[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / arm / mm / fault.c

/*
 *  linux/arch/arm/mm/fault.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 *  Modifications for ARM processor (c) 1995-2004 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/signal.h>
#include <linux/ptrace.h>
#include <linux/mm.h>
#include <linux/init.h>

#include <asm/system.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/uaccess.h>

#include "fault.h"

/*
 * This is useful to dump out the page tables associated with
 * 'addr' in mm 'mm'.
 */
void show_pte(struct mm_struct *mm, unsigned long addr)
{
	pgd_t *pgd;

	if (!mm)
		mm = &init_mm;

	printk(KERN_ALERT "pgd = %p\n", mm->pgd);
	pgd = pgd_offset(mm, addr);
	printk(KERN_ALERT "[%08lx] *pgd=%08lx", addr, pgd_val(*pgd));

	do {
		pmd_t *pmd;
		pte_t *pte;

		if (pgd_none(*pgd))
			break;

		if (pgd_bad(*pgd)) {
			printk("(bad)");
			break;
		}

		pmd = pmd_offset(pgd, addr);
#if PTRS_PER_PMD != 1
		printk(", *pmd=%08lx", pmd_val(*pmd));
#endif

		if (pmd_none(*pmd))
			break;

		if (pmd_bad(*pmd)) {
			printk("(bad)");
			break;
		}

#ifndef CONFIG_HIGHMEM
		/* We must not map this if we have highmem enabled */
		pte = pte_offset_map(pmd, addr);
		printk(", *pte=%08lx", pte_val(*pte));
		printk(", *ppte=%08lx", pte_val(pte[-PTRS_PER_PTE]));
		pte_unmap(pte);
#endif
	} while(0);

	printk("\n");
}

/*
 * Oops.  The kernel tried to access some page that wasn't present.
 */
static void
__do_kernel_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
		  struct pt_regs *regs)
{
	/*
	 * Are we prepared to handle this kernel fault?
	 */
	if (fixup_exception(regs))
		return;

	/*
	 * No handler, we'll have to terminate things with extreme prejudice.
	 */
	bust_spinlocks(1);
	printk(KERN_ALERT
		"Unable to handle kernel %s at virtual address %08lx\n",
		(addr < PAGE_SIZE) ? "NULL pointer dereference" :
		"paging request", addr);

	show_pte(mm, addr);
	die("Oops", regs, fsr);
	bust_spinlocks(0);
	do_exit(SIGKILL);
}

/*
 * Something tried to access memory that isn't in our memory map..
 * User mode accesses just cause a SIGSEGV
 */
static void
__do_user_fault(struct task_struct *tsk, unsigned long addr,
		unsigned int fsr, unsigned int sig, int code,
		struct pt_regs *regs)
{
	struct siginfo si;

#ifdef CONFIG_DEBUG_USER
	if (user_debug & UDBG_SEGV) {
		printk(KERN_DEBUG "%s: unhandled page fault (%d) at 0x%08lx, code 0x%03x\n",
		       tsk->comm, sig, addr, fsr);
		show_pte(tsk->mm, addr);
		show_regs(regs);
	}
#endif

	tsk->thread.address = addr;
	tsk->thread.error_code = fsr;
	tsk->thread.trap_no = 14;
	si.si_signo = sig;
	si.si_errno = 0;
	si.si_code = code;
	si.si_addr = (void __user *)addr;
	force_sig_info(sig, &si, tsk);
}

void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
	struct task_struct *tsk = current;
	struct mm_struct *mm = tsk->active_mm;

	/*
	 * If we are in kernel mode at this point, we
	 * have no context to handle this fault with.
	 */
	if (user_mode(regs))
		__do_user_fault(tsk, addr, fsr, SIGSEGV, SEGV_MAPERR, regs);
	else
		__do_kernel_fault(mm, addr, fsr, regs);
}

#define VM_FAULT_BADMAP		(-20)
#define VM_FAULT_BADACCESS	(-21)

static int
__do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
		struct task_struct *tsk)
{
	struct vm_area_struct *vma;
	int fault, mask;

	vma = find_vma(mm, addr);
	fault = VM_FAULT_BADMAP;
	if (!vma)
		goto out;
	if (vma->vm_start > addr)
		goto check_stack;

