[mirror_ubuntu-bionic-kernel.git] / arch / parisc / mm / fault.c

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 *
 * Copyright (C) 1995, 1996, 1997, 1998 by Ralf Baechle
 * Copyright 1999 SuSE GmbH (Philipp Rumpf, prumpf@tux.org)
 * Copyright 1999 Hewlett Packard Co.
 *
 */

#include <linux/mm.h>
#include <linux/ptrace.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/interrupt.h>
#include <linux/extable.h>
#include <linux/uaccess.h>

#include <asm/traps.h>

/* Various important other fields */
#define bit22set(x)		(x & 0x00000200)
#define bits23_25set(x)		(x & 0x000001c0)
#define isGraphicsFlushRead(x)	((x & 0xfc003fdf) == 0x04001a80)
				/* extended opcode is 0x6a */

#define BITSSET		0x1c0	/* for identifying LDCW */


int show_unhandled_signals = 1;

/*
 * parisc_acctyp(unsigned int inst) --
 *    Given a PA-RISC memory access instruction, determine if the
 *    the instruction would perform a memory read or memory write
 *    operation.
 *
 *    This function assumes that the given instruction is a memory access
 *    instruction (i.e. you should really only call it if you know that
 *    the instruction has generated some sort of a memory access fault).
 *
 * Returns:
 *   VM_READ  if read operation
 *   VM_WRITE if write operation
 *   VM_EXEC  if execute operation
 */
static unsigned long
parisc_acctyp(unsigned long code, unsigned int inst)
{
	if (code == 6 || code == 16)
	    return VM_EXEC;

	switch (inst & 0xf0000000) {
	case 0x40000000: /* load */
	case 0x50000000: /* new load */
		return VM_READ;

	case 0x60000000: /* store */
	case 0x70000000: /* new store */
		return VM_WRITE;

	case 0x20000000: /* coproc */
	case 0x30000000: /* coproc2 */
		if (bit22set(inst))
			return VM_WRITE;

	case 0x0: /* indexed/memory management */
		if (bit22set(inst)) {
			/*
			 * Check for the 'Graphics Flush Read' instruction.
			 * It resembles an FDC instruction, except for bits
			 * 20 and 21. Any combination other than zero will
			 * utilize the block mover functionality on some
			 * older PA-RISC platforms.  The case where a block
			 * move is performed from VM to graphics IO space
			 * should be treated as a READ.
			 *
			 * The significance of bits 20,21 in the FDC
			 * instruction is:
			 *
			 *   00  Flush data cache (normal instruction behavior)
			 *   01  Graphics flush write  (IO space -> VM)
			 *   10  Graphics flush read   (VM -> IO space)
			 *   11  Graphics flush read/write (VM <-> IO space)
			 */
			if (isGraphicsFlushRead(inst))
				return VM_READ;
			return VM_WRITE;
		} else {
			/*
			 * Check for LDCWX and LDCWS (semaphore instructions).
			 * If bits 23 through 25 are all 1's it is one of
			 * the above two instructions and is a write.
			 *
			 * Note: With the limited bits we are looking at,
			 * this will also catch PROBEW and PROBEWI. However,
			 * these should never get in here because they don't
			 * generate exceptions of the type:
			 *   Data TLB miss fault/data page fault
			 *   Data memory protection trap
			 */
			if (bits23_25set(inst) == BITSSET)
				return VM_WRITE;
		}
		return VM_READ; /* Default */
	}
	return VM_READ; /* Default */
}

#undef bit22set
#undef bits23_25set
#undef isGraphicsFlushRead
#undef BITSSET


#if 0
/* This is the treewalk to find a vma which is the highest that has
 * a start < addr.  We're using find_vma_prev instead right now, but
 * we might want to use this at some point in the future.  Probably
 * not, but I want it committed to CVS so I don't lose it :-)
 */
			while (tree != vm_avl_empty) {
				if (tree->vm_start > addr) {
					tree = tree->vm_avl_left;
				} else {
					prev = tree;
					if (prev->vm_next == NULL)
						break;
					if (prev->vm_next->vm_start > addr)
						break;
					tree = tree->vm_avl_right;
				}
			}
#endif

