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

/*
 * 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);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* This file is subject to the terms and conditions of the GNU General Public
	3	* License. See the file "COPYING" in the main directory of this archive
	4	* for more details.
	5	*
	6	* Copyright (C) 1995 - 2000 by Ralf Baechle
	7	*/
c3fc5cd5	8	#include <linux/context_tracking.h>
1da177e4 LT	9	#include <linux/signal.h>
	10	#include <linux/sched.h>
	11	#include <linux/interrupt.h>
	12	#include <linux/kernel.h>
	13	#include <linux/errno.h>
	14	#include <linux/string.h>
	15	#include <linux/types.h>
	16	#include <linux/ptrace.h>
d79d853d	17	#include <linux/ratelimit.h>
1da177e4 LT	18	#include <linux/mman.h>
	19	#include <linux/mm.h>
	20	#include <linux/smp.h>
1da177e4	21	#include <linux/module.h>
c1bf207d	22	#include <linux/kprobes.h>
7f788d2d	23	#include <linux/perf_event.h>
70ffdb93	24	#include <linux/uaccess.h>
1da177e4 LT	25
	26	#include <asm/branch.h>
	27	#include <asm/mmu_context.h>
1da177e4	28	#include <asm/ptrace.h>
16033d61	29	#include <asm/highmem.h> /* For VMALLOC_END */
c1bf207d	30	#include <linux/kdebug.h>
1da177e4	31
d79d853d MC	32	int show_unhandled_signals = 1;
d79d853d MC	33
1da177e4 LT	34	/*
	35	* This routine handles page faults. It determines the address,
	36	* and the problem, and then passes it off to one of the appropriate
	37	* routines.
	38	*/
c3fc5cd5 RB	39	static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write,
c3fc5cd5 RB	40	unsigned long address)
1da177e4 LT	41	{
	42	struct vm_area_struct * vma = NULL;
	43	struct task_struct *tsk = current;
	44	struct mm_struct *mm = tsk->mm;
	45	const int field = sizeof(unsigned long) * 2;
	46	siginfo_t info;
83c54070	47	int fault;
759496ba	48	unsigned int flags = FAULT_FLAG_ALLOW_RETRY \| FAULT_FLAG_KILLABLE;
1da177e4	49
d79d853d MC	50	static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
d79d853d MC	51
1da177e4	52	#if 0
d6f70360	53	printk("Cpu%d[%s:%d:%0lx:%ld:%0lx]\n", raw_smp_processor_id(),
1da177e4 LT	54	current->comm, current->pid, field, address, write,
	55	field, regs->cp0_epc);
	56	#endif
	57
c1bf207d DD	58	#ifdef CONFIG_KPROBES
c1bf207d DD	59	/*
70342287	60	* This is to notify the fault handler of the kprobes. The
c1bf207d DD	61	* exception code is redundant as it is also carried in REGS,
	62	* but we pass it anyhow.
	63	*/
	64	if (notify_die(DIE_PAGE_FAULT, "page fault", regs, -1,
	65	(regs->cp0_cause >> 2) & 0x1f, SIGSEGV) == NOTIFY_STOP)
	66	return;
	67	#endif
	68
1da177e4 LT	69	info.si_code = SEGV_MAPERR;
	70
	71	/*
	72	* We fault-in kernel-space virtual memory on-demand. The
	73	* 'reference' page table is init_mm.pgd.
	74	*
	75	* NOTE! We MUST NOT take any locks for this case. We may
	76	* be in an interrupt or a critical region, and should
	77	* only copy the information from the master page table,
	78	* nothing more.
	79	*/
2ca2ebfd DD	80	#ifdef CONFIG_64BIT
	81	# define VMALLOC_FAULT_TARGET no_context
	82	#else
	83	# define VMALLOC_FAULT_TARGET vmalloc_fault
	84	#endif
	85
16033d61	86	if (unlikely(address >= VMALLOC_START && address <= VMALLOC_END))
2ca2ebfd	87	goto VMALLOC_FAULT_TARGET;
656be92f AN	88	#ifdef MODULE_START
656be92f AN	89	if (unlikely(address >= MODULE_START && address < MODULE_END))
2ca2ebfd	90	goto VMALLOC_FAULT_TARGET;
656be92f	91	#endif
1da177e4 LT	92
	93	/*
	94	* If we're in an interrupt or have no user
	95	* context, we must not take the fault..
	96	*/
70ffdb93	97	if (faulthandler_disabled() \|\| !mm)
1da177e4 LT	98	goto bad_area_nosemaphore;
1da177e4 LT	99
759496ba JW	100	if (user_mode(regs))
759496ba JW	101	flags \|= FAULT_FLAG_USER;
43ca4957	102	retry:
1da177e4 LT	103	down_read(&mm->mmap_sem);
	104	vma = find_vma(mm, address);
	105	if (!vma)
	106	goto bad_area;
	107	if (vma->vm_start <= address)
	108	goto good_area;
	109	if (!(vma->vm_flags & VM_GROWSDOWN))
	110	goto bad_area;
	111	if (expand_stack(vma, address))
	112	goto bad_area;
	113	/*
	114	* Ok, we have a good vm_area for this memory access, so
	115	* we can handle it..
