[linux-2.6-block.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 __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;
	unsigned long page;
	int si_code;
	siginfo_t info;

#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 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:
	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)) {
		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.
 *
 */
	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.
	 */
	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;
	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	*/
b5a1bcbe SM	29	asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
	30	unsigned long writeaccess,
	31	unsigned long address)
1da177e4 LT	32	{
	33	struct task_struct *tsk;
	34	struct mm_struct *mm;
	35	struct vm_area_struct * vma;
	36	unsigned long page;
b5a1bcbe SM	37	int si_code;
b5a1bcbe SM	38	siginfo_t info;
1da177e4 LT	39
	40	#ifdef CONFIG_SH_KGDB
	41	if (kgdb_nofault && kgdb_bus_err_hook)
	42	kgdb_bus_err_hook();
	43	#endif
	44
	45	tsk = current;
	46	mm = tsk->mm;
b5a1bcbe	47	si_code = SEGV_MAPERR;
1da177e4 LT	48
	49	/*
	50	* If we're in an interrupt or have no user
	51	* context, we must not take the fault..
	52	*/
	53	if (in_atomic() \|\| !mm)
	54	goto no_context;
	55
	56	down_read(&mm->mmap_sem);
	57
	58	vma = find_vma(mm, address);
	59	if (!vma)
	60	goto bad_area;
	61	if (vma->vm_start <= address)
	62	goto good_area;
	63	if (!(vma->vm_flags & VM_GROWSDOWN))
	64	goto bad_area;
	65	if (expand_stack(vma, address))
	66	goto bad_area;
	67	/*
	68	* Ok, we have a good vm_area for this memory access, so
	69	* we can handle it..
	70	*/
	71	good_area:
b5a1bcbe	72	si_code = SEGV_ACCERR;
1da177e4 LT	73	if (writeaccess) {
	74	if (!(vma->vm_flags & VM_WRITE))
	75	goto bad_area;
	76	} else {
df67b3da	77	if (!(vma->vm_flags & (VM_READ \| VM_EXEC \| VM_WRITE)))
1da177e4 LT	78	goto bad_area;
	79	}
	80
	81	/*
	82	* If for any reason at all we couldn't handle the fault,
	83	* make sure we exit gracefully rather than endlessly redo
	84	* the fault.
	85	*/
	86	survive:
	87	switch (handle_mm_fault(mm, vma, address, writeaccess)) {
	88	case VM_FAULT_MINOR:
	89	tsk->min_flt++;
	90	break;
	91	case VM_FAULT_MAJOR:
	92	tsk->maj_flt++;
	93	break;
	94	case VM_FAULT_SIGBUS:
	95	goto do_sigbus;
	96	case VM_FAULT_OOM:
	97	goto out_of_memory;
	98	default:
	99	BUG();
	100	}
	101
	102	up_read(&mm->mmap_sem);
	103	return;
	104
	105	/*
	106	* Something tried to access memory that isn't in our memory map..
	107	* Fix it, but check if it's kernel or user first..
	108	*/
	109	bad_area:
	110	up_read(&mm->mmap_sem);
	111
	112	if (user_mode(regs)) {
b5a1bcbe SM	113	info.si_signo = SIGSEGV;
	114	info.si_errno = 0;
	115	info.si_code = si_code;
	116	info.si_addr = (void *) address;
	117	force_sig_info(SIGSEGV, &info, tsk);
1da177e4 LT	118	return;
	119	}
	120
	121	no_context:
	122	/* Are we prepared to handle this kernel fault? */
	123	if (fixup_exception(regs))
	124	return;
	125
	126	/*
	127	* Oops. The kernel tried to access some bad page. We'll have to
	128	* terminate things with extreme prejudice.
	129	*
	130	*/
	131	if (address < PAGE_SIZE)
	132	printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
	133	else
	134	printk(KERN_ALERT "Unable to handle kernel paging request");
	135	printk(" at virtual address %08lx\n", address);
	136	printk(KERN_ALERT "pc = %08lx\n", regs->pc);
	137	asm volatile("mov.l %1, %0"
	138	: "=r" (page)
	139	: "m" (__m(MMU_TTB)));
	140	if (page) {
	141	page = ((unsigned long *) page)[address >> 22];
	142	printk(KERN_ALERT "*pde = %08lx\n", page);
	143	if (page & _PAGE_PRESENT) {
	144	page &= PAGE_MASK;
	145	address &= 0x003ff000;
	146	page = ((unsigned long *) __va(page))[address >> PAGE_SHIFT];
	147	printk(KERN_ALERT "*pte = %08lx\n", page);
	148	}
	149	}
	150	die("Oops", regs, writeaccess);
	151	do_exit(SIGKILL);
	152
	153	/*
	154	* We ran out of memory, or some other thing happened to us that made
	155	* us unable to handle the page fault gracefully.
