[mirror_ubuntu-eoan-kernel.git] / arch / arc / kernel / troubleshoot.c

/*
 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
 *
 * 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
 */

#include <linux/ptrace.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/kdev_t.h>
#include <linux/fs_struct.h>
#include <linux/proc_fs.h>
#include <linux/file.h>
#include <asm/arcregs.h>
#include <asm/irqflags.h>

/*
 * Common routine to print scratch regs (r0-r12) or callee regs (r13-r25)
 *   -Prints 3 regs per line and a CR.
 *   -To continue, callee regs right after scratch, special handling of CR
 */
static noinline void print_reg_file(long *reg_rev, int start_num)
{
	unsigned int i;
	char buf[512];
	int n = 0, len = sizeof(buf);

	for (i = start_num; i < start_num + 13; i++) {
		n += scnprintf(buf + n, len - n, "r%02u: 0x%08lx\t",
			       i, (unsigned long)*reg_rev);

		if (((i + 1) % 3) == 0)
			n += scnprintf(buf + n, len - n, "\n");

		/* because pt_regs has regs reversed: r12..r0, r25..r13 */
		if (is_isa_arcv2() && start_num == 0)
			reg_rev++;
		else
			reg_rev--;
	}

	if (start_num != 0)
		n += scnprintf(buf + n, len - n, "\n\n");

	/* To continue printing callee regs on same line as scratch regs */
	if (start_num == 0)
		pr_info("%s", buf);
	else
		pr_cont("%s\n", buf);
}

static void show_callee_regs(struct callee_regs *cregs)
{
	print_reg_file(&(cregs->r13), 13);
}

static void print_task_path_n_nm(struct task_struct *tsk, char *buf)
{
	char *path_nm = NULL;
	struct mm_struct *mm;
	struct file *exe_file;

	mm = get_task_mm(tsk);
	if (!mm)
		goto done;

	exe_file = get_mm_exe_file(mm);
	mmput(mm);

	if (exe_file) {
		path_nm = file_path(exe_file, buf, 255);
		fput(exe_file);
	}

done:
	pr_info("Path: %s\n", !IS_ERR(path_nm) ? path_nm : "?");
}

static void show_faulting_vma(unsigned long address, char *buf)
{
	struct vm_area_struct *vma;
	struct inode *inode;
	unsigned long ino = 0;
	dev_t dev = 0;
	char *nm = buf;
	struct mm_struct *active_mm = current->active_mm;

	/* can't use print_vma_addr() yet as it doesn't check for
	 * non-inclusive vma
	 */
	down_read(&active_mm->mmap_sem);
	vma = find_vma(active_mm, address);

	/* check against the find_vma( ) behaviour which returns the next VMA
	 * if the container VMA is not found
	 */
	if (vma && (vma->vm_start <= address)) {
		struct file *file = vma->vm_file;
		if (file) {
			nm = file_path(file, buf, PAGE_SIZE - 1);
			inode = file_inode(vma->vm_file);
			dev = inode->i_sb->s_dev;
			ino = inode->i_ino;
		}
		pr_info("    @off 0x%lx in [%s]\n"
			"    VMA: 0x%08lx to 0x%08lx\n",
			vma->vm_start < TASK_UNMAPPED_BASE ?
				address : address - vma->vm_start,
			nm, vma->vm_start, vma->vm_end);
	} else
		pr_info("    @No matching VMA found\n");

	up_read(&active_mm->mmap_sem);
}

static void show_ecr_verbose(struct pt_regs *regs)
{
	unsigned int vec, cause_code;
	unsigned long address;

	pr_info("\n[ECR   ]: 0x%08lx => ", regs->event);

	/* For Data fault, this is data address not instruction addr */
	address = current->thread.fault_address;

	vec = regs->ecr_vec;
	cause_code = regs->ecr_cause;

	/* For DTLB Miss or ProtV, display the memory involved too */
	if (vec == ECR_V_DTLB_MISS) {
		pr_cont("Invalid %s @ 0x%08lx by insn @ 0x%08lx\n",
		       (cause_code == 0x01) ? "Read" :
		       ((cause_code == 0x02) ? "Write" : "EX"),
		       address, regs->ret);
	} else if (vec == ECR_V_ITLB_MISS) {
		pr_cont("Insn could not be fetched\n");
	} else if (vec == ECR_V_MACH_CHK) {
		pr_cont("%s\n", (cause_code == 0x0) ?
					"Double Fault" : "Other Fatal Err");

