[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/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		0x010000
#define VM_FAULT_BADACCESS	0x020000

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));
	if (unlikely(fault & VM_FAULT_ERROR)) {
		if (fault & VM_FAULT_OOM)
			goto out_of_memory;
		else if (fault & VM_FAULT_SIGBUS)
			return fault;
		BUG();
	}
	if (fault & VM_FAULT_MAJOR)
		tsk->maj_flt++;
	else
		tsk->min_flt++;
	return fault;

out_of_memory:
	if (!is_global_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 (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS))))
		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;

	if (fault & 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_group_exit(SIGKILL);
		return 0;
	}
	if (fault & VM_FAULT_SIGBUS) {
		/*
		 * We had some memory, but were unable to
		 * successfully fix up this page fault.
		 */
		sig = SIGBUS;
		code = BUS_ADRERR;
	} else {
		/*
		 * Something tried to access memory that
		 * isn't in our memory map..
		 */
		sig = SIGSEGV;
		code = fault == VM_FAULT_BADACCESS ?
			SEGV_ACCERR : SEGV_MAPERR;
	}

	__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 __exception
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;
	arm_notify_die("", regs, &info, fsr, 0);
}

asmlinkage void __exception
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>
1da177e4 LT	12	#include <linux/signal.h>
1da177e4 LT	13	#include <linux/mm.h>
	14	#include <linux/init.h>
	15
	16	#include <asm/system.h>
	17	#include <asm/pgtable.h>
	18	#include <asm/tlbflush.h>
	19	#include <asm/uaccess.h>
	20
	21	#include "fault.h"
	22
	23	/*
	24	* This is useful to dump out the page tables associated with
	25	* 'addr' in mm 'mm'.
	26	*/
	27	void show_pte(struct mm_struct *mm, unsigned long addr)
	28	{
	29	pgd_t *pgd;
	30
	31	if (!mm)
	32	mm = &init_mm;
	33
	34	printk(KERN_ALERT "pgd = %p\n", mm->pgd);
	35	pgd = pgd_offset(mm, addr);
	36	printk(KERN_ALERT "[%08lx] pgd=%08lx", addr, pgd_val(pgd));
	37
	38	do {
	39	pmd_t *pmd;
	40	pte_t *pte;
	41
	42	if (pgd_none(*pgd))
	43	break;
	44
	45	if (pgd_bad(*pgd)) {
	46	printk("(bad)");
	47	break;
	48	}
	49
	50	pmd = pmd_offset(pgd, addr);
	51	#if PTRS_PER_PMD != 1
	52	printk(", pmd=%08lx", pmd_val(pmd));
	53	#endif
	54
	55	if (pmd_none(*pmd))
	56	break;
	57
	58	if (pmd_bad(*pmd)) {
	59	printk("(bad)");
	60	break;
	61	}
	62
	63	#ifndef CONFIG_HIGHMEM
	64	/* We must not map this if we have highmem enabled */
	65	pte = pte_offset_map(pmd, addr);
	66	printk(", pte=%08lx", pte_val(pte));
	67	printk(", *ppte=%08lx", pte_val(pte[-PTRS_PER_PTE]));
	68	pte_unmap(pte);
	69	#endif
	70	} while(0);
	71
	72	printk("\n");
	73	}
	74
	75	/*
	76	* Oops. The kernel tried to access some page that wasn't present.
77	*/
78	static void
79	__do_kernel_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
80	struct pt_regs *regs)
81	{
82	/*
83	* Are we prepared to handle this kernel fault?
84	*/
85	if (fixup_exception(regs))
86	return;
87
88	/*
89	* No handler, we'll have to terminate things with extreme prejudice.
90	*/
91	bust_spinlocks(1);
92	printk(KERN_ALERT
93	"Unable to handle kernel %s at virtual address %08lx\n",
94	(addr < PAGE_SIZE) ? "NULL pointer dereference" :
95	"paging request", addr);
96
97	show_pte(mm, addr);
98	die("Oops", regs, fsr);
99	bust_spinlocks(0);
100	do_exit(SIGKILL);
101	}
102
103	/*
104	* Something tried to access memory that isn't in our memory map..