int fixup_exception(struct pt_regs *regs)
{
	const struct exception_table_entry *fix;

	fix = search_exception_tables(regs->iaoq[0]);
	if (fix) {
		/*
		 * Fix up get_user() and put_user().
		 * ASM_EXCEPTIONTABLE_ENTRY_EFAULT() sets the least-significant
		 * bit in the relative address of the fixup routine to indicate
		 * that %r8 should be loaded with -EFAULT to report a userspace
		 * access error.
		 */
		if (fix->fixup & 1) {
			regs->gr[8] = -EFAULT;

			/* zero target register for get_user() */
			if (parisc_acctyp(0, regs->iir) == VM_READ) {
				int treg = regs->iir & 0x1f;
				BUG_ON(treg == 0);
				regs->gr[treg] = 0;
			}
		}

		regs->iaoq[0] = (unsigned long)&fix->fixup + fix->fixup;
		regs->iaoq[0] &= ~3;
		/*
		 * NOTE: In some cases the faulting instruction
		 * may be in the delay slot of a branch. We
		 * don't want to take the branch, so we don't
		 * increment iaoq[1], instead we set it to be
		 * iaoq[0]+4, and clear the B bit in the PSW
		 */
		regs->iaoq[1] = regs->iaoq[0] + 4;
		regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */

		return 1;
	}

	return 0;
}

/*
 * parisc hardware trap list
 *
 * Documented in section 3 "Addressing and Access Control" of the
 * "PA-RISC 1.1 Architecture and Instruction Set Reference Manual"
 * https://parisc.wiki.kernel.org/index.php/File:Pa11_acd.pdf
 *
 * For implementation see handle_interruption() in traps.c
 */
static const char * const trap_description[] = {
	[1] "High-priority machine check (HPMC)",
	[2] "Power failure interrupt",
	[3] "Recovery counter trap",
	[5] "Low-priority machine check",
	[6] "Instruction TLB miss fault",
	[7] "Instruction access rights / protection trap",
	[8] "Illegal instruction trap",
	[9] "Break instruction trap",
	[10] "Privileged operation trap",
	[11] "Privileged register trap",
	[12] "Overflow trap",
	[13] "Conditional trap",
	[14] "FP Assist Exception trap",
	[15] "Data TLB miss fault",
	[16] "Non-access ITLB miss fault",
	[17] "Non-access DTLB miss fault",
	[18] "Data memory protection/unaligned access trap",
	[19] "Data memory break trap",
	[20] "TLB dirty bit trap",
	[21] "Page reference trap",
	[22] "Assist emulation trap",
	[25] "Taken branch trap",
	[26] "Data memory access rights trap",
	[27] "Data memory protection ID trap",
	[28] "Unaligned data reference trap",
};

const char *trap_name(unsigned long code)
{
	const char *t = NULL;

	if (code < ARRAY_SIZE(trap_description))
		t = trap_description[code];

	return t ? t : "Unknown trap";
}

/*
 * Print out info about fatal segfaults, if the show_unhandled_signals
 * sysctl is set:
 */
static inline void
show_signal_msg(struct pt_regs *regs, unsigned long code,
		unsigned long address, struct task_struct *tsk,
		struct vm_area_struct *vma)
{
	if (!unhandled_signal(tsk, SIGSEGV))
		return;

	if (!printk_ratelimit())
		return;

	pr_warn("\n");
	pr_warn("do_page_fault() command='%s' type=%lu address=0x%08lx",
	    tsk->comm, code, address);
	print_vma_addr(KERN_CONT " in ", regs->iaoq[0]);

	pr_cont("\ntrap #%lu: %s%c", code, trap_name(code),
		vma ? ',':'\n');

	if (vma)
		pr_cont(" vm_start = 0x%08lx, vm_end = 0x%08lx\n",
			vma->vm_start, vma->vm_end);

	show_regs(regs);
}

void do_page_fault(struct pt_regs *regs, unsigned long code,
			      unsigned long address)
{
	struct vm_area_struct *vma, *prev_vma;
	struct task_struct *tsk;
	struct mm_struct *mm;
	unsigned long acc_type;
	int fault;
	unsigned int flags;

