[deliverable/linux.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/hardirq.h>
#include <linux/init.h>
#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <linux/page-flags.h>
#include <linux/sched.h>
#include <linux/highmem.h>

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

#include "fault.h"

/*
 * Fault status register encodings
 */
#define FSR_WRITE		(1 << 11)
#define FSR_FS4			(1 << 10)
#define FSR_FS3_0		(15)

static inline int fsr_fs(unsigned int fsr)
{
	return (fsr & FSR_FS3_0) | (fsr & FSR_FS4) >> 6;
}

#ifdef CONFIG_MMU

#ifdef CONFIG_KPROBES
static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
{
	int ret = 0;

	if (!user_mode(regs)) {
		/* kprobe_running() needs smp_processor_id() */
		preempt_disable();
		if (kprobe_running() && kprobe_fault_handler(regs, fsr))
			ret = 1;
		preempt_enable();
	}

	return ret;
}
#else
static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
{
	return 0;
}
#endif

/*
 * 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));

		if (pmd_none(*pmd))
			break;

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

		/* We must not map this if we have highmem enabled */
		if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
			break;

		pte = pte_offset_map(pmd, addr);
		printk(", *pte=%08lx", pte_val(*pte));
		printk(", *ppte=%08lx", pte_val(pte[-PTRS_PER_PTE]));
		pte_unmap(pte);
	} while(0);

	printk("\n");
}
#else					/* CONFIG_MMU */
void show_pte(struct mm_struct *mm, unsigned long addr)
{ }
#endif					/* CONFIG_MMU */

/*
 * 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);
}

#ifdef CONFIG_MMU
#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 & FSR_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.
	 */
	fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, (fsr & FSR_WRITE) ? FAULT_FLAG_WRITE : 0);
	if (unlikely(fault & VM_FAULT_ERROR))
		return fault;
	if (fault & VM_FAULT_MAJOR)
		tsk->maj_flt++;
	else
		tsk->min_flt++;
	return fault;

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

static int __kprobes
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;

	if (notify_page_fault(regs, fsr))
		return 0;

	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 (fault & VM_FAULT_OOM) {
		/*
		 * We ran out of memory, call the OOM killer, and return to
		 * userspace (which will retry the fault, or kill us if we
		 * got oom-killed)
		 */
		pagefault_out_of_memory();
		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_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;
}
#else					/* CONFIG_MMU */
static int
do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
	return 0;
}
#endif					/* CONFIG_MMU */

/*
 * 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.
 */
#ifdef CONFIG_MMU
static int __kprobes
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;
}
#else					/* CONFIG_MMU */
static int
do_translation_fault(unsigned long addr, unsigned int fsr,
		     struct pt_regs *regs)
{
	return 0;
}
#endif					/* CONFIG_MMU */