105	* User mode accesses just cause a SIGSEGV
106	*/
107	static void
108	__do_user_fault(struct task_struct *tsk, unsigned long addr,
2d137c24 AM	109	unsigned int fsr, unsigned int sig, int code,
2d137c24 AM	110	struct pt_regs *regs)
1da177e4 LT	111	{
	112	struct siginfo si;
	113
	114	#ifdef CONFIG_DEBUG_USER
	115	if (user_debug & UDBG_SEGV) {
2d137c24 AM	116	printk(KERN_DEBUG "%s: unhandled page fault (%d) at 0x%08lx, code 0x%03x\n",
2d137c24 AM	117	tsk->comm, sig, addr, fsr);
1da177e4 LT	118	show_pte(tsk->mm, addr);
	119	show_regs(regs);
	120	}
	121	#endif
	122
	123	tsk->thread.address = addr;
	124	tsk->thread.error_code = fsr;
	125	tsk->thread.trap_no = 14;
2d137c24	126	si.si_signo = sig;
1da177e4 LT	127	si.si_errno = 0;
	128	si.si_code = code;
	129	si.si_addr = (void __user *)addr;
2d137c24	130	force_sig_info(sig, &si, tsk);
1da177e4 LT	131	}
1da177e4 LT	132
e5beac37	133	void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
1da177e4	134	{
e5beac37 RK	135	struct task_struct *tsk = current;
	136	struct mm_struct *mm = tsk->active_mm;
	137
1da177e4 LT	138	/*
	139	* If we are in kernel mode at this point, we
	140	* have no context to handle this fault with.
	141	*/
	142	if (user_mode(regs))
2d137c24	143	__do_user_fault(tsk, addr, fsr, SIGSEGV, SEGV_MAPERR, regs);
1da177e4 LT	144	else
	145	__do_kernel_fault(mm, addr, fsr, regs);
	146	}
	147
5c72fc5c NP	148	#define VM_FAULT_BADMAP 0x010000
5c72fc5c NP	149	#define VM_FAULT_BADACCESS 0x020000
1da177e4 LT	150
	151	static int
	152	__do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
	153	struct task_struct *tsk)
	154	{
	155	struct vm_area_struct *vma;
	156	int fault, mask;
	157
	158	vma = find_vma(mm, addr);
	159	fault = VM_FAULT_BADMAP;
	160	if (!vma)
	161	goto out;
	162	if (vma->vm_start > addr)
	163	goto check_stack;
	164
	165	/*
	166	* Ok, we have a good vm_area for this
	167	* memory access, so we can handle it.
	168	*/
	169	good_area:
	170	if (fsr & (1 << 11)) /* write? */
	171	mask = VM_WRITE;
	172	else
df67b3da	173	mask = VM_READ\|VM_EXEC\|VM_WRITE;
1da177e4 LT	174
	175	fault = VM_FAULT_BADACCESS;
	176	if (!(vma->vm_flags & mask))
	177	goto out;
	178
	179	/*
	180	* If for any reason at all we couldn't handle
	181	* the fault, make sure we exit gracefully rather
	182	* than endlessly redo the fault.
	183	*/
	184	survive:
	185	fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, fsr & (1 << 11));
83c54070 NP	186	if (unlikely(fault & VM_FAULT_ERROR)) {
	187	if (fault & VM_FAULT_OOM)
	188	goto out_of_memory;
	189	else if (fault & VM_FAULT_SIGBUS)
	190	return fault;
	191	BUG();
	192	}
	193	if (fault & VM_FAULT_MAJOR)
1da177e4	194	tsk->maj_flt++;
83c54070	195	else
1da177e4	196	tsk->min_flt++;
83c54070	197	return fault;
1da177e4	198
83c54070	199	out_of_memory:
b460cbc5	200	if (!is_global_init(tsk))
1da177e4 LT	201	goto out;
	202
	203	/*
2d137c24	204	* If we are out of memory for pid1, sleep for a while and retry
1da177e4	205	*/
2d137c24	206	up_read(&mm->mmap_sem);
1da177e4	207	yield();
2d137c24	208	down_read(&mm->mmap_sem);
1da177e4 LT	209	goto survive;
	210
	211	check_stack:
	212	if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
	213	goto good_area;
	214	out:
	215	return fault;
	216	}
	217
	218	static int
	219	do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
	220	{
	221	struct task_struct *tsk;
	222	struct mm_struct *mm;
2d137c24	223	int fault, sig, code;
1da177e4 LT	224
	225	tsk = current;
	226	mm = tsk->mm;
	227
	228	/*
	229	* If we're in an interrupt or have no user
	230	* context, we must not take the fault..
	231	*/
6edaf68a	232	if (in_atomic() \|\| !mm)
1da177e4 LT	233	goto no_context;
1da177e4 LT	234
840ff6a4 RK	235	/*
	236	* As per x86, we may deadlock here. However, since the kernel only
	237	* validly references user space from well defined areas of the code,
	238	* we can bug out early if this is from code which shouldn't.
