[deliverable/linux.git] / arch / sh / mm / fault.c

/*
 * Page fault handler for SH with an MMU.
 *
 *  Copyright (C) 1999  Niibe Yutaka
 *  Copyright (C) 2003 - 2007  Paul Mundt
 *
 *  Based on linux/arch/i386/mm/fault.c:
 *   Copyright (C) 1995  Linus Torvalds
 *
 * 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.
 */
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/hardirq.h>
#include <linux/kprobes.h>
#include <asm/system.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
#include <asm/kgdb.h>

/*
 * 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 __kprobes do_page_fault(struct pt_regs *regs,
					unsigned long writeaccess,
					unsigned long address)
{
	struct task_struct *tsk;
	struct mm_struct *mm;
	struct vm_area_struct * vma;
	int si_code;
	int fault;
	siginfo_t info;

	trace_hardirqs_on();
	local_irq_enable();

#ifdef CONFIG_SH_KGDB
	if (kgdb_nofault && kgdb_bus_err_hook)
		kgdb_bus_err_hook();
#endif

	tsk = current;
	mm = tsk->mm;
	si_code = SEGV_MAPERR;

	if (unlikely(address >= TASK_SIZE)) {
		/*
		 * 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_index(address);
		pgd_t *pgd, *pgd_k;
		pud_t *pud, *pud_k;
		pmd_t *pmd, *pmd_k;

		pgd = get_TTB() + offset;
		pgd_k = swapper_pg_dir + offset;

		/* This will never happen with the folded page table. */
		if (!pgd_present(*pgd)) {
			if (!pgd_present(*pgd_k))
				goto bad_area_nosemaphore;
			set_pgd(pgd, *pgd_k);
			return;
		}

		pud = pud_offset(pgd, address);
		pud_k = pud_offset(pgd_k, address);
		if (pud_present(*pud) || !pud_present(*pud_k))
			goto bad_area_nosemaphore;
		set_pud(pud, *pud_k);

		pmd = pmd_offset(pud, address);
		pmd_k = pmd_offset(pud_k, address);
		if (pmd_present(*pmd) || !pmd_present(*pmd_k))
			goto bad_area_nosemaphore;
		set_pmd(pmd, *pmd_k);

		return;
	}

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

	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:
	si_code = SEGV_ACCERR;
	if (writeaccess) {
		if (!(vma->vm_flags & VM_WRITE))
			goto bad_area;
	} else {
		if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
			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:
	fault = handle_mm_fault(mm, vma, address, writeaccess);
	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 (fault & VM_FAULT_MAJOR)
		tsk->maj_flt++;
	else
		tsk->min_flt++;

	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:
	if (user_mode(regs)) {
		info.si_signo = SIGSEGV;
		info.si_errno = 0;
		info.si_code = si_code;
		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 (oops_may_print()) {
		__typeof__(pte_val(__pte(0))) page;

		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\n", regs->pc);
		page = (unsigned long)get_TTB();
		if (page) {
			page = ((__typeof__(page) *) __va(page))[address >>
								 PGDIR_SHIFT];
			printk(KERN_ALERT "*pde = %08lx\n", page);
			if (page & _PAGE_PRESENT) {
				page &= PAGE_MASK;
				address &= 0x003ff000;
				page = ((__typeof__(page) *)
						__va(page))[address >>
							    PAGE_SHIFT];
				printk(KERN_ALERT "*pte = %08lx\n", page);
			}
		}
	}

	die("Oops", regs, writeaccess);
	bust_spinlocks(0);
	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 (is_init(current)) {
		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:
	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 (!user_mode(regs))
		goto no_context;
}

#ifdef CONFIG_SH_STORE_QUEUES
/*
 * This is a special case for the SH-4 store queues, as pages for this
 * space still need to be faulted in before it's possible to flush the
 * store queue cache for writeout to the remapped region.
 */
#define P3_ADDR_MAX		(P4SEG_STORE_QUE + 0x04000000)
#else
#define P3_ADDR_MAX		P4SEG
#endif

/*
 * Called with interrupts disabled.
 */
asmlinkage int __kprobes __do_page_fault(struct pt_regs *regs,
					 unsigned long writeaccess,
					 unsigned long address)
{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;
	pte_t entry;
	struct mm_struct *mm = current->mm;
	spinlock_t *ptl = NULL;
	int ret = 1;

#ifdef CONFIG_SH_KGDB
	if (kgdb_nofault && kgdb_bus_err_hook)
		kgdb_bus_err_hook();
#endif