	} else if (vec == ECR_V_PROTV) {
		if (cause_code == ECR_C_PROTV_INST_FETCH)
			pr_cont("Execute from Non-exec Page\n");
		else if (cause_code == ECR_C_PROTV_MISALIG_DATA)
			pr_cont("Misaligned r/w from 0x%08lx\n", address);
		else
			pr_cont("%s access not allowed on page\n",
				(cause_code == 0x01) ? "Read" :
				((cause_code == 0x02) ? "Write" : "EX"));
	} else if (vec == ECR_V_INSN_ERR) {
		pr_cont("Illegal Insn\n");
#ifdef CONFIG_ISA_ARCV2
	} else if (vec == ECR_V_MEM_ERR) {
		if (cause_code == 0x00)
			pr_cont("Bus Error from Insn Mem\n");
		else if (cause_code == 0x10)
			pr_cont("Bus Error from Data Mem\n");
		else
			pr_cont("Bus Error, check PRM\n");
#endif
	} else {
		pr_cont("Check Programmer's Manual\n");
	}
}

/************************************************************************
 *  API called by rest of kernel
 ***********************************************************************/

void show_regs(struct pt_regs *regs)
{
	struct task_struct *tsk = current;
	struct callee_regs *cregs;
	char *buf;

	buf = (char *)__get_free_page(GFP_TEMPORARY);
	if (!buf)
		return;

	print_task_path_n_nm(tsk, buf);
	show_regs_print_info(KERN_INFO);

	show_ecr_verbose(regs);

	pr_info("[EFA   ]: 0x%08lx\n[BLINK ]: %pS\n[ERET  ]: %pS\n",
		current->thread.fault_address,
		(void *)regs->blink, (void *)regs->ret);

	if (user_mode(regs))
		show_faulting_vma(regs->ret, buf); /* faulting code, not data */

	pr_info("[STAT32]: 0x%08lx", regs->status32);

#define STS_BIT(r, bit)	r->status32 & STATUS_##bit##_MASK ? #bit" " : ""

#ifdef CONFIG_ISA_ARCOMPACT
	pr_cont(" : %2s%2s%2s%2s%2s%2s%2s\n",
			(regs->status32 & STATUS_U_MASK) ? "U " : "K ",
			STS_BIT(regs, DE), STS_BIT(regs, AE),
			STS_BIT(regs, A2), STS_BIT(regs, A1),
			STS_BIT(regs, E2), STS_BIT(regs, E1));
#else
	pr_cont(" : %2s%2s%2s%2s\n",
			STS_BIT(regs, IE),
			(regs->status32 & STATUS_U_MASK) ? "U " : "K ",
			STS_BIT(regs, DE), STS_BIT(regs, AE));
#endif
	pr_info("BTA: 0x%08lx\t SP: 0x%08lx\t FP: 0x%08lx\n",
		regs->bta, regs->sp, regs->fp);
	pr_info("LPS: 0x%08lx\tLPE: 0x%08lx\tLPC: 0x%08lx\n",
	       regs->lp_start, regs->lp_end, regs->lp_count);

	/* print regs->r0 thru regs->r12
	 * Sequential printing was generating horrible code
	 */
	print_reg_file(&(regs->r0), 0);

	/* If Callee regs were saved, display them too */
	cregs = (struct callee_regs *)current->thread.callee_reg;
	if (cregs)
		show_callee_regs(cregs);

	free_page((unsigned long)buf);
}

void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
			    unsigned long address)
{
	current->thread.fault_address = address;

	/* Caller and Callee regs */
	show_regs(regs);

	/* Show stack trace if this Fatality happened in kernel mode */
	if (!user_mode(regs))
		show_stacktrace(current, regs);
}

#ifdef CONFIG_DEBUG_FS

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <linux/namei.h>
#include <linux/debugfs.h>

static struct dentry *test_dentry;
static struct dentry *test_dir;
static struct dentry *test_u32_dentry;

static u32 clr_on_read = 1;