	if (faulthandler_disabled())
		goto no_context;

	tsk = current;
	mm = tsk->mm;
	if (!mm)
		goto no_context;

	flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
	if (user_mode(regs))
		flags |= FAULT_FLAG_USER;

	acc_type = parisc_acctyp(code, regs->iir);
	if (acc_type & VM_WRITE)
		flags |= FAULT_FLAG_WRITE;
retry:
	down_read(&mm->mmap_sem);
	vma = find_vma_prev(mm, address, &prev_vma);
	if (!vma || address < vma->vm_start)
		goto check_expansion;
/*
 * Ok, we have a good vm_area for this memory access. We still need to
 * check the access permissions.
 */

good_area:

	if ((vma->vm_flags & acc_type) != acc_type)
		goto bad_area;

	/*
	 * If for any reason at all we couldn't handle the fault, make
	 * sure we exit gracefully rather than endlessly redo the
	 * fault.
	 */

	fault = handle_mm_fault(vma, address, flags);

	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
		return;

	if (unlikely(fault & VM_FAULT_ERROR)) {
		/*
		 * We hit a shared mapping outside of the file, or some
		 * other thing happened to us that made us unable to
		 * handle the page fault gracefully.
		 */
		if (fault & VM_FAULT_OOM)
			goto out_of_memory;
		else if (fault & VM_FAULT_SIGSEGV)
			goto bad_area;
		else if (fault & VM_FAULT_SIGBUS)
			goto bad_area;
		BUG();
	}
	if (flags & FAULT_FLAG_ALLOW_RETRY) {
		if (fault & VM_FAULT_MAJOR)
			current->maj_flt++;
		else
			current->min_flt++;
		if (fault & VM_FAULT_RETRY) {
			flags &= ~FAULT_FLAG_ALLOW_RETRY;

			/*
			 * No need to up_read(&mm->mmap_sem) as we would
			 * have already released it in __lock_page_or_retry
			 * in mm/filemap.c.
			 */

			goto retry;
		}
	}
	up_read(&mm->mmap_sem);
	return;

check_expansion:
	vma = prev_vma;
	if (vma && (expand_stack(vma, address) == 0))
		goto good_area;

/*
 * Something tried to access memory that isn't in our memory map..
 */
bad_area:
	up_read(&mm->mmap_sem);

	if (user_mode(regs)) {
		struct siginfo si;

		show_signal_msg(regs, code, address, tsk, vma);

		switch (code) {
		case 15:	/* Data TLB miss fault/Data page fault */
			/* send SIGSEGV when outside of vma */
			if (!vma ||
			    address < vma->vm_start || address > vma->vm_end) {
				si.si_signo = SIGSEGV;
				si.si_code = SEGV_MAPERR;
				break;
			}

			/* send SIGSEGV for wrong permissions */
			if ((vma->vm_flags & acc_type) != acc_type) {
				si.si_signo = SIGSEGV;
				si.si_code = SEGV_ACCERR;
				break;
			}

			/* probably address is outside of mapped file */
			/* fall through */
		case 17:	/* NA data TLB miss / page fault */
		case 18:	/* Unaligned access - PCXS only */
			si.si_signo = SIGBUS;
			si.si_code = (code == 18) ? BUS_ADRALN : BUS_ADRERR;
			break;
		case 16:	/* Non-access instruction TLB miss fault */
		case 26:	/* PCXL: Data memory access rights trap */
		default:
			si.si_signo = SIGSEGV;
			si.si_code = (code == 26) ? SEGV_ACCERR : SEGV_MAPERR;
			break;
		}
		si.si_errno = 0;
		si.si_addr = (void __user *) address;
		force_sig_info(si.si_signo, &si, current);
		return;
	}

no_context:

	if (!user_mode(regs) && fixup_exception(regs)) {
		return;
	}

	parisc_terminate("Bad Address (null pointer deref?)", regs, code, address);