	/*
	 * We don't take page faults for P1, P2, and parts of P4, these
	 * are always mapped, whether it be due to legacy behaviour in
	 * 29-bit mode, or due to PMB configuration in 32-bit mode.
	 */
	if (address >= P3SEG && address < P3_ADDR_MAX) {
		pgd = pgd_offset_k(address);
		mm = NULL;
	} else {
		if (unlikely(address >= TASK_SIZE || !mm))
			return 1;

		pgd = pgd_offset(mm, address);
	}

	pud = pud_offset(pgd, address);
	if (pud_none_or_clear_bad(pud))
		return 1;
	pmd = pmd_offset(pud, address);
	if (pmd_none_or_clear_bad(pmd))
		return 1;

	if (mm)
		pte = pte_offset_map_lock(mm, pmd, address, &ptl);
	else
		pte = pte_offset_kernel(pmd, address);

	entry = *pte;
	if (unlikely(pte_none(entry) || pte_not_present(entry)))
		goto unlock;
	if (unlikely(writeaccess && !pte_write(entry)))
		goto unlock;

	if (writeaccess)
		entry = pte_mkdirty(entry);
	entry = pte_mkyoung(entry);

#ifdef CONFIG_CPU_SH4
	/*
	 * ITLB is not affected by "ldtlb" instruction.
	 * So, we need to flush the entry by ourselves.
	 */
	local_flush_tlb_one(get_asid(), address & PAGE_MASK);
#endif