#ifdef CONFIG_ARC_DBG_TLB_MISS_COUNT
u32 numitlb, numdtlb, num_pte_not_present;

static int fill_display_data(char *kbuf)
{
	size_t num = 0;
	num += sprintf(kbuf + num, "I-TLB Miss %x\n", numitlb);
	num += sprintf(kbuf + num, "D-TLB Miss %x\n", numdtlb);
	num += sprintf(kbuf + num, "PTE not present %x\n", num_pte_not_present);

	if (clr_on_read)
		numitlb = numdtlb = num_pte_not_present = 0;

	return num;
}

static int tlb_stats_open(struct inode *inode, struct file *file)
{
	file->private_data = (void *)__get_free_page(GFP_KERNEL);
	return 0;
}

/* called on user read(): display the counters */
static ssize_t tlb_stats_output(struct file *file,	/* file descriptor */
				char __user *user_buf,	/* user buffer */
				size_t len,		/* length of buffer */
				loff_t *offset)		/* offset in the file */
{
	size_t num;
	char *kbuf = (char *)file->private_data;

	/* All of the data can he shoved in one iteration */
	if (*offset != 0)
		return 0;

	num = fill_display_data(kbuf);

	/* simple_read_from_buffer() is helper for copy to user space
	   It copies up to @2 (num) bytes from kernel buffer @4 (kbuf) at offset
	   @3 (offset) into the user space address starting at @1 (user_buf).
	   @5 (len) is max size of user buffer
	 */
	return simple_read_from_buffer(user_buf, num, offset, kbuf, len);
}

/* called on user write : clears the counters */
static ssize_t tlb_stats_clear(struct file *file, const char __user *user_buf,
			       size_t length, loff_t *offset)
{
	numitlb = numdtlb = num_pte_not_present = 0;
	return length;
}

static int tlb_stats_close(struct inode *inode, struct file *file)
{
	free_page((unsigned long)(file->private_data));
	return 0;
}

static const struct file_operations tlb_stats_file_ops = {
	.read = tlb_stats_output,
	.write = tlb_stats_clear,
	.open = tlb_stats_open,
	.release = tlb_stats_close
};
#endif

static int __init arc_debugfs_init(void)
{
	test_dir = debugfs_create_dir("arc", NULL);

#ifdef CONFIG_ARC_DBG_TLB_MISS_COUNT
	test_dentry = debugfs_create_file("tlb_stats", 0444, test_dir, NULL,
					  &tlb_stats_file_ops);
#endif

	test_u32_dentry =
	    debugfs_create_u32("clr_on_read", 0444, test_dir, &clr_on_read);

	return 0;
}

module_init(arc_debugfs_init);

static void __exit arc_debugfs_exit(void)
{
	debugfs_remove(test_u32_dentry);
	debugfs_remove(test_dentry);
	debugfs_remove(test_dir);
}
module_exit(arc_debugfs_exit);