	116	*/
	117	good_area:
	118	info.si_code = SEGV_ACCERR;
	119
	120	if (write) {
	121	if (!(vma->vm_flags & VM_WRITE))
	122	goto bad_area;
759496ba	123	flags \|= FAULT_FLAG_WRITE;
1da177e4	124	} else {
05857c64	125	if (cpu_has_rixi) {
6dd9344c DD	126	if (address == regs->cp0_epc && !(vma->vm_flags & VM_EXEC)) {
	127	#if 0
	128	pr_notice("Cpu%d[%s:%d:%0lx:%ld:%0lx] XI violation\n",
	129	raw_smp_processor_id(),
	130	current->comm, current->pid,
	131	field, address, write,
	132	field, regs->cp0_epc);
	133	#endif
	134	goto bad_area;
	135	}
	136	if (!(vma->vm_flags & VM_READ)) {
	137	#if 0
	138	pr_notice("Cpu%d[%s:%d:%0lx:%ld:%0lx] RI violation\n",
	139	raw_smp_processor_id(),
	140	current->comm, current->pid,
	141	field, address, write,
	142	field, regs->cp0_epc);
	143	#endif
	144	goto bad_area;
	145	}
	146	} else {
	147	if (!(vma->vm_flags & (VM_READ \| VM_WRITE \| VM_EXEC)))
	148	goto bad_area;
	149	}
1da177e4 LT	150	}
1da177e4 LT	151
1da177e4 LT	152	/*
	153	* If for any reason at all we couldn't handle the fault,
	154	* make sure we exit gracefully rather than endlessly redo
	155	* the fault.
	156	*/
43ca4957 KC	157	fault = handle_mm_fault(mm, vma, address, flags);
	158
	159	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
	160	return;
	161
a8b0ca17	162	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
83c54070 NP	163	if (unlikely(fault & VM_FAULT_ERROR)) {
	164	if (fault & VM_FAULT_OOM)
	165	goto out_of_memory;
33692f27 LT	166	else if (fault & VM_FAULT_SIGSEGV)
33692f27 LT	167	goto bad_area;
83c54070 NP	168	else if (fault & VM_FAULT_SIGBUS)
83c54070 NP	169	goto do_sigbus;
1da177e4 LT	170	BUG();
1da177e4 LT	171	}
43ca4957 KC	172	if (flags & FAULT_FLAG_ALLOW_RETRY) {
	173	if (fault & VM_FAULT_MAJOR) {
	174	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
	175	regs, address);
	176	tsk->maj_flt++;
	177	} else {
	178	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
	179	regs, address);
	180	tsk->min_flt++;
	181	}
	182	if (fault & VM_FAULT_RETRY) {
	183	flags &= ~FAULT_FLAG_ALLOW_RETRY;
45cac65b	184	flags \|= FAULT_FLAG_TRIED;
43ca4957 KC	185
	186	/*
	187	* No need to up_read(&mm->mmap_sem) as we would
	188	* have already released it in __lock_page_or_retry
	189	* in mm/filemap.c.
	190	*/
	191
	192	goto retry;
	193	}
7f788d2d	194	}
1da177e4 LT	195
	196	up_read(&mm->mmap_sem);
	197	return;
	198
	199	/*
	200	* Something tried to access memory that isn't in our memory map..
	201	* Fix it, but check if it's kernel or user first..
	202	*/
	203	bad_area:
	204	up_read(&mm->mmap_sem);
	205
	206	bad_area_nosemaphore:
	207	/* User mode accesses just cause a SIGSEGV */
	208	if (user_mode(regs)) {
	209	tsk->thread.cp0_badvaddr = address;
	210	tsk->thread.error_code = write;
d79d853d MC	211	if (show_unhandled_signals &&
	212	unhandled_signal(tsk, SIGSEGV) &&
	213	__ratelimit(&ratelimit_state)) {
	214	pr_info("\ndo_page_fault(): sending SIGSEGV to %s for invalid %s %0*lx",
	215	tsk->comm,
	216	write ? "write access to" : "read access from",
	217	field, address);
	218	pr_info("epc = %0*lx in", field,
	219	(unsigned long) regs->cp0_epc);
	220	print_vma_addr(" ", regs->cp0_epc);
	221	pr_info("ra = %0*lx in", field,
	222	(unsigned long) regs->regs[31]);
	223	print_vma_addr(" ", regs->regs[31]);
	224	pr_info("\n");
	225	}
1da177e4 LT	226	info.si_signo = SIGSEGV;
	227	info.si_errno = 0;
	228	/* info.si_code has been set above */
fe00f943	229	info.si_addr = (void __user *) address;
1da177e4 LT	230	force_sig_info(SIGSEGV, &info, tsk);
	231	return;
	232	}
	233
	234	no_context:
70342287	235	/* Are we prepared to handle this kernel fault? */
1da177e4 LT	236	if (fixup_exception(regs)) {
	237	current->thread.cp0_baduaddr = address;
	238	return;
	239	}
	240
	241	/*
	242	* Oops. The kernel tried to access some bad page. We'll have to
	243	* terminate things with extreme prejudice.