	set_pte(pte, entry);
	update_mmu_cache(NULL, address, entry);
	ret = 0;
unlock:
	if (mm)
		pte_unmap_unlock(pte, ptl);
	return ret;
}
Commit	Line	Data
26ff6c11 PM	1	/*
26ff6c11 PM	2	* Page fault handler for SH with an MMU.
1da177e4	3	*
1da177e4	4	* Copyright (C) 1999 Niibe Yutaka
3a2e117e	5	* Copyright (C) 2003 - 2007 Paul Mundt
1da177e4 LT	6	*
	7	* Based on linux/arch/i386/mm/fault.c:
	8	* Copyright (C) 1995 Linus Torvalds
26ff6c11 PM	9	*
	10	* This file is subject to the terms and conditions of the GNU General Public
	11	* License. See the file "COPYING" in the main directory of this archive
	12	* for more details.
1da177e4	13	*/
1da177e4	14	#include <linux/kernel.h>
1da177e4	15	#include <linux/mm.h>
0f08f338 PM	16	#include <linux/hardirq.h>
0f08f338 PM	17	#include <linux/kprobes.h>
1da177e4	18	#include <asm/system.h>
1da177e4	19	#include <asm/mmu_context.h>
db2e1fa3	20	#include <asm/tlbflush.h>
1da177e4 LT	21	#include <asm/kgdb.h>
1da177e4 LT	22
1da177e4 LT	23	/*
	24	* This routine handles page faults. It determines the address,
	25	* and the problem, and then passes it off to one of the appropriate
	26	* routines.
	27	*/
b5a1bcbe SM	28	asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
	29	unsigned long writeaccess,
	30	unsigned long address)
1da177e4 LT	31	{
	32	struct task_struct *tsk;
	33	struct mm_struct *mm;
	34	struct vm_area_struct * vma;
b5a1bcbe	35	int si_code;
83c54070	36	int fault;
b5a1bcbe	37	siginfo_t info;
1da177e4	38
afbfb52e PM	39	trace_hardirqs_on();
	40	local_irq_enable();
	41
1da177e4 LT	42	#ifdef CONFIG_SH_KGDB
	43	if (kgdb_nofault && kgdb_bus_err_hook)
	44	kgdb_bus_err_hook();
	45	#endif
	46
	47	tsk = current;
	48	mm = tsk->mm;
b5a1bcbe	49	si_code = SEGV_MAPERR;
1da177e4	50
99a596f9 SM	51	if (unlikely(address >= TASK_SIZE)) {
	52	/*
	53	* Synchronize this task's top level page-table
	54	* with the 'reference' page table.
	55	*
	56	* Do _not_ use "tsk" here. We might be inside
	57	* an interrupt in the middle of a task switch..
	58	*/
	59	int offset = pgd_index(address);
	60	pgd_t pgd, pgd_k;
	61	pud_t pud, pud_k;
	62	pmd_t pmd, pmd_k;
	63
	64	pgd = get_TTB() + offset;
	65	pgd_k = swapper_pg_dir + offset;
	66
	67	/* This will never happen with the folded page table. */
	68	if (!pgd_present(*pgd)) {
	69	if (!pgd_present(*pgd_k))
	70	goto bad_area_nosemaphore;
	71	set_pgd(pgd, *pgd_k);
	72	return;
	73	}
	74
	75	pud = pud_offset(pgd, address);
	76	pud_k = pud_offset(pgd_k, address);
	77	if (pud_present(pud) \|\| !pud_present(pud_k))
	78	goto bad_area_nosemaphore;
	79	set_pud(pud, *pud_k);
	80
	81	pmd = pmd_offset(pud, address);
	82	pmd_k = pmd_offset(pud_k, address);
	83	if (pmd_present(pmd) \|\| !pmd_present(pmd_k))
	84	goto bad_area_nosemaphore;
	85	set_pmd(pmd, *pmd_k);
	86
	87	return;
	88	}
	89
1da177e4 LT	90	/*
	91	* If we're in an interrupt or have no user
	92	* context, we must not take the fault..
	93	*/
	94	if (in_atomic() \|\| !mm)
	95	goto no_context;
	96
	97	down_read(&mm->mmap_sem);
	98
	99	vma = find_vma(mm, address);
	100	if (!vma)
	101	goto bad_area;
	102	if (vma->vm_start <= address)
	103	goto good_area;
	104	if (!(vma->vm_flags & VM_GROWSDOWN))
	105	goto bad_area;
	106	if (expand_stack(vma, address))
	107	goto bad_area;
	108	/*
	109	* Ok, we have a good vm_area for this memory access, so
	110	* we can handle it..
	111	*/
	112	good_area:
b5a1bcbe	113	si_code = SEGV_ACCERR;
1da177e4 LT	114	if (writeaccess) {
	115	if (!(vma->vm_flags & VM_WRITE))
	116	goto bad_area;
	117	} else {
df67b3da	118	if (!(vma->vm_flags & (VM_READ \| VM_EXEC \| VM_WRITE)))
1da177e4 LT	119	goto bad_area;
	120	}
	121
	122	/*
	123	* If for any reason at all we couldn't handle the fault,
	124	* make sure we exit gracefully rather than endlessly redo
	125	* the fault.
	126	*/
	127	survive:
83c54070 NP	128	fault = handle_mm_fault(mm, vma, address, writeaccess);
	129	if (unlikely(fault & VM_FAULT_ERROR)) {
	130	if (fault & VM_FAULT_OOM)
1da177e4	131	goto out_of_memory;
83c54070 NP	132	else if (fault & VM_FAULT_SIGBUS)
	133	goto do_sigbus;
	134	BUG();
1da177e4	135	}
83c54070 NP	136	if (fault & VM_FAULT_MAJOR)
	137	tsk->maj_flt++;
	138	else
	139	tsk->min_flt++;
1da177e4 LT	140
	141	up_read(&mm->mmap_sem);
	142	return;
	143
	144	/*
	145	* Something tried to access memory that isn't in our memory map..
	146	* Fix it, but check if it's kernel or user first..
	147	*/
	148	bad_area:
	149	up_read(&mm->mmap_sem);
	150
99a596f9	151	bad_area_nosemaphore:
1da177e4	152	if (user_mode(regs)) {
b5a1bcbe SM	153	info.si_signo = SIGSEGV;
	154	info.si_errno = 0;
	155	info.si_code = si_code;
