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

/*
 * Page fault handler for SH with an MMU.
 *
 *  Copyright (C) 1999  Niibe Yutaka
 *  Copyright (C) 2003  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/kgdb.h>

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

/*
 * 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 address)
{
	struct task_struct *tsk;
	struct mm_struct *mm;
	struct vm_area_struct * vma;
	unsigned long page;

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

	tsk = current;
	mm = tsk->mm;

	/*
	 * 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:
	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:
	switch (handle_mm_fault(mm, vma, address, writeaccess)) {
		case VM_FAULT_MINOR:
			tsk->min_flt++;
			break;
		case VM_FAULT_MAJOR:
			tsk->maj_flt++;
			break;
		case VM_FAULT_SIGBUS:
			goto do_sigbus;
		case VM_FAULT_OOM:
			goto out_of_memory;
		default:
			BUG();
	}

	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);

	if (user_mode(regs)) {
		tsk->thread.address = address;
		tsk->thread.error_code = writeaccess;
		force_sig(SIGSEGV, 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.
 *
 */
	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);
	asm volatile("mov.l	%1, %0"
		     : "=r" (page)
		     : "m" (__m(MMU_TTB)));
	if (page) {
		page = ((unsigned long *) page)[address >> 22];
		printk(KERN_ALERT "*pde = %08lx\n", page);
		if (page & _PAGE_PRESENT) {
			page &= PAGE_MASK;
			address &= 0x003ff000;
			page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT];
			printk(KERN_ALERT "*pte = %08lx\n", page);
		}
	}
	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:
	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.
	 */
	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;
}