#endif
Commit	Line	Data
c08098f2 VG	1	/*
	2	* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	*/
	7
	8	#include <linux/ptrace.h>
0ef88a54 VG	9	#include <linux/module.h>
	10	#include <linux/mm.h>
	11	#include <linux/fs.h>
	12	#include <linux/kdev_t.h>
	13	#include <linux/fs_struct.h>
	14	#include <linux/proc_fs.h>
	15	#include <linux/file.h>
	16	#include <asm/arcregs.h>
1f6ccfff	17	#include <asm/irqflags.h>
0ef88a54 VG	18
	19	/*
	20	* Common routine to print scratch regs (r0-r12) or callee regs (r13-r25)
	21	* -Prints 3 regs per line and a CR.
	22	* -To continue, callee regs right after scratch, special handling of CR
	23	*/
	24	static noinline void print_reg_file(long *reg_rev, int start_num)
	25	{
	26	unsigned int i;
	27	char buf[512];
	28	int n = 0, len = sizeof(buf);
	29
0ef88a54 VG	30	for (i = start_num; i < start_num + 13; i++) {
	31	n += scnprintf(buf + n, len - n, "r%02u: 0x%08lx\t",
	32	i, (unsigned long)*reg_rev);
	33
	34	if (((i + 1) % 3) == 0)
	35	n += scnprintf(buf + n, len - n, "\n");
	36
bd3c8b11	37	/* because pt_regs has regs reversed: r12..r0, r25..r13 */
1f6ccfff VG	38	if (is_isa_arcv2() && start_num == 0)
	39	reg_rev++;
	40	else
	41	reg_rev--;
0ef88a54 VG	42	}
	43
	44	if (start_num != 0)
	45	n += scnprintf(buf + n, len - n, "\n\n");
	46
bd3c8b11 VG	47	/* To continue printing callee regs on same line as scratch regs */
	48	if (start_num == 0)
	49	pr_info("%s", buf);
	50	else
	51	pr_cont("%s\n", buf);
0ef88a54 VG	52	}
	53
	54	static void show_callee_regs(struct callee_regs *cregs)
	55	{
	56	print_reg_file(&(cregs->r13), 13);
	57	}
	58
be2a7fce	59	static void print_task_path_n_nm(struct task_struct tsk, char buf)
0ef88a54	60	{
0ef88a54 VG	61	char *path_nm = NULL;
	62	struct mm_struct *mm;
	63	struct file *exe_file;
	64
	65	mm = get_task_mm(tsk);
	66	if (!mm)
	67	goto done;
	68
	69	exe_file = get_mm_exe_file(mm);
	70	mmput(mm);
	71
	72	if (exe_file) {
9bf39ab2	73	path_nm = file_path(exe_file, buf, 255);
0ef88a54	74	fput(exe_file);
0ef88a54 VG	75	}
	76
	77	done:
9bf39ab2	78	pr_info("Path: %s\n", !IS_ERR(path_nm) ? path_nm : "?");
0ef88a54	79	}
0ef88a54 VG	80
	81	static void show_faulting_vma(unsigned long address, char *buf)
	82	{
	83	struct vm_area_struct *vma;
	84	struct inode *inode;
	85	unsigned long ino = 0;
	86	dev_t dev = 0;
	87	char *nm = buf;
5040573e	88	struct mm_struct *active_mm = current->active_mm;
0ef88a54	89
bd3c8b11 VG	90	/* can't use print_vma_addr() yet as it doesn't check for
	91	* non-inclusive vma
	92	*/
5040573e DB	93	down_read(&active_mm->mmap_sem);
5040573e DB	94	vma = find_vma(active_mm, address);
0ef88a54 VG	95
	96	/* check against the find_vma( ) behaviour which returns the next VMA
	97	* if the container VMA is not found
	98	*/
	99	if (vma && (vma->vm_start <= address)) {
	100	struct file *file = vma->vm_file;
	101	if (file) {
9bf39ab2	102	nm = file_path(file, buf, PAGE_SIZE - 1);
e77e4300	103	inode = file_inode(vma->vm_file);
0ef88a54 VG	104	dev = inode->i_sb->s_dev;
	105	ino = inode->i_ino;
	106	}
	107	pr_info(" @off 0x%lx in [%s]\n"
bd3c8b11 VG	108	" VMA: 0x%08lx to 0x%08lx\n",
	109	vma->vm_start < TASK_UNMAPPED_BASE ?
	110	address : address - vma->vm_start,
	111	nm, vma->vm_start, vma->vm_end);
5040573e	112	} else
0ef88a54	113	pr_info(" @No matching VMA found\n");
5040573e DB	114
5040573e DB	115	up_read(&active_mm->mmap_sem);
0ef88a54 VG	116	}
	117
	118	static void show_ecr_verbose(struct pt_regs *regs)
	119	{
502a0c77	120	unsigned int vec, cause_code;
0ef88a54 VG	121	unsigned long address;
0ef88a54 VG	122
502a0c77	123	pr_info("\n[ECR ]: 0x%08lx => ", regs->event);
0ef88a54 VG	124
	125	/* For Data fault, this is data address not instruction addr */