	156	info.si_addr = (void *) address;
	157	force_sig_info(SIGSEGV, &info, tsk);
1da177e4 LT	158	return;
	159	}
	160
	161	no_context:
	162	/* Are we prepared to handle this kernel fault? */
	163	if (fixup_exception(regs))
	164	return;
	165
	166	/*
	167	* Oops. The kernel tried to access some bad page. We'll have to
	168	* terminate things with extreme prejudice.
	169	*
	170	*/
0630e45c PM	171
	172	bust_spinlocks(1);
	173
	174	if (oops_may_print()) {
	175	__typeof__(pte_val(__pte(0))) page;
	176
	177	if (address < PAGE_SIZE)
	178	printk(KERN_ALERT "Unable to handle kernel NULL "
	179	"pointer dereference");
	180	else
	181	printk(KERN_ALERT "Unable to handle kernel paging "
	182	"request");
	183	printk(" at virtual address %08lx\n", address);
	184	printk(KERN_ALERT "pc = %08lx\n", regs->pc);
	185	page = (unsigned long)get_TTB();
	186	if (page) {
	187	page = ((__typeof__(page) *) __va(page))[address >>
	188	PGDIR_SHIFT];
	189	printk(KERN_ALERT "*pde = %08lx\n", page);
	190	if (page & _PAGE_PRESENT) {
	191	page &= PAGE_MASK;
	192	address &= 0x003ff000;
	193	page = ((__typeof__(page) *)
	194	__va(page))[address >>
	195	PAGE_SHIFT];
	196	printk(KERN_ALERT "*pte = %08lx\n", page);
	197	}
1da177e4 LT	198	}
1da177e4 LT	199	}
0630e45c	200
1da177e4	201	die("Oops", regs, writeaccess);
0630e45c	202	bust_spinlocks(0);
1da177e4 LT	203	do_exit(SIGKILL);
	204
	205	/*
	206	* We ran out of memory, or some other thing happened to us that made
	207	* us unable to handle the page fault gracefully.
	208	*/
	209	out_of_memory:
	210	up_read(&mm->mmap_sem);
f400e198	211	if (is_init(current)) {
1da177e4 LT	212	yield();
	213	down_read(&mm->mmap_sem);
	214	goto survive;
	215	}
	216	printk("VM: killing process %s\n", tsk->comm);
	217	if (user_mode(regs))
	218	do_exit(SIGKILL);
	219	goto no_context;
	220
	221	do_sigbus:
	222	up_read(&mm->mmap_sem);
	223
	224	/*
	225	* Send a sigbus, regardless of whether we were in kernel
	226	* or user mode.
	227	*/
b5a1bcbe SM	228	info.si_signo = SIGBUS;
	229	info.si_errno = 0;
	230	info.si_code = BUS_ADRERR;
	231	info.si_addr = (void *)address;
	232	force_sig_info(SIGBUS, &info, tsk);
1da177e4 LT	233
	234	/* Kernel mode? Handle exceptions or die */
	235	if (!user_mode(regs))
	236	goto no_context;
	237	}
db2e1fa3 PM	238
	239	#ifdef CONFIG_SH_STORE_QUEUES
	240	/*
	241	* This is a special case for the SH-4 store queues, as pages for this
	242	* space still need to be faulted in before it's possible to flush the
	243	* store queue cache for writeout to the remapped region.
	244	*/
	245	#define P3_ADDR_MAX (P4SEG_STORE_QUE + 0x04000000)
	246	#else
	247	#define P3_ADDR_MAX P4SEG
	248	#endif
	249
	250	/*
	251	* Called with interrupts disabled.
	252	*/
	253	asmlinkage int __kprobes __do_page_fault(struct pt_regs *regs,
	254	unsigned long writeaccess,
	255	unsigned long address)
	256	{
	257	pgd_t *pgd;
	258	pud_t *pud;
	259	pmd_t *pmd;
	260	pte_t *pte;
	261	pte_t entry;
	262	struct mm_struct *mm = current->mm;
b8947444	263	spinlock_t *ptl = NULL;
db2e1fa3 PM	264	int ret = 1;
	265
	266	#ifdef CONFIG_SH_KGDB
	267	if (kgdb_nofault && kgdb_bus_err_hook)
	268	kgdb_bus_err_hook();
	269	#endif
	270
	271	/*
	272	* We don't take page faults for P1, P2, and parts of P4, these
	273	* are always mapped, whether it be due to legacy behaviour in
	274	* 29-bit mode, or due to PMB configuration in 32-bit mode.
	275	*/
	276	if (address >= P3SEG && address < P3_ADDR_MAX) {
	277	pgd = pgd_offset_k(address);
	278	mm = NULL;
	279	} else {
	280	if (unlikely(address >= TASK_SIZE \|\| !mm))
	281	return 1;
	282
	283	pgd = pgd_offset(mm, address);
	284	}
	285
	286	pud = pud_offset(pgd, address);
	287	if (pud_none_or_clear_bad(pud))
	288	return 1;
	289	pmd = pmd_offset(pud, address);
	290	if (pmd_none_or_clear_bad(pmd))
	291	return 1;
	292
	293	if (mm)
	294	pte = pte_offset_map_lock(mm, pmd, address, &ptl);
	295	else
	296	pte = pte_offset_kernel(pmd, address);
	297
	298	entry = *pte;
	299	if (unlikely(pte_none(entry) \|\| pte_not_present(entry)))
	300	goto unlock;
	301	if (unlikely(writeaccess && !pte_write(entry)))
	302	goto unlock;
	303
	304	if (writeaccess)
	305	entry = pte_mkdirty(entry);
	306	entry = pte_mkyoung(entry);
	307
	308	#ifdef CONFIG_CPU_SH4
	309	/*
	310	* ITLB is not affected by "ldtlb" instruction.
	311	* So, we need to flush the entry by ourselves.
	312	*/
	313	local_flush_tlb_one(get_asid(), address & PAGE_MASK);
	314	#endif
	315
	316	set_pte(pte, entry);
	317	update_mmu_cache(NULL, address, entry);
	318	ret = 0;
	319	unlock:
	320	if (mm)
	321	pte_unmap_unlock(pte, ptl);
	322	return ret;
	323	}