	244	*/
1da177e4 LT	245	bust_spinlocks(1);
	246
	247	printk(KERN_ALERT "CPU %d Unable to handle kernel paging request at "
	248	"virtual address %0lx, epc == %0lx, ra == %0*lx\n",
d6f70360	249	raw_smp_processor_id(), field, address, field, regs->cp0_epc,
1da177e4 LT	250	field, regs->regs[31]);
	251	die("Oops", regs);
	252
1da177e4	253	out_of_memory:
c7c1e384 RB	254	/*
	255	* We ran out of memory, call the OOM killer, and return the userspace
	256	* (which will retry the fault, or kill us if we got oom-killed).
	257	*/
a887b4da	258	up_read(&mm->mmap_sem);
87134102 JW	259	if (!user_mode(regs))
87134102 JW	260	goto no_context;
c7c1e384 RB	261	pagefault_out_of_memory();
c7c1e384 RB	262	return;
1da177e4 LT	263
	264	do_sigbus:
	265	up_read(&mm->mmap_sem);
	266
	267	/* Kernel mode? Handle exceptions or die */
	268	if (!user_mode(regs))
	269	goto no_context;
41c594ab	270	else
1da177e4 LT	271	/*
	272	* Send a sigbus, regardless of whether we were in kernel
	273	* or user mode.
	274	*/
41c594ab RB	275	#if 0
	276	printk("do_page_fault() #3: sending SIGBUS to %s for "
	277	"invalid %s\n%0lx (epc == %0lx, ra == %0*lx)\n",
	278	tsk->comm,
	279	write ? "write access to" : "read access from",
	280	field, address,
	281	field, (unsigned long) regs->cp0_epc,
	282	field, (unsigned long) regs->regs[31]);
	283	#endif
1da177e4 LT	284	tsk->thread.cp0_badvaddr = address;
	285	info.si_signo = SIGBUS;
	286	info.si_errno = 0;
	287	info.si_code = BUS_ADRERR;
fe00f943	288	info.si_addr = (void __user *) address;
1da177e4 LT	289	force_sig_info(SIGBUS, &info, tsk);
	290
	291	return;
2ca2ebfd	292	#ifndef CONFIG_64BIT
1da177e4 LT	293	vmalloc_fault:
	294	{
	295	/*
	296	* Synchronize this task's top level page-table
	297	* with the 'reference' page table.
	298	*
	299	* Do _not_ use "tsk" here. We might be inside
	300	* an interrupt in the middle of a task switch..
	301	*/
	302	int offset = __pgd_offset(address);
	303	pgd_t pgd, pgd_k;
c6e8b587	304	pud_t pud, pud_k;
1da177e4 LT	305	pmd_t pmd, pmd_k;
	306	pte_t *pte_k;
	307
d6f70360	308	pgd = (pgd_t *) pgd_current[raw_smp_processor_id()] + offset;
1da177e4 LT	309	pgd_k = init_mm.pgd + offset;
	310
	311	if (!pgd_present(*pgd_k))
	312	goto no_context;
	313	set_pgd(pgd, *pgd_k);
	314
c6e8b587 RB	315	pud = pud_offset(pgd, address);
	316	pud_k = pud_offset(pgd_k, address);
	317	if (!pud_present(*pud_k))
	318	goto no_context;
	319
	320	pmd = pmd_offset(pud, address);
	321	pmd_k = pmd_offset(pud_k, address);
1da177e4 LT	322	if (!pmd_present(*pmd_k))
	323	goto no_context;
	324	set_pmd(pmd, *pmd_k);
	325
	326	pte_k = pte_offset_kernel(pmd_k, address);
	327	if (!pte_present(*pte_k))
	328	goto no_context;
	329	return;
	330	}
2ca2ebfd	331	#endif
1da177e4	332	}
c3fc5cd5 RB	333
	334	asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
	335	unsigned long write, unsigned long address)
	336	{
	337	enum ctx_state prev_state;
	338
	339	prev_state = exception_enter();
	340	__do_page_fault(regs, write, address);
	341	exception_exit(prev_state);
	342	}