[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/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 <linux/perf_event.h>

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

#include "fault.h"

/*
 * Fault status register encodings.  We steal bit 31 for our own purposes.
 */
#define FSR_LNX_PF		(1 << 31)
#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

/*
 * Check that the permissions on the VMA allow for the fault which occurred.
 * If we encountered a write fault, we must have write permission, otherwise
 * we allow any permission.
 */
static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
{
	unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;

	if (fsr & FSR_WRITE)
		mask = VM_WRITE;
	if (fsr & FSR_LNX_PF)
		mask = VM_EXEC;

	return vma->vm_flags & mask ? false : true;
}

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

	vma = find_vma(mm, addr);
	fault = VM_FAULT_BADMAP;
	if (unlikely(!vma))
		goto out;
	if (unlikely(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 (access_error(fsr, vma)) {
		fault = VM_FAULT_BADACCESS;
		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);
	} else {
		/*
		 * The above down_read_trylock() might have succeeded in
		 * which case, we'll have missed the might_sleep() from
		 * down_read()
		 */
		might_sleep();
#ifdef CONFIG_DEBUG_VM
		if (!user_mode(regs) &&
		    !search_exception_tables(regs->ARM_pc))
			goto no_context;
#endif
	}

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

	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, addr);
	if (fault & VM_FAULT_MAJOR)
		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 0, regs, addr);
	else if (fault & VM_FAULT_MINOR)
		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 0, regs, addr);

	/*
	 * 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);

	if (user_mode(regs))
		goto bad_area;

	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,		SIGBUS,	 BUS_ADRALN,	"alignment exception"		   },
	{ do_bad,		SIGKILL, 0,		"terminal exception"		   },
	{ do_bad,		SIGBUS,	 BUS_ADRALN,	"alignment exception"		   },
/* Do we need runtime check ? */
#if __LINUX_ARM_ARCH__ < 6
	{ do_bad,		SIGBUS,	 0,		"external abort on linefetch"	   },
#else
	{ do_translation_fault,	SIGSEGV, SEGV_MAPERR,	"I-cache maintenance fault"	   },
#endif
	{ 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, int code, const char *name)
{
	if (nr < 0 || nr >= ARRAY_SIZE(fsr_info))
		BUG();

	fsr_info[nr].fn   = fn;
	fsr_info[nr].sig  = sig;
	fsr_info[nr].code = code;
	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 & ~FSR_LNX_PF, 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);
}


static struct fsr_info ifsr_info[] = {
	{ do_bad,		SIGBUS,  0,		"unknown 0"			   },
	{ do_bad,		SIGBUS,  0,		"unknown 1"			   },
	{ do_bad,		SIGBUS,  0,		"debug event"			   },
	{ do_bad,		SIGSEGV, SEGV_ACCERR,	"section access flag fault"	   },
	{ do_bad,		SIGBUS,  0,		"unknown 4"			   },
	{ do_translation_fault,	SIGSEGV, SEGV_MAPERR,	"section translation fault"	   },
	{ do_bad,		SIGSEGV, SEGV_ACCERR,	"page access flag fault"	   },
	{ 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,		"unknown 10"			   },
	{ 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"		   },
	{ 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,		"unknown 20"			   },
	{ do_bad,		SIGBUS,  0,		"unknown 21"			   },
	{ do_bad,		SIGBUS,  0,		"unknown 22"			   },
	{ do_bad,		SIGBUS,  0,		"unknown 23"			   },
	{ do_bad,		SIGBUS,  0,		"unknown 24"			   },
	{ 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"			   },
};

asmlinkage void __exception
do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs)
{
	const struct fsr_info *inf = ifsr_info + fsr_fs(ifsr);
	struct siginfo info;

	if (!inf->fn(addr, ifsr | FSR_LNX_PF, regs))
		return;

