_read(&mm->mmap_sem);

	/*
	 * Send a sigbus, regardless of whether we were in kernel
	 * or user mode.
	 */
	info.si_signo = SIGBUS;
	info.si_errno = 0;
	info.si_code = BUS_ADRERR;
	info.si_addr = (void *)address;
	force_sig_info(SIGBUS, &info, tsk);

	/* Kernel mode? Handle exceptions or die */
	if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR)
		goto no_context;
	return;

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 index = pgd_index(address);
		pgd_t *pgd, *pgd_k;
		pud_t *pud, *pud_k;
		pmd_t *pmd, *pmd_k;
		pte_t *pte_k;

		pgd_k = init_mm.pgd + index;

		if (!pgd_present(*pgd_k))
			goto no_context;

		pud_k = pud_offset(pgd_k, address);
		if (!pud_present(*pud_k))
			goto no_context;

		pmd_k = pmd_offset(pud_k, address);
		if (!pmd_present(*pmd_k))
			goto no_context;

		pgd = (pgd_t *) PTBR + index;
		pud = pud_offset(pgd, address);
		pmd = pmd_offset(pud, address);
		set_pmd(pmd, *pmd_k);

		pte_k = pte_offset_kernel(pmd_k, address);
		if (!pte_present(*pte_k))
			goto no_context;
		return;
	}
}
Commit	Line	Data
b920de1b DH	1	/* MN10300 MMU Fault handler
	2	*
	3	* Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
	4	* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
	5	* Modified by David Howells (dhowells@redhat.com)
	6	*
	7	* This program is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU General Public Licence
	9	* as published by the Free Software Foundation; either version
	10	* 2 of the Licence, or (at your option) any later version.
	11	*/
	12
	13	#include <linux/signal.h>
	14	#include <linux/sched.h>
	15	#include <linux/kernel.h>
	16	#include <linux/errno.h>
	17	#include <linux/string.h>
	18	#include <linux/types.h>
	19	#include <linux/ptrace.h>
	20	#include <linux/mman.h>
	21	#include <linux/mm.h>
	22	#include <linux/smp.h>
b920de1b DH	23	#include <linux/interrupt.h>
	24	#include <linux/init.h>
	25	#include <linux/vt_kern.h> /* For unblank_screen() */
	26
b920de1b DH	27	#include <asm/uaccess.h>
	28	#include <asm/pgalloc.h>
	29	#include <asm/hardirq.h>
b920de1b	30	#include <asm/cpu-regs.h>
67ddb405 DH	31	#include <asm/debugger.h>
67ddb405 DH	32	#include <asm/gdb-stub.h>
b920de1b DH	33
	34	/*
	35	* Unlock any spinlocks which will prevent us from getting the
	36	* message out
	37	*/
	38	void bust_spinlocks(int yes)
	39	{
	40	if (yes) {
	41	oops_in_progress = 1;
b920de1b DH	42	} else {
	43	int loglevel_save = console_loglevel;
	44	#ifdef CONFIG_VT
	45	unblank_screen();
	46	#endif
	47	oops_in_progress = 0;
	48	/*
	49	* OK, the message is on the console. Now we call printk()
	50	* without oops_in_progress set so that printk will give klogd
	51	* a poke. Hold onto your hats...
	52	*/
	53	console_loglevel = 15; /* NMI oopser may have shut the console
	54	* up */
	55	printk(" ");
	56	console_loglevel = loglevel_save;
	57	}
	58	}
	59
	60	void do_BUG(const char *file, int line)
	61	{
	62	bust_spinlocks(1);
	63	printk(KERN_EMERG "------------[ cut here ]------------\n");
	64	printk(KERN_EMERG "kernel BUG at %s:%d!\n", file, line);
	65	}
	66
	67	#if 0
	68	static void print_pagetable_entries(pgd_t *pgdir, unsigned long address)
	69	{
	70	pgd_t *pgd;
	71	pmd_t *pmd;
	72	pte_t *pte;
	73
	74	pgd = pgdir + __pgd_offset(address);