/*
 * 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_fs(fsr);
	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	13	#include <linux/mm.h>
67306da6	14	#include <linux/hardirq.h>
1da177e4	15	#include <linux/init.h>
25ce1dd7	16	#include <linux/kprobes.h>
33fa9b13	17	#include <linux/uaccess.h>
252d4c27	18	#include <linux/page-flags.h>
412bb0a6	19	#include <linux/sched.h>
65cec8e3	20	#include <linux/highmem.h>
1da177e4 LT	21
	22	#include <asm/system.h>
	23	#include <asm/pgtable.h>
	24	#include <asm/tlbflush.h>
1da177e4 LT	25
	26	#include "fault.h"
	27
c88d6aa7 RK	28	/*
	29	* Fault status register encodings
	30	*/
	31	#define FSR_WRITE (1 << 11)
	32	#define FSR_FS4 (1 << 10)
	33	#define FSR_FS3_0 (15)
	34
	35	static inline int fsr_fs(unsigned int fsr)
	36	{
	37	return (fsr & FSR_FS3_0) \| (fsr & FSR_FS4) >> 6;
	38	}
	39
09529f7a	40	#ifdef CONFIG_MMU
25ce1dd7 NP	41
	42	#ifdef CONFIG_KPROBES
	43	static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
	44	{
	45	int ret = 0;
	46
	47	if (!user_mode(regs)) {
	48	/* kprobe_running() needs smp_processor_id() */
	49	preempt_disable();
	50	if (kprobe_running() && kprobe_fault_handler(regs, fsr))
	51	ret = 1;
	52	preempt_enable();
	53	}
	54
	55	return ret;
	56	}
	57	#else
	58	static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
	59	{
	60	return 0;
	61	}
	62	#endif
	63
1da177e4 LT	64	/*
	65	* This is useful to dump out the page tables associated with
	66	* 'addr' in mm 'mm'.
	67	*/
	68	void show_pte(struct mm_struct *mm, unsigned long addr)
	69	{
	70	pgd_t *pgd;
	71
	72	if (!mm)
	73	mm = &init_mm;
	74
	75	printk(KERN_ALERT "pgd = %p\n", mm->pgd);
	76	pgd = pgd_offset(mm, addr);
	77	printk(KERN_ALERT "[%08lx] pgd=%08lx", addr, pgd_val(pgd));
	78
	79	do {
	80	pmd_t *pmd;
	81	pte_t *pte;
	82
	83	if (pgd_none(*pgd))
	84	break;
	85
	86	if (pgd_bad(*pgd)) {
	87	printk("(bad)");
	88	break;
	89	}
	90
	91	pmd = pmd_offset(pgd, addr);
da46c79a NP	92	if (PTRS_PER_PMD != 1)
da46c79a NP	93	printk(", pmd=%08lx", pmd_val(pmd));
1da177e4 LT	94
	95	if (pmd_none(*pmd))
	96	break;
	97
	98	if (pmd_bad(*pmd)) {
	99	printk("(bad)");
	100	break;
	101	}
	102
1da177e4	103	/* We must not map this if we have highmem enabled */
252d4c27 NP	104	if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
	105	break;
	106
1da177e4 LT	107	pte = pte_offset_map(pmd, addr);
	108	printk(", pte=%08lx", pte_val(pte));
	109	printk(", *ppte=%08lx", pte_val(pte[-PTRS_PER_PTE]));
	110	pte_unmap(pte);
1da177e4 LT	111	} while(0);
	112
	113	printk("\n");
	114	}
09529f7a CM	115	#else /* CONFIG_MMU */
	116	void show_pte(struct mm_struct *mm, unsigned long addr)
	117	{ }
	118	#endif /* CONFIG_MMU */
1da177e4 LT	119
	120	/*
	121	* Oops. The kernel tried to access some page that wasn't present.
	122	*/
	123	static void
	124	__do_kernel_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
	125	struct pt_regs *regs)
	126	{
	127	/*
	128	* Are we prepared to handle this kernel fault?
	129	*/
	130	if (fixup_exception(regs))
	131	return;
	132
	133	/*
	134	* No handler, we'll have to terminate things with extreme prejudice.
	135	*/
	136	bust_spinlocks(1);
	137	printk(KERN_ALERT
	138	"Unable to handle kernel %s at virtual address %08lx\n",
	139	(addr < PAGE_SIZE) ? "NULL pointer dereference" :
	140	"paging request", addr);
	141
	142	show_pte(mm, addr);
	143	die("Oops", regs, fsr);
	144	bust_spinlocks(0);
	145	do_exit(SIGKILL);
	146	}
	147
	148	/*
	149	* Something tried to access memory that isn't in our memory map..
	150	* User mode accesses just cause a SIGSEGV
	151	*/
	152	static void
	153	__do_user_fault(struct task_struct *tsk, unsigned long addr,
2d137c24	154	unsigned int fsr, unsigned int sig, int code,
2d137c24	155	struct pt_regs *regs)