	126	address = current->thread.fault_address;
	127
502a0c77 VG	128	vec = regs->ecr_vec;
502a0c77 VG	129	cause_code = regs->ecr_cause;
0ef88a54 VG	130
	131	/* For DTLB Miss or ProtV, display the memory involved too */
	132	if (vec == ECR_V_DTLB_MISS) {
65464152 VG	133	pr_cont("Invalid %s @ 0x%08lx by insn @ 0x%08lx\n",
	134	(cause_code == 0x01) ? "Read" :
	135	((cause_code == 0x02) ? "Write" : "EX"),
0ef88a54 VG	136	address, regs->ret);
	137	} else if (vec == ECR_V_ITLB_MISS) {
	138	pr_cont("Insn could not be fetched\n");
	139	} else if (vec == ECR_V_MACH_CHK) {
	140	pr_cont("%s\n", (cause_code == 0x0) ?
	141	"Double Fault" : "Other Fatal Err");
	142
	143	} else if (vec == ECR_V_PROTV) {
	144	if (cause_code == ECR_C_PROTV_INST_FETCH)
	145	pr_cont("Execute from Non-exec Page\n");
0ef88a54 VG	146	else if (cause_code == ECR_C_PROTV_MISALIG_DATA)
0ef88a54 VG	147	pr_cont("Misaligned r/w from 0x%08lx\n", address);
65464152 VG	148	else
	149	pr_cont("%s access not allowed on page\n",
	150	(cause_code == 0x01) ? "Read" :
	151	((cause_code == 0x02) ? "Write" : "EX"));
0ef88a54 VG	152	} else if (vec == ECR_V_INSN_ERR) {
0ef88a54 VG	153	pr_cont("Illegal Insn\n");
1f6ccfff VG	154	#ifdef CONFIG_ISA_ARCV2
	155	} else if (vec == ECR_V_MEM_ERR) {
	156	if (cause_code == 0x00)
	157	pr_cont("Bus Error from Insn Mem\n");
	158	else if (cause_code == 0x10)
	159	pr_cont("Bus Error from Data Mem\n");
	160	else
	161	pr_cont("Bus Error, check PRM\n");
	162	#endif
0ef88a54 VG	163	} else {
	164	pr_cont("Check Programmer's Manual\n");
	165	}
	166	}
	167
	168	/************************************************************************
	169	* API called by rest of kernel
	170	***********************************************************************/
c08098f2 VG	171
	172	void show_regs(struct pt_regs *regs)
	173	{
0ef88a54 VG	174	struct task_struct *tsk = current;
	175	struct callee_regs *cregs;
	176	char *buf;
	177
	178	buf = (char *)__get_free_page(GFP_TEMPORARY);
	179	if (!buf)
	180	return;
	181
	182	print_task_path_n_nm(tsk, buf);
a43cb95d	183	show_regs_print_info(KERN_INFO);
0ef88a54	184
502a0c77	185	show_ecr_verbose(regs);
0ef88a54	186
bd3c8b11 VG	187	pr_info("[EFA ]: 0x%08lx\n[BLINK ]: %pS\n[ERET ]: %pS\n",
	188	current->thread.fault_address,
	189	(void )regs->blink, (void )regs->ret);
0ef88a54	190
bd3c8b11 VG	191	if (user_mode(regs))
bd3c8b11 VG	192	show_faulting_vma(regs->ret, buf); /* faulting code, not data */
0ef88a54	193
bd3c8b11 VG	194	pr_info("[STAT32]: 0x%08lx", regs->status32);
bd3c8b11 VG	195
1f6ccfff	196	#define STS_BIT(r, bit) r->status32 & STATUS_##bit##_MASK ? #bit" " : ""
0ef88a54	197
1f6ccfff VG	198	#ifdef CONFIG_ISA_ARCOMPACT
	199	pr_cont(" : %2s%2s%2s%2s%2s%2s%2s\n",
	200	(regs->status32 & STATUS_U_MASK) ? "U " : "K ",
	201	STS_BIT(regs, DE), STS_BIT(regs, AE),
	202	STS_BIT(regs, A2), STS_BIT(regs, A1),
	203	STS_BIT(regs, E2), STS_BIT(regs, E1));
	204	#else
	205	pr_cont(" : %2s%2s%2s%2s\n",
	206	STS_BIT(regs, IE),
	207	(regs->status32 & STATUS_U_MASK) ? "U " : "K ",
	208	STS_BIT(regs, DE), STS_BIT(regs, AE));
	209	#endif
bd3c8b11 VG	210	pr_info("BTA: 0x%08lx\t SP: 0x%08lx\t FP: 0x%08lx\n",
bd3c8b11 VG	211	regs->bta, regs->sp, regs->fp);
0ef88a54 VG	212	pr_info("LPS: 0x%08lx\tLPE: 0x%08lx\tLPC: 0x%08lx\n",
	213	regs->lp_start, regs->lp_end, regs->lp_count);
	214
	215	/* print regs->r0 thru regs->r12
	216	* Sequential printing was generating horrible code
	217	*/
	218	print_reg_file(&(regs->r0), 0);
	219
	220	/* If Callee regs were saved, display them too */
	221	cregs = (struct callee_regs *)current->thread.callee_reg;
	222	if (cregs)
	223	show_callee_regs(cregs);
	224