	printk(KERN_ALERT "Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n",
		inf->name, ifsr, 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, ifsr, 0);
}
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>
7ada189f	21	#include <linux/perf_event.h>
1da177e4 LT	22
	23	#include <asm/system.h>
	24	#include <asm/pgtable.h>
	25	#include <asm/tlbflush.h>
1da177e4 LT	26
	27	#include "fault.h"
	28
c88d6aa7	29	/*
df297bf6	30	* Fault status register encodings. We steal bit 31 for our own purposes.
c88d6aa7	31	*/
df297bf6	32	#define FSR_LNX_PF (1 << 31)
c88d6aa7 RK	33	#define FSR_WRITE (1 << 11)
	34	#define FSR_FS4 (1 << 10)
	35	#define FSR_FS3_0 (15)
	36
	37	static inline int fsr_fs(unsigned int fsr)
	38	{
	39	return (fsr & FSR_FS3_0) \| (fsr & FSR_FS4) >> 6;
	40	}
	41
09529f7a	42	#ifdef CONFIG_MMU
25ce1dd7 NP	43
	44	#ifdef CONFIG_KPROBES
	45	static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
	46	{
	47	int ret = 0;
	48
	49	if (!user_mode(regs)) {
	50	/* kprobe_running() needs smp_processor_id() */
	51	preempt_disable();
	52	if (kprobe_running() && kprobe_fault_handler(regs, fsr))
	53	ret = 1;
	54	preempt_enable();
	55	}
	56
	57	return ret;
	58	}
	59	#else
	60	static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)
	61	{
	62	return 0;
	63	}
	64	#endif
	65
1da177e4 LT	66	/*
	67	* This is useful to dump out the page tables associated with
	68	* 'addr' in mm 'mm'.
	69	*/
	70	void show_pte(struct mm_struct *mm, unsigned long addr)
	71	{
	72	pgd_t *pgd;
	73
	74	if (!mm)
	75	mm = &init_mm;
	76
	77	printk(KERN_ALERT "pgd = %p\n", mm->pgd);
	78	pgd = pgd_offset(mm, addr);
	79	printk(KERN_ALERT "[%08lx] pgd=%08lx", addr, pgd_val(pgd));
	80
	81	do {
	82	pmd_t *pmd;
	83	pte_t *pte;
	84
	85	if (pgd_none(*pgd))
	86	break;
	87
	88	if (pgd_bad(*pgd)) {
	89	printk("(bad)");
	90	break;
	91	}
	92
	93	pmd = pmd_offset(pgd, addr);
da46c79a NP	94	if (PTRS_PER_PMD != 1)
da46c79a NP	95	printk(", pmd=%08lx", pmd_val(pmd));
1da177e4 LT	96
	97	if (pmd_none(*pmd))
	98	break;
	99
	100	if (pmd_bad(*pmd)) {
	101	printk("(bad)");
	102	break;
	103	}
	104
1da177e4	105	/* We must not map this if we have highmem enabled */
252d4c27 NP	106	if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
	107	break;
	108
1da177e4 LT	109	pte = pte_offset_map(pmd, addr);
	110	printk(", pte=%08lx", pte_val(pte));
	111	printk(", *ppte=%08lx", pte_val(pte[-PTRS_PER_PTE]));
	112	pte_unmap(pte);
1da177e4 LT	113	} while(0);
	114
	115	printk("\n");
	116	}
09529f7a CM	117	#else /* CONFIG_MMU */
	118	void show_pte(struct mm_struct *mm, unsigned long addr)
	119	{ }
	120	#endif /* CONFIG_MMU */
1da177e4 LT	121
	122	/*
	123	* Oops. The kernel tried to access some page that wasn't present.
	124	*/
	125	static void
	126	__do_kernel_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
	127	struct pt_regs *regs)
	128	{
	129	/*
	130	* Are we prepared to handle this kernel fault?
	131	*/
	132	if (fixup_exception(regs))
	133	return;
	134
	135	/*
	136	* No handler, we'll have to terminate things with extreme prejudice.
	137	*/
	138	bust_spinlocks(1);
	139	printk(KERN_ALERT