1da177e4 LT	156	{
	157	struct siginfo si;
	158
	159	#ifdef CONFIG_DEBUG_USER
	160	if (user_debug & UDBG_SEGV) {
2d137c24	161	printk(KERN_DEBUG "%s: unhandled page fault (%d) at 0x%08lx, code 0x%03x\n",
2d137c24	162	tsk->comm, sig, addr, fsr);
1da177e4 LT	163	show_pte(tsk->mm, addr);
	164	show_regs(regs);
	165	}
	166	#endif
	167
	168	tsk->thread.address = addr;
	169	tsk->thread.error_code = fsr;
	170	tsk->thread.trap_no = 14;
2d137c24	171	si.si_signo = sig;
1da177e4 LT	172	si.si_errno = 0;
	173	si.si_code = code;
	174	si.si_addr = (void __user *)addr;
2d137c24	175	force_sig_info(sig, &si, tsk);
1da177e4 LT	176	}
1da177e4 LT	177
e5beac37	178	void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
1da177e4	179	{
e5beac37 RK	180	struct task_struct *tsk = current;
	181	struct mm_struct *mm = tsk->active_mm;
	182
1da177e4 LT	183	/*
	184	* If we are in kernel mode at this point, we
	185	* have no context to handle this fault with.
	186	*/
	187	if (user_mode(regs))
2d137c24	188	__do_user_fault(tsk, addr, fsr, SIGSEGV, SEGV_MAPERR, regs);
1da177e4 LT	189	else
	190	__do_kernel_fault(mm, addr, fsr, regs);
	191	}
	192
09529f7a	193	#ifdef CONFIG_MMU
5c72fc5c NP	194	#define VM_FAULT_BADMAP 0x010000
5c72fc5c NP	195	#define VM_FAULT_BADACCESS 0x020000
1da177e4 LT	196
	197	static int
	198	__do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
	199	struct task_struct *tsk)
	200	{
	201	struct vm_area_struct *vma;
	202	int fault, mask;
	203
	204	vma = find_vma(mm, addr);
	205	fault = VM_FAULT_BADMAP;
	206	if (!vma)
	207	goto out;
	208	if (vma->vm_start > addr)
	209	goto check_stack;
	210
	211	/*
	212	* Ok, we have a good vm_area for this
	213	* memory access, so we can handle it.
	214	*/
	215	good_area:
c88d6aa7	216	if (fsr & FSR_WRITE)
1da177e4 LT	217	mask = VM_WRITE;
1da177e4 LT	218	else
df67b3da	219	mask = VM_READ\|VM_EXEC\|VM_WRITE;
1da177e4 LT	220
	221	fault = VM_FAULT_BADACCESS;
	222	if (!(vma->vm_flags & mask))
	223	goto out;
	224
	225	/*
b42c6344 RK	226	* If for any reason at all we couldn't handle the fault, make
b42c6344 RK	227	* sure we exit gracefully rather than endlessly redo the fault.
1da177e4	228	*/
c88d6aa7	229	fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, (fsr & FSR_WRITE) ? FAULT_FLAG_WRITE : 0);
b42c6344 RK	230	if (unlikely(fault & VM_FAULT_ERROR))
b42c6344 RK	231	return fault;
83c54070	232	if (fault & VM_FAULT_MAJOR)
1da177e4	233	tsk->maj_flt++;
83c54070	234	else
1da177e4	235	tsk->min_flt++;
83c54070	236	return fault;
1da177e4	237
1da177e4 LT	238	check_stack:
	239	if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
	240	goto good_area;
	241	out:
	242	return fault;
	243	}
	244
785d3cd2	245	static int __kprobes
1da177e4 LT	246	do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
	247	{
	248	struct task_struct *tsk;
	249	struct mm_struct *mm;
2d137c24	250	int fault, sig, code;
1da177e4	251
25ce1dd7 NP	252	if (notify_page_fault(regs, fsr))
	253	return 0;
	254
1da177e4 LT	255	tsk = current;
	256	mm = tsk->mm;
	257
	258	/*
	259	* If we're in an interrupt or have no user
	260	* context, we must not take the fault..
	261	*/
6edaf68a	262	if (in_atomic() \|\| !mm)
1da177e4 LT	263	goto no_context;
1da177e4 LT	264
840ff6a4 RK	265	/*
	266	* As per x86, we may deadlock here. However, since the kernel only
	267	* validly references user space from well defined areas of the code,
	268	* we can bug out early if this is from code which shouldn't.
	269	*/
	270	if (!down_read_trylock(&mm->mmap_sem)) {
	271	if (!user_mode(regs) && !search_exception_tables(regs->ARM_pc))
	272	goto no_context;
	273	down_read(&mm->mmap_sem);
	274	}
	275
1da177e4 LT	276	fault = __do_page_fault(mm, addr, fsr, tsk);