  out_of_memory:
	up_read(&mm->mmap_sem);
	if (!user_mode(regs))
		goto no_context;
	pagefault_out_of_memory();
}
Commit	Line	Data
071327ec	1	/*
1da177e4 LT	2	* This file is subject to the terms and conditions of the GNU General Public
	3	* License. See the file "COPYING" in the main directory of this archive
	4	* for more details.
	5	*
	6	*
	7	* Copyright (C) 1995, 1996, 1997, 1998 by Ralf Baechle
	8	* Copyright 1999 SuSE GmbH (Philipp Rumpf, prumpf@tux.org)
	9	* Copyright 1999 Hewlett Packard Co.
	10	*
	11	*/
	12
	13	#include <linux/mm.h>
	14	#include <linux/ptrace.h>
	15	#include <linux/sched.h>
b17b0153	16	#include <linux/sched/debug.h>
1da177e4	17	#include <linux/interrupt.h>
a38671d6	18	#include <linux/extable.h>
70ffdb93	19	#include <linux/uaccess.h>
1da177e4	20
1da177e4 LT	21	#include <asm/traps.h>
1da177e4 LT	22
1da177e4 LT	23	/* Various important other fields */
	24	#define bit22set(x) (x & 0x00000200)
	25	#define bits23_25set(x) (x & 0x000001c0)
	26	#define isGraphicsFlushRead(x) ((x & 0xfc003fdf) == 0x04001a80)
	27	/* extended opcode is 0x6a */
	28
	29	#define BITSSET 0x1c0 /* for identifying LDCW */
	30
	31
fef47e2a HD	32	int show_unhandled_signals = 1;
fef47e2a HD	33
1da177e4 LT	34	/*
	35	* parisc_acctyp(unsigned int inst) --
	36	* Given a PA-RISC memory access instruction, determine if the
	37	* the instruction would perform a memory read or memory write
	38	* operation.
	39	*
	40	* This function assumes that the given instruction is a memory access
	41	* instruction (i.e. you should really only call it if you know that
	42	* the instruction has generated some sort of a memory access fault).
	43	*
	44	* Returns:
	45	* VM_READ if read operation
	46	* VM_WRITE if write operation
	47	* VM_EXEC if execute operation
	48	*/
	49	static unsigned long
	50	parisc_acctyp(unsigned long code, unsigned int inst)
	51	{
	52	if (code == 6 \|\| code == 16)
	53	return VM_EXEC;
	54
	55	switch (inst & 0xf0000000) {
	56	case 0x40000000: /* load */
	57	case 0x50000000: /* new load */
	58	return VM_READ;
	59
	60	case 0x60000000: /* store */
	61	case 0x70000000: /* new store */
	62	return VM_WRITE;
	63
	64	case 0x20000000: /* coproc */
	65	case 0x30000000: /* coproc2 */
	66	if (bit22set(inst))
	67	return VM_WRITE;
	68
	69	case 0x0: /* indexed/memory management */
	70	if (bit22set(inst)) {
	71	/*
	72	* Check for the 'Graphics Flush Read' instruction.
	73	* It resembles an FDC instruction, except for bits
	74	* 20 and 21. Any combination other than zero will
	75	* utilize the block mover functionality on some
	76	* older PA-RISC platforms. The case where a block
	77	* move is performed from VM to graphics IO space
	78	* should be treated as a READ.
	79	*
	80	* The significance of bits 20,21 in the FDC
	81	* instruction is:
	82	*
	83	* 00 Flush data cache (normal instruction behavior)
	84	* 01 Graphics flush write (IO space -> VM)
	85	* 10 Graphics flush read (VM -> IO space)
	86	* 11 Graphics flush read/write (VM <-> IO space)
	87	*/
	88	if (isGraphicsFlushRead(inst))
	89	return VM_READ;
	90	return VM_WRITE;
	91	} else {
	92	/*
	93	* Check for LDCWX and LDCWS (semaphore instructions).
	94	* If bits 23 through 25 are all 1's it is one of