	156	*/
	157	out_of_memory:
	158	up_read(&mm->mmap_sem);
f400e198	159	if (is_init(current)) {
1da177e4 LT	160	yield();
	161	down_read(&mm->mmap_sem);
	162	goto survive;
	163	}
	164	printk("VM: killing process %s\n", tsk->comm);
	165	if (user_mode(regs))
	166	do_exit(SIGKILL);
	167	goto no_context;
	168
	169	do_sigbus:
	170	up_read(&mm->mmap_sem);
	171
	172	/*
	173	* Send a sigbus, regardless of whether we were in kernel
	174	* or user mode.
	175	*/
b5a1bcbe SM	176	info.si_signo = SIGBUS;
	177	info.si_errno = 0;
	178	info.si_code = BUS_ADRERR;
	179	info.si_addr = (void *)address;
	180	force_sig_info(SIGBUS, &info, tsk);
1da177e4 LT	181
	182	/* Kernel mode? Handle exceptions or die */
	183	if (!user_mode(regs))
	184	goto no_context;
	185	}
	186
26ff6c11	187	#ifdef CONFIG_SH_STORE_QUEUES
1da177e4	188	/*
26ff6c11 PM	189	* This is a special case for the SH-4 store queues, as pages for this
	190	* space still need to be faulted in before it's possible to flush the
	191	* store queue cache for writeout to the remapped region.
	192	*/
	193	#define P3_ADDR_MAX (P4SEG_STORE_QUE + 0x04000000)
	194	#else
	195	#define P3_ADDR_MAX P4SEG
	196	#endif
	197
	198	/*
	199	* Called with interrupts disabled.
1da177e4	200	*/
0f08f338 PM	201	asmlinkage int __kprobes __do_page_fault(struct pt_regs *regs,
	202	unsigned long writeaccess,
	203	unsigned long address)
1da177e4	204	{
60ec5585	205	pgd_t *pgd;
26ff6c11	206	pud_t *pud;
1da177e4 LT	207	pmd_t *pmd;
	208	pte_t *pte;
	209	pte_t entry;
0f08f338	210	struct mm_struct *mm = current->mm;
60ec5585 HD	211	spinlock_t *ptl;
60ec5585 HD	212	int ret = 1;
1da177e4 LT	213
	214	#ifdef CONFIG_SH_KGDB
	215	if (kgdb_nofault && kgdb_bus_err_hook)
	216	kgdb_bus_err_hook();
	217	#endif
	218
26ff6c11 PM	219	/*
	220	* We don't take page faults for P1, P2, and parts of P4, these
	221	* are always mapped, whether it be due to legacy behaviour in
	222	* 29-bit mode, or due to PMB configuration in 32-bit mode.
	223	*/
f647d33f	224	if (address >= P3SEG && address < P3_ADDR_MAX) {
60ec5585	225	pgd = pgd_offset_k(address);
f647d33f PM	226	mm = NULL;
f647d33f PM	227	} else {
0f08f338	228	if (unlikely(address >= TASK_SIZE \|\| !mm))
26ff6c11 PM	229	return 1;
26ff6c11 PM	230
0f08f338	231	pgd = pgd_offset(mm, address);
26ff6c11	232	}
1da177e4	233
26ff6c11 PM	234	pud = pud_offset(pgd, address);
	235	if (pud_none_or_clear_bad(pud))
	236	return 1;
	237	pmd = pmd_offset(pud, address);
60ec5585	238	if (pmd_none_or_clear_bad(pmd))
1da177e4	239	return 1;
26ff6c11	240
60ec5585 HD	241	if (mm)
	242	pte = pte_offset_map_lock(mm, pmd, address, &ptl);
	243	else
	244	pte = pte_offset_kernel(pmd, address);
	245
1da177e4	246	entry = *pte;
26ff6c11 PM	247	if (unlikely(pte_none(entry) \|\| pte_not_present(entry)))
	248	goto unlock;
	249	if (unlikely(writeaccess && !pte_write(entry)))
60ec5585	250	goto unlock;
1da177e4 LT	251
	252	if (writeaccess)
	253	entry = pte_mkdirty(entry);
	254	entry = pte_mkyoung(entry);
	255
	256	#ifdef CONFIG_CPU_SH4
	257	/*
	258	* ITLB is not affected by "ldtlb" instruction.
	259	* So, we need to flush the entry by ourselves.
	260	*/
26ff6c11	261	__flush_tlb_page(get_asid(), address & PAGE_MASK);
1da177e4 LT	262	#endif
	263
	264	set_pte(pte, entry);
	265	update_mmu_cache(NULL, address, entry);
60ec5585 HD	266	ret = 0;
	267	unlock:
	268	if (mm)
	269	pte_unmap_unlock(pte, ptl);
	270	return ret;
1da177e4	271	}