	277	up_read(&mm->mmap_sem);
	278
	279	/*
ff2afb9d	280	* Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
1da177e4	281	*/
5c72fc5c	282	if (likely(!(fault & (VM_FAULT_ERROR \| VM_FAULT_BADMAP \| VM_FAULT_BADACCESS))))
1da177e4 LT	283	return 0;
1da177e4 LT	284
b42c6344 RK	285	if (fault & VM_FAULT_OOM) {
	286	/*
	287	* We ran out of memory, call the OOM killer, and return to
	288	* userspace (which will retry the fault, or kill us if we
	289	* got oom-killed)
	290	*/
	291	pagefault_out_of_memory();
	292	return 0;
	293	}
	294
1da177e4 LT	295	/*
	296	* If we are in kernel mode at this point, we
	297	* have no context to handle this fault with.
	298	*/
	299	if (!user_mode(regs))
	300	goto no_context;
	301
83c54070	302	if (fault & VM_FAULT_SIGBUS) {
2d137c24	303	/*
	304	* We had some memory, but were unable to
	305	* successfully fix up this page fault.
	306	*/
	307	sig = SIGBUS;
	308	code = BUS_ADRERR;
83c54070	309	} else {
2d137c24	310	/*
	311	* Something tried to access memory that
	312	* isn't in our memory map..
	313	*/
	314	sig = SIGSEGV;
	315	code = fault == VM_FAULT_BADACCESS ?
	316	SEGV_ACCERR : SEGV_MAPERR;
1da177e4	317	}
1da177e4	318
2d137c24	319	__do_user_fault(tsk, addr, fsr, sig, code, regs);
2d137c24	320	return 0;
1da177e4 LT	321
	322	no_context:
	323	__do_kernel_fault(mm, addr, fsr, regs);
	324	return 0;
	325	}
09529f7a CM	326	#else /* CONFIG_MMU */
	327	static int
	328	do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
	329	{
	330	return 0;
	331	}
	332	#endif /* CONFIG_MMU */
1da177e4 LT	333
	334	/*
	335	* First Level Translation Fault Handler
	336	*
	337	* We enter here because the first level page table doesn't contain
	338	* a valid entry for the address.
	339	*
	340	* If the address is in kernel space (>= TASK_SIZE), then we are
	341	* probably faulting in the vmalloc() area.
	342	*
	343	* If the init_task's first level page tables contains the relevant
	344	* entry, we copy the it to this task. If not, we send the process
	345	* a signal, fixup the exception, or oops the kernel.
	346	*
	347	* NOTE! We MUST NOT take any locks for this case. We may be in an
	348	* interrupt or a critical region, and should only copy the information
	349	* from the master page table, nothing more.
	350	*/
09529f7a	351	#ifdef CONFIG_MMU
785d3cd2	352	static int __kprobes
1da177e4 LT	353	do_translation_fault(unsigned long addr, unsigned int fsr,
	354	struct pt_regs *regs)
	355	{
1da177e4 LT	356	unsigned int index;
	357	pgd_t pgd, pgd_k;
	358	pmd_t pmd, pmd_k;
	359
	360	if (addr < TASK_SIZE)
	361	return do_page_fault(addr, fsr, regs);
	362
	363	index = pgd_index(addr);
	364
	365	/*
	366	* FIXME: CP15 C1 is write only on ARMv3 architectures.
	367	*/
	368	pgd = cpu_get_pgd() + index;
	369	pgd_k = init_mm.pgd + index;
	370
	371	if (pgd_none(*pgd_k))
	372	goto bad_area;
	373
	374	if (!pgd_present(*pgd))
	375	set_pgd(pgd, *pgd_k);
	376
	377	pmd_k = pmd_offset(pgd_k, addr);
	378	pmd = pmd_offset(pgd, addr);
	379
	380	if (pmd_none(*pmd_k))
	381	goto bad_area;
	382
	383	copy_pmd(pmd, pmd_k);
	384	return 0;
	385
	386	bad_area:
e5beac37	387	do_bad_area(addr, fsr, regs);
1da177e4 LT	388	return 0;
1da177e4 LT	389	}
09529f7a CM	390	#else /* CONFIG_MMU */
	391	static int
	392	do_translation_fault(unsigned long addr, unsigned int fsr,
	393	struct pt_regs *regs)
	394	{
	395	return 0;
	396	}
	397	#endif /* CONFIG_MMU */
1da177e4 LT	398
	399	/*
	400	* Some section permission faults need to be handled gracefully.
	401	* They can happen due to a __{get,put}_user during an oops.
	402	*/
	403	static int
	404	do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
	405	{
e5beac37	406	do_bad_area(addr, fsr, regs);
1da177e4 LT	407	return 0;
	408	}
	409
	410	/*