	/*
	 * Ok, we have a good vm_area for this
	 * memory access, so we can handle it.
	 */
good_area:
	if (fsr & (1 << 11)) /* write? */
		mask = VM_WRITE;
	else
		mask = VM_READ|VM_EXEC|VM_WRITE;

	fault = VM_FAULT_BADACCESS;
	if (!(vma->vm_flags & mask))
		goto out;

	/*
	 * 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, addr & PAGE_MASK, fsr & (1 << 11));

	/*
	 * Handle the "normal" cases first - successful and sigbus
	 */
	switch (fault) {
	case VM_FAULT_MAJOR:
		tsk->maj_flt++;
		return fault;
	case VM_FAULT_MINOR:
		tsk->min_flt++;
	case VM_FAULT_SIGBUS:
		return fault;
	}

	if (!is_init(tsk))
		goto out;

	/*
	 * If we are out of memory for pid1, sleep for a while and retry
	 */
	up_read(&mm->mmap_sem);
	yield();
	down_read(&mm->mmap_sem);
	goto survive;

check_stack:
	if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
		goto good_area;
out:
	return fault;
}

static int
do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
	struct task_struct *tsk;
	struct mm_struct *mm;
	int fault, sig, code;

	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;

	/*
	 * As per x86, we may deadlock here.  However, since the kernel only
	 * validly references user space from well defined areas of the code,
	 * we can bug out early if this is from code which shouldn't.
	 */
	if (!down_read_trylock(&mm->mmap_sem)) {
		if (!user_mode(regs) && !search_exception_tables(regs->ARM_pc))
			goto no_context;
		down_read(&mm->mmap_sem);
	}

	fault = __do_page_fault(mm, addr, fsr, tsk);
	up_read(&mm->mmap_sem);

	/*
	 * Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
	 */
	if (fault >= VM_FAULT_MINOR)
		return 0;

	/*
	 * If we are in kernel mode at this point, we
	 * have no context to handle this fault with.
	 */
	if (!user_mode(regs))
		goto no_context;

	switch (fault) {
	case VM_FAULT_OOM:
		/*
		 * We ran out of memory, or some other thing
		 * happened to us that made us unable to handle
		 * the page fault gracefully.
		 */
		printk("VM: killing process %s\n", tsk->comm);
		do_exit(SIGKILL);
		return 0;

	case VM_FAULT_SIGBUS:
		/*
		 * We had some memory, but were unable to
		 * successfully fix up this page fault.
		 */
		sig = SIGBUS;
		code = BUS_ADRERR;
		break;

	default:
		/*
		 * Something tried to access memory that
		 * isn't in our memory map..
		 */
		sig = SIGSEGV;
		code = fault == VM_FAULT_BADACCESS ?
			SEGV_ACCERR : SEGV_MAPERR;
		break;
	}

	__do_user_fault(tsk, addr, fsr, sig, code, regs);
	return 0;

no_context:
	__do_kernel_fault(mm, addr, fsr, regs);
	return 0;
}

/*
 * First Level Translation Fault Handler
 *
 * We enter here because the first level page table doesn't contain
 * a valid entry for the address.
 *
 * If the address is in kernel space (>= TASK_SIZE), then we are
 * probably faulting in the vmalloc() area.
 *
 * If the init_task's first level page tables contains the relevant
 * entry, we copy the it to this task.  If not, we send the process
 * a signal, fixup the exception, or oops the kernel.
 *
 * 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.
 */
static int
do_translation_fault(unsigned long addr, unsigned int fsr,
		     struct pt_regs *regs)
{
	unsigned int index;
	pgd_t *pgd, *pgd_k;
	pmd_t *pmd, *pmd_k;

	if (addr < TASK_SIZE)
		return do_page_fault(addr, fsr, regs);

	index = pgd_index(addr);

	/*
	 * FIXME: CP15 C1 is write only on ARMv3 architectures.
	 */
	pgd = cpu_get_pgd() + index;
	pgd_k = init_mm.pgd + index;

	if (pgd_none(*pgd_k))
		goto bad_area;

	if (!pgd_present(*pgd))
		set_pgd(pgd, *pgd_k);

	pmd_k = pmd_offset(pgd_k, addr);
	pmd   = pmd_offset(pgd, addr);

	if (pmd_none(*pmd_k))
		goto bad_area;

	copy_pmd(pmd, pmd_k);
	return 0;

bad_area:
	do_bad_area(addr, fsr, regs);
	return 0;
}

/*
 * Some section permission faults need to be handled gracefully.
 * They can happen due to a __{get,put}_user during an oops.
 */
static int
do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
	do_bad_area(addr, fsr, regs);
	return 0;
}