	140	"Unable to handle kernel %s at virtual address %08lx\n",
	141	(addr < PAGE_SIZE) ? "NULL pointer dereference" :
	142	"paging request", addr);
	143
	144	show_pte(mm, addr);
	145	die("Oops", regs, fsr);
	146	bust_spinlocks(0);
	147	do_exit(SIGKILL);
	148	}
	149
	150	/*
	151	* Something tried to access memory that isn't in our memory map..
	152	* User mode accesses just cause a SIGSEGV
	153	*/
	154	static void
	155	__do_user_fault(struct task_struct *tsk, unsigned long addr,
2d137c24 AM	156	unsigned int fsr, unsigned int sig, int code,
2d137c24 AM	157	struct pt_regs *regs)
1da177e4 LT	158	{
	159	struct siginfo si;
	160
	161	#ifdef CONFIG_DEBUG_USER
	162	if (user_debug & UDBG_SEGV) {
2d137c24 AM	163	printk(KERN_DEBUG "%s: unhandled page fault (%d) at 0x%08lx, code 0x%03x\n",
2d137c24 AM	164	tsk->comm, sig, addr, fsr);
1da177e4 LT	165	show_pte(tsk->mm, addr);
	166	show_regs(regs);
	167	}
	168	#endif
	169
	170	tsk->thread.address = addr;
	171	tsk->thread.error_code = fsr;
	172	tsk->thread.trap_no = 14;
2d137c24	173	si.si_signo = sig;
1da177e4 LT	174	si.si_errno = 0;
	175	si.si_code = code;
	176	si.si_addr = (void __user *)addr;
2d137c24	177	force_sig_info(sig, &si, tsk);
1da177e4 LT	178	}
1da177e4 LT	179
e5beac37	180	void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
1da177e4	181	{
e5beac37 RK	182	struct task_struct *tsk = current;
	183	struct mm_struct *mm = tsk->active_mm;
	184
1da177e4 LT	185	/*
	186	* If we are in kernel mode at this point, we
	187	* have no context to handle this fault with.
	188	*/
	189	if (user_mode(regs))
2d137c24	190	__do_user_fault(tsk, addr, fsr, SIGSEGV, SEGV_MAPERR, regs);
1da177e4 LT	191	else
	192	__do_kernel_fault(mm, addr, fsr, regs);
	193	}
	194
09529f7a	195	#ifdef CONFIG_MMU
5c72fc5c NP	196	#define VM_FAULT_BADMAP 0x010000
5c72fc5c NP	197	#define VM_FAULT_BADACCESS 0x020000
1da177e4	198
d374bf14 RK	199	/*
	200	* Check that the permissions on the VMA allow for the fault which occurred.
	201	* If we encountered a write fault, we must have write permission, otherwise
	202	* we allow any permission.
	203	*/
	204	static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
	205	{
	206	unsigned int mask = VM_READ \| VM_WRITE \| VM_EXEC;
	207
	208	if (fsr & FSR_WRITE)
	209	mask = VM_WRITE;
df297bf6 RK	210	if (fsr & FSR_LNX_PF)
df297bf6 RK	211	mask = VM_EXEC;
d374bf14 RK	212
	213	return vma->vm_flags & mask ? false : true;
	214	}
	215
	216	static int __kprobes
1da177e4 LT	217	__do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
	218	struct task_struct *tsk)
	219	{
	220	struct vm_area_struct *vma;
d374bf14	221	int fault;
1da177e4 LT	222
	223	vma = find_vma(mm, addr);
	224	fault = VM_FAULT_BADMAP;
d374bf14	225	if (unlikely(!vma))
1da177e4	226	goto out;
d374bf14	227	if (unlikely(vma->vm_start > addr))
1da177e4 LT	228	goto check_stack;
	229
	230	/*
	231	* Ok, we have a good vm_area for this
	232	* memory access, so we can handle it.
	233	*/
	234	good_area:
d374bf14 RK	235	if (access_error(fsr, vma)) {
d374bf14 RK	236	fault = VM_FAULT_BADACCESS;
1da177e4	237	goto out;
d374bf14	238	}
1da177e4 LT	239
1da177e4 LT	240	/*