	225	free_page((unsigned long)buf);
c08098f2 VG	226	}
	227
	228	void show_kernel_fault_diag(const char str, struct pt_regs regs,
38a9ff6d	229	unsigned long address)
c08098f2	230	{
0ef88a54	231	current->thread.fault_address = address;
0ef88a54 VG	232
	233	/* Caller and Callee regs */
	234	show_regs(regs);
	235
	236	/* Show stack trace if this Fatality happened in kernel mode */
	237	if (!user_mode(regs))
	238	show_stacktrace(current, regs);
c08098f2	239	}
0ef88a54 VG	240
	241	#ifdef CONFIG_DEBUG_FS
	242
	243	#include <linux/module.h>
	244	#include <linux/fs.h>
	245	#include <linux/mount.h>
	246	#include <linux/pagemap.h>
	247	#include <linux/init.h>
	248	#include <linux/namei.h>
	249	#include <linux/debugfs.h>
	250
	251	static struct dentry *test_dentry;
	252	static struct dentry *test_dir;
	253	static struct dentry *test_u32_dentry;
	254
	255	static u32 clr_on_read = 1;
	256
	257	#ifdef CONFIG_ARC_DBG_TLB_MISS_COUNT
	258	u32 numitlb, numdtlb, num_pte_not_present;
	259
	260	static int fill_display_data(char *kbuf)
	261	{
	262	size_t num = 0;
	263	num += sprintf(kbuf + num, "I-TLB Miss %x\n", numitlb);
	264	num += sprintf(kbuf + num, "D-TLB Miss %x\n", numdtlb);
	265	num += sprintf(kbuf + num, "PTE not present %x\n", num_pte_not_present);
	266
	267	if (clr_on_read)
	268	numitlb = numdtlb = num_pte_not_present = 0;
	269
	270	return num;
	271	}
	272
	273	static int tlb_stats_open(struct inode inode, struct file file)
	274	{
	275	file->private_data = (void *)__get_free_page(GFP_KERNEL);
	276	return 0;
	277	}
	278
2547476a	279	/* called on user read(): display the counters */
0ef88a54 VG	280	static ssize_t tlb_stats_output(struct file file, / file descriptor */
	281	char __user user_buf, / user buffer */
	282	size_t len, /* length of buffer */
	283	loff_t offset) / offset in the file */
	284	{
	285	size_t num;
	286	char kbuf = (char )file->private_data;
	287
	288	/* All of the data can he shoved in one iteration */
	289	if (*offset != 0)
	290	return 0;
	291
	292	num = fill_display_data(kbuf);
	293
	294	/* simple_read_from_buffer() is helper for copy to user space
	295	It copies up to @2 (num) bytes from kernel buffer @4 (kbuf) at offset
	296	@3 (offset) into the user space address starting at @1 (user_buf).
	297	@5 (len) is max size of user buffer
	298	*/
	299	return simple_read_from_buffer(user_buf, num, offset, kbuf, len);
	300	}
	301
	302	/* called on user write : clears the counters */
	303	static ssize_t tlb_stats_clear(struct file file, const char __user user_buf,
	304	size_t length, loff_t *offset)
	305	{
	306	numitlb = numdtlb = num_pte_not_present = 0;
	307	return length;
	308	}
	309
	310	static int tlb_stats_close(struct inode inode, struct file file)
	311	{
	312	free_page((unsigned long)(file->private_data));
	313	return 0;
	314	}
	315
	316	static const struct file_operations tlb_stats_file_ops = {
	317	.read = tlb_stats_output,
	318	.write = tlb_stats_clear,
	319	.open = tlb_stats_open,
	320	.release = tlb_stats_close
	321	};
	322	#endif
	323
	324	static int __init arc_debugfs_init(void)
	325	{
	326	test_dir = debugfs_create_dir("arc", NULL);
	327
	328	#ifdef CONFIG_ARC_DBG_TLB_MISS_COUNT
	329	test_dentry = debugfs_create_file("tlb_stats", 0444, test_dir, NULL,
	330	&tlb_stats_file_ops);
	331	#endif
	332
	333	test_u32_dentry =
	334	debugfs_create_u32("clr_on_read", 0444, test_dir, &clr_on_read);
	335
	336	return 0;
	337	}
	338
	339	module_init(arc_debugfs_init);
	340
	341	static void __exit arc_debugfs_exit(void)
	342	{
	343	debugfs_remove(test_u32_dentry);
344	debugfs_remove(test_dentry);
345	debugfs_remove(test_dir);
346	}
347	module_exit(arc_debugfs_exit);
348
349	#endif