	75	printk(KERN_DEBUG "pgd entry %p: %016Lx\n",
	76	pgd, (long long) pgd_val(*pgd));
	77
	78	if (!pgd_present(*pgd)) {
	79	printk(KERN_DEBUG "... pgd not present!\n");
	80	return;
	81	}
	82	pmd = pmd_offset(pgd, address);
	83	printk(KERN_DEBUG "pmd entry %p: %016Lx\n",
	84	pmd, (long long)pmd_val(*pmd));
	85
	86	if (!pmd_present(*pmd)) {
	87	printk(KERN_DEBUG "... pmd not present!\n");
	88	return;
	89	}
	90	pte = pte_offset(pmd, address);
	91	printk(KERN_DEBUG "pte entry %p: %016Lx\n",
	92	pte, (long long) pte_val(*pte));
	93
	94	if (!pte_present(*pte))
	95	printk(KERN_DEBUG "... pte not present!\n");
	96	}
	97	#endif
	98
b920de1b DH	99	/*
	100	* This routine handles page faults. It determines the address,
	101	* and the problem, and then passes it off to one of the appropriate
	102	* routines.
	103	*
	104	* fault_code:
	105	* - LSW: either MMUFCR_IFC or MMUFCR_DFC as appropriate
	106	* - MSW: 0 if data access, 1 if instruction access
	107	* - bit 0: TLB miss flag
	108	* - bit 1: initial write
	109	* - bit 2: page invalid
	110	* - bit 3: protection violation
	111	* - bit 4: accessor (0=user 1=kernel)
	112	* - bit 5: 0=read 1=write
	113	* - bit 6-8: page protection spec
	114	* - bit 9: illegal address
	115	* - bit 16: 0=data 1=ins
	116	*
	117	*/
	118	asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code,
	119	unsigned long address)
	120	{
	121	struct vm_area_struct *vma;
	122	struct task_struct *tsk;
	123	struct mm_struct *mm;
	124	unsigned long page;
	125	siginfo_t info;
3d7b6a67 KC	126	int fault;
3d7b6a67 KC	127	unsigned int flags = FAULT_FLAG_ALLOW_RETRY \| FAULT_FLAG_KILLABLE;
b920de1b DH	128
	129	#ifdef CONFIG_GDBSTUB
	130	/* handle GDB stub causing a fault */
	131	if (gdbstub_busy) {
	132	gdbstub_exception(regs, TBR & TBR_INT_CODE);
	133	return;
	134	}
	135	#endif
	136
	137	#if 0
	138	printk(KERN_DEBUG "--- do_page_fault(%p,%s:%04lx,%08lx)\n",
	139	regs,
	140	fault_code & 0x10000 ? "ins" : "data",
	141	fault_code & 0xffff, address);
	142	#endif
	143
	144	tsk = current;
	145
	146	/*
	147	* We fault-in kernel-space virtual memory on-demand. The
	148	* 'reference' page table is init_mm.pgd.
	149	*
	150	* NOTE! We MUST NOT take any locks for this case. We may
	151	* be in an interrupt or a critical region, and should
	152	* only copy the information from the master page table,
	153	* nothing more.
	154	*
	155	* This verifies that the fault happens in kernel space
	156	* and that the fault was a page not present (invalid) error
	157	*/
	158	if (address >= VMALLOC_START && address < VMALLOC_END &&
	159	(fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR &&
	160	(fault_code & MMUFCR_xFC_PGINVAL) == MMUFCR_xFC_PGINVAL
	161	)
	162	goto vmalloc_fault;
	163
	164	mm = tsk->mm;
	165	info.si_code = SEGV_MAPERR;
	166
	167	/*
	168	* If we're in an interrupt or have no user
	169	* context, we must not take the fault..
	170	*/
d1c6d2e5	171	if (in_atomic() \|\| !mm)
b920de1b DH	172	goto no_context;
b920de1b DH	173
759496ba JW	174	if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR)
759496ba JW	175	flags \|= FAULT_FLAG_USER;
3d7b6a67	176	retry:
b920de1b DH	177	down_read(&mm->mmap_sem);
	178
	179	vma = find_vma(mm, address);
	180	if (!vma)
	181	goto bad_area;