b42c6344 RK	241	* If for any reason at all we couldn't handle the fault, make
b42c6344 RK	242	* sure we exit gracefully rather than endlessly redo the fault.
1da177e4	243	*/
c88d6aa7	244	fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, (fsr & FSR_WRITE) ? FAULT_FLAG_WRITE : 0);
b42c6344 RK	245	if (unlikely(fault & VM_FAULT_ERROR))
b42c6344 RK	246	return fault;
83c54070	247	if (fault & VM_FAULT_MAJOR)
1da177e4	248	tsk->maj_flt++;
83c54070	249	else
1da177e4	250	tsk->min_flt++;
83c54070	251	return fault;
1da177e4	252
1da177e4 LT	253	check_stack:
	254	if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
	255	goto good_area;
	256	out:
	257	return fault;
	258	}
	259
785d3cd2	260	static int __kprobes
1da177e4 LT	261	do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
	262	{
	263	struct task_struct *tsk;
	264	struct mm_struct *mm;
2d137c24	265	int fault, sig, code;
1da177e4	266
25ce1dd7 NP	267	if (notify_page_fault(regs, fsr))
	268	return 0;
	269
1da177e4 LT	270	tsk = current;
	271	mm = tsk->mm;
	272
	273	/*
	274	* If we're in an interrupt or have no user
	275	* context, we must not take the fault..
	276	*/
6edaf68a	277	if (in_atomic() \|\| !mm)
1da177e4 LT	278	goto no_context;
1da177e4 LT	279
840ff6a4 RK	280	/*
	281	* As per x86, we may deadlock here. However, since the kernel only
	282	* validly references user space from well defined areas of the code,
	283	* we can bug out early if this is from code which shouldn't.
	284	*/
	285	if (!down_read_trylock(&mm->mmap_sem)) {
	286	if (!user_mode(regs) && !search_exception_tables(regs->ARM_pc))
	287	goto no_context;
	288	down_read(&mm->mmap_sem);
bf456992 RK	289	} else {
	290	/*
	291	* The above down_read_trylock() might have succeeded in
	292	* which case, we'll have missed the might_sleep() from
	293	* down_read()
	294	*/
	295	might_sleep();
1d212712 ID	296	#ifdef CONFIG_DEBUG_VM
	297	if (!user_mode(regs) &&
	298	!search_exception_tables(regs->ARM_pc))
	299	goto no_context;
	300	#endif
840ff6a4 RK	301	}
840ff6a4 RK	302
1da177e4 LT	303	fault = __do_page_fault(mm, addr, fsr, tsk);
	304	up_read(&mm->mmap_sem);
	305
7ada189f JI	306	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, addr);
	307	if (fault & VM_FAULT_MAJOR)
	308	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 0, regs, addr);
	309	else if (fault & VM_FAULT_MINOR)
	310	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 0, regs, addr);
	311
1da177e4	312	/*
ff2afb9d	313	* Handle the "normal" case first - VM_FAULT_MAJOR / VM_FAULT_MINOR
1da177e4	314	*/
5c72fc5c	315	if (likely(!(fault & (VM_FAULT_ERROR \| VM_FAULT_BADMAP \| VM_FAULT_BADACCESS))))
1da177e4 LT	316	return 0;
1da177e4 LT	317
b42c6344 RK	318	if (fault & VM_FAULT_OOM) {
	319	/*
	320	* We ran out of memory, call the OOM killer, and return to
	321	* userspace (which will retry the fault, or kill us if we
	322	* got oom-killed)
	323	*/
	324	pagefault_out_of_memory();
	325	return 0;
	326	}
	327
1da177e4 LT	328	/*
	329	* If we are in kernel mode at this point, we
	330	* have no context to handle this fault with.
	331	*/
	332	if (!user_mode(regs))
	333	goto no_context;
	334