	239	*/
	240	if (!down_read_trylock(&mm->mmap_sem)) {
	241	if (!user_mode(regs) && !search_exception_tables(regs->ARM_pc))
	242	goto no_context;
	243	down_read(&mm->mmap_sem);
	244	}
	245
1da177e4 LT	246	fault = __do_page_fault(mm, addr, fsr, tsk);
	247	up_read(&mm->mmap_sem);
	248
	249	/*
ff2afb9d	250	* Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
1da177e4	251	*/
5c72fc5c	252	if (likely(!(fault & (VM_FAULT_ERROR \| VM_FAULT_BADMAP \| VM_FAULT_BADACCESS))))
1da177e4 LT	253	return 0;
1da177e4 LT	254
1da177e4 LT	255	/*
	256	* If we are in kernel mode at this point, we
	257	* have no context to handle this fault with.
	258	*/
	259	if (!user_mode(regs))
	260	goto no_context;
	261
83c54070	262	if (fault & VM_FAULT_OOM) {
1da177e4	263	/*
2d137c24 AM	264	* We ran out of memory, or some other thing
	265	* happened to us that made us unable to handle
	266	* the page fault gracefully.
1da177e4 LT	267	*/
1da177e4 LT	268	printk("VM: killing process %s\n", tsk->comm);
dcca2bde	269	do_group_exit(SIGKILL);
2d137c24	270	return 0;
83c54070 NP	271	}
83c54070 NP	272	if (fault & VM_FAULT_SIGBUS) {
2d137c24 AM	273	/*
	274	* We had some memory, but were unable to
	275	* successfully fix up this page fault.
	276	*/
	277	sig = SIGBUS;
	278	code = BUS_ADRERR;
83c54070	279	} else {
2d137c24 AM	280	/*
	281	* Something tried to access memory that
	282	* isn't in our memory map..
	283	*/
	284	sig = SIGSEGV;
	285	code = fault == VM_FAULT_BADACCESS ?
	286	SEGV_ACCERR : SEGV_MAPERR;
1da177e4	287	}
1da177e4	288
2d137c24 AM	289	__do_user_fault(tsk, addr, fsr, sig, code, regs);
2d137c24 AM	290	return 0;
1da177e4 LT	291
	292	no_context:
	293	__do_kernel_fault(mm, addr, fsr, regs);
	294	return 0;
	295	}
	296
	297	/*
	298	* First Level Translation Fault Handler
	299	*
	300	* We enter here because the first level page table doesn't contain
	301	* a valid entry for the address.
	302	*
	303	* If the address is in kernel space (>= TASK_SIZE), then we are
	304	* probably faulting in the vmalloc() area.
	305	*
	306	* If the init_task's first level page tables contains the relevant
	307	* entry, we copy the it to this task. If not, we send the process
	308	* a signal, fixup the exception, or oops the kernel.
	309	*
	310	* NOTE! We MUST NOT take any locks for this case. We may be in an
	311	* interrupt or a critical region, and should only copy the information
	312	* from the master page table, nothing more.
	313	*/
	314	static int
	315	do_translation_fault(unsigned long addr, unsigned int fsr,
	316	struct pt_regs *regs)
	317	{
1da177e4 LT	318	unsigned int index;
	319	pgd_t pgd, pgd_k;
	320	pmd_t pmd, pmd_k;
	321
	322	if (addr < TASK_SIZE)
	323	return do_page_fault(addr, fsr, regs);
	324
	325	index = pgd_index(addr);
	326
	327	/*
	328	* FIXME: CP15 C1 is write only on ARMv3 architectures.
	329	*/
	330	pgd = cpu_get_pgd() + index;
	331	pgd_k = init_mm.pgd + index;
	332
	333	if (pgd_none(*pgd_k))
	334	goto bad_area;
	335
	336	if (!pgd_present(*pgd))
	337	set_pgd(pgd, *pgd_k);
	338
	339	pmd_k = pmd_offset(pgd_k, addr);
	340	pmd = pmd_offset(pgd, addr);
	341
	342	if (pmd_none(*pmd_k))
	343	goto bad_area;
	344
	345	copy_pmd(pmd, pmd_k);
	346	return 0;
	347
	348	bad_area:
e5beac37	349	do_bad_area(addr, fsr, regs);
1da177e4 LT	350	return 0;
	351	}
	352
	353	/*
	354	* Some section permission faults need to be handled gracefully.
	355	* They can happen due to a __{get,put}_user during an oops.
	356	*/
	357	static int
	358	do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
	359	{
e5beac37	360	do_bad_area(addr, fsr, regs);
1da177e4 LT	361	return 0;
	362	}
	363
	364	/*
	365	* This abort handler always returns "fault".