	95	* the above two instructions and is a write.
	96	*
	97	* Note: With the limited bits we are looking at,
98	* this will also catch PROBEW and PROBEWI. However,
99	* these should never get in here because they don't
100	* generate exceptions of the type:
101	* Data TLB miss fault/data page fault
102	* Data memory protection trap
103	*/
104	if (bits23_25set(inst) == BITSSET)
105	return VM_WRITE;
106	}
107	return VM_READ; /* Default */
108	}
109	return VM_READ; /* Default */
110	}
111
112	#undef bit22set
113	#undef bits23_25set
114	#undef isGraphicsFlushRead
115	#undef BITSSET
116
117
118	#if 0
119	/* This is the treewalk to find a vma which is the highest that has
120	* a start < addr. We're using find_vma_prev instead right now, but
121	* we might want to use this at some point in the future. Probably
122	* not, but I want it committed to CVS so I don't lose it :-)
123	*/
124	while (tree != vm_avl_empty) {
125	if (tree->vm_start > addr) {
126	tree = tree->vm_avl_left;
127	} else {
128	prev = tree;
129	if (prev->vm_next == NULL)
130	break;
131	if (prev->vm_next->vm_start > addr)
132	break;
133	tree = tree->vm_avl_right;
134	}
135	}
136	#endif
137
c61c25eb KM	138	int fixup_exception(struct pt_regs *regs)
	139	{
	140	const struct exception_table_entry *fix;
	141
	142	fix = search_exception_tables(regs->iaoq[0]);
	143	if (fix) {
d19f5e41 HD	144	/*
	145	* Fix up get_user() and put_user().
	146	* ASM_EXCEPTIONTABLE_ENTRY_EFAULT() sets the least-significant
	147	* bit in the relative address of the fixup routine to indicate
	148	* that %r8 should be loaded with -EFAULT to report a userspace
	149	* access error.
	150	*/
	151	if (fix->fixup & 1) {
	152	regs->gr[8] = -EFAULT;
	153
	154	/* zero target register for get_user() */
	155	if (parisc_acctyp(0, regs->iir) == VM_READ) {
	156	int treg = regs->iir & 0x1f;
b752c7b2	157	BUG_ON(treg == 0);
d19f5e41 HD	158	regs->gr[treg] = 0;
	159	}
	160	}
	161
0de79858 HD	162	regs->iaoq[0] = (unsigned long)&fix->fixup + fix->fixup;
0de79858 HD	163	regs->iaoq[0] &= ~3;
c61c25eb KM	164	/*
	165	* NOTE: In some cases the faulting instruction
	166	* may be in the delay slot of a branch. We
	167	* don't want to take the branch, so we don't
	168	* increment iaoq[1], instead we set it to be
	169	* iaoq[0]+4, and clear the B bit in the PSW
	170	*/
	171	regs->iaoq[1] = regs->iaoq[0] + 4;
	172	regs->gr[0] &= ~PSW_B; /* IPSW in gr[0] */
	173
	174	return 1;
	175	}
	176
	177	return 0;
	178	}
	179
b391667e HD	180	/*
	181	* parisc hardware trap list
	182	*
	183	* Documented in section 3 "Addressing and Access Control" of the
	184	* "PA-RISC 1.1 Architecture and Instruction Set Reference Manual"
	185	* https://parisc.wiki.kernel.org/index.php/File:Pa11_acd.pdf
	186	*
	187	* For implementation see handle_interruption() in traps.c
	188	*/
	189	static const char * const trap_description[] = {
	190	[1] "High-priority machine check (HPMC)",
	191	[2] "Power failure interrupt",
	192	[3] "Recovery counter trap",
	193	[5] "Low-priority machine check",
	194	[6] "Instruction TLB miss fault",
	195	[7] "Instruction access rights / protection trap",
	196	[8] "Illegal instruction trap",
	197	[9] "Break instruction trap",