/*
 * This abort handler always returns "fault".
 */
static int
do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
	return 1;
}

static struct fsr_info {
	int	(*fn)(unsigned long addr, unsigned int fsr, struct pt_regs *regs);
	int	sig;
	int	code;
	const char *name;
} fsr_info[] = {
	/*
	 * The following are the standard ARMv3 and ARMv4 aborts.  ARMv5
	 * defines these to be "precise" aborts.
	 */
	{ do_bad,		SIGSEGV, 0,		"vector exception"		   },
	{ do_bad,		SIGILL,	 BUS_ADRALN,	"alignment exception"		   },
	{ do_bad,		SIGKILL, 0,		"terminal exception"		   },
	{ do_bad,		SIGILL,	 BUS_ADRALN,	"alignment exception"		   },
	{ do_bad,		SIGBUS,	 0,		"external abort on linefetch"	   },
	{ do_translation_fault,	SIGSEGV, SEGV_MAPERR,	"section translation fault"	   },
	{ do_bad,		SIGBUS,	 0,		"external abort on linefetch"	   },
	{ do_page_fault,	SIGSEGV, SEGV_MAPERR,	"page translation fault"	   },
	{ do_bad,		SIGBUS,	 0,		"external abort on non-linefetch"  },
	{ do_bad,		SIGSEGV, SEGV_ACCERR,	"section domain fault"		   },
	{ do_bad,		SIGBUS,	 0,		"external abort on non-linefetch"  },
	{ do_bad,		SIGSEGV, SEGV_ACCERR,	"page domain fault"		   },
	{ do_bad,		SIGBUS,	 0,		"external abort on translation"	   },
	{ do_sect_fault,	SIGSEGV, SEGV_ACCERR,	"section permission fault"	   },
	{ do_bad,		SIGBUS,	 0,		"external abort on translation"	   },
	{ do_page_fault,	SIGSEGV, SEGV_ACCERR,	"page permission fault"		   },
	/*
	 * The following are "imprecise" aborts, which are signalled by bit
	 * 10 of the FSR, and may not be recoverable.  These are only
	 * supported if the CPU abort handler supports bit 10.
	 */
	{ do_bad,		SIGBUS,  0,		"unknown 16"			   },
	{ do_bad,		SIGBUS,  0,		"unknown 17"			   },
	{ do_bad,		SIGBUS,  0,		"unknown 18"			   },
	{ do_bad,		SIGBUS,  0,		"unknown 19"			   },
	{ do_bad,		SIGBUS,  0,		"lock abort"			   }, /* xscale */
	{ do_bad,		SIGBUS,  0,		"unknown 21"			   },
	{ do_bad,		SIGBUS,  BUS_OBJERR,	"imprecise external abort"	   }, /* xscale */
	{ do_bad,		SIGBUS,  0,		"unknown 23"			   },
	{ do_bad,		SIGBUS,  0,		"dcache parity error"		   }, /* xscale */
	{ do_bad,		SIGBUS,  0,		"unknown 25"			   },
	{ do_bad,		SIGBUS,  0,		"unknown 26"			   },
	{ do_bad,		SIGBUS,  0,		"unknown 27"			   },
	{ do_bad,		SIGBUS,  0,		"unknown 28"			   },
	{ do_bad,		SIGBUS,  0,		"unknown 29"			   },
	{ do_bad,		SIGBUS,  0,		"unknown 30"			   },
	{ do_bad,		SIGBUS,  0,		"unknown 31"			   }
};

void __init
hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int, struct pt_regs *),
		int sig, const char *name)
{
	if (nr >= 0 && nr < ARRAY_SIZE(fsr_info)) {
		fsr_info[nr].fn   = fn;
		fsr_info[nr].sig  = sig;
		fsr_info[nr].name = name;
	}
}