	411	* This abort handler always returns "fault".
	412	*/
	413	static int
	414	do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
	415	{
	416	return 1;
	417	}
	418
	419	static struct fsr_info {
	420	int (fn)(unsigned long addr, unsigned int fsr, struct pt_regs regs);
	421	int sig;
cfb0810e	422	int code;
1da177e4 LT	423	const char *name;
	424	} fsr_info[] = {
	425	/*
	426	* The following are the standard ARMv3 and ARMv4 aborts. ARMv5
	427	* defines these to be "precise" aborts.
	428	*/
cfb0810e RK	429	{ do_bad, SIGSEGV, 0, "vector exception" },
	430	{ do_bad, SIGILL, BUS_ADRALN, "alignment exception" },
	431	{ do_bad, SIGKILL, 0, "terminal exception" },
	432	{ do_bad, SIGILL, BUS_ADRALN, "alignment exception" },
	433	{ do_bad, SIGBUS, 0, "external abort on linefetch" },
	434	{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "section translation fault" },
	435	{ do_bad, SIGBUS, 0, "external abort on linefetch" },
	436	{ do_page_fault, SIGSEGV, SEGV_MAPERR, "page translation fault" },
	437	{ do_bad, SIGBUS, 0, "external abort on non-linefetch" },
	438	{ do_bad, SIGSEGV, SEGV_ACCERR, "section domain fault" },
	439	{ do_bad, SIGBUS, 0, "external abort on non-linefetch" },
	440	{ do_bad, SIGSEGV, SEGV_ACCERR, "page domain fault" },
	441	{ do_bad, SIGBUS, 0, "external abort on translation" },
	442	{ do_sect_fault, SIGSEGV, SEGV_ACCERR, "section permission fault" },
	443	{ do_bad, SIGBUS, 0, "external abort on translation" },
	444	{ do_page_fault, SIGSEGV, SEGV_ACCERR, "page permission fault" },
1da177e4 LT	445	/*
	446	* The following are "imprecise" aborts, which are signalled by bit
	447	* 10 of the FSR, and may not be recoverable. These are only
	448	* supported if the CPU abort handler supports bit 10.
	449	*/
cfb0810e RK	450	{ do_bad, SIGBUS, 0, "unknown 16" },
	451	{ do_bad, SIGBUS, 0, "unknown 17" },
	452	{ do_bad, SIGBUS, 0, "unknown 18" },
	453	{ do_bad, SIGBUS, 0, "unknown 19" },
	454	{ do_bad, SIGBUS, 0, "lock abort" }, /* xscale */
	455	{ do_bad, SIGBUS, 0, "unknown 21" },
	456	{ do_bad, SIGBUS, BUS_OBJERR, "imprecise external abort" }, /* xscale */
	457	{ do_bad, SIGBUS, 0, "unknown 23" },
	458	{ do_bad, SIGBUS, 0, "dcache parity error" }, /* xscale */
	459	{ do_bad, SIGBUS, 0, "unknown 25" },
	460	{ do_bad, SIGBUS, 0, "unknown 26" },
	461	{ do_bad, SIGBUS, 0, "unknown 27" },
	462	{ do_bad, SIGBUS, 0, "unknown 28" },
	463	{ do_bad, SIGBUS, 0, "unknown 29" },
	464	{ do_bad, SIGBUS, 0, "unknown 30" },
	465	{ do_bad, SIGBUS, 0, "unknown 31" }
1da177e4 LT	466	};
	467
	468	void __init
	469	hook_fault_code(int nr, int (fn)(unsigned long, unsigned int, struct pt_regs ),
	470	int sig, const char *name)
	471	{
	472	if (nr >= 0 && nr < ARRAY_SIZE(fsr_info)) {
	473	fsr_info[nr].fn = fn;
	474	fsr_info[nr].sig = sig;
	475	fsr_info[nr].name = name;
	476	}
	477	}
	478
	479	/*
	480	* Dispatch a data abort to the relevant handler.
	481	*/
7ab3f8d5	482	asmlinkage void __exception
1da177e4 LT	483	do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
1da177e4 LT	484	{
c88d6aa7	485	const struct fsr_info *inf = fsr_info + fsr_fs(fsr);
cfb0810e	486	struct siginfo info;
1da177e4 LT	487
	488	if (!inf->fn(addr, fsr, regs))
	489	return;
	490
	491	printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
	492	inf->name, fsr, addr);
cfb0810e RK	493
	494	info.si_signo = inf->sig;
	495	info.si_errno = 0;
	496	info.si_code = inf->code;
	497	info.si_addr = (void __user *)addr;
1eeb66a1	498	arm_notify_die("", regs, &info, fsr, 0);
1da177e4 LT	499	}
1da177e4 LT	500
7ab3f8d5	501	asmlinkage void __exception
1da177e4 LT	502	do_PrefetchAbort(unsigned long addr, struct pt_regs *regs)
	503	{
	504	do_translation_fault(addr, 0, regs);
	505	}
	506