83c54070	335	if (fault & VM_FAULT_SIGBUS) {
2d137c24 AM	336	/*
	337	* We had some memory, but were unable to
	338	* successfully fix up this page fault.
	339	*/
	340	sig = SIGBUS;
	341	code = BUS_ADRERR;
83c54070	342	} else {
2d137c24 AM	343	/*
	344	* Something tried to access memory that
	345	* isn't in our memory map..
	346	*/
	347	sig = SIGSEGV;
	348	code = fault == VM_FAULT_BADACCESS ?
	349	SEGV_ACCERR : SEGV_MAPERR;
1da177e4	350	}
1da177e4	351
2d137c24 AM	352	__do_user_fault(tsk, addr, fsr, sig, code, regs);
2d137c24 AM	353	return 0;
1da177e4 LT	354
	355	no_context:
	356	__do_kernel_fault(mm, addr, fsr, regs);
	357	return 0;
	358	}
09529f7a CM	359	#else /* CONFIG_MMU */
	360	static int
	361	do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
	362	{
	363	return 0;
	364	}
	365	#endif /* CONFIG_MMU */
1da177e4 LT	366
	367	/*
	368	* First Level Translation Fault Handler
	369	*
	370	* We enter here because the first level page table doesn't contain
	371	* a valid entry for the address.
	372	*
	373	* If the address is in kernel space (>= TASK_SIZE), then we are
	374	* probably faulting in the vmalloc() area.
	375	*
	376	* If the init_task's first level page tables contains the relevant
	377	* entry, we copy the it to this task. If not, we send the process
	378	* a signal, fixup the exception, or oops the kernel.
	379	*
	380	* NOTE! We MUST NOT take any locks for this case. We may be in an
	381	* interrupt or a critical region, and should only copy the information
	382	* from the master page table, nothing more.
	383	*/
09529f7a	384	#ifdef CONFIG_MMU
785d3cd2	385	static int __kprobes
1da177e4 LT	386	do_translation_fault(unsigned long addr, unsigned int fsr,
	387	struct pt_regs *regs)
	388	{
1da177e4 LT	389	unsigned int index;
	390	pgd_t pgd, pgd_k;
	391	pmd_t pmd, pmd_k;
	392
	393	if (addr < TASK_SIZE)
	394	return do_page_fault(addr, fsr, regs);
	395
5e27fb78 A	396	if (user_mode(regs))
	397	goto bad_area;
	398
1da177e4 LT	399	index = pgd_index(addr);
	400
	401	/*
	402	* FIXME: CP15 C1 is write only on ARMv3 architectures.
	403	*/
	404	pgd = cpu_get_pgd() + index;
	405	pgd_k = init_mm.pgd + index;
	406
	407	if (pgd_none(*pgd_k))
	408	goto bad_area;
	409
	410	if (!pgd_present(*pgd))
	411	set_pgd(pgd, *pgd_k);
	412
	413	pmd_k = pmd_offset(pgd_k, addr);
	414	pmd = pmd_offset(pgd, addr);
	415
	416	if (pmd_none(*pmd_k))
	417	goto bad_area;
	418
	419	copy_pmd(pmd, pmd_k);
	420	return 0;
	421
	422	bad_area:
e5beac37	423	do_bad_area(addr, fsr, regs);
1da177e4 LT	424	return 0;
1da177e4 LT	425	}
09529f7a CM	426	#else /* CONFIG_MMU */
	427	static int
	428	do_translation_fault(unsigned long addr, unsigned int fsr,
	429	struct pt_regs *regs)
	430	{
	431	return 0;
	432	}
	433	#endif /* CONFIG_MMU */
1da177e4 LT	434
	435	/*
	436	* Some section permission faults need to be handled gracefully.
	437	* They can happen due to a __{get,put}_user during an oops.
	438	*/
	439	static int
	440	do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
	441	{
e5beac37	442	do_bad_area(addr, fsr, regs);
1da177e4 LT	443	return 0;
	444	}
	445
	446	/*