/*
 * Dispatch a data abort to the relevant handler.
 */
asmlinkage void
do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
	const struct fsr_info *inf = fsr_info + (fsr & 15) + ((fsr & (1 << 10)) >> 6);
	struct siginfo info;

	if (!inf->fn(addr, fsr, regs))
		return;

	printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
		inf->name, fsr, addr);

	info.si_signo = inf->sig;
	info.si_errno = 0;
	info.si_code  = inf->code;
	info.si_addr  = (void __user *)addr;
	notify_die("", regs, &info, fsr, 0);
}

asmlinkage void
do_PrefetchAbort(unsigned long addr, struct pt_regs *regs)
{
	do_translation_fault(addr, 0, regs);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/arch/arm/mm/fault.c
	3	*
	4	* Copyright (C) 1995 Linus Torvalds
	5	* Modifications for ARM processor (c) 1995-2004 Russell King
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*/
1da177e4 LT	11	#include <linux/module.h>
	12	#include <linux/signal.h>
	13	#include <linux/ptrace.h>
	14	#include <linux/mm.h>
	15	#include <linux/init.h>
	16
	17	#include <asm/system.h>
	18	#include <asm/pgtable.h>
	19	#include <asm/tlbflush.h>
	20	#include <asm/uaccess.h>
	21
	22	#include "fault.h"
	23
	24	/*
	25	* This is useful to dump out the page tables associated with
	26	* 'addr' in mm 'mm'.
	27	*/
	28	void show_pte(struct mm_struct *mm, unsigned long addr)
	29	{
	30	pgd_t *pgd;
	31
	32	if (!mm)
	33	mm = &init_mm;
	34
	35	printk(KERN_ALERT "pgd = %p\n", mm->pgd);
	36	pgd = pgd_offset(mm, addr);
	37	printk(KERN_ALERT "[%08lx] pgd=%08lx", addr, pgd_val(pgd));
	38
	39	do {
	40	pmd_t *pmd;
	41	pte_t *pte;
	42
	43	if (pgd_none(*pgd))
	44	break;
	45
	46	if (pgd_bad(*pgd)) {
	47	printk("(bad)");
	48	break;
	49	}
	50
	51	pmd = pmd_offset(pgd, addr);
	52	#if PTRS_PER_PMD != 1
	53	printk(", pmd=%08lx", pmd_val(pmd));
	54	#endif
	55
	56	if (pmd_none(*pmd))
	57	break;
	58
	59	if (pmd_bad(*pmd)) {
	60	printk("(bad)");
	61	break;
	62	}
	63
	64	#ifndef CONFIG_HIGHMEM
	65	/* We must not map this if we have highmem enabled */
	66	pte = pte_offset_map(pmd, addr);
	67	printk(", pte=%08lx", pte_val(pte));
	68	printk(", *ppte=%08lx", pte_val(pte[-PTRS_PER_PTE]));
	69	pte_unmap(pte);
	70	#endif
	71	} while(0);
	72
	73	printk("\n");
	74	}
75
76	/*
77	* Oops. The kernel tried to access some page that wasn't present.
78	*/
79	static void
80	__do_kernel_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
81	struct pt_regs *regs)
82	{
83	/*
84	* Are we prepared to handle this kernel fault?
85	*/
86	if (fixup_exception(regs))
87	return;
88
89	/*
90	* No handler, we'll have to terminate things with extreme prejudice.
91	*/
92	bust_spinlocks(1);
93	printk(KERN_ALERT
94	"Unable to handle kernel %s at virtual address %08lx\n",
95	(addr < PAGE_SIZE) ? "NULL pointer dereference" :
96	"paging request", addr);
97
98	show_pte(mm, addr);
99	die("Oops", regs, fsr);
100	bust_spinlocks(0);
101	do_exit(SIGKILL);
102	}
103
104	/*
105	* Something tried to access memory that isn't in our memory map..
106	* User mode accesses just cause a SIGSEGV
107	*/
108	static void
109	__do_user_fault(struct task_struct *tsk, unsigned long addr,
2d137c24 AM	110	unsigned int fsr, unsigned int sig, int code,
2d137c24 AM	111	struct pt_regs *regs)
1da177e4 LT	112	{
	113	struct siginfo si;
	114
	115	#ifdef CONFIG_DEBUG_USER
	116	if (user_debug & UDBG_SEGV) {
2d137c24 AM	117	printk(KERN_DEBUG "%s: unhandled page fault (%d) at 0x%08lx, code 0x%03x\n",
2d137c24 AM	118	tsk->comm, sig, addr, fsr);