	182	if (vma->vm_start <= address)
	183	goto good_area;
	184	if (!(vma->vm_flags & VM_GROWSDOWN))
	185	goto bad_area;
	186
	187	if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) {
	188	/* accessing the stack below the stack pointer is always a
	189	* bug */
	190	if ((address & PAGE_MASK) + 2 * PAGE_SIZE < regs->sp) {
	191	#if 0
	192	printk(KERN_WARNING
	193	"[%d] ### Access below stack @%lx (sp=%lx)\n",
	194	current->pid, address, regs->sp);
	195	printk(KERN_WARNING
	196	"vma [%08x - %08x]\n",
	197	vma->vm_start, vma->vm_end);
	198	show_registers(regs);
	199	printk(KERN_WARNING
	200	"[%d] ### Code: [%08lx]"
	201	" %02x %02x %02x %02x %02x %02x %02x %02x\n",
	202	current->pid,
	203	regs->pc,
	204	((u8 *) regs->pc)[0],
	205	((u8 *) regs->pc)[1],
	206	((u8 *) regs->pc)[2],
	207	((u8 *) regs->pc)[3],
	208	((u8 *) regs->pc)[4],
	209	((u8 *) regs->pc)[5],
	210	((u8 *) regs->pc)[6],
	211	((u8 *) regs->pc)[7]
	212	);
	213	#endif
	214	goto bad_area;
	215	}
	216	}
	217
	218	if (expand_stack(vma, address))
	219	goto bad_area;
	220
	221	/*
	222	* Ok, we have a good vm_area for this memory access, so
	223	* we can handle it..
	224	*/
	225	good_area:
	226	info.si_code = SEGV_ACCERR;
b920de1b DH	227	switch (fault_code & (MMUFCR_xFC_PGINVAL\|MMUFCR_xFC_TYPE)) {
	228	default: /* 3: write, present */
	229	case MMUFCR_xFC_TYPE_WRITE:
	230	#ifdef TEST_VERIFY_AREA
	231	if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR)
	232	printk(KERN_DEBUG "WP fault at %08lx\n", regs->pc);
	233	#endif
	234	/* write to absent page */
	235	case MMUFCR_xFC_PGINVAL \| MMUFCR_xFC_TYPE_WRITE:
	236	if (!(vma->vm_flags & VM_WRITE))
	237	goto bad_area;
3d7b6a67	238	flags \|= FAULT_FLAG_WRITE;
b920de1b DH	239	break;
	240
	241	/* read from protected page */
	242	case MMUFCR_xFC_TYPE_READ:
	243	goto bad_area;
	244
	245	/* read from absent page present */
	246	case MMUFCR_xFC_PGINVAL \| MMUFCR_xFC_TYPE_READ:
	247	if (!(vma->vm_flags & (VM_READ \| VM_EXEC)))
	248	goto bad_area;
	249	break;
	250	}
	251
	252	/*
	253	* If for any reason at all we couldn't handle the fault,
	254	* make sure we exit gracefully rather than endlessly redo
	255	* the fault.
	256	*/
3d7b6a67 KC	257	fault = handle_mm_fault(mm, vma, address, flags);
	258
	259	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
	260	return;
	261
b920de1b DH	262	if (unlikely(fault & VM_FAULT_ERROR)) {
	263	if (fault & VM_FAULT_OOM)
	264	goto out_of_memory;
	265	else if (fault & VM_FAULT_SIGBUS)
	266	goto do_sigbus;
	267	BUG();
	268	}
3d7b6a67 KC	269	if (flags & FAULT_FLAG_ALLOW_RETRY) {
	270	if (fault & VM_FAULT_MAJOR)
	271	current->maj_flt++;
	272	else
	273	current->min_flt++;
	274	if (fault & VM_FAULT_RETRY) {
	275	flags &= ~FAULT_FLAG_ALLOW_RETRY;
	276
	277	/* No need to up_read(&mm->mmap_sem) as we would
	278	* have already released it in __lock_page_or_retry
	279	* in mm/filemap.c.
	280	*/
	281
	282	goto retry;
	283	}
	284	}
b920de1b DH	285
	286	up_read(&mm->mmap_sem);
	287	return;
	288
	289	/*
	290	* Something tried to access memory that isn't in our memory map..
	291	* Fix it, but check if it's kernel or user first..
	292	*/
	293	bad_area:
	294	up_read(&mm->mmap_sem);
b920de1b DH	295
	296	/* User mode accesses just cause a SIGSEGV */