	198	[10] "Privileged operation trap",
	199	[11] "Privileged register trap",
	200	[12] "Overflow trap",
	201	[13] "Conditional trap",
	202	[14] "FP Assist Exception trap",
	203	[15] "Data TLB miss fault",
	204	[16] "Non-access ITLB miss fault",
	205	[17] "Non-access DTLB miss fault",
	206	[18] "Data memory protection/unaligned access trap",
	207	[19] "Data memory break trap",
	208	[20] "TLB dirty bit trap",
	209	[21] "Page reference trap",
	210	[22] "Assist emulation trap",
	211	[25] "Taken branch trap",
	212	[26] "Data memory access rights trap",
	213	[27] "Data memory protection ID trap",
	214	[28] "Unaligned data reference trap",
	215	};
	216
0a862485 HD	217	const char *trap_name(unsigned long code)
	218	{
	219	const char *t = NULL;
	220
	221	if (code < ARRAY_SIZE(trap_description))
	222	t = trap_description[code];
	223
	224	return t ? t : "Unknown trap";
	225	}
	226
fef47e2a HD	227	/*
	228	* Print out info about fatal segfaults, if the show_unhandled_signals
	229	* sysctl is set:
	230	*/
	231	static inline void
	232	show_signal_msg(struct pt_regs *regs, unsigned long code,
	233	unsigned long address, struct task_struct *tsk,
	234	struct vm_area_struct *vma)
	235	{
	236	if (!unhandled_signal(tsk, SIGSEGV))
	237	return;
	238
	239	if (!printk_ratelimit())
	240	return;
	241
	242	pr_warn("\n");
	243	pr_warn("do_page_fault() command='%s' type=%lu address=0x%08lx",
	244	tsk->comm, code, address);
	245	print_vma_addr(KERN_CONT " in ", regs->iaoq[0]);
b391667e	246
b4a9eb4c	247	pr_cont("\ntrap #%lu: %s%c", code, trap_name(code),
b391667e HD	248	vma ? ',':'\n');
b391667e HD	249
fef47e2a	250	if (vma)
8351badf DC	251	pr_cont(" vm_start = 0x%08lx, vm_end = 0x%08lx\n",
8351badf DC	252	vma->vm_start, vma->vm_end);
fef47e2a HD	253
	254	show_regs(regs);
	255	}
	256
1da177e4 LT	257	void do_page_fault(struct pt_regs *regs, unsigned long code,
	258	unsigned long address)
	259	{
	260	struct vm_area_struct vma, prev_vma;
2d8b22de JDA	261	struct task_struct *tsk;
2d8b22de JDA	262	struct mm_struct *mm;
1da177e4	263	unsigned long acc_type;
83c54070	264	int fault;
2d8b22de	265	unsigned int flags;
1da177e4	266
699817c3	267	if (faulthandler_disabled())
1da177e4 LT	268	goto no_context;
1da177e4 LT	269
2d8b22de JDA	270	tsk = current;
	271	mm = tsk->mm;
	272	if (!mm)
	273	goto no_context;
	274
	275	flags = FAULT_FLAG_ALLOW_RETRY \| FAULT_FLAG_KILLABLE;
759496ba JW	276	if (user_mode(regs))
759496ba JW	277	flags \|= FAULT_FLAG_USER;
0772dac1 FP	278
0772dac1 FP	279	acc_type = parisc_acctyp(code, regs->iir);
759496ba JW	280	if (acc_type & VM_WRITE)
759496ba JW	281	flags \|= FAULT_FLAG_WRITE;
38057477	282	retry:
1da177e4 LT	283	down_read(&mm->mmap_sem);
	284	vma = find_vma_prev(mm, address, &prev_vma);
	285	if (!vma \|\| address < vma->vm_start)
	286	goto check_expansion;
	287	/*
	288	* Ok, we have a good vm_area for this memory access. We still need to
	289	* check the access permissions.
	290	*/
	291
	292	good_area:
	293
1da177e4 LT	294	if ((vma->vm_flags & acc_type) != acc_type)
	295	goto bad_area;
	296
	297	/*
	298	* If for any reason at all we couldn't handle the fault, make
	299	* sure we exit gracefully rather than endlessly redo the