1da177e4 LT	119	show_pte(tsk->mm, addr);
	120	show_regs(regs);
	121	}
	122	#endif
	123
	124	tsk->thread.address = addr;
	125	tsk->thread.error_code = fsr;
	126	tsk->thread.trap_no = 14;
2d137c24	127	si.si_signo = sig;
1da177e4 LT	128	si.si_errno = 0;
	129	si.si_code = code;
	130	si.si_addr = (void __user *)addr;
2d137c24	131	force_sig_info(sig, &si, tsk);
1da177e4 LT	132	}
1da177e4 LT	133
e5beac37	134	void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
1da177e4	135	{
e5beac37 RK	136	struct task_struct *tsk = current;
	137	struct mm_struct *mm = tsk->active_mm;
	138
1da177e4 LT	139	/*
	140	* If we are in kernel mode at this point, we
	141	* have no context to handle this fault with.
	142	*/
	143	if (user_mode(regs))
2d137c24	144	__do_user_fault(tsk, addr, fsr, SIGSEGV, SEGV_MAPERR, regs);
1da177e4 LT	145	else
	146	__do_kernel_fault(mm, addr, fsr, regs);
	147	}
	148
	149	#define VM_FAULT_BADMAP (-20)
	150	#define VM_FAULT_BADACCESS (-21)
	151
	152	static int
	153	__do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
	154	struct task_struct *tsk)
	155	{
	156	struct vm_area_struct *vma;
	157	int fault, mask;
	158
	159	vma = find_vma(mm, addr);
	160	fault = VM_FAULT_BADMAP;
	161	if (!vma)
	162	goto out;
	163	if (vma->vm_start > addr)
	164	goto check_stack;
	165
	166	/*
	167	* Ok, we have a good vm_area for this
	168	* memory access, so we can handle it.
	169	*/
	170	good_area:
	171	if (fsr & (1 << 11)) /* write? */
	172	mask = VM_WRITE;
	173	else
df67b3da	174	mask = VM_READ\|VM_EXEC\|VM_WRITE;
1da177e4 LT	175
	176	fault = VM_FAULT_BADACCESS;
	177	if (!(vma->vm_flags & mask))
	178	goto out;
	179
	180	/*
	181	* If for any reason at all we couldn't handle
	182	* the fault, make sure we exit gracefully rather
	183	* than endlessly redo the fault.
	184	*/
	185	survive:
	186	fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, fsr & (1 << 11));
	187
	188	/*
	189	* Handle the "normal" cases first - successful and sigbus
	190	*/
	191	switch (fault) {
	192	case VM_FAULT_MAJOR:
	193	tsk->maj_flt++;
	194	return fault;
	195	case VM_FAULT_MINOR:
	196	tsk->min_flt++;
	197	case VM_FAULT_SIGBUS:
	198	return fault;
	199	}
	200
f400e198	201	if (!is_init(tsk))
1da177e4 LT	202	goto out;
	203
	204	/*
2d137c24	205	* If we are out of memory for pid1, sleep for a while and retry
1da177e4	206	*/
2d137c24	207	up_read(&mm->mmap_sem);
1da177e4	208	yield();
2d137c24	209	down_read(&mm->mmap_sem);
1da177e4 LT	210	goto survive;
	211
	212	check_stack:
	213	if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
	214	goto good_area;
	215	out:
	216	return fault;
	217	}
	218
	219	static int
	220	do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
	221	{
	222	struct task_struct *tsk;
	223	struct mm_struct *mm;
2d137c24	224	int fault, sig, code;
1da177e4 LT	225
	226	tsk = current;
	227	mm = tsk->mm;
	228
	229	/*
	230	* If we're in an interrupt or have no user
	231	* context, we must not take the fault..
	232	*/
6edaf68a	233	if (in_atomic() \|\| !mm)
1da177e4 LT	234	goto no_context;
1da177e4 LT	235
840ff6a4 RK	236	/*
	237	* As per x86, we may deadlock here. However, since the kernel only
	238	* validly references user space from well defined areas of the code,
	239	* we can bug out early if this is from code which shouldn't.
	240	*/
	241	if (!down_read_trylock(&mm->mmap_sem)) {
	242	if (!user_mode(regs) && !search_exception_tables(regs->ARM_pc))
	243	goto no_context;
	244	down_read(&mm->mmap_sem);
	245	}
	246
1da177e4 LT	247	fault = __do_page_fault(mm, addr, fsr, tsk);