#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;
	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.
	 */
	__flush_tlb_page(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 LT	4	* Copyright (C) 1999 Niibe Yutaka
	5	* Copyright (C) 2003 Paul Mundt
	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>
1da177e4 LT	20	#include <asm/kgdb.h>
	21
	22	extern void die(const char ,struct pt_regs ,long);
	23
	24	/*
	25	* This routine handles page faults. It determines the address,
	26	* and the problem, and then passes it off to one of the appropriate
	27	* routines.
	28	*/
	29	asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long writeaccess,
	30	unsigned long address)
	31	{
	32	struct task_struct *tsk;
	33	struct mm_struct *mm;
	34	struct vm_area_struct * vma;
	35	unsigned long page;
	36
	37	#ifdef CONFIG_SH_KGDB
	38	if (kgdb_nofault && kgdb_bus_err_hook)
	39	kgdb_bus_err_hook();
	40	#endif
	41
	42	tsk = current;
	43	mm = tsk->mm;
	44
	45	/*
	46	* If we're in an interrupt or have no user
	47	* context, we must not take the fault..
	48	*/
	49	if (in_atomic() \|\| !mm)
	50	goto no_context;
	51
	52	down_read(&mm->mmap_sem);
	53
	54	vma = find_vma(mm, address);
	55	if (!vma)
	56	goto bad_area;
	57	if (vma->vm_start <= address)
	58	goto good_area;
	59	if (!(vma->vm_flags & VM_GROWSDOWN))
	60	goto bad_area;
	61	if (expand_stack(vma, address))
	62	goto bad_area;
	63	/*
	64	* Ok, we have a good vm_area for this memory access, so
	65	* we can handle it..
	66	*/
	67	good_area:
	68	if (writeaccess) {
	69	if (!(vma->vm_flags & VM_WRITE))
	70	goto bad_area;
	71	} else {
df67b3da	72	if (!(vma->vm_flags & (VM_READ \| VM_EXEC \| VM_WRITE)))
1da177e4 LT	73	goto bad_area;
	74	}
	75
	76	/*
	77	* If for any reason at all we couldn't handle the fault,
	78	* make sure we exit gracefully rather than endlessly redo
	79	* the fault.
	80	*/
	81	survive:
	82	switch (handle_mm_fault(mm, vma, address, writeaccess)) {
	83	case VM_FAULT_MINOR:
	84	tsk->min_flt++;
	85	break;
	86	case VM_FAULT_MAJOR:
	87	tsk->maj_flt++;
	88	break;
	89	case VM_FAULT_SIGBUS:
	90	goto do_sigbus;
	91	case VM_FAULT_OOM:
	92	goto out_of_memory;
	93	default:
	94	BUG();
	95	}
	96
	97	up_read(&mm->mmap_sem);
	98	return;
	99
	100	/*
	101	* Something tried to access memory that isn't in our memory map..
	102	* Fix it, but check if it's kernel or user first..
	103	*/
	104	bad_area:
	105	up_read(&mm->mmap_sem);
	106
	107	if (user_mode(regs)) {
	108	tsk->thread.address = address;
	109	tsk->thread.error_code = writeaccess;
	110	force_sig(SIGSEGV, tsk);
	111	return;
	112	}
	113
	114	no_context:
	115	/* Are we prepared to handle this kernel fault? */
	116	if (fixup_exception(regs))
	117	return;
	118
	119	/*
	120	* Oops. The kernel tried to access some bad page. We'll have to
	121	* terminate things with extreme prejudice.
	122	*
	123	*/
	124	if (address < PAGE_SIZE)
	125	printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
	126	else
	127	printk(KERN_ALERT "Unable to handle kernel paging request");
	128	printk(" at virtual address %08lx\n", address);
	129	printk(KERN_ALERT "pc = %08lx\n", regs->pc);
	130	asm volatile("mov.l %1, %0"
	131	: "=r" (page)
	132	: "m" (__m(MMU_TTB)));
	133	if (page) {
	134	page = ((unsigned long *) page)[address >> 22];
	135	printk(KERN_ALERT "*pde = %08lx\n", page);
	136	if (page & _PAGE_PRESENT) {
137	page &= PAGE_MASK;
138	address &= 0x003ff000;
139	page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT];
140	printk(KERN_ALERT "*pte = %08lx\n", page);
141	}
142	}
143	die("Oops", regs, writeaccess);
144	do_exit(SIGKILL);
145
146	/*
147	* We ran out of memory, or some other thing happened to us that made
148	* us unable to handle the page fault gracefully.
149	*/
150	out_of_memory:
151	up_read(&mm->mmap_sem);
f400e198	152	if (is_init(current)) {
1da177e4 LT	153	yield();
	154	down_read(&mm->mmap_sem);
	155	goto survive;
	156	}
	157	printk("VM: killing process %s\n", tsk->comm);
	158	if (user_mode(regs))
	159	do_exit(SIGKILL);
	160	goto no_context;
	161
	162	do_sigbus:
	163	up_read(&mm->mmap_sem);
	164
	165	/*
	166	* Send a sigbus, regardless of whether we were in kernel
	167	* or user mode.
	168	*/
	169	tsk->thread.address = address;
	170	tsk->thread.error_code = writeaccess;
	171	tsk->thread.trap_no = 14;
	172	force_sig(SIGBUS, tsk);
	173
	174	/* Kernel mode? Handle exceptions or die */
	175	if (!user_mode(regs))
	176	goto no_context;
	177	}
	178
26ff6c11	179	#ifdef CONFIG_SH_STORE_QUEUES
1da177e4	180	/*
26ff6c11 PM	181	* This is a special case for the SH-4 store queues, as pages for this
	182	* space still need to be faulted in before it's possible to flush the
	183	* store queue cache for writeout to the remapped region.
	184	*/
	185	#define P3_ADDR_MAX (P4SEG_STORE_QUE + 0x04000000)
	186	#else
	187	#define P3_ADDR_MAX P4SEG
	188	#endif
	189
	190	/*
	191	* Called with interrupts disabled.
1da177e4	192	*/
0f08f338 PM	193	asmlinkage int __kprobes __do_page_fault(struct pt_regs *regs,
	194	unsigned long writeaccess,
	195	unsigned long address)
1da177e4	196	{
60ec5585	197	pgd_t *pgd;
26ff6c11	198	pud_t *pud;
1da177e4 LT	199	pmd_t *pmd;
	200	pte_t *pte;
	201	pte_t entry;
0f08f338	202	struct mm_struct *mm = current->mm;
60ec5585 HD	203	spinlock_t *ptl;
60ec5585 HD	204	int ret = 1;
1da177e4 LT	205
	206	#ifdef CONFIG_SH_KGDB
	207	if (kgdb_nofault && kgdb_bus_err_hook)
	208	kgdb_bus_err_hook();
	209	#endif
	210
26ff6c11 PM	211	/*
	212	* We don't take page faults for P1, P2, and parts of P4, these
	213	* are always mapped, whether it be due to legacy behaviour in
	214	* 29-bit mode, or due to PMB configuration in 32-bit mode.
	215	*/
f647d33f	216	if (address >= P3SEG && address < P3_ADDR_MAX) {
60ec5585	217	pgd = pgd_offset_k(address);
f647d33f PM	218	mm = NULL;
f647d33f PM	219	} else {
0f08f338	220	if (unlikely(address >= TASK_SIZE \|\| !mm))
26ff6c11 PM	221	return 1;
26ff6c11 PM	222
0f08f338	223	pgd = pgd_offset(mm, address);
26ff6c11	224	}
1da177e4	225
26ff6c11 PM	226	pud = pud_offset(pgd, address);
	227	if (pud_none_or_clear_bad(pud))
	228	return 1;
	229	pmd = pmd_offset(pud, address);
60ec5585	230	if (pmd_none_or_clear_bad(pmd))
1da177e4	231	return 1;
26ff6c11	232
60ec5585 HD	233	if (mm)
	234	pte = pte_offset_map_lock(mm, pmd, address, &ptl);
	235	else
	236	pte = pte_offset_kernel(pmd, address);
	237
1da177e4	238	entry = *pte;
26ff6c11 PM	239	if (unlikely(pte_none(entry) \|\| pte_not_present(entry)))
	240	goto unlock;
	241	if (unlikely(writeaccess && !pte_write(entry)))
60ec5585	242	goto unlock;
1da177e4 LT	243
	244	if (writeaccess)
	245	entry = pte_mkdirty(entry);
	246	entry = pte_mkyoung(entry);
	247
	248	#ifdef CONFIG_CPU_SH4
	249	/*
	250	* ITLB is not affected by "ldtlb" instruction.
	251	* So, we need to flush the entry by ourselves.
	252	*/
26ff6c11	253	__flush_tlb_page(get_asid(), address & PAGE_MASK);
1da177e4 LT	254	#endif
	255
	256	set_pte(pte, entry);
	257	update_mmu_cache(NULL, address, entry);
60ec5585 HD	258	ret = 0;
	259	unlock:
	260	if (mm)
	261	pte_unmap_unlock(pte, ptl);
	262	return ret;
1da177e4	263	}