	447	* This abort handler always returns "fault".
	448	*/
	449	static int
	450	do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
	451	{
	452	return 1;
	453	}
	454
	455	static struct fsr_info {
	456	int (fn)(unsigned long addr, unsigned int fsr, struct pt_regs regs);
	457	int sig;
cfb0810e	458	int code;
1da177e4 LT	459	const char *name;
	460	} fsr_info[] = {
	461	/*
	462	* The following are the standard ARMv3 and ARMv4 aborts. ARMv5
	463	* defines these to be "precise" aborts.
	464	*/
cfb0810e	465	{ do_bad, SIGSEGV, 0, "vector exception" },
3dc91aff	466	{ do_bad, SIGBUS, BUS_ADRALN, "alignment exception" },
cfb0810e	467	{ do_bad, SIGKILL, 0, "terminal exception" },
3dc91aff	468	{ do_bad, SIGBUS, BUS_ADRALN, "alignment exception" },
8c0b742c KS	469	/* Do we need runtime check ? */
8c0b742c KS	470	#if __LINUX_ARM_ARCH__ < 6
cfb0810e	471	{ do_bad, SIGBUS, 0, "external abort on linefetch" },
8c0b742c KS	472	#else
	473	{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "I-cache maintenance fault" },
	474	#endif
cfb0810e RK	475	{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "section translation fault" },
	476	{ do_bad, SIGBUS, 0, "external abort on linefetch" },
	477	{ do_page_fault, SIGSEGV, SEGV_MAPERR, "page translation fault" },
	478	{ do_bad, SIGBUS, 0, "external abort on non-linefetch" },
	479	{ do_bad, SIGSEGV, SEGV_ACCERR, "section domain fault" },
	480	{ do_bad, SIGBUS, 0, "external abort on non-linefetch" },
	481	{ do_bad, SIGSEGV, SEGV_ACCERR, "page domain fault" },
	482	{ do_bad, SIGBUS, 0, "external abort on translation" },
	483	{ do_sect_fault, SIGSEGV, SEGV_ACCERR, "section permission fault" },
	484	{ do_bad, SIGBUS, 0, "external abort on translation" },
	485	{ do_page_fault, SIGSEGV, SEGV_ACCERR, "page permission fault" },
1da177e4 LT	486	/*
	487	* The following are "imprecise" aborts, which are signalled by bit
	488	* 10 of the FSR, and may not be recoverable. These are only
	489	* supported if the CPU abort handler supports bit 10.
	490	*/
cfb0810e RK	491	{ do_bad, SIGBUS, 0, "unknown 16" },
	492	{ do_bad, SIGBUS, 0, "unknown 17" },
	493	{ do_bad, SIGBUS, 0, "unknown 18" },
	494	{ do_bad, SIGBUS, 0, "unknown 19" },
	495	{ do_bad, SIGBUS, 0, "lock abort" }, /* xscale */
	496	{ do_bad, SIGBUS, 0, "unknown 21" },
	497	{ do_bad, SIGBUS, BUS_OBJERR, "imprecise external abort" }, /* xscale */
	498	{ do_bad, SIGBUS, 0, "unknown 23" },
	499	{ do_bad, SIGBUS, 0, "dcache parity error" }, /* xscale */
	500	{ do_bad, SIGBUS, 0, "unknown 25" },
	501	{ do_bad, SIGBUS, 0, "unknown 26" },
	502	{ do_bad, SIGBUS, 0, "unknown 27" },
	503	{ do_bad, SIGBUS, 0, "unknown 28" },
	504	{ do_bad, SIGBUS, 0, "unknown 29" },
	505	{ do_bad, SIGBUS, 0, "unknown 30" },
	506	{ do_bad, SIGBUS, 0, "unknown 31" }
1da177e4 LT	507	};
	508
	509	void __init
	510	hook_fault_code(int nr, int (fn)(unsigned long, unsigned int, struct pt_regs ),
6338a6aa	511	int sig, int code, const char *name)
1da177e4	512	{
6338a6aa KS	513	if (nr < 0 \|\| nr >= ARRAY_SIZE(fsr_info))
	514	BUG();
	515
	516	fsr_info[nr].fn = fn;
	517	fsr_info[nr].sig = sig;
	518	fsr_info[nr].code = code;