	248	up_read(&mm->mmap_sem);
	249
	250	/*
ff2afb9d	251	* Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
1da177e4	252	*/
ff2afb9d	253	if (fault >= VM_FAULT_MINOR)
1da177e4 LT	254	return 0;
1da177e4 LT	255
1da177e4 LT	256	/*
	257	* If we are in kernel mode at this point, we
	258	* have no context to handle this fault with.
	259	*/
	260	if (!user_mode(regs))
	261	goto no_context;
	262
2d137c24 AM	263	switch (fault) {
2d137c24 AM	264	case VM_FAULT_OOM:
1da177e4	265	/*
2d137c24 AM	266	* We ran out of memory, or some other thing
	267	* happened to us that made us unable to handle
	268	* the page fault gracefully.
1da177e4 LT	269	*/
	270	printk("VM: killing process %s\n", tsk->comm);
	271	do_exit(SIGKILL);
2d137c24	272	return 0;
1da177e4	273
ff2afb9d	274	case VM_FAULT_SIGBUS:
2d137c24 AM	275	/*
	276	* We had some memory, but were unable to
	277	* successfully fix up this page fault.
	278	*/
	279	sig = SIGBUS;
	280	code = BUS_ADRERR;
	281	break;
1da177e4	282
2d137c24 AM	283	default:
	284	/*
	285	* Something tried to access memory that
	286	* isn't in our memory map..
	287	*/
	288	sig = SIGSEGV;
	289	code = fault == VM_FAULT_BADACCESS ?
	290	SEGV_ACCERR : SEGV_MAPERR;
	291	break;
1da177e4	292	}
1da177e4	293
2d137c24 AM	294	__do_user_fault(tsk, addr, fsr, sig, code, regs);
2d137c24 AM	295	return 0;
1da177e4 LT	296
	297	no_context:
	298	__do_kernel_fault(mm, addr, fsr, regs);
	299	return 0;
	300	}
	301
	302	/*
	303	* First Level Translation Fault Handler
	304	*
	305	* We enter here because the first level page table doesn't contain
	306	* a valid entry for the address.
	307	*
	308	* If the address is in kernel space (>= TASK_SIZE), then we are
	309	* probably faulting in the vmalloc() area.
	310	*
	311	* If the init_task's first level page tables contains the relevant
	312	* entry, we copy the it to this task. If not, we send the process
	313	* a signal, fixup the exception, or oops the kernel.
	314	*
	315	* NOTE! We MUST NOT take any locks for this case. We may be in an
	316	* interrupt or a critical region, and should only copy the information
	317	* from the master page table, nothing more.
	318	*/
	319	static int
	320	do_translation_fault(unsigned long addr, unsigned int fsr,
	321	struct pt_regs *regs)
	322	{
1da177e4 LT	323	unsigned int index;
	324	pgd_t pgd, pgd_k;
	325	pmd_t pmd, pmd_k;
	326
	327	if (addr < TASK_SIZE)
	328	return do_page_fault(addr, fsr, regs);
	329
	330	index = pgd_index(addr);
	331
	332	/*
	333	* FIXME: CP15 C1 is write only on ARMv3 architectures.
	334	*/
	335	pgd = cpu_get_pgd() + index;
	336	pgd_k = init_mm.pgd + index;
	337
	338	if (pgd_none(*pgd_k))
	339	goto bad_area;
	340
	341	if (!pgd_present(*pgd))
	342	set_pgd(pgd, *pgd_k);
	343
	344	pmd_k = pmd_offset(pgd_k, addr);
	345	pmd = pmd_offset(pgd, addr);
	346
	347	if (pmd_none(*pmd_k))
	348	goto bad_area;
	349
	350	copy_pmd(pmd, pmd_k);
	351	return 0;
	352
	353	bad_area:
e5beac37	354	do_bad_area(addr, fsr, regs);
1da177e4 LT	355	return 0;
	356	}
	357
	358	/*
	359	* Some section permission faults need to be handled gracefully.
	360	* They can happen due to a __{get,put}_user during an oops.
	361	*/
	362	static int
	363	do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
	364	{
e5beac37	365	do_bad_area(addr, fsr, regs);
1da177e4 LT	366	return 0;
	367	}
	368
	369	/*
	370	* This abort handler always returns "fault".
	371	*/
	372	static int
	373	do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
	374	{