	297	if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) {
	298	info.si_signo = SIGSEGV;
	299	info.si_errno = 0;
	300	/* info.si_code has been set above */
	301	info.si_addr = (void *)address;
	302	force_sig_info(SIGSEGV, &info, tsk);
	303	return;
	304	}
	305
	306	no_context:
b920de1b DH	307	/* Are we prepared to handle this kernel fault? */
	308	if (fixup_exception(regs))
	309	return;
	310
	311	/*
	312	* Oops. The kernel tried to access some bad page. We'll have to
	313	* terminate things with extreme prejudice.
	314	*/
	315
	316	bust_spinlocks(1);
	317
	318	if (address < PAGE_SIZE)
	319	printk(KERN_ALERT
	320	"Unable to handle kernel NULL pointer dereference");
	321	else
	322	printk(KERN_ALERT
	323	"Unable to handle kernel paging request");
	324	printk(" at virtual address %08lx\n", address);
	325	printk(" printing pc:\n");
	326	printk(KERN_ALERT "%08lx\n", regs->pc);
	327
67ddb405 DH	328	debugger_intercept(fault_code & 0x00010000 ? EXCEP_IAERROR : EXCEP_DAERROR,
67ddb405 DH	329	SIGSEGV, SEGV_ACCERR, regs);
b920de1b DH	330
	331	page = PTBR;
	332	page = ((unsigned long *) __va(page))[address >> 22];
	333	printk(KERN_ALERT "*pde = %08lx\n", page);
	334	if (page & 1) {
	335	page &= PAGE_MASK;
	336	address &= 0x003ff000;
	337	page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT];
	338	printk(KERN_ALERT "*pte = %08lx\n", page);
	339	}
	340
	341	die("Oops", regs, fault_code);
	342	do_exit(SIGKILL);
	343
	344	/*
	345	* We ran out of memory, or some other thing happened to us that made
	346	* us unable to handle the page fault gracefully.
	347	*/
	348	out_of_memory:
	349	up_read(&mm->mmap_sem);
609838cf JW	350	if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR) {
	351	pagefault_out_of_memory();
	352	return;
	353	}
368dd5ac	354	goto no_context;
b920de1b DH	355
	356	do_sigbus:
	357	up_read(&mm->mmap_sem);
b920de1b DH	358
	359	/*
	360	* Send a sigbus, regardless of whether we were in kernel
	361	* or user mode.
	362	*/
	363	info.si_signo = SIGBUS;
	364	info.si_errno = 0;
	365	info.si_code = BUS_ADRERR;
	366	info.si_addr = (void *)address;
	367	force_sig_info(SIGBUS, &info, tsk);
	368
	369	/* Kernel mode? Handle exceptions or die */
	370	if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_SR)
	371	goto no_context;
	372	return;
	373
	374	vmalloc_fault:
	375	{
	376	/*
	377	* Synchronize this task's top level page-table
	378	* with the 'reference' page table.
	379	*
	380	* Do _not_ use "tsk" here. We might be inside
	381	* an interrupt in the middle of a task switch..
	382	*/
	383	int index = pgd_index(address);
	384	pgd_t pgd, pgd_k;
	385	pud_t pud, pud_k;
	386	pmd_t pmd, pmd_k;
	387	pte_t *pte_k;
	388
	389	pgd_k = init_mm.pgd + index;
	390
	391	if (!pgd_present(*pgd_k))
	392	goto no_context;
	393
	394	pud_k = pud_offset(pgd_k, address);
	395	if (!pud_present(*pud_k))
	396	goto no_context;
	397
	398	pmd_k = pmd_offset(pud_k, address);
	399	if (!pmd_present(*pmd_k))
	400	goto no_context;
	401
	402	pgd = (pgd_t *) PTBR + index;
	403	pud = pud_offset(pgd, address);
	404	pmd = pmd_offset(pud, address);
	405	set_pmd(pmd, *pmd_k);
	406
	407	pte_k = pte_offset_kernel(pmd_k, address);
	408	if (!pte_present(*pte_k))
	409	goto no_context;
	410	return;
	411	}
	412	}