	366	*/
	367	static int
	368	do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
	369	{
	370	return 1;
	371	}
	372
	373	static struct fsr_info {
	374	int (fn)(unsigned long addr, unsigned int fsr, struct pt_regs regs);
	375	int sig;
cfb0810e	376	int code;
1da177e4 LT	377	const char *name;
	378	} fsr_info[] = {
	379	/*
	380	* The following are the standard ARMv3 and ARMv4 aborts. ARMv5
	381	* defines these to be "precise" aborts.
	382	*/
cfb0810e RK	383	{ do_bad, SIGSEGV, 0, "vector exception" },
	384	{ do_bad, SIGILL, BUS_ADRALN, "alignment exception" },
	385	{ do_bad, SIGKILL, 0, "terminal exception" },
	386	{ do_bad, SIGILL, BUS_ADRALN, "alignment exception" },
	387	{ do_bad, SIGBUS, 0, "external abort on linefetch" },
	388	{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "section translation fault" },
	389	{ do_bad, SIGBUS, 0, "external abort on linefetch" },
	390	{ do_page_fault, SIGSEGV, SEGV_MAPERR, "page translation fault" },
	391	{ do_bad, SIGBUS, 0, "external abort on non-linefetch" },
	392	{ do_bad, SIGSEGV, SEGV_ACCERR, "section domain fault" },
	393	{ do_bad, SIGBUS, 0, "external abort on non-linefetch" },
	394	{ do_bad, SIGSEGV, SEGV_ACCERR, "page domain fault" },
	395	{ do_bad, SIGBUS, 0, "external abort on translation" },
	396	{ do_sect_fault, SIGSEGV, SEGV_ACCERR, "section permission fault" },
	397	{ do_bad, SIGBUS, 0, "external abort on translation" },
	398	{ do_page_fault, SIGSEGV, SEGV_ACCERR, "page permission fault" },
1da177e4 LT	399	/*
	400	* The following are "imprecise" aborts, which are signalled by bit
	401	* 10 of the FSR, and may not be recoverable. These are only
	402	* supported if the CPU abort handler supports bit 10.
	403	*/
cfb0810e RK	404	{ do_bad, SIGBUS, 0, "unknown 16" },
	405	{ do_bad, SIGBUS, 0, "unknown 17" },
	406	{ do_bad, SIGBUS, 0, "unknown 18" },
	407	{ do_bad, SIGBUS, 0, "unknown 19" },
	408	{ do_bad, SIGBUS, 0, "lock abort" }, /* xscale */
	409	{ do_bad, SIGBUS, 0, "unknown 21" },
	410	{ do_bad, SIGBUS, BUS_OBJERR, "imprecise external abort" }, /* xscale */
	411	{ do_bad, SIGBUS, 0, "unknown 23" },
	412	{ do_bad, SIGBUS, 0, "dcache parity error" }, /* xscale */
	413	{ do_bad, SIGBUS, 0, "unknown 25" },
	414	{ do_bad, SIGBUS, 0, "unknown 26" },
	415	{ do_bad, SIGBUS, 0, "unknown 27" },
	416	{ do_bad, SIGBUS, 0, "unknown 28" },
	417	{ do_bad, SIGBUS, 0, "unknown 29" },
	418	{ do_bad, SIGBUS, 0, "unknown 30" },
	419	{ do_bad, SIGBUS, 0, "unknown 31" }
1da177e4 LT	420	};
	421
	422	void __init
	423	hook_fault_code(int nr, int (fn)(unsigned long, unsigned int, struct pt_regs ),
	424	int sig, const char *name)
	425	{
	426	if (nr >= 0 && nr < ARRAY_SIZE(fsr_info)) {
	427	fsr_info[nr].fn = fn;
	428	fsr_info[nr].sig = sig;
	429	fsr_info[nr].name = name;
	430	}
	431	}
	432
	433	/*
	434	* Dispatch a data abort to the relevant handler.
	435	*/
7ab3f8d5	436	asmlinkage void __exception
1da177e4 LT	437	do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
	438	{
	439	const struct fsr_info *inf = fsr_info + (fsr & 15) + ((fsr & (1 << 10)) >> 6);
cfb0810e	440	struct siginfo info;
1da177e4 LT	441
	442	if (!inf->fn(addr, fsr, regs))
	443	return;
	444
	445	printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
	446	inf->name, fsr, addr);
cfb0810e RK	447
	448	info.si_signo = inf->sig;
	449	info.si_errno = 0;
	450	info.si_code = inf->code;
	451	info.si_addr = (void __user *)addr;
1eeb66a1	452	arm_notify_die("", regs, &info, fsr, 0);
1da177e4 LT	453	}
1da177e4 LT	454
7ab3f8d5	455	asmlinkage void __exception
1da177e4 LT	456	do_PrefetchAbort(unsigned long addr, struct pt_regs *regs)
	457	{
	458	do_translation_fault(addr, 0, regs);
	459	}
	460