	375	return 1;
	376	}
	377
	378	static struct fsr_info {
	379	int (fn)(unsigned long addr, unsigned int fsr, struct pt_regs regs);
	380	int sig;
cfb0810e	381	int code;
1da177e4 LT	382	const char *name;
	383	} fsr_info[] = {
	384	/*
	385	* The following are the standard ARMv3 and ARMv4 aborts. ARMv5
	386	* defines these to be "precise" aborts.
	387	*/
cfb0810e RK	388	{ do_bad, SIGSEGV, 0, "vector exception" },
	389	{ do_bad, SIGILL, BUS_ADRALN, "alignment exception" },
	390	{ do_bad, SIGKILL, 0, "terminal exception" },
	391	{ do_bad, SIGILL, BUS_ADRALN, "alignment exception" },
	392	{ do_bad, SIGBUS, 0, "external abort on linefetch" },
	393	{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "section translation fault" },
	394	{ do_bad, SIGBUS, 0, "external abort on linefetch" },
	395	{ do_page_fault, SIGSEGV, SEGV_MAPERR, "page translation fault" },
	396	{ do_bad, SIGBUS, 0, "external abort on non-linefetch" },
	397	{ do_bad, SIGSEGV, SEGV_ACCERR, "section domain fault" },
	398	{ do_bad, SIGBUS, 0, "external abort on non-linefetch" },
	399	{ do_bad, SIGSEGV, SEGV_ACCERR, "page domain fault" },
	400	{ do_bad, SIGBUS, 0, "external abort on translation" },
	401	{ do_sect_fault, SIGSEGV, SEGV_ACCERR, "section permission fault" },
	402	{ do_bad, SIGBUS, 0, "external abort on translation" },
	403	{ do_page_fault, SIGSEGV, SEGV_ACCERR, "page permission fault" },
1da177e4 LT	404	/*
	405	* The following are "imprecise" aborts, which are signalled by bit
	406	* 10 of the FSR, and may not be recoverable. These are only
	407	* supported if the CPU abort handler supports bit 10.
	408	*/
cfb0810e RK	409	{ do_bad, SIGBUS, 0, "unknown 16" },
	410	{ do_bad, SIGBUS, 0, "unknown 17" },
	411	{ do_bad, SIGBUS, 0, "unknown 18" },
	412	{ do_bad, SIGBUS, 0, "unknown 19" },
	413	{ do_bad, SIGBUS, 0, "lock abort" }, /* xscale */
	414	{ do_bad, SIGBUS, 0, "unknown 21" },
	415	{ do_bad, SIGBUS, BUS_OBJERR, "imprecise external abort" }, /* xscale */
	416	{ do_bad, SIGBUS, 0, "unknown 23" },
	417	{ do_bad, SIGBUS, 0, "dcache parity error" }, /* xscale */
	418	{ do_bad, SIGBUS, 0, "unknown 25" },
	419	{ do_bad, SIGBUS, 0, "unknown 26" },
	420	{ do_bad, SIGBUS, 0, "unknown 27" },
	421	{ do_bad, SIGBUS, 0, "unknown 28" },
	422	{ do_bad, SIGBUS, 0, "unknown 29" },
	423	{ do_bad, SIGBUS, 0, "unknown 30" },
	424	{ do_bad, SIGBUS, 0, "unknown 31" }
1da177e4 LT	425	};
	426
	427	void __init
	428	hook_fault_code(int nr, int (fn)(unsigned long, unsigned int, struct pt_regs ),
	429	int sig, const char *name)
	430	{
	431	if (nr >= 0 && nr < ARRAY_SIZE(fsr_info)) {
	432	fsr_info[nr].fn = fn;
	433	fsr_info[nr].sig = sig;
	434	fsr_info[nr].name = name;
	435	}
	436	}
	437
	438	/*
	439	* Dispatch a data abort to the relevant handler.
	440	*/
	441	asmlinkage void
	442	do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
	443	{
	444	const struct fsr_info *inf = fsr_info + (fsr & 15) + ((fsr & (1 << 10)) >> 6);
cfb0810e	445	struct siginfo info;
1da177e4 LT	446
	447	if (!inf->fn(addr, fsr, regs))
	448	return;
	449
	450	printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
	451	inf->name, fsr, addr);
cfb0810e RK	452
	453	info.si_signo = inf->sig;
	454	info.si_errno = 0;
	455	info.si_code = inf->code;
	456	info.si_addr = (void __user *)addr;
	457	notify_die("", regs, &info, fsr, 0);
1da177e4 LT	458	}
	459
	460	asmlinkage void
	461	do_PrefetchAbort(unsigned long addr, struct pt_regs *regs)
	462	{
	463	do_translation_fault(addr, 0, regs);
	464	}
	465