	519	fsr_info[nr].name = name;
1da177e4 LT	520	}
	521
	522	/*
	523	* Dispatch a data abort to the relevant handler.
	524	*/
7ab3f8d5	525	asmlinkage void __exception
1da177e4 LT	526	do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
1da177e4 LT	527	{
c88d6aa7	528	const struct fsr_info *inf = fsr_info + fsr_fs(fsr);
cfb0810e	529	struct siginfo info;
1da177e4	530
df297bf6	531	if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
1da177e4 LT	532	return;
	533
	534	printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
	535	inf->name, fsr, addr);
cfb0810e RK	536
	537	info.si_signo = inf->sig;
	538	info.si_errno = 0;
	539	info.si_code = inf->code;
	540	info.si_addr = (void __user *)addr;
1eeb66a1	541	arm_notify_die("", regs, &info, fsr, 0);
1da177e4 LT	542	}
1da177e4 LT	543
d25ef8b8 KS	544
	545	static struct fsr_info ifsr_info[] = {
	546	{ do_bad, SIGBUS, 0, "unknown 0" },
	547	{ do_bad, SIGBUS, 0, "unknown 1" },
	548	{ do_bad, SIGBUS, 0, "debug event" },
	549	{ do_bad, SIGSEGV, SEGV_ACCERR, "section access flag fault" },
	550	{ do_bad, SIGBUS, 0, "unknown 4" },
	551	{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "section translation fault" },
	552	{ do_bad, SIGSEGV, SEGV_ACCERR, "page access flag fault" },
	553	{ do_page_fault, SIGSEGV, SEGV_MAPERR, "page translation fault" },
	554	{ do_bad, SIGBUS, 0, "external abort on non-linefetch" },
	555	{ do_bad, SIGSEGV, SEGV_ACCERR, "section domain fault" },
	556	{ do_bad, SIGBUS, 0, "unknown 10" },
	557	{ do_bad, SIGSEGV, SEGV_ACCERR, "page domain fault" },
	558	{ do_bad, SIGBUS, 0, "external abort on translation" },
	559	{ do_sect_fault, SIGSEGV, SEGV_ACCERR, "section permission fault" },
	560	{ do_bad, SIGBUS, 0, "external abort on translation" },
	561	{ do_page_fault, SIGSEGV, SEGV_ACCERR, "page permission fault" },
	562	{ do_bad, SIGBUS, 0, "unknown 16" },
	563	{ do_bad, SIGBUS, 0, "unknown 17" },
	564	{ do_bad, SIGBUS, 0, "unknown 18" },
	565	{ do_bad, SIGBUS, 0, "unknown 19" },
	566	{ do_bad, SIGBUS, 0, "unknown 20" },
	567	{ do_bad, SIGBUS, 0, "unknown 21" },
	568	{ do_bad, SIGBUS, 0, "unknown 22" },
	569	{ do_bad, SIGBUS, 0, "unknown 23" },
	570	{ do_bad, SIGBUS, 0, "unknown 24" },
	571	{ do_bad, SIGBUS, 0, "unknown 25" },
	572	{ do_bad, SIGBUS, 0, "unknown 26" },
	573	{ do_bad, SIGBUS, 0, "unknown 27" },
	574	{ do_bad, SIGBUS, 0, "unknown 28" },
	575	{ do_bad, SIGBUS, 0, "unknown 29" },
	576	{ do_bad, SIGBUS, 0, "unknown 30" },
	577	{ do_bad, SIGBUS, 0, "unknown 31" },
	578	};
	579
7ab3f8d5	580	asmlinkage void __exception
4fb28474	581	do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs)
1da177e4	582	{
d25ef8b8 KS	583	const struct fsr_info *inf = ifsr_info + fsr_fs(ifsr);
	584	struct siginfo info;
	585
	586	if (!inf->fn(addr, ifsr \| FSR_LNX_PF, regs))
	587	return;
	588
	589	printk(KERN_ALERT "Unhandled prefetch abort: %s (0x%03x) at 0x%08lx\n",
	590	inf->name, ifsr, addr);
	591
	592	info.si_signo = inf->sig;
	593	info.si_errno = 0;
	594	info.si_code = inf->code;
	595	info.si_addr = (void __user *)addr;
	596	arm_notify_die("", regs, &info, ifsr, 0);
1da177e4 LT	597	}
1da177e4 LT	598