	300	* fault.
	301	*/
	302
dcddffd4	303	fault = handle_mm_fault(vma, address, flags);
38057477 KC	304
	305	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
	306	return;
	307
83c54070	308	if (unlikely(fault & VM_FAULT_ERROR)) {
1da177e4	309	/*
67a5a59d	310	* We hit a shared mapping outside of the file, or some
6e346228 LT	311	* other thing happened to us that made us unable to
6e346228 LT	312	* handle the page fault gracefully.
1da177e4	313	*/
83c54070 NP	314	if (fault & VM_FAULT_OOM)
83c54070 NP	315	goto out_of_memory;
33692f27 LT	316	else if (fault & VM_FAULT_SIGSEGV)
33692f27 LT	317	goto bad_area;
83c54070 NP	318	else if (fault & VM_FAULT_SIGBUS)
	319	goto bad_area;
	320	BUG();
1da177e4	321	}
38057477 KC	322	if (flags & FAULT_FLAG_ALLOW_RETRY) {
	323	if (fault & VM_FAULT_MAJOR)
	324	current->maj_flt++;
	325	else
	326	current->min_flt++;
	327	if (fault & VM_FAULT_RETRY) {
	328	flags &= ~FAULT_FLAG_ALLOW_RETRY;
	329
	330	/*
	331	* No need to up_read(&mm->mmap_sem) as we would
	332	* have already released it in __lock_page_or_retry
	333	* in mm/filemap.c.
	334	*/
	335
	336	goto retry;
	337	}
	338	}
1da177e4 LT	339	up_read(&mm->mmap_sem);
	340	return;
	341
	342	check_expansion:
	343	vma = prev_vma;
	344	if (vma && (expand_stack(vma, address) == 0))
	345	goto good_area;
	346
	347	/*
	348	* Something tried to access memory that isn't in our memory map..
	349	*/
	350	bad_area:
	351	up_read(&mm->mmap_sem);
	352
	353	if (user_mode(regs)) {
	354	struct siginfo si;
	355
fef47e2a HD	356	show_signal_msg(regs, code, address, tsk, vma);
fef47e2a HD	357
1f2048fd HD	358	switch (code) {
1f2048fd HD	359	case 15: /* Data TLB miss fault/Data page fault */
49d1cb2b HD	360	/* send SIGSEGV when outside of vma */
	361	if (!vma \|\|
	362	address < vma->vm_start \|\| address > vma->vm_end) {
	363	si.si_signo = SIGSEGV;
	364	si.si_code = SEGV_MAPERR;
	365	break;
	366	}
	367
	368	/* send SIGSEGV for wrong permissions */
	369	if ((vma->vm_flags & acc_type) != acc_type) {
	370	si.si_signo = SIGSEGV;
	371	si.si_code = SEGV_ACCERR;
	372	break;
	373	}
	374
	375	/* probably address is outside of mapped file */
	376	/* fall through */
1f2048fd HD	377	case 17: /* NA data TLB miss / page fault */
	378	case 18: /* Unaligned access - PCXS only */
	379	si.si_signo = SIGBUS;
49d1cb2b	380	si.si_code = (code == 18) ? BUS_ADRALN : BUS_ADRERR;
1f2048fd HD	381	break;
	382	case 16: /* Non-access instruction TLB miss fault */
	383	case 26: /* PCXL: Data memory access rights trap */
	384	default:
	385	si.si_signo = SIGSEGV;
49d1cb2b HD	386	si.si_code = (code == 26) ? SEGV_ACCERR : SEGV_MAPERR;
49d1cb2b HD	387	break;
1f2048fd	388	}
1da177e4	389	si.si_errno = 0;
1da177e4	390	si.si_addr = (void __user *) address;
1f2048fd	391	force_sig_info(si.si_signo, &si, current);
1da177e4 LT	392	return;
	393	}
	394
	395	no_context:
	396
c61c25eb KM	397	if (!user_mode(regs) && fixup_exception(regs)) {
c61c25eb KM	398	return;
1da177e4 LT	399	}
	400
	401	parisc_terminate("Bad Address (null pointer deref?)", regs, code, address);
	402
	403	out_of_memory:
	404	up_read(&mm->mmap_sem);
53e30d02 NP	405	if (!user_mode(regs))
	406	goto no_context;
	407	pagefault_out_of_memory();
1da177e4	408	}